National Emission Standards for Hazardous Air Pollutants: Proposed Standards for Hazardous Air Pollutants for Hazardous Waste Combustors (Phase I Final Replacement Standards and Phase II)

[Federal Register: April 20, 2004 (Volume 69, Number 76)]
[Proposed Rules]
[Page 21197-21385]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20ap04-25]
[[Page 21198]]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 63, 264, 265, 266, 270, and 271
[FRL-7644-1]
RIN 2050-AE01

National Emission Standards for Hazardous Air Pollutants:
Proposed Standards for Hazardous Air Pollutants for Hazardous Waste
Combustors (Phase I Final Replacement Standards and Phase II)

AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.

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SUMMARY: This action proposes national emission standards for hazardous
air pollutants (NESHAP) for hazardous waste combustors. These
combustors include hazardous waste burning incinerators, cement kilns,
lightweight aggregate kilns, industrial/commercial/institutional
boilers and process heaters, and hydrochloric acid production furnaces,
known collectively as hazardous waste combustors (HWCs). EPA has
identified these HWCs as major sources of hazardous air pollutant (HAP)
emissions. These proposed standards will, when final, implement section
112(d) of the Clean Air Act (CAA) by requiring hazardous waste
combustors to meet HAP emission standards reflecting the application of
the maximum achievable control technology (MACT).
The HAP emitted by facilities in the incinerator, cement kiln,
lightweight aggregate kiln, industrial/commercial/institutional boiler,
process heater, and hydrochloric acid production furnace source
categories include arsenic, beryllium, cadmium, chromium, dioxins and
furans, hydrogen chloride and chlorine gas, lead, manganese, and
mercury. Exposure to these substances has been demonstrated to cause
adverse health effects such as irritation on the lung, skin, and mucus
membranes, effects on the central nervous system, kidney damage, and
cancer. The adverse health effects associated with the exposure to
these specific HAP are further described in the preamble. In general,
these findings have only been shown with concentrations higher than
those typically in the ambient air.
This action also presents our tentative decision regarding the
February 28, 2002, petition for rulemaking submitted by the Cement Kiln
Recycling Coalition to the Administrator, relating to EPA's
implementation of the so-called omnibus permitting authority under
section 3005(c) of the Resource Conservation and Recovery Act (RCRA),
which requires that each permit issued under RCRA contain such terms
and conditions as are determined necessary to protect human health and
the environment. In that petition, the Cement Kiln Recycling Coalition
requests that we repeal the existing site-specific risk assessment
policy and technical guidance for hazardous waste combustors and that
we promulgate the policy and guidance as rules in accordance with the
Administrative Procedure Act if we continue to believe that site-
specific risk assessments may be necessary.

DATES: Submit comments on or before July 6, 2004.

ADDRESSES: Submit your comments, identified by Docket ID No. OAR-2004-
0022 by one of the following methods:
? Federal eRulemaking Portal: http://www.regulations.gov.
Follow the on-line instructions for submitting
comments.
? Agency Web site: http://www.epa.gov/edocket.
EDOCKET, EPA's electronic public docket and comment system, is EPA's
preferred method for receiving comments. Follow the on-line
instructions for submitting comments.
? E-mail: http://www.epa.gov/edocket.
? Fax: 202-566-1741.
? Mail: OAR Docket, Environmental Protection
Agency, Mailcode: B102, 1200 Pennsylvania Ave., NW., Washington, DC
20460. Please include a total of 2 copies.
? Hand Delivery: EPA/DC, EPA West, Room B102, 1301
Constitution Ave., NW., Washington, DC. Such deliveries are only
accepted during the Docket's normal hours of operation, and special
arrangements should be made for deliveries of boxed information.
Instructions: Direct your comments to Docket ID No. OAR-2004-0022.
EPA's policy is that all comments received will be included in the
public docket without change and may be made available online at
http://www.epa.gov/edocket, including any personal information provided,
unless the comment includes information claimed to be Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Do not submit information that you consider to
be CBI or otherwise protected through EDOCKET, regulations.gov, or e-
mail. The EPA EDOCKET and the federal regulations.gov Web sites are
``anonymous access'' systems, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through EDOCKET or regulations.gov, your e-mail address will be
automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses. For additional information about EPA's public
docket visit EDOCKET on-line or see the Federal Register of May 31,
2002 (67 FR 38102).
For additional instructions on submitting comments, go to unit II
of the SUPPLEMENTARY INFORMATION section of this document.
Docket: All documents in the docket are listed in the EDOCKET index
at http://www.epa.gov/edocket. Although listed in the index, some
information is not publicly available, i.e., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, is not placed on the Internet and will be
publicly available only in hard copy form. Publicly available docket
materials are available either electronically in EDOCKET or in hard
copy at the OAR Docket, EPA/DC, EPA West, Room B102, 1301 Constitution
Ave., NW., Washington, DC. The Public Reading Room is open from 8:30
a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The
telephone number for the Public Reading Room is (202) 566-1744, and the
telephone number for the OAR Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For general information, call the RCRA
Call Center at 1-800-424-9346 or TDD 1-800-553-7672 (hearing impaired).
Callers within the Washington Metropolitan Area must dial 703-412-9810
or TDD 703-412-3323 (hearing impaired). The RCRA Call Center is open
Monday-Friday, 9 a.m. to 4 p.m., eastern standard time. For more
information about this proposal, contact Michael Galbraith at 703-605-
0567, or galbraith.michael@epa.gov.

SUPPLEMENTARY INFORMATION:

I. Regulated Entities

The promulgation of the proposed rule would affect the following North

[[Page 21199]]

American Industrial Classification System (NAICS) and Standard
Industrial Classification (SIC) codes:

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Examples of potentially
Category NAICS code SIC code regulated entities
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Any industry that combusts 562211............................. 4953 Incinerator, hazardous
hazardous waste as defined in waste.
the proposed rule.
327310............................. 3241 Cement manufacturing,
clinker production.
327992............................. 3295 Ground or treated
mineral and earth
manufacturing.
325................................ 28 Chemical Manufacturers.
324................................ 29 Petroleum Refiners.
331................................ 33 Primary Aluminum.
333................................ 38 Photographic equipment
and supplies.
488, 561, 562...................... 49 Sanitary Services,
N.E.C.
421................................ 50 Scrap and waste
materials.
422................................ 51 Chemical and Allied
Products, N.E.C.
512, 541, 561, 812................. 73 Business Services,
N.E.C.
512, 514, 541, 711................. 89 Services, N.E.C.
924................................ 95 Air, Water and Solid
Waste Management.
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This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This table lists examples of the types of entries EPA is now
aware could potentially be regulated by this action. Other types of
entities not listed could also be affected. To determine whether your
facility, company, business, organization, etc., is regulated by this
action, you should examine the applicability criteria in Part II of
this preamble. If you have any questions regarding the applicability of
this action to a particular entity, consult the person listed in the
preceding FOR FURTHER INFORMATION CONTACT section.

II. What Should I Consider as I Prepare My Comments for EPA?

1. Submitting CBI. Do not submit this information to EPA through
EDOCKET, regulations.gov or e-mail. Clearly mark the part or all of the
information that you claim to be CBI. For CBI information in a disk or
CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM as
CBI and then identify electronically within the disk or CD-ROM the
specific information that is claimed as CBI). In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
2. Tips for Preparing Your Comments. When submitting comments,
remember to:
A. Identify the rulemaking by docket number and other identifying
information (subject heading, Federal Register date and page number).
B. Follow directions--The agency may ask you to respond to specific
questions or organize comments by referencing a Code of Federal
Regulations (CFR) part or section number.
C. Explain why you agree or disagree; suggest alternatives and
substitute language for your requested changes.
D. Describe any assumptions and provide any technical information
and/or data that you used.
E. If you estimate potential costs or burdens, explain how you
arrived at your estimate in sufficient detail to allow for it to be
reproduced.
F. Provide specific examples to illustrate your concerns, and
suggest alternatives.
G. Explain your views as clearly as possible, avoiding the use of
profanity or personal threats.
H. Make sure to submit your comments by the comment period deadline
identified.

Outline

Part One: Background and Summary

I. Background Information
A. What Criteria Are Used in the Development of NESHAP?
B. What Is the Regulatory Development Background of the Source
Categories in the Proposed Rule?
C. What Is the Statutory Authority for this Standard?
D. What Is the Relationship Between the Proposed Rule and Other
MACT Combustion Rules?
E. What Are the Health Effects Associated with Pollutants
Emitted by Hazardous Waste Combustors?
II. Summary of the Proposed Rule
A. What Source Categories Are Affected by the Proposed Rule?
B. What HAP Are Emitted?
C. Does Today's Proposed Rule Apply to My Source?
D. What Emissions Limitations Must I Meet?
E. What Are the Testing and Initial Compliance Requirements?
F. What Are the Continuous Compliance Requirements?
G. What Are the Notification, Recordkeeping, and Reporting Requirements?

Part Two: Rationale for the Proposed Rule

I. How Did EPA Determine Which Hazardous Waste Combustion Sources
Would Be Regulated?
A. How Are Area Sources Regulated?
B. What Hazardous Waste Combustors Are Not Covered by this Proposal?
C. How Would Sulfuric Acid Regeneration Facilities Be Regulated?
II. What Subcategorization Considerations Did EPA Evaluate?
A. What Subcategorization Options Did We Consider for Incinerators?
B. What Subcategorization Options Did We Consider for Cement Kilns?
C. What Subcategorization Options Did We Consider for
Lightweight Aggregate Kilns?
D. What Subcategorization Options Did We Consider for Boilers?
E. What Subcategorization Options Did We Consider for
Hydrochloric Acid Production Furnaces?
III. What Data and Information Did EPA Consider to Establish the
Proposed Standards?
A. Data Base for Phase I Sources
B. Data Base for Phase II Sources
C. Classification of the Emission Data
D. Invitation to Comment on Data Base
IV. How Did EPA Select the Format for the Proposed Rule?
A. What Is the Rationale for Generally Selecting an Emission
Limit Format Rather than a Percent Reduction Format?
B. What Is the Rationale for Selecting a Hazardous Waste Thermal
Emissions Format for Some Standards, and an Emissions Concentration
Format for Others?
C. What Is the Rationale for Selecting Surrogates to Control
Multiple HAP?
D. What Is the Rationale for Requiring Compliance with Operating
Parameter Limits to Ensure Compliance with Emission Standards?

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V. How Did EPA Determine the Proposed Emission Limitations for New
and Existing Units?
A. How Did EPA Determine the Proposed Emission Limitations for
New Units?
B. How Did EPA Determine the Proposed Emission Limitations for
Existing Units?
VI. How Did EPA Determine the MACT Floor for Existing and New Units?
A. What MACT Methodology Approaches Are Used to Identify the
Best Performers for the Proposed Floors, and When Are They Applied?
B. How Did EPA Select the Data to Represent Each Source When
Determining Floor Levels?
C. How Did We Evaluate Whether It Is Appropriate to Issue
Separate Emissions Standards for Various Subcategories?
D. How Did We Rank Each Source's Performance Levels to Identify
the Best Performing Sources for the Three MACT Methodologies?
E. How Did EPA Calculate Floor Levels That Are Achievable for
the Average of the Best Performing Sources?
F. Why Did EPA Default to the Interim Standards When Establishing Floors?
G. What Other Options Did EPA Consider?
VII. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Incinerators?
A. What Are the Proposed Standards for Dioxin and Furan?
B. What Are the Proposed Standards for Mercury?
C. What Are the Proposed Standards for Particulate Matter?
D. What Are the Proposed Standards for Semivolatile Metals?
E. What Are the Proposed Standards for Low Volatile Metals?
F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?
G. What Are the Standards for Hydrocarbons and Carbon Monoxide?
H. What Are the Standards for Destruction and Removal Efficiency?
VIII. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Cement Kilns?
A. What Are the Proposed Standards for Dioxin and Furan?
B. What Are the Proposed Standards for Mercury?
C. What Are the Proposed Standards for Particulate Matter?
D. What Are the Proposed Standards for Semivolatile Metals?
E. What Are the Proposed Standards for Low Volatile Metals?
F. What Are the Proposed Standards for Hydrogen Chloride and
Chlorine Gas?
G. What Are the Standards for Hydrocarbons and Carbon Monoxide?
H. What Are the Standards for Destruction and Removal Efficiency?
IX. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Lightweight Aggregate Kilns?
A. What Are the Proposed Standards for Dioxin and Furan?
B. What Are the Proposed Standards for Mercury?
C. What Are the Proposed Standards for Particulate Matter?
D. What Are the Proposed Standards for Semivolatile Metals?
E. What Are the Proposed Standards for Low Volatile Metals?
F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?
G. What Are the Standards for Hydrocarbons and Carbon Monoxide?
H. What Are the Standards for Destruction and Removal Efficiency?
X. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Solid Fuel-Fired Boilers?
A. What Is the Rationale for the Proposed Standards for Dioxin and Furan?
B. What Is the Rationale for the Proposed Standards for Mercury?
C. What Is the Rationale for the Proposed Standards for
Particulate Matter?
D. What Is the Rationale for the Proposed Standards for
Semivolatile Metals?
E. What Is the Rationale for the Proposed Standards for Low
Volatile Metals?
F. What Is the Rationale for the Proposed Standards for Total Chlorine?
G. What Is the Rationale for the Proposed Standards for Carbon
Monoxide or Hydrocarbons?
H. What Is the Rationale for the Proposed Standard for
Destruction and Removal Efficiency?
XI. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Liquid Fuel-Fired Boilers?
A. What Are the Proposed Standards for Dioxin and Furan?
B. What Is the Rationale for the Proposed Standards for Mercury?
C. What Is the Rationale for the Proposed Standards for Particulate Matter?
D. What Is the Rationale for the Proposed Standards for Semivolatile Metals?
E. What Is the Rationale for the Proposed Standards for Chromium?
F. What Is the Rationale for the Proposed Standards for Total Chlorine?
G. What Is the Rationale for the Proposed Standards for Carbon
Monoxide or Hydrocarbons?
H. What Is the Rationale for the Proposed Standard for
Destruction and Removal Efficiency?
XII. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Hydrochloric Acid Production Furnaces?
A. What Is the Rationale for the Proposed Standards for Dioxin
and Furan?
B. What Is the Rationale for the Proposed Standards for Mercury,
Semivolatile Metals, and Low Volatile Metals?
C. What Is the Rationale for the Proposed Standards for Total Chlorine?
D. What Is the Rationale for the Proposed Standards for Carbon
Monoxide or Hydrocarbons?
E. What Is the Rationale for the Proposed Standard for
Destruction and Removal Efficiency?
XIII. What Is the Rationale for Proposing An Alternative Risk-Based
Standard for Total Chlorine in Lieu of the MACT Standard?
A. What Is the Legal Authority to Establish Risk-Based Standards?
B. What Is the Rationale for the National Exposure Standards?
C. How Would You Determine if Your Total Chlorine Emission Rate
Meets the Eligibility Requirements Defined by the National Exposure Standards?
D. What Is the Rationale for Caps on the Risk-Based Emission Limits?
E. What Would Your Risk-Based Eligibility Demonstration Contain?
F. When Would You Complete and Submit Your Eligibility Demonstration?
G. How Would the Risk-Based HCl-Equivalent Emission Rate Limit
Be Implemented?
H. How Would You Ensure that Your Facility Remains Eligible for
the Risk-Based Emission Limit?
I. Request for Comment on an Alternative Approach: Risk-Based
National Emission Standards
XIV. How Did EPA Determine Testing and Monitoring Requirements for
the Proposed Rule?
A. What Is the Rationale for the Proposed Testing Requirements?
B. What Are the Dioxin/Furan Testing Requirements for Boilers
that Would Not Be Subject to a Numerical Dioxin/Furan Emission Standard?
C. What Are the Proposed Test Methods?
D. What Is the Rationale for the Proposed Continuous Monitoring
Requirements?
E. What Are the Averaging Periods for the Operating Parameter
Limits, and How Are Performance Test Data Averaged to Calculate the Limits?
F. How Would Sources Comply with Emissions Standards Based on
Normal Emissions?
G. How Would Sources Comply with Emission Standards Expressed as
Hazardous Waste Thermal Emissions?
H. What Happens if My Thermal Emissions Standard Limits
Emissions to Below the Detection Limit of the Stack Test Methods?
I. Are We Concerned About Possible Negative Biases Associated
With Making Hydrogen Chloride Measurements in High Moisture Conditions?
J. What Are the Other Proposed Compliance Requirements?
XV. How Did EPA Determine Compliance Times for this Proposed Rule?
XVI. How Did EPA Determine the Required Records and Reports for the
Proposed Rule?
A. Summary of Requirements Currently Applicable to Incinerators,
Cement Kilns, and Lightweight Aggregate Kilns and that Would Be
Applicable to Boilers and Hydrochloric Acid Production Furnaces
B. Why Is EPA Proposing Notification of Intent to Comply and
Compliance Progress Report Requirements?
XVII. What Are the Title V and RCRA Permitting Requirements for
Phase I and Phase II Sources?
A. What Is the General Approach to Permitting Hazardous Waste
Combustion Sources?
B. How Will the Replacement Standards Affect Permitting for
Phase I Sources?
C. What Permitting Requirements Is EPA Proposing for Phase II Sources?

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D. How Would this Proposal Affect the RCRA Site-Specific Risk
Assessment Policy?
XVIII. What Alternatives to the Particulate Matter Standard Is EPA
Proposing or Requesting Comment On?
A. What Alternative to the Particulate Matter Standard Is EPA
Proposing for Incinerators, Liquid Fuel-Fired Boilers, and Solid
Fuel-Fired Boilers?
B. What Alternative to the Particulate Matter Standard Is EPA
Requesting Comment On?
XIX. What Are the Proposed RCRA State Authorization and CAA
Delegation Requirements?
A. What Is the Authority for this Rule?
B. Are There Any Changes to the CAA Delegation Requirements for
Phase I Sources?
C. What Are the Proposed CAA Delegation Requirements for Phase
II Sources?

Part Three: Proposed Revisions to Compliance Requirements

I. Why Is EPA Proposing to Allow Phase I Sources to Conduct the
Initial Performance Test to Comply with the Replacement Rules 12
Months After the Compliance Date?
II. Why Is EPA Requesting Comment on Requirements Promulgated as
Interim Standards or as Final Amendments?
A. Interim Standards Amendments to the Startup, Shutdown, and
Malfunction Plan Requirements
B. Interim Standards Amendments to the Compliance Requirements
for Ionizing Wet Scrubbers
C. Why Is EPA Requesting Comment on the Fugitive Emission Requirements?
D. Why Is EPA Requesting Comment on Bag Leak Detector Sensitivity?
E. Final Amendments Waiving Operating Parameter Limits during
Testing without an Approved Test Plan
III. Why Is EPA Requesting Comment on Issues and Amendments that
Were Previously Proposed?
A. Definition of Research, Development, and Demonstration Source
B. Identification of an Organics Residence Time that Is
Independent of, and Shorter than, the Hazardous Waste Residence Time
C. Why Is EPA Not Proposing to Extend APCD Controls after the
Residence Time Has Expired when Sources Operate under Alternative
Section 112 or 129 Standards?
D. Why Is EPA Proposing to Allow Use of Method 23 as an
Alternative to Method 0023A for Dioxin/Furan?
E. Why Is EPA Not Proposing the ``Matching the Profile''
Alternative Approach to Establish Operating Parameter Limits?
F. Why Is EPA Not Proposing to Allow Extrapolation of OPLs?
G. Why Is EPA Proposing to Delete the Limit on Minimum
Combustion Chamber Temperature for Dioxin/Furan for Cement Kilns?
H. Why Is EPA Requesting Additional Comment on Whether to Add a
Maximum pH Limit for Wet Scrubbers to Control Mercury Emissions?
I. How Is EPA Proposing to Ensure Performance of Electrostatic
Precipitators, Ionizing Wet Scrubbers, and Fabric Filters?
IV. Other Proposed Compliance Revisions
A. What Is the Proposed Clarification to the Public Notice
Requirement for Approved Test Plans?
B. What Is the Proposed Clarification to the Public Notice
Requirement for the Petition to Waive a Performance Test?

Part Four: Impacts of the Proposed Rule

I. What Are the Air Impacts?
II. What Are the Water and Solid Waste Impacts?
III. What Are the Energy Impacts?
IV. What are the Control Costs?
V. Can We Achieve the Goals of the Proposed Rule in a Less Costly Manner?
VI. What are the Economic Impacts?
A. Market Exit Estimates
B. Quantity of Waste Reallocated
C. Employment Impacts
VII. What Are the Benefits of Reductions in Particulate Matter Emissions?
VIII. What are the Social Costs and Benefits of the Proposed Rule?
A. Combustion Market Overview
B. Baseline Specification
C. Analytical Methodology and Findings--Social Cost Analysis
D. Analytical Methodology and Findings--Benefits Assessment
IX. How Does the Proposed Rule Meet the RCRA Protectiveness Mandate?
A. Background
B. Assessment of Risks

Part Five: Administrative Requirements

I. Executive Order 12866: Regulatory Planning and Review
II. Paperwork Reduction Act
III. Regulatory Flexibility Act
IV. Unfunded Mandates Reform Act
V. Executive Order 13132: Federalism
VI. Executive Order 13175: Consultation and Coordination with Indian
Tribal Governments
VII. Executive Order 13045: Protection of Children from
Environmental Health and Safety Risks
VIII. Executive Order 13211: Actions that Significantly Affect
Energy Supply, Distribution, or Use
IX. National Technology Transfer and Advancement Act
X. Executive Order 12898: Federal Actions to Address Environmental
Justice in Minority Populations and Low-Income Populations
XI. Congressional Review

Abbreviations and Acronyms Used in This Document

acfm--actual cubic feet per minute
Btu--British thermal units
CAA--Clean Air Act
CFR--Code of Federal Regulations
DRE--destruction and removal efficiency
dscf--dry standard cubic foot
dscm--dry standard cubic meter
EPA--Environmental Protection Agency
FR--Federal Register
gr/dscf--grains per dry standard cubic foot
HAP--hazardous air pollutant(s)
ICR--Information Collection Request
kg/hr--kilograms per hour
kW-hour--kilo Watt hour
MACT--Maximum Achievable Control Technology
mg/dscm--milligrams per dry standard cubic meter
MMBtu--million British thermal unit
ng/dscm--nanograms per dry standard cubic meter
NESHAP--national emission standards for HAP
ng--nanograms
POHC--principal organic hazardous constituent
ppmv--parts per million by volume
ppmw--parts per million by weight
Pub. L.--Public Law
RCRA--Resource Conservation and Recovery Act
SRE--system removal efficiency
TEQ--toxicity equivalence
ug/dscm--micrograms per dry standard cubic meter
U.S.C.--United States Code

Part One: Background and Summary

I. Background Information

A. What Criteria Are Used in the Development of NESHAP?

1. What Information Is Covered in This Preamble and How Is It Organized?
In this preamble, EPA summarizes the important features of these
proposed standards that apply to hazardous waste burning incinerators,
cement kilns, lightweight aggregate kilns, boilers, and hydrochloric
acid production furnaces, known collectively as HWCs. This preamble
describes: (1) The environmental, energy, and economic impacts of these
proposed standards; (2) the basis for each of the decisions made
regarding the proposed standards; (3) requests public comments on
certain issues; and (4) discusses administrative requirements relative
to this action.
2. Where in the Code of Federal Regulations Will These Standards Be Codified?
The Code of Federal Regulations (CFR) is a codification of the
general and permanent rules published in the Federal Register by the
Executive departments and agencies of the Federal Government. The code
is divided into 50 titles that represent broad areas subject to Federal
regulation. These proposed rules would be published in Title 40,
Protection of the Environment, Part 63, Subpart EEE: National Emission
Standards for Hazardous Air Pollutants From Hazardous Waste Combustors.

[[Page 21202]]

3. What Criteria Are Used in the Development of NESHAP?
Section 112 of the Clean Air Act (CAA) requires EPA to promulgate
regulations for the control of HAP emissions from each source category
listed by EPA under section 112(c). The statute requires the
regulations to reflect the maximum degree of reduction in emissions of
HAP that is achievable taking into consideration the cost of achieving
the emission reduction, any nonair quality health and environmental
impacts, and energy requirements. This level of control is commonly
referred to as MACT (i.e., maximum achievable control technology). The
MACT regulation can be based on the emission reductions achievable
through application of measures, processes, methods, systems, or
techniques including, but not limited to: (1) Reducing the volume of,
or eliminating emissions of, such pollutants through process changes,
substitutions of materials, or other modifications; (2) enclosing
systems or processes to eliminate emissions; (3) collecting, capturing,
or treating such pollutants when released from a process, stack,
storage or fugitive emission point; (4) design, equipment, work
practices, or operational standards as provided in subsection 112(h);
or (5) a combination of the above. See section 112(d)(2) of the CAA.
For new sources, MACT standards cannot be less stringent than the
emission control achieved in practice by the best-controlled similar
source. See section 112(d)(3) of the Act. The MACT standards for
existing sources can be less stringent than standards for new sources,
but they cannot be less stringent than the average emission limitation
achieved by the best-performing 12 percent of existing sources for
categories and subcategories with 30 or more sources, or the best-
performing 5 sources for categories or subcategories with fewer than 30
sources. Id. This level of control is usually referred to as the MACT
``floor'', the term used in the Legislative History.
In essence, MACT standards ensure that all major sources of air
toxic (i.e., HAP) emissions achieve the level of control already being
achieved by the better-controlled and lower-emitting sources in each
category. This approach provides assurance to citizens that each major
source of toxic air pollution will be required to effectively control
its emissions of air toxics. At the same time, this approach provides a
level playing field, ensuring that facilities that employ cleaner
processes and good emission controls are not disadvantaged relative to
competitors with poorer controls.

B. What Is the Regulatory Development Background of the Source
Categories in the Proposed Rule?

Today's notice proposes standards for controlling emissions of HAP
from hazardous waste combustors. Hazardous waste combustors comprise
several categories of sources that burn hazardous waste: incinerators,
cement kilns, lightweight aggregate kilns, boilers and hydrochloric
acid production furnaces. We call incinerators, cement kilns, and
lightweight aggregate kilns Phase I sources because we have already
promulgated standards for those source categories. We call boilers and
hydrochloric acid production furnaces Phase II sources because we
intended to promulgate MACT standards for those source categories after
promulgating MACT standards for Phase I sources. The regulatory
background of Phase I and Phase II source categories is discussed below.
1. Phase I Source Categories
Phase I combustor sources are regulated under the Resource
Conservation and Recovery Act (RCRA), which establishes a ``cradle-to-
grave'' regulatory structure overseeing the safe treatment, storage,
and disposal of hazardous waste. We issued RCRA rules to control air
emissions from incinerators in 1981, 40 CFR parts 264 and 265, subpart
O, and from cement kilns and lightweight aggregate kilns that burn
hazardous waste in 1991, 40 CFR part 266, subpart H. These rules rely
generally on risk-based standards to achieve the RCRA protectiveness mandate.
The Phase I source categories are also subject to standards under
section 112(d) of the Clean Air Act. We promulgated standards for Phase
I sources on September 30, 1999 (64 FR 52828). This final rule is
referred to as the Phase I rule or 1999 final rule. These emission
standards created a technology-based national cap for hazardous air
pollutant emissions from the combustion of hazardous waste in these
devices. The rule regulates emissions of numerous hazardous air
pollutants: dioxin/furans, other toxic organics (through surrogates),
mercury, other toxic metals (both directly and through a surrogate),
and hydrogen chloride and chlorine gas. Where necessary, section
3005(c)(3) of RCRA provides the authority to impose additional
conditions in a RCRA permit to protect human health and the environment.
A number of parties, representing interests of both industrial
sources and of the environmental community, sought judicial review of
the Phase I rule. On July 24, 2001, the United States Court of Appeals
for the District of Columbia Circuit (the Court) granted portions of
the Sierra Club's petition for review and vacated the challenged
portions of the standards. Cement Kiln Recycling Coalition v. EPA, 255
F. 3d 855 (D.C. Cir. 2001). The Court held that EPA had not
demonstrated that its calculation of MACT floors met the statutory
requirement of being no less stringent than (1) the average emission
limitation achieved by the best performing 12 percent of existing
sources and (2) the emission control achieved in practice by the best
controlled similar source for new sources. 255 F.3d at 861, 865-66. As
a remedy, the Court, after declining to rule on most of the issues
presented in the industry petitions for review, vacated the
``challenged regulations,'' stating that: ``[W]e have chosen not to
reach the bulk of industry petitioners' claims, and leaving the
regulations in place during remand would ignore petitioners'
potentially meritorious challenges.'' Id. at 872. Examples of the
specific challenges the Court indicated might have merit were
provisions relating to compliance during start up/shut down and
malfunction events, including emergency safety vent openings, the
dioxin/furan standard for lightweight aggregate kilns, and the
semivolatile metal standard for cement kilns. Id. However, the Court
stated, ``[b]ecause this decision leaves EPA without standards
regulating [hazardous waste combustor] emissions, EPA (or any of the
parties to this proceeding) may file a motion to delay issuance of the
mandate to request either that the current standards remain in place or
that EPA be allowed reasonable time to develop interim standards.'' Id.
Acting on this invitation, all parties moved the Court jointly to
stay the issuance of its mandate for four months to allow EPA time to
develop interim standards, which would replace the vacated standards
temporarily, until final standards consistent with the Court's mandate
are promulgated. The interim standards were published on February 13,
2002 (67 FR 6792). EPA did not justify or characterize these standards
as conforming to MACT, but rather as an interim measure to prevent the
adverse environmental and other consequences that would result from the
regulatory gap resulting from no standards being in place. Id. at 6795-96.
The motion also indicates that EPA will issue final standards which
comply

[[Page 21203]]

with the Court's opinion by June 14, 2005, and it indicates that EPA
and Petitioner Sierra Club intend to enter into a settlement agreement
requiring us to promulgate final rules by that date, and that date be
judicially enforceable. EPA and Sierra Club entered into that
settlement agreement on March 4, 2002.
The joint motion also details other actions we agreed to take,
including issuing a one-year extension to the September 30, 2002,
compliance date (66 FR 63313, December 6, 2001), and promulgating
several of the compliance and implementation amendments to the rule
which we proposed on July 3, 2001 (66 FR 35126). These final amendments
were published on February 14, 2002 (67 FR 6968).
2. Phase II Source Categories
Phase II combustors--boilers and hydrochloric acid production
furnaces--are also regulated under the Resource Conservation and
Recovery Act (RCRA) pursuant to 40 CFR part 266, subpart H, and (for
reasons discussed below) are also subject to the MACT standard setting
process in section 112(d) of the CAA. We delayed promulgating MACT
standards for these source categories pending reevaluation of the MACT
standard setting methodology following the Court's decision to vacate
the standards for the Phase I source categories. We have also entered
into a judicially enforceable consent decree with Sierra Club which
requires EPA to promulgate MACT standards for the Phase II sources by
June 14, 2005--the same date that (for independent reasons) is required
for the replacement standards for Phase I sources.

C. What Is the Statutory Authority for This Standard?

Section 112 of the Clean Air Act requires that the EPA promulgate
regulations requiring the control of HAP emissions from major and
certain area sources. The control of HAP is achieved through
promulgation of emission standards under sections 112(d) and (in a
second round of standard setting) (f) and, in appropriate
circumstances, work practice standards under section 112(h).
EPA's initial list of categories of major and area sources of HAP
selected for regulation in accordance with section 112(c) of the Act
was published in the Federal Register on July 16, 1992 (57 FR 31576).
Incinerators, cement kilns, lightweight aggregate kilns, industrial/
commercial/institutional boilers and process heaters, and hydrochloric
acid production furnaces are among the listed 174 categories of
sources. The listing was based on the Administrator's determination
that they may reasonably be anticipated to emit several of the 188
listed HAP in quantities sufficient to designate them as major sources.

D. What Is the Relationship Between the Proposed Rule and Other MACT
Combustion Rules?

The proposed amendments to the subpart EEE, part 63, standards for
hazardous waste combustors would apply to the source categories that
are currently subject to that subpart--incinerators, cement kilns, and
lightweight aggregate kilns that burn hazardous waste. Today's proposed
rule, however, would also amend subpart EEE to establish MACT standards
for the Phase II source categories--those boilers and hydrochloric acid
production furnaces that burn hazardous waste.
Generally speaking, you are an affected source pursuant to subpart
EEE if you combust, or have previously combusted, hazardous waste in an
incinerator, cement kiln, lightweight aggregate kiln, boiler, or
hydrochloric acid production furnace. You continue to be an affected
source until you cease burning hazardous waste and initiate closure
requirements pursuant to RCRA. See Sec. 63.1200(b). If you never
previously combusted hazardous waste, or have ceased burning hazardous
waste and initiated RCRA closure requirements, you are not subject to
subpart EEE. Rather, EPA has promulgated or proposed separate MACT
standards for sources that do not burn hazardous waste within the
following source categories: commercial and industrial solid waste
incinerators (40 CFR part 60, subparts CCCC and DDDD); Portland cement
manufacturing facilities (40 CFR part 63, subpart LLL); industrial/
commercial/institutional boilers and process heaters (40 CFR part 63,
proposed subpart DDDDD); and hydrochloric acid production facilities
(40 CFR part 63, subpart NNNNN). In addition, EPA considered whether to
establish MACT standards for lightweight aggregate manufacturing
facilities that do not burn hazardous waste, and determined that they
are not major sources of HAP emissions. Thus, EPA has not established
MACT standards for lightweight aggregate manufacturing facilities that
do not burn hazardous waste.
Note that non-stack emissions points are not regulated under
subpart EEE.\1\ Emissions attributable to storage and handling of
hazardous waste prior to combustion (i.e., emissions from tanks,
containers, equipment, and process vents) would continue to be
regulated pursuant to either RCRA subpart AA, BB, and CC or an
applicable MACT that applies to the before-mentioned material handling
devices. Emissions unrelated to the hazardous waste operations may be
regulated pursuant to other MACT rulemakings. For example, Portland
cement manufacturing facilities that combust hazardous waste are
subject to both subpart EEE and subpart LLL, and hydrochloric acid
production facilities that combust hazardous waste may be subject to
both subpart EEE and subpart NNNNN.\2\ In these instances subpart EEE
controls HAP emissions from the cement kiln and hydrochloric acid
production furnace stack, while subparts LLL and NNNNN would control
HAP emissions from other operations that are not directly related to
the combustion of hazardous waste (e.g., clinker cooler emissions for
cement production facilities, and hydrochloric acid product
transportation and storage for hydrochloric acid production facilities).
---------------------------------------------------------------------------

\1\ Note, however, that fugitive emissions attributable to the
combustion of hazardous waste from the combustion device are
regulated pursuant to subpart EEE.
\2\ Hydrochloric acid production furnaces that combust hazardous
waste would also be affected sources subject to subpart NNNNN if
they produce a liquid acid product that contains greater than 30%
hydrochloric acid.
---------------------------------------------------------------------------

Note that if you temporarily cease burning hazardous waste for any
reason, you remain an affected source and are still subject to the
applicable Subpart EEE requirements. However, even as an affected
source, the proposed emission standards or operating limits derived
from the hazardous waste combustors do not apply if: (1) Hazardous
waste is not in the combustion chamber and you elect to comply with
other MACT (or CAA section 129) standards that otherwise would be
applicable if you were not burning hazardous waste, e.g., the
nonhazardous waste burning Portland Cement Kiln MACT (subpart LLL); or
(2) you are in a startup, shutdown, or malfunction mode of operation.

E. What Are the Health Effects Associated With Pollutants Emitted by
Hazardous Waste Combustors?

Today's proposed rule protects air quality and promotes the public
health by reducing the emissions of some of the HAP listed in section
112(b)(1) of the CAA. Emissions data collected in the development of
this proposed rule show that metals, particulate matter, hydrogen
chloride and chlorine gas, dioxins and furans, and other organic
compounds are emitted from hazardous waste combustors. The HAP that would

[[Page 21204]]

be controlled with this rule are associated with a variety of adverse
health affects. These adverse health effects include chronic health
disorders (e.g., irritation of the lung, skin, and mucus membranes and
effects on the blood, digestive tract, kidneys, and central nervous
system), and acute health disorders (e.g., lung irritation and
congestion, alimentary effects such as nausea and vomiting, and effects
on the central nervous system). Provided below are brief descriptions
of risks associated with HAP that are emitted from hazardous waste
combustors. Note that a more detailed discussion of the risks
associated with these emissions is included in Part Four.
Antimony
Antimony occurs at very low levels in the environment, both in the
soils and foods. Higher concentrations, however, are found at antimony
processing sites, and in their hazardous wastes. The most common
industrial use of antimony is as a fire retardant in the form of
antimony trioxide. Chronic occupational exposure to antimony (generally
antimony trioxide) is most commonly associated with ``antimony
pneumoconiosis,'' a condition involving fibrosis and scarring of the
lung tissues. Studies have shown that antimony accumulates in the lung
and is retained for long periods of time. Effects are not limited to
the lungs, however, and myocardial effects (effects on the heart
muscle) and related effects (e.g., increased blood pressure, altered
EKG readings) are among the best-characterized human health effects
associated with antimony exposure. Reproductive effects (increased
incidence of spontaneous abortions and higher rates of premature
deliveries) have been observed in female workers exposed in antimony
processing facilities. Similar effects on the heart, lungs, and
reproductive system have been observed in laboratory animals.
EPA recently assessed the carcinogenicity of antimony and found the
evidence for carcinogenicity to be weak, with conflicting evidence from
inhalation studies with laboratory animals, equivocal data from the
occupational studies, negative results from studies of oral exposures
in laboratory animals, and little evidence of mutagenicity or
genotoxicity.\3\ As a consequence, EPA concluded that insufficient data
are available to adequately characterize the carcinogenicity of
antimony and, accordingly, the carcinogenicity of antimony cannot be
determined based on available information. However, IARC (International
Agency for Research on Cancer) in an earlier evaluation, concluded that
antimony trioxide is ``possibly carcinogenic to humans'' (Group 2B).
---------------------------------------------------------------------------

\3\ See ``Evaluating the Carcinogenicity of Antimony,'' Risk
Assessment Issue Paper (98-030/07-26-99), Superfund Technical
Support Center, National Center for Environmental Assessment, July
26, 1999.
---------------------------------------------------------------------------

Arsenic
Acute (short-term) high-level inhalation exposure to arsenic dust
or fumes has resulted in gastrointestinal effects (nausea, diarrhea,
abdominal pain), and central and peripheral nervous system disorders.
Chronic (long-term) inhalation exposure to inorganic arsenic in humans
is associated with irritation of the skin and mucous membranes. Human
data suggest a relationship between inhalation exposure of women
working at or living near metal smelters and an increased risk of
reproductive effects, such as spontaneous abortions. Inorganic arsenic
exposure in humans by the inhalation route has been shown to be
strongly associated with lung cancer, while ingestion or inorganic
arsenic in humans has been linked to a form of skin cancer and also to
bladder, liver, and lung cancer. EPA has classified inorganic arsenic
as a Group A, human carcinogen.
Beryllium
Beryllium is a hard, grayish metal naturally found in minerals,
rocks, coal, soil, and volcanic dust. Beryllium dust enters the air
from burning coal and oil. This beryllium dust will eventually settle
over the land and water. It enters water from erosion of rocks and
soil, and from industrial waste. Some beryllium compounds will dissolve
in water, but most stick to particles and settle to the bottom. Most
beryllium in soil does not dissolve in water and remains bound to soil.
Beryllium does not accumulate in the food chain.
Beryllium can be harmful if you breathe it. The effects depend on
how much you are exposed to and for how long. If beryllium air levels
are high enough, an acute condition can result. This condition
resembles pneumonia and is called acute beryllium disease. Long-term
exposure to beryllium can increase the risk of developing lung cancer.
Cadmium
The acute (short-term) effects of cadmium inhalation in humans
consist mainly of effects on the lung, such as pulmonary irritation.
Chronic (long-term) inhalation or oral exposure to cadmium leads to a
build-up of cadmium in the kidneys that can cause kidney disease.
Cadmium has been shown to be a developmental toxicant in animals,
resulting in fetal malformations and other effects, but no conclusive
evidence exists in humans. An association between cadmium exposure and
an increased risk of lung cancer has been reported from human studies,
but these studies are inconclusive due to confounding factors. Animal
studies have demonstrated an increase in lung cancer from long-term
inhalation exposure to cadmium. EPA has classified cadmium as a Group
B1, probable carcinogen.
Chlorine Gas
Acute exposure to high levels of chlorine in humans can result in
chest pain, vomiting, toxic pneumonitis, and pulmonary edema. At lower
levels chlorine is a potent irritant to the eyes, the upper respiratory
tract, and lungs. Chronic exposure to chlorine gas in workers has
resulted in respiratory effects including eye and throat irritation and
airflow obstruction. Animal studies have reported decreased body weight
gain, eye and nose irritation, nonneoplastic nasal lesions, and
respiratory epithelial hyperplasia from chronic inhalation exposure to
chlorine. No information is available on the carcinogenic effects of
chlorine in humans from inhalation exposure. We have not classified
chlorine for potential carcinogenicity.
Chromium
Chromium may be emitted in two forms, trivalent chromium (chromium
III) or hexavalent chromium (chromium VI). The respiratory tract is the
major target organ for chromium VI toxicity, for acute (short-term) and
chronic (long-term) inhalation exposures. Shortness of breath,
coughing, and wheezing have been reported from acute exposure to
chromium VI, while perforations and ulcerations of the septum,
bronchitis, decreased pulmonary function, pneumonia, and other
respiratory effects have been noted from chronic exposure. Limited
human studies suggest that chromium VI inhalation exposure may be
associated with complications during pregnancy and childbirth, while
animal studies have not reported reproductive effects from inhalation
exposure to chromium VI. Human and animal studies have clearly
established that inhaled chromium VI is a carcinogen, resulting in an
increased risk of lung cancer. EPA has classified chromium VI as a
Group A, human carcinogen.
Chromium III is less toxic than chromium VI. The respiratory tract
is also the major target organ for

[[Page 21205]]

chromium III toxicity, similar to chromium VI. Chromium III is an
essential element in humans, with a daily intake of 50 to 200
micrograms per day recommended for an adult. The body can detoxify some
amount of chromium VI to chromium III. EPA has not classified chromium
III with respect to carcinogenicity.
Cobalt
Cobalt is a relatively rare metal that is produced primarily as a
by-product during refining of other metals, primarily copper. Cobalt
has been widely reported to cause respiratory effects in humans exposed
by inhalation, including respiratory irritation, wheezing, asthma, and
pneumonia. Cardiomyopathy (or damage to the heart muscle) has also been
reported, although this effect is better known from oral exposure.
Other effects of oral exposure in humans are polycythemia (an
abnormally high number of red blood cells) and the blocking of uptake
of iodine by the thyroid. In addition, cobalt is a sensitizer in humans
by any route of exposure. Sensitized individuals may react to
inhalation of cobalt by developing asthma or to ingestion or dermal
contact with cobalt by developing dermatitis. Cobalt is a vital
component of vitamin B12, though there is no evidence that
intake of cobalt is ever limiting in the human diet.
A number of epidemiological studies have found that exposures to
cobalt are associated with an increased incidence of lung cancer in
occupational settings. The International Agency for Research on Cancer
(IARC, part of the World Health Organization) classifies cobalt and
cobalt compounds as ``possibly carcinogenic to humans'' (Group 2B). The
American Conference of Governmental Industrial Hygienists (ACGIH) has
classified cobalt as a confirmed animal carcinogen with unknown
relevance to humans (category A3). An EPA assessment concludes that
under EPA's 1986 guidelines, cobalt would be classified as a probable
human carcinogen (group B1) based on limited evidence of
carcinogenicity in humans and sufficient evidence of carcinogenicity in
animals, as evidenced by an increased incidence of alveolar/bronchiolar
tumors in recent studies of both rats and mice. Under EPA's proposed
cancer guidelines, cobalt is considered likely to be carcinogenic to
humans.\4\
---------------------------------------------------------------------------

\4\ See ``Derivation of a Provisional Carcinogenicity Assessment
for Cobalt and Compounds,'' Risk Assessment Issue Paper (00-122/1-
15-02), Superfund Technical Support Center, National Center for
Environmental Assessment, January 15, 2002.
---------------------------------------------------------------------------

Dioxins and Furans
Exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) at
levels 10 times or less above those modeled to approximate average
background exposure have resulted in adverse non-cancer health effects
in animals. These effects include changes in hormone systems,
alterations in fetal development, reduced reproductive capacity, and
immunosuppression. Effects that may be linked to dioxin and furan
exposures at low dose in humans include changes in markers of early
development and hormone levels. Dioxin and furan exposures are
associated with altered liver function and lipid metabolism changes in
activity of various liver enzymes, depression of the immune system, and
endocrine and nervous system effects. EPA in its 1985 dioxin assessment
classified 2,3,7,8-TCDD as a probable human carcinogen. The
International Agency for Research on Cancer (IARC) concluded in 1997
that the overall weight of the evidence was sufficient to characterize
2,3,7,8-TCDD as a known human carcinogen.\5\ In 2001 the U.S.
Department of Health and Human Services National Toxicology Program in
their 9th Report on Carcinogens classified 2,3,7,8-TCDD as a known
human carcinogen.\6\
---------------------------------------------------------------------------

\5\ IARC (International Agency for Research on Cancer). (1997)
IARC monographs on the evaluation of carcinogenic risks to humans.
Vol. 69. Polychlorinated dibenzo-para-dioxins and polychlorinated
dibenzofurans. Lyon, France.
\6\ The U.S. Department of Health and Human Services, National
Toxicology Program 9th Report on Carcinogens, Revised January 2001.
---------------------------------------------------------------------------

Hydrogen Chloride/Hydrochloric Acid
Hydrogen chloride, also called hydrochloric acid, is corrosive to
the eyes, skin, and mucous membranes. Acute (short-term) inhalation
exposure may cause eye, nose, and respiratory tract irritation and
inflammation and pulmonary edema in humans. Chronic (long-term)
occupational exposure to hydrochloric acid has been reported to cause
gastritis, bronchitis, and dermatitis in workers. Prolonged exposure to
low concentrations may also cause dental discoloration and erosion. No
information is available on the reproductive or developmental effects
of hydrochloric acid in humans. In rats exposed to hydrochloric acid by
inhalation, altered estrus cycles have been reported in females and
increased fetal mortality and decreased fetal weight have been reported
in offspring. EPA has not classified hydrochloric acid for carcinogenicity.
Lead
Lead is a very toxic element, causing a variety of effects at low
dose levels. Brain damage, kidney damage, and gastrointestinal distress
may occur from acute (short-term) exposure to high levels of lead in
humans. Chronic (long-term) exposure to lead in humans results in
effects on the blood, central nervous system (CNS), blood pressure, and
kidneys. Children are particularly sensitive to the chronic effects of
lead, with slowed cognitive development, reduced growth and other
effects reported. Reproductive effects, such as decreased sperm count
in men and spontaneous abortions in women, have been associated with
lead exposure. The developing fetus is at particular risk from maternal
lead exposure, with low birth weight and slowed postnatal
neurobehavioral development noted. Human studies are inconclusive
regarding lead exposure and cancer, while animal studies have reported
an increase in kidney cancer from lead exposure by the oral route. EPA
has classified lead as a Group B2, probable human carcinogen.
Manganese
Health effects in humans have been associated with both
deficiencies and excess intakes of manganese. Chronic (long-term)
exposure to low levels of manganese in the diet is considered to be
nutritionally essential in humans, with a recommended daily allowance
of 2 to 5 milligrams per day (mg/d). Chronic exposure to high levels of
manganese by inhalation in humans results primarily in central nervous
system (CNS) effects. Visual reaction time, hand steadiness, and eye-
hand coordination were affected in chronically-exposed workers.
Manganism, characterized by feelings of weakness and lethargy, tremors,
a mask-like face, and psychological disturbances, may result from
chronic exposure to higher levels. Impotence and loss of libido have
been noted in male workers afflicted with manganism attributed to
inhalation exposures. EPA has classified manganese in Group D, not
classifiable as to carcinogenicity in humans.
Mercury
Mercury exists in three forms: elemental mercury, inorganic mercury
compounds (primarily mercuric chloride), and organic mercury compounds
(primarily methyl mercury). Each form exhibits different health
effects. Various sources may release elemental or inorganic mercury;
environmental methyl mercury is

[[Page 21206]]

typically formed by biological processes after mercury has precipitated
from the air.
Acute (short-term) exposure to high levels of elemental mercury in
humans results in central nervous system (CNS) effects such as tremors,
mood changes, and slowed sensory and motor nerve function. High
inhalation exposures can also cause kidney damage and effects on the
gastrointestinal tract and respiratory system. Chronic (long-term)
exposure to elemental mercury in humans also affects the CNS, with
effects such as increased excitability, irritability, excessive
shyness, and tremors. EPA has not classified elemental mercury with
respect to cancer.
Acute exposure to inorganic mercury by the oral route may result in
effects such as nausea, vomiting, and severe abdominal pain. The major
effect from chronic exposure to inorganic mercury is kidney damage.
Reproductive and developmental animal studies have reported effects
such as alterations in testicular tissue, increased embryo resorption
rates, and abnormalities of development. Mercuric chloride (an
inorganic mercury compound) exposure has been shown to result in
forestomach, thyroid, and renal tumors in experimental animals. EPA has
classified mercuric chloride as a Group C, possible human carcinogen.
Nickel
Nickel is a commonly used industrial metal, and is frequently
associated with iron and copper ores. Contact dermatitis is the most
common effect in humans from exposure to nickel, whether via
inhalation, oral, or dermal exposure. Cases of nickel-contact
dermatitis have been reported following occupational and non-
occupational exposure, with symptoms of itching of the fingers, wrists,
and forearms. Many studies have also demonstrated dermal effects in
sensitive humans from ingested nickel, invoking an eruption or
worsening of eczema. Chronic inhalation exposure to nickel in humans
results in direct respiratory effects, such as asthma due to primary
irritation, or an allergic response and an increased risk of chronic
respiratory tract infections.
Animal studies have reported a variety of inflammatory effects on
the lungs, as well as effects on the kidneys and immune system from
inhalation exposure to nickel. Significant differences in inhalation
toxicity among the various forms of nickel have been documented, with
soluble nickel compounds being more toxic to the respiratory tract than
less soluble compounds (e.g., nickel oxide). Animal studies have also
reported effects on the respiratory and gastrointestinal systems,
heart, blood, liver, kidney, and body weight from oral exposure to
nickel, as well as to the fetus.
EPA currently classifies nickel refinery dust and nickel subsulfide
(a major component of nickel refinery dust) as class A human
carcinogens based on increased risks of lung and nasal cancer in human
epidemiological studies of occupational exposures to nickel refinery
dust, increased tumor incidences in animals by several routes of
administration in several animal species, and positive results in
genotoxicity assays. More recently, a pair of inhalation studies
performed under the auspices of the National Toxicology Program (NTP)
of the National Institutes of Health concluded that there was no
evidence of carcinogenic activity of soluble nickel salts in rats or
mice and that there was some evidence of carcinogenic activity of
nickel oxide in male and female rats based on increased incidence of
alveolar/bronchiolar adenoma or carcinoma and increased incidence of
benign or malignant pheochromocytoma (a tumor of the adrenal gland) and
equivocal evidence in mice based on marginally increased incidence of
alveolar/bronchiolar adenoma or carcinoma in females and no evidence in
males. The Tenth Annual Report on Carcinogens classifies nickel
compounds as ``known to be human carcinogens.'' \7\ This is consistent
with the International Agency for Cancer Research (IARC) which
classifies nickel compounds as Group 1 human carcinogens.
---------------------------------------------------------------------------

\7\ Report on Carcinogens, Tenth Edition; U.S. Department of
Health and Human Services, Public Health Service, National
Toxicology Program, December 2002.
---------------------------------------------------------------------------

Organic HAP
Organic HAPs include halogenated and nonhalogenated organic classes
of compounds such as polycyclic aromatic hydrocarbons (PAHs) and
polychlorinated biphenyls (PCBs). Both PAHs and PCBs are classified as
potential human carcinogens, and are considered toxic, persistent and
bioaccumulative. They include compounds such as benzene, methane,
propane, chlorinated alkanes and alkenes, phenols and chlorinated
aromatics. Adverse health effects of HAPs include damage to the immune
system, as well as neurological, reproductive, developmental,
respiratory and other health problems.
Particulate Matter \8\
---------------------------------------------------------------------------

\8\ The discussion of PM effects is drawn from the executive
summary of the ``Fourth External Review Draft of Air Quality
Criteria for Particulate Matter,'' National Center for Environmental
Assessment, Office of Research and Development, U.S. Environmental
Protection Agency, EPA/600/P-99/002aD, June, 2003.
---------------------------------------------------------------------------

Atmospheric PM is composed of sulfate, nitrate, ammonium, and other
ions, elemental carbon, particle-bound water, a wide variety of organic
compounds, and a large number of elements contained in various
compounds, some of which originate from crustal materials and others
from combustion sources. Combustion sources are the primary origin of
trace metals found in fine particles in the atmosphere. Ambient PM can
be of primary or secondary origin.\9\
---------------------------------------------------------------------------

\9\ Secondary PM is not emitted directly but is formed in the
atmosphere by gas phase or aqueous phase reactions of emissions of
various precursor compounds.
---------------------------------------------------------------------------

[[Page 21207]]

wet and dry deposition.\10\ Acidification of surface waters can have
long-term adverse effects on aquatic ecosystems, including effects on
fish populations, macro invertebrates, species richness, and
zooplankton abundance. In the soil environment, acid deposition has the
potential to inhibit nutrient uptake, alter the ecological processes of
energy flow and nutrient cycling, change ecosystem structure, and
affect ecosystem biodiversity. In addition, ambient fine particles are
well known as the major cause of visibility impairment. Visibility
impairment (or haziness) is widespread in the U.S. and is greatest in
the eastern United States and southern California. In addition, PM
exerts important effects on materials, such as soiling, corrosion, and
degradation of surfaces, and accelerates weathering of man-made and
natural materials.
---------------------------------------------------------------------------

\10\ Nitrates and sulfates in PM are derived primarily from
emissions of SOX and NOX.
---------------------------------------------------------------------------

A large body of evidence exists from epidemiological studies that
demonstrates a relationship between ambient particulate matter (PM) and
mortality and morbidity in the general population and, when combined
with evidence from other studies (e.g., clinical and animal studies),
indicates that exposure to PM is a probable contributing cause to the
adverse human health effects that have been observed. For example, many
different studies report that increased cardiovascular and respiratory-
related mortality risks are significantly associated with various
measures (both long-term and short-term) of ambient PM. Some studies
suggest that a portion of the increased mortality may be associated
with concurrent exposures to PM and other criteria pollutants, such as
SO2. Much evidence exists of positive associations between
ambient PM concentrations and increased respiratory-related hospital
admissions, emergency room, and other medical visits. Additional
findings implicate PM as likely associated with an increased occurrence
of chronic bronchitis and a contributing factor in the exacerbation of
asthmatic conditions. Recent reports from prospective cohort studies of
long-term ambient PM exposures provide substantial evidence of an
association between increased risk of lung cancer and PM, especially
exposure to fine PM or its components.
PM has other effects, beyond the health effects to human beings.
The major effect of atmospheric PM on ecosystems is indirect and occurs
through the deposition of nitrates and sulfates and the acidifying
effects of the associated hydrogen ions contained in wet and dry
deposition.\11\ Acidification of surface waters can have long-term
adverse effects on aquatic ecosystems, including effects on fish
populations, macro invertebrates, species richness, and zooplankton
abundance. In the soil environment, acid deposition has the potential
to inhibit nutrient uptake, alter the ecological processes of energy
flow and nutrient cycling, change ecosystem structure, and affect
ecosystem biodiversity. In addition, ambient fine particles are well
known as the major cause of visibility impairment. Visibility
impairment (or haziness) is widespread in the U.S. and is greatest in
the eastern United States and southern California. In addition, PM
exerts important effects on materials, such as soiling, corrosion, and
degradation of surfaces, and accelerates weathering of man-made and
natural materials.
---------------------------------------------------------------------------

\11\ Nitrates and sulfates in PM are derived primarily from
emissions of SOX and NOX.
---------------------------------------------------------------------------

Selenium
Selenium occurs naturally in soils, is associated with copper
refining, and several industrial processes, and has been used in
pesticides. It is an essential element and bioaccumulates in certain
plant species, and has been associated with toxic effects in livestock
(blind staggers syndrome). Soils containing high levels of selenium
(seleniferous soils can lead to high concentration of selenium in
certain plants, and pose a hazard to livestock and other species.
Bioaccumulation and magnification of selenium has also been observed in
aquatic organisms and has been shown to be toxic to piscivorous fish.
In humans, selenium partitions to the kidneys and liver, and is
excreted through the urine and feces. Selenium intoxication in humans
causes a syndrome known as selenosis. The condition is characterized by
chronic dermatitis, fatigue, anorexia, gastroenteritis, hepatic
degeneration, enlarged spleen and increased concentrations of Se in the
hair and nails. Clinical signs of selenosis include a characteristic
``garlic odor'' of excess selenium excretion in the breath and urine,
thickened and brittle nails, hair and nail loss, lowered hemoglobin
levels, mottled teeth, skin lesions and CNS abnormalities (peripheral
anesthesia, acroparesthesia and pain in the extremities). Aquatic birds
are extremely sensitive to selenium; toxic effects include
teratogenesis. Based on available data, both aquatic birds and aquatic
mammals are sensitive ecological receptors.

II. Summary of the Proposed Rule

A. What Source Categories Are Affected by the Proposed Rule?

1. Incinerators That Burn Hazardous Waste
A hazardous waste burning incinerator is defined under Sec.
63.1201(a) as a device that meets the definition of an incinerator in
40 CFR part 260.10 and that burns hazardous waste at any time.
Hazardous waste incinerators are currently subject to the emission
standards of part 63, subpart EEE.\12\ Hazardous waste incinerator
design types include rotary kilns, liquid injection incinerators,
fluidized bed incinerators, and fixed hearth incinerators. Most
incinerators have air pollution control equipment to capture
particulate matter (and nonvolatile metals) and scrubbing equipment for
the capture of acid gases. At least four incinerators are equipped with
activated carbon injection systems or carbon beds to control dioxin/
furan emissions (as well as other HAP emissions).
---------------------------------------------------------------------------

\12\ Incinerators that burn hazardous waste will also remain
subject to the RCRA hazardous waste incinerator emission limitations
pursuant to Sec. 264 subpart O until they demonstrate compliance
with the interim MACT standards and remove the emission limitations
from their RCRA permit. See Sec. 270.42 appendix I, section a.8 and
introductory paragraph to Sec. 270.62.
---------------------------------------------------------------------------

Incinerators can be further classified as either commercial or
onsite. Commercial incinerators accept and treat, for a tipping fee,
wastes that have been generated off-site. The purpose of commercial
incinerators is to generate profit from treating hazardous wastes. On-
site facilities treat only wastes that have been generated at the
facility to avoid the costs of off-site treatment. In 2003, there were
approximately 107 hazardous waste incinerators in operation, 15 of
which were commercial facilities, the remaining being on-site facilities.
2. Cement Kilns That Burn Hazardous Waste
A hazardous waste burning cement kiln is defined under Sec.
63.1201(a). Cement kilns that burn hazardous waste are currently
subject to the emission standards of part 63, subpart EEE.\13\ Cement
kilns are long, cylindrical, slightly inclined rotating furnaces that
are lined with refractory brick to protect the steel shell and retain
heat within the

[[Page 21208]]

kiln. Cement kilns are designed to calcine, or expel carbon dioxide by
roasting, a blend of raw materials such as limestone, shale, clay, or
sand to produce Portland cement. The raw materials enter the kiln at
the elevated end, and the combustion fuels generally are introduced
into the lower end of the kiln where the clinker product is discharged.
The materials are continuously and slowly moved to the lower end by
rotation of the kiln. As they move down the kiln, the raw materials are
changed to cementitious minerals as a result of increased temperatures
within the kiln.
---------------------------------------------------------------------------

\13\ Cement kilns that burn hazardous waste will also remain
subject to the RCRA Boilers and Industrial Furnace emission
limitations pursuant to Sec. 266 subpart H until they demonstrate
compliance with the interim MACT standards and remove the emission
limitations from their RCRA permit. See Sec. 270.42 appendix I,
section a.8 and introductory paragraph to Sec. 270.66.
---------------------------------------------------------------------------

Portland cement is a fine powder, usually gray in color, that
consists of a mixture of minerals comprising primarily calcium
silicates, aluminates, and aluminoferrites, to which small amounts of
gypsum have been added during the finish grinding operations. Portland
cement is the key ingredient in Portland cement concrete, which is used
in almost all construction applications.
Cement kilns covered by this proposal burn hazardous waste-derived
fuels to replace some or all of normal fossil fuels, typically coal.
Most kilns burn liquid waste; however, cement kilns also may burn
solids and small containers containing viscous or solid hazardous waste
fuels. The annual hazardous waste fuel replacement rate varies
considerably across sources from approximately 25 to 85 percent.
In 2003, there were 14 Portland cement plants in nine states
operating a total of 25 hazardous waste burning kilns. All cement kilns
use either bag houses or electrostatic precipitators to control
particulate matter emissions.
3. Lightweight Aggregate Kilns That Burn Hazardous Waste
A hazardous waste burning lightweight aggregate kiln is defined
under Sec. 63.1201(a). Lightweight aggregate kilns that burn hazardous
waste are currently subject to the emission standards of part 63,
subpart EEE.\14\ Raw materials such as shale, clay, and slate are
crushed and introduced at the upper end of the rotary kiln. In passing
through the kiln, the materials reach temperatures of 1,900-2,100 [deg]
F. Heat is provided by a burner at the lower end of the kiln where the
product is discharged. As the raw material is heated, it melts into a
semi-plastic state and begins to generate gases that serve as the
bloating or expanding agent. As temperatures reach their maximum, the
semi-plastic raw material becomes viscous and entraps the expanding
gases. This bloating action produces small, unconnected gas cells,
which remain in the material after it cools and solidifies. Lightweight
aggregate kilns are designed to expand the raw material by thermal
processing into a coarse aggregate used in the production of
lightweight concrete products such as concrete block, structural
concrete, and pavement.
---------------------------------------------------------------------------

\14\ Lightweight aggregate kilns that burn hazardous waste will
also remain subject to the RCRA Boilers and Industrial Furnace
emission limitations pursuant to Sec. 266 subpart H until they
demonstrate compliance with the interim MACT standards and remove
the emission limitations from their RCRA permit. See Sec. 270.42
appendix I, section a.8 and introductory paragraph to Sec. 270.66.
---------------------------------------------------------------------------

The lightweight aggregate kilns affected by this proposal burn
hazardous waste-derived fuels to replace some or all of normal fossil
fuels. Two of the facilities burn only liquid hazardous wastes, while
the third facility burns both liquid and solid wastes. The annual
hazardous waste fuel replacement rate is 100 percent.
In 2003, there were three lightweight aggregate kiln facilities in
two states operating a total of seven hazardous waste-fired kilns. All
lightweight aggregate kilns use baghouses to control particulate matter
and one facility also uses a venturi scrubber to control acid gas emissions.
4. Boilers That Burn Hazardous Waste
Boilers that burn hazardous waste are currently regulated under
RCRA at part 266, subpart H. We propose to use the RCRA definition of
boiler under 40 CFR 260.10 for purposes of today's rulemaking for
simplicity and continuity. This definition includes industrial,
commercial, and institutional boilers as well as thermal units known in
industry as process heaters. We propose to subcategorize boilers based
on the type of fuel that is burned, which would result in separate
emission standards for solid fuel-fired boilers and liquid fuel-fired
boilers. We discuss subcategorization options in more detail in Part
Two, Section II.
Boilers are typically described by either their design or type of
fuel burned. Hazardous waste burning boilers comprise two basic
different boiler designs--watertube and firetube. The choice of which
design to use depends on factors such as the desired steam quality,
thermal efficiency, size, economics, fuel type, and responsiveness.
Watertube boilers are those that flow the water through tubes running
the length of the boiler. The hot combustion gas surrounds these tubes,
causing the water inside to get hot. Most hazardous waste burning
boilers use this design. Watertube boilers can also burn a variety of
fuel types including coal, oil, gas, wood, and municipal or industrial
wastes. Firetube boilers are similar to watertube type, except the
placement of the water and combustion gas is reversed. Here the hot
combustion gas flows through the tubes, while the water surrounds the
tubes. This design does have some disadvantages, however, in that they
work well with only gas and liquid fuels.
Process heaters are similar to boilers (as conventionally defined),
except they heat a fluid other than water. This fluid is often an oil
or some other fluid with more suitable heating properties. Process
heaters are often used in circumstances where the amount of heat needed
is greater than what can be delivered by steam. For the purposes of
this rulemaking and consistent with current RCRA regulations, process
heaters would be classified as boilers.
Descriptions of liquid and solid fuel-fired boilers that burn
hazardous waste are provided below.
a. Liquid Fuel-Fired Boilers. A liquid fuel-fired boiler is a
device that meets the definition of a boiler under 40 CFR 260.10 and
that burns any combination of liquid and gas fuels, but no solids. See
proposed definition in Sec. 63.1201(a). A liquid fuel is defined as a
fuel that is pumpable (e.g., liquid wastes, sludges, or slurries). Most
liquid hazardous waste burning boilers co-fire natural gas, fuel oil,
or process gases to achieve the proper combustion temperatures and a
consistent steam supply.
There are approximately 104 liquid fuel-fired boilers that burn
hazardous waste, 85 of which have not installed back-end air pollution
control equipment. The rest of the liquid boilers use either a wet
scrubber, electrostatic precipitator, or fabric filter. These boilers
co-fire liquid hazardous waste with either natural gas or heating oil
at heat input rates of 10% to 100%.
b. Solid Fuel-Fired Boilers. A solid fuel-fired boiler is a device
that meets the definition of a boiler under 40 CFR 260.10 and that
burns solid fuels, including both pulverized and stoker coal.\15\ See
proposed definition in Sec. 63.1201(a). Boilers that co-fire solid
fuel with liquid or gaseous fuels are solid fuel-fired boilers.
---------------------------------------------------------------------------

\15\ Please note that the RCRA definition of boiler includes
devices defined under part 63 as boilers and process heaters.
---------------------------------------------------------------------------

There are 12 solid fuel-fired boilers that burn hazardous waste.
These boilers co-fire liquid hazardous waste with coal at heat input
rates of 6% to 33%. Nine of these boilers are stoker-fired, and three
burn pulverized coal. Two boilers are equipped with fabric filters to
control particulate matter and

[[Page 21209]]

metals, and 10 are equipped with electrostatic precipitators.
5. Hydrochloric Acid Production Furnaces That Process Hazardous Waste
Hydrochloric acid production furnaces that burn hazardous waste are
currently regulated under RCRA at part 266, subpart H. We propose to
use the RCRA definition of hydrochloric acid production furnace under
40 CFR 260.10 for purposes of today's rulemaking for simplicity and
continuity. See proposed definition in Sec. 63.1201(a).
Hydrochloric acid production furnaces burn chlorinated hazardous
wastes to make an aqueous hydrochloric acid for on-site use as an
ingredient in a manufacturing process. The hazardous waste feedstocks
have a chlorine content of over 20% by weight. The hydrochloric acid
produced by burning the chlorinated byproducts dissolves in the
scrubber water to produce an acid product containing hydrochloric acid
greater than 3% by weight. There are 17 hazardous waste burning
hydrochloric acid production furnaces currently in operation.
Chlorine-bearing feedstreams, wastes, and auxiliary fuels (usually
natural gas) are burned in these hydrochloric acid production furnaces
in a refractory lined chamber similar to a liquid waste incinerator
chamber. Combustion is maintained at a high temperature, with adequate
excess hydrogen to ensure the conversion of chlorine in the feedstreams
to hydrogen chloride in the combustion gases. Many furnaces also have
waste heat boilers, similar to those used by some incinerators, to
recover heat and return it to the production process. Others use a
water spray quench to cool the combustion gases.
The cooled combustion flue gas is routed to an acid recovery
system, consisting of multiple wet scrubbing absorption units. These
units are usually packed tower or film tray scrubbers which operate
with an acidic scrubbing solution. The scrubbing solution is recycled
to concentrate the acid until it reaches the desired concentration
level, at which point it is recovered for use as a valuable product. A
final polishing scrubber, operated with a caustic liquid solution, is
used to control emissions of hydrogen chloride and chlorine gas.

B. What HAP Are Emitted?

Incinerators, cement kilns, lightweight aggregate kilns, and
hydrochloric acid production furnaces that burn hazardous waste can
emit high levels of dioxin/furans depending on the design and operation
of the emission control equipment, and, for incinerators, whether a
waste heat recovery boiler is used. Our data base shows that boilers
that burn hazardous waste generally do not emit high levels of dioxin/
furans.
All hazardous waste combustors can emit high levels of other
organic HAP if they are not designed, operated, and maintained to
operate under good combustion conditions.
Hazardous waste combustors can also emit high levels of metal HAP,
depending on the level of metals in the waste feed and the design and
operation of air emissions control equipment. Hydrochloric acid
production furnaces, however, generally feed and emit low levels of
metal HAP.
Hazardous waste combustors can also emit high levels of particulate
matter, except that hydrochloric acid production furnaces generally
feed wastes with low ash content and emit low levels of particulate
matter.\16\ The majority of particulate matter emissions from hazardous
waste combustors is in the form of fine particulate (i.e., 50% or more
of the particulate matter emitted is 2.5 microns in diameter or
less).\17\ Particulate emissions from incinerators and liquid fuel-
fired boilers depend on the ash content of the waste feed and the
design and operation of air emission control equipment. Particulate
emissions from cement kilns and lightweight aggregate kilns are not
significantly affected by the ash content of the hazardous waste fuel
because uncontrolled particulate emissions are attributable primarily
to raw material entrained in the combustion gas. Thus, particulate
emissions from kilns depend on operating conditions that affect
entrainment of raw material, and the design and operation of the
emission control equipment.
---------------------------------------------------------------------------

\16\ Emissions of particulate matter are of interest because
metal HAP, except notably for mercury, are in the particulate form
in stack gas. Thus, controlling particulate matter controls metal HAP.
\17\ Particulate size distributions are somewhat dependent on
the type of combustor. See USEPA ``Draft Technical Support Document
for HWC MACT Replacement Standards, Volume V: Emission Estimates and
Engineering Costs,'' March 2004, Chapter 7 for more information.
---------------------------------------------------------------------------

C. Does Today's Proposed Rule Apply to My Source?

The following sources that burn hazardous waste are considered to
be affected sources subject to today's proposed rule: Incinerators,
cement kilns, lightweight aggregate kilns, boilers, and hydrochloric
acid production furnaces. Affected sources do not include: (1) Sources
exempt from regulation under 40 CFR part 266, subpart H, because the
only hazardous waste they burn is listed under 40 CFR 266.100(c); (2)
research, development, and demonstration sources exempt under Sec.
63.1200(b); and (3) boilers exempt from regulation under 40 CFR part
266, subpart H, because they meet the definition of small quantity
burner under 40 CFR 266.108. See Sec. 63.1200(b).
Affected sources also do not include emission points that are
unrelated to the combustion of hazardous waste (e.g., cement kiln
clinker cooler stack emissions, hydrochloric acid production facility
emissions originating from product or waste storage tanks and transfer
operations, etc.). This is because subpart EEE only controls HAP
emission points that are directly related to the combustion of
hazardous waste. Under separate rulemakings, the Agency has or will
establish MACT standards, where warranted, to control HAP emissions
from non-hazardous waste related emission points.
Hazardous waste combustors are affected sources irrespective of
whether they are major sources or area sources. As discussed in Part
Two, Section I.A, we are proposing to subject area sources of boilers
and hydrochloric acid production furnaces to the major source MACT
standards for mercury, dioxin/furans, carbon monoxide/hydrocarbons, and
destruction and removal efficiency pursuant to section 112(c)(6). As
promulgated in the 1999 rule, both area source and major source
incinerators, cement kilns, and lightweight aggregate kilns will
continue to be subject to the full suite of Subpart EEE emission standards.

D. What Emissions Limitations Must I Meet?

Under today's proposal, you would have to comply with the emission
limits in Tables 1 and 2. Note that these emission limitations are
discussed in greater detail for each source category (and subcategory)
in Part Two, Section VII thru XII. Note also that we are proposing
several alternative emission standards: (1) You may elect to comply
with an alternative to the particulate matter standard for incinerators
and liquid fuel-fired boilers that would limit emissions of total metal
HAP; and (2) you may elect to comply with an alternative to the total
chlorine standard applicable to all source categories, except
hydrochloric acid production furnaces, under which you may establish
site-specific, risk-based emission limits for hydrogen chloride and
chlorine gas based on national

[[Page 21210]]

exposure standards. These alternative standards are discussed in Part
Two, Section XVIII and Section XIII, respectively.

Table 1.--Proposed Standards for Existing Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hydrochloric acid
Incinerators Cement kilns Lightweight Solid fuel-fired Liquid fuel-fired production
aggregate kilns boilers \1\ boilers \1\ furnaces \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans ( ng TEQ/dscm).... 0.28 for dry APCD 0.20 or 0.40 + 0.40.............. CO or THC standard 0.40 for dry APCD 0.40
and WHB sources; 400[deg]F at APCD as a surrogate. sources; CO or HC
\6\ 0.40 for inlet. standard as
others. surrogate for
others.
Mercury......................... 130 ug/dscm....... 64 ug/dscm \2\.... 67 ug/dscm \2\.... 10 ug/dscm........ 3.7E-6 lb/MMBtu 2, Total chlorine
5. standard as
surrogate
Particulate Matter.............. 0.015 gr/dscf \8\. 0.028 gr/dscf..... 0.025 gr/dscf..... 0.030 gr/dscf \8\. 0.032 gr/dscf \8\. Total chlorine
standard as
surrogate
Semivolatile Metals (lead + 59 ug/dscm........ 4.0E-4 lbs/MMBtu 3.1E-4 lb/MMBtu 170 ug/dscm....... 1.1E-5 lb/MMBtu 2, Total chlorine
cadmium). \5\. \5\ and 250 ug/ 5. standard as
dscm \3\. surrogate
Low Volatile Metals (arsenic + 84 ug/dscm........ 1.4E-5 lbs/MMBtu 9.5E-5 lbs/MMBtu 210 ug/dscm....... 1.1E-4 lb/MMBtu 4, Total chlorine
beryllium + chromium). \5\. \5\ and 110 ug/ 5. standard as
dscm \3\. surrogate
Total Chlorine (hydrogen 1.5 ppmv \7\...... 110 ppmv \7\...... 600 ppmv \7\...... 440 ppmv \7\...... 2.5E-2 lb/MMBtu 14 ppmv or
chloride + chlorine gas). \5, 7\. 99.9927% system
removal
efficiency
Carbon Monoxide (CO) or 100 ppmv CO or 10 See Part Two, 100 ppmv CO or 20 (2) 100 ppmv CO or 10 ppmv HWC
Hydrocarbons HWC. ppmv HWC. Section VIII. ppmv HWC.
Destruction and Removal 99.99% for each principal organic hazardous pollutant. For sources burning hazardous wastes F020, F021, F022, F023,
Efficiency (DRE). F026, or F027, however, 99.9999% for each principal organic hazardous pollutant.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Particulate matter, semivolatile metal, low volatile, and total chlorine standards apply to major sources only for solid fuel-fired boilers, liquid
fuel-fired boilers, and hydrochloric acid production furnaces.
\2\ Standard is based on normal emissions data.
\3\ Sources must comply with both the thermal emissions and emission concentration standards.
\4\ Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal
total for liquid fuel-fired boilers.
\5\ Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.
\6\ APCD denotes ``air pollution control device'', WHB denotes ``waste heat boiler''.
\7\ Sources may elect to comply with site-specific, risk-based emission limits for hydrogen chloride and chlorine gas based on national exposure
standards. See Part Two, Section XIII.
\8\ Sources may elect to comply with an alternative to the particulate matter standard. See Part Two, Section XVIII.

Table 2.--Proposed Standards for New Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hydrochloric acid
Incinerators Cement kilns Lightweight Solid fuel boilers Liquid fuel production
aggregate kilns \1\ boilers \1\ furnaces \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans ( ng TEQ/dscm).... 0.11 for dry APCD 0.20 or 0.40 + 0.40.............. Carbon monoxide 0.015 or 400[deg]F 0.40
or WHBs \5\; 0.2 400[deg]F at (CO) or at the inlet to
for others. inlet to hydrocarbon (HC) particulate
particulate as a surrogate. matter control
matter control device for dry
device. APCD; CO or HC
standard as
surrogate for
others.
Mercury......................... 8 ug/dscm......... 35 ug/dscm \2\.... 67 ug/dscm \2\.... 10 ug/dscm........ 3.8E-7 lb/MMBtu 2, Tcl as surrogate
4.
Particulate matter.............. 0.00070 gr/dscf 0.0058 gr/dscf.... 0.0099 gr/dscf.... 0.015 gr/dscf \7\. 0.0076 gr/dscf \7\ TCL as surrogate
\7\.
Semivolatile Metals (lead + 6.5 ug/dscm....... 6.2E-5 lb/MMBtu 2.4E-5 lb/MMBtu 170 ug/dscm....... 4.3E-6 lb/MMBtu 2, TCL as surrogate
cadmium). \4\. \4\. 4.
Low Volatile Metals (arsenic + 8.9 ug/dscm....... 1.4E-5 lb/MMBtu 3.2E-5 lb/MMBtu 190 ug/dscm....... 3.6E-5 lb/MMBtu in TCL as surrogate
beryllium + chromium). \4\. \4\. HW 3, 4.
Total Chlorine (Hydrogen 0.18 ppmv \6\..... 78 ppmv \6\....... 600 ppmv \6\...... 73 ppmv \6\....... 7.2E-4 lb/MMBtu 4, 1.2 ppmv or
chloride + chlorine gas). 6. 99.99937% SRE

[[Page 21211]]

Carbon monoxide CO or 100 ppmv (CO) or See Part Two, 100 ppmv CO or 20 100 ppmv CO or 10 ppmv HWC
Hydrocarbons (HWC). 10 ppmv HWC. Section VIII. ppmv HWC.
Destruction and Removal 99.99% for each principal organic hazardous pollutant. For sources burning hazardous wastes F020, F021, F022, F023,
Efficiency. F026, or F027, however, 99.9999% for each principal organic hazardous pollutant.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards apply to major sources only for solid fuel-fired boilers,
liquid fuel-fired boilers, and hydrochloric acid production furnaces.
\2\ Standard is based on normal emissions data.
\3\ Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal
total for liquid fuel-fired boilers.
\4\ Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.
\5\ APCD denotes ``air pollution control device'', WHB denotes ``waste heat boiler''.
\6\ Sources may elect to comply with site-specific, risk-based emission limits for hydrogen chloride and chlorine gas based on national exposure
standards. See Part Two, Section XIII.
\7\ Sources may elect to comply with an alternative to the particulate matter standard. See Part Two, Section XVIII.

E. What Are the Testing and Initial Compliance Requirements?

We are proposing testing and initial compliance requirements for
solid fuel-fired boilers, liquid fuel-fired boilers and hydrochloric
acid production furnaces that are identical to those that are
applicable to incinerators, cement kilns, and lightweight aggregate
kilns already in place at Sec. Sec. 63.1206, 63.1207, and 63.1208.
Please note also that in Part Three of today's preamble we request
comment on, or propose revisions to, several testing and initial
compliance requirements. Any amendments to the testing and compliance
requirements that we promulgate as a result of those discussions would
be applicable to all hazardous waste combustors.
In addition, we are proposing to revise the existing initial
compliance requirements for incinerators, cement kilns, and lightweight
aggregate kilns. Under the proposed revision, owners and operators of
incinerators, cement kilns, and lightweight aggregate kilns would be
required to conduct the initial comprehensive performance test to
document compliance with the replacement standards proposed today
(Sec. Sec. 63.1219, 63.1220, and 63.1221) within 12 months of the
compliance date. Owners and operators of solid fuel-fired boilers,
liquid fuel-fired boilers and hydrochloric acid production furnaces
would be required to conduct an initial comprehensive performance test
within six months of the compliance date, and periodic comprehensive
performance tests every five years. The purpose of the comprehensive
performance test is to document compliance with the emission standards,
document that continuous monitoring systems meet performance
requirements, and establish limits on operating parameters that would
be monitored by continuous monitoring systems.
Owners and operators of liquid fuel-fired boilers equipped with a
dry air pollution control device and hydrochloric acid production
furnaces would be required to conduct a dioxin/furan confirmatory
performance test 2.5 years after each comprehensive performance test
(i.e., midway between comprehensive performance tests). The purpose of
the dioxin/furan confirmatory performance test is to document
compliance with the dioxin/furan standard when operating within the
range of normal operations. Owners and operators of solid fuel-fired
boilers, and liquid fuel-fired boilers that are not subject to a
numerical dioxin/furan emission standard (i.e., liquid fuel-fired
boilers other than those equipped with an electrostatic precipitator or
fabric filter), would be required to conduct a one-time dioxin/furan
test to enable the Agency to evaluate the effectiveness of the carbon
monoxide/hydrocarbon standard and destruction and removal efficiency
standard in controlling dioxin/furan emissions for those sources. The
Agency would use those emissions data when reevaluating the MACT
standards under section 112(d)(6) and when determining whether to
develop residual risk standards for these sources pursuant to CAA
section 112(f)(2).
Owners and operators of solid fuel-fired boilers, liquid fuel-fired
boilers and hydrochloric acid production furnaces would be required to
use the following stack test methods to document compliance: (1) Method
29 for mercury, semivolatile metals, and low volatile metals; and (2)
Method 26A for hydrogen chloride and chlorine gas; (3) either Method
0023A or Method 23 for dioxin/furans; and (4) either Method 5 or 5i for
particulate matter.
The following is a proposed time-line for testing and initial
compliance requirements for owners and operators of solid fuel-fired
boilers, liquid fuel-fired boilers and hydrochloric acid production
furnaces: (1) The compliance date is three years from publication of
the final rule; (2) you must place in the operating record a
Documentation of Compliance by the compliance date identifying that the
operating parameter limits you have determined using available
information will ensure compliance with the emission standards; (3) you
must commence the initial comprehensive performance test within six
months of the compliance date; (4) you must complete the initial
comprehensive performance test within 60 days of commencing the test;
and (5) you must submit a Notification of Compliance within 90 days of
completing the test documenting compliance with emission standards and
CMS requirements.

F. What Are the Continuous Compliance Requirements?

We are proposing continuous compliance requirements for solid fuel-
fired boilers, liquid fuel-fired boilers and hydrochloric acid
production furnaces that are identical to those already in place at
Sec. 63.1209 and applicable to incinerators, cement kilns, and
lightweight aggregate kilns. Please note, however, that in Part Three
of today's preamble we request comment on, or propose revisions to,
several continuous compliance requirements. Any amendments to the
continuous compliance requirements that we promulgate as a result of
those discussions would be applicable to all hazardous waste combustors.

[[Page 21212]]

Owners and operators of solid fuel-fired boilers, liquid fuel-fired
boilers and hydrochloric acid production furnaces would be required to
use carbon monoxide or hydrocarbon continuous emissions monitors (as
well as an oxygen continuous emissions monitor to correct the carbon
monoxide or hydrocarbon values to 7% oxygen) to ensure compliance with
the carbon monoxide or hydrocarbon emission limits.
Owners and operators of solid fuel-fired boilers, liquid fuel-fired
boilers and hydrochloric acid production furnaces would also be
required to establish limits on the feedrate of metals, chlorine, and
(for some source categories) ash, key combustor operating parameters,
and key operating parameters of the control device based on operations
during the comprehensive performance test. You must continuously
monitor these parameters with continuous monitoring systems. See Part
Two, Section XIV.C for a discussion of the specific parameters for
which you must establish limits.

G. What Are the Notification, Recordkeeping, and Reporting Requirements?

We are proposing notification, recordkeeping, and reporting
requirements for solid fuel-fired boilers, liquid fuel-fired boilers
and hydrochloric acid production furnaces that are identical to those
already in place at Sec. Sec. 63.1210 and 63.1211 and applicable to
incinerators, cement kilns, and lightweight aggregate kilns. Please
note, however, that we are proposing a new requirement applicable to
all hazardous waste combustors that would require you to submit a
Notification of Intent to Comply and a Compliance Progress Report. See
Part Two, Section XVI.B.
The proposed notification, recordkeeping, and reporting
requirements are summarized in Part Two, Section XVI.

Part Two: Rationale for the Proposed Rule

I. How Did EPA Determine Which Hazardous Waste Combustion Sources Would
Be Regulated

A. How Are Area Sources Regulated?

We are proposing to subject area source boilers and hydrochloric
acid production furnaces to the major source MACT standards for
mercury, dioxin/furan, carbon monoxide/hydrocarbons, and destruction
and removal efficiency pursuant to section 112(c)(6).\18\ Both area
source and major source incinerators, cement kilns, and lightweight
aggregate kilns will continue to be subject to the full suite of
Subpart EEE emission standards.\19\
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\18\ We are using carbon monoxide or hydrocarbons and
destruction and removal efficiency as surrogates for control of
polycyclic organic matter emissions.
\19\ In support of the 1999 Final Rule, EPA determined
incinerators, cement kilns, and lightweight aggregate kilns that are
area sources can emit HAP at levels that pose a hazard to human
health and the environment. Accordingly, EPA subjected area sources
within those source categories to the same emission standards that
apply to major sources. See 64 FR at 52837-38.
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Section 112(c)(6) of the CAA requires EPA to list and promulgate
section 112(d)(2) or (d)(4) standards (i.e., standards reflecting MACT)
for categories and subcategories of sources emitting seven specific
pollutants. Four of those listed pollutants are emitted by boilers and
hydrochloric acid production furnaces: mercury, 2,3,7,8-
tetrachlorodibenzofuran, 2,3,7,8-tetrachlorodibenzo-p-dioxin, and
polycyclic organic matter. EPA must assure that source categories
accounting for not less than 90 percent of the aggregated emissions of
each enumerated pollutant are subject to MACT standards. Congress
singled out the pollutants in section 112(c)(6) as being of ``specific
concern'' not just because of their toxicity but because of their
propensity to cause substantial harm to human health and the
environment via indirect exposure pathways (i.e., from the air through
other media, such as water, soil, food uptake, etc.). Furthermore,
these pollutants have exhibited special potential to bioaccumulate,
causing pervasive environmental harm in biota and, ultimately, human
health risks.
We estimate that approximately 1,800 pounds of mercury are emitted
annually in aggregate from hazardous waste burning boilers in the
United States.\20\ Also, we estimate that hazardous waste burning
boilers and hydrochloric acid production furnaces emit in aggregate
approximately 1.1 and 1.6 grams TEQ per year of dioxin/furan,
respectively. The Agency has already counted on the control of these
pollutants from area sources in the industrial/commercial/institutional
boiler source category when we accounted for at least 90 percent of the
emissions of these hazardous air pollutants as being subject to
standards under section 112(c)(6). See 63 FR 17838; April 10, 1998.
Therefore, we are proposing to subject boiler and hydrochloric acid
furnace area sources to the major source MACT standards for mercury,
dioxin/furan, carbon monoxide/hydrocarbons, and destruction and removal
efficiency pursuant to section 112(c)(6).
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\20\ See USEPA ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume V: Emission Estimates and Engineering
Costs,'' March, 2004, Chapter 3.
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We are proposing that only major source boilers and hydrochloric
acid furnaces would be subject to the full suite of subpart EEE
emission standards we propose today. Section 112(c)(3) of the CAA
requires us to subject area sources to the full suite of standards
applicable to major sources if we find ``a threat of adverse effects to
human health or the environment'' that warrants such action. We cannot
make this finding for area source boilers and halogen acid production
furnaces.\21\ Consequently, area sources in these categories would be
subject to the MACT standards for mercury, dioxin/furan, carbon
monoxide/hydrocarbons, and destruction and removal efficiency standards
only to control the HAP listed under section 112(c)(6). RCRA standards
under Part 266, Subpart H for particulate matter, metals other than
mercury, and hydrogen chloride and chlorine gas would continue to apply
to these area sources unless an area source elects to comply with the
major source standards in lieu of the RCRA standards. See proposed
Sec. 266.100(b)(3) and the proposed revisions to Sec. Sec. 270.22 and
270.66.
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\21\ We believe that two or fewer boilers are area sources. We
do not believe any hydrochloric acid production furnaces are area sources.
---------------------------------------------------------------------------

B. What Hazardous Waste Combustors Are Not Covered by This Proposal?

1. Small Quantity Burners
Boilers that are exempt from the RCRA hazardous waste-burning
boilers rule under 40 CFR 266.108 because they burn small quantities of
hazardous waste fuel would also be exempt from today's proposed rule.
Those boilers would be subject, however, to the MACT standards the
Agency has proposed for industrial/commercial/institutional boilers.
See 68 FR 1660, January 13, 2003.
The type and concentration of HAP emissions from boilers that co-
fire small quantities of hazardous waste fuel with other fuels under
Sec. 266.108 should be characterized more by the metals and chlorine
levels in the primary fuels and the effect of combustion conditions on
the primary fuels than by the composition and other characteristics of
the hazardous waste fuel. Under Sec. 266.108, boilers that burn small
quantities of hazardous waste fuel cannot fire hazardous waste at any
time at a rate greater than 1 percent of the

[[Page 21213]]

total fuel requirements for the boiler. In addition, a boiler with a
stack height of 20 meters or less cannot fire more than 84 gallons of
hazardous waste fuel a month, which would equate to an average firing
rate of 0.5 quarts per hour. Finally, the hazardous waste fuel must
have a heating value of 5,000 Btu/lb to ensure it is a bonafide fuel,
and cannot contain hazardous wastes that are listed because they
contain chlorinated dioxins/furans. Given these restrictions, we
believe that HAP emissions are not substantially related to the
hazardous waste fuels these boilers burn. Thus, these boilers are more
appropriately regulated under the MACT standards proposed at part 63,
subpart DDDDD, than the MACT standards proposed today for hazardous
waste combustors.
Boilers that burn small quantities of hazardous waste fuel under
Sec. 266.108 would become subject to part 63, subpart DDDDD, three
years after publication of the final rule for hazardous waste
combustors (i.e., the rules we are proposing today). Subpart DDDDD
exempts ``a boiler or process heater required to have a permit under
section 3005 of the Solid Waste Disposal Act [i.e., RCRA] or covered by
40 CFR part 63, subpart EEE (e.g., hazardous waste combustors).'' See
40 CFR 63.7491(d). Boilers that burn small quantities of hazardous
waste fuel under Sec. 266.108 are exempt from the substantive emission
standards of part 266, subpart H, and the permit requirements of 40 CFR
part 270 (establishing RCRA permit requirements). In addition, owners
and operators of such boilers would not know whether they are covered
by part 63, subpart EEE, until we promulgate the final rule for
hazardous waste combustors. Thus, it is appropriate to require that
these boilers begin complying with subpart DDDDD three years after we
publish the final rule for hazardous waste combustors.
2. Sources Exempt From RCRA Emission Regulation Under 40 CFR Part 266.100(c)
Consistent with the Phase I Hazardous Waste Combustor MACT rule
promulgated in 1999, we would not subject boilers and hydrochloric acid
production furnaces to today's proposed requirements if the only
hazardous waste combusted is exempt from regulation pursuant to Sec.
266.100(c), including certain types of used oil, landfill gas, and
otherwise exempt or excluded waste. This is appropriate because HAP
emissions from sources that qualify for this exemption would not be
significantly impacted by the combustion of hazardous waste. Thus,
emissions from these sources would be more appropriately regulated by
other promulgated MACT standards that specifically address emissions
from these sources.
3. Research, Development, and Demonstration Sources
Consistent with the Phase I Hazardous Waste Combustor MACT rule
promulgated in 1999, we would not subject boilers and hydrochloric acid
production furnaces that are research, development, and demonstration
sources to today's proposed requirements. We explained at promulgation
of the Phase I MACT standards that the hazardous waste combustor
emission standards may not be appropriate for research, development,
and demonstration sources because of their typically intermittent
operations and small size. See 64 FR at 52839. Given that emissions
from these sources are addressed under RCRA on case-by-case basis
pursuant to Sec. 270.65, we continue to believe this is appropriate,
and we are today proposing the same exemption for boilers and
hydrochloric acid production furnaces.

C. How Would Sulfuric Acid Regeneration Facilities Be Regulated?

Sulfuric acid regeneration facilities burn spent sulfuric acid and
sulfur-bearing hazardous wastes or hazardous waste fuel to produce
sulfuric acid and are subject to 40 CFR part 266, subpart H, (i.e., the
RCRA Boiler and Industrial Furnace Rule) as a listed industrial
furnace. We are not proposing MACT standards for these sources because
EPA did not list sulfuric acid regeneration facilities as a category of
major sources of HAP emissions. See 57 FR 31576 (July 16, 1992). We
obtained emissions and other data on these sources and confirmed that
they emit very low levels of HAP.\22\ Accordingly, these combustors
will remain subject to RCRA regulations under part 266, subpart H.
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\22\ See U.S. EPA, ``Draft Technical Support Document for HWC
MACT Replacement Standards, Volume II: HWC Emissions Data Base,'' March 2004.
---------------------------------------------------------------------------

II. What Subcategorization Considerations Did EPA Evaluate?

CAA section 112(d)(1) allows us to distinguish amongst classes,
types, and sizes of sources within a category when establishing floor
levels. Subcategorization typically reflects ``differences in
manufacturing process, emission characteristics, or technical
feasibility.'' See 67 FR 78058. A classic example, provided in the
legislative history to CAA 112(d), is of a different process leading to
different emissions and different types of control strategies--the
specific example being Soderberg and prebaked anode primary aluminum
processes. See ``A Legislative History of the Clean Air Act Amendments
of 1990,'' vol. 1 at 1138-39 (floor debates on Conference Report). If
we determine, for instance, that a given source category includes
sources that are designed differently such that the type or
concentration of HAP emissions are different we may subcategorize these
sources and issue separate standards.
We have determined that it is appropriate to subcategorize sources
that combust hazardous waste from those sources that do not. EPA
published an initial list of categories of major and area sources of
HAP selected for regulation in accordance with section 112(c) of the
Act on July 16, 1992 (57 FR 31576). Hazardous waste incineration,
Portland cement manufacturing, clay products manufacturing (including
lightweight aggregate manufacturing), industrial/commercial/
institutional boilers and process heaters, and hydrochloric acid
production are among the listed 174 categories of sources. Although
some cement kilns, lightweight aggregate kilns, boilers and process
heaters, and hydrochloric acid production furnaces burn hazardous
waste, EPA did not list hazardous waste burning sources as separate
source categories. Nonetheless, we generally believe that hazardous
waste combustion sources can emit different types or concentrations of
HAP emissions because hazardous waste combustors: (1) Have different
fuel HAP concentrations; (2) use different control techniques (e.g.,
feed control); and (3) have a different regulatory history given that
their toxic emissions were regulated pursuant to RCRA standards. As a
result, we believe it is appropriate to subcategorize each source
category listed above to define sources that burn hazardous waste as a
separate classes of combustors. We also assessed if further subdividing
each class of hazardous waste burning combustors is warranted using
both engineering judgement and statistical analysis. In our proposed
approach, we first use engineering information and principles to
identify potential subcategorization options. We then determine if
there is a statistical difference in the emission characteristics
between these options. See Part Two, Section VI.C for a discussion of
this statistical analysis. Finally, we review the results of the
statistical analysis to determine whether they are an appropriate basis for

[[Page 21214]]

subcategorization.\23\ We describe below the subcategorization options
we considered for each source category.
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\23\ For example, although the statistical analysis may find a
significant difference in emission levels between potential
subcategories, the emission levels may be more a function of the
emission control equipment rather than a function of the design and
operation of the combustors within the subcategories. If differences
in emission levels are attributable to use of different emission
control devices, and if there is nothing inherent in the design or
operation of sources in both subcategories that would preclude
applicability of those control devices, subcategorization would not
be warranted.
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A. What Subcategorization Options Did We Consider for Incinerators?

We considered whether to propose separate standards for three
hazardous waste incinerator subcategory options. First, we assessed
whether government-owned incinerator facilities had different emission
characteristics when compared to non-government facilities for the
mercury, semivolatile metal, low volatile metal, particulate matter,
and total chlorine floors. After evaluating the data, we determined
that emission characteristics from these two subcategories are not
statistically different, and, therefore are not proposing separate
emission standards.
Second, we assessed whether liquid injection incinerators emitted
significantly different levels of metals and particulate matter
compared to incinerators that feed solid wastes (e.g., rotary kilns,
fluid bed units, and hearth fired units). We define liquid injection
units as those incinerators that exclusively feed pumpable waste
streams and solid feed units as those that feed a combination of liquid
and solid wastes. We determined that emissions of metal HAP from these
potential subcategories are not statistically different.\24\ We,
therefore, are not proposing separate emission standards for metal HAP.
The statistical analysis for particulate matter shows that emissions
from liquid feed injection incinerators are higher than emissions from
solid feed injection units. However, we believe that separate standards
for particulate matter are not warranted because the difference in
emissions was more a factor of the types of back-end air pollution
devices used by the sources rather than incinerator design. We would
expect particulate emissions to be potentially higher for solid feed
units, not lower, because solid feed units have higher ash feedrates
and air pollution control device inlet particulate matter loadings.
Therefore, we must conclude that the difference is the product of less
effective back-end air pollution control.
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\24\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 4.
---------------------------------------------------------------------------

Third, we assessed whether incinerators equipped with dry air
pollution control devices and/or waste heat boilers have different
dioxin/furan emission characteristics when compared to other sources,
i.e., sources with either wet air pollution control or no air pollution
control devices. Our statistical analysis determined that dioxin/furan
emissions from sources equipped with waste heat boilers and/or dry air
pollution control devices are higher.\25\ We believe use of wet air
pollution control systems (and use of no air pollution control system)
can result in different dioxin/furan emission characteristics because
they have different post-combustion particle residence times and
temperature profiles, which can affect dioxin/furan surface catalyzed
formation reaction rates. As a result, we believe that it is
appropriate to subcategorize these different types of combustors.
---------------------------------------------------------------------------

\25\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 4.
---------------------------------------------------------------------------

Note that we do not subcategorize based on the type of air
pollution control device used. See 69 FR 394 (January 5, 2004). Dioxin/
furan emission characteristics are unique in that they are not
typically fed into the combustion device, but rather are formed in the
combustor or post combustion within ductwork, a heat recovery boiler,
or the air pollution control system. Wet and dry air pollution control
systems are generally not considered to be dioxin/furan control systems
because their primary function is to remove metals and/or total
chlorine from the combustion gas. They generally do not remove dioxin/
furans from the incinerator flue gas unless they are used in tandem
with carbon injection systems or carbon beds. (In contrast, carbon
injection systems and carbon beds are considered to be dioxin/furan air
pollution control systems). Thus, the differences in dioxin formation
here reflect something more akin to a process difference resulting in
different emission characteristics, rather than a difference in
pollution-capture efficiencies among pollution control devices. We thus
are not proposing to subcategorize based on whether a source is
equipped with a dioxin/furan control system.
We also considered whether to further subcategorize based on the
presence of a waste heat boiler or dry air pollution control device.
Our analysis determined that dioxin/furan emissions from incinerators
with waste heat boilers are not statistically different from those
equipped with dry air pollution control devices.\26\ We conclude that
further subcategorization is not necessary. See Part Two, Section VII.A
for more discussion on the proposed dioxin/furan standards for incinerators.
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\26\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 4.
---------------------------------------------------------------------------

B. What Subcategorization Options Did We Consider for Cement Kilns?

We considered subdividing hazardous waste burning cement kilns by
the clinker manufacturing process: wet process kilns without in-line
raw mills versus preheater/precalciner kilns with in-line raw mills.
All cement kilns that burn hazardous waste use one of these clinker
manufacturing processes. Based on available emissions data, we
evaluated design and operating features of each process to determine if
the features could have a significant impact on emissions. For the
reasons discussed below, we believe that subcategorization is not warranted.
In the wet process, raw materials are ground, wetted, and fed into
the kiln as a slurry. Twenty-two of the 25 cement kilns that burn
hazardous waste use the wet process to manufacture clinker. In the
preheater/precalciner kilns, raw materials are ground dry in a raw mill
and fed into the kiln dry. The remaining three of the 25 cement kilns
burning hazardous waste use preheater/precalciner kilns with in-line
raw mills.
Combustion gases and raw materials move in a counterflow direction
inside a cement kiln for both processes. The kiln is inclined, and raw
materials are fed into the upper end while fuels are typically fired
into the lower end. Combustion gases move up the kiln counter to the
flow of raw materials. The raw materials get progressively hotter as
they travel down the length of the kiln. The raw materials begin to
soften and fuse at temperatures between 2,250 and 2,700 [deg]F to form
the clinker product.
Wet process kilns are longer than the preheater/precalciner kilns
in order to facilitate evaporation of the water from the slurried raw
material. The preheater/precalciner kilns begin the calcining process--
heating of the limestone to drive off carbon dioxide to obtain lime
(calcium oxide)--before the raw materials are fed into the kiln. This
is accomplished by routing the flue gases from the kiln up through the
preheater tower while the raw materials are passing down the preheater tower.

[[Page 21215]]

The heat of the flue gas is transferred to the raw material as they
interact in the preheater tower. The precalciner is a secondary firing
system--typically fired with coal--located at the base of the preheater tower.
Though not necessary in a wet process kiln, a preheater/precalciner
kiln uses an alkali bypass designed to divert a portion of the flue gas
to remove problematic volatile constituents such as alkalies (potassium
and sodium oxides), chlorides, and sulfur that, if not removed, can
lead to operating problems. In addition, removal of the alkalies is
necessary so that their concentrations are below maximum acceptable
levels in the clinker. An alkali bypass diverts between 10-30% of the
kiln off-gas before it reaches the lower cyclone stages of the
preheater tower. Without use of a bypass, the high concentration of
volatile constituents at the lower cyclone stage of the preheater tower
would create operational problems. Bypass gases are quenched and sent
to a dedicated particulate matter control device to capture and remove
the volatile constituents.
All preheater/precalciner kilns that burn hazardous waste use the
hot flue gases to dry the raw materials as they are being ground in the
in-line raw mill. Typically, the raw mill is operating or ``on''
approximately 85% of the time. The kilns with in-line raw mills must
operate both in the ``on'' mode--gases are routed through the raw mill
supporting raw material drying and preparation--and in the ``off''
mode--necessary down time for raw mill maintenance. Given that there
are few preheater/precalciner cement kilns that burn hazardous waste,
we had limited emissions data to evaluate to see if there was a
significant difference in emissions. Moreover, we do not have any data
from a preheater/precalciner kiln operating under similar operating
conditions (e.g., metals and chlorine feed concentrations) both for the
``on'' mode and ``off'' mode.
We evaluated whether there was a significant difference in HAP
emissions between wet process kilns without in-line raw mills versus
preheater/precalciner kilns with in-line raw mills. We found a
statistically significant difference in mercury emissions between wet
process kilns and preheater/precalciner kilns in the ``off'' mode.\27\
But, we conclude that there is no significant difference in emissions
of dioxin/furans, particulate matter, semivolatile metals, low volatile
metals, and total chlorine between these types of kiln systems.\28\
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\27\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 4.
\28\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume V: Emission Estimates and Engineering
Costs'', March 2004, Chapter 4.
---------------------------------------------------------------------------

For wet process cement kilns without in-line raw mills, mercury
remains in the vapor phase at the typical operating temperatures in the
kiln and particulate matter control equipment, and exits the kiln as
volatile stack emissions with only a small fraction partitioning to the
clinker or cement kiln dust. In the preheater/precalciner kilns with
in-line raw mill, we believe that a significant portion of the
volatilized mercury condenses on to the surfaces of the cooler raw
material in the operating raw mill. The raw material with adsorbed
mercury ends up in the raw material storage bin which will eventually
be fed to the kiln and re-volatilized. During the periods that the in-
line raw mill is ``on'', mercury is effectively captured in the raw
mill essentially establishing an internal recycle loop of mercury that
builds-up within the system. Eventually, when the in-line raw mill
switches to the ``off'' mode, the re-volatilized mercury exits the kiln
as volatile stack emissions. Notwithstanding the apparent removal of
mercury during periods that the in-line raw mill is ``on'' in a
preheater/precalciner kiln, over time the mercury is emitted eventually
as volatile stack emissions because system removal efficiencies for
mercury are essentially zero. Thus, over a longer period of time (e.g.,
one month), the mass of mercury emitted by a wet process kiln without
an in-line raw mill and a preheater/precalciner kiln with an in-line
raw mill (assuming identical mercury-containing feedstreams) would be
the same. However, at any given point in time, the stack gas
concentration of mercury of the two types of kilns could be
significantly different.
As noted above, our data base shows a significant difference in
mercury emissions between preheater/precalciner kilns when operating in
the ``off'' mode and emissions both from wet process kilns and
preheater/precalciner kilns in the ``on'' mode. In spite of this
difference, we don't believe it is technically justified to
subcategorize cement kilns for mercury.\29\
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\29\ We note that in the September 1999 final rule we
established a provision that allows cement kilns operating in-line
raw mills to average their emissions based on a time-weighted
average concentration that considers the length of time the in-line
raw mill is on-line and off-line. See Sec. 63.1204(d).
---------------------------------------------------------------------------

In conclusion, we propose not to subcategorize the hazardous waste
burning class of cement kilns by wet process kilns and preheater/
precalciner kilns with in-line raw mills.

C. What Subcategorization Options Did We Consider for Lightweight
Aggregate Kilns?

Following promulgation of the September 1999 Final Rule, Solite
Corporation filed a Petition for Review challenging the total chlorine
standard for new kilns. For new sources, the Clean Air Act states that
the MACT floor cannot be ``less stringent than the emission control
that is achieved by the best controlled similar source.'' Solite
Corporation challenged the standard on the ground that Norlite
Corporation, another hazardous waste-burning lightweight aggregate kiln
source, should not be the best controlled similar source because they
are designed to burn for purposes of treatment hazardous wastes
containing high levels of chlorine and high mercury. Solite states that
Norlite's superior emission control equipment is designed to control
the chlorine and mercury in these wastes that are burned for treatment,
rather than primarily as fuel for lightweight aggregate production.
Thus, Solite states that Norlite's sources should be considered a
separate class of lightweight aggregate kilns.
Though we believe that subcategorizing by the concentrations of HAP
in the hazardous waste is not appropriate, we considered subdividing
hazardous waste burning lightweight aggregate kilns by the types of
hazardous waste they combust: low Btu wastes with higher concentrations
of chlorine and mercury and high Btu wastes with lower concentrations
of chlorine and mercury. We believe, however, that separate emission
standards for lightweight aggregate kilns based on the types of
hazardous waste they burn are unnecessary because the floor levels
would not differ significantly under either approach.
Analysis of available total chlorine emissions from compliance
testing indicates that the emissions are significantly different for
sources burning hazardous waste with high levels of chlorine compared
to sources burning wastes with much lower levels of chlorine. Total
chorine emissions range from 14 to 116 ppmv for sources feeding higher
concentrations of chlorine but using a venturi scrubber to control
emissions and range from 500 to 2,400 ppmv for sources feeding waste
with lower levels of chlorine and not using a wet scrubber. However,
when we identify floor levels for these potential subcategories (both
for existing and new sources), the calculated floor

[[Page 21216]]

level would be less stringent than the interim emission standard
sources are currently achieving. Because all sources are achieving the
more stringent interim standard, the interim standard becomes the
default floor level. Therefore, subdividing would not affect the
proposed floor level.
We have compliance test mercury emissions data representing maximum
emissions for only one source, and we have snap-shot mercury emissions
data within the range of normal emissions for all sources. Snap-shot
mercury emissions range from: (1) 11 to 20 ug/dscm for sources with the
potential to feed higher concentrations of mercury because they use a
venturi scrubber to control emissions; and (2) 1 to 47 ug/dscm for
sources that typically feed lower mercury containing wastes and do not
use a wet scrubber to control mercury. We performed a statistical test
and confirmed that there is no statistically significant difference in
the snap-shot mercury emissions between sources that have the potential
to feed higher levels of mercury because they are equipped with a wet
scrubber and with other sources. Therefore, it appears that
subcategorization for mercury is not warranted.\30\
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\30\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standard, Volume III: Selection of MACT Standards'',
March 2004, Chapter 4.
---------------------------------------------------------------------------

D. What Subcategorization Options Did We Consider for Boilers?

We discuss below the rationale for proposing to subcategorize
boilers by the physical form of the fuels they burn--solid fuel-fired
boilers and liquid fuel-fired boilers. We also discuss further
subcategorization options we considered for each of those subcategories
and explain why we believe that further subcategorization is not warranted.
1. Subcategorization by Physical Form of Fuels Burned
There are substantial design differences and emission
characteristics among boilers that cofire hazardous waste primarily
with coal versus oil or gas. Because of these differences, it is
appropriate to subcategorize boilers by the physical form of the fuel
burned. We note that the Agency has already proposed that industrial/
commercial/institutional boilers and process heaters that do not burn
hazardous waste should be subcategorized by the physical form of fuels
fired.\31\
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\31\ See 68 FR at 1670 (January 13, 2003).
---------------------------------------------------------------------------

Twelve boilers cofire hazardous waste with coal. These boilers are
designed to handle high ash content solid fuels, including the
relatively large quantities of boiler bottom ash and particulate matter
that are entrained in the combustion gas. The coal also contributes to
emissions of metal HAP. Approximately 104 boilers co-fire hazardous
waste with natural gas or fuel oil. These units are not designed to
handle the high ash loadings that are associated with coal-fired units,
and the primary fuels for these boilers contribute little to HAP
emissions. See ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume I: Description of Source Categories''
(Chapter 2.4) and ``Volume III: Selection of MACT Standards'' (Chapter
4) for a discussion of the design differences between liquid and coal
fuel-fired boilers.
Because the type of primary fuel burned dictates the design of the
boiler and emissions control systems, and can affect the concentration
of HAP, it is appropriate to subcategorize boilers by the physical form
of the fuel.
2. Subcategorization Considerations Among Solid Fuel Boilers
We considered whether to subcategorize solid fuel-fired boilers to
establish separate particulate matter standards. All 12 of the solid
fuel-fired boilers co-fire hazardous waste with coal. Three of the 12
boilers burn pulverized coal while the remaining nine are stoker-fired
boilers. Pulverized coal-fired boilers have higher uncontrolled
emissions than stoker-fired boilers because the coal is pulverized to a
talcum powder consistency and burned in suspension. Stoker-fired
boilers burn lump coal partially or totally on a grate. Thus, much more
of the coal ash is entrained in the combustion gas for pulverized coal-
fired boilers than for stoker-fired boilers.
Although the pulverized coal-fired boilers have higher uncontrolled
particulate matter emissions (i.e., at the inlet to the emission
control device), controlled emissions from the pulverized coal-fired
boilers are not statistically different than emissions from the stoker-
fired boilers, primarily because all solid fuel-fired boilers are
equipped with either a baghouse or electrostatic precipitator.\32\
Accordingly, we conclude that it is not appropriate to establish
separate particulate matter standards for pulverized coal-fired boilers
versus stoker-fired boilers. This is consistent with the proposal for
industrial/institutional/commercial boilers and process heaters that do
not burn hazardous waste.
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\32\ See USEPA ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 4.
---------------------------------------------------------------------------

3. Subcategorization Considerations for Liquid Fuel Boilers
We believe it is appropriate to combine liquid and gas fuel boilers
into one subcategory because emissions from gas fuel boilers are within
the range of emissions one finds from liquid fuel boilers. Also, most
of the hazardous waste burning liquid fuel boilers, in fact, burn gas
fossil fuels to supplement the liquid hazardous waste fuel. Even though
there are no hazardous waste gas burning boilers currently in
operation, today we propose to subject hazardous waste gas burning
boilers that may begin operating in the future to the standards for
liquid fuel-fired boilers. See proposed definition of liquid boiler in
Sec. 63.2101(a).
We also assessed whether liquid fuel-fired boilers equipped with
dry air pollution control devices had different dioxin/furan emission
characteristics when compared to other sources, i.e., sources with
either wet air pollution control devices or no air pollution control
device. Our statistical analysis indicated that dioxin/furan emissions
from sources equipped with dry air pollution control devices are
higher.\33\ We believe use of wet air pollution control systems (and
use of no air pollution control system) can result in different dioxin/
furan emission characteristics because they have different post-
combustion particle residence times and temperature profiles, which can
affect dioxin/furan surface catalyzed formation reaction rates. As a
result, we believe that it is appropriate to have different
subcategories for these different types of combustors. As discussed
previously for incinerators in Part Two, Section II.A, the differences
in dioxin formation here reflect something more akin to a process
difference resulting in different emission characteristics, rather than
a difference in pollution-capture efficiencies among pollution control
devices. We thus are not subcategorizing based on whether a source is
equipped with a dioxin/furan control system.
---------------------------------------------------------------------------

\33\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 4.
---------------------------------------------------------------------------

E. What Subcategorization Options Did We Consider for Hydrochloric Acid
Production Furnaces?

Consistent with our incinerator subcategorization analysis (see
Section A of this Part), we also considered whether to establish
separate floor emission standards for dioxin/furans for

[[Page 21217]]

hydrochloric acid production furnaces equipped with waste heat recovery
boilers versus those without boilers. As discussed below, we conclude
that there is no significant statistical difference in dioxin/furan
emissions between furnaces equipped with boilers and those without
them. As a result we do not propose to have different subcategories for
these sources.
Ten of the 16 hydrochloric acid production furnaces are equipped
with waste heat recovery boilers, and all hydrochloric acid production
furnaces are equipped with wet scrubbers that quench the combustion gas
immediately after it exits the furnace or boiler. We have dioxin/furan
emissions data for eight of the ten furnaces with boilers. Two furnaces
have low dioxin/furan emissions--approximately 0.1 ng TEQ/dscm, while
the other six furnaces have emissions ranging from 0.5 to 6.8 ng TEQ/
dscm. We have dioxin/furan emissions data for five of the six furnaces
without boilers. Dioxin/furan emissions for four furnaces are below
0.15 ng TEQ/dscm. But, one furnace has dioxin/furan emissions of 1.7 ng
TEQ/dscm.
It appears that dioxin/furan emissions from hydrochloric acid
production furnaces may not be governed by whether the furnace is
equipped with a waste heat recovery boiler. We performed a statistical
test and confirmed that there is no statistically significant
difference in dioxin/furan emissions between furnaces equipped with
boilers and those without boilers.\34\ Thus, we conclude that it is not
appropriate to establish separate dioxin/furan emission standards for
furnaces with boilers and those without boilers.
---------------------------------------------------------------------------

\34\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 4.
---------------------------------------------------------------------------

III. What Data and Information Did EPA Consider To Establish the
Proposed Standards?

The proposed standards are based on our hazardous waste combustor
data base. The data base contains general facility information, stack
gas emissions data, combustor design information, composition and feed
concentration data for the hazardous waste, fossil fuel, and raw
materials, combustion unit operating conditions, and air pollution
control device operating information. We gathered the emissions data
and information from test reports submitted by hazardous waste
combustor facilities to EPA Regional Offices or State agencies. Many of
the test reports were prepared as part of the compliance demonstration
process for the current RCRA standards, and may include results from
trial burns, certification of compliance demonstrations, annual
performance tests, mini-burns, and risk burns.

A. Data Base for Phase I Sources

The current data base for Phase I sources contain test results for
over 100 incinerators, 26 cement kilns, and 9 lightweight aggregate
kilns. In many cases, especially for cement and lightweight aggregate
kilns, the data base contain test reports from multiple testing
campaigns. For example, our data base includes results for a cement
kiln that conducted emissions testing for the years 1992, 1995, and 2000.
We first compiled a data base for hazardous waste burning
incinerators, cement kilns, and lightweight aggregate kilns to support
the proposed MACT standards in 1996 (61 FR 17358, April 19, 1996).
Based on public comments, a revised Phase I data base was published for
public comment (62 FR 960, January 7, 1997). The data base was again
revised based on public comments, and we used this data base to develop
the Phase I MACT standards promulgated in 1999 (64 FR 52828, September
30, 1999).
Following promulgation of the interim standards, we initiated a
data collection effort in early 2002 to obtain additional test reports.
The effort focused on obtaining test reports from sources for which we
had no information, obtaining data from more recent testing, and
updating the list of operating Phase I sources. Sources once identified
as hazardous waste combustors, but that have since ceased operations as
a hazardous waste combustor, were removed from the data base. This
revised data base was noticed for public comment in July 2002 (67 FR
44452, July 2, 2002) and updated based on public comments. See USEPA
``Draft Technical Support Document for HWC MACT Replacement Standards,
Volume II: HWC Emissions Data Base,'' March 2004, Appendix A for
comments and responses.
In comments on the data base notice, industry stakeholders question
whether emissions data obtained for some sources are appropriate to use
to identify MACT floor for today's proposed replacement standards.
Stakeholders suggest that it is inappropriate to use emissions data
from sources that tested after retrofitting their emission control
systems to meet the emission standards promulgated in September 1999
(and since vacated and replaced by the February 2002 Interim
Standards). Stakeholders refer to this as MACT-on-MACT: establishing
MACT floor based on sources that already upgraded to meet the 1999
standards. Stakeholders identified emissions data from only
approximately three of the Phase I sources (all incinerators) as being
obtained after the source upgraded to meet the 1999 standards. None of
these incinerator sources are consistently identified as a best
performer when establishing the proposed MACT standards.
Notwithstanding stakeholder concerns, we believe it is appropriate
to consider all of the data collected in the 2002 effort.\35\ First,
section 112(d)(3) states that floor standards for existing sources are
to reflect the average emission achieved by the designated per cent of
best performing sources ``for which the Administrator has emissions
information'' (emphasis added). Second, the motivation for a source's
performance is legally irrelevant in developing MACT floor levels.
National Lime Ass'n v. EPA, 233 F. 3d at 640. In any case, it would be
problematic to identify sources that upgraded their facilities (and
reduced their emissions) for purposes of complying with the 1999
standards versus for other purposes (e.g., normal replacement
schedule). Moreover, the MACT-on-MACT formulation is not correct.
Although the Interim Standards did result in reduction of emissions
from many sources, those standards are not MACT standards, and do not
purport to be. See February 13, 2002, Interim Standards Rulemaking, 67
FR at 7693. Finally, we note that, although we were prepared to use the
same data base for today's proposed rules as we used for the September
1999 rule to save the time and resources required to collect new data,
industry stakeholders wanted to submit new emissions data for us to
consider in developing the replacement standards. Rather than allowing
industry stakeholders to submit potentially selected emissions data,
however, we agreed to undertake a substantial data collection effort in
2002. It is unfortunate that industry stakeholders now suggest that
some portion of the new data is not appropriate for establishing MACT.
---------------------------------------------------------------------------

\35\ However, we did not consider emissions data from Ash Grove
Cement Company (Chanute, Kansas), an owner and operator of a new
preheater/precalciner kiln, because the test report is a MACT
comprehensive performance test demonstrating compliance with the new
source standards of the September 1999 final rule. We judged these
data are inappropriate for consideration for the floor analyses for
existing sources.
---------------------------------------------------------------------------

Notwithstanding our view that all of the 2002 data base should be
considered in establishing MACT standards, we

[[Page 21218]]

specifically request comment on: (1) Whether emissions data should be
deleted from the data base that were obtained from sources that owners
and operators assert were upgraded to meet the 1999 rule; and (2)
whether, because it may be problematic to identify such data, we should
identify MACT using the original 1999 data base.
Stakeholders have also raised concerns that the Agency may be
considering inappropriately emissions data in its MACT analyses based
on the language of section 112(d)(3)(A) of the Clean Air Act. Section
112(d)(3)(A) says emissions standards for existing sources shall not be
less stringent, and may be more stringent than--

the average emission limitation achieved by the best performing 12
percent of the existing sources (for which the Administrator has
emissions information), excluding those sources that have, within 18
months before the emission standard is proposed or within 30 months
before such standard is promulgated, whichever is later, first
achieved a level of emission rate or emission reduction which
complies, or would comply if the source is not subject to such
standard, with the lowest achievable emission rate (as defined by
section 171) applicable to the source category and prevailing at the
time, in the category or subcategory for categories and
subcategories with 30 or more sources,

Section 171 pertains to nonattainment areas for a particular
pollutant. The lowest achievable emission rate (LAER) for a pollutant
in a nonattainment area is the most stringent emission limitation which
is contained in the implementation plan of any State, or the most
stringent emission limitation which is achieved in practice. Given that
stakeholders neither identified any lowest achievable emission rates
for any pollutants applicable to nonattainment areas nor identified any
sources that are subject to such lowest achievable emission rates, we
conclude that there are no sources to exclude.

B. Data Base for Phase II Sources

Phase II sources are comprised of boilers and hydrochloric acid
production furnaces that burn hazardous waste. The data base for Phase
II sources was initially compiled by EPA in 1999. In developing this
data base, we collected the most recent test report available for each
source that included test results under compliance test operating
conditions. The most recent test report, however, may have also
included data used for other purposes (e.g., risk burn to obtain data
for a site-specific risk assessment), which are also included in the
data base. In nearly all instances, the dates of the test reports
collected were either 1998 or 1999.
After the initial compilation, we published the Phase II data base
for public comment in June 2000 (65 FR 39581, June 27, 2000). Since the
June 2000 notice, we have not collected additional emissions data for
Phase II sources; however, we revised the data base to address public
comments received in response to the June 2000 notice. We noticed the
Phase II data base (together with the one for Phase I sources) for
public comment in July 2002 (67 FR 44452, July 2, 2003) and revised the
data base based on comments received. The current data base for Phase
II sources contains test reports for over 115 boilers and 17
hydrochloric acid production furnaces. See USEPA ``Draft Technical
Support Document for HWC MACT Replacement Standards, Volume II: HWC
Emissions Data Base,'' March 2004.

C. Classification of the Emission Data

The hazardous waste combustor data base \36\ comprises emissions
data from tests conducted for various purposes, including compliance
testing, risk burns, annual performance testing, and research testing.
Therefore, some emissions data represent the highest emissions the
source has emitted in each of its compliance demonstrations, some data
represent normal or typical operating conditions and emissions, and
some data represent operating conditions and emissions during
compliance testing in a test campaign where there are other compliance
tests with higher emissions.
---------------------------------------------------------------------------

\36\ Though the Phase I and II data bases were developed and
titled separately, for purposes of today's proposal we are combining
both into one data base termed the ``hazardous waste combustor data base.''
---------------------------------------------------------------------------

Hazardous waste combustors generally emit their highest emissions
during RCRA compliance testing while demonstrating compliance with
emission standards. For real-time compliance assurance, sources are
required to establish limits on particular operating parameters that
are representative of operating levels achieved during compliance
testing. Thus, the emission levels achieved during these compliance
tests are typically the highest emission levels a source emits under
reasonably anticipable circumstances. To ensure that these operating
limits do not impede normal day-to-day operations, sources generally
take measures to operate during compliance testing under conditions
that are at the extreme high end of the range of normal operations. For
example, sources often feed ash, metals, and chlorine during compliance
testing at substantially higher than normal levels (e.g., by spiking
the waste feed) to maximize the feed concentration, and they often
detune the air pollution control equipment to establish operating
limits on the control equipment that provide operating flexibility. By
designing the compliance test to generate emissions at the extreme high
end of the normal range of emissions, sources can establish operating
limits that account for variability in operations (e.g., composition
and feedrate of feedstreams, as well as variability of pollution
control equipment efficiency) and that do not impede normal operations.
The data base also includes normal emissions data that are within
the range of typical operations. Sources will sometimes measure
emissions of a pollutant during a compliance test even though the test
is not designed to establish operating limits for that pollutant (i.e.,
it is not a compliance test for the pollutant). An example is a trial
burn where a lightweight aggregate kiln measures emissions of all RCRA
metals, but uses the Tier I metals feedrate limit to comply with the
mercury emission standard.\37\ Other examples of emissions data that
are within the range of normal emissions are annual performance tests
that some sources are required to conduct under State regulations, or
RCRA risk burns. Both of these types of tests are generally performed
under normal operating conditions, and would not necessarily reflect
day-to-day emission variability. However, such data may be appropriate
to use to evaluate long-term average performance.
---------------------------------------------------------------------------

\37\ A Tier 1 feedrate limit is a conservative compliance option
offered pursuant to RCRA requirements which assumes all of the
metal/chlorine that is fed to the combustion unit is emitted
(uncontrolled). Sources electing to comply with Tier 1 limits are
not required to conduct emissions testing and are not required to
establish operating parameter limits based on a compliance test. See
Sec. 266.106.
---------------------------------------------------------------------------

Other emissions tests may generate emissions in-between normal and
the highest compliance test emissions. An example is a compliance test
designed to demonstrate compliance with the particulate matter standard
where: (1) The air pollution control equipment is detuned; and (2) the
source measured lead and cadmium emissions even though it elected to
comply with RCRA Tier 1 feedrate limits for those metals and, thus,
does not spike those metals. We would conclude that lead and cadmium
emissions--together they comprise the semivolatile metals--are between
normal and the highest compliance test emissions. Emissions are not
likely to be as high as

[[Page 21219]]

compliance test emissions because the source did not use the test to
demonstrate compliance with emission standards for the metals (and so
did not spike the metals). However, emissions of the metals are likely
to be higher than normal because the air pollution control equipment
was detuned.
To distinguish between normal and compliance test data, we
classified emissions data for each pollutant for each test condition as
compliance test (CT); normal (N); in between (IB); or not applicable
(NA).\38\ These classifications apply on a HAP-by-HAP basis. For
example, some HAP measured during a test condition may be classified as
representing compliance test emissions for those HAP, while other HAP
measured during the test condition may be classified as representing
normal emissions. See USEPA ``Draft Technical Support Document for HWC
MACT Replacement Standards, Volume II: HWC Emissions Data Base,'' March
2004, Chapter 2, for additional details.
---------------------------------------------------------------------------

\38\ NA means the normal versus compliance test classification
is not applicable. Research testing data is an example of the type
of data that would get a NA rating.
---------------------------------------------------------------------------

D. Invitation To Comment on Data Base

As previously discussed, we updated the data base based on comments
received since it was last made publicly available. We believe the data
base used to determine today's proposed standards is complete and
accurate. However, given the complexity of the data base, we believe it
is appropriate to once again solicit comments on the accuracy of the
data. If you find errors, please submit the pages from the test report
that document the missing or incorrect entries and the cover page of
the test report as a reference. In addition, we identified several
sources that are no longer burning hazardous waste and removed their
emissions data and related information from the data base. We encourage
owners and operators of hazardous waste combustors to review our list
of operating combustors to ensure its accuracy. See USEPA ``Draft
Technical Support Document for HWC MACT Replacement Standards, Volume
III: Selection of MACT Standards and Technologies,'' March 2004.

IV. How Did EPA Select the Format for the Proposed Rule?

The proposed rule includes emission limits for dioxin/furans,
mercury, particulate matter, semivolatile metals, low volatile metals,
hydrogen chloride/chlorine gas, and carbon monoxide or hydrocarbons. We
also propose percent reduction standards for: (1) Destruction and
removal efficiency \39\ for organic HAP; and (2) total chlorine control
for hydrochloric acid production furnaces. Finally, sources would be
required to establish operating parameter limits under prescribed
procedures to ensure continuous compliance with the emission standards.
---------------------------------------------------------------------------

\39\ Please note that we propose today a destruction and removal
efficiency standard only for boilers and process heaters and
hydrochloric acid production furnaces. We are not reproposing the
destruction and removal efficiency standard in subpart EEE currently
in effect for incinerators, cement kilns, and lightweight aggregate kilns.
---------------------------------------------------------------------------

We discuss below the rationale for: (1) Selecting an emission limit
format rather than a percent reduction format in most cases; (2)
selecting a hazardous waste thermal emissions format for the emission
limit in some cases, and an emissions concentration format in others;
(3) selecting surrogates to control multiple HAP; and (4) using
operating parameter limits to ensure compliance with emission standards.

A. What Is the Rationale for Generally Selecting an Emission Limit
Format Rather Than a Percent Reduction Format?

Using emission limits as the format for most of the proposed
standards provides flexibility for the regulated community by allowing
a regulated source to choose any control technology or technique to
meet the emission limits, rather than requiring each unit to use a
prescribed method that may not be appropriate in each case. (See CAA
section 112(h), relating to authority to adopt work place standards).
Although a percent reduction format would allow flexibility in choosing
the control technology to achieve the reduction, a percent reduction
technology does not allow the option of achieving the standard by feed
control--minimizing the feed of metals or chlorine. Consequently, we
propose percent reduction standards only in special circumstances.
We are proposing a percent reduction standard for boilers and
hydrochloric acid production furnaces, i.e., a destruction and removal
efficiency standard for organic HAP, because all sources currently
comply with such a standard under RCRA and RCRA implementing rules.
Further, we do not have emissions data on trace levels of organic HAP
that would be needed to establish emission limits for particular compounds.
We also propose a total chlorine percent reduction standard as a
compliance option for hydrochloric acid production furnaces in lieu of
the proposed stack gas concentration limit because a stack gas
concentration limit may ultimately result in limiting the feed of
chlorine to furnaces with MACT emission control equipment. Given that
these furnaces produce hydrochloric acid from chlorinated feedstocks,
limiting the feed of chlorine is inappropriate. See Part Two, Section
VI.A and XII for more discussion on the total chlorine standard for
hydrochloric acid production furnaces.

B. What Is the Rationale for Selecting a Hazardous Waste Thermal
Emissions Format for Some Standards, and an Emissions Concentration
Format for Others?

We are proposing numerical emission limits in two formats:
hazardous waste thermal emissions, and stack gas emissions
concentrations. Hazardous waste thermal emissions are expressed as mass
of pollutant contributed by hazardous waste per million Btu of heat
contributed by hazardous waste. Emission concentration based standards
are expressed as mass of pollutant (from all feedstocks) per unit of
stack gas (e.g., [mu]g/dscm).
1. What Is the Rationale for the Hazardous Waste Thermal Emissions Format?
In the 1999 rule, we assessed hazardous waste feed control levels
for metals and chlorine by evaluating each source's maximum theoretical
emission concentration (MTEC) using the ``aggregate MTEC'' approach.
See 64 FR at 52854. MTEC is defined as the metals or chlorine feedrate
divided by the gas flow rate, and is expressed in [mu]g/dscm. We used
MTECs to assess feed control levels because it normalizes metal and
chlorine feedrates across sources of different sizes. Industry
stakeholders have claimed that use of MTECs to assess feed control
levels for energy recovery units (e.g., cement kilns) when establishing
floor standards inappropriately penalizes sources that burn hazardous
waste fuels at high firing rates (i.e., percent of heat input from
hazardous waste). This is because hazardous waste fuels generally have
higher levels of metals and chlorine than the fossil fuels they
displace, thus metal and chlorine feedrates and emissions may increase
as the hazardous waste firing rate increases.
Although we are not using the aggregate MTEC approach to evaluate
feed control in today's proposal, the SRE/Feed approach explained in
Part Two, Section VI.A, does assess each source's metal and chlorine
hazardous waste feed control levels. In order to avoid the hazardous
waste firing rate bias discussed above for energy recovery

[[Page 21220]]

units, we believe it is appropriate to instead assess feed control for
energy recovery units by ranking each source's thermal feed
concentration, which is equivalent to the mass of metal or chlorine in
the hazardous waste per million BTUs hazardous waste fired to the
combustion unit. This approach not only normalizes metal and chlorine
feedrates across sources of different sizes, but also normalizes these
feedrates across energy recovery units with different hazardous waste
firing rates. For example, a kiln that feeds hazardous waste with a
given metal concentration to fulfill 100% of its energy demand would be
an equally ranked feed control source when compared to an identical
kiln that fulfills 50% of its energy demand from coal and 50% from
hazardous waste with an identical metal concentration.
Similarly, it is our preference to express today's proposed
emission standards for metals and chlorine in units of hazardous waste
thermal emissions as opposed to expressing the standards in units of
stack gas concentrations. As previously discussed, hazardous waste
thermal emission standards are expressed as mass of HAP emissions
attributable to the hazardous waste per million Btu hazardous waste
fired to combustor. As with thermal feed concentration, thermal
emissions normalizes emissions across energy recovery units with
different hazardous waste firing rates. The hazardous waste thermal
emissions format addresses two concerns. First, it avoids the above
discussed bias against sources that burn hazardous waste fuels at high
firing rates. We prefer not to discourage energy recovery from
hazardous waste as opposed to potentially establishing standards that
effectively restrict the hazardous waste firing rate in an energy
recovery combustor. (See, for example, the requirement in CAA section
112(d)(2) to take energy considerations into account when promulgating
MACT standards, as well as the objective in RCRA section 1003(b)(6) to
encourage properly conducted recycling and reuse of hazardous waste).
Second, because the hazardous waste thermal emissions approach
controls only emissions attributable to the hazardous waste feed (see
discussion in following section), the rule can be simplified by not
including waivers for sources that cannot meet the standard because of
metals or chlorine contributed by nonhazardous waste feedstreams. To
ensure that hazardous waste combustors will be able to achieve the
standards if they use MACT control for metals and chlorine attributable
to the hazardous waste feed, but irrespective of metals and chlorine in
nonhazardous waste feedstreams, current MACT standards for cement and
lightweight aggregate kilns that burn hazardous waste provide
alternative standards that sources can request under a petitioning
procedure. See Sec. 63.1206(b)(9-10). These alternative standards
would be unnecessary under the hazardous waste thermal emissions
approach because, by definition, the approach controls only hazardous
waste-derived metals and chlorine.
2. Which Standards Would Use the Hazardous Waste Thermal Emissions Format?
We propose a hazardous waste thermal emissions format for mercury,
semivolatile metals, low volatile metals, and total chlorine (i.e., the
HAPs found in hazardous waste fuels) for source categories that burn
hazardous waste fuels where we have data to calculate a hazardous waste
thermal emissions limit. Cement kilns, lightweight aggregate kilns and
liquid-fuel fired boilers burn hazardous waste fuels and are thus
candidates for the hazardous waste thermal emission standards.
Incinerators and solid fuel-fired boilers are not candidates for
thermal emission standards because some sources within these source
categories do not combust hazardous waste for energy recovery, i.e.,
they burn low heating value hazardous waste for the purpose of treating
the waste.\40\ Consequently, these sources could not duplicate a
hazardous waste thermal emissions standard based on emissions from
sources that burn hazardous waste fuels, even though their stack gas
emission concentrations could be as low or lower than emissions from a
best performing source under the hazardous waste thermal emissions approach.
---------------------------------------------------------------------------

\40\ Three of the 13 solid fuel-fired boilers burn low heating
value hazardous waste for treatment.
---------------------------------------------------------------------------

We propose a hazardous waste thermal emissions format for all HAP
for which we can apportion emissions between the hazardous waste fuel
feed and other feedstreams. Under this approach, we apportion total
stack emissions between hazardous waste fuel and other feedstreams
using the ratio of the feedrate contribution from hazardous waste to
the total feedrate of the pollutant. Thus, the particulate matter,
metals, and total chlorine standards are candidates because we often
have data on hazardous waste and total feedrates of these pollutants.
We believe, however, that a hazardous waste thermal emissions
format is not appropriate for particulate matter for cement and
lightweight aggregate kilns because particulate matter emissions from
cement and lightweight aggregate kilns are primarily entrained raw
material, not ash contributed by the hazardous waste fuel. There is
therefore no correlation between particulate matter emissions and
hazardous waste thermal input rate.
In addition, please note that we could have expressed the proposed
particulate matter standard for liquid boilers in units of hazardous
waste thermal emissions since (unlike the case of kilns just discussed)
particulate matter emissions are attributable to the hazardous waste
fuel. However, for consistency, we elected to use the same format for
all the particulate matter standards. We invite comment as to whether
the particulate matter standard for liquid boilers should be expressed
in units of hazardous waste thermal emissions.
We do not have adequate data to establish hazardous waste thermal
emissions-based standards for several cases. An example is when we have
only normal feedrate and emissions data (e.g., the mercury standard for
cement kilns). We prefer to establish emission standards under the
hazardous waste thermal emissions format using compliance test data
because the metals and chlorine feedrate information from compliance
tests that we use to apportion emissions to calculate emissions
attributable to hazardous waste are more reliable than feedrate data
measured during testing under normal, typical operations.\41\ Thus, as
a general rule, we prefer to express emission standards for energy
recovery units using the hazardous waste thermal emissions format only
when we have sufficient compliance test feed data.\42\ These situations
are discussed below in more detail in Part Two, Sections VIII, IX, and
XI where we discuss the rationale for the proposed emission standards
for energy recovery units.
---------------------------------------------------------------------------

\41\ Feedrate data from testing during normal, typical
operations may not be as accurate as data from compliance testing
because of the sampling and analytical error associated with low
feedrates. In contrast, sources generally spike metals and chlorine
during compliance testing, so that measurement error is somewhat
masked by the higher feedrate values.
\42\ Two exceptions are the mercury and semivolatile metal
standard for liquid fuel-fired boilers. We propose to express this
standard in the hazardous waste thermal emissions format even though
it is based on normal test data because we do not use feedrate data
to apportion emissions in this case. Rather, we assume semivolatile
metal emissions from liquid fuel-fired boilers are attributable
solely to the hazardous waste given that these sources co-fire
hazardous waste with natural gas or, in a few cases, fuel oil.

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[[Page 21221]]

3. How Are Emissions From Other Feedstreams Regulated Under the
Hazardous Waste Thermal Emissions Format?
Under the thermal emissions format, only emissions of HAP
contributed by the hazardous waste are directly regulated by today's
proposed standards. Non-mercury metal HAP emissions from raw materials
and fossil fuels would be subject to MACT standards, even though it may
not be feasible to directly control their feedrate. We are proposing
standards for particulate matter as surrogates to control these HAP
metals contributed by raw materials and fossil fuel.

C. What Is the Rationale for Selecting Surrogates To Control Multiple HAP?

HWCs can emit a wide variety of HAP, depending on the types and
concentrations of pollutants in the hazardous waste feed. Because of
the large number of HAP potentially present in emissions, we propose to
use several surrogates to control multiple HAP. This will reduce the
burden of implementation and compliance on both regulators and the
regulated community.
1. Surrogates for Metal HAP
We are proposing to control metal HAP emissions attributable to the
hazardous waste by subjecting sources to metal and particulate matter
emission limitations.\43\ We grouped metal HAP according to their
volatility because volatility is a primary consideration when selecting
an emission control technology.\44\ We then considered the following to
identify metals that would be ``enumerated'' and directly controlled
with an emission limit: (1) The amount of available data for the metal
HAP; (2) the potential for hazardous waste to contain substantial
levels of a metal; and (3) the toxicity of the metal. Other,
``nonenumerated'' metal HAP would be controlled using particulate
matter as a surrogate.
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\43\ As discussed later, we are also propsoing particulate
matter standards to generally serve as surrogates to control
relevant metal HAP in non-hazardous waste feed streams when appropriate.
\44\ See 64 FR at 52845-47 (September 30, 1999).
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Mercury is highly volatile, especially toxic, and may not be
controllable by the same air pollution control mechanisms as the other
HAP metals, so we are proposing a standard for mercury individually.
Two semivolatile metals can be prevalent in hazardous waste and are
particularly hazardous: lead and cadmium. We group these two metals
together and propose an emission standard for these metals, combined.
The combined emissions of lead and cadmium cannot exceed the
semivolatile metal emission limit. Three low volatile metals can be
prevalent in hazardous waste and are particularly hazardous: arsenic,
beryllium, and chromium. We group these three metals together and
propose an emission standard for these metals, combined. The combined
emissions of arsenic, beryllium, and chromium cannot exceed the low
volatile metal emission limit.
The particulate matter standard generally serves as a surrogate to
control non-enumerated metals in the hazardous waste as well as a
surrogate to control relevant metal HAP in non-hazardous waste feed
streams. We generally chose not to propose numerical metal HAP emission
standards that would have accounted for all metal HAP for two reasons
(note that such an approach would be in lieu of a proposed particulate
matter standard because particulate matter is not a listed HAP). We
generally do not have as much compliance test emissions information in
our database for the nonenumerated metal HAP compared to the enumerated
metal HAP. Thus it would be more difficult to assess the control levels
for these additional metals. We also believe that a particulate matter
standard, in lieu of emission standards that directly regulate all the
metals, simplifies compliance activities in that sources would not have
to monitor feed control levels of these nonenumerated metals on a
continuous basis.
Note that particulate matter is not an appropriate surrogate where
standards are based, in part (or in whole) on feedrate control. This is
because, unlike the case where HAP metals are controlled by air
pollution control devices, HAP metal reductions in hazardous waste
feedrate are not necessarily correlated with particulate matter
reductions, i.e., hazardous waste feedrate reductions could reduce HAP
metal emissions without a correlated reduction in particulate matter
emissions. (See National Lime, 233 F. 3d at 639 noting this
possibility.) Moreover, particulate matter that is emitted generally
contain greater percentages of HAP metals when the metal concentrations
in the hazardous waste feed increase. Thus, low particulate matter
emissions do not necessarily guarantee low metal HAP emissions,
especially in instances where the hazardous waste feeds are highly
concentrated with metal HAP.
We do not believe that the proposed emission standards for
semivolatile and low volatile metals serve as adequate surrogate
control for the nonenumerated metal HAP. Compliance with the
semivolatile and low volatile metal emission standards does not ensure
that sources are using MACT back-end control devices because they could
be achieving compliance by primarily implementing hazardous waste feed
control for the enumerated metals. Thus, if a source uses superior feed
control only for the enumerated metals, the nonenumerated metal
emissions would not be controlled to MACT levels if it were not using a
MACT particulate matter control device. The proposed semivolatile and
low volatile metal standards are also inappropriate surrogates for
controlling nonmercury metal HAP in the nonhazardous waste feedstreams
for kilns and solid fuel-fired boilers for the same reason. These
sources may comply with the proposed semivolatile and low volatile
metal emission standards by implementing hazardous waste feed control.
This would not assure that the nonmercury metal HAP emissions
attributable to the nonhazardous waste feedstreams are controlled to
MACT levels. A particulate matter standard provides this assurance.
Note that we are proposing that incinerators and liquid boilers
that emit particulate matter at levels higher than the proposed
standard but do not emit significant levels of non-mercury metal HAP
can elect to comply with an alternative standard. Under the proposed
alternative standard, these sources would be required to: (1) Limit
emissions of all semivolatile metals, including nonenumerated
semivolatile metals, to the emission limit for semivolatile metals; and
(2) limit emissions of all low volatile metals, including nonenumerated
low volatile metals, to the emission limit for low volatile metals. See
Part Two, Section XVIII for more discussion on this alternative.
2. Surrogates for Organic HAP
For Phase II sources, we propose two standards as surrogates to
control emissions of organic HAP: carbon monoxide or hydrocarbons, and
destruction and removal efficiency.\45\ Both of these standards control
organic HAP by ensuring combustors are operating under good combustion

[[Page 21222]]

practices that should result in destruction of the organic HAP. Note
that boilers and hydrochloric acid production furnaces that burn
hazardous waste are currently subject to RCRA requirements that
regulate carbon monoxide or hydrocarbon emissions and destruction and
removal efficiency standard under RCRA regulations. We propose to
control dioxin/furans by a separate standard because dioxin/furan can
also be formed post-combustion in ductwork, waste heat recovery
boilers, or dry air pollution control devices (e.g., electrostatic
precipitators and fabric filters).
---------------------------------------------------------------------------

\45\ Please note that we are proposing the organic emission
standards--carbon monoxide or hydrocarbons, and desturction and
removal efficiency--for boilers and process heaters and hydrochloric
acid production furnaces only. Requirements to comply with these
standards are currently in effect under subpart EEE for
incinerators, cement kilns, and lightweight aggregate kilns. We are
not reporposing or reopening consideration of those standards in
today's notice.
---------------------------------------------------------------------------

Hydrocarbon emissions are a direct measure of many organic
compounds, including organic HAP. Carbon monoxide emissions are a more
conservative indicator of hydrocarbon and organic HAP emissions because
the presence of carbon monoxide at elevated levels is indicative of
incomplete oxidation of organic compounds. Sources generally choose to
comply with the carbon monoxide standard because carbon monoxide
continuous emissions monitors are less expensive and easier to maintain
than hydrocarbon monitors.
We also propose to use the destruction and removal efficiency
standard to help ensure boilers and hydrochloric acid production
furnaces operate under good combustion conditions. We propose to adopt
the standard and implementation procedures that currently apply to
these sources under RCRA regulations at Sec. 266.104. We propose,
however, to require a one-time only compliance requirement for
destruction and removal efficiency, unless a source changes its design
or operation in a manner that could adversely affect its ability to
meet the destruction and removal efficiency standard. Further, previous
destruction and removal efficiency testing performed under RCRA could
be used to document the one-time compliance.

D. What Is the Rationale for Requiring Compliance With Operating
Parameter Limits To Ensure Compliance With Emission Standards?

In addition to meeting emission limits, today's proposal would
require sources to establish limits on key operating parameters for the
combustor and emission control devices. Each source would establish
site-specific limits for the parameters based on operations during the
comprehensive performance test, using prescribed procedures for
calculating the limits. The operating parameter limits would reasonably
ensure that the combustor and emission control devices continue to
operate in a manner that will achieve the same level of control as
during the comprehensive performance test.
We selected the operating parameters for which sources would
establish limits because: (1) The parameters can substantially affect
emissions of HAP; (2) they are feasible to monitor continuously; (3)
they are currently used to monitor performance under the Interim
Standards Rule for incinerators, cement kilns, and lightweight
aggregate kilns that burn hazardous waste; and (4) this is the same
general compliance approach that is currently applicable to all
hazardous waste combustion sources pursuant to the RCRA emission
standard requirements.

V. How Did EPA Determine the Proposed Emission Limitations for New and
Existing Units?

A. How Did EPA Determine the Proposed Emission Limitations for New Units?

All standards established pursuant to section 112 of the CAA must
reflect MACT, the maximum degree of reduction in emissions of air
pollutants that the Administrator, taking into consideration the cost
of achieving such emission reduction, and any non-air quality health
and environmental impacts and energy requirements, determines is
achievable for each category. The CAA specifies that the degree of
reduction in emissions that is deemed achievable for new hazardous
waste combustors must be at least as stringent as the emissions control
that is achieved in practice by the best-controlled similar unit (as
noted earlier, this specified level of minimum stringency is referred
to as the MACT floor, the term used when the statutory provision was
first introduced in Congress). However, EPA may not consider costs or
other impacts in determining the MACT floor. EPA may adopt a standard
that is more stringent than the floor (i.e., a beyond-the-floor
standard) if the Administrator considers the standard to be achievable
after considering cost, environmental, and energy impacts.

B. How Did EPA Determine the Proposed Emission Limitations for Existing
Units?

For existing sources, MACT can be less stringent than standards for
new sources, but cannot be less stringent than the average emission
limitation achieved by the best-performing 12 percent of existing
sources for categories and subcategories with 30 or more sources. EPA
may not consider costs or other impacts in determining the MACT floor.
The EPA may require a control option that is more stringent than the
floor (beyond-the-floor) if the Administrator considers the cost,
environmental, and energy impacts to be reasonable.
It has been argued that EPA is limited in the level of performance
it can evaluate in assessing which are the 12 percent existing best
performing sources to standards codified in permits, or other
regulatory limitations. The argument is based on use of the term
``emission limitation'' in section 112 (d) (3), the argument being that
``emission limitation'' is a term defined in section 302 (k) to mean
``a requirement established by the State or the Administrator which
limits the quantity, rate, or concentration of air pollutants * * *''.
EPA does not accept this argument, and indeed doubts that such an
interpretation of the statute is even permissible. In brief:
(i) Statutory text indicates that MACT floors for existing sources
is to based on actual performance. Section 112 (d) (3) (A) speaks to
the actual performance of sources, and requires that the floor for
existing sources reflect actual performance. The key statutory phrase
is not just ``emission limitation'' but ``emission limitation
achieved'', a phrase referring to actual performance, not just a limit
simply set out in a permit or regulation. The floor is to be calculated
using ``emissions information'', a reference again to actual
performance. The provision likewise states that certain sources
achieving a lowest achievable emission rate (LAER) level of performance
without being subject to LAER (a regulatory limit) are not to be
considered in assessing best performers, redundant language if only
regulatory limits could be considered.
In fact, it is clear from context when Congress used the term
``emission limitation'' to refer to regulatory limits, and when it uses
the term to refer to a level of performance actually achieved. Compare
CAA section 111(b)(1)(B) (EPA is to consider ``emissions limitations
and percent reductions achieved in practice'' when considering whether
to revise new source performance standards) with section 110(a)(2)(A)
(State Implementation Plans must contain ``enforceable emission limitations'').
(ii) The argument leads to absurd and illegal results. The argument
that existing source MACT floors can only be based on regulatory limits
leads to results that are illegal, absurd, or both. Congress enacted
section 112 to assure technology-based control of HAP which had
heretofore gone unregulated due to the vagaries and glacial pace of

[[Page 21223]]

implementing the previous risk-based regime for HAP. 1 Legislative
History at 790, 860; 2 Legislative History at 3174-78, 3340-42. The
result, at the time of the 1990 amendments is that there were
widespread regulatory limits for only one of the 190 listed HAPs (lead,
for which there was a National Ambient Air Quality Standard) plus
NESHAPs for a half dozen other HAPs. Thus, ``emission limitations'', in
the sense used in the argument, did not exist for most HAPs. This would
lead necessarily to the result of no existing source floors because no
``emission limitations'' exist. This result is illegal. National Lime
v. EPA, 233 F. 3d 625, 634 (D.C. Cir. 2000). Where regulatory limits
are higher than actual performance levels, existing source floors
likewise would be higher than performance levels, a result both absurd
and illegal. Sierra Club v. EPA, 167 F. 3d 658, 662-63 (D.C. Cir.
1999). In fact, at the time of the 1999 rule for this source category
(hazardous waste combustion), RCRA regulatory limits were higher than
the level of performance achieved even by the very worst performing
source in the category (for some HAPs, by orders of magnitude). Yet
under the argument, the floor for existing sources would have to be
higher than even this worst performing single source.
(iii) Legislative History shows that Congress intended the existing
source floor to reflect actual best performance. The legislative
history to the MACT floor provision for existing sources likewise makes
clear that the standard was to reflect actual performance, not
regulatory limits. 2 Legislative History pp. 2887, 2898; 3353; 1
Legislative History p. 870. The legislative history to the parallel
provision for municipal waste combusters in section 129(a)(2) (which
floor requirement reads identically to section 112(d)(3)) is equally
clear, stating that the floor for such sources is to reflect emission
limitations which either have been achieved in practice or are
reflected in permit limitations, whichever is more stringent. See
Sierra Club v. EPA, 167 F. 3d at 662 (noting this legislative history.)
(iv) The argument has already been rejected in litigation. The D.C.
Circuit, in the three cases dealing with MACT floors, has held in all
three cases that the floor standard must reflect actual performance.
Sierra Club, 167 F. 3d at 162-63; National Lime, 233 F. 3d at 632;
Cement Kiln Recycling Coalition, 255 F. 3d at 865-66.
For these reasons, we reject the argument that existing source
floors are compelled to reflect only regulatory limits. Such limits may
be a permissible means of establishing existing source floors, but only
if regulatory limits ``are a reasonable means of estimating the
performance of the top 12 percent of [sources] in each [category or
subcategory].'' Sierra Club, 167 F. 3d at 661.
Somewhat ironically, there is a regulatory limit which is relevant
in establishing floors for incinerators, cement kilns and lightweight
aggregate kilns. The interim standards fix a level of performance for
all of these sources. Thus, any floor standard can be no less stringent
than this standard (see National Lime 233 F. 3d at 640 (reason for
which a level of performance is being achieved is irrelevant in
ascertaining MACT floors)). Based on actual performance, however,
floors may be more stringent.

VI. How Did EPA Determine the MACT Floor for Existing and New Units?

We followed five basic steps to calculate the proposed MACT floors.
First, we determined which MACT methodology approach is most
appropriate to apply to the given pollutant for each source category.
Second, we selected which of the available emissions data best
represent each source's performance. Third, we evaluated whether it is
appropriate to issue separate emissions standards for various
subcategories. Fourth, we identified the best performing sources based
on the chosen methodology and data. Finally, we calculated floor levels
for new and existing sources. The following sections include a
description of each of these steps. Please note that we are also
proposing to invoke CAA section 112(d)(4) to establish risk-based
standards on a site-specific basis for total chlorine for hazardous
waste combustors (except for hydrochloric acid production furnaces).
Under the proposed approach, sources may elect to comply with either
risk-based standards or section 112(d) MACT standards. See Part Two,
Section XIII for more details.

A. What MACT Methodology Approaches Are Used To Identify the Best
Performers for the Proposed Floors, and When Are They Applied?

A MACT methodology approach is a set of procedures used to define
and identify the best performing sources consistent with CAA section
112(d)(3). We have developed and used the following three different
MACT methodologies to identify the best performing sources for the full
suite of proposed floor standards for new and existing sources: (1)
System Removal Efficiency (SRE)/Feed approach; (2) Air Pollution
Control Technology Approach; and (3) Emissions-Based approach. These
three methodologies, together with their rationales and when they are
used, are described in the following sections. Note that each
methodology described below assesses best performing sources for each
pollutant or pollutant group independently, often resulting in
different best performers for each pollutant. For a more detailed
description of these methodologies and when they are applied, see USEPA
``Draft Technical Support Document for HWC MACT Replacement Standards,
Volume III: Selection of MACT Standards,'' March 2004, Chapters 7 through 15.
1. What Is SRE/Feed Approach, and When Are We Proposing To Apply It?
The SRE/Feed MACT approach defines best performers as those sources
with the best combined front-end hazardous waste feed control and back-
end air pollution control efficiency as defined by our ranking
procedure. The approach is applicable to HAP whose emissions can be
controlled by controlling the hazardous waste feed of the HAP: metals
and chlorine.\46\
These two parameters--feedrate of metals and chlorine in hazardous
waste, and performance of the emission control device measured by
system removal efficiency \47\ determine emissions of metals and
chlorine contributed by the hazardous waste feed. Back-end air
pollution control is evaluated by assessing each source's pollutant
system removal efficiency, which is a measure of the percentage of HAP
that is emitted compared to the amount fed to the unit. In identifying
system removal efficiency as a measure of best performing, the Agency
is rejecting the notion that ``best performing'' must mean a source
with the lowest absolute rate of emission of a HAP. A source emitting
300 pounds of a HAP, but removing that HAP at a rate of 99.9% from its
emissions, can logically be considered a better performing source than
one emitting 100 pounds of the same HAP but

[[Page 21224]]

removing it at an efficiency of only 50 percent.
---------------------------------------------------------------------------

\46\ The particulate matter standard is used as a surrogate to
control nonmercury metal HAP in the nonhazardous waste feedstreams
and to control the nonenumerated metals in the hazardous waste. As
explained Part Two, Section VI.A.2.b., control of ash feed may not
be an effective technique to control metal HAP. Thus, we do not use
the SRE/Feed approach to identify floor levels for particulate
matter since ash feed control may not be a reliable indicator of performance.
\47\ Although system removal efficiency measures primarily the
performance of the back-end emission control device, it also
measures any other internal control mechanisms, such as partitioning
of metals to the product in a cement or lightweight aggregate kiln.
---------------------------------------------------------------------------

Use of feedrate and system removal efficiency as measures of
performance is appropriate because these parameters incorporate the
effects of the myriad factors that can indirectly affect emissions,
such as level of maintenance of the combustor or emission control
equipment, and operator training, as well as design and operating
parameters that directly affect performance of the emission control
device (e.g., air to cloth ratio and bag type for a fabric filter; use
of a power controller on an electrostatic precipitator). For example,
an incinerator with a well-designed and operated fabric filter would
have a higher performance rating measured by system removal efficiency
than an identical incinerator equipped with the same fabric filter
which is, in addition, poorly maintained because of inadequate operator
training. Also, although feedrate of metals and chlorine in
nonhazardous waste feedstreams such as raw materials and fossil fuels
fed to a cement kiln can affect HAP emissions substantially, those
emissions can be feasibly controlled only by back-end control (measured
here by system removal efficiency).\48\ This is because neither fuel
switching nor raw material switching is practicable for production
facilities such as cement and lightweight aggregate kiln facilities.
Thus, feedrate of metals and chlorine contributed by the hazardous
waste--the only controllable feed parameter for these sources--is an
appropriate metric.
---------------------------------------------------------------------------

\48\ See discussion in the proposed lime production MACT
explaining why neither raw material or fossil fuel substitution are
available means of controlling the feedrate of HAP. See 67 FR at
78059-61 (Dec. 20, 2002). The rationale for lime kilns also applies
to cement and lightweight aggregate kilns. Briefly, in the context
of floor control: (1) A kiln's principle raw materials (limestone
for cement kilns and clay for lightweight aggregate kilns) are not
available to other kilns; and (2) we are not aware of raw materials,
or sources of coal or oil, that have characteristic and consistent
(low) concentrations of HAP. In the context of beyond-the-floor
control, additional issues include: (1) The cost of transporting raw
materials with lower levels of HAP (if it were feasible to identify
them) would be prohibitive; and (2) although switching from coal or
oil to natural gas would reduce the feedrate of HAP, the limitations
of the natural gas distribution infrastructure are such that natural
gas is not readily available to many sources.
---------------------------------------------------------------------------

For incinerators and solid fuel-fired boilers, feed control is
evaluated by assessing each source's hazardous waste pollutant maximum
theoretical emission concentration.\49\ Feed control for energy
recovery units (cement kilns, lightweight aggregate kilns, and liquid
fuel-fired boilers) are evaluated by assessing each source's hazardous
waste pollutant thermal feed concentration when possible (i.e., when
EPA has sufficient data to make the calculation).
---------------------------------------------------------------------------

\49\ In the 1999 rule, we developed the term maximum theoretical
emissions concentration to compare metals and chlorine feed control
levels across sources of different sizes. See 64 FR at 52854.
Maximum theoretical emissions concentration is defined as the metals
or chlorine feedrate divided by the gas flowrate, and is expressed
in terms of [mu]g/dscm. See Part Two, section IV.B.1 for more
discussion on how we normalize feedrates and emissions across sources.
---------------------------------------------------------------------------

We rank each source's pollutant hazardous waste feed control level
against all the other source's feed control level, assigning a relative
rank of 1 to the source with the lowest, i.e., best, feed control level
and assigning the highest ranking score to the source with the highest,
i.e., worst, feed control level. We do the same with each source's
system removal efficiency. We rank each source's pollutant system
removal efficiency against all the other sources' system removal
efficiencies, assigning a relative rank of 1 to the source with the
highest, i.e., best, system removal efficiency and assigning the
highest ranking score to the source with the lowest, i.e., worst,
system removal efficiency. We then add each source's feed control
ranking score and system removal efficiency ranking score to yield an
SRE/Feed aggregated score. Each source's aggregated score is arrayed
and ranked from lowest to highest, i.e., best to worst, and, for
existing sources, the best performers are the sources at the 12th
percentile aggregate score and below. Floor levels are then calculated
by using the emissions from these best performing sources. The SRE/
Feed-based standards are expressed in units of hazardous waste thermal
emissions when possible for energy recovery units.
Please note that the SRE/Feed approach can occasionally identify a
floor level for new sources that is higher than the floor level for
existing sources, as discussed below in Sections VII to XII. This is
because the source with the best SRE/Feed aggregate score, and thus,
the single best performing source under this approach, does not always
achieve the lowest emissions among the best performing sources after
accounting for emissions variability. In two cases only, the emissions
for the best performing SRE/Feed source, after accounting for emissions
variability, are higher than the average of the best performing five
(or 12%) of sources--the floor for existing sources--after considering
emissions variability.\50\ For example, the single best performing SRE/
Feed source may have both higher emissions and run variability than
other best performing sources. This source's emissions are averaged
with the other best performers to identify the floor level, and its run
variability is dampened when we calculate the floor for existing
sources by pooling run variability across the best performing sources.
When the single best performer's emissions are evaluated individually,
however, a relatively high run variability is not dampened. In those
few situations where the best performing SRE/Feed source has higher
emissions, after accounting for emissions variability (i.e., the
potential floor for new sources), than the floor for existing sources,
we default to the floor for existing sources to identify the floor for
new sources. We request comment on whether it would be more appropriate
to identify the floor for new sources under the SRE/Feed approach by
selecting the source with the lowest emissions among the best
performing existing sources, after considering run variability, rather
than the lowest SRE/Feed aggregate score.
---------------------------------------------------------------------------

\50\ This occurred for the low volatile metal standard for
cement kilns and the mercury standard for solid-fuel fired boilers.
---------------------------------------------------------------------------

The SRE/Feed methodology is generally applied only to HAP where we
can accurately assess each source's relative hazardous waste feed
control and back-end air pollution control: mercury, semivolatile
metals, low volatile metals, and total chlorine. Dioxin/furans are not
considered to be feed control HAP because they generally are not fed
into the combustor; rather, they are formed in the combustor and post
combustion. Also, whereas particulate matter (for all source
categories) and total chlorine (for hydrochloric acid production
furnaces) could be considered to be feed-controlled and back-end
controlled pollutants, we do not believe it is appropriate to assess
feed control as a control mechanism for these situations for reasons
discussed below in Section 2 (largely dealing with the inability to
control HAP in raw material feed or in fossil fuel). As a result, we
did not apply the SRE/Feed approach to these pollutants.
Finally, the SRE/Feed approach is also not applied when we do not
have sufficient compliance test data to accurately assess each source's
relative back-end control efficiency. This occurs in a limited number
of circumstances when the majority of the emissions data reflect normal
operations. The mercury and semivolatile metal standard for liquid
boilers are examples of when we do not believe we possess sufficient
data to accurately assess each source's back end control efficiency
because we are concerned that the normal feed data are too sensitive to
sampling and measurement error to provide a reliable

[[Page 21225]]

system removal efficiency that would be used reliably in the ranking
procedure. Our preference is to use system removal efficiencies that
are based on compliance testing because sources typically spike the
pollutant feeds during these compliance tests to known elevated levels,
resulting in calculated system removal efficiencies that are more reliable.
2. What Are the Air Pollution Control Technology Approaches, and When
Are They Applied?
The air pollution control technology approach is applied in two
situations where we consider it inappropriate to directly assess
hazardous waste feed control--the particulate matter standard for all
sources categories and the total chlorine standard for hydrochloric
acid production furnaces. We apply slightly different methodologies to
each of these situations, as discussed below.
a. What Methodology Was Used To Identify the Best Performing
Sources for the Particulate Matter Floors? The best performing sources
for the proposed particulate matter floor levels are determined using a
methodology that is conceptually similar to that used in the Industrial
Boiler MACT proposal. See 68 FR at 1660. We call this methodology the
``air pollution control technology'' approach because it defines best
performers as those that use the best type of back-end air pollution
control technology.
This methodology first assesses all the back-end control
technologies used by all the sources within the source category, and
ranks the general effectiveness of these control technologies from best
to worst using engineering information and principles. For example, for
particulate matter control, high efficiency particulate air filters may
be ranked as the best air pollution control device, followed by
baghouses, electrostatic precipitators, and high energy wet scrubbers.
In this example, all sources equipped with a high efficiency
particulate air (i.e., HEPA) filter would get the best ranking (e.g.,
``1''), and all sources equipped with high energy wet scrubbers would
get the worst ranking (e.g., 4).
The sources are arrayed and ranked from best to worst based on
their control technology rankings. For existing sources, MACT control
is defined as the control technology or technologies used by the best
12 percent of these sources. For example, using the previous
particulate matter control rankings, if more than 12 percent of the
sources within the source category were using high efficiency
particulate air filters, then MACT control would be defined to be high
efficiency particulate air filters. If 10 percent of all the sources
were equipped with high efficiency particulate air filters, and 4
percent were equipped with baghouses, then MACT control would be
defined as both high efficiency particulate air filters and baghouses.
After the MACT control technology or technologies are determined,
the MACT floor levels are calculated using emissions data from those
sources using MACT control. See Part Two, Section IV.D.3 for more
discussion on the ranking procedure that is used to identify the best
performing sources under this approach. Also see USEPA ``Draft
Technical Support Document for HWC MACT Replacement Standards, Volume
III: Selection of MACT Standards,'' March 2004, Chapter 9, for more
information. This methodology consequently focuses on performance of
the best pollution control device, but does not assess further control
that might result from lower HAP feedrates.\51\
---------------------------------------------------------------------------

\51\ This methodology does not, however, expand the MACT pool to
include sources with emission levels greater than those of the best
12 per cent of performers using MACT control (the approach the Court
in CKRC held was inadequately justified as representing the 12
percent of best performing sources).
---------------------------------------------------------------------------

We believe it is appropriate to identify the best performing
sources using particulate matter emissions from those using MACT back-
end control without considering hazardous waste ash feedrate control.
For cement kilns, lightweight aggregate kilns, and solid fuel-fired
boilers, particulate emissions are largely contributed by non-hazardous
waste feedstreams (i.e., entrained raw material for kilns, and
entrained coal ash for solid fuel-fired boilers). Thus, hazardous waste
feed control is an inappropriate factor to consider when assessing
particulate matter control efficiency. Assessment of, and control of,
total ash feedrate (i.e., hazardous waste plus raw materials and
nonhazardous waste fuel ash feed) would also be inappropriate because,
as discussed below, total ash feedrate may not be a reliable indicator
of a source's emission control level for metal HAP, and could
inappropriately result in a methodology that assesses (and controls)
raw material and/or nonhazardous waste fuel input.
Although particulate matter emissions for incinerators and liquid
fuel-fired boilers are more directly related to these devices'
hazardous waste ash feedrate, the hazardous waste ash feedrate for
these sources may not be a reliable indicator of a source's feedrate
(and emissions) of nonenumerated metal HAP given that the ash feed into
the combustor may contain high or low concentrations of regulated metal
HAP. A source that feeds low levels of ash thus may not be a best
performing source for metal HAP emissions if its metal concentration
levels in its ash are relatively high. Such a source could be
identified as a best performing source because its particulate matter
emissions and ash feed is low, even though its metal HAP emissions are
relatively high. This result would also inappropriately assess and
control elements of the hazardous waste ash feed that are not regulated
HAP (e.g., silica input). For these reasons, using the air pollution
control technology approach to establish particulate matter floors
without explicitly considering ash feedrate is appropriate since it
focuses on the control technology (i.e., back-end air pollution control
technology) that is known to control metal HAP emissions.\52\
---------------------------------------------------------------------------

\52\ Please note that, although we do not explicitly consider
ash feedrate when establishing the particulate matter floor, ash
feedrate is an appropriate and necessary compliance assurance
parameter for incinerators and liquid fuel-fired boilers where ash
from hazardous waste feedstreams contribute substantially (or
entirely) to particulate emissions.
---------------------------------------------------------------------------

b. What Methodology Is Used To Identify the Best Performing Sources
for the Total Chlorine Floor for Hydrochloric Acid Production Furnaces?
We apply the air pollution control technology approach to total
chlorine for hydrochloric acid production furnaces differently. For
this floor calculation, we are proposing to use the same methodology
that the Agency used for the hydrochloric acid production MACT final
rule for sources that do not burn hazardous waste. See 68 FR at 19076.
This methodology defines best performers as those sources with the best
total chlorine system removal efficiency. Each source's total chlorine
system removal efficiency is arrayed and ranked from highest to lowest,
and the best existing performers are the sources at the 12th percentile
ranking and below. We calculate the system removal efficiency floor
level using the total chlorine system removal efficiencies achieved by
these best performing sources. Consistent with the non hazardous waste
hydrochloric acid production MACT final rule, we also propose to allow
sources to comply with a total chlorine stack gas concentration limit
that is calculated by multiplying the highest hazardous waste chlorine
maximum theoretical emission concentration in the data base by 1 minus
the MACT system removal efficiency. This ensures that a source

[[Page 21226]]

complying with the alternative concentration-based standard would not
emit higher levels of total chlorine than a source equipped with wet
scrubbers that achieve MACT system removal efficiency. We believe this
alternative standard is appropriate because it gives sources the option
of complying with the floor by implementing hazardous waste feed control.\53\
---------------------------------------------------------------------------

\53\ A source could operate with a ``less than MACT'' system
removal efficiency provided that it controls its hazardous waste
chlorine feed levels such that its emissions are lower than the
emission standard.
---------------------------------------------------------------------------

We believe this methodology is appropriate even though it does not
directly assess hazardous waste total chlorine feed control because
these sources are in the business of feeding highly chlorinated
hazardous wastes so that they can recover the chlorine for use in their
production process. Requiring these sources to minimize hazardous waste
chlorine feed would be directly regulating their raw material and would
directly affect their ability to produce their product. Again, in this
situation, we believe it is appropriate to use a methodology approach
that solely focuses on back-end control, since back-end control assures
removal of the target pollutant without inappropriately requiring a
source to control feedstreams in a manner that affects its ability to
produce its intended product.
3. What Is the Emissions-Based Approach, and When Is It Applied?
The emissions-based approach defines best performers as those
sources with the lowest emissions in our database. We array and rank
each source's pollutant emission levels from lowest to highest. The
best existing performers are the sources at the 12th percentile ranking
and below. We calculate floor levels using the emission levels from
these best performing sources. We express the emissions-based standards
in units of hazardous waste thermal emissions when possible for energy
recovery units, and use the approach whenever the SRE/Feed or air
pollution control technology approaches are not used. Specifically, we
use the emissions-based approach for the dioxin/furan floors for all
source categories, and for the mercury and semivolatile metal floors
for liquid fuel-fired boilers.
The SRE/Feed and air pollution technology-based approaches cannot
be used for the dioxin/furan floors because dioxin/furans are generated
in the combustor or post-combustion within the air pollution control
device. Since dioxin/furans are generally not fed to the units, the
SRE/Feed methodology would not properly assess dioxin/furan emission
control performance. In theory, the technology-based approach for
particulate matter could be applied to the dioxin/furan floors.
However, such a technology approach would, for the most part, identify
the same best performers as the emissions-based approach because there
is only one primary control technology being used by all the sources--
temperature control at the inlet to the dry air pollution control device.
The SRE/Feed approach cannot be used for the mercury and
semivolatile metal floors for the liquid fuel-fired boilers because we
do not have sufficient compliance test data to accurately assess each
source's back-end control efficiency. The technology-based approach is
also not appropriate because sources within this source category
control these HAP both by feed control and by back-end control. As a
result, a methodology that considers only one of the two primary
control techniques may not be appropriate.
4. Why Doesn't EPA Simply Apply the Emissions-Based Approach to All
Source Categories and HAP?
Under the most simplistic interpretation of CAA 112(d), we would
apply the emissions-based approach to all source categories and HAP in
calculating floors for existing sources. We considered proposing this
option. As described later in Part Two, Section VI.G, it was one of
three options for which we conducted a complete economics analysis. We
discuss below, however, why we believe the air pollution control
technology and SRE/Feed approaches more reasonably ascertains the
performance of the average of the best 12 percent of existing sources.
a. Why Do We Prefer the SRE/Feed Approach Over the Emissions-Based
Approach? We believe the SRE/Feed approach is a reasonable and
appropriate MACT methodology for the hazardous waste combustion source
categories because it better estimates the performance of the average
of the 12 percent best performing sources, and (as a necessary
corollary) assures that the floor standards would be achievable by such
sources. As previously discussed, we apply the SRE/Feed approach to HAP
that are actively controlled (via floor controls) by both hazardous
waste feed control and back-end air pollution control. There are only
two ways to control emissions of these HAP from these sources--limit
the feedrate of metal and chlorine and remove them prior to venting the
exhaust gas out the stack. These two control mechanisms are used
simultaneously by all sources in this category at varying levels.
We do not believe the lowest emission levels in our data base in
fact represent the full range of emissions achieved in practice by the
best performing sources. Indeed, it would be unlikely if this were the
case, since these data are necessarily ``snapshots'' of emissions from
the source, obtained in one-time testing events.\54\ Notwithstanding
that such testing seeks to encompass much of the variability in system
performance, no single test can be expected to do so. Thus, inherent
variability such as feedrate fluctuation over time due to production
process changes, uncertainties associated with correlations between
operating parameter levels and emissions, precision and accuracy
differences in different testing crews and analytical laboratories, and
changes in emission of materials (SO2 being an example) that
may cause test method interferences. See generally 64 FR at 52857and
52587-59.
---------------------------------------------------------------------------

\54\ One-time testing events, however, are a necessity because
Continuous Emission Monitors still do not exist for most of the HAPs
emitted by these sources.
---------------------------------------------------------------------------

An emissions-based approach for cement kilns, lightweight aggregate
kilns, and solid fuel-fired boilers that assesses performance based on
stack gas concentrations (as opposed to hazardous waste thermal
emissions) may not appropriately estimate the performance of the
average of the 12 percent best performing sources given that those best
performers may have low emissions in part because their raw material
and/or fossil fuels contained low levels of HAP during the emissions
test. We do not believe feed control of HAP in raw material and fossil
fuel should be assessed as a MACT floor control primarily because it
could result in floor levels that are not replicable by the best
performing sources, nor duplicable by other sources. See Part Two,
Section VI.A.1.
Moreover, although the emissions-based approach is not facially
inconsistent with section 112 of the Act, there are serious questions
as to whether its applicability here leads to limits that could be
achieved even by the average of the best performing sources (under the
emissions-based approach). The alternative emissions-based floor
Options 1 and 2 discussed in Part Two, Section VI.G result in floor
levels across all HAP that are achievable simultaneously by fewer than
6% of the sources for the cement kiln, incinerator, and liquid fuel-
fired boiler source

[[Page 21227]]

categories.\55\ See USEPA ``Draft Technical Support Document for HWC
MACT Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapters 10 and 19, for a summary of the simultaneous
achievability analysis. A reason the floors which would result from
this methodology are so low is that there already have been at least
one and, for many of the sources, two rounds of regulatory reduction of
emissions from these sources (under the RCRA rules, and then under the
Interim Standards MACT rules for incinerators and kilns). The
emissions-based approach thus yields results more akin to new source
standards, confirmation being that the levels are not even achievable
as a whole by the average of the 12 percent best performing sources.
The simultaneous achievability of today's proposed floors, for which we
use the SRE/Feed approach for certain HAP preferentially over the
emissions-based approach, is substantially better (but not dramatically
more than 6%) for cement kilns and liquid fuel-fired boilers than the
achievability under the emissions-based approach.
---------------------------------------------------------------------------

\55\ Simultaneous achievability percentages for lightweight
aggregate kilns, solid fuel-fired boilers, and hydrochloric acid
production furnaces must be interpreted differently given that there
are significantly fewer than 30 sources within these source
categories. As a result, we believe that the emission standards
should be simultaneously achievable by at least two or three sources
for these source categories given that CAA 112(d) defines best
performing sources as the average of the best five sources.
---------------------------------------------------------------------------

There are other reasons why the emissions-based approach results in
such low simultaneous achievability percentages. If the emissions-based
approach is applied to feed-controlled HAP, the best performers are
defined as those sources that are either: (1) The lowest feeders; (2)
the best back-end controlled units; or (3) the best combination of
front-end control or back-end control. The emissions-based approach
selects the lowest emitters from the previous three categories and does
not necessarily account for the full range of emissions that are
achieved in practice by well designed and operated feed control units,
well designed and operated back-end controlled units, or well designed
and operated combination of both front-end and back-end controlled
units. As explained below, the SRE/Feed methodology better accounts for
the range of emissions from these well designed and operated sources.\56\
---------------------------------------------------------------------------

\56\ Note, however, that many of the best performing sources for
the SRE/Feed approach are the same as those for emissions-based
approach, primarily because there is a good correlation between the
SRE/Feed aggregated ranking score and emissions in that the emission
levels generally increase as the as the aggregate ranking score increases.
---------------------------------------------------------------------------

For example, assume we have 100 sources in a hypothetical source
category, and source A is the 5th best feed controlled source and the
30th best back-end controlled source. Source B, on the other hand, is
the 30th best feed controlled source and the 5th best back-end
controlled source. The SRE/Feed ranking procedure would score these two
sources equally, even though their emissions may be different. Let's
also assume that these two sources are among the best performers for
the SRE/Feed approach. We would not expect their emission levels to be
dramatically different under the SRE/Feed approach because source A is
a superior front-end controlled source with a relatively poorer back-
end control device, and source B is a superior back-end controlled
source with relatively poorer feed control. Even though sources A and B
do not have the same emissions, they are both considered to be well
designed and operated sources because they both use a superior
combination of front-end and back-end control. The difference in
emissions merely reflects the range of emissions from well designed and
operated sources.
If the emissions-based approach was applied in the source A and B
example, the source with the higher emissions would have a worse
emission ranking, and thus may not be identified as a best performer.
Thus, even though we would consider this higher emitting source under
the SRE/Feed approach to be a well-designed and operated source, it
would not be capable of achieving the calculated floor level. We
believe this outcome may be problematic, for example, because sources
that are already operating with a well-designed and operated back-end
control unit should not have to upgrade its back-end control technology
simply because it is not achieving a floor level driven, in part, by
other sources within the source category that are implementing lower
feed control rates that are impractical for it to achieve.\57\ It may
be questionable to require these well controlled back-end units to
implement better feed control to achieve this emission-based floor
level because: (1) they may not be capable of implementing feed control
without sending/diverting the waste elsewhere--yet these units are
providing a needed and required service in treating hazardous waste;
and (2) it could be argued that hazardous waste containing high levels
of metals and chlorine should in fact be treated in the well-designed
and operated back-end controlled units (see RCRA sections 3004 (d) to
(m), requiring advanced treatment of hazardous waste before the waste
can be land disposed).
---------------------------------------------------------------------------

\57\ Moreover, the superior low metal and chlorine feedrates
that on-site incinerators and boilers are ``achieving'' may simply
reflect the composition of the waste generated by the manufacturing
operation.
---------------------------------------------------------------------------

Similarly, sources that are already achieving superior feedrate
control should not necessarily have to upgrade their feedrate control
further simply because they are not achieving a floor level driven, in
part, by sources with superior back-end control. Improving already
superior feedrate control may be problematic simply because they may
not be capable of implementing additional feed control (e.g., source
reduction) at their facility, or having generators implement further
feedrate control. EPA believes that hazardous waste feed control is an
important element of what constitutes ``best performing'' sources from
this source category, and does not wish to structure the rule to
discourage the practice by developing standards which do not directly
take this means of control into account. See CAA section 112(d)(2)(A)
(feed control is an explicit means of achieving MACT); and see also the
pollution prevention and waste minimization goals of both the CAA
(sections 112(d) (2) and 101(c) and RCRA (section 1003(b)). The SRE/
Feed approach thus better preserves the opportunity for sources to
achieve the floor levels if they are using either superior front-end
control or back-end control (or superior combination of both). At the
same time, it addresses both means by which sources in this category
can control their HAP emissions: hazardous waste feed control and back-
end air pollution capture through control technology.
The example in the previous paragraph of the source using superior
feed control is clearly applicable to incinerators and boilers that
combust hazardous waste. These are somewhat unique source categories in
that they are comprised of many different industrial sectors that may
not be capable of achieving/duplicating the same metal and chlorine
feedrate control levels of other sources within their respective source
category given that hazardous waste feed control levels are directly
influenced by amount of HAP that are generated in their specific
production process. Similarly, other sources that comprise commercial
hazardous waste combustors (i.e., kilns and commercial incinerators)
are subject to the feed control levels that are governed

[[Page 21228]]

primarily by third parties (i.e., the generators or fuel blenders). The
emissions-based approach identifies the best performers as those
sources with the lowest emissions and does not consider differences in
emission characteristics across all the industrial sectors that combust
hazardous waste. We contemplated whether we should assess if
subcategorization is appropriate based on the various industrial
sectors that combust hazardous waste. We believe, however, that such an
assessment would be difficult given the vast number of industrial
sectors that generate hazardous waste which is treated by combustion.
The emissions-based approach could be identifying a suite of floor
levels across HAP that would require sources to operate at feedrate
control levels in the aggregate that are in theory achieved by few, if
any, well-operated and designed feed controlled sources. For example,
the best performing sources for the emissions-based approach for the
incinerator semivolatile and low volatile metal floors are entirely
different. This may occur because sources have different relative feed
control levels for mercury, semivolatile metals, low volatile metals,
and total chlorine (e.g., a source could have superior semivolatile
metal feed control but only moderate low volatile metal feed control).
Finally, the emissions-based approach may result in low
simultaneous achievability percentages because a back-end control
technology for one pollutant may not control the emissions of another
pollutant as efficiently. For example, wet air pollution control
systems may control total chlorine emissions very well, but are not as
efficient at limiting particulate matter emissions when compared to a
baghouse. Thus, best performers under the emissions-based floor
approach for total chlorine could be driven by sources with wet air
pollution control systems, and the particulate matter floor could be
driven by sources equipped with baghouses, resulting in a combined set
of floors that are conceivably achieved by few sources, a result
confirmed, as noted above, in that less than 6% of existing sources
would be achieving floor standards developed using the emission-based
approach.\58,\ \59\
---------------------------------------------------------------------------

\58\ Although the SRE/Feed approach does not directly address
this issue within the methodology, the simultaneous achievability of
the SRE/Feed-based floors is substantially better (but not
dramatically more than 6%) for cement kilns and liquid fuel-fired
boilers than the achievability under the emissions-based approach.
\59\ Note that we considered using a floor methodology that
simultaneously assesses all the pollutant emissions from each
source. This methodology would define best performers as those
sources with the best aggregate emissions across all (or a subset of
all) the HAP and would perhaps more directly achieve the goal of
obtaining a full suite of emission standards that are achievable by
at least 6% of the sources. We rejected this approach in the 1999
rule, since it could potentially result in least-common denominator
source levels. See 64 FR at 52856. However, at least for
incinerators and kilns, there is less potential concern with such a
result because the Interim Standards have already reduced sources'
emissions of all HAP considerably and the Interim Standards cap the
level of floors for these sources. Nonetheless we may not have
enough complete emissions information for all HAP for many source
categories to adequately assess enough source's true ``aggregate
emissions.'' See Section VI.G.
---------------------------------------------------------------------------

We thus believe that using the SRE/Feed approach preferentially
over the emissions-based approach and technology based approach is
appropriate because use of the SRE/Feed approach results in floor
levels that better reflect the range of emissions from well-designed
and operated sources and also results in floor levels across all HAP
that are achievable simultaneously by at least 6 percent of the sources
within each source category.
b. Why Do We Prefer the Air Pollution Control Technology Approach
Over the Emissions-Based Approach? As previously discussed, we apply
the air pollution control technology approach in two situations where
we consider it inappropriate to directly assess hazardous waste feed
control using an SRE/Feed type approach: the particulate matter
standard for all source categories; and, the total chlorine standard
for hydrochloric acid production furnaces. We discuss below why the
emissions-based approach is not our preferred methodology for these standards.
For particulate matter, the emissions-based approach identifies the
lowest emitters as best performers, irrespective of the types of
controls that were used. This would not necessarily reflect emissions
that are in fact capable of being achieved by sources using MACT back-
end control technology as defined by the air pollution control
technology approach because, as discussed above, our data are
``snapshots'' of emissions from each source, obtained in one-time
testing events. As a result, the particulate matter floors that are
based on the emissions-based approach would not necessarily account for
inherent variability such as ash feedrate fluctuation over time due to
production process changes,\60\ uncertainties associated with
correlations between operating parameter levels and emissions,
precision and accuracy differences in different testing crews and
analytical laboratories, and changes in emission of materials (SO
2 being an example) that may cause test method
interferences. The air pollution control technology approach may better
account for this inherent variability because it assesses the emissions
ranges from those sources that utilize the defined back-end MACT
control devices, as opposed to merely selecting the lowest emitters
irrespective of the type of control it uses.
---------------------------------------------------------------------------

\60\ The emissions-based approach may not account for
particulate matter emissions variability factors that are
attributable to factors other than MACT control. For example, two
sources with identical air pollution control devices could have
different particulate matter emission concentrations merely because
they process different types and amounts of raw material and/or
nonhazardous waste fuels. From a MACT perspective, the source with
the higher emissions would not be a poorer performer because feed
control of raw material and nonhazardous waste fuels are not MACT
floor controls.
---------------------------------------------------------------------------

Also, using the emissions-based approach for incinerators and
liquid boilers (for the particulate matter standard) and hydrochloric
acid production furnaces (for the total chlorine standard) is not our
preferred approach because it assesses in part, hazardous waste ash and
chlorine feed control. As discussed above, the emissions-based approach
defines best performers as those sources with the lowest emissions, and
thus inherently accounts for and assesses hazardous waste ash and
chlorine feed control in that sources with lower ash feedrates and
chlorine feedrates may have lower emissions.\61\ This is not our
preferred way of establishing floors for these HAP for the reasons
discussed above in Section A.2.
---------------------------------------------------------------------------

\61\ The best performers identified by the air pollution
technology approach are less likely to be driven by low ash feeding
facilities for the particulate matter standard because all the
sources equipped with MACT-defined back-end control devices
typically feed high levels of ash, thus we believe particulate
matter emission levels from these sources are more a function of the
air pollution control device control efficiency rather than the ash
feed levels.
---------------------------------------------------------------------------

B. How Did EPA Select the Data To Represent Each Source When
Determining Floor Levels?

After we determine which MACT methodology is appropriate for a
given pollutant and source category, we select which of the available
emissions data to use for each source to: (1) Determine if
subcategorization is warranted; (2)

[[Page 21229]]

identify the best performing sources; and (3) calculate the floor
levels. Our emissions data base is complex because it includes, in
part, compliance test data, emissions data that is representative of
the normal operating range of the source, and, for the Phase I sources,
multiple emission test data that have been collected over a number of
years. See Part Two, Section III for more discussion on data base issues.
We follow a general ``data hierarchy'' to determine which of these
data types to use to represent each source's performance (with the
performance being reassessed for each HAP). First, we prefer to
explicitly use compliance test data rather than data representative of
normal operations because compliance test data best reflect the upper
range of emissions from each source and thus best accounts for day-to-
day emissions variability. Use of compliance test data allows us to
express emission floors as ``short-term limits'' (e.g., hourly or
twelve hour rolling averages), which is consistent with the current
interim MACT standard format for incinerators, cement kilns, and
lightweight aggregate kilns. Short-term limits are also consistent with
the RCRA emission standards currently applicable to boilers and
hydrochloric acid production furnaces. Finally, we prefer to use
compliance test data because the majority of the available data are
compliance test data.
Absent sufficient compliance test data for sources within the
source category to calculate floor levels, we default to explicitly
using data that are representative of the source's operating range
under conditions not designed to assess performance variability. Since
these so-called normal data do not typically reflect the upper range of
emissions from each source, we believe it is necessary to account for
emissions variability (in part) by expressing floors that are based on
normal data as long-term, annual average emission limits (since the
snap-shot data, by definition, do not reflect short-term variability).
We considered using all available emissions data to calculate the
floors, irrespective of whether they were normal or compliance test
data. We believe, however, that it is inappropriate to mix such
dissimilar data when calculating floor levels because it would bring
into question how to account for day-to-day emissions variability when
setting the format of the standard. For example, if a floor were
calculated using 50% percent normal data and 50% compliance data,
should the standard be expressed as a long-term limit or short-term
limit? This is critical because the averaging period associated with
the numerical emission limitation affects the stringency of the
standard. It is also unclear how mixing dissimilar data would affect
the statistical variability factor we apply to each floor to assure
that floor levels are achievable by the average of the best performing
sources. As discussed in Part Two, Section VI.E, we apply the
statistical variability factor to the floor levels to assure that the
average of the best performing sources would be able to replicate the
emission test results that were used to calculate the floor levels.
Mixing dissimilar data not only complicates the analyses, but also
could result in inconsistent evaluation of data (hence inconsistent
results), primarily because the ratio of normal data to compliance data
differs across HAP within each source and across all sources. We
therefore believe it is appropriate to assess ``like data'' explicitly
to assure results are consistent across HAP and source categories.
We prefer to use the most recent compliance test data to represent
each source in situations where we have data from multiple test
campaigns that were collected at different times. For example, we
typically have multiple test campaign emission information for cement
kilns and lightweight aggregate kilns because: (1) We conducted a
comprehensive data collection effort for these sources to update the
data base that was used to support the 1999 final rule; and (2) these
sources, prior to receiving their RCRA permit, are required to conduct
emissions tests every three years.
We believe it is appropriate to only use the most recent compliance
test data for a source because those data best reflect current
operations and emission levels. Older compliance test data may not be
representative of current emissions because: (1) Permitted feed and air
pollution control device operating levels may have been changed/
upgraded; (2) combustion unit and associated air pollution control
equipment design may have been changed/upgraded; and (3) standard
operating practices that relate to maintenance and upkeep may have been
changed/upgraded. As a result, we believe that a source's most recent
compliance data best reflect a source's upper range of emissions. We
considered using all of the sources historical compliance emissions
data to perhaps better account for day-to-day emissions variability. We
believe, however, that it is not appropriate to consider older
compliance emission test data to account for day-to-day emission
variability because: (1) The older compliance data may reflect varying
emissions merely because the source was previously operating with
poorer control levels, which is not an appropriate factor to consider
when assessing day-to-day emission variability; and (2) the most recent
compliance test data adequately accounts for day-to-day variability
because the operating levels demonstrated during the most recent
compliance test generally represent the maximum upper range of
operations and emissions.\62\
---------------------------------------------------------------------------

\62\ Operating parameter limits are established based on
compliance test operations to ensure emissions achieved during
normal operations do not exceed the emissions that were demonstrated
in the compliance test.
---------------------------------------------------------------------------

We do not apply the concept of using the most recent emissions test
information to normal emissions data (as previously discussed, we use
normal emission data to calculate floor levels only in situations where
we do not have sufficient compliance test data). We instead use all
normal emissions data that are available because we are concerned that
a source's most recent normal emissions may not be representative of
its average emissions. The most recent normal emissions data could
reflect emissions at the upper range of normal operations or the lower
end of normal operations. If we were to use only the most recent normal
emissions information, we may identify as best performers those sources
that were operating below their average levels. This would be
inappropriate because the floor level may be unachievable by the best
performing sources.
Finally, for liquid fuel-fired and solid fuel-fired boilers, we
eliminated emission test runs from the MACT analysis when we had
information that the source conducted sootblowing during that emission
test run. Boilers that burn fuels with high ash content are designed to
blow the soot off the tubes periodically to maintain proper heat
transfer. The soot can contain metal HAP, and emissions of these HAP
can increase during sootblowing. Although the current RCRA particulate
matter and metals emissions standards for these sources at Sec. Sec.
266.105 and 266.106 do not require sootblowing during compliance
testing, we have provided guidance recommending that sources blow soot
during one of the three runs of a compliance test condition and
calculate average emissions considering the frequency and duration of
sootblowing.\63\ We conclude that these sootblowing run data should not be

[[Page 21230]]

considered when establishing MACT floor, however, for several reasons.
We do not know if all sources that blow soot followed the guidance to
blow soot during a run of the test condition. If they did not, they
could be identified as a best performer but may not be able to achieve
the floor level when blowing soot. In addition, several boilers that
blew soot during a run of the test condition did not use our
recommended approach to calculate time-weighted average emissions
considering the frequency and duration of sootblowing. For these
sources, we cannot calculate time-weighted average emissions. We also
note that, for sources with emission control equipment, emissions
during sootblowing runs are not significantly higher than when not
blowing soot. This is because soot particles are relatively large and
easily controlled. For sources with no emission control equipment,
sootblowing increased particulate matter emissions for some sources,
but not others. In addition, we could not use the sootblowing run to
help address emissions variability by evaluating run variability
because the (in some cases) higher emissions during sootblowing are
unrelated to the factors affecting run variability that we are
evaluating (e.g., method precision and other largely uncontrollable
factors that affect run-to-run emissions during a test condition).
Finally, we note that the Agency did not propose to require sootblowing
to demonstrate compliance with the MACT standards for industrial,
commercial, and institutional boilers and process heaters.\64\ Although
for these reasons we conclude that it is appropriate not to consider
sootblowing run data to establish the MACT floor, we request comment on
alternative views.\65\
---------------------------------------------------------------------------

\63\ USEPA, ``Technical Implementation Document for EPA's Boiler
and Industrial Furnace Regulations'' EPA530-R-92-011, March 1992,
NTIS # PB92-154 947.
\64\ See 68 FR 1660 (January 13, 2003).
\65\ We note that a floor level considering sootblowing may be
higher than a floor level based on discounting sootblowing runs.
---------------------------------------------------------------------------

Because we do not consider sootblowing when establishing floor
levels, sootblowing would not be required during performance testing to
demonstrate compliance with the standards for particulate matter and
semivolatile and low volatile metals.\66\
---------------------------------------------------------------------------

\66\ The comparative risk assessment for this proposed rule did
not evaluate the impact of sootblowing on average emissions. To
ensure that RCRA permits are protective of human health and the
environment, regulatory officials may determine that the effect of
sootblowing on average emissions (i.e., considering the frequency
and duration of sootblowing) should be considered in some
situations, such as a source with uncontrolled or poorly controlled
particulate emissions and with relatively high particulate matter or
toxic metal emissions.
---------------------------------------------------------------------------

C. How Did We Evaluate Whether It Is Appropriate To Issue Separate
Emissions Standards for Various Subcategories?

The third step we use to calculate MACT floor levels evaluates
subcategorization options. CAA section 112(d)(1) allows us to
distinguish among classes, types, and sizes of sources within a
category when establishing floor levels. Subcategorization typically
reflects ``differences in manufacturing process, emission
characteristics, or technical feasibility.'' See 67 FR 78058.
We use both engineering principles and a statistical analysis to
assess whether it is appropriate to subcategorize and issue separate
emission standards. We first use engineering principles to determine
potential subcategory options. These subcategory options are discussed
in more detail in Part Two Section II for each source category. As
discussed in greater detail below, we then determine if there is a
statistical difference in the emission characteristics between these
potential subcategory options. Finally, we conduct a technical analysis
to determine if the statistical analysis results are consistent with
sound engineering judgement.
``Analysis of Variance'' (ANOVA) is the statistical test used to
cross-check these engineering judgements. ANOVA, a conventional
statistical method, evaluates whether there are differences in the mean
of HAP emissions levels from two or more different potential
subcategories (i.e., do the different subcategories of HAP data come
from distinctly different populations). Subcategories are considered
significantly different using a 95% confidence level. ANOVA is used in
combination with engineering principles to sequentially identify
significant differences between various different combinations of
potential subcategories. See U.S. EPA ``Draft Technical Support
Document for HWC MACT Replacement Standards, Volume III: Selection of
MACT Standards,'' March 2004, Chapter 4, for detailed steps and results
of the ANOVA evaluation process.

D. How Did We Rank Each Source's Performance Levels To Identify the
Best Performing Sources for the Three MACT Methodologies?

The fourth step used in determining the MACT floor levels involves
ranking each source's performance level to identify the best
performers. Below we discuss the general ranking procedure used for
each of the three MACT methodologies and the statistical methodology
used to perform the ranking process.
1. Emissions-Based Methodology Ranking Procedure
As previously discussed in Part Two, Section VI.A, the emissions-
based approach defines best performers as those sources with the lowest
emissions in our database. Each source's emission test runs are first
converted to an upper 99% confidence level in order to rank performance
not only on the average emission levels each source achieves, but also
on the emissions variability each source demonstrates during the
emissions tests. We believe this is appropriate because a source's
ability to consistently control its emissions below the MACT floor
levels is important in determining whether a source is in fact a well
designed and operated source.\67\ We then array and rank each source by
its 99% upper confidence emission levels from best to worst (i.e.,
lowest to highest). For existing source floors, we identify the best
performers as either sources at the 12th percentile ranking and below
or the lowest 5 ranked sources values if we have data from less than 30
sources. The best performing source for the new source floor is simply
the source with the single lowest ranked 99% upper confidence emission
level.
---------------------------------------------------------------------------

\67\ For example, a source with average emissions of 100 and
calculated variability of 10 would be ranked as a better performing
source when compared to a source with average emissions of 100 and a
calculated variability of 20.
---------------------------------------------------------------------------

2. SRE/Feed Ranking Procedure
As previously discussed, the SRE/Feed methodology approach defines
best performers as those sources with the best combined front-end
hazardous waste feed control and back-end air pollution control
efficiency as defined by our ranking procedure. The first step involves
ranking each source's feed control level. As with the emissions-based
approach, we first convert each source's feed control run levels (i.e.,
hazardous waste maximum theoretical emission concentration level or
thermal feed concentrations) to an upper 99% confidence level. We then
array each source's 99% upper confidence feed control levels from best
to worst (i.e., lowest to highest). Next we assign a feed control
ranking score to each source. The source with the lowest feed control
value gets a ranking of 1, and the source with highest feed control
value receives the highest numerical ranking.
The second step ranks each source's system removal efficiency,
which is a measure of the percent of metal or

[[Page 21231]]

chlorine that is emitted as compared to the amount fed to the
combustion unit. Again, we first convert each source's system removal
efficiency run values to an upper 99% confidence level value. We then
array each source's 99% upper confidence levels from best to worst
(i.e., highest to lowest). Next we assign a system removal efficiency
ranking score to each source. The source with the best system removal
efficiency gets a ranking of 1, and the source with the worst system
removal efficiency receives the highest numerical ranking.
As with the emissions ranking procedure discussed above, our feed
control and system removal efficiency ranking procedure measures
performance not only on the average feed control and system removal
efficiency level each source achieves, but also on the feed and system
removal efficiency variability each source demonstrates during the
emissions tests. This is appropriate because a source's ability to
consistently regulate its control mechanisms to achieve MACT emissions
is important in determining whether a source is in fact a well designed
and operated source.
Third, we add each source's feed control ranking score and system
removal efficiency ranking score together in order to calculate an
aggregated SRE/Feed score. We then array and rank each source's
aggregated score from best to worst (i.e., lowest to highest). For
existing source floors, we identify the best performers as sources at
the 12th percentile aggregate ranking and below or sources with the
lowest 5 aggregated scores if we have data from less than 30 sources.
The best performing source for the new source floor is simply the
source with the single lowest aggregated score.
3. Technology Approach Ranking Procedure for the Particulate Matter Standard
As previously discussed in Part Two, Section VI.A.2.a, the best
performing sources for the particulate matter proposed floor levels are
determined from a pool of sources that use the MACT-defining back-end
control technology. We assess only the emissions from those sources
equipped with the MACT-defining control technology (or technologies),
and, as with the previously discussed methodologies, we convert each
source's emission run values to an upper 99% confidence level value.
Emissions information from each source is then grouped based on the
type of MACT control each source uses. The first group contains
emissions information from sources equipped with the best ranked MACT
control device; the second group includes emissions information from
sources equipped with the second best ranked MACT control technology
(if there is more than MACT control technology), and so on.
We then array and rank each source's 99% upper confidence emission
levels from best to worst (i.e., lowest to highest) within each of
these groups. If there is only one defined MACT control technology, the
best performing sources are those sources with the lowest 99% upper
confidence emission levels amongst the sources using this MACT control
technology. The lowest emitting sources are added to a list of best
performers up until the number of sources that are included in this
list is representative of 12 percent of sources within the source
category (for the existing source floor determination). If there is
more than one defined MACT control technology, the list of best
performers first considers sources with the lowest 99% upper confidence
emission levels that are equipped with the best ranked control device
up until the number of sources that are included in this list is
representative of 12 percent of sources within the sources category. If
additional sources need to be added to this list to appropriately
represent 12% of the sources within the source category, then sources
with the lowest emissions that are equipped with the second best MACT
control device are added until the appropriate number of best
performing sources are obtained.\68\ For the new source floor, the best
performer is simply the single source equipped with the best ranked
MACT control device with the lowest 99% upper confidence emission level.
---------------------------------------------------------------------------

\68\ Note that this methodolgy does not base the floor on the
highest emitting source amongst these best performers (as did the
``expanded MACT pool'' did for 1999 rule). Rather, the floor is
determined by calculating the average performance of all best
performing sources.
---------------------------------------------------------------------------

4. Technology Approach Ranking Procedure for the Total Chlorine Floor
for Hydrochloric Acid Production Furnaces
As previously discussed in Part Two, Section VI.A.2.b, the
technology approach used to determine the total chlorine floor levels
for hydrochloric acid production furnaces defines best performers as
those sources with the best total chlorine system removal efficiency.
The ranking procedure used for this methodology is identical to that
used in the emissions-based approach with the exception that system
removal efficiencies are ranked instead of emissions. Each source's
total chlorine system removal efficiency run values are first converted
to an upper 99% confidence level. We then array and rank each source's
99% upper confidence system removal efficiencies from best to worst
(i.e., highest to lowest). For existing source floors, we define best
performers as either: (1) Sources at the 12th percentile ranking and
below; or (2) sources with the lowest 5 rankings if we have data from
less than 30 sources. The best performing source for the new source
floor is simply the source with the single highest 99% upper confidence
system removal efficiency.
5. Description of the Statistical Procedures Used To Identify the 99%
Confidence Levels
As previously discussed, each source's performance level is first
converted to an upper 99% confidence level in order to rank performance
not only on the average performance level each source achieves, but
also on the emissions variability each source demonstrates during the
emissions tests. We believe this is appropriate because a source's
ability to consistently control its emissions below the MACT floor
levels is important in determining whether a source is in fact a well
designed and operated source.
Sources are ranked based on their projected ``upper 99% confidence
limit'' (or lower 99% confidence limit for system removal efficiency).
For emissions and feedrates, upper 99% confidence limits are determined
using a ``prediction limit'' calculation procedure. The prediction
limit is an estimate of the level which will capture 99 out of 100
future test condition averages (where each average comprise three
individual test runs). HAP emissions data within each source are
determined to be normally distributed. The prediction limit is
calculated for each source based on the average, standard deviation,
and number of individual test runs.
For system removal efficiencies, the lower 99% confidence limit is
determined using the ``two parameter Beta distribution''. The beta
distribution is used for modeling proportions, i.e., system removal
efficiencies, is highly robust, and appropriately bounded by zero and
1. Beta distribution modeling parameters are determined based on the
``method of moments'' using the average and standard deviation of the
individual source data. The lower 99% estimate comes directly from the
Beta distribution model. See USEPA ``Draft Technical Support Document
for HWC MACT Replacement Standards, Volume III: Selection of MACT Standards,''

[[Page 21232]]

March 2004, Chapter 8, for further discussion.

E. How Did EPA Calculate Floor Levels That Are Achievable for the
Average of the Best Performing Sources?

The emissions data we used to establish MACT floor were obtained by
manual sampling of stack gas. To ensure that the average of the best
performing sources can routinely achieve the floor during future
performance testing under the MACT standards, we must account for
emissions variability.
We account for long-term emissions variability by: (1) Using
compliance test emissions data, when available, to establish floors;
(2) when other than compliance test data must be used to establish the
floor, basing compliance on an annual average. In addition, we add a
statistically-derived variability factor to the floor to account for
run-to-run variability. This variability factor ensures that the
average of the best performing sources can achieve the floor level in
99 of 100 future tests if the best performing sources replicate the
operating conditions and other factors that affect the emissions we use
to represent the performance of those sources.
1. How Does Using Compliance Test Data Account for Variability?
We use RCRA compliance test emissions data, when available, to
establish the floors because compliance test data largely account for
emissions variability. Under RCRA compliance testing, sources must
establish operating limits based on operating conditions demonstrated
during the test. Each source designs the compliance test such that the
operating limits it establishes account for the variability of
operating parameter levels it expects to encounter during its normal
operations (e.g., feedrate of metals and chlorine; air pollution
control device operating parameters, production rate). Thus, operating
conditions during these tests generally reflect the upper range of
emissions from these sources. Using a source's compliance test
emissions to establish the floor accounts largely for long-term
emissions variability. However, this does not necessarily account for
factors that affect variability. As previously discussed, our snap-shot
data base emissions information does not necessarily account for
inherent variability such as feedrate fluctuation over time due to
production process changes, uncertainties associated with correlations
between operating parameter levels and emissions, precision and
accuracy differences that may result from using different stack
sampling crews and analytical laboratories, and changes in emission of
materials (SO2 being an example) that may cause test method
interferences.
Use of compliance test data also does not account for run-to-run
variability. We thus use a statistically-derived variability factor to
account for the variability in emissions that would result if the best
performing sources were to replicate their compliance tests, as
discussed below.\69\
---------------------------------------------------------------------------

\69\ EPA did not statistically assess run-to-run variability in
the 1999 rule (although we noted that it existed; see 64 FR at
52857. The reason is that by using the expanded MACT pool approach
to account for variability (using surrogate sources from outside the
best performing to assess the best performing sources' variability)
we felt we had accounted for all such run-to-run variability. Id.
Since we are not proposing to expand the MACT pool here, it is
necessary to account for run-to-run variability by some other means.
---------------------------------------------------------------------------

In addition, use of compliance test data may not account for long-
term variability of particulate matter emissions from sources equipped
with a fabric filter. Accordingly, we also use a statistically-derived
variability factor to account for this variability, as discussed below.
2. How Does Using Long-Term Averaging Account for Emissions Variability
When Using Other Than Compliance Test Data?
RCRA compliance test emissions data are not available for some
metals (mercury in particular) for some source categories. In these
cases, we use other emissions test data to establish the floor. These
other test data are snap shots of emissions within the range of normal
emissions. To largely account for emissions variability when using
emissions data assumed to represent the average of normal emissions, we
propose to express the floor as a long-term, yearly, average. Sources
would comply with the floor by establishing limits on metal feedrate
and air pollution control device operating parameters. Compliance with
the metal feedrate limits would be based on an annual average feedrate,
while compliance with the air pollution control device operating limits
would be based on short-term limits (e.g., hourly rolling average). We
propose short-term averages for air pollution control device operating
parameters because the parameters may not correlate with emissions
linearly; emissions resulting when an air pollution control device
parameter is above the limit thus may not be offset by emissions
resulting when the air pollution control device parameter is below the
limit. See 1999 rule, 64 FR at 52920.
As discussed above, we also use a statistically derived variability
factor to account for the variability in emissions that would result if
the best performing sources were to replicate the emissions tests we
use to establish the floor, as discussed below.
We use the normal emissions data to represent the average emissions
from a source even though we do not know where the emissions may fall
within the range of normal emissions; the emissions may be at the high
end, low end, or close to the average emissions. It may be reasonable
to assume the emissions represent average emissions, given that we have
emissions data from several sources, and that emissions for these
sources in the aggregate could be expected to fall anywhere within the
range of normal emissions. Note that, as previously discussed, we have
not applied the concept of using the most recent emissions test
information to normal emissions data because we are concerned a
source's most recent normal emissions may not be representative of a
source's true average emissions. These emissions could reflect
emissions at the upper range of normal operations, or instead, could
reflect emissions at the lower end of normal operations. If we were to
use only the most recent normal emissions information, the MACT
standard setting process may identify best performers as those sources
that operate below their normal levels. This may be inappropriate
because the floor level may be unachievable even by the best performing
sources. We invite comment as to whether floors that are based on
normal data are in fact achievable by the best performing sources, and
whether there is perhaps a more appropriate method to identify floors
that are based on normal data.
3. What Statistical Procedures Did EPA Use To Calculate Floor Levels?
In order to calculate a floor that would be achievable by the
average of the best performing sources, we considered the variability
in emissions across runs of the test conditions of the best performing
sources. We also use statistical procedures to account for long-term
variability in particulate matter emissions for sources equipped with
fabric filters. We discuss these procedures and the rationale for using
them below.
a. Run-to-Run Variability. The MACT floor level is determined by
modeling a normally distributed population that has an average and
variability that are equal to that of the ``average'' of the best
performing MACT pool sources. The MACT floor is calculated using a

[[Page 21233]]

modified prediction limit procedure. The prediction limit is designed
to capture 99 out of 100 future three-run averages from the ``average''
of the best performing MACT sources.
Specifically, the modified prediction limit for calculating the
MACT floor is the sum of the average of the best performing sources and
the ``pooled'' variability of the best performing sources. The pooled
variability term accounts for the expected variability in future
measurements due to variations resulting from system operation and
measurement activities. The pooled variability term is based in part on
the observed variance of individual runs within test conditions from
the best performing MACT pool sources. The pooled variability term
assumes that variability from the individual best performing sources
are independent (not related), and thus are additive (and not
averaged). The pooled variability term is a function of the variances
of the individual MACT pool sources, the number of MACT pool sources,
the desired 99% confidence level, and the number of future test runs
for demonstrating compliance (assumed to be 3). See USEPA ``Draft
Technical Support Document for HWC MACT Replacement Standards, Volume
III: Selection of MACT Standards,'' March 2004, Chapter 7, for
discussion of the detailed steps and prediction limit formula used to
calculate the MACT floors.
b. Particulate Matter Variability for Fabric Filters. Compliance
test emissions of particulate matter from sources that are equipped
with a fabric filter may not account for long-term variability because
it is difficult to maximize emissions during the compliance test.\70\
Fabric filters control particulate matter emissions generally to the
same concentration irrespective of the particulate matter loading at
the inlet to the fabric filter. Because there are no operating
parameters that can be readily changed to increase emissions, it is
difficult to maximize emissions of particulate matter from a fabric
filter during compliance testing.\71\
---------------------------------------------------------------------------

\70\ We note that semivolatile and low volatile metal emissions,
however, can be maximized during compliance testing for sources
equipped with a fabric filter. Metals may be spiked in the hazardous
waste feed to levels that account for long-term feedrate
variability. Although the particulate matter emission concentration
would not be expected to increase during a metals compliance test
for a source equipped with a fabric filter, the semivolatile and low
volatile metals emissions concentrations would increase. This is
because the concentration of metals in the emitted particulate
matter would increase.
\71\ We note that this situation is unique for fabric filters.
Sources equipped with other control devices--electrostatic
precipitators, ionizing wet scrubbers, and wet scrubbers--can
readily change the device's operating conditions (e.g., power input
to an electrostatic precipitator; pressure drop across a wet
scrubber) during compliance testing to ``detune'' collection
efficiency and increase emissions. In addition, these other control
devices provide ``percent reduction'' control of pollutants whereby
as inlet loading increases, emission concentrations also increase.
Thus, increasing the inlet loading (e.g., by spiking the ash
feedrate to an incinerator) even without detuning the control device
would also increase emissions of particulate matter for devices
other than a fabric filter.
---------------------------------------------------------------------------

To address long-term variability in particulate matter emissions
for fabric filters we developed a universal variability factor (UVF).
The UVF represents the standard deviation of the pooled runs from
multiple compliance tests for a source, and is imputed as a function of
the source's emission concentration. We use the UVF to account for both
long-term and run-to-run variability to calculate the floor using the
procedures discussed above in lieu of the pooled variability term for
the most-recent test condition run variability.
To develop the data base to calculate the UVF, we considered each
best performing source that is equipped with a fabric filter and for
which we have two or more compliance tests for particulate matter. We
considered all compliance test particulate matter emissions data for
these sources, including those test conditions we previously labeled as
``IB'' (representing in-between), indicating that emissions levels are
lower than for another test condition of the compliance test campaign.
We include historical test campaign data where available for
incinerators, cement kilns, and lightweight aggregate kilns.
Considering historical compliance test data and compliance test data
labeled IB is appropriate because any differences in emission levels
(over time or among compliance test results for a test campaign) should
be indicative of emissions variability given that fabric filters
generally produce constant emission concentrations and are difficult to
detune to increase emissions for compliance testing. Finally, we
combined test conditions for multiple on-site sources where both the
combustor and fabric filter have similar design and operating
characteristics. Combining the test conditions for such sources as if
they represent emissions from a single source better accounts for
emissions variability.
To calculate the UVF, we calculated the pooled standard deviation
of the runs for each source for which we have data for two or more
compliance tests and plotted this standard deviation versus particulate
matter emission concentration for all such sources. It is reasonable to
aggregate the data for sources across all source categories given that
there is no reason to believe that the standard deviation/emissions
relationship would vary from source category to source category. We
then identified the best-fit curve for the data. The best fit curve is
a power function that achieved a R² of 0.83, indicating a
good power function correlation between standard deviation and emission
concentration.\72\
---------------------------------------------------------------------------

\72\ The procedure we use to identify the universal variability
factor for particulate matter emissions for sources equipped with
fabric filters is discussed in detail in USEPA, ``Draft Technical
Support Document for HWC MACT Replacement Standards, Volume III:
Selection of MACT Standards,'' March 2004, Chapter 5.3. Please note
that we consider alternative approaches to identify the universal
variability factor as discussed in the technical support document,
and request comment on those alternatives.
---------------------------------------------------------------------------

We use the best-fit curve to impute a standard deviation for each
best performing source (that is equipped with a fabric filter) as a
function of the source's particulate matter emissions. We use the
source's average compliance test emissions (i.e., including historical
compliance test emissions that we label in the data base as ``WC'' and
``IB'') to represent average emissions.

F. Why Did EPA Default to the Interim Standards When Establishing Floors?

When we calculate floor levels for several standards for the Phase
I sources, the floor levels would be higher than the currently
applicable interim standards at Sec. Sec. 63.1203, 63.1204, and
63.1205. As explained earlier, we conclude that today's proposed floor
levels can be no higher than the interim standards because all sources,
not just the best performing sources, are achieving the interim
standards. The most recent emissions data in our data base are from
compliance testing in 2001 and do not represent emissions tests from
sources used to demonstrate compliance with the interim standards, thus
the data we used to calculate the proposed floor levels generally does
not reflect the control upgrades necessary for compliance with the
interim standards. The fact that we are ``capping'' the floor at the
interim standard level does not mean our proposed methodology is less
conservative than the methodology used in the 1999 rule. Our calculated
floor levels can be higher than the interim standards for several
reasons. As a result of our data collection effort, we have compiled
more emissions information from some source categories that result in
higher calculated floor levels (e.g., dioxin/furans for lightweight aggregate

[[Page 21234]]

kilns). Some of the instances where we ``capped'' the floor at the
interim standard level occurred when the interim standard was a beyond-
the-floor standard promulgated in 1999 (e.g., semivolatile metals for
lightweight aggregate kilns). Finally, some standards are ``capped''
because we used different types of data to calculate the proposed
floors (e.g., the 1999 rule generally considered normal mercury data to
establish the mercury floor for incinerators, whereas today's proposed
approach used compliance test data to calculate the mercury floor).

G. What Other Options Did EPA Consider?

We considered five other alternative approaches to establish the
full suite of floor levels for each source category. The first two
alternative options use different combinations of the three main
methodology options to determine the proposed floors. Note that we also
conducted a complete economics and benefits analysis for these first
two alternative options. See USEPA ``Draft Technical Support Document
for HWC MACT Replacement Standards, Volume V: Emission Estimates and
Engineering Costs,'' March, 2004 for more information. The third option
identifies best performing sources by considering emissions of metals
and particulate matter simultaneously, instead of pollutant by
pollutant. The fourth option is an approach recommended by the
Environmental Treatment Council. Finally, the fifth option identifies
best performing sources as those sources with the best back-end control
efficiencies, as measured by their associated system removal
efficiencies. After review of comments we may use one or more of these
approaches in toto or part to establish final standards. We explain
below how these approaches work and the rationale for considering them.
1. What Is Alternative Option 1, and What Is the Rationale?
Under alternative option 1, we do not use the SRE/Feed methodology
to calculate any floors. We use the emissions-based approach to
establish all the floors, other than the exceptions that are explained
below. We express emission standards for energy recovery units in units
of hazardous waste thermal emissions when appropriate. All other
emission standards under this approach are expressed as stack gas
emission concentrations. The two exceptions under this option uses the
technology-based approach for the particulate matter standard (for all
source categories) and the total chlorine standard for hydrochloric
acid production furnaces, as was done for today's proposed standards.
We evaluated this option because it is simpler and more
straightforward to use than the SRE/Feed Approach. The best performing
sources simply are those with the lowest emissions in our data base,
irrespective of the level of feed control or back-end control a source
achieves. The advantages of using the air pollution control technology
approach and expressing emission standards using the hazardous waste
thermal emissions format for energy recovery units are retained.
Although we have doubts that standards based on these limits are
achievable even by the best performing sources (as noted earlier) and
that this approach could be based on unrepresentatively low hazardous
waste feedrates, we invite comment as to whether this approach is
appropriate. We present the results of using alternative option 1 to
identify floor levels for existing sources in Table 3 below. See U.S.
EPA ``Draft Technical Support Document for HWC MACT Replacement
Standards, Volume III: Selection of MACT Standards,'' March 2004,
Chapters 16, 17, and 18 for documentation of the floor levels.

Table 3.--Floor Levels for Existing Sources Under Alternative Option 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hydrochloric acid
Incinerators Cement kilns Lightweight Solid fuel-fired Liquid fuel-fired production
aggregate kilns boilers \1\ boilers \1\ furnaces \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans (ng TEQ/dscm)..... 0.28 for dry APCD 0.20 or 0.40 + 0.20 or 400[deg]F CO or THC standard 3.0 or 400[deg]F CO or THC standard
and WHB 400[deg]F at APCD at kiln as a surrogate. at APCD inlet for as a surrogate.
sources,\6\ 0.20 inlet.\7\ outlet.\7\ dry APCD sources;
or 0.40 + CO or THC
400[deg]F at APCD standard as
inlet for surrogate for
others.\7\ others.
Mercury......................... 130 [mu]g/dscm \7\ 31 [mu]g/dscm \2\. 19 [mu]g/dscm \2\. 10 [mu]g/dscm..... 3.7E-6 lb/MMBtu 2, Total chlorine
5. standard as
surrogate.
Particulate Matter.............. 0.015 gr/dscf \7\. 0.028 gr/dscf..... 0.025 gr/dscf \7\. 0.063 gr/dscf..... 0.032 gr/dscf..... Total chlorine
standard as
surrogate.
Semivolatile Metals (lead 19 [mu]g/dscm..... 1.3E-4 lb/MMBtu 3.1E-4 lb/MMBtu 170 [mu]g/dscm.... 1.1E-5 lb/MMBtu 2, Total chlorine
+cadmium). \5\. \5\ and 250 [mu]g/ 5. standards as
dscm.\3\ surrogate.
Low Volatile Metals (arsenic + 14 [mu]g/dscm..... 1.1E-5 lbs/MMBtu 9.5E-5 lb/MMBtu 210 [mu]g/dscm.... 7.7E-5 lb/MMBtu 4, Total chlorine
beryllium + chromium). \5\. \5\ and 100 [mu]g/ 5. standard as
dscm.\3\ surrogate.
Total Chlorine (hydrogen 0.93 ppmv......... 41 ppmv........... 600 ppmv \7\...... 440 ppmv.......... 5.7E-3 lb/MMBtu 14 ppmv or
chloride + chlorine gas). \5\. 99.9927% system
removal
efficiency.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards apply to major sources only for solid fuel-fired boilers,
liquid fuel-fired boilers, and hydrochloric acid production furnaces.
\2\ Standard is based on normal emissions data.
\3\ Sources must comply with both the thermal emissions and emission concentration standards.
\4\ Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal
total for liquid fuel-fired boilers.
\5\ Standards are expressed as mass of pollutant contributed by hazardous waste per million Btu contributed by the hazardous waste.
\6\ APCD denotes ``air pollution control device,'' WHB denotes ``waste heat boiler.''

[[Page 21235]]

\7\ Floor level represents the ``capped interim standard level,'' which means the floor level determined by the associated methodology was less
stringent than the interim standard level.

2. What Is Alternative Option 2, and What Is the Rationale?
Under alternative option 2, we use the emissions-based approach to
establish all floors and there are no exceptions. All floor levels are
expressed in units of stack gas concentrations (we do not express any
floors for energy recovery units in terms of thermal emissions). The
best performing sources for all floors are those with the lowest
emissions, on a stack gas concentration basis.
We are not proposing this alternative option because it has the
disadvantages that the more complicated provisions of Option 1 (and to
some extent Option 2) address: (1) By not using the SRE/Feed Approach
for metals and total chlorine, it does not ensure that sources could
use either feedrate control or back-end control to achieve the floor;
(2) the approach may be inappropriately biased against sources that
burn hazardous waste fuel at high firing rates because it does not
express the standards in units of hazardous waste thermal emissions;
(3) it inappropriately considers feed control for particulate matter
and for hydrochloric acid production furnaces by not using the Air
Pollution Control Device Approach for those floors; and (4) it may not
appropriately estimate the performance of the average of the 12 percent
best performing sources given that those best performers may have low
emissions in part because their raw material and/or fossil fuels
contained low levels of HAP during the emissions test (and because we
do not believe feed control of HAP in raw material and fossil fuel
should be assessed as a MACT floor control because it could result in
floor levels that are not replicable by the best performing sources,
nor duplicable by other sources).
We invite comment as to whether this alternative approach is
appropriate, noting the doubts we have voiced above. We present the
results of using this alternative option 2 to identify floor levels for
existing sources in Table 4 below. See USEPA ``Draft Technical Support
Document for HWC MACT Replacement Standards, Volume III: Selection of
MACT Standards,'' March 2004, Chapter 16, for more information.

Table 4.--Floor Levels for Existing Sources Under Alternative Option 2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hydrochloric acid
Incinerators Cement kilns Lightweight Solid fuel-fired Liquid fuel-fired production
aggregate kilns boilers 1 boilers 1 furnaces 1
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dioxin/Furans (ng TEQ/dscm)..... 0.28 for dry APCD 0.20 or 0.40 + 0.20 or 400[deg]F CO or THC standard 3.0 or 400[deg]F CO or THC standard
and WHB sources; 400[deg]F at APCD at kiln as a surrogate. at APCD inlet for as a surrogate.
5 0.20 or 0.40 + inlet.6 outlet.\6\ dry APCD sources;
400[deg]F at APCD CO or THC
inlet for standard as
others.6 surrogate for
others.
Mercury......................... 130 [mu]g/dscm 6.. 31 [mu]g/dscm 2... 19 [mu]g/dscm 2... 10 [mu]g/dscm..... 0.47 [mu]g/dscm 2. Total chlorine
standard as
surrogate.
Particulate Matter.............. 0.0040 gr/dscf.... 0.016 gr/dscf..... 0.025 gr/dscf 6... 0.065 gr/dscf..... 0.0028 gr/dscf.... Total chlorine
standard as
surrogate.
Semivolatile Metals (lead + 19 [mu]g/dscm..... 68 [mu]g/dscm..... 130 [mu]g/dscm.... 170 [mu]g/dscm.... 8.7 [mu]g/dscm 2.. Total chlorine
cadmium). standard as
surrogate.
Low Volatile Metals (arsenic + 14 [mu]g/dscm..... 8.9 [mu]g/dscm.... 82 [mu]g/dscm..... 210 [mu]g/dscm.... 28 [mu]g/dscm 4... Total chlorine
beryllium + chromium). standards as
surrogate.
Total Chlorine (hydrogen 0.93 ppmv......... 41 ppmv........... 600 ppmv 6........ 440 ppmv.......... 2.4 ppmv.......... 2.0 ppmv.
chloride + chlorine gas).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
1 Particulate matter, semivolatile metal, low volatile metal, and total chlorine standards apply to major sources only for solid fuel-fired boilers,
liquid fuel-fired boilers, and hydrochloric acid production furnaces.
2 Standard is based on normal emissions data.
3 Sources must comply with both the thermal emissions and emission concentration standards.
4 Low volatile metal standard for liquid fuel-fired boilers is for chromium only. Arsenic and beryllium are not included in the low volatile metal total
for liquid fuel-fired boilers.
5 APCD denotes ``air pollution control device'', WHB denotes ``waste heat boiler'.
6 Floor level represents the ``capped interim standard level'', which means the floor level determined by the associated methodology was less stringent
than the interim standard level.

3. What Is Alternative Option 3, and What Is the Rationale?
Under alternative option 3, we evaluated an approach to identify
the best performing sources for particulate matter, semivolatile
metals, and low volatile metals that considers how well a source is
controlling these pollutants simultaneously. Simultaneous control of
these pollutants is an appropriate consideration because these
pollutants are controlled by the same emission control device, the
particulate matter control device (e.g., a wet scrubber, electrostatic
precipitator, or fabric filter). We call this alternative approach the
Simultaneous Achievability for Particulates (SAP) Approach. See USEPA,
``Draft Technical Support Document for HWC MACT Replacement Standards,
Volume III: Selection of MACT Standards,'' March 2004, Chapters 10 and 19.

[[Page 21236]]

We evaluated semivolatile metal and low volatile metal emissions
for energy recovery sources--cement kilns, lightweight aggregate kilns,
and liquid fuel-fired boiler--under two emissions-based SAP
alternatives: hazardous waste thermal emissions, and stack gas
concentrations. The hazardous waste thermal emissions option assesses
semivolatile metal and low volatile metal thermal emissions for energy
recovery units, while assessing particulate matter using the emissions-
based stack gas concentration approach. The emissions-based stack-gas
concentration approach assesses stack gas concentrations (as opposed to
thermal emissions) for all HAP. Note that we did not evaluate
hydrochloric acid production furnaces under this SAP approach because
we propose to use the total chlorine standard as a surrogate to control
emissions of particulate matter and metals for these sources.
Under the SAP approach, we rank emissions for each pollutant across
the sources for which we have emissions data for that pollutant. For
ranking, we use the upper 99% confidence interval for the average of
the runs of the test condition for a source. For example, if we have
semivolatile metal emissions data for 15 sources, the lowest
semivolatile metal emissions level is ranked one and the highest is
ranked 15. To identify the best performing sources for all three
pollutants simultaneously, we calculate an aggregate rank score for
each source. For example, if source A has a rank of 5 for particulate
matter, a rank of 10 for semivolatile metals, a rank of 15 for low
volatile metals, the aggregate rank score for that source is 10, the
average rank across the pollutants. If we do not have emissions data
for a pollutant for a source, there is no rank score for that
pollutant, and that pollutant is not considered in the aggregate rank
score for the source.
To identify the best performing sources in the aggregate, we rank
the aggregate rank scores for the sources from lowest to highest. If we
have emissions data for all three pollutants for all sources, the 5 (or
12% if we have data for more than 30 sources) sources with the lowest
aggregate rank scores are the best performing sources. If we have
incomplete data sets for some sources for a source category, the best
performing sources for a pollutant (i.e., particulate matter,
semivolatile metals, or low volatile metals) are the sources with the
lowest aggregate rank scores and for which we have emissions data.
We present the alternative MACT floors for existing sources under
the SAP approach in Table 5 below.

Table 5.--Floor Levels for Existing Sources Under the SAP Approach
----------------------------------------------------------------------------------------------------------------
Particulate
Source category Emissions-based matter floor Semivolatile metals Low volatile metals
approach (gr/dscf) floor floor
----------------------------------------------------------------------------------------------------------------
Incinerators..................... Stack Gas Conc...... 0.0040 53 [mu]g/dscm....... 50 [mu]g/dscm.
Cement Kilns..................... Thermal Emissions... 0.027 190 lb/trillion Btu. 20 lb/trillion Btu.
Stack Gas Con....... 0.015 103 [mu]g/dscm...... 14 [mu]g/dscm.
Lightweight Aggregate Kilns...... Thermal Emissions... 0.019 300 lb/trillion Btu. 95 lb/trillion Btu.
Stack Gas Conc...... 0.019 120 [mu]g/dscm...... 89 [mu]g/dscm.
Solid Fuel-Fired Boilers......... Stack Gas Conc...... 0.090 180 [mu]g/dscm...... 230 [mu]g/dscm.
Liquid Fuel-Fired Boilers........ Thermal Emissions... 0.0039 81 lb/trillion Btu.. 180 lb/trillion
Btu.
Stack Gas Conc...... 0.0039 26 [mu]g/dscm....... 210 [mu]g/dscm.
----------------------------------------------------------------------------------------------------------------

We request comment on this alternative approach for identifying
MACT floors. If we use this approach in the final rule to identify MACT
floors, we would promulgate a beyond-the-floor standard for particulate
matter of 0.030 gr/dscf for existing solid fuel-fired boilers for the
same reasons we are proposing today a beyond-the-floor standard. See
Part Two, Section X.C for a discussion of today's proposed beyond-the-
floor particulate matter standard for solid fuel-fired boilers.
See USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,'' March
2004, Chapters 10 and 19, for a more detailed explanation of this SAP
analysis.
4. What Is Alternative Option 4, and What Is the Rationale?
The Environmental Technology Council (ETC) recommends an approach
to calculate floor levels for metals and chlorine that uses a low
feedrate screen and addresses emissions variability differently than
the options we evaluated.\73\ We may use this approach in total or in
part to support a final rule, and therefore request comment on the
approach.
---------------------------------------------------------------------------

\73\ Update on MACT Floor Evaluations Revised Data Base,
Environmental Technology Council, February 2003.
---------------------------------------------------------------------------

Under ETC's approach, test conditions are screened from further
consideration if metals or chlorine were not fed at levels that
challenge the emissions control system.\74\ Feedrates of metals and
chlorine in hazardous waste are normalized to account for size of the
combustor by converting feedrates to maximum theoretical emissions
concentrations. A low maximum theoretical emissions concentration
filter is used to screen out emissions from low feed test conditions,
where the filter is the lower 99% confidence limit of the mean of the
maximum theoretical emissions concentrations for all test conditions
for all sources within a source category.
---------------------------------------------------------------------------

\74\ This approach therefore identifies a de minimis feed
control level for each source category and does not evaluate
emissions from these de minimus feeders in the MACT analysis because
these de minimis feed control levels may not be feasible for other
sources to duplicate. The screen is performed individually by
pollutant so that if semivolatile metals were fed at rates that
challenged the emissions control system but low volatile metals were
not, only the low volatile metal emissions data for that test
condition would be screened from further analysis.
---------------------------------------------------------------------------

ETC's approach also excludes specialty units, defined as sources
that burn munitions and radiological waste (i.e., Department of Defense
and Department of Energy sources). ETC believes that these sources burn
wastes with atypical concentrations of ash and metals that may
inappropriately skew the calculation of floor levels. Under this
approach, we would either subcategorize and issue separate emission
standards for these specialty units, or omit these speciality units
from the MACT analysis and require the specialty units to comply with
the floor levels that are determined from emissions of the non-
specialty units.
After applying the low maximum theoretical emissions concentration
filter and excluding specialty units, this approach identifies the best
performing sources by ranking emissions from

[[Page 21237]]

lowest to highest.\75\ Run variability is not considered at this point.
For incinerators, cement kilns, and lightweight aggregate kilns where
we may have historical compliance test emissions from several test
campaigns for a source, test conditions from the campaign with the
lowest compliance test emissions are used to identify the best
performers.
---------------------------------------------------------------------------

\75\ This low feed screen is not applied to cement kilns and
lightweight aggregate kilns for the particulate matter standard
because ash feedrate is not considered to be a dominant factor that
influences particulate matter emissions (rather, particulate matter
emissions are more a function of the back-end control device efficiency).
---------------------------------------------------------------------------

The average of the emissions from the best performing sources are
used to calculate the floor, and an emissions variability factor is
added. For incinerators, cement kilns, and lightweight aggregate kilns
where we may have historical compliance test emissions data from
several test campaigns for a source, three approaches are considered to
select representative emissions for each best performing source: (1)
The highest compliance test emissions from any test campaign; (2) the
average of the highest compliance test emissions from all test
campaigns; and (3) the highest emissions during the most recent
compliance test campaign. By identifying the best performers based on
compliance test emissions from the test campaign with the lowest
emissions and calculating the floor using compliance test emissions
under these alternative approaches, emissions variability is addressed
in part.\76\
---------------------------------------------------------------------------

\76\ This approach for partially accounting for emissions
variability is effective only for those incinerators, cement kilns,
and lightweight aggregate kilns for which we have emissions data for
more than one test campaign.
---------------------------------------------------------------------------

Emissions variability is accounted for by adding an emissions
variability factor to the average emissions for the best performing
sources. The variability factor is a measure of the average run-to-run
variability for the test conditions for the best performing sources.
The variability factor is determined as the upper confidence limit
(calculated at the 99% confidence interval) around the mean of the runs
for each test condition for each best performer. (For sources with more
than one compliance test condition, the variability factor for each
source is first determined as the average of the variabilities
associated with each compliance test condition).\77\ The upper
confidence limits are averaged across the best performing sources, and
the average confidence limit is added to the average emissions from the
best performers to identify the floor.
---------------------------------------------------------------------------

\77\ We do not use this step in our statistical analysis because
we identify one test condition only as being representative of the
emissions for each source. Alternatively, ETC's approach includes an
option where the average of the historical compliance test
conditions is considered for Phase I sources. Under this option,
ETC's approach considers the average run-to-run variability for
those historical compliance tests.
---------------------------------------------------------------------------

We invite comment as to whether this alternative approach is
appropriate. We calculated alternative floor levels for new and
existing sources with minor adjustments.\78\ We present the results of
applying that approach in Table 6 below. See USEPA ``Draft Technical
Support Document for HWC MACT Replacement Standards, Volume III:
Selection of MACT Standards,'' March 2004, Chapters 12 and 21, for more
information on how we applied this approach to our data base.
---------------------------------------------------------------------------

\78\ Note that we modified part of ETC's suggested methodology
in some instances, which has resulted in our calculated floor levels
to differ from ETC's calculated floor levels. These modifications
are discussed in USEPA ``Draft Technical Support Document for HWC
MACT Replacement Standards, Volume III: Selection of MACT
Standards,'' March 2004, Chapter 12.

Table 6.--Floor Levels for Existing Sources Under the Modified ETC Approach
--------------------------------------------------------------------------------------------------------------------------------------------------------
Incinerators
-------------------------- Lightweight Solid fuel- Liquid fuel-
Data base Excluding Cement kilns aggregate fired fired
All speciality kilns boilers boilers
units
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mercury ([mu]g/dscm)................... Avg of historical CT data 130 (308) 130 (308) 48 37 ........... ...........
\1\ \1\
Most recent CT data...... 130 (308) 130 (308) 40 31 14 4.8
\1\ \1\
Highest of historical CT 130 (308) 130 (308) 68 45 ........... ...........
data. \1\ \1\
----------------------------------------
Particulate Matter (gr/dscf)........... Avg of historical CT data 0.0043 0.0043 0.025 0.017 ........... ...........
Most recent CT data...... 0.0043 0.0043 0.025 0.017 0.11 0.0090
Highest of historical CT 0.0043 0.0043 0.030 (0.032) 0.017 ........... ...........
data. \1\
----------------------------------------
Semivolatile Metals ([mu]g/dscm)....... Avg of historical CT data 53 32 230 250 (901) \1\ ........... ...........
Most recent CT data...... 53 32 160 250 (746) \1\ 230 8.2
Highest of historical CT 53 32 300 250 (1208) \1\ ........... ...........
data.
----------------------------------------
Low Volatile Metals ([mu]g/dscm)....... Avg of historical CT data 39 46 51 110 (119) \1\ ........... ...........
Most recent CT data...... 39 36 42 110 (129) \1\ 320 52
Highest of historical CT 39 56 56 \1\ 110 (133) \1\ ........... ...........
data.
----------------------------------------
Total Chlorine (ppmv).................. Avg of historical CT data 1.4 1.8 85 600 (1655) \1\ ........... ...........
Most recent CT data...... 1.4 1.8 86 600 (1811) \1\ 410 3.2
Highest of historical CT 1.4 1.8 89 600 (1823) \1\ ........... ...........
data.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: ``CT'' means Compliance Test.

[[Page 21238]]

\1\ Floor would be capped by the Interim Standards. Number in parentheses represents the calculated floor level, the number preceding is the ``capped''
interim standard level.

5. What Is Alternative Option 5, and What Is the Rationale?
Alternative Option 5 would use system removal efficiency (SRE) to
identify the best performing sources for the mercury, semivolatile
metals, low volatile metals, and total chlorine floor levels. This is
similar to the approach we propose to establish the total chlorine
standard for hydrochloric acid production furnaces. See discussion in
Part Two, Section VI.A.2.b.
Floor levels would be expressed as an SRE or an emission
concentration where the emission concentration is based on the
emissions achieved by the best performing SRE sources.\79\ A source
could elect to comply with either floor. An emissions floor as an
alternative to the SRE floor is appropriate because a source may be
achieving emission levels lower than those achieved by the best
performing SRE sources even though it may not be achieving MACT floor
SRE. For example, a source may be achieving low emissions without
achieving MACT SRE by using superior feedrate control.
---------------------------------------------------------------------------

\79\ We note that an SRE option, in some form, could be added to
any of the emission-based approaches previously discussed.
---------------------------------------------------------------------------

The SRE floor is an SRE that the average of the best performing SRE
sources could be expected to achieve in 99 of 100 future tests when
operating under the conditions used to establish the SRE.\80\ The
emissions floor is a stack gas concentration, or thermal emission
concentration for source categories that burn hazardous waste fuels,
that the average of the best performing SRE sources could be expected
to achieve in 99 of 100 future tests when operating under the
conditions used to establish the SRE and emission level.
---------------------------------------------------------------------------

\80\ Note that we only considered SREs associated with emission
values designated as compliance test (CT) in the database. See USEPA
``Draft Technical Support Document for HWC MACT Replacement
Standards, Volume III: Selection of MACT Standards,'' March 2004,
Chapters 11 and 20, for more information.
---------------------------------------------------------------------------

We note that this approach is not applicable for situations where
sources in a source category do not use back-end control to control
metals or total chlorine. For example, cement kilns do not use back-end
control to control mercury or total chlorine.\81\
---------------------------------------------------------------------------

\81\ Although the alkalinity in cement kiln raw materials helps
control total chlorine emissions, we are concerned that the system
removal efficiencies achieved may not be readily reproducible.
---------------------------------------------------------------------------

This approach is also not applicable for situations where our data
base is comprised of normal emissions data. As discussed previously,
SREs calculated from normal test conditions may be unreliable because a
small error in the feedrate calculation at low feedrates can have a
substantial impact on the calculated SRE.
In situations where this SRE-based approach is not applicable, we
would use an alternative approach to identify MACT floor, such as the
Emissions approach.
Floor levels for existing sources under this approach are presented
in Table 7.
We also investigated a variation of this approach where sources
with atypically high feedrates for metals or chlorine are excluded from
the calculation of the alternative emission level. This variation may
be appropriate to ensure that sources with high feedrates do not drive
the alternative emission concentration-based floor inappropriately high
even though the source may be a best performing SRE source. Under this
variation, note that sources with high feedrates are used, however, to
identify the best performing SRE sources and MACT SRE. This is because
sources with the highest feedrates may employ the best performing back-
end control systems to meet current standards or otherwise control
emissions. As a measure of atypically high feedrates, we use the 99th
upper percentile feedrate around the mean of feedrate data in the data
set available for the analysis. To ensure that we continue to use 5
sources or 12 percent of sources to calculate the emission
concentration-based floor under this variation, we replace a best
performing SRE source that is screened out of the concentration-based
floor analysis because of high feedrates with the source with the next
best SRE.\82\
---------------------------------------------------------------------------

\82\ Since sources with atypically high feedrates may still have
low emissions, sources with hazardous waste feed control levels
above the threshold are flagged, but not immediately removed from
the data set. Sources' SREs are ranked from best to worst, initially
choosing the best ranked 5 or 12% of sources as the interim MACT
pool. The remaining sources are temporarily set aside, and the
sources comprising the interim MACT pool are ranked again from
lowest to highest emissions. Sources from the interim MACT pool that
have been flagged due to having feedrates above the upper 99th
percentile are systematically (from highest to lowest emissions)
removed from the MACT pool and replaced with sources with the next
highest ranked SREs if the emissions from the next best source
initially excluded from the interim MACT pool has lower emissions.
The sources comprising the revised interim MACT pool now become the
final MACT pool. Emissions from those sources are again used to
calculate the MACT floor, with the resulting MACT floor again
expressed as an emission standard.
---------------------------------------------------------------------------

Floor levels for existing sources under this feedrate-screened
variation are presented in Table 8.
We invite comment on these alternative floor approaches. For more
information on how the approach would work, see USEPA ``Draft Technical
Support Document for HWC MACT Replacement Standards, Volume III:
Selection of MACT Standards,'' March 2004, Chapters 13 and 22.

[[Page 21239]]

Table 7.--Floor Levels for Existing Sources Under Alternative Option 5
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mercury Semivolatile metals Low volatile metals Total chlorine
-------------------------------------------------------------------------------------------------------------------------------------
Emissions Emission Emission Emission
Source category -------------------- concentration concentration concentration
SRE \1\ SRE \1\ -------------------- SRE \1\ -------------------- SRE \1\ ---------------------
Stack Thermal Stack Thermal Stack Thermal Stack gas Thermal
gas \2\ \3\ gas \2\ \3\ gas \2\ \3\ \2\ \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
Incinerators.................. 27 20,000 n/a \8\ 99.89 74 n/a \8\ 99.969 33 n/a \8\ 99.990 3.1 n/a \8\
\9\
-----------
Cement Kilns.................. n/a 4, 5 99.966 71 140 99.989 11 22 n/a 4, 5
-----------
Lightweight Aggregate Kilns... n/a 4, 6 99.78 330 310 99.89 100 95 n/a 4, 6
-----------
Solid Fuel-Fired Boilers...... 11 ........ n/a \8\ 99.78 180 n/a \8\ 97.9 230 n/a \8\ n/a 4, 5
-----------
Liquid Fuel-Fired Boilers..... n/a \4\
n/a \4\ 90.4 \7\ 27 \7\ 45 \7\ 99.70 25 55
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ SRE is system removal efficiency expressed as a percent.
\2\ Stack gas concentration is expressed in [mu]g/dscm for all except total chlorine, which is expressed as ppmv.
\3\ Thermal emission is expressed in lb/trillion Btu, except total chlorine which is expressed in lb/billion Btu.
\4\ Unable to determine SRE due to normal feedrate data.
\5\ No SRE due to no reliable back-end control.
\6\ Only one source has back-end control.
\7\ LVM Standards for liquid fuel-fired boilers are for Chromium, only.
\8\ Thermal emissions not appropriate for source categories with sources that do not burn hazardous waste fuels.
\9\ We believe this methodology yields inappropriate MACT mercury floors for incinerators because we have only 11 compliance test conditions, and the best
performers spiked uncharacteristically high levels of mercury during their compliance test.

Table 8.--Floor Levels for Existing Sources Under Alternative Option 5 With High Feedrate Screen
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mercury Semivolatile metals Low volatile metals Total chlorine
-------------------------------------------------------------------------------------------------------------------------------------
Emissions Emission Emission Emission
Source category -------------------- concentration concentration concentration
SRE \1\ SRE \1\ -------------------- SRE \1\ -------------------- SRE \1\ -------------------
Stack Thermal Stack Thermal Stack Thermal Stack gas Thermal
gas \2\ \3\ gas \2\ \3\ gas \2\ \3\ \2\ \3\
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
Incinerators.................. 27 7,500 n/a \8\ 99.89 64 n/a \8\ 99.969 29 n/a \8\ 99.990 1.3 n/a \8\
\9\
-----------
Cement Kilns.................. n/a 4, 5 99.966 65 130 99.989 11 18 n/a 4, 5
-----------
Lightweight Aggregate Kilns... n/a 4, 6 99.78 330 310 99.89 100 95 n/a 4, 6
-----------
Solid Fuel-Fired Boilers...... 11 ........ n/a \8\ 99.78 180 n/a \8\ 97.9 230 n/a \8\ n/a 4, 5
-----------
Liquid Fuel-Fired Boilers..... n/a \4\
n/a \4\ 90.4 \7\ 27 \7\ 110 \7\ 99.70 23 55
----------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ SRE is system removal efficiency expressed as a percent.
\2\ Stack gas concentration is expressed in [mu]g/dscm for all except total chlorine, which is expressed as ppmv.
\3\ Thermal emission is expressed in lb/trillion Btu, except total chlorine which is expressed in lb/billion Btu.
\4\ Unable to determine SRE due to normal feedrate data.
\5\ No SRE due to no reliable back-end control.
\6\ Only one source has back-end control.
\7\ LVM Standards for liquid fuel-fired boilers are for Chromium, only.
\8\ Thermal emissions not appropriate for source categories with sources that do not burn hazardous waste fuels.
\9\ We believe this methodology yields inappropriate MACT mercury floors for incinerators because we have
only 11 compliance test conditions, and the best performers spiked
uncharacteristically high levels of mercury during the their compliance test.

[[Page 21240]]

VII. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Incinerators?

The proposed standards for existing and new incinerators that burn
hazardous waste are summarized in the table below. See proposed Sec.
63.1219.

Proposed Standards for Existing and New Incinerators
------------------------------------------------------------------------
Emission standard \1\
Hazardous air pollutant or -------------------------------------------
surrogate Existing sources New sources
------------------------------------------------------------------------
Dioxin and furan--sources 0.28 ng TEQ/dscm.... 0.11 ng TEQ/dscm.
equipped with waste heat
boilers or dry air
pollution control system
\2\.
Dioxin and furan--sources 0.2 ng TEQ/dscm; or 0.20 ng TEQ/dscm.
not equipped with waste 0.40 ng TEQ/dscm
heat boilers or dry air and temperature at
pollution control system inlet to the
\2\. initial particulate
matter control
device <=400[deg]F.
Mercury..................... 130 [mu]g/dscm...... 8.0 [mu]g/dscm.
Particulate matter.......... 34 mg/dscm (0.015 gr/ 1.6 mg/dscm (0.00070
dscf). gr/dscf).
Semivolatile metals......... 59 [mu]g/dscm....... 6.5 [mu]g/dscm.
Low volatile metals......... 84 [mu]g/dscm....... 8.9 [mu]g/dscm.
Hydrogen chloride and 1.5 ppmv or the 0.18 ppmv or the
chlorine gas \3\. alternative alternative
emission limits emission limits
under Sec. under Sec.
63.1215. 63.1215.
Hydrocarbons \4,5\.......... 10 ppmv (or 100 ppmv 10 ppmv (or 100 ppmv
carbon monoxide). carbon monoxide).
Destruction and removal For existing and new sources, 99.99% for
efficiency. each principal organic hazardous
constituent (POHC). For sources burning
hazardous wastes F020, F021, F022, F023,
F026, or F027, however, 99.9999% for each
POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen dry basis.
\2\ A wet air pollution system followed by a dry air pollution control
system is not considered to be a dry air pollution control system for
purposes of this standard. A dry air pollution systems followed a wet
air pollution control system is considered to be a dry air pollution
control system for purposes of this standard.
\3\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\4\ Sources that elect to comply with the carbon monoxide standard must
demonstrate compliance with the hydrocarbon standard during the
comprehensive performance test.
\5\ Hourly rolling average. Hydrocarbons reported as propane.

A. What Are the Proposed Standards for Dioxin and Furan?

The proposed standards for dioxin/furan for sources equipped with
dry air pollution control devices and/or waste heat boilers are 0.28 ng
TEQ/dscm for existing sources and 0.11 ng TEQ/dscm for new sources. For
incinerators using either wet air pollution control or no air pollution
control devices, the proposed standards for dioxin/furan are 0.20 ng
TEQ/dscm or 0.40 ng TEQ/dscm while limiting the temperature at the
inlet to the particulate matter control device to less than 400 [deg]F
for existing sources and 0.20 ng TEQ/dscm for new sources.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Dioxin and furan emissions for existing incinerators are currently
limited by Sec. 63.1203(a)(1) to 0.20 ng TEQ/dscm; or 0.40 ng TEQ/dscm
provided that the combustion gas temperature at the inlet to the
initial particulate matter control device is limited to 400 [deg]F or
less. (For purposes of compliance, operation of a wet air pollution
control system is presumed to meet the 400 [deg]F or lower
requirement.) This standard was promulgated in the Interim Standards
Rule (See 67 FR at 6796, February 13, 2002).
Since promulgation of the September 1999 final rule, we have
obtained additional dioxin/furan emissions data. We now have dioxin/
furan emissions data for over 55 sources. The emissions in our data
base range from less than 0.001 to 34 ng TEQ/dscm.
As discussed in Part Two, Section II, we assessed whether
incinerators equipped with dry air pollution control devices and/or
waste heat boilers have statistically different emissions than sources
with either wet air pollution control or no air pollution control
equipment.\83\ Our statistical analysis indicates dioxin/furan
emissions between these types of incinerators are significantly
different. (As we explained there, these differences relate to
differences in dioxin/furan formation mechanisms, not pollution control
device efficiency.) Therefore, we believe subcategorization is
warranted for this emission standard and we are proposing separate
floor levels.
---------------------------------------------------------------------------

\83\ A source with a wet air pollution system followed by a dry
air pollution control system is not considered to be a dry air
pollution control system for purposes of this standard, while a
source with a dry air pollution system followed a wet air pollution
control system is considered to be a dry air pollution control
system. In addition, we note that a spray dryer is not considered to
be a wet air pollution control system for purposes of
subcategorization.
---------------------------------------------------------------------------

To identify the floor level for incinerators equipped with dry air
pollution control equipment and/or waste heat boilers, we evaluated the
compliance test emissions data associated with the most recent test
campaign using the Emissions Approach described in Part Two, Section
VI. The calculated floor is 0.28 ng TEQ/dscm, which considers emissions
variability. This is an emission level that the average of the best
performing sources could be expected to achieve in 99 of 100 future
tests when operating under conditions identical to the compliance test
conditions during which the emissions data were obtained. The
calculated floor level of 0.28 ng TEQ/dscm is based on five best
performing sources that achieved this floor level either by the use of
temperature control at the inlet to dry air pollution control device
and good combustion or by the use of activated carbon injection. The
single best performer is equipped with a dry air pollution control
system and a waste heat boiler, and uses activated carbon injection,
good combustion, and temperature control to control dioxin/furan
emissions. The remaining four

[[Page 21241]]

best performers are equipped with dry air pollution systems but do not
have waste heat recovery boilers. Two of these sources use activated
carbon, good combustion, and temperature control to control dioxin/
furan emissions.\84\ The other two without waste heat recovery boilers
use a combination of good combustion and temperature control to control
emissions.
---------------------------------------------------------------------------

\84\ One source uses an activated carbon injection system, and
the other uses a carbon bed.
---------------------------------------------------------------------------

We then judged the relative stringency of the calculated floor
level to the interim standard to determine if the proposed floor level
needed to be ``capped'' by the current interim standard to ensure the
proposed floor level is not less stringent than an existing federal
emission standard. A comparison of the calculated floor level of 0.28
ng TEQ/dscm to the interim standard--0.20 ng TEQ/dscm or 0.40 ng TEQ/
dscm provided that the combustion gas temperature at the inlet to the
initial particulate matter control device is limited to less than 400
[deg]F--indicates that a floor level of 0.28 ng TEQ/dscm is more
stringent than the current interim standard. This judgment is based on
our belief that the majority of these incinerators are currently
complying with the 0.40 ng TEQ/dscm and temperature limitation portion
of the interim standard.\85\ We estimate that this emission level is
being achieved by 71% of sources and would reduce dioxin/furan
emissions by 0.28 grams per year.
---------------------------------------------------------------------------

\85\ We request comment, however, on whether this judgment is
correct. If an incinerator is operated with a dry air pollution
control device inlet temperature greater than 400 [deg]F, then it
may be appropriate to instead require sources to comply with the
more stringent of the two standards, that is, 0.20 ng TEQ/dscm.
---------------------------------------------------------------------------

We also considered whether to further subcategorize based on
whether the incinerator is equipped with a waste heat recovery boiler
or dry air pollution control device. Our analysis determined that the
dioxin/furan emissions from incinerators with waste heat recovery
boilers are not statistically different from those equipped with dry
air pollution control systems. We propose, therefore, that further
subcategorization is not necessary given that incinerators using either
waste heat recovery boilers or dry air pollution control systems can
readily achieve the calculated floor level using control technologies
demonstrated by the best performing sources.
For sources with either wet air pollution control systems or no air
pollution control equipment, but are not equipped with a heat recovery
boiler, we contemplated identifying an emission limit but instead rely
on surrogates for control of organic HAP, namely good combustion
practices, to be demonstrated by complying with the carbon monoxide or
hydrocarbon emissions standard and compliance with the destruction and
removal efficiency standard.\86\ We believe that it would be
inappropriate to establish a numerical dioxin/furan floor level for
sources with wet or no air pollution control systems because the floor
emission level would not be replicable by the best performing sources
nor duplicable by other sources. Dioxin/furan formation mechanisms are
complex. Sources with wet or no air pollution control devices may have
difficulty complying with a numerical dioxin/furan limit that is based
on the lowest emitting dioxin/furan sources within this subcategory
because there is not a demonstrated floor control technology that these
sources can use to ``dial in'' to achieve a given emission level.
Moreover, dioxin/furan emissions could result from operation under poor
combustion conditions and formation on particulate matter surfaces in
duct work, on heat recovery boiler tubes, and on particulates entrained
in the combustion gas stream. As a result, we would instead identify
floor control for these sources to be operating under good combustion
practices by complying with the destruction and removal efficiency and
carbon monoxide/hydrocarbon standards.
---------------------------------------------------------------------------

\86\ Use of ``good combustion practices'' does not necessarily
preclude significant dioxin/furan formation. Our data base suggests,
however, that incinerators using wet air pollution control systems
achieve dioxin/furan emissions less than 0.40 ng TEQ/dscm. See
USEPA, ``Draft Technical Support Document for HWC MACT Replacement
Standards, Volume III: Selection of MACT Standards,'' March 2004, Chapter 2.
---------------------------------------------------------------------------

Though MACT floor for these units is operating under good
combustion practices, there is a regulatory limit which is relevant in
identifying the floor level. Hazardous waste incinerators are complying
with an interim standard for dioxin/furan--an emission limit of 0.20 ng
TEQ/dscm or, alternatively, 0.40 ng TEQ/dscm provided that the
combustion gas temperature at the inlet to the initial particulate
matter control device is limited to 400 [deg]F or less--that fixes a
level of performance for the source category. Given that all sources
are meeting this interim standard and that the interim standard is
judged as more stringent than a MACT floor of ``good combustion
practices,'' the dioxin/furan floor level can be no less stringent than
the current regulatory limit.\87\ Therefore, the proposed floor level
for incinerators with either wet air pollution control systems or no
air pollution control equipment that are not equipped with a heat
recovery boiler is either 0.20 ng TEQ/dscm or 0.40 ng TEQ/dscm provided
that the combustion gas temperature at the inlet to the initial
particulate matter control device is limited to 400 [deg]F or less.
This emission level is currently being achieved by all sources because
the interim standard is an enforceable standard currently in effect.
---------------------------------------------------------------------------

\87\ Even though all sources have recently demonstrated
compliance with the interim standards, the dioxin/furan data in our
data base preceded the compliance demonstration.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated beyond-the-floor standards based on the use of control
technology which removes dioxin/furan, namely use of an activated
carbon injection system or a carbon bed system as beyond-the-floor
control for further reduction of dioxin/furan emissions. Activated
carbon is currently used at three incinerators to control dioxin/furan.
We evaluated a beyond-the-floor level of 0.10 ng TEQ/dscm for all
incinerators, which represents a 65-75% reduction in dioxin/furan
emissions from the floor level. We selected this level because it
represents a level that is considered routinely achievable with
activated carbon.\88\
---------------------------------------------------------------------------

\88\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume V: Emissions Estimates and Engineering
Costs,'' March 2004, Chapter 4.3.
---------------------------------------------------------------------------

For incinerators equipped with dry air pollution control equipment
and/or waste heat boilers, the national incremental annualized
compliance cost for these sources to meet the beyond-the-floor level
rather than comply with the floor controls would be approximately $2.2
million and would provide an incremental reduction in dioxin/furan
emissions beyond the floor level controls of 0.5 grams TEQ per year.
Nonair quality health and environmental impacts and energy effects were
evaluated to estimate the impacts between activated carbon injection
and carbon beds and controls likely to be used to meet the floor level.
We estimate that this beyond-the-floor option would increase the amount
of hazardous waste generated by 1,500 tons per year in addition to
using an additional 3 million kW-hours per year beyond the requirements
to achieve the floor level. The costs associated with these hazardous
waste treatment/disposal and energy impacts are accounted for in the
national annualized compliance cost estimates. Therefore, based on
these factors and costs of approximately $4.4 million per

[[Page 21242]]

additional gram of dioxin/furan removed, we are not proposing a beyond-
the-floor standard based on activated carbon injection and carbon bed
systems.
For sources with either wet air pollution control systems or no air
pollution control equipment that are not equipped with a heat recovery
boiler, the national incremental annualized compliance cost for these
sources to meet the beyond-the-floor level would be approximately $3.9
million and would provide an incremental reduction in dioxin/furan
emissions beyond the MACT floor controls of 0.35 grams TEQ per year.
Nonair quality health and environmental impacts and energy effects were
also evaluated. We estimate that this beyond-the-floor option would
increase the amount of hazardous waste generated by 700 tons per year.
The option would also require sources to use an additional 2 million
kW-hours per year and 70 million gallons of water beyond the
requirements to achieve the floor level. Therefore, based on these
factors and costs of approximately $11 million per additional gram of
dioxin/furan removed, we are not proposing a beyond-the-floor standard
based on activated carbon injection and carbon bed systems.
3. What Is the Rationale for the MACT Floor for New Sources?
Dioxin and furan emissions for new incinerators are currently
limited by Sec. 63.1203(b)(1) to 0.20 ng TEQ/dscm. This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796, February
13, 2002).
For incinerators equipped with dry air pollution control equipment
and/or waste heat boilers, the calculated floor level is 0.11 ng TEQ/
dscm, which considers variability. This is an emission level that the
single best performing source identified using the Emissions Approach
could be expected to achieve in 99 out of 100 future tests when
operating under conditions identical to the compliance test conditions
during which the emissions data were obtained.
For sources with either wet air pollution control systems or no air
pollution control equipment that are not equipped with a heat recovery
boiler, as previously discussed for existing sources, we believe that
it would be inappropriate to establish numerical dioxin/furan emission
for these sources. We would instead identify floor control for these
sources to be operating under good combustion practices by complying
with the destruction and removal efficiency and carbon monoxide/
hydrocarbon standards.
Though MACT floor for these units is operating under good
combustion practices, there is a regulatory limit which is relevant in
identifying the floor level. New hazardous waste incinerators are
subject to an interim emission standard for dioxin/furan of 0.20 ng
TEQ/dscm. Given that the interim standard is judged more stringent than
a MACT floor of ``good combustion practices,'' the dioxin/furan floor
level can be no less stringent than the current regulatory limit.
Therefore, the proposed floor level for incinerators with either wet
air pollution control systems or no air pollution control equipment
that are not equipped with a heat recovery boiler is 0.20 ng TEQ/dscm.
Therefore, we are proposing the current interim standard of 0.20 ng
TEQ/dscm as the floor level for new sources.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated beyond-the-floor standards based on the use of a
carbon bed system to achieve additional removal of dioxin/furan. Given
the relatively low dioxin/furan levels at the floor, we made a
conservative assumption that the use of a carbon bed will provide an
additional 50% dioxin/furan control. We applied this removal efficiency
to the dioxin/furan floor levels to identify the beyond-the-floor levels.
For a new incinerator with average gas flowrate equipped with dry
air pollution control equipment and/or a waste heat boiler, the
national incremental annualized compliance cost to meet the beyond-the-
floor level of 0.06 ng TEQ/dscm rather than comply with the floor
controls would be approximately $0.22 million and would provide an
incremental reduction in dioxin/furan emissions beyond the floor level
controls of 0.013 grams TEQ per year. Nonair quality health and
environmental impacts and energy effects were evaluated. Therefore,
based on these factors and costs of approximately $17 million per
additional gram of dioxin/furan removed, we are not proposing a beyond-
the-floor standard based on activated carbon bed systems.
For a source with either a wet air pollution control system or no
air pollution control equipment that is not equipped with a heat
recovery boiler, the national incremental annualized compliance cost
for a new incinerator with an average gas flowrate to meet a beyond-
the-floor level of 0.10 ng TEQ/dscm would be approximately $0.22
million and would provide an incremental reduction in dioxin/furan
emissions beyond the MACT floor controls of 0.024 grams TEQ per year.
Considering the nonair quality health and environmental impacts and
energy effects in addition to costs of approximately $9.3 million per
additional gram of dioxin/furan removed, we are not proposing a beyond-
the-floor standard based on a carbon bed system.

B. What Are the Proposed Standards for Mercury?

We are proposing to establish standards for existing and new
incinerators that limit emissions of mercury to 130 [mu]g/dscm and 8
[mu]g/dscm, respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Mercury emissions for existing incinerators are currently limited
to 130 [mu]g/dscm by Sec. 63.1203(a)(2). This standard was promulgated
in the Interim Standards Rule (See 67 FR at 6796).
We have both normal and compliance test emissions data for over 50
sources. For several sources, we have emissions data from more than one
test campaign. The mercury stack emissions in our data base range from
less than 1 to 35,000 [mu]g/dscm, which are expressed as mass of
mercury per unit volume of stack gas.
To identify the floor level, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 610 [mu]g/dscm, which
considers emissions variability. Even though all sources have recently
demonstrated compliance with the interim standard of 130 [mu]g/dscm,
all the mercury emissions data in our data base precede initial
compliance with these interim standards. As a result, the calculated
floor level of 610 [mu]g/dscm is less stringent than the interim
standard, which is a regulatory limit relevant in identifying the floor
level (so as to avoid any backsliding from a current level of
performance achieved by all incinerators, and hence, the level of
minimal stringency at which EPA could calculate the MACT floor).
Therefore, we are proposing the floor level as the current emission
standard of 130 [mu]g/dscm. This emission level is currently being
achieved by all sources.
We invite comment on an alternative approach to identify the floor
level using available normal emissions data instead of the compliance
test data. For reasons we discussed above in Part Two, our floor-
setting methodology favors compliance test data over normal emissions
data. However, there are available more mercury emissions data

[[Page 21243]]

characterized as normal--over 40 test conditions--than the eleven
compliance test results. Given that the data base includes considerably
more normal emissions than compliance test data, we invite comment on
whether the floor analysis should be based on the normal emissions data
instead of the compliance test data. The floor level considering the
normal data using the Emissions Approach is 7.8 [mu]g/dscm, which
considers emissions variability. If we were to adopt such an approach,
we would require sources to comply with the limit on an annual basis
because the floor analysis is based on normal emissions data. Under
this approach, compliance would not be based on the use of a total
mercury continuous emissions monitoring system because these monitors
have not been adequately demonstrated as a reliable compliance
assurance tool at all types of incinerator sources. Instead, a source
would maintain compliance with the mercury standard by establishing and
complying with short-term limits on operating parameters for pollution
control equipment and annual limits on maximum total mercury feedrate
in all feedstreams.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of mercury: (1) Activated carbon injection; and (2) control of mercury
in the hazardous waste feed.
Use of Activated Carbon Injection. We evaluated activated carbon
injection as beyond-the-floor control for further reduction of mercury
emissions. Activated carbon injection is currently being used at three
incinerators and has been demonstrated for controlling mercury and has
achieved efficiencies ranging from 80% to greater than 90% depending on
various factors such as injection rate, mercury speciation in the flue
gas, flue gas temperature, and carbon type. Given the limited
experience at hazardous waste combustion systems, we made a
conservative assumption that the use of activated carbon will provide
70% mercury control. We evaluated a beyond-the-floor level of 39 [mu]g/dscm.
The national incremental annualized compliance cost for
incinerators to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $7.1 million and would
provide an incremental reduction in mercury emissions beyond the MACT
floor controls of 0.39 tons per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
impacts between activated carbon injection and controls likely to be
used to meet the floor level. We estimate that this beyond-the-floor
option would increase the amount of hazardous waste generated by 1,800
tons per year and would require sources to use an additional 5.8
million kW-hours per year beyond the requirements to achieve the floor
level. The costs associated with these hazardous waste treatment/
disposal and energy impacts are accounted for in the national
annualized compliance cost estimates. Therefore, based on these factors
and costs of approximately $18 million per additional ton of mercury
removed, we are not proposing a beyond-the-floor standard based on
activated carbon injection.
Feed Control of Mercury in the Hazardous Waste. We also evaluated a
beyond-the-floor level of 100 [mu]g/dscm, which represents a 20%
reduction from the floor level. We chose a 20% reduction as a level
that represents the practicable extent that additional feedrate control
of mercury in hazardous waste (beyond feedrate control that may be
necessary to achieve the floor level) can be used and still achieve
modest emissions reductions.\89\ The national incremental annualized
compliance cost for incinerators to meet this beyond-the-floor level
rather than comply with the floor controls would be approximately $1.8
million and would provide an incremental reduction in mercury emissions
beyond the MACT floor controls of 0.11 tons per year. Nonair quality
health and environmental impacts and energy effects were also
evaluated. Therefore, based on these factors and costs of approximately
$17 million per additional ton of mercury removed, we are not proposing
a beyond-the-floor standard based on feed control of mercury in the
hazardous waste.
---------------------------------------------------------------------------

\89\ Ideally, a methodology to estimate costs of feed control
should consider lost revenues associated with hazardous wastes not
fired and costs to implement feed control of metals and chlorine. We
attempted to conduct such an analysis; however, we concluded that
there are too many uncertainties to do this analysis. Instead, we
developed an alternative approach to cost feed control of metals and
chlorine in the hazardous waste based on the assumption that a
source would not implement a feed control strategy if the costs
exceed the costs to retrofit an existing air pollution control
device. Thus, our cost estimates of feed control represent an upper
bound estimate on likely costs to control metals or chlorine in
hazardous waste. See USEPA, ``Draft Technical Support Document for
HWC MACT Replacement Standards, Volume V: Emission Estimates and
Engineering Costs,'' March 2004, Chapter 4.
---------------------------------------------------------------------------

For the reasons discussed above, we propose a mercury emissions
standard of 130 [mu]g/dscm for existing incinerators.
3. What Is the Rationale for the MACT Floor for New Sources?
Mercury emissions from new incinerators are currently limited to 45
[mu]g/dscm by Sec. 63.1203(b)(2). This standard was promulgated in the
Interim Standards Rule (See 67 FR at 6796).
The MACT floor for new sources for mercury would be 8 [mu]g/dscm,
which considers emissions variability. This is an emission level that
the single best performing source identified with the SRE/Feed Approach
considering compliance test data could be expected to achieve in 99 of
100 future tests when operating under conditions identical to the test
conditions during which the emissions data were obtained.
As we did for existing sources, we also invite comment on basing
the floor analysis on the normal emissions data using the Emissions
Approach. The floor level using the normal data is 0.70 [mu]g/dscm,
which considers emissions variability. If we were to adopt such an
approach, we would require sources to comply with the limit on an
annual basis because it is based on normal emissions data.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified two potential beyond-the-floor techniques for control
of mercury: (1) Use of a carbon bed; and (2) control of mercury in the
hazardous waste feed.
Carbon Bed System. We evaluated a carbon bed system as beyond-the-
floor control for further reduction of mercury emissions. Given the
relatively low floor level, we made a conservative assumption that the
use of a carbon bed system would provide 50% mercury control. The
incremental annualized compliance cost for a new incinerator with
average gas flow rate to meet a beyond-the-floor level of 4 [mu]g/dscm,
rather than comply with the floor level, would be approximately $0.22
million and would provide an incremental reduction in mercury emissions
of approximately 2.1 pounds per year. Nonair quality health and
environmental impacts and energy effects are accounted for in the
national annualized compliance cost estimates. Therefore, based on
these factors and costs of approximately $200 million per additional
ton of mercury removed, we are not proposing a beyond-the-floor
standard based on a carbon bed system.
Feed Control of Mercury in the Hazardous Waste. We also believe
that the expense for a reduction in mercury emissions based on further
control of mercury concentrations in the

[[Page 21244]]

hazardous waste is not warranted. A beyond-the-floor level of 6.4
[mu]g/dscm, which represents a 20% reduction from the floor level,
would result in a small incremental reduction in mercury emissions. For
similar reasons discussed above for existing sources, we likewise
conclude that a beyond-the-floor standard based on controlling the
mercury in the hazardous waste feed would not be justified because of
the costs and emission reductions. Therefore, we propose a mercury
standard of 8 [mu]g/dscm for new sources.

C. What Are the Proposed Standards for Particulate Matter?

We are proposing to establish standards for existing and new
incinerators that limit emissions of particulate matter to 0.015 and
0.00070 gr/dscf, respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Particulate matter emissions for existing incinerators are
currently limited to 0.015 gr/dscf (34 mg/dscm) by Sec. 63.1203(a)(7).
This standard was promulgated in the Interim Standards Rule (See 67 FR
at 6796). The particulate matter standard is a surrogate control for
the hazardous air pollutant metals antimony, cobalt, manganese, nickel,
and selenium.
We have compliance test emissions data for most incinerators. For
some sources, we have compliance test emissions data from more than one
compliance test campaign. Our data base of particulate matter stack
emission concentrations range from 0.0002 to 0.078 gr/dscf.
To identify the MACT floor for incinerators, we evaluated the
compliance test emissions data associated with the most recent test
campaign using the Air Pollution Control Technology Approach. The
calculated floor is 0.020 gr/dscf (46 mg/dscm), which considers
emissions variability. This is an emission level that the average of
the best performing sources could be expected to achieve in 99 of 100
future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. The calculated floor level of 0.020 gr/dscf is less stringent
than the interim standard of 0.015 gr/dscf, which is a regulatory limit
relevant in identifying the floor level (so as to avoid any backsliding
from a current level of performance achieved by all incinerators, and
hence, the level of minimal stringency at which EPA could calculate the
MACT floor). Therefore, we are proposing the floor level as the current
emission standard of 0.015 gr/dscf. This emission level is currently
being achieved by all sources.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated improved particulate matter control to achieve a
beyond-the-floor standard of 17 mg/dscm (0.0075 gr/dscf). For an
existing incinerator that needs a significant reduction in particulate
matter emissions, we assumed and costed a new baghouse to achieve the
beyond-the-floor level. If little or modest emissions reductions were
needed, then improved control was costed as design, operation, and
maintenance modifications of the existing particulate matter control
equipment.
The national incremental annualized compliance cost for
incinerators to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $3.9 million and would
provide an incremental reduction in particulate matter emissions beyond
the MACT floor of 48 tons per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
nonair quality health and environmental impacts between further
improvements to control particulate matter and controls likely to be
used to meet the floor level. We estimate that this beyond-the-floor
option would increase the amount of hazardous waste generated by 48
tons per year and would also require sources to use an additional 2.7
million kW-hours per year beyond the requirements to achieve the floor
level. The costs associated with these impacts are accounted for in the
national annualized compliance cost estimates. Therefore, based on
these factors and costs of approximately $81,000 per additional ton of
particulate matter removed, we are not proposing a beyond-the-floor
standard based on improved particulate matter control.
3. What Is the Rationale for the MACT Floor for New Sources?
Particulate matter emissions from new incinerators are currently
limited to 0.015 gr/dscf (34 mg/dscm) by Sec. 63.1203(b)(7). This
standard was promulgated in the Interim Standards Rule (See 67 FR at 6796).
The MACT floor for new sources for particulate matter would be 1.6
mg/dscm (0.00070 gr/dscf), which considers emissions variability. This
is an emission level that the single best performing source identified
with the Air Pollution Control Technology Approach could be expected to
achieve in 99 of 100 future tests when operating under operating
conditions identical to the test conditions during which the emissions
data were obtained.
As discussed in Part Two, Section II, we considered whether to
propose separate standards (subcategorize) for particulate matter for
several different potential subcategories such as government-owned
versus non-government incinerators and liquid injection versus solid
fuel-fired incinerators. We determined that the emission
characteristics from these potential subcategories are not
statistically different, and, therefore, separate standards for
particulate matter are not warranted. We request comment on whether
these subcategorization considerations capture the appropriate
differences in manufacturing process, emission characteristics, or
technical feasibility for particulate matter. We note, for example, the
single best performing source, which is the basis of the floor level
for new incinerators, is an incinerator used to decontaminate scrap
metal. Though we believe these sources are best performers because they
use highly efficient baghouses for the capture of particulate matter,
and, therefore, appropriate for inclusion in the analysis, we invite
comment on whether we have considered the appropriate subcategories for
particulate matter. We note that a floor level based on the second best
performing incinerator source would be 0.0021 gr/dscf.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated improved emissions control based on a state-of-the-art
baghouse using a high quality fabric filter bag material to achieve a
beyond-the-floor standard of 1.2 mg/dscm (0.0005 gr/dscf). The
incremental annualized compliance cost for a new incinerator to meet
this beyond-the-floor level, rather than comply with the floor level,
would be approximately $80,000 and would provide an incremental
reduction in particulate matter emissions of approximately 0.15 tons
per year. Nonair quality health and environmental impacts and energy
effects were also evaluated and are accounted for in the national
annualized compliance cost estimates. We estimate that this option
would require a new source to use an additional 0.2 million kW-hours
per year. For these reasons and a cost-effectiveness of $0.53 million
per ton of particulate matter removed, we are not proposing a beyond-
the-floor standard based on improved particulate matter control for new
incinerators. Therefore, we propose a particulate

[[Page 21245]]

matter standard of 1.6 mg/dscm for new sources.

D. What Are the Proposed Standards for Semivolatile Metals?

We are proposing to establish standards for existing and new
incinerators that limit emissions of semivolatile metals (cadmium and
lead) to 59 ug/dscm and 6.5 ug/dscm, respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Semivolatile metals emissions from existing incinerators are
currently limited to 240 ug/dscm by Sec. 63.1203(a)(3). This standard
was promulgated in the Interim Standards Rule (See 67 FR at 6796).
Incinerators control emissions of semivolatile metals with air
pollution control equipment and/or by controlling the feed
concentration of semivolatile metals in the hazardous waste.
We have compliance test emissions data for nearly 30 incinerators.
Semivolatile metal stack emissions range from approximately 4 to 29,000
ug/dscm. These emissions are expressed as mass of semivolatile metals
per unit volume of stack gas. Lead was usually the most significant
contributor to semivolatile emissions during compliance test conditions.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 59 ug/dscm, which considers
emissions variability. This is an emission level that the average of
the best performing sources could be expected to achieve in 99 of 100
future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 52%
of sources. The floor level would reduce semivolatile metals emissions
by 0.43 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of semivolatile metals: (1) Improved particulate matter control; and
(2) control of semivolatile metals in the hazardous waste feed.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of semivolatile metals. We evaluated a beyond-
the-floor level of 30 [mu]g/dscm, which is a 50% reduction from the
floor level, based on additional reductions of particulate matter
emissions by operating and maintaining existing control equipment to
have improved collection efficiency. The national incremental
annualized compliance cost for incinerators to meet this beyond-the-
floor level rather than comply with the floor controls would be
approximately $3.0 million and would provide an incremental reduction
in semivolatile metals emissions beyond the MACT floor controls of 190
pounds per year. Nonair quality health and environmental impacts and
energy effects were evaluated to estimate the impacts between further
improvements to control particulate matter and controls likely to be
used to meet the floor level. We estimate that this beyond-the-floor
option would increase the amount of hazardous waste generated by 50
tons per year and would require sources to use an additional 3.4
million kW-hours per year beyond the requirements to achieve the floor
level. The costs associated with these hazardous waste treatment and
energy impacts are accounted for in the national annualized compliance
cost estimates. Therefore, based on these factors and costs of
approximately $31 million per additional ton of semivolatile metals
removed, we are not proposing a beyond-the-floor standard based on
improved particulate matter control.
Feed Control of Semivolatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 47 [mu]g/dscm, which represents a
20% reduction from the floor level. We chose a 20% reduction as a level
that represents the practicable extent that additional feedrate control
of semivolatile metals in the hazardous waste can be used and still
achieve modest emissions reductions. The national incremental
annualized compliance cost for incinerators to meet this beyond-the-
floor level rather than comply with the floor controls would be
approximately $1.7 million and would provide an incremental reduction
in semivolatile metals emissions beyond the MACT floor of 90 pounds per
year. Nonair quality health and environmental impacts and energy
effects were also evaluated and are accounted for in the national
annualized compliance cost estimates. For these reasons and costs of
approximately $39 million per additional ton of semivolatile metals
removed, we are not proposing a beyond-the-floor standard based on feed
control of semivolatile metals in the hazardous waste.
For the reasons discussed above, we propose to establish the
emission standard for existing incinerators at 59 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
Semivolatile metals emissions from new incinerators are currently
limited to 120 [mu]g/dscm by Sec. 63.1203(b)(3). This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796).
The MACT floor for new sources for semivolatile metals would be 6.5
[mu]g/dscm, which considers emissions variability. This is an emission
level that the single best performing source identified with the SRE/
Feed Approach could be expected to achieve in 99 of 100 future tests
when operating under conditions identical to the test conditions during
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified two potential beyond-the-floor techniques for control
of semivolatile metals: (1) Improved control of particulate matter; and
(2) control of semivolatile metals in the hazardous waste feed.
Improved Particulate Matter Control. We evaluated a standard of 3.3
[mu]g/dscm, which is a 50% reduction from the floor level, based on a
state-of-the-art baghouse using a high quality fabric filter bag
material as beyond-the-floor control for further reductions in
semivolatile metals emissions. The incremental annualized compliance
cost for a new incinerator with an average gas flow rate to meet this
beyond-the-floor level, rather than comply with the floor level, would
be approximately $80,000 and would provide an incremental reduction in
semivolatile metals emissions of approximately 2 pounds per year.
Nonair quality health and environmental impacts and energy effects were
also evaluated and are included in the cost estimates. We estimate that
this option would require a new source to use an additional 0.2 million
kW-hours per year. For these reasons and costs of $94 million per ton
of semivolatile metals removed, we are not proposing a beyond-the-floor
standard based on improved particulate matter control for new sources.
Feed Control of Semivolatile Metals in the Hazardous Waste. We also
believe that the expense for a reduction in semivolatile metals
emissions based on further control of semivolatile metals
concentrations in the hazardous waste is not warranted. A beyond-the-
floor level of 5.2 [mu]g/dscm, which represents a 20% reduction from
the floor level, would result in little additional semivolatile metals
reductions. For similar reasons discussed above for existing sources, we

[[Page 21246]]

judge that a beyond-the-floor standard based on controlling the
semivolatile metals in the hazardous waste feed would not be justified
because of the costs and expected emission reductions. Therefore, we
propose a semivolatile metals standard of 6.5 [mu]g/dscm for new sources.

E. What Are the Proposed Standards for Low Volatile Metals?

We are proposing to establish standards for existing and new
incinerators that limit emissions of low volatile metals (arsenic,
beryllium, and chromium) to 84 [mu]g/dscm and 8.9 [mu]g/dscm, respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Low volatile metals emissions from existing incinerators are
currently limited to 97 [mu]g/dscm by Sec. 63.1203(a)(4). This
standard was promulgated in the Interim Standards Rule (See 67 FR at
6796). Incinerators control emissions of low volatile metals with air
pollution control equipment and/or by controlling the feed
concentration of low volatile metals in the hazardous waste.
We have compliance test emissions data for nearly 30 incinerators.
Low volatile metal stack emissions range from approximately 1 to 4,300
[mu]g/dscm. These emissions are expressed as mass of low volatile
metals per unit volume of stack gas.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 84 [mu]g/dscm, which
considers emissions variability. This is an emission level that the
average of the best performing sources could be expected to achieve in
99 of 100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 85%
of sources and would reduce low volatile metals emissions by 56 pounds
per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of low volatile metals: (1) Improved particulate matter control; and
(2) control of low volatile metals in the hazardous waste feed.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of low volatile metals. We evaluated a beyond-
the-floor level of 42 [mu]g/dscm, which is a 50% reduction from the
floor level, based on additional reductions of particulate matter
emissions by operating and maintaining existing control equipment to
have improved collection efficiency. The national incremental
annualized compliance cost for incinerators to meet this beyond-the-
floor level rather than comply with the floor controls would be
approximately $0.88 million and would provide an incremental reduction
in low volatile metals emissions beyond the MACT floor controls of 365
pounds per year. Nonair quality health and environmental impacts and
energy effects were evaluated to estimate the impacts between further
improvements to control particulate matter and controls likely to be
used to meet the floor level. We estimate that this beyond-the-floor
option would increase the amount of hazardous waste generated by 100
tons per year and would require sources to use an additional 0.7
million kW-hours per year beyond the requirements to achieve the floor
level. The costs associated with these impacts are accounted for in the
national annualized compliance cost estimates. Therefore, based on
these factors and costs of approximately $4.8 million per additional
ton of low volatile metals removed, we are not proposing a beyond-the-
floor standard based on improved particulate matter control.
Feed Control of Low Volatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 67 [mu]g/dscm, which represents a
20% reduction from the floor level. We chose a 20% reduction as a level
that represents the practicable extent that additional feedrate control
of low volatile metals in the hazardous waste can be used and still
achieve modest emissions reductions. The national incremental
annualized compliance cost for incinerators to meet this beyond-the-
floor level rather than comply with the floor controls would be
approximately $0.25 million and would provide an incremental reduction
in low volatile metals emissions beyond the MACT floor controls of 0.11
tons per year. Nonair quality health and environmental impacts and
energy effects were also evaluated and are accounted for in the
national annualized compliance cost estimates. Therefore, based on
these factors and costs of approximately $2.2 million per additional
ton of low volatile metals removed, we are not proposing a beyond-the-
floor standard based on feed control of low volatile metals in the
hazardous waste.
For the reasons discussed above, we propose to establish the
emission standard for existing incinerators at 84 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
Low volatile metal emissions from new incinerators are currently
limited to 97 [mu]g/dscm by Sec. 63.1203(b)(4). This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796).
The MACT floor for new sources for low volatile metals would be 8.9
[mu]g/dscm, which considers emissions variability. This is an emission
level that the single best performing source identified with the SRE/
Feed Approach could be expected to achieve in 99 of 100 future tests
when operating under conditions identical to the test conditions during
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified two potential beyond-the-floor techniques for control
of low volatile metals: (1) Improved control of particulate matter; and
(2) control of low volatile metals in the hazardous waste feed.
Improved Particulate Matter Control. We evaluated a standard of 4.5
[mu]g/dscm, which is a 50% reduction from the floor level, based on a
state-of-the-art baghouse using a high quality fabric filter bag
material as beyond-the-floor control for further reductions in low
volatile metals emissions. The incremental annualized compliance cost
for a new incinerator with average gas flowrate to meet this beyond-
the-floor level, rather than comply with the floor level, would be
approximately $80,000 and would provide an incremental reduction in low
volatile metals emissions of approximately 2.3 pounds per year. Nonair
quality health and environmental impacts and energy effects were also
evaluated and are included in the cost estimates. For these reasons and
costs of $69 million per ton of low volatile metals removed, we are not
proposing a beyond-the-floor standard based on improved particulate
matter control for new sources.
Feed Control of Low Volatile Metals in the Hazardous Waste. We also
believe that the expense associated with a reduction in low volatile
metals emissions based on further control of low volatile metals
concentrations in the hazardous waste is not warranted. A beyond-the-
floor level of 7.1 [mu]g/dscm, which represents a 20% reduction from
the floor level, would result in little additional low volatile metals
reductions. For similar reasons discussed above for existing sources, we

[[Continued on page 21247]]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]]
[[pp. 21247-21296]] National Emission Standards for Hazardous Air Pollutants:
Proposed Standards for Hazardous Air Pollutants for Hazardous Waste
Combustors (Phase I Final Replacement Standards and Phase II)
[[Continued from page 21246]]
[[Page 21247]]

judge that a beyond-the-floor standard based on controlling the low
volatile metals in the hazardous waste feed would not be cost-effective
or otherwise appropriate. Therefore, we propose a low volatile metals
standard of 8.9 [mu]g/dscm for new sources.

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?

We are proposing to establish standards for existing and new
incinerators that limit total chlorine emissions (hydrogen chloride and
chlorine gas, combined, reported as a chloride equivalent) to 1.5 and
0.18 ppmv, respectively. However, we are also proposing to establish
alternative risk-based standards, pursuant to CAA section 112(d)(4),
which a source could elect to comply with by in lieu of the MACT
emission standards for total chlorine. The emission limits would be
based on national exposure standards that ensure protection of public
health with an ample margin of safety. See Part Two, Section XIII for
additional details.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Total chlorine emissions from existing incinerators are limited to
77 ppmv by Sec. 63.1203(a)(6). This standard was promulgated in the
Interim Standards Rule (See 67 FR at 6796). Incinerators control
emissions of total chlorine with air pollution control equipment and/or
by controlling the feed concentration of chlorine in the hazardous waste.
We have compliance test emissions data for most incinerators. Total
chlorine emissions range from less than 1 ppmv to 460 ppmv.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 1.5 ppmv, which considers
emissions variability. This is an emission level that the best
performing feed control sources could be expected to achieve in 99 of
100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 11%
of sources and reductions to the floor level would reduce total
chlorine emissions by 286 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of total chlorine: (1) Improved control with wet scrubbing; and (2)
control of chlorine in the hazardous waste feed.
Use of Wet Scrubbing. We evaluated a beyond-the-floor level of 0.8
ppmv based on improved wet scrubbers that would include increasing the
liquid to gas ratio, increasing the liquor pH, and replacing the
existing packing material with new more efficient packing material. We
made a conservative assumption that an improved wet scrubber will
provide 50% total chlorine control beyond the controls needed to
achieve the floor level given the low total chlorine levels at the
floor. Applying this wet scrubbing removal efficiency to the total
chlorine floor level of 1.5 ppmv leads to a beyond-the-floor level 0.8
ppmv. The national incremental annualized compliance cost for
incinerators to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $1.7 million and would
provide an incremental reduction in total chlorine emissions beyond the
MACT floor controls of 6 tons per year. We also evaluated nonair
quality health and environmental impacts and energy effects between
improved wet scrubbers and controls likely to be used to meet the floor
level. We estimate that this beyond-the-floor option would increase the
amount of waste water generated by 270 million gallons per year. The
option would also require sources to use an additional 3.2 million kW-
hours per year and 270 million gallons of water beyond the requirements
to achieve the floor level. The costs associated with these impacts are
accounted for in the national annualized compliance cost estimates.
Therefore, based on these factors and costs of approximately $0.29
million per additional ton of total chlorine removed, we are not
proposing a beyond-the-floor standard based on improved wet scrubbing.
Feed Control of Chlorine in the Hazardous Waste. We also evaluated
a beyond-the-floor level of 1.2 ppmv, which represents a 20% reduction
from the floor level. We chose a 20% reduction as a level that
represents the practicable extent that additional feedrate control of
chlorine in hazardous waste can be used and still achieve appreciable
emissions reductions. The national incremental annualized compliance
cost for incinerators to meet this beyond-the-floor level rather than
comply with the floor controls would be approximately $0.69 million and
would provide an incremental reduction in total chlorine emissions
beyond the MACT floor controls of 2.5 tons per year. Nonair quality
health and environmental impacts and energy effects were also evaluated
and are accounted for in the national annualized compliance cost
estimates. Therefore, based on these factors and costs of approximately
$0.28 million per additional ton of total chlorine removed, we are not
proposing a beyond-the-floor standard based on feed control of chlorine
in the hazardous waste.
For the reasons discussed above, we propose to establish the
emission standard for existing incinerators at 1.5 ppmv.
3. What Is the Rationale for the MACT Floor for New Sources?
Total chlorine emissions from incinerators are currently limited to
21 ppmv by Sec. 63.1203(b)(6). This standard was promulgated in the
Interim Standards Rule (See 67 FR at 6796). The MACT floor for new
sources for total chlorine would be 0.18 ppmv, which considers
emissions variability. This is an emission level that the single best
performing source identified with the SRE/Feed Approach could be
expected to achieve in 99 of 100 future tests when operating under
conditions identical to the test conditions during which the emissions
data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified similar potential beyond-the-floor techniques for
control of total chlorine for new sources: (1) Use of improved wet
scrubbers; and (2) control of chlorine in the hazardous waste feed.
Use of Wet Scrubbing. We evaluated a beyond-the-floor level of 0.1
ppmv using wet scrubbers as beyond-the-floor control for further
reductions in total chlorine emissions. We made a conservative
assumption that an improved wet scrubber will provide 50% total
chlorine reductions beyond the controls needed to achieve the floor
level given the low total chlorine levels at the floor. The incremental
annualized compliance cost for a new incinerator with an average gas
flowrate to meet this beyond-the-floor level, rather than comply with
the floor level, would be approximately $0.2 million and would provide
an incremental reduction in total chlorine emissions of approximately
35 pounds per year. Nonair quality health and environmental impacts and
energy effects were also evaluated and are included in the cost
estimates. We estimate that this option would increase the amount of
wastewater generated by 50 million gallons per year and would require a
new source to use an additional 0.5 million kW-hours per year beyond
the requirements to achieve the floor level. For these reasons and

[[Page 21248]]

costs of $12 million per ton of chlorine removed, we are not proposing
a beyond-the-floor standard based on improved wet scrubbing control for
new sources.
Feed Control of Chlorine in the Hazardous Waste. We also believe
that the expense associated with a reduction in chlorine emissions
based on further control of chlorine concentrations in the hazardous
waste is not warranted. We considered a beyond-the-floor level of 0.14
ppmv, which represents a 20% reduction from the floor level. For
similar reasons discussed above for existing sources, we judge that a
beyond-the-floor standard based on controlling the chlorine in the
hazardous waste feed would not be cost-effective or otherwise
appropriate. Therefore, we propose a chlorine standard of 0.18 ppmv for
new sources.

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

Hydrocarbon and carbon monoxide standards are surrogates to control
emissions of organic hazardous air pollutants for existing and new
incinerators. The standards limit hydrocarbons and carbon monoxide
concentrations to 10 ppmv or 100 ppmv. See Sec. Sec. 63.1203(a)(5) and
(b)(5). Existing and new incinerators can elect to comply with either
the hydrocarbon limit or the carbon monoxide limit on a continuous
basis. Sources that comply with the carbon monoxide limit on a
continuous basis must also demonstrate compliance with the hydrocarbon
standard during the comprehensive performance test. However, continuous
hydrocarbon monitoring following the performance test is not required.
The rationale for these decisions are discussed in the September 1999
final rule (64 FR at 52900). We view the standards for hydrocarbons and
carbon monoxide as unaffected by the Court's vacature of the challenged
regulations in its decision of July 24, 2001. We therefore are not
proposing these standards for incinerators, but rather are mentioning
them here for the reader's convenience.

H. What Are the Standards for Destruction and Removal Efficiency?

The destruction and removal efficiency (DRE) standard is a
surrogate to control emissions of organic hazardous air pollutants
other than dioxin/furans. The standard for existing and new
incinerators requires 99.99% DRE for each principal organic hazardous
constituent, except that 99.9999% DRE is required if specified dioxin-
listed hazardous wastes are burned. See Sec. Sec. 63.1203(c). The
rationale for these decisions are discussed in the September 1999 final
rule (64 FR at 52902). We view the standards for DRE as unaffected by
the Court's vacature of the challenged regulations in its decision of
July 24, 2001. We therefore are not proposing these standards for
incinerators, but rather are mentioning them here for the reader's convenience.

VIII. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Cement Kilns?

In this section, the basis for the proposed emission standards is
discussed. See proposed Sec. 63.1220 The proposed emission limits
apply to the kiln stack gases, in-line kiln raw mill stack gases if
combustion gases pass through the in-line raw mill, and kiln alkali
bypass stack gases if discharged through a separate stack.\90\ The
proposed standards for existing and new cement kilns that burn
hazardous waste are summarized in the table below:
---------------------------------------------------------------------------

\90\ Currently, we are not aware of any preheater/preacalciner
kiln that vents its alkali bypass gases through a separate stack.

Proposed Standards for Existing and New Cement Kilns
------------------------------------------------------------------------
Emission standard \1\
Hazardous air pollutant or -------------------------------------------
surrogate Existing sources New sources
------------------------------------------------------------------------
Dioxin and furan \1\........ 0.20 ng TEQ/dscm; or 0.40 ng TEQ/dscm and
control of flue gas temperature not to
exceed 400[deg]F at the inlet to the
particulate matter control device.
=============================
Particulate Matter.......... 65 mg/dscm (0.028 gr/ 13 mg/dscm (0.0058
dscf). gr/dscf).
Semivolatile metals \3\..... 4.0 x 10-4 lb/MMBtu. 6.2 x 10-5 lb/MMBtu.
Low volatile metals \3\..... 1.4 x 10-5 lb/MMBtu. 1.4 x 10-5 lb/MMBtu.
Hydrogen chloride and 110 ppmv or the 78 ppmv or the
chlorine gas \4\. alternative alternative
emission limits emission limits
under Sec. under Sec.
63.1215. 63.1215.
Hydrocarbons: kilns without 20 ppmv (or 100 ppmv Greenfield kilns: 20
bypass \5,\ \6\. carbon monoxide) ppmv (or 100 ppmv
\5\. carbon monoxide and
50 ppmv \7\
hydrocarbons). All
others: 20 ppmv (or
100 ppmv carbon
monoxide) \5\.
Hydrocarbons: kilns with No main stack 50 ppmv \7\.
bypass; main stack \6,\ \8\. standard.
Hydrocarbons: kilns with 10 ppmv (or 100 ppmv 10 ppmv (or 100 ppmv
bypass; bypass duct and carbon monoxide). carbon monoxide).
stack \5,\ \6,\ \8\.

Destruction and removal For existing and new sources, 99.99% for each
principal organic hazardous constituent
efficiency ............ (POHC). For sources burning hazardous wastes
F020, F021, F022, F023, F026, or F027, how-
ever, 99.9999% for each POHC.

------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis. If
there is a separate alkali bypass stack, then both the alkali bypass
and main stack emissions must be less than the emission standard.
\2\ Mercury standard is an annual limit.
\3\ Standards are expressed as mass of pollutant stack emissions
attributable to the hazardous waste per million British thermal unit
heat input of the hazardous waste.
\4\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\5\ Sources that elect to comply with the carbon monoxide standard must
demonstrate compliance with the hydrocarbon standard during the
comprehensive performance test.
\6\ Hourly rolling average. Hydrocarbons reported as propane.

[[Page 21249]]

\7\ Applicable only to newly-constructed cement kilns at greenfield
sites (see 64 FR at 52885). The 50 ppmv standard is a 30-day block
average limit.
\8\ Measurement made in the bypass sampling system of any kiln (e.g.,
alkali bypass of a preheater/precalciner kiln; midkiln gas sampling
system of a long kiln).

A. What Are the Proposed Standards for Dioxin and Furan?

We are proposing to establish standards for existing and new cement
kilns that limit emissions of dioxin and furans to either 0.20 ng TEQ/
dscm or 0.40 ng TEQ/dscm and control of flue gas temperature not to
exceed 400[deg]F at the inlet to the particulate matter control device.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Dioxin and furan emissions for existing cement kilns are currently
limited by Sec. 63.1204(a)(1) to 0.20 ng TEQ/dscm or 0.40 ng TEQ/dscm
and control of flue gas temperature not to exceed 400[deg]F at the
inlet to the particulate matter control device. This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796, February
13, 2002).
Since promulgation of the 1999 final rule, we have obtained
additional dioxin/furan emissions data. We now have compliance test
emissions data for all but one cement kiln that burns hazardous waste.
The compliance test dioxin/furan emissions in our data base range from
approximately 0.004 to 20 ng TEQ/dscm.\91\ Cement kilns control dioxin
by quenching kiln gas temperatures so that gas temperatures at the
inlet to the particulate matter control device are below the range of
optimum dioxin/furan formation.
---------------------------------------------------------------------------

\91\ Even though all sources have recently demonstrated
compliance with the interim standards, the dioxin/furan data in our
data base preceded the compliance demonstration. This explains why
we have emissions data that are higher than the interim standard.
---------------------------------------------------------------------------

To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
Emissions Approach described in Part Two, Section VI.C above. The
calculated floor is 0.22 ng TEQ/dscm, which considers emissions
variability. These best performing sources controlled inlet
temperatures to the particulate matter control device from 380[deg]-
475[deg]F. Although some best performing sources had inlet temperatures
to the particulate matter control device within the optimum temperature
range (i.e., 400[deg]F) for formation of dioxin/furan, their
emissions were lower than other non-best performing sources. Our data
base shows that these other non-best performing sources, when operating
within a temperature range up to 475[deg]F, had emissions of dioxin/
furan as high as 1.2 ng TEQ/dscm. We cannot explain why some sources
emit dioxin/furan at significantly lower levels than other sources
operating at similar control device inlet temperatures. As noted
earlier, there are many uncertainties and imperfectly understood
complexities relating to dioxin/furan formation.
The data generally support the relationship between inlet
temperature to the particulate matter control device and dioxin/furan
emissions: When inlet temperatures are below the optimum range of
formation, dioxin/furan emissions are lower. However, the converse may
not hold: When inlet temperatures are within the optimum range of
formation, dioxin/furan emissions may or may not be higher (but in most
cases are higher). Moreover, we are concerned that a floor level of
0.22 ng TEQ/dscm is not replicable by all sources using temperature
control because we have emissions data from sources operating below the
optimum temperature range of dioxin/furan formation that is higher than
the calculated floor level of 0.22 ng TEQ/dscm. As a result of this
concern, we would identify the floor level as 0.22 ng TEQ/dscm or
controlling the inlet temperature to the particulate matter control device.
Allowing a source to comply with a temperature limit alone,
however, absent a numerical dioxin/furan emission limit, is less
stringent than the current interim standard of 0.20 ng TEQ/dscm, or
0.40 ng TEQ/dscm and control of flue gas temperature not to exceed
400[deg]F at the inlet to the particulate matter control device. The
current interim standard is a regulatory limit that is relevant in
identifying the floor level because it fixes a level of performance for
the source category. Given that all sources are achieving this interim
standard and that the interim standard is judged as more stringent than
the calculated MACT floor, the dioxin/furan floor level can be no less
stringent than the current regulatory limit. We are, therefore,
proposing the dioxin/furan floor level as 0.20 ng TEQ/dscm or 0.40 ng
TEQ/dscm and control of flue gas temperature not to exceed 400[deg]F at
the inlet to the particulate matter control device. This emission level
is being achieved by all sources because it is the current required
interim standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated activated carbon injection as beyond-the-floor control
for further reduction of dioxin/furan emissions. Activated carbon has
been demonstrated for controlling dioxin/furans in various combustion
applications. However, currently no cement kiln that burns hazardous
waste uses activated carbon injection. We evaluated a beyond-the-floor
level of 0.10 ng TEQ/dscm, which represents a 75% reduction in dioxin/
furan emissions from the floor level. We selected this level because it
represents a level that is considered routinely achievable with
activated carbon injection. In addition, we assumed for costing
purposes that cement kilns needing activated carbon injection to
achieve the beyond-the-floor level would install the activated carbon
injection system after the existing particulate matter control device
and add a new, smaller baghouse to remove the injected carbon with the
adsorbed dioxin/furan. We chose this costing approach to address
potential concerns that injected carbon may interfere with cement kiln
dust recycling practices.
The national incremental annualized compliance cost for cement
kilns to meet this beyond-the-floor level rather than comply with the
floor controls would be approximately $21 million and would provide an
incremental reduction in dioxin/furan emissions beyond the MACT floor
controls of 3.4 grams TEQ per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
impacts between activated carbon injection and controls likely to be
used to meet the floor level. We estimate that this beyond-the-floor
option would increase the amount of solid waste \92\ generated by 7,800
tons per year and would require sources to use an additional 2.6
million kW-hours per year beyond the requirements to achieve the floor
level. The costs associated with these impacts are accounted for in the
national annualized compliance cost estimates. Therefore, based on
these factors and costs of approximately $6.2 million per additional
gram of dioxin/furan removed, we are not proposing a

[[Page 21250]]

beyond-the-floor standard based on use of activated carbon injection.
---------------------------------------------------------------------------

\92\ Under the exemption from hazardous waste status in Sec.
261.4(b)(8), cement kiln dust is not currently classified as a
hazardous waste.
---------------------------------------------------------------------------

3. What Is the Rationale for the MACT Floor for New Sources?
Dioxin and furan emissions for new cement kilns are currently
limited by Sec. 63.1204(b)(1) to either 0.20 ng TEQ/dscm or 0.40 ng
TEQ/dscm and control of flue gas temperature not to exceed 400[deg]F at
the inlet to the particulate matter control device. This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796).
The calculated MACT floor for new sources would be 0.21 ng TEQ/
dscm, which considers emissions variability. This is an emission level
that the single best performing source identified by the Emissions
Approach could be expected to achieve in 99 of 100 future tests when
operating under conditions identical to the test conditions during
which the emissions data were obtained. As discussed for existing
sources, we are concerned that a floor level of 0.21 ng TEQ/dscm would
not be reproducible by all sources using temperature control because we
have emissions data from sources operating below the optimum
temperature range of dioxin/furan formation that is higher than the
calculated floor level of 0.21 ng TEQ/dscm. As a result of this
concern, we would identify the MACT floor as 0.21 ng TEQ/dscm or
controlling the inlet temperature to the particulate matter control device.
Allowing a source to comply with a temperature limit alone,
however, absent a numerical dioxin/furan emission limit, is less
stringent than the current interim standard of 0.20 ng TEQ/dscm, or
0.40 ng TEQ/dscm and control of flue gas temperature not to exceed
400[deg]F at the inlet to the particulate matter control device. The
current interim standard is a regulatory limit that is relevant in
identifying the floor level because it fixes a level of performance for
new cement kilns. Given that all sources are achieving this interim
standard and that the interim standard is judged as more stringent than
the calculated MACT floor, the dioxin/furan floor level can be no less
stringent than the current regulatory limit. We are, therefore,
proposing the dioxin/furan floor level as 0.20 ng TEQ/dscm or 0.40 ng
TEQ/dscm and control of flue gas temperature not to exceed 400[deg]F at
the inlet to the particulate matter control device.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated activated carbon injection as beyond-the-floor control
for further reduction of dioxin/furan emissions. We evaluated a beyond-
the-floor level of 0.10 ng TEQ/dscm, which represents a 75% reduction
in dioxin/furan emissions from the floor level. We selected this level
because it represents a level that is considered routinely achievable
with activated carbon injection. In addition, we assumed for costing
purposes that a new cement kiln will install the activated carbon
injection system after the existing particulate matter control device
and add a new, smaller baghouse to remove the injected carbon with the
adsorbed dioxin/furan. The incremental annualized compliance cost for a
new cement kiln to meet this beyond-the-floor level, rather than comply
with the floor level, would be approximately $1.0 million and would
provide an incremental reduction in dioxin/furan emissions of
approximately 0.17 grams TEQ per year, for a cost-effectiveness of $5.8
million per gram of dioxin/furan removed. Nonair quality health and
environmental impacts and energy effects were not significant factors.
For these reasons, we are not proposing a beyond-the-floor standard
based on activated carbon injection for new cement kilns. Therefore, we
are proposing the standard as 0.20 ng TEQ/dscm or 0.40 ng TEQ/dscm or
control of flue gas temperature not to exceed 400[deg]F at the inlet to
the particulate matter control device.

B. What Are the Proposed Standards for Mercury?

We are proposing to establish standards for existing and new cement
kilns that limit emissions of mercury to 64 and 35 [mu]g/dscm,
respectively. If we were to adopt these standards, then sources would
comply with the limit on an annual basis because the standards are
based on normal emissions data.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Mercury emissions for existing cement kilns are currently limited
to 120 [mu]g/dscm by Sec. 63.1204(a)(2).\93\ This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796). None of
the cement kilns burning hazardous waste use a dedicated control device
to remove mercury from the gas stream; however, kilns control the feed
concentration of mercury in the hazardous waste.
---------------------------------------------------------------------------

\93\ An alternative mercury standard is available for existing
cement kilns whereby a source can elect to comply with a hazardous
waste maximum theoretical emissions concentration or MTEC of mercury
of 120 [mu]g/dscm. MTEC is a term to compare metals and chlorine
feedrates across sources of different sizes. MTEC is defined as the
metals or chlorine feedrate divided by the gas flow rate and is
expressed in units of [mu]g/dscm.
---------------------------------------------------------------------------

We have emissions data for all sources. All of these data are best
classified as from normal operations, although, as explained below,
there is a substantial range within these data. For most sources, we
have normal emissions data from more than one test campaign. The normal
mercury stack emissions in our data base range from less than 2 to 118
[mu]g/dscm. These emissions are expressed as mass of mercury (from all
feedstocks) per unit volume of stack gas.
To identify the MACT floor, we evaluated all normal emissions data
using the SRE/Feed Approach. We considered normal emissions data from
all test campaigns.\94\ For example, one source in our data base has
normal emissions data for three different testing campaigns: 1992,
1995, and 1998. Under this approach we would consider the emissions
data from the three separate years or campaigns. We believe this
approach better captures the range of average emissions for a source
than only considering the most recent normal emissions. Given that no
cement kilns burning hazardous waste use a control device which
captures mercury from the flue gas stream, for purposes of this
analysis we assumed all sources achieved a SRE of zero. The effect of
this assumption is that the sources with the lowest mercury
concentrations in the hazardous waste were identified as the best
performing sources.
---------------------------------------------------------------------------

\94\ Given that we only have normal feedrate and emissions data
for mercury for cement kilns, we do not believe it is appropriate to
establish a hazardous waste thermal emissions-based standard. We
prefer to establish emission standards under the hazardous waste
thermal emissions format using compliance test data because the
metals feedrate information from compliance tests that we use to
apportion emissions to calculate emissions attributable to hazardous
waste are more reliable than feedrate data measured during testing
under normal, typical operations.
---------------------------------------------------------------------------

The calculated floor is 64 [mu]g/dscm, which considers emissions
variability, based on a hazardous waste maximum theoretical emissions
concentration (MTEC) of 26 [mu]g/dscm. This is an emission level that
the average of the best performing sources could be expected to achieve
in 99 of 100 future tests when operating under conditions identical to
the compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 59%
of sources and would reduce mercury emissions by 0.23 tons per year. If
we were to adopt such a floor level, we are proposing that sources
comply with the limit on an annual basis because it is based on normal
emissions data. Under this approach,

[[Page 21251]]

compliance would not be based on the use of a total mercury continuous
emissions monitoring system because these monitors have not been
adequately demonstrated as a reliable compliance assurance tool at
cement kiln sources. Instead, a source would maintain compliance with
the mercury standard by establishing and complying with short-term
limits on operating parameters for pollution control equipment and
annual limits on maximum total mercury feedrate in all feedstreams.
We did not use the stack emissions data of preheater/precalciner
kilns in the floor analysis because we believe the mercury emissions
are biased low when the in-line raw mill is on-line and biased high
when the in-line raw mill is off-line. (See earlier discussion on why
we are proposing not to subcategorize hazardous waste burning cement
kilns for mercury between wet process kilns and preheater/precalciner
kilns with in-line raw mills.) For either case, we believe the normal
mercury data are not representative of average emissions and,
therefore, not appropriate to include in the floor analysis. We request
comment on this data handling decision.
In the September 1999 final rule, we acknowledged that a cement
kiln using properly designed and operated MACT control technologies,
including controlling the levels of metals in the hazardous waste, may
not be capable of achieving a given emission standard because of
mineral and process raw material contributions that might cause an
exceedance of the emission standard. To address this concern, we
promulgated a provision that allows kilns to petition for alternative
standards provided they submit site-specific information that shows raw
material hazardous air pollutant contributions to the emissions prevent
the source from complying with the emission standard even though the
kiln is using MACT control. See Sec. 63.1206(b)(10).
Today's proposed floor of 64 [mu]g/dscm, which was based on a
hazardous waste MTEC of 26 [mu]g/dscm, may likewise necessitate such an
alternative because contributions of mercury in the raw materials and
fossil fuels at some sources may cause an exceedance of the emission
standard. The Agency intends to retain a source's ability to comply
with an alternative standard, and we request comment on two approaches
to accomplish this. The first approach would be to structure the
alternative standard similar to the petitioning process used under
Sec. 63.1206(b)(10). In the case of mercury for an existing cement
kiln, MACT would be defined as a hazardous waste feedrate corresponding
to an MTEC of 26 [mu]g/dscm. If we were to adopt this approach, we
would require sources, upon approval of the petition by the
Administrator, to comply with this hazardous waste MTEC on an annual
basis because it is based on normal emissions data. Under the second
approach, we would structure the alternative standard similar to the
framework used for the alternative interim standards for mercury under
Sec. 63.1206(b)(15). The operating requirement would be an annual MTEC
not to exceed 26 [mu]g/dscm. We also request comment on whether there
are other approaches that would more appropriately provide relief to
sources that cannot achieve a total stack gas concentration standard
because of emissions attributable to raw material and nonhazardous
waste fuels.
In June 2003, the Cement Kiln Recycling Coalition (CKRC) \95\
submitted to EPA information on actual mercury concentrations in the
hazardous waste burn tanks of all 14 cement facilities for a three year
period covering 1999 to 2001. In general, the information shows the
mercury concentration (in parts per million) in the hazardous waste for
each burn tank.\96\ In total, approximately 20,000 mercury burn tank
concentration data points are included in CKRC's submission.\97\ The
data show that approximately 50% of the individual burn tank
measurements are 0.6 ppmw or less, 75% are less than 1.1 ppmw, 88% are
less than 2 ppmw, and 97% of all burn tank measurements are less than 5
ppmw. For a hypothetical wet process cement kiln that gets 50% of its
required heat input from hazardous waste, a hazardous waste with a
mercury concentration of 0.6 ppmw equates approximately to an
uncontrolled (i.e., a system removal efficiency of zero) stack gas
concentration of 24 [mu]g/dscm. This estimated stack gas concentration,
of course, does not include contributions to emissions from other
mercury-containing feedstocks including raw materials and fossil fuels.
Mercury concentrations of 1.1, 2, and 5 ppmw in the hazardous waste
equate to uncontrolled stack gas concentrations of approximately 43,
79, and 196 [mu]g/dscm.\98\
---------------------------------------------------------------------------

\95\ Cement Kiln Recycling Coalition is a trade organization
that represents cement companies that burn hazardous wastes as a
fuel. CKRC also represents companies that manage and market
hazardous waste fuels used in cement kilns.
\96\ For two cement facilities, the mercury concentration data
are only available on a monthly-averaged basis.
\97\ Data from three of the facilities had a significant number
of individual measurements reported as not detectable and also had
relatively high analysis detection limits (compared to levels
achieved by other cement plants). The detection limit for most
cement kilns was typically 0.1 ppm or less. For purposes of today's
preamble discussion, the measurements from these three cement plants
are excluded from the data characterization conclusions.
\98\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 23.
---------------------------------------------------------------------------

We compared the concentration of mercury in the hazardous waste
associated with the normal emissions data in our data base to the 3-
year historical burn tank concentration data to estimate whether the
normal data in our data base--the basis of today's proposed floor of 64
[mu]g/dscm--are likely to represent the high end, low end, or close to
average emissions. Mercury feed concentration information is not
available for every test condition; however, the mercury concentrations
in the hazardous waste burned by the best performing sources during the
tests that generated the normal emissions ranged from 0.1 to 0.44 ppmw.
For the best performing sources comprising the MACT pool for which we
can make a comparison, it appears that the normal concentrations in the
hazardous waste during testing represent the low end (15th percentile
or less) of average mercury concentrations. We invite comment on
whether the normal emissions data in our data base are representative
of average emissions in practice and whether evaluating the data to
identify a floor level is appropriate.
In addition, we request comment on how to identify a floor level
using the 3-year hazardous waste mercury concentration data. One
potential approach would be to establish a hazardous waste feed
concentration standard expressed in ppmw. To identify a floor level
expressed as a hazardous waste feed concentration in ppmw, we
identified and evaluated the 3-year historical burn tank concentration
data of the five best performing facilities (those sources with the
lowest mean concentration considering variability). The calculated
alternative floor level is 2.2 ppmw in the hazardous waste. To put this
in context for a hypothetical wet process cement kiln that gets 50% of
its required heat input from hazardous waste, a mercury concentration
of 2.2 ppmw in the hazardous waste equates approximately to an
uncontrolled stack gas concentration of 86 [mu]g/dscm.\99\ This

[[Page 21252]]

estimated stack gas concentration, of course, does not include
contributions to emissions from other mercury-containing feedstocks
such as raw materials and fossil fuels. If we were to adopt such an
approach, we would require sources to comply with the feed
concentration standard on a short term basis (e.g., 12 hour average).
---------------------------------------------------------------------------

\99\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 23.
---------------------------------------------------------------------------

We also invite comment on whether we should judge an annual limit
of 64 [mu]g/dscm as less stringent than either the current emission
standard of 120 [mu]g/dscm or the hazardous waste MTEC of mercury of
120 [mu]g/dscm for cement kilns (so as to avoid any backsliding from a
current level of performance achieved by all sources, and hence, the
level of minimal stringency at which EPA could calculate the MACT
floor). In order to comply with the current emission standard,
generally a source must conduct manual stack sampling to demonstrate
compliance with the mercury emission standard and then establish a
maximum mercury feedrate limit based on operations during the
performance test. Following the performance test, the source complies
with a limit on the maximum total mercury feedrate in all feedstreams
on a 12-hour rolling average (not an annual average). Alternatively, a
source can elect to comply with a hazardous waste MTEC of mercury of
120 [mu]g/dscm that would require the source to limit the mercury
feedrate in the hazardous waste on a 12-hour rolling average. The floor
level of 64 [mu]g/dscm proposed today would allow a source to feed more
variable mercury-containing feedstreams (e.g., a hazardous waste with
an mercury MTEC greater than 120 [mu]g/dscm) than the current 12-hour
rolling average because today's proposed floor level is an annual
limit. For example, we estimated a hazardous waste MTEC for each burn
tank measurement associated with the 3-year historical concentration
data submitted by CKRC. We found that approximately 5% of burn tank
measurements would exceed a hazardous waste MTEC of 120 [mu]g/dscm,
including sources upon which the proposed floor is based.\100\
---------------------------------------------------------------------------

\100\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 23.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified three potential beyond-the-floor techniques for
control of mercury: (1) Activated carbon injection; (2) control of
mercury in the hazardous waste feed; and (3) control of mercury in the
raw materials and auxiliary fuels. For reasons discussed below, we are
not proposing a beyond-the-floor standard for mercury.
Use of Activated Carbon Injection. We evaluated activated carbon
injection as beyond-the-floor control for further reduction of mercury
emissions. Activated carbon has been demonstrated for controlling
mercury in several combustion applications; however, currently no
cement kiln that burns hazardous waste uses activated carbon injection.
Given this lack of experience using activated carbon injection, we made
a conservative assumption that the use of activated carbon injection
will provide 70% mercury control and evaluated a beyond-the-floor level
of 19 [mu]g/dscm. In addition, for costing purposes we assumed that
cement kilns needing activated carbon injection to achieve the beyond-
the-floor level would install the activated carbon injection system
after the existing particulate matter control device and add a new,
smaller baghouse to remove the injected carbon with the adsorbed
mercury. We chose this costing approach to address potential concerns
that injected carbon may interfere with cement kiln dust recycling
practices.
The national incremental annualized compliance cost for cement
kilns to meet this beyond-the-floor level rather than comply with the
floor controls would be approximately $16.8 million and would provide
an incremental reduction in mercury emissions beyond the MACT floor
controls of 0.41 tons per year. Nonair quality health and environmental
impacts and energy effects were evaluated to estimate the impacts
between activated carbon injection and controls likely to be used to
meet the floor level. We estimate that this beyond-the-floor option
would increase the amount of solid waste generated by 4,400 tons per
year and would require sources to use an additional 21 million kW-hours
per year beyond the requirements to achieve the floor level. The costs
associated with these impacts are accounted for in the national
annualized compliance cost estimates. Therefore, based on these factors
and costs of approximately $41 million per additional ton of mercury
removed, we are not proposing a beyond-the-floor standard based on
activated carbon injection.
Feed Control of Mercury in the Hazardous Waste. We also evaluated a
beyond-the-floor level of 51 [mu]g/dscm, which represents a 20%
reduction from the floor level. We chose a 20% reduction as a level
representing the practicable extent that additional feedrate control of
mercury in hazardous waste (beyond feedrate control that may be
necessary to achieve the floor level) can be used and still achieve
modest emissions reductions.\101\ The national incremental annualized
compliance cost for cement kilns to meet this beyond-the-floor level
rather than comply with the floor controls would be approximately $3.7
million and would provide an incremental reduction in mercury emissions
beyond the MACT floor controls of 180 pounds per year. Nonair quality
health and environmental impacts and energy effects were also
evaluated. Therefore, based on these factors and costs of approximately
$42 million per additional ton of mercury removed, we are not proposing
a beyond-the-floor standard based on feed control of mercury in the
hazardous waste.
---------------------------------------------------------------------------

\101\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume V: Emission Estimates and Engineering
Costs'', March 2004, Chapter 4.
---------------------------------------------------------------------------

Feed Control of Mercury in the Raw Materials and Auxiliary Fuels.
Cement kilns could achieve a reduction in mercury emissions by
substituting a raw material containing lower levels of mercury for a
primary raw material with a higher level. We believe that this beyond-
the-floor option would be even less cost-effective than either of the
options discussed above, however. Given that sources are sited near the
supply of the primary raw material, transporting large quantities of an
alternate source of raw materials is likely to be cost-prohibitive,
especially considering the small expected emissions reductions that
would result.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of mercury would be an appropriate
control option for sources. Given that most cement kilns burning
hazardous waste also burn coal as a fuel, we considered switching to
natural gas as a potential beyond-the-floor option. We are concerned
about the availability of natural gas to all cement kilns because
natural gas pipelines are not available in all regions of the United
States. See 68 FR 1673. Moreover, even where pipelines provide access
to natural gas, supplies of natural gas may not be adequate. For
example, it is common practice in cities during winter months (or
periods of peak demand) to prioritize natural gas usage for residential
areas before industrial usage. Requiring cement kilns to switch to
natural gas would place an even greater strain on natural gas
resources. Consequently, even where pipelines exist, some sources may
not be able to use natural gas during times of limited

[[Page 21253]]

supplies. Thus, natural gas may not be a viable control option for some
sources. Therefore, we are not proposing a beyond-the-floor standard
based on limiting mercury in the raw material feed and auxiliary fuels.
For the reasons discussed above, we propose not to adopt a beyond-
the-floor standard for mercury and propose to establish the emission
standard for existing cement kilns at 64 [mu]g/dscm. If we were to
adopt such a standard, we are proposing that sources comply with the
standard on an annual basis because it is based on normal emissions data.
3. What Is the Rationale for the MACT Floor for New Sources?
Mercury emissions from new cement kilns are currently limited to
120 [mu]g/dscm by Sec. 63.1204(b)(2). New cement kilns can comply with
an alternative mercury standard that limits the hazardous waste maximum
theoretical emissions concentration or MTEC of mercury of 120 [mu]g/
dscm. This standard was promulgated in the Interim Standards Rule (See
67 FR at 6796).
The MACT floor for new sources for mercury would be 35 [mu]g/dscm,
which considers emissions variability, based on a hazardous waste MTEC
of 5.1 [mu]g/dscm. This is an emission level that the single best
performing source identified with the SRE/Feed Approach could be
expected to achieve in 99 of 100 future tests when operating under
conditions identical to the test conditions during which the emissions
data were obtained. As for existing sources, we assumed all sources
equally achieved a SRE of zero. The effect of this assumption is that
the single source with the lowest mercury concentration in the
hazardous waste was identified as the best performing source. We also
invite comment on whether we should judge an annual limit of 35 [mu]g/
dscm as less stringent than either the current emission standard of 120
[mu]g/dscm or the hazardous waste MTEC of mercury of 120 [mu]g/dscm for
cement kilns (so as to avoid any backsliding from a current level of
performance achieved by all sources).
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified the same three potential beyond-the-floor techniques
for control of mercury: (1) Use of activated carbon; (2) control of
mercury in the hazardous waste feed; and (3) control of the mercury in
the raw materials and auxiliary fuels.
Use of Activated Carbon Injection. We evaluated activated carbon
injection as beyond-the-floor control for further reduction of mercury
emissions. We made a conservative assumption that the use of activated
carbon injection will provide 70% mercury control and evaluated a
beyond-the-floor level of 11 [mu]g/dscm. The incremental annualized
compliance cost for a new cement kiln to meet this beyond-the-floor
level, rather than comply with the floor level, would be approximately
$1.0 million and would provide an incremental reduction in mercury
emissions of approximately 88 pounds per year. We also estimate that
this option would increase the amount of solid waste generated by 400
tons per year and would require sources to use an additional 1.9
million kW-hours per year. Nonair quality health and environmental
impacts and energy effects are accounted for in the national annualized
compliance cost estimates. Therefore, based on these factors and costs
of $23 million per ton of mercury removed, we are not proposing a
beyond-the-floor standard based on activated carbon injection for new
cement kilns.
Feed Control of Mercury in the Hazardous Waste. We also believe
that the expense for further reduction in mercury emissions based on
further control of mercury concentrations in the hazardous waste is not
warranted. A beyond-the-floor level of 28 ug/dscm, which represents a
20% reduction from the floor level, would result in little additional
mercury reductions. For similar reasons discussed above for existing
sources, we conclude that a beyond-the-floor standard based on
controlling the mercury in the hazardous waste feed would not be
justified because of the costs coupled with estimated emission reductions.
Feed Control of Mercury in the Raw Materials and Auxiliary Fuels.
Cement kilns could achieve a reduction in mercury emissions by
substituting a raw material containing lower levels of mercury for a
primary raw material with a higher level. For a new source at an
existing cement plant, we believe that this beyond-the-floor option
would not be cost-effective due to the costs of transporting large
quantities of an alternate source of raw materials to the cement plant.
Given that the plant site already exists and sited near the source of
raw material, replacing the raw materials at the plant site with lower
mercury-containing materials would be the source's only option. For a
new cement kiln constructed at a new site--a greenfield site \102\--we
are not aware of any information and data from a source that has
undertaken or is currently located at a site whose raw materials are
low in mercury which would consistently decrease mercury emissions.
Further, we are uncertain as to what beyond-the-floor standard would be
achievable using a lower, if it exists, mercury-containing raw
material. Although we are doubtful that selecting a new plant site
based on the content of metals in the raw material is a realistic
beyond-the-floor option considering the numerous additional factors
that go into such a decision, we solicit comment on whether and what
level of a beyond-the-floor standard based on controlling the level of
mercury in the raw materials is appropriate.
---------------------------------------------------------------------------

\102\ A greenfield cement kiln is a kiln constructed at a site
where no cement kiln previously existed; however, a newly
constructed or reconstructed cement kiln at an existing site would
not be considered as a greenfield cement kiln.
---------------------------------------------------------------------------

We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of mercury would be an appropriate
control option for sources. We considered using natural gas in lieu of
a fossil fuel such as coal containing higher concentrations of mercury
as a potential beyond-the-floor option. As discussed for existing
sources, we are concerned about the availability of the natural gas
infrastructure in all regions of the United States and believe that
using natural gas would not be a viable control option for all new
sources. Therefore, we are not proposing a beyond-the-floor standard
based on limiting mercury in the raw material feed and auxiliary fuels.
Therefore, we propose a mercury standard of 35 ug/dscm for new
sources. If we were to adopt such a standard, we are proposing that
sources comply with the standard on an annual basis because it is based
on normal emissions data.

C. What Are the Proposed Standards for Particulate Matter?

We are proposing to establish standards for existing and new cement
kilns that limit emissions of particulate matter to 65 mg/dscm (0.028
gr/dscf) and 13 mg/dscm (0.0058 gr/dscf), respectively.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Particulate matter emissions for existing cement kilns are
currently limited to 0.15 kilograms of particulate matter per megagram
dry feed \103\ and 20% opacity by Sec. 63.1204(a)(7). This standard
was promulgated in the Interim Standards Rule (See 67 FR at

[[Page 21254]]

6796). The particulate matter standard is a surrogate control for the
metals antimony, cobalt, manganese, nickel, and selenium in the
hazardous waste and all HAP metals in the raw materials and auxiliary
fuels which are controllable by particulate matter control. All cement
kilns control particulate matter with baghouses and electrostatic
precipitators.
---------------------------------------------------------------------------

\103\ This standard equates approximately to a stack gas
concentration level of 0.030 gr/dscf for wet process kilns and 0.040
gr/dscf for preheater/precalciner kilns. The conversion varies by
process type because the amount of flue gas generated per ton of raw
material feed varies by process type.
---------------------------------------------------------------------------

We have compliance test emissions data for all cement kiln sources.
For most sources, we have compliance test emissions data from more than
one compliance test campaign. Our data base of particulate matter stack
emission concentrations range from 0.0008 to 0.063 gr/dscf.
To identify the floor level, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
Air Pollution Control Technology Approach. The calculated floor is 65
mg/dscm (0.028 gr/dscf), which considers emissions variability. This is
an emission level that the average of the best performing sources could
be expected to achieve in 99 of 100 future tests when operating under
conditions identical to the compliance test conditions during which the
emissions data were obtained. We estimate that this emission level is
being achieved by 44% of sources and would reduce particulate matter
emissions by 43 tons per year.
We are also proposing to delete the current opacity standard in
conjunction with revisions to the compliance assurance requirements for
particulate matter for cement kilns. These proposed compliance
assurance amendments include requiring a cement kiln source using a
baghouse to comply with the same bag leak detection system requirements
that are currently applicable to all other hazardous waste combustors
(see Sec. 63.1209(m)). A cement kiln source using an ESP has the
option either to (1) use a particulate matter emissions detector as a
process monitor in lieu of complying with operating parameter limits,
as we are proposing for all other hazardous waste combustor sources; or
(2) establish site-specific, enforceable operating parameter limits
that are linked to the automatic waste feed cutoff system. See Part
Three, Section III for a discussion of the proposed changes.
We also request comment on whether the particulate matter standard
should be expressed on a concentration basis (as proposed today) or on
a production-based format. A concentration-based standard is expressed
as mass of particulate matter per dry standard volume of gas (e.g., mg/
dscm as proposed today) while a production-based standard is expressed
as mass of particulate matter emitted per mass of dry raw material feed
to the kiln (e.g., the format of the interim standard). We evaluated
the compliance test production-based data associated with the most
recent test campaign to determine what the floor level would be under
this approach. The calculated floor would be 0.10 kilograms of
particulate matter per megagram dry feed. We note that a concentration
format can be viewed as penalizing more energy efficient kilns, which
burn less fuel and produce less kiln exhaust gas per megagram of dry
feed. This is because with a concentration-based standard the more
energy-efficient kilns would be restricted to a lower level of
particulate matter emitted per unit of production.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated improved particulate matter control to achieve a
beyond-the-floor standard of 32 mg/dscm (0.014 gr/dscf), which is a 50%
reduction from MACT floor emissions.\104\ For an existing source that
needs a significant reduction in particulate matter emissions, we
assumed and estimated costs for a new baghouse to achieve the beyond-
the-floor level. If little or modest emissions reductions were needed,
then improved control was costed as design, operation, and maintenance
modifications of the existing particulate matter control equipment.
---------------------------------------------------------------------------

\104\ We did not evaluate a beyond-the-floor standard based on
fuel substitution because particulate matter emissions from cement
kilns are primarily entrained raw material, not ash contributed by
the hazardous waste fuel. There is, therefore, no correlation
between particulate matter emissions and the level of ash in the
hazardous waste.
---------------------------------------------------------------------------

The national incremental annualized compliance cost for cement
kilns to meet this beyond-the-floor level rather than comply with the
floor controls would be approximately $4.8 million and would provide an
incremental reduction in particulate matter emissions beyond the MACT
floor controls of 385 tons per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
impacts between further improvements to control particulate matter and
controls likely to be used to meet the floor level. We estimate that
this beyond-the-floor option would increase the amount of solid waste
generated by 385 tons per year and would require sources to use an
additional 15 million kW-hours per year beyond the requirements to
achieve the floor level. The costs associated with these impacts are
accounted for in the national annualized compliance cost estimates.
Therefore, based on these factors and costs of approximately $12,400
per additional ton of particulate matter removed, we are not proposing
a beyond-the-floor standard based on improved particulate matter control.
3. What Is the Rationale for the MACT Floor for New Sources?
Particulate matter emissions from new cement kilns are currently
limited to 0.15 kilograms of particulate matter per megagram dry feed
and 20% opacity by Sec. 63.1204(b)(7). This standard was promulgated
in the Interim Standards Rule (See 67 FR at 6796).
The MACT floor for new sources for particulate matter would be 13
mg/dscm (0.0058 gr/dscf), which considers emissions variability. This
is an emission level that the single best performing source identified
with the Air Pollution Control Technology Approach could be expected to
achieve in 99 of 100 future tests when operating under operating
conditions identical to the test conditions during which the emissions
data were obtained. We are also proposing to delete the current opacity
standard in conjunction with revisions to the compliance assurance
requirements for particulate matter for cement kilns. See Part Three,
Section III for details.
As discussed for existing sources, we also request comment on
whether the particulate matter standard should be expressed on a
concentration basis or on a production-based format. We evaluated the
compliance test production-based data associated with the most recent
test campaign to determine what the floor level would be under this
approach. The calculated floor would be 0.028 kilograms of particulate
matter per megagram dry feed.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated improved emissions control based on a state-of-the-art
baghouse using a high quality fabric filter bag material to achieve a
beyond-the-floor standard of 6.7 mg/dscm (0.0029 gr/dscf). This
reduction represents a 50% reduction in particulate matter emissions
from MACT floor levels. The incremental annualized compliance cost for
a new cement kiln to meet this beyond-the-floor level, rather than
comply with the floor level, would be approximately $0.38 million and
would provide an incremental reduction in particulate matter emissions
of approximately 2.6 tons per year. We estimate that this

[[Page 21255]]

beyond-the-floor option would increase the amount of solid waste
generated by less than 6 tons per year and would require sources to use
an additional 1.8 million kW-hours per year beyond the requirements to
achieve the floor level. The costs associated with these impacts are
accounted for in the national annualized compliance cost estimates.
Therefore, based on these factors and costs of approximately $61,400
per additional ton of particulate matter removed, we are not proposing
a beyond-the-floor standard based on improved particulate matter
control for new cement kilns. Therefore, we propose a particulate
matter standard of 13 mg/dscm for new sources.

D. What Are the Proposed Standards for Semivolatile Metals?

We are proposing to establish standards for existing cement kilns
that limit emissions of semivolatile metals (cadmium and lead,
combined) to 4.0 x 10^-4 lbs semivolatile metals emissions
attributable to the hazardous waste per million Btu heat input of the
hazardous waste. The proposed standard for new sources is 6.2 x
10^-5 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Semivolatile metals emissions from existing cement kilns are
currently limited to 330 [mu]g/dscm by Sec. 63.1204(a)(3). This
standard was promulgated in the Interim Standards Rule (See 67 FR at
6796). Cement kilns control emissions of semivolatile metals with
baghouses or electrostatic precipitators and/or by controlling the feed
concentration of semivolatile metals in the hazardous waste.
We have compliance test emissions data for all cement kiln sources.
For most sources, we have compliance test emissions data from more than
one compliance test campaign. Semivolatile metal stack emissions range
from approximately 1 to 2,800 [mu]g/dscm. These emissions are expressed
as mass of semivolatile metals (from all feedstocks) per unit volume of
stack gas. Hazardous waste thermal emissions range from 3.0 x
10^-6 to 3.7 x 10^-3 lbs per million Btu. Hazardous
waste thermal emissions represent the mass of semivolatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste. Lead was the most significant contributor
to semivolatile emissions during compliance test conditions.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 4.0 x 10^-4 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which considers
emissions variability. This is an emission level that the average of
the best performing sources could be expected to achieve in 99 of 100
future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 81%
of sources and would reduce semivolatile metals emissions by 1 ton per year.
To put the proposed floor level in context for a hypothetical wet
process cement kiln that gets 50% of its required heat input from
hazardous waste, a thermal emissions level of 4.0 x 10^-4 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste equates approximately to
a stack gas concentration of 180 [mu]g/dscm. This estimated stack gas
concentration does not include contributions to emission from other
semivolatile metals-containing materials such as raw materials and
fossil fuels. The additional contribution to stack emissions of
semivolatile metals in an average raw material and coal is estimated to
range as high as 20 to 50 [mu]g/dscm. Thus, for the hypothetical wet
process cement kiln the thermal emissions floor level of 4.0 x
10^-4 lbs semivolatile metals attributable to the hazardous
waste per million Btu heat input of the hazardous waste is estimated to
be less than 230 [mu]g/dscm, which is less than the current interim
standard of 330 [mu]g/dscm. Given that comparing the proposed floor
level to the interim standard requires numerous assumptions (as just
illustrated) including hazardous waste fuel replacement rates, heat
input requirements per ton of clinker, concentrations of semivolatile
metals in the raw material and coal, and system removal efficiency, we
have a more detailed analysis in the background document.\105\ Our
detailed analysis indicates the proposed floor level is at least as
stringent as the interim standard (so as to avoid any backsliding from
a current level of performance achieved by all cement kilns, and hence,
the level of minimal stringency at which EPA could calculate the MACT
floor). Thus, we conclude that a dual standard--the semivolatile metals
standard as both the calculated floor level, expressed as a hazardous
waste thermal emissions level, and the current interim standard--is not
needed for this standard.
---------------------------------------------------------------------------

\105\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 23.
---------------------------------------------------------------------------

In the September 1999 final rule, we acknowledged that a cement
kiln using properly designed and operated MACT control technologies,
including controlling the levels of metals in the hazardous waste, may
not be capable of achieving a given emission standard because of
mineral and process raw material contributions that might cause an
exceedance of the emission standard. To address this concern, we
promulgated a provision that allows kilns to petition for alternative
standards provided that they submit site-specific information that
shows raw material hazardous air pollutant contributions to the
emissions prevent the source from complying with the emission standard
even though the kiln is using MACT control. See Sec. 63.1206(b)(10).
If we were to adopt the semivolatile (and low volatile) metals standard
using a thermal emissions format, then there would be no need for these
alternative standard provisions for semivolatile metals (since, as
explained earlier, that standard is based solely on semivolatile metals
contributions from hazardous waste fuels). Therefore, we would delete
the provisions of Sec. 63.1206(b)(10) as they apply to semivolatile
(and low volatile) metals. We invite comment on this approach.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified three potential beyond-the-floor techniques for
control of semivolatile metals: (1) Improved particulate matter
control; (2) control of semivolatile metals in the hazardous waste
feed; and (3) control of the semivolatile metals in the raw materials
and fuels. For reasons discussed below, we are not proposing a beyond-
the-floor standard for semivolatile metals.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of semivolatile metals. Our data show that all
cement kilns are already achieving greater than 98.6% system removal
efficiency for semivolatile metals, with most attaining 99.9% removal.
Thus, additional controls of particulate matter are likely to result in
only modest additional reductions of semivolatile metals emissions. We
evaluated a beyond-the-floor level of 2.0 x 10^-4 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which

[[Page 21256]]

represents a 50% reduction in emissions from MACT floor levels. The
national incremental annualized compliance cost for cement kilns to
meet this beyond-the-floor level rather than comply with the floor
controls would be approximately $2.7 million and would provide an
incremental reduction in semivolatile metals emissions beyond the MACT
floor controls of 1.2 tons per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
impacts between further improvements to control particulate matter and
controls likely to be used to meet the floor level. We estimate that
this beyond-the-floor option would increase the amount of solid waste
generated by 300 tons per year and would also require sources to use an
additional 5.7 million kW-hours of energy per year to achieve the floor
level. The costs associated with these impacts are accounted for in the
national annualized compliance cost estimates. Therefore, based on
these factors and costs of approximately $2.3 million per additional
ton of semivolatile metals removed, we are not proposing a beyond-the-
floor standard based on improved particulate matter control.
Feed Control of Semivolatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 3.2 x 10^-4 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which represents a 20%
reduction from the floor level. We chose a 20% reduction as a level
representing the practicable extent that additional feedrate control of
semivolatile metals in hazardous waste can be used and still achieve
appreciable emissions reductions. The national incremental annualized
compliance cost for cement kilns to meet this beyond-the-floor level
rather than comply with the floor controls would be approximately $0.30
million and would provide an incremental reduction in semivolatile
metals emissions beyond the MACT floor controls of 0.36 tons per year.
Nonair quality health and environmental impacts and energy effects were
evaluated and are included in the national compliance cost estimates.
Therefore, based on these factors and costs of approximately $0.84
million per additional ton of semivolatile metals removed, we are not
proposing a beyond-the-floor standard based on feed control of
semivolatile metals in the hazardous waste.
Feed Control of Semivolatile Metals in the Raw Materials and
Auxiliary Fuels. Cement kilns could achieve a reduction in semivolatile
metal emissions by substituting a raw material containing lower levels
of lead and/or cadmium for a primary raw material with higher levels of
these metals. We believe that this beyond-the-floor option would even
be less cost-effective than either of the options discussed above,
however. Given that cement kilns are sited near the primary raw
material supply, acquiring and transporting large quantities of an
alternate source of raw materials is likely to be cost-prohibitive.
Therefore, we are not proposing a beyond-the-floor standard based on
limiting semivolatile metals in the raw material feed. We also
considered whether fuel switching to an auxiliary fuel containing a
lower concentration of semivolatile metals would be an appropriate
control option for sources. Given that most cement kilns burning
hazardous waste also burn coal as a fuel, we considered switching to
natural gas as a potential beyond-the-floor option. For the same
reasons discussed for mercury, we judge a beyond-the-floor standard
based on fuel switching as unwarranted.
For the reasons discussed above, we propose to establish the
emission standard for existing cement kilns at 4.0 x 10^-4
lbs semivolatile metals emissions attributable to the hazardous waste
per million Btu heat input of the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
Semivolatile metals emissions from new cement kilns are currently
limited to 180 [mu]g/dscm by Sec. 63.1204(b)(3). This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796).
The MACT floor for new sources for semivolatile metals would be 6.2
x 10^-5 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste,
which considers emissions variability. This is an emission level that
the single best performing source identified with the SRE/Feed Approach
could be expected to achieve in 99 of 100 future tests when operating
under conditions identical to the test conditions during which the
emissions data were obtained.
To put the proposed floor level in context for a hypothetical wet
process cement kiln that gets 50% of its required heat input from
hazardous waste, a thermal emissions level of 6.2 x 10^-5 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste equates approximately to
a stack gas concentration of 80 [mu]g/dscm, including contributions
from typical raw materials and coal. Thus, for the hypothetical wet
process cement kiln the thermal emissions floor level of 6.2 x
10^-5 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste is
estimated to be less than the current interim standard for new sources
of 180 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified the same three potential beyond-the-floor techniques
for control of semivolatile metals: (1) Improved control of particulate
matter; (2) control of semivolatile metals in the hazardous waste feed;
and (3) control of semivolatile metals in the raw materials and fuels.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of semivolatile metals. We evaluated improved
control of particulate matter based on a state-of-the-art baghouse
using a high quality fabric filter bag material as beyond-the-floor
control for further reductions in semivolatile metals emissions. We
evaluated a beyond-the-floor level of 2.5 x 10^-5 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste. The incremental
annualized compliance cost for a new cement kiln with an average gas
flow rate to meet this beyond-the-floor level, rather than to comply
with the floor level, would be approximately $0.38 million and would
provide an incremental reduction in semivolatile metals emissions of
approximately 144 pounds per year. Nonair quality health and
environmental impacts and energy effects were evaluated and are
included in the cost estimates. For these reasons and costs of $5.3
million per ton of semivolatile metals removed, we are not proposing a
beyond-the-floor standard based on improved particulate matter control
for new cement kilns.
Feed Control of Semivolatile Metals in the Hazardous Waste. We also
believe that the expense for further reduction in semivolatile metals
emissions based on further control of semivolatile metals
concentrations in the hazardous waste is not warranted. We also
evaluated a beyond-the-floor level of 5.0 x 10^-5 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which represents a 20%
reduction from the floor level. Nonair quality health and environmental
impacts and energy effects were evaluated and are included in the
compliance cost estimates. For similar

[[Page 21257]]

reasons discussed above for existing sources, we conclude that a
beyond-the-floor standard based on controlling the concentration of
semivolatile metals levels in the hazardous waste feed would not be
justified because of the costs coupled with estimated emission
reductions.
Feed Control of Semivolatile Metals in the Raw Materials and
Auxiliary Fuels. Cement kilns could achieve a reduction in semivolatile
metals emissions by substituting a raw material containing lower levels
of cadmium and lead for a primary raw material with a higher level. For
a new source at an existing cement plant, we believe that this beyond-
the-floor option would not be cost-effective due to the costs of
transporting large quantities of an alternate source of raw materials
to the cement plant. Given that the plant site already exists and sited
near the source of raw material, replacing the raw materials at the
plant site with lower semivolatile metals-containing materials would be
the source's only option. For a cement kiln constructed at a new
greenfield site, we are not aware of any information and data from a
source that has undertaken or is currently located at a site whose raw
materials are inherently lower in semivolatile metals that would
consistently achieve reduced semivolatile metals emissions. Further, we
are uncertain as to what beyond-the-floor standard would be achievable
using a lower, if it exists, semivolatile metals-containing raw
material. Although we are doubtful that selecting a new plant site
based on the content of metals in the raw material is a realistic
beyond-the-floor option considering the numerous additional factors
that go into such a decision, we solicit comment on whether and what
level of a beyond-the-floor standard based on controlling the level of
semivolatile metals in the raw materials is appropriate.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of semivolatile metals would be an
appropriate control option for sources. Given that most cement kilns
burning hazardous waste also burn coal as a fuel, we considered
switching to natural gas as a potential beyond-the-floor option. For
the same reasons discussed for mercury, we judge a beyond-the-floor
standard based on fuel switching as unwarranted.
For the reasons discussed above, we propose to establish the
emission standard for new cement kilns at 6.2 x 10^-5 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste.

E. What Are the Proposed Standards for Low Volatile Metals?

We are proposing to establish standards for existing and new cement
kilns that limit emissions of low volatile metals (arsenic, beryllium,
and chromium, combined) to 1.4 x 10^-5 lbs low volatile
metals emissions attributable to the hazardous waste per million Btu
heat input of the hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Low volatile metals emissions from existing cement kilns are
currently limited to 56 [mu]g/dscm by Sec. 63.1204(a)(4). This
standard was promulgated in the Interim Standards Rule (see 67 FR at
6796). Cement kilns control emissions of low volatile metals with
baghouses or electrostatic precipitators and/or by controlling the feed
concentration of low volatile metals in the hazardous waste.
We have compliance test emissions data for all cement kiln sources.
For most sources, we have compliance test emissions data from more than
one compliance test campaign. Low volatile metal stack emissions range
from approximately 1 to 100 [mu]g/dscm. These emissions are expressed
as mass of low volatile metals (from all feedstocks) per unit volume of
stack gas. Hazardous waste thermal emissions range from 9.2 x
10^-7 to 1.0 x 10^-5 lbs per million Btu. Hazardous
waste thermal emissions represent the mass of low volatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste. For nearly every cement kiln, chromium
was the most significant contributor to low volatile emissions.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 1.4 x 10^-5 lbs
low volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which considers
emissions variability. This is an emission level that the average of
the best performing sources could be expected to achieve in 99 of 100
future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 52%
of sources and would reduce low volatile metals emissions by 0.10 tons
per year.
To put the proposed floor level in context for a hypothetical wet
process cement kiln that gets 50% of its required heat input from
hazardous waste, a thermal emissions level of 1.4 x 10^-5 lbs
low volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste equates approximately to
a stack gas concentration of 7 [mu]g/dscm. This estimated stack gas
concentration does not include contributions to emission from other low
volatile metals-containing materials such as raw materials and fossil
fuels. The additional contribution to stack emissions of low volatile
metals in an average raw material and coal is estimated to range from
less than 1 to 15 [mu]g/dscm. Thus, for the hypothetical wet process
cement kiln the thermal emissions floor level of 1.4 x 10^-5
lbs low volatile metals attributable to the hazardous waste per million
Btu heat input of the hazardous waste is estimated to be less than 22
[mu]g/dscm, which is less than the current interim standard of 56
[mu]g/dscm. Given that comparing the proposed floor level to the
interim standard requires numerous assumptions (as just illustrated)
including hazardous waste fuel replacement rates, heat input
requirements per ton of clinker, concentrations of low volatile metals
in the raw material and coal, and system removal efficiency, we have
included a more detailed analysis in the background document.\106\ Our
detailed analysis indicates the proposed floor level is as least as
stringent as the interim standard (so as to avoid any backsliding from
a current level of performance achieved by all cement kilns, and hence,
the level of minimal stringency at which EPA could calculate the MACT
floor). Thus, we conclude that a dual standard--the low volatile metals
standard as both the calculated floor level, expressed as a hazardous
waste thermal emissions level, and the current interim standard--is not
needed for this standard.
---------------------------------------------------------------------------

\106\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 23.
---------------------------------------------------------------------------

[[Page 21258]]

Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of low volatile metals. Our data show that all
cement kilns are already achieving greater than 99.9% system removal
efficiency for low volatile metals, with most attaining 99.99% removal.
Thus, additional control of particulate matter emissions is likely to
result in only a small increment in reduction of low volatile metals
emissions. We evaluated a beyond-the-floor level of 7.0 x
10^-6 lbs low volatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste,
which represents a 50% reduction in emissions from MACT floor levels.
The national incremental annualized compliance cost for cement kilns to
meet this beyond-the-floor level rather than comply with the floor
controls would be approximately $3.7 million and would provide an
incremental reduction in low volatile metals emissions beyond the MACT
floor controls of 120 pounds per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
impacts between further improvements to control particulate matter and
controls likely to be used to meet the floor level. We estimate that
this beyond-the-floor option would increase the amount of solid waste
generated by 72 tons per year and would also require sources to use an
additional 1.2 million kW-hours per year beyond the requirements to
achieve the floor level. The costs associated with these impacts are
accounted for in the national annualized compliance cost estimates.
Therefore, based on these factors and costs of approximately $63
million per additional ton of low volatile metals removed, we are not
proposing a beyond-the-floor standard based on improved particulate
matter control.
Feed Control of Low Volatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 1.1 x 10^-5 lbs low
volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which represents a 20%
reduction from the floor level. We chose a 20% reduction as a level
representing the practicable extent that additional feedrate control of
mercury in hazardous waste can be used and still achieve appreciable
emissions reductions. The national incremental annualized compliance
cost for cement kilns to meet this beyond-the-floor level rather than
comply with the floor controls would be approximately $1.2 million and
would provide an incremental reduction in low volatile metals emissions
beyond the MACT floor controls of 38 pounds per year. Nonair quality
health and environmental impacts and energy effects were evaluated and
are included in the cost estimates. Therefore, based on these factors
and costs of approximately $64 million per additional ton of low
volatile metals removed, we are not proposing a beyond-the-floor
standard based on feed control of low volatile metals in the hazardous
waste.
Feed Control of Low Volatile Metals in the Raw Materials and
Auxiliary Fuels. Cement kilns could achieve a reduction in low volatile
metal emissions by substituting a raw material containing lower levels
of arsenic, beryllium, and/or chromium for a primary raw material with
higher levels of these metals. We believe that this beyond-the-floor
option would even be less cost-effective than either of the options
discussed above, however. Given that cement kilns are sited near the
primary raw material supply, acquiring and transporting large
quantities of an alternate source of raw materials is likely to be
cost-prohibitive. Therefore, we are not proposing a beyond-the-floor
standard based on limiting low volatile metals in the raw material
feed. We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of low volatile metals would be an
appropriate control option for sources. Given that most cement kilns
burning hazardous waste also burn coal as a fuel, we considered
switching to natural gas as a potential beyond-the-floor option. For
the same reasons discussed for mercury, we judge a beyond-the-floor
standard based on fuel switching as unwarranted.
For the reasons discussed above, we propose to establish the
emission standard for existing cement kilns at 1.4 x 10^-5
lbs low volatile metals emissions attributable to the hazardous waste
per million Btu heat input of the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
Low volatile metals emissions from new cement kilns are currently
limited to 54 [mu]g/dscm by Sec. 63.1204(b)(4). This standard was
promulgated in the Interim Standards Rule (see 67 FR at 6796, February
13, 2002).
The floor level for new sources for low volatile metals would be
1.4 x 10^-5 lbs low volatile metals emissions attributable to
the hazardous waste per million Btu heat input of the hazardous waste,
which considers emissions variability. This is an emission level that
the single best performing source identified with the SRE/Feed Approach
could be expected to achieve in 99 of 100 future tests when operating
under conditions identical to the test conditions during which the
emissions data were obtained.
To put the proposed floor level in context for a hypothetical wet
process cement kiln that gets 50% of its required heat input from
hazardous waste, a thermal emissions level of 1.4 x 10^-5 lbs
low volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste equates approximately to
a stack gas concentration of 22 [mu]g/dscm, including contributions
from typical raw materials and coal. Thus, for the hypothetical wet
process cement kiln the thermal emissions floor level of 6.2 x
10^-\5\ lbs low volatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste is
estimated to be more stringent than the current interim standard for
new sources of 54 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified the same three potential beyond-the-floor techniques
for control of low volatile metals: (1) Improved control of particulate
matter; (2) control of low volatile metals in the hazardous waste feed;
and (3) control of low volatile metals in the raw materials and fuels.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of low volatile metals. We evaluated improved
control of particulate matter based on a state-of-the-art baghouse
using a high quality fabric filter bag material as beyond-the-floor
control for further reductions in low volatile metals emissions. We
evaluated a beyond-the-floor level of 6.0 x 10^-6 lbs low
volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste. The incremental
annualized compliance cost for a new cement kiln to meet this beyond-
the-floor level, rather than comply with the floor level, would be
approximately $0.38 million and would provide an incremental reduction
in low volatile metals emissions of approximately 33 pounds per year.
Nonair quality health and environmental impacts and energy effects were
evaluated and are included in the cost estimates. For these reasons and
costs of $23.5 million per ton of low volatile metals removed, we are
not proposing a beyond-the-floor standard based on improved particulate
matter control for new cement kilns.

[[Page 21259]]

Feed Control of Low Volatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 1.1 x 10^-5 lbs low
volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which represents a 20%
reduction from the floor level. We believe that the expense for further
reduction in low volatile metals emissions based on further control of
low volatile metals concentrations in the hazardous waste is not
warranted given the costs, nonair quality health and environmental
impacts, and energy effects.
Feed Control of Low Volatile Metals in the Raw Materials and
Auxiliary Fuels. Cement kilns could achieve a reduction in low volatile
metals emissions by substituting a raw material containing lower levels
of low volatile metals for a primary raw material with a higher level.
For a new source at an existing cement plant, we believe that this
beyond-the-floor option would not be cost-effective due to the costs of
transporting large quantities of an alternate source of raw materials
to the cement plant. Given that the plant site already exists and sited
near the source of raw material, replacing the raw materials at the
plant site with lower low volatile metals-containing materials would be
the source's only option. For a cement kiln constructed at a new
greenfield site, we are not aware of any information and data from a
source that has undertaken or is currently located at a site whose raw
materials are inherently lower in low volatile metals that would
consistently achieve reduced low volatile metals emissions. Further, we
are uncertain as to what beyond-the-floor standard would be achievable
using a lower, if it exists, low volatile metals-containing raw
material. Although we are doubtful that selecting a new plant site
based on the content of metals in the raw material is a realistic
beyond-the-floor option considering the numerous additional factors
that go into such a decision, we solicit comment on whether and what
level of a beyond-the-floor standard based on controlling the level of
low volatile metals in the raw materials is appropriate.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of low volatile metals would be an
appropriate control option for sources. Given that most cement kilns
burning hazardous waste also burn coal as a fuel, we considered
switching to natural gas as a potential beyond-the-floor option. For
the same reasons discussed for mercury, we judge a beyond-the-floor
standard based on fuel switching as unwarranted.
Therefore, we are proposing a low volatile metals standard of 1.4 x
10^-5 lbs low volatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste.

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?

We are proposing to establish standards for existing and new cement
kilns that limit total chlorine emissions (hydrogen chloride and
chlorine gas, combined, reported as a chloride equivalent) to 110 and
83 ppmv, respectively. However, we are also proposing to establish
alternative risk-based standards, pursuant to CAA section 112(d)(4),
which could be elected by the source in lieu of the MACT emission
standards for total chlorine. The emission limits would be based on
national exposure standards that ensure protection of public health
with an ample margin of safety. See Part Two, Section XIII for
additional details.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Total chlorine emissions from existing cement kilns are limited to
130 ppmv by Sec. 63.1204(a)(6). This standard was promulgated in the
Interim Standards Rule (See 67 FR at 6796). None of the cement kilns
burning hazardous waste use a dedicated control device, such as a wet
scrubber, to remove total chlorine from the gas stream. However, the
natural alkalinity in some of the raw materials is highly effective at
removing chlorine from the gas stream. Our data base shows that the
majority of the system removal efficiency (SRE) data of total
chlorine--over 80%--indicate a SRE greater than 95%. This scrubbing
effect, though quite effective, varies across different sources and
also at individual sources over time due to differences in raw
materials, operating conditions, cement kiln dust recycle rates, and
production requirements. Likewise, our data show that total chlorine
emissions from a given source can vary over a considerable range. Based
on these data, we conclude that the best (highest) SRE achieved at a
given source is not duplicable or replicable.
The majority of the chlorine fed to the cement kiln during a
compliance test comes from the hazardous waste.\107\ In all but a few
cases the hazardous waste contribution to the total amount of chlorine
fed to the kiln represented at least 75% of the total chlorine loading
to the kiln. As we identified in the September 1999 final rule, the
proposed MACT floor control for total chlorine is based on controlling
the concentration of chlorine in the hazardous waste. The chlorine
concentration in the hazardous waste will affect emissions of total
chlorine at a given SRE because emissions increase as the chlorine
loading increases.
---------------------------------------------------------------------------

\107\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards'',
March 2004, Chapter 2.
---------------------------------------------------------------------------

We have compliance test emissions data for all cement kiln sources.
For most sources, we have compliance test emissions data from more than
one compliance test campaign. Total chlorine emissions range from less
than 1 ppmv to 192 ppmv.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using a
variant of the SRE/Feed Approach because of concerns about a cement
kiln's ability to replicate a given SRE. To identify the floor level we
first evaluated the chlorine feed level in the hazardous waste for all
sources. The best performing sources had the lowest maximum theoretical
emissions concentration or MTEC, considering variability. We then
applied a SRE of 90% to the best performing sources' total MTEC (i.e.,
includes chlorine contributions to emissions from all feedstreams such
as raw material and fossil fuels) to identify the floor level. Given
our concerns about the reproducibility of SREs of total chlorine, we
selected a SRE of 90% because our data base shows that all sources have
demonstrated this SRE at least once (and often several times) during a
compliance test. The calculated floor is 110 ppmv, which considers
emissions variability. This is an emission level that the best
performing feed control sources could be expected to achieve in 99 of
100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 93%
of sources and would reduce total chlorine emissions by 64 tons per year.
We also invite comment on an alternative approach to establish a
floor level expressed as a hazardous waste thermal feed
concentration.\108\ A hazardous waste thermal feed concentration is
expressed as mass of chlorine in the hazardous waste per

[[Page 21260]]

million Btu heat input contributed by the hazardous waste. The floor
would be based on the best five performing sources with the lowest
thermal feed concentration of chlorine in the hazardous waste
considering each source's most recent compliance test data. One
advantage of this approach is that the uncertainty surrounding the
capture (SRE) of chlorine in a kiln is removed. The calculated floor
level would be 2.4 lbs chlorine in the hazardous waste per million Btu
in the hazardous waste, which considers variability. For a hypothetical
wet process cement kiln that gets 50% of its required heat input from
hazardous waste, a hazardous waste with a chlorine concentration of 2.4
lbs chlorine per million Btu and achieving 90% SRE equates
approximately to a stack gas concentration of 75 ppmv. This estimated
stack gas concentration does not include contributions to emission from
other chlorine-containing materials such as raw materials and fossil
fuels. The additional contribution to stack emissions of total chlorine
in an average raw material and coal is estimated to range from less
than 1 to 35 ppmv. Thus, for the hypothetical wet process cement kiln
this floor level is estimated to be less than 110 ppmv, which is less
than the current interim standard of 130 ppmv.
---------------------------------------------------------------------------

\108\ We are also requesting comment on whether the hazardous
waste feed concentration floor level should be the standard itself
(i.e., no stack emission concentration standard) or as an
alternative to the stack emission standard (e.g., sources have the
opinion to comply with either the calculated stack emissions
concentration or the hazardous waste feed concentration limit).
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified three potential beyond-the-floor techniques for
control of total chlorine: (1) Use of wet scrubbers; (2) control of
chlorine in the hazardous waste feed; and (3) control of the chlorine
in the raw materials. For reasons discussed below, we are not proposing
a beyond-the-floor standard for total chlorine.
Use of Wet Scrubbers. We evaluated the use of wet scrubbers as
beyond-the-floor control for further reduction of mercury emissions.
Wet scrubbers are not currently being used at any hazardous waste
burning cement kilns to capture hydrogen chloride. We evaluated a
beyond-the-floor level of 55 ppmv. The national incremental annualized
compliance cost for cement kilns to meet this beyond-the-floor level
rather than comply with the floor controls would be approximately $3.4
million and would provide an incremental reduction in total chlorine
emissions beyond the MACT floor controls of 370 tons per year. Nonair
quality health and environmental impacts and energy effects were
evaluated to estimate the impacts between wet scrubbing and controls
likely to be used to meet the floor level. We estimate that this
beyond-the-floor option would increase the amount of water usage and
waste water generated by 1.5 billion gallon per year. The option would
also require sources to use an additional 12 million kW-hours per year
beyond the requirements to achieve the floor level. The costs
associated with these impacts are accounted for in the national
annualized compliance cost estimates. Therefore, based on these factors
and costs of approximately $9,300 per additional ton of total chlorine
removed, we are not proposing a beyond-the-floor standard based on wet
scrubbing.
Feed Control of Chlorine in the Hazardous Waste. We also evaluated
a beyond-the-floor level of 88 ppmv, which represents a 20% reduction
from the floor level. We chose a 20% reduction as a level that
represents the practicable extent that additional feedrate control of
chlorine in the hazardous waste can be used and still achieve modest
emissions reductions. The national incremental annualized compliance
cost for cement kilns to meet this beyond-the-floor level rather than
comply with the floor controls would be approximately $1.1 million and
would provide an incremental reduction in total chlorine emissions
beyond the MACT floor controls of 100 tons per year. Nonair quality
health and environmental impacts and energy effects were also evaluated
and are included in the compliance cost estimates. Therefore, based on
these factors and costs of approximately $11,000 per additional ton of
total chlorine, we are not proposing a beyond-the-floor standard based
on feed control of chlorine in the hazardous waste.
Feed Control of Chlorine in the Raw Materials and Auxiliary Fuels.
Cement kilns could achieve a reduction in total chlorine emissions by
substituting a raw material containing lower levels of chlorine for a
primary raw material with higher levels of chlorine. We believe that
this beyond-the-floor option would even be less cost-effective than
either of the options discussed above because most chlorine feed to the
kiln is in the hazardous waste. In addition, given that cement kilns
are sited near the primary raw material supply, acquiring and
transporting large quantities of an alternate source of raw materials
is likely to be cost-prohibitive. Therefore, we are not proposing a
beyond-the-floor standard based on limiting chlorine in the raw
material feed. We also considered whether fuel switching to an
auxiliary fuel containing a lower concentration of chlorine would be an
appropriate control option for kilns. Given that most cement kilns
burning hazardous waste also burn coal as a fuel, we considered
switching to natural gas as a potential beyond-the-floor option. For
the same reasons discussed for mercury, we judge a beyond-the-floor
standard based on fuel switching as unwarranted.
For the reasons discussed above, we propose not to adopt a beyond-
the-floor standard for total chlorine and propose to establish the
emission standard for existing cement kilns at 110 ppmv.
3. What Is the Rationale for the MACT Floor for New Sources?
Total chlorine emissions from new cement kilns are currently
limited to 86 ppmv by Sec. 63.1204(b)(6). This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6796). The MACT
floor for new sources for total chlorine would be 78 ppmv, which
considers emissions variability. This is an emission level that the
single best performing source identified with the SRE/Feed Approach
could be expected to achieve in 99 of 100 future tests when operating
under conditions identical to the test conditions during which the
emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified similar potential beyond-the-floor techniques for
control of total chlorine for new sources: (1) Use of wet scrubbing;
(2) control of chlorine in the hazardous waste feed; and (3) control of
chlorine in the raw materials and fuels.
Use of Wet Scrubbers. We considered wet scrubbing as beyond-the-
floor control for further reductions in total chlorine emissions and
evaluated a beyond-the-floor level of 39 ppmv. The incremental
annualized compliance cost for a new cement kiln to meet this beyond-
the-floor level, rather than comply with the floor level, would be
approximately $1.2 million and would provide an incremental reduction
in total chlorine emissions of approximately 22 tons per year. Nonair
quality health and environmental impacts and energy effects were
evaluated and are included in the cost estimates. For these reasons and
costs of $24,000 per ton of total chlorine removed, we are not
proposing a beyond-the-floor standard based on wet scrubbing for new
cement kilns.
Feed Control of Low Volatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 62 ppmv, which represents a 20%
reduction from the floor level. We believe that the expense for further
reduction in total chlorine emissions

[[Page 21261]]

based on further control of chlorine concentrations in the hazardous
waste is not warranted given the costs, nonair quality health and
environmental impacts, and energy effects.
Feed Control of Chlorine in the Raw Materials and Auxiliary Fuels.
Cement kilns could achieve a reduction in total chlorine emissions by
substituting a raw material containing lower levels of chlorine for a
primary raw material with a higher level. For a new source at an
existing cement plant, we believe that this beyond-the-floor option
would not be cost-effective due to the costs of transporting large
quantities of an alternate source of raw materials to the cement plant.
Given that the plant site already exists and sited near the source of
raw material, replacing the raw materials at the plant site with lower
chlorine-containing materials would be the source's only option. For a
cement kiln constructed at a new greenfield site, we are not aware of
any information and data from a source that has undertaken or is
currently located at a site whose raw materials are inherently lower in
chlorine that would consistently achieve reduced total chlorine
emissions. Further, we are uncertain as to what beyond-the-floor
standard would be achievable using a lower, if it exists, chlorine-
containing raw material. Although we are doubtful that selecting a new
plant site based on the content of chlorine in the raw material is a
realistic beyond-the-floor option considering the numerous additional
factors that go into such a decision, we solicit comment on whether and
what level of a beyond-the-floor standard based on controlling the
level of chlorine in the raw materials is appropriate.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of chlorine would be an appropriate
control option for sources. Given that most cement kilns burning
hazardous waste also burn coal as a fuel, we considered switching to
natural gas as a potential beyond-the-floor option. For the same
reasons discussed for mercury, we judge a beyond-the-floor standard
based on fuel switching as unwarranted.
Therefore, we are proposing a total chlorine standard of 78 ppmv
for new cement kilns.

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

Hydrocarbon and carbon monoxide standards are surrogates to control
emissions of organic hazardous air pollutants for existing and new
cement kilns. For cement kilns without bypass or midkiln sampling
systems, the standard for existing sources limit hydrocarbon or carbon
monoxide concentrations to 20 ppmv or 100 ppmv, respectively. The
standards for new sources limit (1) hydrocarbons to 20 ppmv; or (2)
carbon monoxide to 100 ppmv. New, greenfield kilns\109\, that elect to
comply with the 100 ppmv carbon monoxide standard, however, must also
comply with a 50 ppmv hydrocarbon standard. New and existing sources
that elect to comply with the 100 ppmv carbon monoxide standard,
including new greenfield kilns that elect to comply with the carbon
monoxide standard and 50 ppmv hydrocarbon standard, must also
demonstrate compliance with the 20 ppmv hydrocarbon standard during the
comprehensive performance test. However, continuous hydrocarbon
monitoring following the performance test is not required.
---------------------------------------------------------------------------

\109\ A greenfield cement kiln is a kiln that commenced
construction or reconstruction after April 19, 1996 at a site where
no cement kiln previously existed, irrespective of the class of kiln
(i.e., nonhazardous waste or hazardous waste burning). A newly
constructed or reconstructed cement kiln at an existing site is not
classified as a greenfield cement kiln, and is subject to the same
carbon monoxide and hydrocarbon standards as an existing cement kiln.
---------------------------------------------------------------------------

For cement kilns with bypass or midkiln sampling systems, existing
cement kilns are required to comply with either a carbon monoxide
standard of 100 ppmv or a hydrocarbon standard of 10 ppmv. Both
standards apply to combustion gas sampled in the bypass or a midkiln
sampling port that samples representative kiln gas. See Sec. Sec.
63.1204(a)(5) and (b)(5). The rationale for these decisions are
discussed in the September 1999 final rule (64 FR at 52885). We view
the standards for hydrocarbons and carbon monoxide as unaffected by the
Court's vacature of the challenged regulations in its decision of July
24, 2001. We therefore are not proposing these standards for cement
kilns, but rather are mentioning them here for the reader's
convenience.

H. What Are the Standards for Destruction and Removal Efficiency?

The destruction and removal efficiency (DRE) standard is a
surrogate to control emissions of organic hazardous air pollutants
other than dioxin/furans. The standard for existing and new lightweight
aggregate kilns requires 99.99% DRE for each principal organic
hazardous constituent, except that 99.9999% DRE is required if
specified dioxin-listed hazardous wastes are burned. See Sec. Sec.
63.1204(c). The rationale for these decisions are discussed in the
September 1999 final rule (64 FR at 52890). We view the standards for
DRE as unaffected by the Court's vacature of the challenged regulations
in its decision of July 24, 2001. We therefore are not proposing these
standards for cement kilns, but rather are mentioning them here for the
reader's convenience.

IX. How Did EPA Determine the Proposed Emission Standards for Hazardous
Waste Burning Lightweight Aggregate Kilns?

In this section, the basis for the proposed emission standards is
discussed. See proposed Sec. 63.1221. The proposed emission limits
apply to the stack gases from lightweight aggregate kilns that burn
hazardous waste and are summarized in the table below:

Proposed Standards for Existing and New Lightweight Aggregate Kilns
------------------------------------------------------------------------
Emission standard \1\
Hazardous air pollutant or -------------------------------------------
surrogate Existing sources New sources
------------------------------------------------------------------------
Dioxin and furan............ 0.40 ng TEQ/dscm.... 0.40 ng TEQ/dscm.
Mercury \2\................. 67 [mu]g/dscm....... 67 [mu]g/dscm.
Particulate Matter.......... 57 mg/dscm (0.025 gr/ 23 mg/dscm (0.0099
dscf). gr/dscf).
Semivolatile metals \3\..... 3.1 x 10-4 lb/MMBtu 2.4 x 10-5 lb/MMBtu
and 250 [mu]g/dscm. and 43 [mu]g/dscm.
Low volatile metals \3\..... 9.5 x 10-5 lb/MMBtu 3.2 x 10-5 lb/MMBtu
and 110 [mu]g/dscm. and 110 [mu]g/dscm.
Hydrogen chloride and 600 ppmv............ 600 ppmv.
chlorine gas \4\.
Hydrocarbons 5, 6........... 20 ppmv (or 100 ppmv 20 ppmv (or 100 ppmv
carbon monoxide). carbon monoxide).

[[Page 21262]]

Destruction and removal For existing and new sources, 99.99% for
efficiency. each principal organic hazardous
constituent (POHC). For sources burning
hazardous wastes F020, F021, F022, F023,
F026, or F027, however, 99.9999% for each
POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ Mercury standard is an annual limit.
\3\ Standards are expressed as mass of pollutant emissions contributed
by hazardous waste per million British thermal unit contributed by the
hazardous waste.
\4\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\5\ Sources that elect to comply with the carbon monoxide standard must
demonstrate compliance with the hydrocarbon standard during the
comprehensive performance test.
\6\ Hourly rolling average. Hydrocarbons reported as propane.

A. What Are the Proposed Standards for Dioxin and Furan?

We are proposing to establish standards for existing and new
lightweight aggregate kilns that limit emissions of dioxin and furans
to 0.40 ng TEQ/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Dioxin and furan emissions for existing lightweight aggregate kilns
are currently limited by Sec. 63.1205(a)(1) to 0.20 ng TEQ/dscm or
rapid quench of the flue gas at the exit of the kiln to less than
400[deg]F. This standard was promulgated in the Interim Standards Rule
(See 67 FR at 6797).
Since promulgation of the September 1999 final rule, we have
obtained additional dioxin/furan emissions data. We now have compliance
test emissions data for all lightweight aggregate kilns that burn
hazardous waste. The compliance test dioxin/furan emissions in our
database range from approximately 0.9 to 58 ng TEQ/dscm.
Quenching kiln gas temperatures at the exit of the kiln so that gas
temperatures at the inlet to the particulate matter control device are
below the temperature range of optimum dioxin/furan formation (400-
750[deg]F) may be problematic for some of these sources. Some of these
sources have extensive (long) duct-work between the kiln exit and the
inlet to the control device. For these sources, quenching the gases at
the kiln exit to a low enough temperature to limit dioxin/furan
formation may conflict with the source's ability to avoid acid gas dew
point related problems in the long duct-work and control device. As a
result, some sources quench the kiln exit gases to a temperature that
is in the optimum temperature range for surface-catalyzed dioxin/furan
formation. Available compliance test emissions data indicate that inlet
temperatures to the control device range from 435-450[deg]F. This means
that temperatures in the duct-work are higher and well within the range
of optimum dioxin/furan formation.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
Emissions Approach described in Part Two, Section VI above. The
calculated floor is 14 ng TEQ/dscm, which considers emissions
variability. However, the current interim emission standard--0.20 ng
TEQ/dscm or rapid quench of the flue gas at the exit of the kiln to
less than 400[deg]F--is a regulatory limit that is relevant in
identifying the floor level because it fixes a level of performance for
the source category. We estimate that sources achieving the ``rapid
quench of the flue gas at the exit of the kiln to less than 400[deg]F''
part of the current standard can emit up to 6.1 ng TEQ/dscm. Given that
all sources are achieving the interim standard and that the interim
standard is judged as more stringent than the calculated MACT floor,
the dioxin/furan floor level can be no less stringent than the current
regulatory limit.\110\ We are, therefore, proposing the dioxin/furan
floor level as the current emission standard of 0.20 ng TEQ/dscm or
rapid quench of the flue gas at the exit of the kiln to less than
400[deg]F. This emission level is being achieved by all sources because
it is the interim standard. In addition, there are no emissions
reductions for existing lightweight aggregate kilns to comply with the
floor level.
---------------------------------------------------------------------------

\110\ Even though all sources have recently demonstrated
compliance with the interim standards, the dioxin/furan data in our
data base preceded the compliance demonstration. This explains why
we have emissions data that are higher than the interim standard.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated activated carbon injection as beyond-the-floor control
for further reduction of dioxin/furan emissions. Activated carbon has
been demonstrated for controlling dioxin/furans in various combustion
applications; however, no lightweight aggregate kiln that burns
hazardous waste uses activated carbon injection. We evaluated a beyond-
the-floor level of 0.40 ng TEQ/dscm, which represents a level that is
considered routinely achievable using activated carbon injection. In
addition, we assumed for costing purposes that lightweight aggregate
kilns needing activated carbon injection to achieve the beyond-the-
floor level would install the activated carbon injection system after
the existing particulate matter control device and add a new, smaller
baghouse to remove the injected carbon with the adsorbed dioxin/furans.
We chose this costing approach to address potential concerns that
injected carbon may interfere with lightweight aggregate dust use practices.
The national incremental annualized compliance cost for lightweight
aggregate kilns to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $1.8 million and would
provide an incremental reduction in dioxin/furan emissions beyond the
MACT floor controls of 1.9 grams TEQ per year. Nonair quality health
and environmental impacts and energy effects were evaluated to estimate
the nonair quality health and environmental impacts between activated
carbon injection and controls likely to be used to meet the floor
level. We estimate that this beyond-the-floor option would increase the
amount of solid waste generated by 550 tons per year and would require
sources to use an additional 1 million kW-hours per year beyond the
requirements to achieve the floor level. The costs associated with
these impacts are accounted for in the national compliance cost estimates.
Therefore, based on these factors and costs of approximately $0.95
million per additional gram of dioxin/furan TEQ

[[Page 21263]]

removed, we are proposing a beyond-the-floor standard of 0.40 ng TEQ/
dscm for existing lightweight aggregate kilns. We judge that the cost
to achieve this beyond-the-floor level is warranted given our special
concern about dioxin/furan. Dioxin/furan are some of the most toxic
compounds known due to their bioaccumulation potential and wide range
of health effects, including carcinogenesis, at exceedingly low doses.
Exposure via indirect pathways is a chief reason that Congress singled
our dioxin/furan for priority MACT control in CAA section 112(c)(6).
See S. Rep. No. 128, 101st Cong. 1st Sess. at 154-155. In addition, we
note that a beyond-the-floor standard of 0.40 ng TEQ/dscm is consistent
with historically controlled levels under MACT for hazardous waste
incinerators and cement kilns, and Portland cement plants. See
Sec. Sec. 63.1203(a)(1), 63.1204(a)(1), and 63.1343(d)(3). Also, EPA
has determined previously in the 1999 Hazardous Waste Combustor MACT
final rule that dioxin/furan in the range of 0.40 ng TEQ/dscm or less
are necessary for the MACT standards to be considered generally
protective of human health under RCRA (using the 1985 cancer slope
factor), thereby eliminating the need for separate RCRA standards under
the authority of RCRA section 3005(c)(3) and 40 CFR 270.10(k). Finally,
we note that this decision is not inconsistent with EPA's decision not
to promulgate beyond-the-floor standards for dioxin/furan for hazardous
waste burning lightweight aggregate kilns, cement kilns, and
incinerators at cost-effectiveness values in the range of $530,000 to
$827,000 per additional gram of dioxin/furan TEQ removed. See 64 FR at
52892, 52876, and 52961. In those cases, EPA determined that
controlling dioxin/furan emissions from a level of 0.40 ng TEQ/dscm to
a beyond-the-floor level of 0.20 ng TEQ/dscm was not warranted because
dioxin/furan levels below 0.40 ng TEQ/dscm are generally considered to
be below the level of health risk concern.
We specifically request comment on whether this beyond-the-floor
standard is warranted.
3. What Is the Rationale for the MACT Floor for New Sources?
Dioxin and furan emissions for new lightweight aggregate kilns are
currently limited by Sec. 63.1205(b)(1) to 0.20 ng TEQ/dscm or rapid
quench of the flue gas at the exit of the kiln to less than 400[deg]F.
This standard was promulgated in the Interim Standards Rule (See 67 FR
at 6797).
The calculated MACT floor for new sources would be 1.3 ng TEQ/dscm,
which considers emissions variability, or rapid quench of the flue gas
at the exit of the kiln to less than 400[deg]F. This is an emission
level that the single best performing source identified by the
Emissions Approach. However, we are concerned that the calculated floor
level of 1.3 ng TEQ/dscm is not duplicable by all sources using
temperature control because we estimate that sources rapidly quenching
the flue gas at the exit of the kiln to less than 400[deg]F can emit up
to 6.1 ng TEQ/dscm. Therefore, we are proposing the floor as the
current emission standard of 0.20 ng TEQ/dscm or rapid quench of the
flue gas at the exit of the kiln to less than 400[deg]F.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated activated carbon injection as beyond-the-floor control
for further reduction of dioxin/furan emissions, and considered a
beyond-the-floor level of 0.40 ng TEQ/dscm, which represents a level
that is considered routinely achievable with activated carbon
injection. In addition, we assumed for costing purposes that a new
lightweight aggregate kiln will install the activated carbon injection
system after the existing particulate matter control device and add a
new, smaller baghouse to remove the injected carbon with the adsorbed
dioxin/furan. The incremental annualized compliance cost for a new
source to meet this beyond-the-floor level, rather than comply with the
floor level, would be approximately $0.26 million and would provide an
incremental reduction in dioxin/furan emissions of 0.37 grams per year.
Nonair quality health, environmental impacts, and energy effects are
accounted for in the cost estimates. Therefore, based on these factors
and cost of $0.71 million per gram TEQ removed, we are proposing a
beyond-the-floor standard based on activated carbon injection. We
believe that the cost to achieve this beyond-the-floor level is
warranted given our special concern about dioxin/furan. Dioxin/furan
are some of the most toxic compounds known due to their bioaccumulation
potential and wide range of health effects, including carcinogenesis,
at exceedingly low doses. In addition, as discussed above, we note that
the beyond-the-floor emission level of 0.40 ng TEQ/dscm is consistent
with historically controlled levels under MACT for hazardous waste
incinerators and cement kilns, and Portland cement plants. See
Sec. Sec. 63.1203(a)(1), 63.1204(a)(1), and 63.1343(d)(3). EPA has
determined previously in the 1999 Hazardous Waste Combustor MACT final
rule that dioxin/furan in the range of 0.40 ng TEQ/dscm or less are
necessary for the MACT standards to be considered generally protective
of human health under RCRA, thereby eliminating the need for separate
RCRA standards.
We specifically request comment on whether this beyond-the-floor
standard is warranted.

B. What Are the Proposed Standards for Mercury?

We are proposing to establish standards for existing and new
lightweight aggregate kilns that limit emissions of mercury to 67 [mu]g/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Mercury emissions for existing lightweight aggregate kilns are
currently limited to 120 [mu]g/dscm by Sec. 63.1205(a)(2). Existing
lightweight aggregate kilns have the option to comply with an
alternative mercury standard that limits the hazardous waste maximum
theoretical emissions concentration (MTEC) of mercury to 120 [mu]g/
dscm.\111\ This standard was promulgated in the Interim Standards Rule
(See 67 FR at 6797). One lightweight aggregate facility with two kilns
uses a venturi scrubber to remove mercury from the flue gas stream and
the remaining sources limit the feed concentration of mercury in the
hazardous waste to control emissions.
---------------------------------------------------------------------------

\111\ MTEC is a term to compare metals and chlorine feedrates
across sources of different sizes. MTEC is defined as the metals or
chlorine feedrate divided by the gas flow rate and is expressed in
units of [mu]g/dscm.
---------------------------------------------------------------------------

We have compliance test emissions data for only one source;
however, we have normal emissions data for all sources. For most
sources, we have normal emissions data from more than one test
campaign. We used these emissions data to represent the average
emissions from a source even though we do not know whether the
emissions represent the high end, low end, or close to the average
emissions. The normal mercury stack emissions range from less than 1 to
47 [mu]g/dscm, while the highest compliance test emissions data is
1,050 [mu]g/dscm. These emissions are expressed as mass of mercury
(from all feedstocks) per unit volume of stack gas.
To identify the MACT floor, we evaluated all normal emissions data
using the SRE/Feed Approach. We considered normal stack emissions data
from all test campaigns.\112\ For example,

[[Page 21264]]

one source in our data base has normal emissions data for three
different testing campaigns: 1992, 1995, and 1999. Under this approach
we considered the emissions data from the three separate years or
campaigns. As explained earlier, we believe this approach better
captures the range of average emissions for a source than only
considering the most recent normal emissions. In addition, for sources
without control equipment to capture mercury, we assumed the sources
achieved a SRE of zero. The effect of this assumption is that the
sources (without control equipment for mercury) with the lower mercury
concentrations in the hazardous waste were identified as the better
performing sources.
---------------------------------------------------------------------------

\112\ Given that the majority of feedrate and emissions data for
mercury is normal, we do not believe it is appropriate to establish
a hazardous waste thermal emissions-based standard. We prefer to
establish emission standards under the hazardous waste thermal
emissions format using compliance test data because the metals
feedrate information from compliance tests that we use to apportion
emissions to calculate emissions attributable to hazardous waste are
more reliable than feedrate data measured during testing under
normal, typical operations.
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The calculated floor is 67 [mu]g/dscm, which considers emissions
variability, based on a hazardous waste maximum theoretical emissions
concentration (MTEC) of 42 [mu]g/dscm. This is an emission level that
the average of the best performing sources could be expected to achieve
in 99 of 100 future tests when operating under operating conditions
identical to the compliance test conditions during which the emissions
data were obtained. We estimate that this emission level is being
achieved by 57% of sources and would reduce mercury emissions by 8
pounds per year. If we were to adopt such a floor level, we are
proposing that sources comply with the limit on an annual basis because
it is based on normal emissions data. Under this approach, compliance
would not be based on the use of a total mercury continuous emissions
monitoring system because these monitors have not been adequately
demonstrated as a reliable compliance assurance tool at all types of
incinerator sources. Instead, a source would maintain compliance with
the mercury standard by establishing and complying with short-term
limits on operating parameters for pollution control equipment and
annual limits on maximum total mercury feedrate in all feedstreams.
In the September 1999 final rule, we acknowledged that a
lightweight aggregate kiln using properly designed and operated MACT
control technologies, including controlling the levels of metals in the
hazardous waste, may not be capable of achieving a given emission
standard because of process raw material contributions that might cause
an exceedance of the emission standard. To address this concern, we
promulgated a provision that allows sources to petition for alternative
standards provided they submit site-specific information that shows raw
material hazardous air pollutant contributions to the emissions prevent
the source from complying with the emission standard even though the
kiln is using MACT control. See Sec. 63.1206(b)(9).
Today's proposed floor of 67 [mu]g/dscm, which was based on a
hazardous waste MTEC of 42 [mu]g/dscm, may likewise necessitate such an
alternative because contributions of mercury in the raw materials and
fossil fuels at some sources may cause an exceedance of the emission
standard. The Agency intends to retain a source's ability to comply
with an alternative standard, and we request comment on two approaches
to accomplish this. The first approach would be to structure the
alternative standard similar to the petitioning process used under
Sec. 63.1206(b)(9). In the case of mercury for an existing lightweight
aggregate kiln, MACT would be defined as a hazardous waste feedrate
corresponding to an MTEC of 42 [mu]g/dscm. If we were to adopt this
approach, we would require sources, upon approval of the petition by
the Administrator, to comply with this hazardous waste MTEC on an
annual basis because it is based on normal emissions data. Under the
second approach, we would structure the alternative standard similar to
the framework used for the alternative interim standards for mercury
under Sec. 63.1206(b)(15). The operating requirement would be an
annual MTEC not to exceed 42 [mu]g/dscm. We also request comment on
whether there are other approaches that would more appropriately
provide relief to sources that cannot achieve a total stack gas
concentration standard because of emissions attributable to raw
material and nonhazardous waste fuels.
In comments submitted to EPA in 1997, Solite Corporation (Solite),
owner and operator of five \113\ of the seven lightweight aggregate
kilns, stated that the normal emissions data in our data base are
unrepresentative of average emissions of mercury because the normal
range of mercury concentrations in the hazardous waste burned during
the compliance and trial burn tests was not captured during the tests.
In their 1997 comments, Solite provided information on actual mercury
concentrations in the hazardous waste burn tanks over a year and a
quarter period. The information showed that 87% of the burn tanks
contained mercury at concentrations below the facility's detection
limit of 2 ppm. Additional analyses of a limited number of these
samples conducted at an off-site lab showed that the majority of
samples were actually less than 0.2 ppm.\114\
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\113\ Solite Corporation has four kilns at its Cascade facility
and three kilns at its Arvonia facility. However, only three kilns
and two kilns, respectively, can be fired with hazardous waste at
any one time. For purposes of today's proposal, Solite Corporation
is assumed to operate a total of five kilns.
\114\ A hazardous waste with a mercury concentration of 2 ppm
equates approximately to a mercury emissions level of 200-250 [mu]g/
dscm, and a source firing a hazardous waste with a mercury
concentration of 0.2 ppm approximately equates to 20-25 [mu]g/dscm.
The existing standard of 120 [mu]g/dscm allows a source to burn a
hazardous waste with a mercury concentration of approximately 1 ppm.
---------------------------------------------------------------------------

We examined the test reports of the five best performing sources
that are the basis of today's proposed floor level to determine the
concentration level of mercury in the hazardous wastes. The hazardous
waste burned by the best performing sources during the tests that
generated the normal emissions data had mercury concentrations that
ranged from 0.02 to 0.2 ppm.\115\ Even though the concentrations of
mercury in the hazardous waste seem low, we cannot judge how these snap
shot concentrations compare to long-term normal concentrations because
the majority of the burn tank concentration data submitted by Solite
are nondetect measurements at a higher detection limit.
---------------------------------------------------------------------------

\115\ These mercury concentrations were analyzed by an off-site
lab that had equipment capable of detecting mercury at lower
concentrations. Sixteen of the 27 measurements of the best
performers were reported as non-detects.
---------------------------------------------------------------------------

Solite informed us in July 2003 that they are in the process of
upgrading the analysis equipment at their on-site laboratory. Once
completed, Solite expects to be capable of detecting mercury in the
hazardous waste at concentrations of 0.2 ppm. Solite also indicated
that they intend to assemble and submit to EPA several months of burn
tank concentration data analyzed with the new equipment. We will add
these data to the docket of today's proposal once available. As we
discussed for cement kilns for mercury, we are requesting comment on
approaches to establish a hazardous waste feed concentration standard
based on long-term feed concentrations of mercury in the hazardous
waste. Likewise, we invite comments on establishing a mercury feed

[[Page 21265]]

concentration standard for lightweight aggregate kilns.
We also invite comment on whether we should judge an annual limit
of 67 [mu]g/dscm as less stringent than either the current emission
standard of 120 [mu]g/dscm or the hazardous waste MTEC of mercury of
120 [mu]g/dscm for lightweight aggregate kilns (so as to avoid any
backsliding from a current level of performance achieved by all
sources, and hence, the level of minimal stringency at which EPA could
calculate the MACT floor). In order to comply with the current emission
standard, generally a source must conduct manual stack sampling to
demonstrate compliance with the mercury emission standard and then
establish a maximum mercury feedrate limit based on operations during
the performance test. Following the performance test, the source
complies with a limit on the maximum total mercury feedrate in all
feedstreams on a 12-hour rolling average (not an annual average).
Alternatively, a source can elect to comply with a hazardous waste MTEC
of mercury of 120 [mu]g/dscm that would require the source to limit the
mercury feedrate in the hazardous waste on a 12-hour rolling average.
The floor level of 67 [mu]g/dscm proposed today would allow a source to
feed more variable mercury-containing feedstreams (e.g., a hazardous
waste with a mercury MTEC greater than 120 [mu]g/dscm) than the current
12-hour rolling average because today's proposed floor level is an
annual limit. For example, the concentration of mercury in the
hazardous waste exceeded a hazardous waste MTEC of 120 [mu]g/dscm in a
minimum of 13% of the burn tanks based on the data submitted by Solite
in their 1997 comments (discussed above). As mentioned above, Solite
intends to submit several months of burn tank concentration data using
upgraded analysis equipment at their on-site laboratory that we will
consider when comparing the relative stringency of an annual limit of
67 [mu]g/dscm and a short-term limit of 120 [mu]g/dscm.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified three potential beyond-the-floor techniques for
control of mercury: (1) Activated carbon injection; (2) control of
mercury in the hazardous waste feed; and (3) control of mercury in the
raw materials and auxiliary fuels. For reasons discussed below, we are
not proposing a beyond-the-floor standard for mercury.
Use of Activated Carbon Injection. We evaluated activated carbon
injection as beyond-the-floor control for further reduction of mercury
emissions. Activated carbon has been demonstrated for controlling
mercury in several combustion applications; however, currently no
lightweight aggregate kiln that burns hazardous waste uses activated
carbon injection. Given this lack of experience using activated carbon
injection, we made a conservative assumption that the use of activated
carbon injection will provide 70% mercury control and evaluated a
beyond-the-floor level of 20 [mu]g/dscm. In addition, for costing
purposes we assumed that sources needing activated carbon injection to
achieve the beyond-the-floor level would install the activated carbon
injection system after the existing baghouse and add a new, smaller
baghouse to remove the injected carbon with the adsorbed mercury. We
chose this costing approach to address potential concerns that injected
carbon may interfere with lightweight aggregate kiln dust use practices.
The national incremental annualized compliance cost for lightweight
aggregate kilns to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $1.1 million and would
provide an incremental reduction in mercury emissions beyond the MACT
floor controls of 11 pounds per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
impacts between activated carbon injection and controls likely to be
used to meet the floor level. We estimate that this beyond-the-floor
option would increase the amount of solid waste generated by 270 tons
per year and would require sources to use an additional 1.2 million kW-
hours per year beyond the requirements to achieve the floor level. The
costs associated with these impacts are accounted for in the national
annualized compliance cost estimates. Therefore, based on these factors
and costs of approximately $209 million per additional ton of mercury
removed, we are not proposing a beyond-the-floor standard based on
activated carbon injection.
Feed Control of Mercury in the Hazardous Waste. We also evaluated a
beyond-the-floor level of 54 [mu]g/dscm, which represents a 20%
reduction from the floor level. We chose a 20% reduction as a level
representing the practicable extent that additional feedrate control of
mercury in hazardous waste (beyond feedrate control that may be
necessary to achieve the floor level) can be used and still achieve
modest emissions reductions.\116\ The national incremental annualized
compliance cost for lightweight aggregate kilns to meet this beyond-
the-floor level rather than comply with the floor controls would be
approximately $0.3 million and would provide an incremental reduction
in mercury emissions beyond the MACT floor controls of 3 pounds per
year. Nonair quality health and environmental impacts and energy
effects were also evaluated. Therefore, based on these factors and
costs of approximately $229 million per additional ton of mercury
removed, we are not proposing a beyond-the-floor standard based on feed
control of mercury in the hazardous waste.
---------------------------------------------------------------------------

\116\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume V: Emission Estimates and Engineering
Costs'', March 2004, Chapter 4.
---------------------------------------------------------------------------

Feed Control of Mercury in the Raw Materials and Auxiliary Fuels.
Lightweight aggregate kilns could achieve a reduction in mercury
emissions by substituting a raw material containing a lower level of
mercury for a primary raw material with a higher level. We believe that
this beyond-the-floor option would be even less cost-effective than
either of the options discussed above, however. Given that sources are
sited near the supply of the primary raw material, transporting large
quantities of an alternate source of raw materials, even if available,
is likely to be cost-prohibitive, especially considering the small
expected emissions reductions that would result.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of mercury would be an appropriate
control option for sources. Two facilities typically burn hazardous
waste at a fuel replacement rate of 100%, while one facility has burned
a combination of fuel oil and natural gas in addition to the hazardous
waste. We considered switching only to natural gas as the auxiliary
fuel as a potential beyond-the-floor option. We do not believe that
switching to natural gas is a viable control option for the same
reasons discussed above for cement kilns.
For the reasons discussed above, we propose to establish the
emission standard for existing lightweight aggregate kilns at 67 [mu]g/
dscm. If we were to adopt such a standard, we are proposing that
sources comply with the standard on an annual basis because it is based
on normal emissions data.

[[Page 21266]]

3. What Is the Rationale for the MACT Floor for New Sources?
Mercury emissions from new lightweight aggregate kilns are
currently limited to 120 [mu]g/dscm by Sec. 63.1205(b)(2). This
standard was promulgated in the Interim Standards Rule (see 67 FR at 6797).
The MACT floor for new sources for mercury would be 67 [mu]g/dscm,
which considers emissions variability. This is an emission level that
the single best performing source identified with the SRE/Feed Approach
could be expected to achieve in 99 of 100 future tests when operating
under operating conditions identical to the compliance test conditions
during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified the same three potential beyond-the-floor techniques
for control of mercury: (1) Use of activated carbon; (2) control of
mercury in the hazardous waste feed; and (3) control of the mercury in
the raw materials and auxiliary fuels.
Use of Activated Carbon Injection. We evaluated activated carbon
injection as beyond-the-floor control for further reduction of mercury
emissions. We made a conservative assumption that the use of activated
carbon injection will provide 70% mercury control and evaluated a
beyond-the-floor level of 20 [mu]g/dscm. The incremental annualized
compliance cost for a new lightweight aggregate kiln with average gas
flow rate to meet this beyond-the-floor level, rather than comply with
the floor level, would be approximately $0.26 million and would provide
an incremental reduction in mercury emissions of approximately 42
pounds per year. Nonair quality health and environmental impacts and
energy effects are accounted for in the national annualized compliance
cost estimates. Therefore, based on these factors and costs of $12
million per ton of mercury removed, we are not proposing a beyond-the-
floor standard based on activated carbon injection for new sources.
Feed Control of Mercury in the Hazardous Waste. We also believe
that the expense for further reduction in mercury emissions based on
further control of mercury concentrations in the hazardous waste is not
warranted. A beyond-the-floor level of 54 [mu]g/dscm, which represents
a 20% reduction from the floor level, would result in little additional
mercury reductions. For similar reasons discussed above for existing
sources, we conclude that a beyond-the-floor standard based on
controlling the mercury in the hazardous waste feed would not be
justified because of the costs coupled with estimated emission reductions.
Feed Control of Mercury in the Raw Materials and Auxiliary Fuels.
Lightweight aggregate kilns could achieve a reduction in mercury
emissions by substituting a raw material containing lower levels of
mercury for a primary raw material with a higher level. For a new
source at an existing lightweight aggregate plant, we believe that this
beyond-the-floor option would not be cost-effective due to the costs of
transporting large quantities of an alternate source of raw materials
to the facility. Given that the plant site already exists and sited
near the source of raw material, replacing the raw materials at the
plant site with lower mercury-containing materials would be the
source's only option. For a new lightweight aggregate kiln constructed
at a new site--a greenfield site \117\--we are not aware of any
information and data from a source that has undertaken or is currently
located at a site whose raw materials are low in mercury which would
consistently decrease mercury emissions. Further, we are uncertain as
to what beyond-the-floor standard would be achievable using a lower, if
it exists, mercury-containing raw material. Although we are doubtful
that selecting a new plant site based on the content of metals in the
raw material is a realistic beyond-the-floor option considering the
numerous additional factors that go into such a decision, we solicit
comment on whether and what level of a beyond-the-floor standard based
on controlling the level of mercury in the raw materials is appropriate.
---------------------------------------------------------------------------

\117\ A greenfield source is a kiln constructed at a site where
no lightweight aggregate kiln previously existed; however, a newly
constructed or reconstructed kiln at an existing site would not be
considered as a greenfield kiln.
---------------------------------------------------------------------------

We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of mercury would be an appropriate
control option for sources. We considered using natural gas in lieu of
a fuel containing higher concentrations of mercury as a potential
beyond-the-floor option. As discussed for existing sources, we are
concerned about the availability of the natural gas infrastructure in
all regions of the United States and believe that using natural gas
would not be a viable control option for all new sources. Therefore, we
are not proposing a beyond-the-floor standard based on limiting mercury
in the raw material feed and auxiliary fuels.
Therefore, we propose a mercury standard of 67 [mu]g/dscm for new
sources. If we were to adopt such a standard, we are proposing that
sources comply with the standard on an annual basis because it is based
on normal emissions data.

C. What Are the Proposed Standards for Particulate Matter?

We are proposing to establish standards for existing and new
lightweight aggregate kilns that limit emissions of particulate matter
to 0.025 and 0.0099 gr/dscf, respectively. This standard would control
unenumerated HAP metals in hazardous waste, and all non-Hg HAP metals
in the raw material and fossil fuel inputs to the kiln.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Particulate matter emissions for existing lightweight aggregate
kilns are currently limited to 0.025 gr/dscf (57 mg/dscm) by Sec.
63.1205(a)(7). This standard was promulgated in the Interim Standards
Rule (See 67 FR at 6797). The particulate matter standard is a
surrogate control for the non-mercury metal HAP. All lightweight
aggregate kilns control particulate matter with baghouses.
We have compliance test emissions data for all lightweight
aggregate kiln sources. For most sources, we have compliance test
emissions data from more than one compliance test campaign. Our
database of particulate matter stack emissions range from 0.001 to
0.042 gr/dscf.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
APCD Approach. The calculated floor is 0.029 gr/dscf, which considers
emissions variability. This is an emission level that the average of
the best performing sources could be expected to achieve in 99 of 100
future tests when operating under operating conditions identical to the
compliance test conditions during which the emissions data were
obtained. The calculated floor level of 0.029 gr/dscf is less stringent
than the interim standard of 0.025 gr/dscf, which is a regulatory limit
relevant in identifying the floor level (so as to avoid any backsliding
from a current level of performance achieved by all lightweight
aggregate kilns, and hence, the level of minimal stringency at which
EPA could calculate the MACT floor). Therefore, we are proposing the
floor level as the current emission standard of 0.025 gr/dscf. This
emission level is currently being achieved by all sources.

[[Page 21267]]

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated improved particulate matter control to achieve a
beyond-the-floor standard of 29 mg/dscm (0.013 gr/dscf). The national
incremental annualized compliance cost for lightweight aggregate kilns
to meet this beyond-the-floor level rather than comply with the floor
controls would be approximately $0.32 million and would provide an
incremental reduction in particulate matter emissions beyond the MACT
floor controls of 8.6 tons per year. Nonair quality health and
environmental impacts and energy effects were evaluated to estimate the
impacts between further improvements to control particulate matter and
controls likely to be used to meet the floor level. We estimate that
this beyond-the-floor option would increase the amount of solid waste
generated by 9 tons per year beyond the requirements to achieve the
floor level. Therefore, based on these factors and costs of
approximately $36,600 per additional ton of particulate matter removed,
we are not proposing a beyond-the-floor standard based on improved
particulate matter control.
3. What Is the Rationale for the MACT Floor for New Sources?
Particulate matter emissions from new lightweight aggregate kilns
are currently limited to 0.025 gr/dscf by Sec. 63.1205(b)(7). This
standard was promulgated in the Interim Standards Rule (See 67 FR at
6797, February 13, 2002).
The MACT floor for new sources for particulate matter would be 23
mg/dscm (0.0099 gr/dscf), which considers emissions variability. This
is an emission level that the single best performing source identified
with the APCD Approach could be expected to achieve in 99 of 100 future
tests when operating under operating conditions identical to the
compliance test conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated improved particulate matter control to achieve a
beyond-the-floor standard. We evaluated a beyond-the-floor level of 12
mg/dscm (0.005 gr/dscf). The incremental annualized compliance cost for
a new lightweight aggregate kiln with an average gas flow rate to meet
this beyond-the-floor level, rather than comply with the floor level,
would be approximately $91,400 million and would provide an incremental
reduction in particulate matter emissions of approximately 2 tons per
year. Nonair quality health and environmental impacts and energy
effects were also evaluated and are included in the cost estimates.
Therefore, based on these factors and costs of approximately $45,600
per additional ton of particulate removed, we are not proposing a
beyond-the-floor standard based on improved particulate matter control
for new lightweight aggregate kilns. Therefore, we propose a
particulate matter standard of 2.3 mg/dscm (0.0099 gr/dscf) for new sources.

D. What Are the Proposed Standards for Semivolatile Metals?

We are proposing to establish standards for existing lightweight
aggregate kilns that limit emissions of semivolatile metals (cadmium
and lead, combined) to 3.1 x 10^-4 lbs semivolatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste and 250 [mu]g/dscm. The proposed standard
for new sources is 2.4 x 10^-5 lbs semivolatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste and 43 [mu]g/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Semivolatile metals emissions from existing lightweight aggregate
kilns are currently limited to 250 [mu]g/dscm by Sec. 63.1205(a)(3).
This standard was promulgated in the Interim Standards Rule (See 67 FR
at 6797). Lightweight aggregate kilns control emissions of semivolatile
metals with baghouses and/or by controlling the feed concentration of
semivolatile metals in the hazardous waste.
We have compliance test emissions data for all lightweight
aggregate kiln sources. For most sources, we have compliance test
emissions data from more than one compliance test campaign.
Semivolatile metal stack emissions range from approximately 1 to over
1,600 [mu]g/dscm. These emissions are expressed as mass of semivolatile
metals (from all feedstocks) per unit volume of stack gas. Hazardous
waste thermal emissions range from 3.0 x 10^-6 to 1.1 x
10^-3 lbs per million Btu. Hazardous waste thermal emissions
represent the mass of semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste. For
most lightweight aggregate kilns, lead was the major contributor to
semivolatile emissions.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 3.1 x 10^-4 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which considers
emissions variability. This is an emission level that the average of
the best performing sources could be expected to achieve in 99 of 100
future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 71%
of sources, and would reduce semivolatile metals emissions by 30 pounds
per year.
To put the proposed floor level in context for a hypothetical
lightweight aggregate kiln that gets 90% of its required heat input
from hazardous waste, a thermal emissions level of 3.1 x
10^-4 lbs semivolatile metals attributable to the hazardous
waste per million Btu heat input of the hazardous waste equates
approximately to a stack gas concentration of 300 [mu]g/dscm. This
estimated stack gas concentration does not include contributions to
emission from other semivolatile metals-containing materials such as
raw materials and fossil fuels. The additional contribution to stack
emissions of semivolatile metals in an average raw material is
estimated to range as high as 20 to 50 [mu]g/dscm. Thus, for the
hypothetical lightweight aggregate kiln the thermal emissions floor
level of 3.1 x 10^-4 lbs semivolatile metals attributable to
the hazardous waste per million Btu heat input of the hazardous waste
is estimated to be less than 350 [mu]g/dscm, which is higher than the
current interim standard of 250 [mu]g/dscm. Given that comparing the
proposed floor level to the interim standard requires numerous
assumptions (as just illustrated) including hazardous waste fuel
replacement rates, heat input requirements per ton of clinker,
concentrations of semivolatile metals in the raw material and fuels,
and system removal efficiency, we have included a more detailed
analysis in the background document.\118\ Our detailed analysis
indicates the proposed floor level could be less stringent than the
interim standard for some sources. In order to avoid any backsliding
from the current level of performance achieved by all lightweight
aggregate kilns, we propose a dual standard: the semivolatile metals
standard as both the

[[Page 21268]]

calculated floor level, expressed as a hazardous waste thermal
emissions level, and the current interim standard. This would ensure
that all sources are complying with a limit that is at least as
stringent as the interim standard.
---------------------------------------------------------------------------

\118\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 23.
---------------------------------------------------------------------------

In the September 1999 final rule, we acknowledged that a
lightweight aggregate kiln using properly designed and operated MACT
control technologies, including controlling the levels of metals in the
hazardous waste, may not be capable of achieving a given emission
standard because of mineral and process raw material contributions that
might cause an exceedance of the emission standard. To address this
concern, we promulgated a provision that allows kilns to petition for
alternative standards provided that they submit site-specific
information that shows raw material hazardous air pollutant
contributions to the emissions prevent the source from complying with
the emission standard even though the kiln is using MACT control. See
Sec. 63.1206(b)(9). If we were to adopt the proposed dual semivolatile
(and low volatile) metals standards approach, we propose to retain the
alternative standard provisions under Sec. 63.1206(b)(9) for
semivolatile metals (and low volatile metals). We invite comment on
this approach.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified three potential beyond-the-floor techniques for
control of semivolatile metals: (1) Improved particulate matter
control; (2) control of semivolatile metals in the hazardous waste
feed; and (3) control of the semivolatile metals in the raw materials
and fuels.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of semivolatile metals. Our data show that all
lightweight aggregate kilns are already achieving greater than 99.7%
system removal efficiency for semivolatile metals, with many attaining
99.9% removal. Thus, additional control of particulate matter are
likely to result in only modest additional reductions of semivolatile
metals emissions. We evaluated a beyond-the-floor level of 1.5 x
10^-4 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste,
which represents a 50% reduction in emissions from MACT floor levels.
The national incremental annualized compliance cost for lightweight
aggregate kilns to meet this beyond-the-floor level rather than to
comply with the floor controls would be approximately $84,200 and would
provide an incremental reduction in semivolatile metals emissions
beyond the MACT floor controls of 20 pounds per year. Nonair quality
health and environmental impacts and energy effects were evaluated to
estimate the impacts between further improvements to control
particulate matter and controls likely to be used to meet the floor
level. We estimate that this beyond-the-floor option would increase the
amount of solid waste generated by less than 10 tons per year and would
also require sources to use an additional 2,000 kW-hours per year
beyond the requirements to achieve the floor level. The costs
associated with these impacts are accounted for in the national
annualized compliance cost estimates. Therefore, based on these factors
and costs of approximately $7.6 million per additional ton of
semivolatile metals removed, we are not proposing a beyond-the-floor
standard based on improved particulate matter control.n
Feed Control of Semivolatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 2.5 x 10^-4 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which represents a 20%
reduction from the floor level. We chose a 20% reduction as a level
representing the practicable extent that additional feedrate control of
semivolatile metals in hazardous waste can be used and still achieve
appreciable emissions reductions. The national incremental annualized
compliance cost for lightweight aggregate kilns to meet this beyond-
the-floor level rather than comply with the floor controls would be
approximately $6,000 and would provide an incremental reduction in
semivolatile metals emissions beyond the MACT floor controls of less
than one pound per year. Nonair quality health and environmental
impacts and energy effects were evaluated and are included in the
national compliance cost estimates. Therefore, based on these factors
and costs of approximately $20 million per additional ton of
semivolatile metals removed, we are not proposing a beyond-the-floor
standard based on feed control of semivolatile metals in the hazardous
waste.
Feed Control of Semivolatile Metals in the Raw Materials and
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction
in semivolatile metal emissions by substituting a raw material
containing lower levels of cadmium and/or lead for a primary raw
material with higher levels of these metals. We believe that this
beyond-the-floor option would even be less cost-effective than either
of the options discussed above, however. Given that facilities are
sited near the primary raw material supply, acquiring and transporting
large quantities of an alternate source of raw materials is likely to
be cost-prohibitive. Therefore, we are not proposing a beyond-the-floor
standard based on limiting semivolatile metals in the raw material feed.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of semivolatile metals would be an
appropriate control option for sources. Two facilities typically burn
hazardous waste at a fuel replacement rate of 100%, while one facility
has burned a combination of fuel oil and natural gas in addition to the
hazardous waste. We considered switching only to natural gas as the
auxiliary fuel as a potential beyond-the-floor option. We do not
believe that switching to natural gas is a viable control option for
similar reasons discussed above for cement kilns.
For the reasons discussed above, we propose to establish the
emission standard for existing lightweight aggregate kilns at 3.1 x
10^-4 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste and
250 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
Semivolatile metals emissions from new lightweight aggregate kilns
are currently limited to 43 [mu]g/dscm by Sec. 63.1205(b)(3). This
standard was promulgated in the Interim Standards Rule (See 67 FR at 6797).
The MACT floor for new sources for semivolatile metals would be 2.4
x 10^-5 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu in the hazardous waste, which considers
emissions variability. This is an emission level that the single best
performing source identified with the SRE/Feed Approach could be
expected to achieve in 99 of 100 future tests when operating under
operating conditions identical to the compliance test conditions during
which the emissions data were obtained.
To put the proposed floor level in context for a hypothetical
lightweight aggregate kiln that gets 90% of its required heat input
from hazardous waste, a thermal emissions level of 2.4 x
10^-5 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste can
equate to a stack gas concentration as high as 60 [mu]g/dscm, including
contributions from typical raw materials. Thus, for the

[[Page 21269]]

hypothetical lightweight aggregate kiln the thermal emissions floor
level of 2.4 x 10^-5 lbs semivolatile metals emissions
attributable to the hazardous waste per million Btu heat input of the
hazardous waste is estimated to be as high as 60 [mu]g/dscm, which is
higher than the current interim standard of 43 [mu]g/dscm. In order to
avoid any backsliding from the current level of performance for a new
lightweight aggregate kiln source, we propose a dual standard: the
semivolatile metals standard as both the calculated floor level,
expressed as a hazardous waste thermal emissions level, and the current
interim standard. This would ensure that all sources are complying with
a limit that is at least as stringent as the interim standard. Thus,
the proposed MACT floor for new lightweight aggregate kilns is 2.4 x
10^-5 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste and
43 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified the same three potential beyond-the-floor techniques
for control of semivolatile metals: (1) Improved control of particulate
matter; (2) control of semivolatile metals in the hazardous waste feed;
and (3) control of semivolatile metals in the raw materials and fuels.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of semivolatile metals. We evaluated improved
control of particulate matter based on a state-of-the-art baghouse
using a high quality fabric filter bag material as beyond-the-floor
control for further reductions in semivolatile metals emissions. We
evaluated a beyond-the-floor level of 1.2 x 10^-5 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste. The incremental
annualized compliance cost for a new lightweight aggregate kiln with
average gas flowrate to meet this beyond-the-floor level, rather than
to comply with the floor level, would be approximately $0.11 million
and would provide an incremental reduction in semivolatile metals
emissions of approximately 13 pounds per year. Nonair quality health
and environmental impacts and energy effects were evaluated and are
included in the cost estimates. We estimate that this beyond-the-floor
option would increase the amount of solid waste generated by 3 tons per
year and would also require sources to use an additional 0.3 million
kW-hours per year beyond the requirements to achieve the floor level.
Therefore, based on these factors and costs of approximately $18
million per ton of semivolatile metals removed, we are not proposing a
beyond-the-floor standard based on improved particulate matter control
for new lightweight aggregate kilns.
Feed Control of Semivolatile Metals in the Hazardous Waste. We also
believe that the expense for further reduction in semivolatile metals
emissions based on further control of semivolatile metals
concentrations in the hazardous waste is not warranted. We considered a
beyond-the-floor level of 1.9 x 10^-5 lbs semivolatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste, which represents a 20% reduction from the
floor level. Nonair quality health and environmental impacts and energy
effects were evaluated and are included in the compliance cost
estimates. For similar reasons discussed above for existing sources, we
conclude that a beyond-the-floor standard based on controlling the
concentration of semivolatile metals levels in the hazardous waste feed
would not be justified because of the costs and estimated emission
reductions.
Feed Control of Semivolatile Metals in the Raw Materials and
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction
in semivolatile metals emissions by substituting a raw material
containing lower levels of cadmium and lead for a primary raw material
with a higher level. For a new source at an existing facility, we
believe that this beyond-the-floor option would not be cost-effective
due to the costs of transporting large quantities of an alternate
source of raw material to the facility. Given that the plant site
already exists and is sited near the source of raw material, replacing
the raw materials at the plant site with lower semivolatile metals-
containing materials would be the source's only option. For a kiln
constructed at a new greenfield site, we are not aware of any
information and data from a source that has undertaken or is currently
located at a site whose raw materials are inherently lower in
semivolatile metals that would consistently achieve reduced
semivolatile metals emissions. Further, we are uncertain as to what
beyond-the-floor standard would be achievable using, if it exists, a
lower semivolatile metals-containing raw material. Although we are
doubtful that selecting a new plant site based on the content of metals
in the raw material is a realistic beyond-the-floor option considering
the numerous additional factors that go into such a decision, we
solicit comment on whether and what level of a beyond-the-floor
standard based on controlling the level of semivolatile metals in the
raw materials is appropriate.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of semivolatile metals would be an
appropriate control option for sources. Two facilities typically burn
hazardous waste at a fuel replacement rate of 100%, while one facility
has burned a combination of fuel oil and natural gas in addition to the
hazardous waste. We considered switching only to natural gas as the
auxiliary fuel as a potential beyond-the-floor option. We do not
believe that switching to natural gas is a viable control option for
the same reasons discussed above for cement kilns.
For the reasons discussed above, we propose to establish the
emission standard for new lightweight aggregate kilns at 2.4 x
10^-5 lbs semivolatile metals emissions attributable to the
hazardous waste per million Btu heat content in the hazardous waste and
43 [mu]g/dscm.

E. What Are the Proposed Standards for Low Volatile Metals?

We are proposing to establish standards for existing lightweight
aggregate kilns that limit emissions of low volatile metals (arsenic,
beryllium, and chromium) to 9.5 x 10^-5 lbs low volatile
metals emissions attributable to the hazardous waste per million Btu
heat input of the hazardous waste and 110 [mu]g/dscm. The proposed
standard for new sources is 3.2 x 10^-5 lbs low volatile
metals emissions attributable to the hazardous waste per million Btu
heat input of the hazardous waste and 110 [mu]g/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Low volatile metals emissions from existing lightweight aggregate
kilns are currently limited to 110 [mu]g/dscm by Sec. 63.1205(a)(4).
This standard was promulgated in the Interim Standards Rule (see 67 FR
at 6797). Lightweight aggregate kilns control emissions of low volatile
metals with baghouses and/or by controlling the feed concentration of
low volatile metals in the hazardous waste.
We have compliance test emissions data for all lightweight
aggregate kiln sources. For most sources, we have compliance test
emissions data from more than one compliance test campaign. Low
volatile metal stack emissions range from approximately 16 to 200
[mu]g/dscm. These emissions are expressed as mass of low volatile
metals (from all feedstocks) per unit volume of

[[Page 21270]]

stack gas. Hazardous waste thermal emissions range from 9.7 x
10^-6 to 1.8 x 10^-4 lbs per million Btu. Hazardous
waste thermal emissions represent the mass of low volatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste. For most lightweight aggregate kilns,
chromium was the major contributor to low volatile emissions.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 9.5 x 10^-5 lbs
low volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which considers
emissions variability. This is an emission level that the average of
the best performing sources could be expected to achieve in 99 of 100
future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 57%
of sources and would reduce low volatile metals emissions by 30 pounds
per year.
To put the proposed floor level in context for a hypothetical
lightweight aggregate kiln that gets 90% of its required heat input
from hazardous waste, a thermal emissions level of 9.5 x
10^-5 lbs low volatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste
equates approximately to a stack gas concentration of 90 [mu]g/dscm.
This estimated stack gas concentration does not include contributions
to emission from other low volatile metals-containing materials such as
raw materials. The additional contribution to stack emissions of low
volatile metals in an average raw material is estimated to be 50 [mu]g/
dscm. Thus, for the hypothetical lightweight aggregate kiln the thermal
emissions floor level of 9.5 x 10^-5 lbs low volatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste is estimated to be 150 [mu]g/dscm, which
is higher than the current interim standard of 110 [mu]g/dscm. Given
that comparing the proposed floor level to the interim standard
requires numerous assumptions including hazardous waste fuel
replacement rates, heat input requirements per ton of clinker,
concentrations of low volatile metals in the raw material and fuels,
and system removal efficiency, we have included a more detailed
analysis in the background document.\119\ Our detailed analysis
indicates the proposed floor level could be less stringent than the
interim standard for some sources. In order to avoid any backsliding
from the current level of performance achieved by all lightweight
aggregate kilns, we propose a dual standard: the low volatile metals
standard as both the calculated floor level, expressed as a hazardous
waste thermal emissions level, and the current interim standard. This
would ensure that all sources are complying with a limit that is at
least as stringent as the interim standard.
---------------------------------------------------------------------------

\119\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 23.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified three potential beyond-the-floor techniques for
control of low volatile metals: (1) Improved particulate matter
control; (2) control of low volatile metals in the hazardous waste
feed; and (3) control of the low volatile metals in the raw materials
and fuels.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of low volatile metals. Our data show that all
lightweight aggregate kilns are already achieving greater than 99.8%
system removal efficiency for low volatile metals, with many attaining
99.9% or greater removal. Thus, additional control of particulate
matter emissions is likely to result in only a small increment in
reduction of low volatile metals emissions. We evaluated a beyond-the-
floor level of 4.7 x 10^-5 lbs low volatile metals emissions
attributable to the hazardous waste per million Btu heat input of the
hazardous waste. The national incremental annualized compliance cost
for lightweight aggregate kilns to meet this beyond-the-floor level
rather than comply with the floor controls would be approximately $0.24
million and would provide an incremental reduction in low volatile
metals emissions beyond the MACT floor controls of 28 pounds per year.
Nonair quality health and environmental impacts and energy effects were
evaluated to estimate the impacts between further improvements to
control particulate matter and controls likely to be used to meet the
floor level. We estimate that this beyond-the-floor option would
increase the amount of solid waste generated by less than 30 tons per
year and would also require sources to use an additional 46,000 kW-
hours of energy per year. Therefore, based on these factors and costs
of approximately $17 million per additional ton of low volatile metals
removed, we are not proposing a beyond-the-floor standard based on
improved particulate matter control.
Feed Control of Low Volatile Metals in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 7.6 x 10^-5 lbs low
volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste, which represents a 20%
reduction from the floor level. We chose a 20% reduction as a level
representing the practicable extent that additional feedrate control of
low volatile metals in hazardous waste (beyond feedrate control that
may be necessary to achieve the floor level) can be used and still
achieve modest emissions reductions. The national incremental
annualized compliance cost for lightweight aggregate kilns to meet this
beyond-the-floor level rather than comply with the floor controls would
be approximately $150,000 and would provide an incremental reduction in
low volatile metals emissions beyond the MACT floor controls of 14
pounds per year. Nonair quality health and environmental impacts and
energy effects were considered and are included in the cost estimates.
Therefore, based on these factors and costs of approximately $22
million per additional ton of low volatile metals removed, we are not
proposing a beyond-the-floor standard based on feed control of low
volatile metals in the hazardous waste.
Feed Control of Low Volatile Metals in the Raw Materials and
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction
in low volatile metal emissions by substituting a raw material
containing lower levels of arsenic, beryllium, and/or chromium for a
primary raw material with higher levels of these metals. We believe
that this beyond-the-floor option would even be less cost-effective
than either of the options discussed above, however. Given that
facilities are sited near the primary raw material supply, acquiring
and transporting large quantities of an alternate source of raw
materials is likely to be cost-prohibitive. Therefore, we are not
proposing a beyond-the-floor standard based on limiting low volatile
metals in the raw material feed.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of low volatile metals would be an
appropriate control option for sources. Two facilities typically burn
hazardous waste at a fuel replacement rate of 100%, while one facility
has burned a combination of fuel oil and natural gas in addition to the
hazardous waste. We considered switching only to natural gas as the
auxiliary fuel as a potential beyond-the-

[[Page 21271]]

floor option. We do not believe that switching to natural gas is a
viable control option for similar reasons discussed above for cement kilns.
For the reasons discussed above, we propose to establish the
emission standard for existing lightweight aggregate kilns at 9.5 x
10^-5 lbs low volatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste and
110 [mu]g/dscm.
3. What Is the Rationale for the MACT Floor for New Sources?
Low volatile metals emissions from new lightweight aggregate kilns
are currently limited to 110 [mu]g/dscm by Sec. 63.1205(b)(4). This
standard was promulgated in the Interim Standards Rule (See 67 FR at 6797).
The MACT floor for new sources for low volatile metals would be 3.2
x 10^-5 lbs low volatile metals emissions in the hazardous
waste per million Btu in the hazardous waste, which considers emissions
variability. This is an emission level that the single best performing
source identified with the SRE/Feed Approach could be expected to
achieve in 99 of 100 future tests when operating under operating
conditions identical to the compliance test conditions during which the
emissions data were obtained.
As discussed for existing sources, in order to avoid any
backsliding from the current level of performance for a new lightweight
aggregate kiln source, we propose a dual standard: the low volatile
metals standard as both the calculated floor level, expressed as a
hazardous waste thermal emissions level, and the current interim
standard. This would ensure that all sources are complying with a limit
that is at least as stringent as the interim standard. Thus, the
proposed MACT floor for new lightweight aggregate kilns is 3.2 x
10^-5 lbs low volatile metals emissions attributable to the
hazardous waste per million Btu heat input of the hazardous waste and
110 [mu]g/dscm.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We considered three potential beyond-the-floor techniques for
control of low volatile metals: (1) Improved particulate matter
control; (2) control of low volatile metals in the hazardous waste
feed; and (3) control of the low volatile metals in the raw materials
and fuels.
Improved Particulate Matter Control. Controlling particulate matter
also controls emissions of low volatile metals. We evaluated improved
control of particulate matter based on a state-of-the-art baghouse
using a high quality fabric filter bag material as beyond-the-floor
control for further reductions in low volatile metals emissions. We
evaluated a beyond-the-floor level of 1.6 x 10^-5 lbs low
volatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste. The incremental
annualized compliance cost for a new lightweight aggregate kiln with
average gas flowrate to meet this beyond-the-floor level, rather than
to comply with the floor level, would be approximately $0.11 million
and would provide an incremental reduction in low volatile metals
emissions of approximately 16 pounds per year. Nonair quality health
and environmental impacts and energy effects were evaluated and are
included in the cost estimates. We estimate that this beyond-the-floor
option would increase the amount of solid waste generated by 3 tons per
year and would also require sources to use an additional 0.3 million
kW-hours per year beyond the requirements to achieve the floor level.
Therefore, based on these factors and costs of nearly $14 million per
ton of low volatile metals removed, we are not proposing a beyond-the-
floor standard based on improved particulate matter control for new
lightweight aggregate kilns.
Feed Control of Low Volatile Metals in the Hazardous Waste. We also
believe that the expense for further reduction in low volatile metals
emissions based on further control of low volatile metals
concentrations in the hazardous waste is not warranted. We considered a
beyond-the-floor level of 2.6 x 10^-5 lbs low volatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste, which represents a 20% reduction from the
floor level. Nonair quality health and environmental impacts and energy
effects were evaluated and are included in the compliance cost
estimates. For similar reasons discussed above for existing sources, we
conclude that a beyond-the-floor standard based on controlling the
concentration of low volatile metals levels in the hazardous waste feed
would not be justified because of the costs and estimated emission
reductions.
Feed Control of Low Volatile Metals in the Raw Materials and
Auxiliary Fuels. Lightweight aggregate kilns could achieve a reduction
in low volatile metals emissions by substituting a raw material
containing lower levels of arsenic, beryllium, and/or chromium for a
primary raw material with a higher level. For a new source at an
existing facility, we believe that this beyond-the-floor option would
not be cost-effective due to the costs of transporting large quantities
of an alternate source of raw material to the facility. Given that the
plant site already exists and is sited near the source of raw material,
replacing the raw materials at the plant site with lower low volatile
metals-containing materials would be the source's only option. For a
kiln constructed at a new greenfield site, we are not aware of any
information and data from a source that has undertaken or is currently
located at a site whose raw materials are inherently lower in low
volatile metals that would consistently achieve reduced low volatile
metals emissions. Further, we are uncertain as to what beyond-the-floor
standard would be achievable using, if it exists, a lower low volatile
metals-containing raw material. Although we are doubtful that selecting
a new plant site based on the content of metals in the raw material is
a realistic beyond-the-floor option considering the numerous additional
factors that go into such a decision, we solicit comment on whether and
what level of a beyond-the-floor standard based on controlling the
level of low volatile metals in the raw materials is appropriate.
We also considered whether fuel switching to an auxiliary fuel
containing a lower concentration of low volatile metals would be an
appropriate control option for sources. Two facilities typically burn
hazardous waste at a fuel replacement rate of 100%, while one facility
has burned a combination of fuel oil and natural gas in addition to the
hazardous waste. We considered switching only to natural gas as the
auxiliary fuel as a potential beyond-the-floor option. We do not
believe that switching to natural gas is a viable control option for
the same reasons discussed above for cement kilns.
For the reasons discussed above, we propose to establish the
emission standard for new lightweight aggregate kilns at 3.2 x
10^-\5\ lbs low volatile metals emissions attributable to the
hazardous waste per million Btu heat content in the hazardous waste and
110 [mu]g/dscm.

F. What Are the Proposed Standards for Hydrogen Chloride and Chlorine Gas?

We are proposing to establish standards for existing and new
lightweight aggregate kilns that limit total chlorine emissions
(hydrogen chloride and chlorine gas, combined, reported as a chloride
equivalent) to 600 ppmv. Although we are also proposing to invoke CAA
section 112(d)(4) to establish alternative risk-based standards in lieu
of the MACT emission standards for total chlorine, the risk-based
standards would be capped at the

[[Page 21272]]

interim standards. Given that we are proposing MACT standards
equivalent to the interim standards--600 ppmv, an emission level you
are currently achieving--you would not be eligible for the section
112(d)(4) risk-based standards. See Part Two, Section XIII for
additional details.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Total chlorine emissions from existing cement kilns are limited to
600 ppmv by Sec. 63.1205(a)(6). This standard was promulgated in the
Interim Standards Rule (See 67 FR at 6797). One of the three
lightweight aggregate facilities uses a venturi scrubber to remove
total chlorine from the gas stream. The system removal efficiency (SRE)
achieved by this facility during compliance testing shows removal
efficiencies ranging from 96 to 99%. Sources at the other two
facilities do not use air pollution control equipment to capture
emissions of total chlorine, and, therefore, SREs are negligible.
The majority of the chlorine fed to the lightweight aggregate kiln
during a compliance test comes from the hazardous waste. In all but a
few cases the hazardous waste contribution to the total amount of
chlorine fed to the kiln represented at least 80% of the total loading
to the kiln. The proposed MACT floor control for total chlorine is, in
part, based on controlling the concentration of chlorine in the
hazardous waste. The chlorine concentration in the hazardous waste will
affect emissions of total chlorine at a given SRE because emissions
will increase as the chlorine loading increases.
We have compliance test emissions data for all lightweight
aggregate kiln sources. For most sources, we have compliance test
emissions data from more than one compliance test campaign. Total
chlorine emissions range from 14 to 116 ppmv for the source using a
venturi scrubber and range from 500 to 2,400 ppmv at sources without
scrubbing control equipment.
To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 3.0 lbs total chlorine
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste, which considers emissions variability.
This is an emission level that the average of the best performing
sources could be expected to achieve in 99 of 100 future tests when
operating under conditions identical to the compliance test conditions
during which the emissions data were obtained.
To put the proposed floor level in context for a hypothetical
lightweight aggregate kiln that gets 90% of its required heat input
from hazardous waste, a thermal emissions level of 3.0 lbs total
chlorine emissions attributable to the hazardous waste per million Btu
heat input of the hazardous waste equates approximately to a stack gas
concentration of 1,970 ppmv. This estimated stack gas concentration
does not include contributions to emission from other chlorine-
containing materials such as raw materials. Given that the calculated
floor level is less stringent than the current interim emission
standard of 600 ppmv. In order to avoid any backsliding from the
current level of performance achieved by all lightweight aggregate
kilns, we are proposing the floor standard as the current emission
standard of 600 ppmv. This emission level is currently being achieved
by all sources.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We considered a beyond-the-floor standard of 150 ppmv based on the
assumption that dry lime scrubbing will provide 75% control of hydrogen
chloride.\120\ In addition, for costing purposes we assumed that
lightweight aggregate kilns needing total chlorine reductions to
achieve the beyond-the-floor level would install the dry scrubbing
system after the existing particulate matter control device and add a
new, smaller baghouse to remove the products of the reaction and any
unreacted lime. We chose this conservative costing approach to address
potential concerns that unreacted lime and collected chloride and
sulfur salts may interfere with lightweight aggregate dust use practices.
---------------------------------------------------------------------------

\120\ We also considered controlling the chlorine levels in the
hazardous waste feed and controlling the chlorine levels in the raw
materials as potential beyond-the-floor techniques; however, it is
our judgment that they are not likely to be as cost-effective as dry
lime scrubbing.
---------------------------------------------------------------------------

The national incremental annualized compliance cost for lightweight
aggregate kilns to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $1.9 million and would
provide an incremental reduction in total chlorine emissions beyond the
MACT floor controls of 280 tons per year, for a cost-effectiveness of
$6,800 per additional ton of total chlorine removed. We evaluated
nonair quality health and environmental impacts and energy effects
associated with this beyond-the-floor standard and estimate that this
beyond-the-floor option would increase the amount of solid waste
generated by 12,700 tons per year and would also require sources to use
an additional 175,000 kW-hours per year and 31 million gallons of water
beyond the requirements to achieve the floor level.
We note that a cost of $6,800 per additional ton of total chlorine
removed is in the ``grey area'' between a cost the Agency has concluded
is cost-effective and a cost the Agency has concluded is not cost-
effective under other MACT rules. EPA concluded that a cost of $1,100
per ton of total chlorine removed for hazardous waste burning
lightweight aggregate kilns was cost-effective in the 1999 MACT final
rule. See 68 FR at 52900. EPA concluded, however, that a cost of
$45,000 per ton of hydrogen chloride removed was not cost-effective for
industrial boilers. See 68 FR at 1677. Consequently, we are concerned
that a cost of $6,800 per additional ton of total chlorine removed is
not warranted. Therefore, after considering cost-effectiveness and
nonair quality health and environmental impacts and energy effects, we
are not proposing a beyond-the-floor standard.
We specifically request comment on whether a beyond-the-floor
standard is warranted.
3. What Is the Rationale for the MACT Floor for New Sources?
Total chlorine emissions from new lightweight aggregate kilns are
currently limited to 600 ppmv by Sec. 63.1205(b)(6). This standard was
promulgated in the Interim Standards Rule (See 67 FR at 6797). The MACT
floor for new sources for total chlorine would be 0.93 lbs chlorine in
the hazardous waste per million Btu in the hazardous waste, which
considers emissions variability.
To put the proposed floor level in context for a hypothetical
lightweight aggregate kiln that gets 90% of its required heat input
from hazardous waste, a thermal emissions level of 0.93 lbs total
chlorine emissions attributable to the hazardous waste per million Btu
heat input of the hazardous waste equates approximately to a stack gas
concentration of 610 ppmv. This estimated stack gas concentration does
not include contributions to emission from other chlorine-containing
materials such as raw materials. Given that the calculated floor level
is less stringent than the current interim emission standard of 600
ppmv. In order to avoid any backsliding from the current standard for a
new lightweight aggregate kilns, we are proposing the floor standard as
the current emission standard of 600 ppmv.

[[Page 21273]]

4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
Similar to existing sources, we considered a beyond-the-floor
standard of 150 ppmv based on the assumption that dry lime scrubbing
will provide 75% control of hydrogen chloride. The incremental
annualized compliance cost for a new lightweight aggregate kiln with
average gas flowrate to meet this beyond-the-floor level, rather than
to comply with the floor level, would be approximately $0.42 million
and would provide an incremental reduction in total chlorine emissions
of approximately 150 tons per year for a cost-effectiveness of
approximately $2,800 per additional ton of total chlorine removed.
Nonair quality health and environmental impacts and energy effects were
evaluated and are included in the cost estimates. We estimate that this
beyond-the-floor option would increase the amount of solid waste
generated by 23 tons per year and would also require sources to use an
additional 0.3 million kW-hours per year and 2 million gallons of water
beyond the requirements to achieve the floor level.
A cost of $2,800 per additional ton of total chlorine removed is in
the ``grey area'' between a cost the Agency has concluded is cost-
effective and a cost the Agency has concluded is not cost-effective
under other MACT rules, as discussed above. Therefore, we are concerned
that a cost-effectiveness of $2,800 per additional ton of total
chlorine removed may not be warranted. After considering cost-
effectiveness and nonair quality health and environmental impacts and
energy effects, we are not proposing a beyond-the-floor standard.
We specifically request comment on whether a beyond-the-floor
standard is warranted.

G. What Are the Standards for Hydrocarbons and Carbon Monoxide?

Hydrocarbon and carbon monoxide standards are surrogates to control
emissions of organic hazardous air pollutants for existing and new
lightweight aggregate kilns. The standards limit hydrocarbons and
carbon monoxide concentrations to 20 ppmv or 100 ppmv. See Sec. Sec.
63.1205(a)(5) and (b)(5). Existing and new lightweight aggregate kilns
can elect to comply with either the hydrocarbon limit or the carbon
monoxide limit on a continuous basis. Sources that comply with the
carbon monoxide limit on a continuous basis must also demonstrate
compliance with the hydrocarbon standard during the comprehensive
performance test. However, continuous hydrocarbon monitoring following
the performance test is not required. The rationale for these decisions
are discussed in the September 1999 final rule (64 FR at 52900). We
view the standards for hydrocarbons and carbon monoxide as unaffected
by the Court's vacature of the challenged regulations in its decision
of July 24, 2001. We therefore are not proposing these standards for
lightweight aggregate kilns, but rather are mentioning them here for
the reader's convenience.
H. What Are the Standards for Destruction and Removal Efficiency?
The destruction and removal efficiency (DRE) standard is a
surrogate to control emissions of organic hazardous air pollutants
other than dioxin/furans. The standard for existing and new lightweight
aggregate kilns requires 99.99% DRE for each principal organic
hazardous constituent, except that 99.9999% DRE is required if
specified dioxin-listed hazardous wastes are burned. See Sec. Sec.
63.1205(c). The rationale for these decisions are discussed in the
September 1999 final rule (64 FR at 52902). We view the standards for
DRE as unaffected by the Court's vacature of the challenged regulations
in its decision of July 24, 2001. We therefore are not proposing these
standards for lightweight aggregate kilns, but rather are mentioning
them here for the reader's convenience.

X. How Did EPA Determine the Proposed Emission Standards for Hazardous
Waste Burning Solid Fuel-Fired Boilers?

The proposed standards for existing and new solid fuel-fired
boilers that burn hazardous waste are summarized in the table below.
See proposed Sec. 63.1216.

Proposed Standards for Existing and New Solid Fuel-Fired Boilers
------------------------------------------------------------------------
Emission standard \1\
Hazardous air pollutant or -------------------------------------------
surrogate Existing sources New sources
------------------------------------------------------------------------
Dioxin and furan............ 100 ppmv carbon 100 ppmv carbon
monoxide or 10 ppmv monoxide or 10 ppmv
hydrocarbons.. hydrocarbons.
Mercury..................... 10 [mu]g/dscm....... 10 [mu]g/dscm.
Particulate matter.......... 69 mg/dscm (0.030 gr/ 34 mg/dscm (0.015 gr/
dscf). dscf).
Semivolatile metals......... 170 [mu]g/dscm...... 170 [mu]g/dscm.
Low volatile metals......... 210 [mu]g/dscm...... 190 [mu]g/dscm.
Hydrogen chloride and 440 ppmv or the 73 ppmv or the
chlorine gas \2\. alternative alternative
emission limits emission limits
under Sec. under Sec.
63.1215. 63.1215.
Carbon monoxide or 100 ppmv carbon 100 ppmv carbon
hydrocarbons \3\. monoxide or 10 ppmv monoxide or 10 ppmv
hydrocarbons. hydrocarbons.
-----------------------------
Destruction and Removal For existing and new sources, 99.99% for
Efficiency. each principal organic hazardous
constituent (POHC). For sources burning
hazardous wastes F020, F021, F022, F023,
F026, or F027, however, 99.9999% for each
POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\3\ Hourly rolling average. Hydrocarbons reported as propane.

We considered whether fuel switching could be considered a control
technology to achieve MACT floor control. We investigated whether fuel
switching would achieve lower HAP emissions and whether it could be
technically achieved considering the existing design of solid fuel-
fired boilers. We also considered the availability of various types of
fuel. After considering these factors, we determined that fuel
switching is not an appropriate control technology for purposes of
determining the MACT floor level of control. This decision is based on
the overall effect of fuel switching on HAP emissions, technical

[[Page 21274]]

and design considerations, and concerns about fuel availability.
We determined that while fuel switching from coal to natural gas or
oil would decrease particulate matter and some metal HAP emissions,
emissions of some organic HAP would increase, resulting in uncertain
benefits.\121\ We believe that it is inappropriate in a MACT rulemaking
to consider as MACT a control option that potentially will decrease
emissions of one HAP while increasing emissions of another HAP. In
order to adopt such a strategy, we would need to assess the relative
risk associated with each HAP emitted, and determine whether requiring
the control in question would result in overall lower risk. Such an
analysis is not appropriate at this stage in the regulatory process.
For example, the term ``clean coal'' refers to coal that is lower in
sulfur content and not necessarily lower in HAP content. Data gathered
by EPA also indicates that within specific coal types HAP content can
vary significantly. Switching to a low sulfur coal may actually
increase emissions of some HAP. Therefore, it is not appropriate for
EPA to include fuel switching to a low sulfur coal as part of the MACT
standards for boilers that burn hazardous waste.
---------------------------------------------------------------------------

\121\ C. Leatherwood, ERG, to J. Eddinger, OAQPS, EPA,
Memorandum: Development of Fuel Switching Costs and Emission
Reductions for Industrial/Commercial/Institutional Boilers and
Process Heaters National Emission Standards for Hazardous Air
Pollutants, October 2002.
---------------------------------------------------------------------------

We also considered the availability of alternative fuel types.
Natural gas pipelines are not available in all regions of the U.S., and
natural gas is simply not available as a fuel for many solid fuel-fired
boilers. Moreover, even where pipelines provide access to natural gas,
supplies of natural gas may not be adequate. For example, it is common
practice in cities during winter months (or periods of peak demand) to
prioritize natural gas usage for residential areas before industrial
usage. Requiring EPA regulated combustion units to switch to natural
gas would place an even greater strain on natural gas resources.
Consequently, even where pipelines exist, some units would not be able
to run at normal or full capacity during these times if shortages were
to occur. Therefore, under any circumstances, there would be some units
that could not comply with a requirement to switch to natural gas.
In addition, we have significant concern that switching fuels would
be infeasible for sources designed and operated to burn specific fuel
types. Changes in the type of fuel burned by a boiler may require
extensive changes to the fuel handling and feeding system (e.g., a
stoker-fired boiler using coal as primary fuel would need to be
redesigned to handle fuel oil or gaseous fuel as the primary fuel).
Additionally, burners and combustion chamber designs are generally not
capable of handling different fuel types, and generally cannot
accommodate increases or decreases in the fuel volume and shape. Design
changes to allow different fuel use, in some cases, may reduce the
capacity and efficiency of the boiler. Reduced efficiency may result in
less complete combustion and, thus, an increase in organic HAP
emissions. For the reasons discussed above, we conclude that fuel
switching to cleaner solid fuels or to liquid or gaseous fuels is not
an appropriate criteria for identifying the MACT floor level of control
for solid fuel-fired boilers.

A. What Is the Rationale for the Proposed Standards for Dioxin and Furan?

The proposed standard for dioxin/furan for existing and new sources
is compliance with the proposed carbon monoxide or hydrocarbon (CO/HC)
emission standard and compliance with the proposed destruction and
removal efficiency (DRE) standard. The CO/HC and DRE standards control
emissions of organic HAPs in general, and are discussed in Sections G
and H below. This standard ensures that boilers operate under good
combustion practices as a surrogate for dioxin/furan control. Operating
under good combustion practices minimizes levels of products of
incomplete combustion, including potentially dioxin/furan, and organic
compounds that could be precursors for post-combustion formation of
dioxin/furan. The rationale for the dioxin/furan standard is discussed
below.
1. What Is the Rationale for the MACT Floor for Existing Sources?
The proposed MACT floor control for existing sources is compliance
with the proposed CO/HC emission standard and compliance with the
proposed DRE standard.
Solid fuel-fired boilers that burn hazardous waste cofire the
hazardous waste with coal at firing rates of 6-33% of total heat input.
We have dioxin/furan emission data for one source, and those emissions
are 0.07 ng TEQ/dscm.
Although dioxin/furan can be formed post-combustion in an
electrostatic precipitator or baghouse that is operated at temperatures
within the range of 400[deg] to 750[deg]F, the boiler for which we have
dioxin/furan emissions data is equipped with an electrostatic
precipitator that operated at 500[deg]F during the emissions test.
Although this is well within the optimum temperature range for
formation of dioxin/furan, dioxin/furan emissions were low. In
addition, this boiler fed chlorine at levels four times greater than
any other solid fuel boiler.\122\ We also have emissions data from 16
nonhazardous waste coal-fired boilers equipped with electrostatic
precipitators and baghouses operated at temperatures up to 480[deg]F,
all of which have dioxin/furan emissions below 0.3 ng TEQ/dscm.\123\ We
conclude from these data and the information discussed below that rapid
quench of post-combustion gas temperatures to below 400[deg]F--the
control technique that is the basis for the MACT standards for
hazardous waste burning incinerators, and cement and lightweight
aggregate kilns--is not the dominant dioxin/furan control mechanism for
coal-fired boilers.
---------------------------------------------------------------------------

\122\ Uncontrolled hydrogen chloride in combustion gas was
approximately 700 ppmv.
\123\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 2.
---------------------------------------------------------------------------

We believe that sulfur contributed by the coal fuel is a dominant
control mechanism by inhibiting formation of dioxin/furan. Coal
generally contributes from 65% to 95% percent of the boiler's heat
input with the remainder provided by hazardous waste fuel. The presence
of sulfur in combustor feedstocks has been shown to dramatically
inhibit the catalytic formation of dioxin/furan in downstream
temperature zones from 400[deg]F to 750[deg]F. High sulfur coals tend
to inhibit dioxin/furan formation better than low sulfur coals. Id.
Adsorption of any dioxin/furan that may be formed on coal fly ash,
and subsequent capture in the electrostatic precipitator or baghouse,
also may contribute to the low dioxin/furan emissions despite some
boilers operating at relatively high back-end gas temperatures. This
effect is similar to that of using activated carbon injection to
control dioxin/furan emissions. Adsorption of dioxin/furan on fly ash
is related to the carbon content of the fly ash, and, thus, the type of
coal burned. Id.
Operating under good combustion conditions to minimize emissions of
organic compounds such as polychlorinated biphenols, benzene, and
phenol that can be precursors to dioxin/furan formation is an important
requisite to control dioxin/furan emissions. Although sulfur-induced
inhibition may be the dominant mechanism to control dioxin/furan

[[Page 21275]]

emissions from coal-fired boilers, minimizing dioxin/furan precursors
by operating under good combustion practices certainly plays a part in
controlling dioxin/furan emissions.
We propose to use the CO/HC and DRE standards as surrogates to
ensure that boilers operate under good combustion conditions because
quantified levels of control provided by sulfur in the coal and
adsorption onto collected fly ash may not be replicable by the best
performing sources nor duplicable by other sources. Although coal
sulfur content may be a dominant factor affecting dioxin/furan
emissions, we do not know what minimum level of sulfur provides
significant control. Moreover, sulfur in coal causes emissions of
sulfur oxides, a major criteria pollutant, and particulate sulfates.
Similarly, we cannot quantify a minimum carbon content of coal that
would form carbonaceous fly ash with superior dioxin/furan adsorptive
properties. In addition, restricting coal types that may be burned
based on carbon content may have an adverse impact on energy production
at sources burning hazardous waste as fuel. (These considerations raise
the question of whether boilers operating under these conditions would
still be ``best'' performers when these adverse impacts are taken into
account.) For these reasons, and because we have emissions data from
only one source, we cannot establish a numerical dioxin/furan emission
standard.
Operating under good combustion practices is floor control because
all hazardous waste burning boilers are required by existing RCRA
regulations to operate under good combustion conditions to minimize
emissions of toxic organic compounds. See Sec. 266.104 requiring
compliance with DRE and CO/HC emission standards.\124\ We also find, as
required by CAA section 112(h)(1), that these proposed standards are
consistent with section 112(d)'s objective of reducing emissions of
these HAPs to the extent achievable.
---------------------------------------------------------------------------

\124\ Section 266.104 requires compliance with a CO limit of 100
ppmv or a HC limit of 20 ppmv, while we are proposing today a CO
limit of 100 ppmv or a HC limit of 10 ppmv (see Section X.H in the
text). Although today's proposed HC limit is more stringent than the
current limit for boilers, all solid fuel boilers chose to comply
with the 100 ppmv CO limit. Moreover, for those liquid-fuel fired
boilers that chose to comply with the 20 ppmv HC limit, their HC
emissions are below 10 ppmv.
---------------------------------------------------------------------------

We request comment on an alternative floor that would be
established as the highest dioxin/furan emission level in our data
base. Because we have dioxin/furan emission data from only one coal-
fired boiler that burns hazardous waste, we would combine that data
point with emissions data from coal-fired boilers that do not burn
hazardous waste since the factors that affect dioxin/furan emissions
from these boilers are not significantly influenced by hazardous waste.
These additional data would better represent the range of emissions
from coal-fired boilers. Under this approach, the dioxin/furan floor
would be an emission level of 0.30 ng TEQ/dscm. We would also use this
approach to establish the same floor for new sources.
Finally, we note that we propose to require a one-time dioxin/furan
emission test for sources that would not be subject to a numerical
dioxin/furan emission standard, such as solid fuel-fired boilers. As
discussed in Part Two, Section XIV.B below, the testing would assist in
developing both section 112(d)(6) standards and section 112(f) residual
risk standards.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
As discussed above, we propose to use the CO/HC and DRE standards
as surrogates to ensure good combustion conditions, and thus, control
of dioxin/furan emissions. We are not proposing beyond-the-floor
standards for CO/HC and DRE, as discussion in Sections G and H below.
We investigated use of activated carbon injection or, for sources
equipped with baghouses, catalytically impregnated fabric felt/membrane
filter materials to achieve a beyond-the-floor standard of 0.10 ng TEQ/
dscm.\125\ To estimate the cost-effectiveness of these beyond-the-floor
control techniques, we imputed dioxin/furan emissions levels for the
six sources for which we don't have measured emissions data. To impute
the missing emissions levels, we used the emissions data from the
hazardous waste burning boiler as well as the emissions data from
nonhazardous waste coal-fired boilers. It may be appropriate to meld
these emissions data because hazardous waste burning should not affect
dioxin/furan emissions from coal-fired boilers. In fact, the
nonhazardous waste coal-fired boilers had somewhat higher emissions
than the hazardous waste coal-fired boiler. (The emissions from the
nonhazardous waste coal-fired boilers may simply represent the range of
emissions that could be expected from hazardous waste coal-fired
boilers, as well, given that we have emissions data from only one
hazardous waste boiler.)
---------------------------------------------------------------------------

\125\ We considered a beyond-the-floor standard of 0.20 ng TEQ/
dscm but determined that it may not result in emissions reductions
because the majority of sources (the hazardous waste coal-fired
boiler and the nonhazardous waste coal-fired boilers) appear to emit
dioxin/furan at levels below 0.20 ng TEQ/dscm.
---------------------------------------------------------------------------

The national incremental annualized compliance cost for solid fuel-
fired boilers to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $3.4 million and would
provide an incremental reduction in dioxin/furan emissions beyond the
MACT floor controls of 0.26 grams TEQ tons per year. We also evaluated
the nonair quality health and environmental impacts and energy effects
between activated carbon injection and controls likely to be used to
meet the floor level. We estimate that this beyond-the-floor option
would increase the amount of hazardous waste \126\ generated by 3,300
tons per year and would also require sources to use an additional 1.2
million kW-hours per year. Based on these impacts and costs of
approximately $13 million per additional grams of dioxin/furan removed,
we are not proposing a beyond-the-floor standard based on activated
carbon injection.
---------------------------------------------------------------------------

\126\ To estimate the cost of a beyond-the-floor standard
conservatively, we assumed the solid waste generated would be
subject to regulation as hazardous waste. These costs are likely
over-estimated, however, because these residues are not likely to
fail the criteria for retaining the Bevill exclusion under 40 CFR 266.112.
---------------------------------------------------------------------------

For these reasons, we propose a floor standard for dioxin/furan for
existing sources of compliance with the proposed CO/HC emission
standard and compliance with the proposed DRE standard.\127\
---------------------------------------------------------------------------

\127\ We note that we propose to require solid fuel-fired
boilers (and liquid fuel-fired boilers that are not subject to a
numerical dioxin/furan standard) to conduct a one-time dioxin/furan
emission test to provide data to assist in developing both section
112(d)(6) standards and section 112(f) residual risk standards. See
discussion in Section XIV.B of the preamble.
---------------------------------------------------------------------------

3. What Is the Rationale for the MACT Floor for New Sources?
As discussed above, we propose to use the CO/HC and DRE standards
as surrogates to ensure good combustion conditions, and thus, control
of dioxin/furan emissions. Because we are proposing the same DRE and
CO/HC standards for existing sources and new sources as discussion in
Sections G and H below, we are proposing the same dioxin/furan floor
for new and existing sources.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We are not proposing beyond-the-floor standards for CO/HC for
dioxin/furan for new solid fuel-fired boilers because we are not
proposing beyond-the-floor standards for CO/HC and DRE

[[Page 21276]]

for new sources. See discussion in Sections G and H below.
In addition, we evaluated activated carbon injection or, for
sources equipped with baghouses, use of catalytically impregnated
fabric felt/membrane filter materials as beyond-the-floor control for
further reduction of dioxin/furan emissions to achieve a beyond-the-
floor level of 0.15 ng TEQ/dscm. The incremental annualized compliance
cost for a new solid fuel-fired boiler with average gas flowrate to
meet this beyond-the-floor level, rather than comply with the floor
level, would be approximately $0.28 million and would provide an
incremental reduction in dioxin/furan emissions of approximately 0.21
grams TEQ per year, for a cost-effectiveness of $1.3 million per gram
of dioxin/furan removed. We estimate that this beyond-the-floor option
would increase the amount of hazardous waste (or solid waste if the
source retains the Bevill exclusion under 40 CFR 266.112) generated for
a new solid fuel-fired boiler with average gas flowrate by 270 tons per
year and would require a source to use an additional 0.1 million kW-
hours per year beyond the requirements to achieve the floor level.
After considering these impacts and a cost of $1.3 million per gram of
dioxin/furan removed, we conclude that a beyond-the-floor standard
based on activated carbon injection or catalytically impregnated fabric
felt/membrane filter is not warranted for new sources. Consequently, we
propose a floor standard for dioxin/furan for new sources: Compliance
with the proposed CO/HC and DRE emissions standards.

B. What Is the Rationale for the Proposed Standards for Mercury?

The proposed standard for mercury for solid fuel-fired boilers is
10 [mu]g/dscm for both existing sources and new sources.\128\
---------------------------------------------------------------------------

\128\ As information, EPA proposed MACT standards for mercury
for solid fuel-fired industrial, commercial, and institutional
boilers that do not burn hazardous waste of 5.3 [mu]g/dscm for
existing sources and 3.4 [mu]g/dscm for new sources. See 68 FR 1660
(Jan. 13, 2003). These standards are based on use of fabric filters
to control mercury emissions.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
The MACT floor for existing sources is 10 [mu]g/dscm based on
adsorption of mercury onto coal fly ash and removal of fly ash by the
electrostatic precipitator or baghouse.
All solid fuel-fired boilers are equipped with electrostatic
precipitators or baghouses. We have compliance test emissions data for
three sources equipped with electrostatic precipitators which document
maximum mercury emissions ranging from 3 ug/dscm to 11 [mu]g/dscm and
system removal efficiencies of 83% to 96%. These three sources
represent seven of the 12 solid fuel-fired boilers.\129\ The Agency has
also determined that coal-fired utility boilers can achieve significant
control of mercury by adsorption on fly ash and particulate matter
control.\130\
---------------------------------------------------------------------------

\129\ Owners and operators have used the emissions data from the
three boilers as ``data in lieu of testing'' emissions from other,
identical boilers at the same facility. One of the three boilers as
two such sister identical boilers, and the other two boilers each
have a sister identical boiler. Thus, emissions from these three
boilers represent emissions from seven of the 12 solid fuel-fired boilers.
\130\ Memo from Frank Princiotta, USEPA, to John Seitz, USEPA,
entitled ``Control of Mercury Emissions from Coal-fired Utility
Boilers,'' dated October 25, 2000.
---------------------------------------------------------------------------

To identify the MACT floor, we evaluated the compliance test
emissions data using the SRE/Feed Approach. The calculated floor is 10
[mu]g/dscm, which considers emissions variability. This is an emission
level that the average of the best performing sources could be expected
to achieve in 99 of 100 future tests when operating under operating
conditions identical to the compliance test conditions during which the
emissions data were obtained. We estimate that this emission level is
being achieved by 67% of sources and would provide a reduction in
mercury emissions of 0.015 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of mercury: (1) Activated carbon injection; and (2) control of mercury
in the hazardous waste feed. For reasons discussed below, we are not
proposing a beyond-the-floor standard for mercury.
a. Use of Activated Carbon Injection. We evaluated activated carbon
injection as beyond-the-floor control for further reduction of mercury
emissions. Activated carbon has been demonstrated for controlling
mercury from waste combustion systems and has achieved efficiencies
ranging from 80% to greater than 90% depending on factors such as:
Activated carbon type/impregnation; injection rate; mercury speciation
in the flue gas; and flue gas temperature. We made a conservative
assumption that the use of activated carbon will provide 70% mercury
control for coal-fired boilers given the low mercury levels at the
floor. Applying this activated carbon removal efficiency to the mercury
floor level of 10 [mu]g/dscm would provide a beyond-the-floor level of
3.0 [mu]g/dscm.
The national incremental annualized compliance cost for solid fuel
boilers to meet this beyond-the-floor level rather than comply with the
floor controls would be approximately $1.1 million and would provide an
incremental reduction in mercury emissions beyond the MACT floor
controls of 0.03 tons per year. We evaluated nonair quality health and
environmental impacts and energy effects and estimate that this beyond-
the-floor option would increase the amount of hazardous waste (or solid
waste if the source retains the Bevill exclusion under 40 CFR 266.112)
generated by 1,000 tons per year and would require sources to use an
additional 0.35 million kW-hours per year beyond the requirements to
achieve the floor level. Based on these factors and costs of
approximately $35 million per additional ton of mercury removed, we are
not proposing a beyond-the-floor standard based on activated carbon
injection.
b. Feed Control of Mercury in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 8 [mu]g/dscm, which represents a
20% reduction from the floor level. The national incremental annualized
compliance cost for solid fuel boilers to meet this beyond-the-floor
level rather than comply with the floor controls would be approximately
$0.11 million and would provide an incremental reduction in mercury
emissions beyond the MACT floor controls of 0.005 tons per year. Nonair
quality health and environmental impacts and energy effects are not
significant factors for feedrate control.
We are not proposing a beyond-the-floor standard based on feed
control of mercury in the hazardous waste because it would not be cost-
effective at approximately $23 million per additional ton of mercury
removed. Consequently, we propose a floor standard for mercury for
existing sources of 10 [mu]g/dscm.
3. What Is the Rationale for MACT Floor for New Sources?
MACT floor for new sources would be 10 [mu]g/dscm, the same as the
floor for existing sources. This is an emission level that the single
best performing source identified by the SRE/Feed Approach could be
expected to achieve in 99 of 100 future tests when operating under
operating conditions identical to the compliance test conditions during
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We identified the same two potential beyond-the-floor techniques
for control

[[Page 21277]]

of mercury: (1) Use of activated carbon injection; and (2) control of
mercury in the hazardous waste feed.
We evaluated use of carbon injection for new sources to achieve a
beyond-the-floor emission level of 5.0 [mu]g/dscm. The incremental
annualized compliance cost for a new solid fuel boiler with average gas
flowrate to meet this beyond-the-floor level, rather than comply with
the floor level, would be approximately $0.28 million and would provide
an incremental reduction in mercury emissions of approximately 0.008
tons per year, for a cost-effectiveness of $37 million per ton of
mercury removed. We estimate that this beyond-the-floor option would
increase the amount of hazardous waste (or solid waste if the source
retains the Bevill exclusion under 40 CFR 266.112) generated for a new
solid fuel-fired boiler with average gas flowrate by 270 tons per year
and would require a source to use an additional 0.1 million kW-hours
per year beyond the requirements to achieve the floor level. After
considering these impacts and, primarily, cost-effectiveness, we are
not proposing a beyond-the-floor standard based on activated carbon
injection for new sources. Consequently, we propose a floor standard
for mercury of 10 [mu]g/dscm for new sources.

C. What Is the Rationale for the Proposed Standards for Particulate
Matter?

The proposed standards for particulate matter for solid fuel-fired
boilers are 69 mg/dscm (0.030 gr/dscf) for existing sources and 34 mg/
dscm (0.015 gr/dscf) for new sources.\131\ The particulate matter
standard serves as a surrogate for nonmercury HAP metals in emissions
from the coal burned in the boiler, and for nonenumerated HAP metal
emissions attributable to the hazardous waste fuel burned in the boiler.
---------------------------------------------------------------------------

\131\ As information, EPA proposed MACT standards for
particulate matter for solid fuel-fired industrial, commercial, and
institutional boilers that do not burn hazardous waste of 0.035 gr/
dscf for existing sources and 0.013 gr/dscf for new sources. See 68
FR 1660 (Jan. 13, 2003). These standards are based on control of
particulate matter emissions using a fabric filter.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
All solid fuel-fired boilers are equipped with electrostatic
precipitators or baghouses. We have compliance test emissions data for
seven boilers. Emissions from these seven boilers represent emissions
from all 12 solid fuel-fired boilers.\132\ Particulate emissions range
from 0.021 gr/dscf to 0.037 gr/dscf.\133\
---------------------------------------------------------------------------

\132\ Owners and operators have determined that emissions from
these seven boilers represent emissions from five other identical,
sister boilers. Owners and operators have used the emissions from
these seven boilers as ``data in lieu of testing'' emissions from
the other five identical boilers.
\133\ Although particulate matter emissions are predominantly
attributable to coal ash rather than ash from hazardous waste fuel,
we did not combine emissions data for coal-fired boilers that do not
burn hazardous waste with the data for boilers that burn hazardous
waste because we have particulate emissions data for all boilers
that burn hazardous waste.
---------------------------------------------------------------------------

To identify the floor level, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
air pollution control device approach. See discussion in Part Two,
Section VI.A.2.a. The calculated floor is 140 mg/dscm (0.063 gr/dscf),
which considers emissions variability. This is an emission level that
the average of the best performing sources could be expected to achieve
in 99 of 100 future tests when operating under conditions identical to
the compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 75%
of sources. Compliance with the floor level would reduce particulate
matter emissions by 33 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated improved design, operation, and maintenance of the
existing electrostatic precipitators (e.g., humidification to improve
gas conditioning) and baghouses (e.g., improved bags) for these boilers
to achieve a beyond-the-floor emission level of 69 mg/dscm (0.030 gr/
dscf). We also evaluated a more stringent standard based on adding a
polishing fabric filter to achieve a beyond-the-floor emission level of
0.015 gr/dscf. The national incremental annualized compliance cost for
solid fuel boilers to meet a beyond-the-floor level of 69 mg/dscm
rather than comply with the floor controls would be approximately $1.3
million and would provide an incremental reduction in particulate
matter emissions beyond the MACT floor controls of 400 tons per year
and an incremental reduction in metal HAP of 6.8 tons per year. We
evaluated nonair quality health and environmental impacts and energy
effects and estimate that this beyond-the-floor option would increase
the amount of hazardous waste (or solid waste if the source retains its
Bevill exclusion under 40 CFR 266.112) generated by 380 tons per year
and would require sources to use an additional 3.3 million kW-hours per
year and to use an additional 160 million gallons of water beyond the
requirements to achieve the floor level.
Notwithstanding these nonair quality health and environmental
impacts and energy effects, a beyond-the-floor standard of 69 mg/dscm
(0.030 gr/dscf) based on improved particulate matter control is
warranted because it is cost-effective at a cost of approximately
$3,200 per additional ton of particulate matter removed and a cost of
approximately $190,000 per additional ton of metal HAP removed.\134\ In
addition, the average incremental annualized cost would be only
$120,000 per facility. We also note that, although section 112(d) only
authorizes control of HAPs, and particulate matter is not itself a HAP
but a surrogate for HAP metals, Congress expected the MACT program to
result in significant emissions reductions of criteria air pollutants
(of which particulate matter is one), and viewed this as an important
benefit of the MACT (and residual risk) provisions. See 5 Legislative
History at 8512 (Senate Committee Report). Finally, we note that this
beyond-the-floor standard of 0.030 gr/dscf would be comparable to the
floor-based standard the Agency recently promulgated for solid fuel-
fired boilers that do not burn hazardous waste: 0.07 lb/MM Btu
(approximately 0.034 gr/dscf). See NESHAP for Industrial/Commercial/
Institutional Boilers and Process Heaters, signed Feb. 26, 2004.
Because hazardous waste does not contribute substantially to
particulate matter emissions from coal-fired boilers, MACT standards
for solid fuel boilers should be similar irrespective of whether they
burn hazardous waste.
---------------------------------------------------------------------------

\134\ Note that we are not proposing beyond-the-floor
particulate matter standards for incinerators, cement kilns,
lightweight aggregate kilns, and liquid fuel-fired boilers because
those standards would have a cost-effectiveness of $12,000 to
$80,000 per ton of particulate matter removed, substantially higher
than the $3,200 per ton cost-effectiveness of a beyond-the-floor
standard for solid fuel-fired boilers.
---------------------------------------------------------------------------

A 34 mg/dscm beyond-the-floor standard for existing sources based
on use of a polishing fabric filter would remove an additional 570 tons
per year of particulate matter beyond the floor level at a cost-
effectiveness of $9,800 per ton removed. We conclude that this standard
would not be as cost-effective as a 69 mg/dscm standard and would
result in greater nonair quality health and environmental impacts and
energy effects. For these reasons, we propose a beyond-the-floor
particulate matter standard of 0.030 gr/dscf (69 mg/dscm) for existing
sources. We specifically request comment on whether this beyond-the-
floor standard is warranted.

[[Page 21278]]

3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for new sources would be 90 mg/dscm (0.040 gr/dscf),
considering emissions variability. This is an emission level that the
single best performing source identified by the APCD Approach (i.e.,
the source using a fabric filter with the lowest emissions) could be
expected to achieve in 99 of 100 future tests when operating under
operating conditions identical to the compliance test conditions during
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated use of a fabric filter to achieve a beyond-the-floor
emission level of 34 mg/dscm (0.015 gr/dscf). The incremental
annualized cost for a new solid fuel-fired boiler with average gas
flowrate to meet this beyond-the-floor level, rather than comply with
the floor level, would be approximately $280,000 and would provide an
incremental reduction in particulate emissions of approximately 44 tons
per year, for a cost-effectiveness of $6,400 per ton of particulate
matter removed. We estimate that this beyond-the-floor option would
increase the amount of hazardous waste (or solid waste if the source
retains the Bevill exclusion under 40 CFR 266.112) generated for a new
solid fuel-fired boiler with average gas flowrate by 44 tons per year
and would require a source to use an additional 1.1 million kW-hours
per year beyond the requirements to achieve the floor level.
Notwithstanding these impacts, a standard of 34 mg/dscm (0.015 gr/dscf)
is warranted because it would be cost-effective and it would remove
additional nonenumerated metal HAP. We also note that this beyond-the-
floor standard of 0.015 gr/dscf for new sources would be comparable to
the floor-based standard the Agency recently promulgated for new solid
fuel-fired boilers that do not burn hazardous waste: 0.025 lb/MM Btu
(approximately 0.012 gr/dscf). See NESHAP for Industrial/Commercial/
Institutional Boilers and Process Heaters, signed Feb. 26, 2004.
For these reasons, we propose a beyond-the-floor particulate matter
standard of 34 mg/dscm (0.015 gr/dscf) for new sources. We specifically
request comment on whether this beyond-the-floor standard is warranted.

D. What Is the Rationale for the Proposed Standards for Semivolatile Metals?

The proposed standard for semivolatile metals (lead and cadmium,
combined) for solid fuel-fired boilers is 170 [mu]g/dscm for both
existing and new sources.\135\
---------------------------------------------------------------------------

\135\ As information, EPA proposed to control nonmercury metal
HAP emissions for industrial, commercial, and institutional boilers
that do not burn hazardous waste with a particulate matter emission
standard only. See 68 FR 1660 (Jan. 13, 2003). For hazardous waste
combustors, we propose to control specific, enumerated semivolatile
and low volatile metals with separate emission standards because
hazardous waste can have a wide range of concentrations of these
metals, and, thus, particulate matter may contain a wide range of
metal concentrations. Thus, particulate matter may not be an
effective surrogate for particular metal HAP. Nonetheless, for
practical reasons, we rely on particulate matter to control
nonenumerated metal HAP.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
We have compliance test emissions data for four boilers. Emissions
from these four boilers represent emissions from nine of the 12 solid
fuel-fired boilers.\136\ Semivolatile metal emissions range from 62
[mu]g/dscm to 170 [mu]g/dscm. These emissions are expressed as mass of
semivolatile metals (from all feedstocks) per unit of stack gas.
---------------------------------------------------------------------------

\136\ Owners and operators have determined that emissions from
these four boilers represent emissions from five other identical,
sister boilers. Owners and operators have used the emissions from
these four boilers as ``data in lieu of testing'' emissions from the
other five identical boilers.
---------------------------------------------------------------------------

To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 170 [mu]g/dscm, which
considers emissions variability. This is an emission level that the
average of the best performing sources could be expected to achieve in
99 of 100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this floor level is being achieved by 42% of
sources and would reduce semivolatile metals emissions by 0.22 tons per
year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated three beyond-the-floor approaches for semivolatile
metals for existing sources: (1) Improved control of particulate
matter; (2) control of semivolatile metals in the hazardous waste feed;
and (3) a no-cost standard derived from the beyond-the-floor
particulate matter standard. For reasons discussed below, we are not
proposing a beyond-the-floor standard for semivolatile metals.
a. Improved Particulate Matter Control. Controlling particulate
matter also controls emissions of semivolatile metals. Consequently, we
evaluated a beyond-the-floor level of 85 [mu]g/dscm, a 50 percent
reduction in semivolatile metal emissions, that would be achieved by
reducing particulate matter emissions. The national incremental
annualized compliance cost for solid fuel boilers to meet this beyond-
the-floor level rather than comply with the floor controls would be
approximately $0.29 million and would provide an incremental reduction
in semivolatile metals emissions beyond the MACT floor controls of 0.29
tons per year. We evaluated the nonair quality health and environmental
impacts and energy effects of this beyond-the-floor standard and
estimate that the amount of hazardous waste generated would increase by
approximately 133 tons per year, an additional 61 million gallons per
year of water would be used, and an additional 1.3 million kW-hours per
year of electricity would be used. Therefore, based on these factors
and costs of approximately $1 million per additional ton of
semivolatile metals removed, we are not proposing a beyond-the-floor
standard based on improved particulate matter control.
b. Feed Control of Semivolatile Metals in the Hazardous Waste. We
also evaluated a beyond-the-floor level of 140 [mu]g/dscm based on
additional control of semivolatile metals in the hazardous waste feed.
This represents a 20% reduction from the floor level. The national
incremental annualized compliance cost for solid fuel boilers to meet
this beyond-the-floor level rather than comply with the floor controls
would be approximately $36,000 and would provide an incremental
reduction in semivolatile metals emissions beyond the MACT floor
controls of 0.046 tons per year. Although nonair quality health and
environmental impacts and energy effects are not significant factors,
we are not proposing a beyond-the-floor standard based on feed control
of semivolatile metals in the hazardous waste because it is not cost-
effective at approximately $0.78 million per additional ton of
semivolatile metals removed.
c. No-cost Standard Derived from the Beyond-the-Floor Particulate
Matter Standard. The beyond-the-floor standard for particulate matter
would also provide beyond-the-floor control for semivolatile metals if
sources were to comply with the beyond-the-floor particulate matter
standard using improved particulate matter control

[[Page 21279]]

rather than by reducing the feedrate of ash. To identify a beyond-the-
floor emission level for semivolatile metals that would derive from the
beyond-the-floor particulate matter standard, we assumed that emissions
of semivolatile metals would be reduced by the same percentage that
sources would need to reduce particulate matter emissions. We then
developed a revised semivolatile metal emission data base considering
these particulate matter standard-derived reductions and reductions
needed to meet the semivolatile metal floor level. We analyzed these
revised emissions to identify the best performing sources and an
emission level that the average of the best performers could achieve 99
out of 100 future tests. This emission level--82 [mu]g/dscm--is a
beyond-the-floor semivolatile metal standard that can be achieved at no
cost because the costs have been allocated to the particulate matter
beyond-the-floor standard.
We are concerned, however, that sources may choose to comply with
the beyond-the-floor particulate matter standard by controlling the
feedrate of ash in the hazardous waste feed, which may or may not
reduce the feedrate and emissions of metal HAP. If so, it would be
inappropriate to consider the beyond-the-floor standard for
semivolatile metals discussed above as a no-cost standard. We
specifically request comment on whether sources may comply with beyond-
the-floor particulate matter standard by controlling the feedrate of ash.
For these reasons, we propose a floor standard for semivolatile
metals of 170 [mu]g/dscm for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for new sources would be 170 [mu]g/dscm, considering
emissions variability. This is the same as the floor for existing
sources. This is an emission level that the single best performing
source identified by the SRE/Feed Approach could be expected to achieve
in 99 of 100 future tests when operating under operating conditions
identical to the compliance test conditions during which the emissions
data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated three beyond-the-floor approaches for semivolatile
metals for new sources: (1) Improved particulate matter controls; (2)
control of semivolatile metals in the hazardous waste feed; and (3) a
no-cost standard derived from the beyond-the-floor particulate matter
standard.
a. Improved Particulate Matter Controls. We evaluated improved
control of particulate matter using a fabric filter as beyond-the-floor
control for further reductions in semivolatile metals emissions. We
evaluated a beyond-the-floor level of 71 [mu]g/dscm. The incremental
annualized compliance cost for a new solid fuel boiler with average gas
flowrate to meet this beyond-the-floor level, rather than comply with
the floor level, would be approximately $0.28 million and would provide
an incremental reduction in semivolatile metals emissions of
approximately 0.15 tons per year, for a cost-effectiveness of $1.8
million per ton of semivolatile metals removed. We estimate that this
beyond-the-floor option would increase the amount of hazardous waste
(or solid waste if the source retains the Bevill exclusion under 40 CFR
266.112) generated for a new solid fuel-fired boiler with average gas
flowrate by 44 tons per year and would require the source to use an
additional 1.2 million kW-hours per year beyond the requirements to
achieve the floor level. After considering these impacts and cost-
effectiveness, we conclude that a beyond-the-floor standard for new
sources based on use of a fabric filter to improve control of
particulate matter is not warranted.
b. Feedrate Control. For similar reasons discussed above for
existing sources, we conclude that a beyond-the-floor standard based on
controlling the semivolatile metals in the hazardous waste feed would
not be cost-effective.
c. No-cost Standard Derived from the Beyond-the-Floor Particulate
Matter Standard. As discussed above in the context of existing sources,
the beyond-the-floor standard for particulate matter would also provide
beyond-the-floor control for semivolatile metals if sources were to
comply with the beyond-the-floor particulate matter standard using
improved particulate matter control rather than by reducing the
feedrate of ash. Under this approach, the no-cost beyond-the-floor
standard for semivolatile metals for new sources would be 44 [mu]g/
dscm. As discussed above, however, we are concerned that sources may
choose to comply with the beyond-the-floor particulate matter standard
by controlling the feedrate of ash in the hazardous waste feed, which
may or may not reduce the feedrate and emissions of metal HAP. If so,
it would be inappropriate to consider this beyond-the-floor standard as
a no-cost standard. We specifically request comment on whether sources
may comply with beyond-the-floor particulate matter standard by
controlling the feedrate of ash.
For these reasons, we propose a semivolatile metals standard of 170
[mu]g/dscm for new sources.

E. What Is the Rationale for the Proposed Standards for Low Volatile Metals?

The proposed standards for low volatile metals (arsenic, beryllium,
and chromium) for solid fuel-fired boilers is 210 [mu]g/dscm for
existing sources and 190 [mu]g/dscm for new sources.
1. What Is the Rationale for the MACT Floor for Existing Sources?
We have compliance test emissions data for four boilers. Emissions
from these four boilers represent emissions from 10 of the 12 solid
fuel-fired boilers.\137\ Low volatile metal emissions range from 41
[mu]g/dscm to 230 [mu]g/dscm. These emissions are expressed as mass of
low volatile metals (from all feedstocks) per unit of stack gas.
---------------------------------------------------------------------------

\137\ Owners and operators have determined that emissions from
these four boilers represent emissions from five other identical,
sister boilers. Owners and operators have used the emissions from
these four boilers as ``data in lieu of testing'' emissions from the
other five identical boilers.
---------------------------------------------------------------------------

To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 210 [mu]g/dscm, which
considers emissions variability. This is an emission level that the
average of the best performing sources could be expected to achieve in
99 of 100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 67%
of sources and that it would reduce low volatile metals emissions by
0.45 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated three beyond-the-floor approaches for low volatile
metals for existing sources: (1) Improved control of particulate
matter; (2) control of low volatile metals in the hazardous waste feed;
and (3) a no-cost standard derived from the beyond-the-floor
particulate matter standard. For reasons discussed below, we are not
proposing a beyond-the-floor standard for low volatile metals.
a. Improved Particulate Matter Control. Controlling particulate
matter also controls emissions of low volatile metals. We evaluated a
beyond-the-floor level of 105 [mu]g/dscm. The national incremental
annualized compliance cost for solid fuel boilers to meet this

[[Page 21280]]

beyond-the-floor level rather than comply with the floor controls would
be approximately $0.32 million and would provide an incremental
reduction in low volatile metals emissions beyond the MACT floor
controls of 0.37 tons per year. We evaluated the nonair quality health
and environmental impacts and energy effects of this beyond-the-floor
standard and estimate that the amount of hazardous waste generated
would increase by approximately 83 tons per year, an additional 54
million gallons of water per year would be used, and electricity
consumption would increase by 1.2 million kW-hours per year.
Considering these impacts and a cost of approximately $0.87 million per
additional ton of low volatile metals removed, we are not proposing a
beyond-the-floor standard based on improved particulate matter control.
b. Feed Control of Low Volatile Metals in the Hazardous Waste. We
also evaluated a beyond-the-floor level of 170 [mu]g/dscm, which
represents a 20% reduction from the floor level. The national
incremental annualized compliance cost for solid fuel boilers to meet
this beyond-the-floor level rather than comply with the floor controls
would be approximately $98,000 and would provide an incremental
reduction in low volatile metals emissions beyond the MACT floor
controls of 0.13 tons per year. Although nonair quality health and
environmental impacts and energy effects are not significant factors,
we are not proposing a beyond-the-floor standard based on feedrate
control of low volatile metals in the hazardous waste because it would
not be cost-effective at approximately $0.78 million per additional ton
of low volatile metals removed.
c. No-cost Standard Derived from the Beyond-the-Floor Particulate
Matter Standard. As discussed above in the context of semivolatile
metals, the beyond-the-floor standard for particulate matter would also
provide beyond-the-floor control for low volatile metals if sources
were to comply with the beyond-the-floor particulate matter standard
using improved particulate matter control rather than by reducing the
feedrate of ash. To identify a beyond-the-floor emission level for low
volatile metals that would derive from the beyond-the-floor particulate
matter standard, we assumed that emissions of low volatile metals would
be reduced by the same percentage that sources would need to reduce
particulate matter emissions. We then developed a revised low volatile
metal emission data base considering these particulate matter standard-
derived reductions and reductions needed to meet the low volatile metal
floor level. We analyzed these revised emissions to identify the best
performing sources and an emission level that the average of the best
performers could achieve 99 out of 100 future tests. This emission
level--110 [mu]g/dscm--is a beyond-the-floor low volatile metal
standard that can be achieved at no cost because the costs have been
allocated to the particulate matter beyond-the-floor standard.
We are concerned, however, that sources may choose to comply with
the beyond-the-floor particulate matter standard by controlling the
feedrate of ash in the hazardous waste feed, which may or may not
reduce the feedrate and emissions of metal HAP. If so, it would be
inappropriate to consider the beyond-the-floor standard for low
volatile metals discussed above as a no-cost standard. We specifically
request comment on whether sources may comply with beyond-the-floor
particulate matter standard by controlling the feedrate of ash.
For these reasons, we propose a floor standard for low volatile
metals of 210 [mu]g/dscm for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for low volatile metals for new sources would be 190
[mu]g/dscm, considering emissions variability. This is an emission
level that the single best performing source identified by the SRE/Feed
Approach could be expected to achieve in 99 of 100 future tests when
operating under operating conditions identical to the compliance test
conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated three beyond-the-floor approaches for low volatile
metals for new sources: (1) Improved particulate matter control; (2)
control of low volatile metals in the hazardous waste feed; and (3) a
no-cost standard derived from the beyond-the-floor particulate matter
standard.
a. Improved Particulate Matter Control. We evaluated improved
control of particulate matter using a fabric filter to achieve an
emission level of 79 [mu]g/dscm as beyond-the-floor control for low
volatile metals emissions. The incremental annualized compliance cost
for a new solid fuel boiler to meet this beyond-the-floor level, rather
than comply with the floor level, would be approximately $0.28 million
and would provide an incremental reduction in low volatile metals
emissions of approximately 0.17 tons per year, for a cost-effectiveness
of $1.7 million per ton of low volatile metals removed. We estimate
that this beyond-the-floor option would increase the amount of
hazardous waste (or solid waste if the source retains the Bevill
exclusion under 40 CFR 266.112) generated for a new solid fuel-fired
boiler with average gas flowrate by 44 tons per year and would require
the source to use an additional 1.2 million kW-hours per year beyond
the requirements to achieve the floor level. After considering these
impacts and cost-effectiveness, we conclude that a beyond-the-floor
standard based on improved particulate matter control using a fabric
filter for new sources is not warranted.
b. Feedrate Control. For similar reasons discussed above for
existing sources, we conclude that a beyond-the-floor standard based on
controlling the low volatile metals in the hazardous waste feed would
not be cost-effective.
c. No-cost Standard Derived from the Beyond-the-Floor Particulate
Matter Standard. As discussed above in the context of existing sources,
the beyond-the-floor standard for particulate matter would also provide
beyond-the-floor control for low volatile metals if sources were to
comply with the beyond-the-floor particulate matter standard using
improved particulate matter control rather than by reducing the
feedrate of ash. Under this approach, the no-cost beyond-the-floor
standard for low volatile metals for new sources would be 34 [mu]g/
dscm. As discussed above, however, we are concerned that sources may
choose to comply with the beyond-the-floor particulate matter standard
by controlling the feedrate of ash in the hazardous waste feed, which
may or may not reduce the feedrate and emissions of metal HAP. If so,
it would be inappropriate to consider this beyond-the-floor standard as
a no-cost standard. We specifically request comment on whether sources
may comply with beyond-the-floor particulate matter standard by
controlling the feedrate of ash.
For these reasons, we propose a low volatile metals standard of 190
[mu]g/dscm for new sources.

F. What Is the Rationale for the Proposed Standards for Total Chlorine?

The proposed standards for hydrogen chloride and chlorine gas
(i.e., total chlorine, reported as a hydrogen chloride equivalents) for
solid fuel-fired boilers are 440 ppmv for existing sources and 73 ppmv
for new sources.\138\
---------------------------------------------------------------------------

\138\ As information, EPA proposed MACT standards for hydrogen
chloride for solid fuel-fired industrial, commercial, and
institutional boilers that do not burn hazardous waste of 68 ppmv
for existing sources and 15 ppmv for new sources. See 68 FR 1660
(Jan. 13, 2003). These standards are based on use of wet scrubbers
to control hydrogen chloride.

---------------------------------------------------------------------------

[[Page 21281]]

1. What Is the Rationale for the MACT Floor for Existing Sources?
Solid fuel-fired boilers that burn hazardous waste are equipped
with electrostatic precipitators or baghouses and do not have back-end
controls for total chlorine. Total chlorine emissions are controlled by
controlling the feedrate of chlorine in the hazardous waste feed. We
have compliance test emissions data for five boilers. Emissions from
these five boilers represent emissions from 10 of the 12 solid fuel-
fired boilers.\139\ Total chlorine emissions range from 60 ppmv to 700 ppmv.
---------------------------------------------------------------------------

\139\ Owners and operators have determined that emissions from
these five boilers represent emissions from five other identical,
sister boilers. Owners and operators have used the emissions from
these five boilers as ``data in lieu of testing'' emissions from the
other five identical boilers.
---------------------------------------------------------------------------

To identify the MACT floor, we evaluated the compliance test
emissions data associated with the most recent test campaign using the
SRE/Feed Approach. The calculated floor is 440 ppmv, which considers
emissions variability. This is an emission level that the best
performing feed control sources could be expected to achieve in 99 of
100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this emission level is being achieved by 83%
of sources and that it would reduce total chlorine emissions by 420
tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated dry scrubbing to achieve a beyond-the-floor emission
level of 110 ppmv for total chlorine for existing sources, assuming
conservatively a 75% removal efficiency. The national annualized
incremental compliance cost for solid fuel-fired boilers to comply with
this beyond-the-floor level rather than the floor level would be $3.7
million, and emissions of total chlorine would be reduced by an
additional 790 tons per year, for a cost-effectiveness of $4,700 per
ton of total chlorine removed. We evaluated the nonair quality health
and environmental impacts and energy effects of this beyond-the-floor
level and estimate that the amount of hazardous waste generated would
increase by 18,000 tons per year, an additional 27 million gallons of
water per year would be used, and electricity consumption would
increase by 0.11 million kW-hours per year.
We note that a cost of $4,700 per additional ton of total chlorine
removed is in the ``grey area'' between a cost the Agency has concluded
is cost-effective and a cost the Agency has concluded is not cost-
effective under other MACT rules. EPA concluded that a cost of $1,100
per ton of total chlorine removed for hazardous waste burning
lightweight aggregate kilns was cost-effective in the 1999 MACT final
rule. See 68 FR at 52900. EPA concluded, however, that a cost of
$45,000 per ton of hydrogen chloride removed was not cost-effective for
industrial boilers. See 68 FR at 1677.
Although a beyond-the-floor standard of 110 ppmv for solid fuel
boilers under today's rule would provide health benefits from
collateral reductions in SO2 emissions,\140\ we are
concerned that a cost of $4,700 per additional ton of total chlorine
removed is not warranted. Therefore, after considering cost-
effectiveness and nonair quality health and environmental impacts and
energy effects, we are not proposing a beyond-the-floor standard based
on dry scrubbing. We specifically request comment on whether a beyond-
the-floor standard is warranted.
---------------------------------------------------------------------------

\140\ See U.S. EPA, ``Addendum to the Assessment of the
Potential Costs, Benefits, and Other Impacts of the Hazardous Waste
Combustion MACT Replacement Standards--Proposed Rule,'' March 2004.
---------------------------------------------------------------------------

We also evaluated use of feedrate control of chlorine in hazardous
waste to achieve a beyond-the-floor level of 350 ppmv, which represents
a 20% reduction from the floor level. The national annualized
incremental compliance cost for solid fuel-fired boilers to comply with
this beyond-the-floor level rather than the floor level would be $0.08
million, and emissions of total chlorine would be reduced by an
additional 40 tons per year, for a cost-effectiveness of $2,000 per ton
of total chlorine removed. Although nonair quality health and
environmental impacts and energy effects are not significant factors
for feedrate control, we are not proposing a beyond-the-floor standard
based on hazardous waste feedrate control because we are concerned
about the practicability of achieving these emissions reductions, and
our estimate of the associated cost, using feedrate control. We
specifically request comment on use of feedrate control of chlorine in
hazardous waste as a beyond-the-floor control technique, the emission
reductions that could be achieved, and the costs of achieving those
reductions.
3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for new sources would be 73 ppmv. This is an emission
level that the single best performing source identified by the
Emissions Approach (i.e., the source with the lowest emissions) could
be expected to achieve in 99 of 100 future tests when operating under
operating conditions identical to the compliance test conditions during
which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated dry lime scrubbing to achieve a beyond-the-floor
emission level of 37 ppmv for total chlorine for new sources, assuming
conservatively a 50% removal efficiency.\141\ The incremental
annualized compliance cost for a new solid fuel boiler with average gas
flowrate to meet this beyond-the-floor level, rather than comply with
the floor level, would be approximately $610,000 and would provide an
incremental reduction in total chlorine emissions of approximately 42
tons per year. Although nonair quality health and environmental impacts
and energy effects are not significant factors, we conclude that a
beyond-the-floor standard of 37 ppmv is not warranted because it would
not be cost-effective at approximately $14,000 per additional ton of
total chlorine removed.
---------------------------------------------------------------------------

\141\ Although we assumed dry scrubbing can readily achieve 75%
removal of total chlorine for beyond-the-floor control for existing
sources, assuming 50% removal for beyond-the-floor control for new
sources is appropriate. This is because the floor for new sources--
73 ppmv--is substantially lower than the floor for existing
sources--440 ppmv--and dry scrubbing is less efficient at lower
uncontrolled emission levels.
---------------------------------------------------------------------------

For these reasons, we propose a floor standard for total chlorine
of 73 ppmv for new sources.

G. What Is the Rationale for the Proposed Standards for Carbon Monoxide
or Hydrocarbons?

To control emissions of organic HAP, existing and new sources would
be required to comply with either a carbon monoxide standard of 100
ppmv or a hydrocarbon standard of 10 ppmv.\142\
---------------------------------------------------------------------------

\142\ As information, EPA proposed MACT standards for carbon
monoxide for new solid fuel-fired industrial, commercial, and
institutional boilers that do not burn hazardous waste of 400 ppmv
corrected to 3% oxygen. See 68 FR 1660 (Jan. 13, 2003).
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
Solid fuel-fired boilers that burn hazardous waste are currently
subject to RCRA standards that require

[[Page 21282]]

compliance with either a carbon monoxide standard of 100 ppmv, or a
hydrocarbon standard of 20 ppmv. Compliance is based on an hourly
rolling average as measured with a CEMS. See Sec. 266.104(a). We are
proposing today floor standards of 100 ppmv for carbon monoxide or 10
ppmv for hydrocarbons.
Floor control for existing sources is operating under good
combustion practices including: (1) Providing adequate excess air with
use of oxygen CEMS and feedback air input control; (2) providing
adequate fuel/air mixing; (3) homogenizing hazardous waste fuels (such
as by blending or size reduction) to control combustion upsets due to
very high or very low volatile content wastes; (4) regulating waste and
air feedrates to ensure proper combustion temperature and residence
time; (5) characterizing waste prior to burning for combustion-related
composition (including parameters such as heating value, volatile
content, liquid waste viscosity, etc.); (6) ensuring the source is
operated by qualified, experienced operators; and (7) periodic
inspection and maintenance of combustion system components such as
burners, fuel and air supply lines, injection nozzles, etc. Given that
there are many interdependent parameters that affect combustion
efficiency and thus carbon monoxide and hydrocarbon emissions, we are
not able to quantify ``good combustion practices.''
Ten of 12 solid fuel-fired boilers are currently complying with the
RCRA carbon monoxide limit of 100 ppmv on an hourly rolling average.
The remaining two boilers are complying with the RCRA hydrocarbon limit
of 20 ppmv on an hourly rolling average. Those boilers have hydrocarbon
levels below 5 ppmv, however, indicative of operating under good
combustion practices.
We propose a floor level for carbon monoxide level of 100 ppmv
because it is a currently enforceable Federal standard. Although the
best performing sources are achieving carbon monoxide levels below 100
ppmv, it is not appropriate to establish a lower floor level because
carbon monoxide is a surrogate for nondioxin/furan organic HAP. As
such, lowering the carbon monoxide floor may not significantly reduce
organic HAP emissions. In addition, it would be inappropriate to apply
a MACT methodology to the carbon monoxide emissions from the best
performing sources because those sources may not be able to replicate
their emission levels. This is because there are myriad factors that
affect combustion efficiency and, subsequently, carbon monoxide
emissions. Extremely low carbon monoxide emissions cannot be assured by
controlling only one or two operating parameters We note also that we
used this rationale to establish a carbon monoxide standard of 100 ppmv
for Phase I sources in the September 1999 Final Rule.
We propose a floor level for hydrocarbons of 10 ppmv even though
the currently enforceable standard is 20 ppmv because: (1) The two
sources that comply with the RCRA hydrocarbon standard can readily
achieve 10 ppmv; and (2) reducing hydrocarbon emissions within the
range of 20 ppmv to 10 ppmv should reduce emissions of nondioxin/furan
organic HAP. We do not apply a prescriptive MACT methodology to
establish a hydrocarbon floor below 10 ppmv, however, because we have
data from only two sources. In addition, we note that the hydrocarbon
emission standard for Phase I sources established in the September 1999
Final Rule is 10 ppmv also.
There would be no incremental emission reductions associated with
these floors because all sources are currently achieving the floor levels.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We considered beyond-the-floor levels for carbon monoxide and
hydrocarbons based on use of better combustion practices but conclude
that they may not be replicable by the best performing sources nor
duplicable by other sources given that we cannot quantify good
combustion practices. Moreover, we cannot ensure that carbon monoxide
or hydrocarbon levels lower than the floors would significantly reduce
emissions of nondioxin/furan organic HAP. This is because the portion
of hydrocarbons that is comprised of nondioxin/furan organic HAP is
likely to become lower as combustion efficiency improves and
hydrocarbon levels decrease. Thus, at beyond-the-floor hydrocarbon
levels, we would expect a larger portion of residual hydrocarbons to be
compounds that are not organic HAP.
Nonair quality health and environmental impacts and energy
requirements are not significant factors for use of better combustion
practices as beyond-the-floor control.
For these reasons, we conclude that beyond-the-floor standards for
carbon monoxide and hydrocarbons are not warranted for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for new sources would be the same as the floor for
existing sources--100 ppmv for carbon monoxide and 10 ppmv for
hydrocarbons--and based on the same rationale.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
As discussed in the context of beyond-the-floor considerations for
existing sources, we considered beyond-the-floor standards for carbon
monoxide and hydrocarbons for new sources based on use of better
combustion practices. But, we conclude that beyond the floor standards
may not be replicable by the best performing sources nor duplicable by
other sources given that we cannot quantify good combustion practices.
Moreover, we cannot ensure that carbon monoxide or hydrocarbon levels
lower than the floors would significantly reduce emissions of
nondioxin/furan organic HAP.
Nonair quality health and environmental impacts and energy
requirements are not significant factors for use of better combustion
practices as beyond-the-floor control.
For these reasons, we conclude that beyond-the-floor standards for
carbon monoxide and hydrocarbons are not warranted for new sources.

H. What Is the Rationale for the Proposed Standard for Destruction and
Removal Efficiency?

[[Page 21283]]

We propose to establish the RCRA DRE standard as the floor for
existing sources because it is a currently enforceable Federal
standard. There would be no incremental emission reductions associated
with this floor because sources are currently complying with the standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We considered a beyond-the-floor level for DRE based on use of
better combustion practices but conclude that it may not be replicable
by the best performing sources nor duplicable by other sources given
that we cannot quantify better combustion practices. Moreover, we
cannot ensure that a higher DRE standard would significantly reduce
emissions of organic HAP given that DRE measures the destruction of
organic HAP present in the boiler feed rather than gross emissions of
organic HAP. Although a source's combustion practices may be adequate
to destroy particular organic HAP in the feed, other organic HAP that
may be emitted as products of incomplete combustion may not be
controlled by the DRE standard.\143\
---------------------------------------------------------------------------

\143\ The carbon monoxide/hydrocarbon emission standard would
control organic HAP that are products of incomplete combustion by
also ensuring use of good combustion practices.
---------------------------------------------------------------------------

For these reasons, and after considering non-air quality health and
environmental impacts and energy requirements, we are not proposing a
beyond-the-floor DRE standard for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
We propose to establish the RCRA DRE standard as the floor for new
sources because it is a currently enforceable Federal standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
Using the same rationale as we used to consider a beyond-the-floor
DRE standard for existing sources, we conclude that a beyond-the-floor
DRE standard for new sources is not warranted. Consequently, after
considering non-air quality health and environmental impacts and energy
requirements, we are proposing the floor DRE standard for new sources.

XI. How Did EPA Determine the Proposed Emission Standards for Hazardous
Waste Burning Liquid Fuel-Fired Boilers?

The proposed standards for existing and new liquid fuel-fired
boilers that burn hazardous waste are summarized in the table below.
See proposed Sec. 63.1217.

Proposed Standards for Existing and New Liquid Fuel-Fired Boilers
------------------------------------------------------------------------
Emission standard \1\
Hazardous air pollutant or ---------------------------------------
surrogate Existing sources New sources
------------------------------------------------------------------------
Dioxin and furan: sources 0.40 ng TEQ/dscm.. 0.015 ng TEQ/dscm
equipped with dry air pollution or control of
control system \2\. flue gas
temperature not
to exceed
400[deg]F at the
inlet to the
particulate
matter control
device.
Dioxin and furan: sources 100 ppmv carbon 100 ppmv carbon
equipped with wet or with no monoxide or 10 monoxide or 10
air pollution control systems ppmv hydrocarbons. ppmv hydrocarbons
\2\.
Mercury \3\..................... 3.7E-6 lbs/MM Btu. 3.8E-7 lbs/MM BTU
Particulate matter.............. 72 mg/dscm (0.032 17 mg/dscm (0.0076
gr/dscf). gr/dscf)
Semivolatile metals \3\......... 1.1E-5 lbs/MM BTU. 4.3E-6 lbs/MM BTU
Low volatile metals: chromium 1.1E-4 lbs/MM BTU. 3.6E-5 lbs/MM BTU
only 3, 4.
Hydrogen chloride and chlorine 2.5E-2 lbs/MM BTU 7.2E-4 lbs/MM BTU
gas3, 5. or the or the chlorine
alternative alternative
emission limits emission limits
under Sec. under Sec.
63.1215. 63.1215
Carbon monoxide or hydrocarbons 100 ppmv carbon 100 ppmv carbon
\6\. monoxide or 10 monoxide or 10
ppmv ppmv
hydrocarbons.. hydrocarbons.
Destruction and Removal For existing and new sources, 99.99%
Efficiency. for each principal organic hazardous
constituent (POHC). For sources
burning hazardous wastes F020, F021,
F022, F023, F026, or F027, however,
99.9999% for each POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ A wet air pollution system followed by a dry air pollution control
system is not considered to be a dry air pollution control system for
purposes of this standard. A dry air pollution systems followed a wet
air pollution control system is considered to be a dry air pollution
control system for purposes of this standard.
\3\ Standards are expressed as mass of pollutant emissions contributed
by hazardous waste per million Btu contributed by the hazardous waste.

\4\ Standard is for chromium only and does not include arsenic and beryllium.
\5\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\6\ Hourly rolling average. Hydrocarbons reported as propane.

We considered whether fuel switching could be considered a MACT
floor control technology for liquid fuel-fired boilers to achieve lower
HAP emissions. We conclude that HAP emissions from liquid fuel-fired
boilers are attributable primarily to the hazardous waste fuels rather
than the natural gas or fuel oil that these boilers burn. Consequently,
we conclude that fuel switching is not an effective MACT floor control
technology to reduce HAP emissions for liquid fuel-fired boilers.

A. What Are the Proposed Standards for Dioxin and Furan?

We propose to establish a dioxin/furan standard for existing liquid
fuel-fired boilers equipped with dry air pollution control devices of
0.40 ng TEQ/dscm. The standard for new sources would be 0.015 ng TEQ/
dscm or control of flue gas temperature not to exceed 400 [deg]F at the
inlet to the particulate matter control device. For liquid fuel-fired
boilers equipped either with wet air pollution control systems or with
no air pollution systems, we propose a standard for both existing and
new sources as compliance with the proposed standards for carbon
monoxide/hydrocarbon and destruction and removal efficiency. In
addition, we note that we propose to require a one-time dioxin/furan
emission test for

[[Page 21284]]

sources that would not be subject to a numerical dioxin/furan emission
standard, including liquid fuel-fired boilers with wet or no emission
control device, and new liquid fuel-fired boilers equipped with a dry
air pollution control device. As discussed in Part Two, Section XIV.B
below, the testing would assist in developing both section 112(d)(6)
standards and section 112(f) residual risk standards.
1. What Is the Rationale for the MACT Floor for Existing Sources?
As discussed in Part Two, Section I.B.5, we used a statistical
analysis to conclude that liquid boilers equipped with dry air
pollution control devices have different dioxin/furan emission
characteristics compared to sources with either wet air pollution
control or no air pollution control devices.\144\ Note that we consider
the type of emission control device as a basis for subcategorization
because the type of control device affects formation of dioxin/furan:
dioxin/furan can form in dry particulate matter control devices while
it cannot form in wet (or no) control devices. We therefore believe
subcategorization is warranted and we propose to identify separate
floor levels for sources equipped with dry particulate matter control
devices versus sources with wet or no emission control device.
---------------------------------------------------------------------------

\144\ Sources with a wet air pollution system followed by a dry
air pollution control system is not considered to be a dry air
pollution control system for purposes of this standard. Sources with
a dry air pollution systems followed a wet air pollution control
system is considered to be a dry air pollution control system for
purposes of this standard.
---------------------------------------------------------------------------

a. MACT Floor for Boilers Equipped with Dry Control Systems. To
identify the floor level for liquid fuel boilers equipped with dry air
pollution control systems, we considered whether dioxin/furan can be
controlled by controlling the temperature at the inlet to the
particulate matter control device. We conclude that this control
mechanism may not be the predominant factor that affects dioxin/furan
emissions from these sources. We have emissions data for three boilers
equipped with electrostatic precipitators or fabric filters. Emissions
from two of the boilers are below 0.03 ng TEQ/dscm. We do not have data
on the gas temperature at the inlet to the emission control device for
these sources. The third boiler, however, has dioxin/furan emissions of
2.4 ng TEQ/dscm when the flue gas temperature at the inlet to the
fabric filter is 410 [deg]F. We conclude from this information that
this boiler is not likely to be able to achieve dioxin/furan emissions
below 0.40 ng TEQ/dscm if the gas temperature is reduced to below 400
[deg]F. This is contrary to the finding we made for cement kilns and
incinerators without heat recovery boilers and equipped with dry
particulate matter control devices. In those cases, we conclude that
gas temperature control at the dry particulate matter control device is
the predominant factor affecting dioxin/furan emissions. See
discussions in Sections VII and VIII above. Consequently, other factors
are likely contributing to high dioxin/furan emissions from the liquid
fuel-fired boiler equipped with a fabric filter operated at a gas
temperature of 410 [deg]F, such as metals in the waste feed or soot on
boiler tubes that may catalyze dioxin/furan formation reactions.
We evaluated the compliance test emissions data using the Emissions
Approach and calculated a numerical dioxin/furan floor level of 3.0 ng
TEQ/dscm, which considers emissions variability. As discussed above,
however, one of the three sources for which we have emissions data is
not likely to be able to achieve this emission level using gas
temperature control at the inlet to the dry particulate matter control
device. Consequently, we propose to identify the floor level as 3.0 ng
TEQ/dscm or control of flue gas temperature not to exceed 400 [deg]F at
the inlet to the particulate matter control device. This floor level is
duplicable by all sources, and would minimize dioxin/furan emissions
for sources where flue gas temperature at the control device
substantially affects dioxin/furan emissions. We estimate that this
emission level is being achieved by all sources and, thus, would not
reduce dioxin/furan emissions.
b. MACT Floor for Boilers Equipped with Wet or No Control Systems.
We have dioxin/furan emissions data for 33 liquid fuel-fired boilers
equipped with a wet or no particulate matter control device. Emissions
levels are below 0.1 ng TEQ/dscm for 30 of the sources. Emission levels
for the other three sources are 0.19, 0.36, and 0.44 ng TEQ/dscm.
As previously discussed in Part Two, Section VII.A, we believe that
it would be inappropriate to establish a numerical dioxin/furan
emission floor level for sources using wet or no air pollution control
systems based on the emissions achieved by the best performing sources
because a numerical floor level would not be replicable by the best
performing sources nor duplicable by other sources. As a result, we
propose to define the MACT floor for sources with wet or no emission
control devices as operating under good combustion practices by
complying with the destruction and removal efficiency and carbon
monoxide/hydrocarbon standards.\145\ There would be no emissions
reductions for these existing boilers to comply with the floor level
because they are currently complying with the carbon monoxide/
hydrocarbon standard and destruction and removal efficiency standard
pursuant to RCRA requirements.
---------------------------------------------------------------------------

\145\ The fact that we determined floor control for existing
sources as good combustion practices does not mean that all sources
using floor control will have low dioxin/furan emissions. As
discussed in Part Two, Section XIV.B., we are proposing to require
liquid fuel-fired boilers that would not be subject to a numerical
dioxin/furan emission standard to perform a one-time dioxin/furan
emissions test to quantify the effectiveness of today's proposed
surrogate for dioxin/furan emission control.
---------------------------------------------------------------------------

We also request comment on an alternative MACT floor expressed as a
dioxin/furan emission concentration for liquid fuel boilers with wet or
no emission control devices.\146\ Although it would be inappropriate to
identify a floor concentration based on the average emissions of the
best performing sources as discussed above, we possibly could identify
the floor as the highest emission concentration from any source in our
data base, after considering emissions variability.
---------------------------------------------------------------------------

\146\ Although the floor for liquid fuel boilers equipped with a
dry emission control device would not be a numerical standard (i.e.,
3.0 ng TEQ/dscm or control of temperature of flue gas at the inlet
to the control device to 400 [deg]F), we propose a numerical beyond-
the-floor standard for those boilers, as discussed below in the
text.
---------------------------------------------------------------------------

2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated use of activated carbon injection systems or carbon
beds as beyond-the-floor control for further reduction of dioxin/furan
emissions. Activated carbon has been demonstrated for controlling
dioxin/furans in various combustion applications.
a. Beyond-the-Floor Considerations for Boilers Equipped with Dry
Control Systems. For liquid fuel-fired boilers using dry air pollution
control equipment, we evaluated a beyond-the-floor level of 0.40 ng
TEQ/dscm based on activated carbon injection or control of flue gas
temperature not to exceed 400 [deg]F at the inlet to the particulate
matter control device. The national incremental annualized compliance
cost for sources to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $80,000 and would
provide an incremental reduction in dioxin/furan emissions beyond the
MACT floor

[[Page 21285]]

controls of 0.06 grams TEQ per year for a cost-effectiveness of $1.3
million per additional gram of dioxin/furan removed. We evaluated the
nonair quality health and environmental impacts and energy effects of
this beyond-the-floor standard and estimate that the amount of
hazardous waste generated would increase by 100 tons per year, an
additional 25 trillion Btu per year of natural gas would be consumed,
and electricity consumption would increase by 0.50 million kW-hours per
year.
We judge that the cost to achieve this beyond-the-floor level is
warranted given our special concern about dioxin/furan. Dioxin/furan
are some of the most toxic compounds known due to their bioaccumulation
potential and wide range of health effects, including carcinogenesis,
at exceedingly low doses. Exposure via indirect pathways is a chief
reason that Congress singled our dioxin/furan for priority MACT control
in CAA section 112(c)(6). See S. Rep. No. 128, 101st Cong. 1st Sess. at
154-155. In addition, we note that the beyond-the-floor emission level
of 0.40 ng TEQ/dscm is consistent with historically controlled levels
under MACT for hazardous waste incinerators and cement kilns, and
Portland cement plants. See Sec. Sec. 63.1203(a)(1), 63.1204(a)(1),
and 63.1343(d)(3). Also, EPA has determined previously in the 1999
Hazardous Waste Combustor MACT final rule that dioxin/furan in the
range of 0.40 ng TEQ/dscm or less are necessary for the MACT standards
to be considered generally protective of human health under RCRA (using
the 1985 cancer slope factor), thereby eliminating the need for
separate RCRA standards under the authority of RCRA section 3005(c)(3)
and 40 CFR 270.10(k). Finally, we note that this decision is not
inconsistent with EPA's decision not to promulgate beyond-the-floor
standards for dioxin/furan for hazardous waste burning lightweight
aggregate kilns, cement kilns, and incinerators at cost-effectiveness
values in the range of $530,000 to $827,000 per additional gram of
dioxin/furan TEQ removed. See 64 FR at 52892, 52876, and 52961. In
those cases, EPA determined that controlling dioxin/furan emissions
from a level of 0.40 ng TEQ/dscm to a beyond-the-floor level of 0.20 ng
TEQ/dscm was not warranted because dioxin/furan levels below 0.40 ng
TEQ/dscm are generally considered to be below the level of health risk
concern.
For these reasons, we believe that proposing a beyond-the-floor
standard of 0.40 ng TEQ/dscm is warranted notwithstanding the nonair
quality health and environmental impacts and energy effects identified
above and costs of approximately $1.3 million per additional gram of
dioxin/furan TEQ removed. We specifically request comment on our
decision to propose this beyond-the-floor standard.
b. Beyond-the-Floor Considerations for Boilers Equipped with Wet or
No Control Systems. For liquid fuel-fired boilers equipped with wet or
no air pollution control systems, we evaluated a beyond-the-floor level
of 0.20 ng TEQ/dscm based on activated carbon. The national incremental
annualized compliance cost for these sources to meet this beyond-the-
floor level rather than comply with the floor controls would be
approximately $550,000 and would provide an incremental reduction in
dioxin/furan emissions beyond the MACT floor controls of 0.12 grams TEQ
per year. We evaluated the nonair quality health and environmental
impacts and energy effects of this beyond-the-floor standard and
estimate that the amount of hazardous waste generated would increase by
100 tons per year, an additional 25 trillion Btu per year of natural
gas would be consumed, an additional 4 million gallons per year of
water would be used, and electricity consumption would increase by 0.50
million kW-hours per year. We are not proposing a beyond-the-floor
standard of 0.20 ng TEQ/dscm for liquid boilers that use a wet or no
air pollution control system because it would not be cost-effective at
$4.6 million per gram of TEQ removed.
We are also considering an alternative beyond-the-floor standard
for existing liquid fuel boilers with wet or no particulate matter
control devices of 0.40 ng TEQ/dscm. Although all but one source for
which we have data are currently achieving this emission level, boilers
for which we do not have dioxin/furan emissions data may have emissions
higher than 0.40 ng TEQ/dscm. In addition, dioxin/furan emissions from
a given boiler may vary over time. Other factors that may contribute
substantially to dioxin/furan formation, such as the level and type of
soot on boiler tubes, or feeding metals that catalyze dioxin/furan
formation reactions, differ across boilers and may change over time at
a given boiler. Thus, dioxin/furan levels for these sources may be
higher than 0.40 ng TEQ/dscm. For example, we recently obtained dioxin/
furan emissions data for a liquid fuel-fired boiler equipped with a wet
emission control system documenting emissions of 1.4 ng TEQ/dscm.\147\
To control dioxin/furan emissions to a beyond-the-floor standard of
0.40 ng TEQ/dscm, you would use activated carbon. We specifically
request comment on this beyond-the-floor option, including how we
should estimate compliance costs and emissions reductions.
---------------------------------------------------------------------------

\147\ These data were recently obtained and are not in the MACT
data base. See ``Region 4 Boiler Dioxin Data,'' Excel spreadsheet,
March 10, 2004.
---------------------------------------------------------------------------

3. What Is the Rationale for the MACT Floor for New Sources?
The calculated floor level for new liquid fuel boilers equipped
with dry air pollution control systems is 0.015 ng TEQ/dscm, which we
identified using the Emissions Approach. If dioxin/furan emissions
could be controlled predominantly by controlling the gas temperature at
the inlet to the dry particulate matter control device, this would be
the emission level that the single best performing source could be
expected to achieve in 99 out of 100 future tests when operating under
conditions identical to the compliance test conditions during which the
emissions data were obtained. This emission level may not be replicable
by this source and duplicable by other (new) sources, however, because
factors other than flue gas temperature control at the control device
may affect dioxin/furan emissions. See discussion of this issue in the
context of the floor level for existing sources. Therefore, we propose
to establish the floor level as 0.015 ng TEQ/dscm or control of flue
gas temperature not to exceed 400 [deg]F at the inlet to the
particulate matter control device.
As previously discussed, we believe that it would be inappropriate
to establish a numerical dioxin/furan emission floor level for liquid
boilers with wet or with no air pollution control systems. Therefore,
we propose floor control for these units as good combustion practices
provided by complying with the proposed destruction and removal
efficiency and carbon monoxide/hydrocarbon standards.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated use of activated carbon as beyond-the-floor control
for further reduction of dioxin/furan emissions. Activated carbon has
been demonstrated for controlling dioxin/furan in various combustion
applications.
a. Beyond-the-Floor Considerations for Boilers Equipped with Dry
Control Systems. For liquid fuel-fired boilers using dry air pollution
control equipment, we evaluated a beyond-the-floor level of 0.01 ng
TEQ/dscm using activated carbon injection. The national incremental
annualized compliance cost

[[Page 21286]]

for a source with an average gas flowrate to meet this beyond-the-floor
level rather than comply with the floor controls would be approximately
$0.15 million and would provide an incremental reduction in dioxin/
furan emissions beyond the MACT floor controls of 0.005 grams TEQ per
year. We evaluated the nonair quality health and environmental impacts
and energy effects of this beyond-the-floor standard and estimate that,
for a new liquid fuel-fired boiler with average gas flowrate, the
amount of hazardous waste generated would increase by 120 tons per year
and electricity consumption would increase by 0.1 million kW-hours per
year. After considering these impacts and costs of approximately $32
million per additional gram of dioxin/furan removed, we are not
proposing a beyond-the-floor standard of 0.01 ng TEQ/dscm for liquid
fuel-fired boilers using dry air pollution control systems.
We are also considering an alternative beyond-the-floor standard of
0.40 ng TEQ/dscm for new liquid fuel boilers equipped with a dry
particulate matter control device. A new source that achieves the floor
level by controlling the gas temperature at the inlet to the dry
particulate matter control device to 400 [deg]F may have dioxin/furan
emissions at levels far exceeding 0.40 ng TEQ/dscm. See discussion
above regarding factors other than gas temperature at the control
device that can affect dioxin/furan emissions from liquid fuel-fired
boilers (and discussion of emissions of 2.4 ng TEQ/dscm for a boiler
operating a fabric filter at 410 [deg]F). Therefore, it may be
appropriate to establish a beyond-the-floor standard to limit emissions
to 0.40 ng TEQ/dscm based on use of activated carbon injection. We also
note that this beyond-the-floor standard may be appropriate to ensure
that emission levels from new sources do not exceed the proposed 0.40
ng TEQ/dscm beyond-the-floor standard for existing sources. Because
standards for new sources are based on the single best performing
source while standards for existing sources are based on the average of
the best 12% (or best 5) performing sources, standards for new sources
should not be less stringent than standards for existing sources. We
specifically request comment on this beyond-the-floor option, including
how we should estimate compliance costs and emissions reductions.
b. Beyond-the-Floor Considerations for Boilers Equipped with Wet or
No Control Systems. We evaluated a beyond-the-floor level of 0.20 ng
TEQ/dscm for liquid fuel-fired boilers equipped with wet or with no air
pollution control systems based on use of activated carbon. The
national incremental annualized compliance cost for a source with
average gas flowrate to meet this beyond-the-floor level rather than
comply with the floor controls would be approximately $0.15 million and
would provide an incremental reduction in dioxin/furan emissions beyond
the MACT floor controls of 0.06 grams TEQ per year. We evaluated the
nonair quality health and environmental impacts and energy effects of
this beyond-the-floor standard and estimate that, for a source with
average gas flowrate, the amount of hazardous waste generated would
increase by 120 tons per year and electricity consumption would
increase by 0.1 million kW-hours per year. After considering these
impacts and costs of approximately $2.4 million per additional gram of
dioxin/furan removed, we are not proposing a beyond-the-floor standard
for liquid fuel-fired boilers using a wet or no air pollution control
system.
We are also considering an alternative beyond-the-floor standard of
0.40 ng TEQ/dscm for new liquid fuel boilers equipped with wet or with
no air pollution control systems. A new source that achieves the floor
level--compliance with the standards for carbon monoxide/hydrocarbon
and destruction and removal efficiency--may have high dioxin/furan
emissions at levels far exceeding 0.40 ng TEQ/dscm. See discussion
above regarding factors other than gas temperature at the control
device that can affect dioxin/furan emissions from liquid fuel-fired
boilers. Therefore, it may be appropriate to establish a beyond-the-
floor standard to limit emissions to 0.40 ng TEQ/dscm based on use of
activated carbon. We specifically request comment on this beyond-the-
floor option, including how we should estimate compliance costs and
emissions reductions.

B. What Is the Rationale for the Proposed Standards for Mercury?

We propose to establish standards for existing liquid fuel-fired
boilers that limit emissions of mercury to 3.7E-6 lbs mercury emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste. The proposed standards for new sources would be 3.8E-7
lbs mercury emissions attributable to the hazardous waste per million
Btu heat input from the hazardous waste.\148\ These standards are
expressed as hazardous waste thermal emission concentrations because
liquid fuel-fired boilers burn hazardous waste for energy recovery. See
discussion in Part Two, Section IV.B of the preamble.
---------------------------------------------------------------------------

\148\ As information, EPA did not propose MACT emission
standards for mercury for liquid fuel-fired boilers that do not burn
hazardous waste. See 68 FR 1660 (Jan. 13, 2003). Note that, in
today's rule, we propose to control mercury only in hazardous waste
fuels, an option obviously not available to boilers that do not burn
hazardous waste.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
MACT floor for existing sources is 3.7E-6 lbs mercury emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste, which is based primarily by controlling the feed
concentration of mercury in the hazardous waste. Approximately 11% of
liquid boilers also use wet scrubbers that can control emissions of mercury.
We have normal emissions data within the range of normal emissions
for 32% of the sources.\149\ The normal mercury stack emissions in our
data base are all less than 7 [mu]g/dscm. These emissions are expressed
as mass of mercury (from all feedstocks) per unit of stack gas.
Hazardous waste thermal emissions, available for 12% of sources, range
from 1.0E-7 to 1.0E-5 lbs mercury emissions attributable to the
hazardous waste per million Btu heat input from the hazardous waste.
Hazardous waste thermal emissions represent the mass of mercury
contributed by the hazardous waste per million Btu contributed by the
hazardous waste.
---------------------------------------------------------------------------

\149\ Several owners and operators have used the emissions data
as ``data in lieu of testing'' emissions from other, identical
boilers at the same facility. For purposes of identifying the number
of boilers represented in this paragraph, the percentage includes
the data-in-lieu sources.
---------------------------------------------------------------------------

To identify the MACT floor, we evaluated all normal emissions data
using the Emissions Approach. The calculated floor is 3.7E-6 lbs
mercury emissions attributable to the hazardous waste per million Btu
heat input from the hazardous waste. This is an emission level that the
average of the best performing sources could be expected to achieve in
99 of 100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. We estimate that this floor level is being achieved by 40% of
sources and would reduce mercury emissions by 0.68 tons per year.
Because the floor level is based on normal emissions data,
compliance would be documented by complying with a hazardous waste
mercury thermal feed concentration on an annual rolling average. See
discussion in Part Two, Section XIV.F below.
We did not use the SRE/Feed Approach to identify the floor level
because the vast majority of mercury feed levels in the hazardous waste
and

[[Page 21287]]

the emissions measurements did not have detectable concentrations of
mercury. Given that a system removal efficiency, or SRE, is the
percentage of mercury emitted compared to the amount fed, we concluded
that it would be inappropriate to base this analysis on SREs that were
derived from measurements below detectable levels.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of mercury: (1) Activated carbon injection; and (2) control of mercury
in the hazardous waste feed. For reasons discussed below, we are not
proposing a beyond-the-floor standard for mercury.
a. Use of Activated Carbon Injection. We evaluated activated carbon
injection as beyond-the-floor control for further reduction of mercury
emissions. Activated carbon has been demonstrated for controlling
mercury in several combustion applications; however, currently no
liquid fuel boilers burning hazardous waste uses activated carbon
injection. We evaluated a beyond-the-floor level of 1.1E-6 lbs mercury
emissions attributable to the hazardous waste per million Btu heat
input from the hazardous waste. The national incremental annualized
compliance cost for liquid fuel-fired boilers to meet this beyond-the-
floor level rather than comply with the floor controls would be
approximately $12 million and would provide an incremental reduction in
mercury emissions beyond the MACT floor controls of 0.097 tons per
year. We evaluated nonair quality health and environmental impacts and
energy effects of using activated carbon injection to meet this beyond-
the-floor emission level and estimate that the amount of hazardous
waste generated would increase by 4,800 tons per year and that sources
would consume an additional 44 trillion Btu per year of natural gas and
use an additional 9.6 million kW-hours per year beyond the requirements
to achieve the floor level. Therefore, based on these factors and costs
of approximately $124 million per additional ton of mercury removed, we
are not proposing a beyond-the-floor standard based on activated carbon
injection.\150\
---------------------------------------------------------------------------

\150\ We note that the beyond-the-floor dioxin/furan standard we
propose for liquid fuel-fired boilers equipped with dry particulate
matter control devices would also provide no-cost beyond-the-floor
mercury control for sources that use activated carbon injection to
control dioxin/furan. If such sources achieve the beyond-the-floor
dioxin/furan standard by other means (control of temperature at the
inlet to the control device; control of feedrate of metals that may
catalyze formation of dioxin/furan), however, collateral reductions
in mercury emissions would not be realized.
---------------------------------------------------------------------------

b. Feed Control of Mercury in the Hazardous Waste. We also
evaluated a beyond-the-floor level of 3.0E-6 lbs mercury emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste, which represents a 20% reduction from the floor level.
The national incremental annualized compliance cost for liquid fuel-
fired boilers to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $4.2 million and would
provide an incremental reduction in mercury emissions beyond the MACT
floor controls of 0.036 tons per year. Nonair quality health and
environmental impacts and energy effects are not significant factors
for feedrate control. Therefore, based on these factors and costs of
approximately $115 million per additional ton of mercury removed, we
are not proposing a beyond-the-floor standard based on feed control of
mercury in the hazardous waste.
For the reasons discussed above, we do not propose a beyond-the-
floor standard for mercury for existing sources. We propose a standard
based on the floor level: 3.7E-6 lbs mercury emissions attributable to
the hazardous waste per million Btu heat input from the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
The MACT floor for new sources for mercury would be 3.8E-7 lbs
mercury emissions attributable to the hazardous waste per million Btu
heat input from the hazardous waste and would be implemented as an
annual average because it is based on normal emissions data. This is an
emission level that the single best performing source identified with
the Emissions Approach could be expected to achieve in 99 of 100 future
tests when operating under operating conditions identical to the
compliance test conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated activated carbon injection as beyond-the-floor control
to achieve an emission level of 2.0E-7 lbs mercury emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste. The incremental annualized compliance cost for a new
liquid fuel-fired boiler with average gas flowrate to meet this beyond-
the-floor level, rather than comply with the floor level, would be
approximately $0.15 million and would provide an incremental reduction
in mercury emissions of less than 0.0002 tons per year, for a cost-
effectiveness of $1 billion per ton of mercury removed. We evaluated
the nonair quality health and environmental impacts and energy effects
of this beyond-the-floor standard and estimate that, for a new liquid
fuel-fired boiler with average gas flowrate, the amount of hazardous
waste generated would increase by 120 tons per year and electricity
consumption would increase by 0.1 million kW-hours per year. Although
nonair quality health and environmental impacts and energy effects are
not significant factors, we are not proposing a beyond-the-floor
standard based on activated carbon injection for new sources because it
would not be cost-effective. Therefore, we propose a mercury standard
based on the floor level: 3.8E-7 lbs mercury emissions attributable to
the hazardous waste per million Btu heat input from the hazardous waste.

C. What Is the Rationale for the Proposed Standards for Particulate Matter?

The proposed standards for particulate matter for liquid fuel-fired
boilers are 59 mg/dscm (0.026 gr/dscf) for existing sources and 17 mg/
dscm (0.0076 gr/dscf) for new sources.\151\ The particulate matter
standard serves as a surrogate for nonenumerated HAP metal emissions
attributable to the hazardous waste fuel burned in the boiler. Although
the particulate matter standard would also control nonmercury HAP metal
from nonhazardous waste fuels, the natural gas or fuel oil these
boilers burn as primary or auxiliary fuel do not contain significant
levels of metal HAP.
---------------------------------------------------------------------------

\151\ As information, EPA proposed MACT standards for
particulate matter for solid fuel-fired industrial, commercial, and
institutional boilers that do not burn hazardous waste of 0.035 gr/
dscf for existing sources and 0.013 gr/dscf for new sources.
---------------------------------------------------------------------------

1. What Is the Rationale for the MACT Floor for Existing Sources?
Few liquid fuel-fired boilers are equipped particulate matter
control equipment such as electrostatic precipitators and baghouses,
and, therefore, many sources control particulate matter emissions by
limiting the ash content of the hazardous waste. We have compliance
test emissions data from nearly all liquid boilers representing maximum
allowable emissions. Particulate emissions range from 0.0008 to 0.078
gr/dscf.
To identify the floor level, we evaluated the compliance test emissions

[[Page 21288]]

data associated with the most recent test campaign using the APCD
Approach. The calculated floor is 72 mg/dscm (0.032 gr/dscf), which
considers emissions variability. This is an emission level that the
average of the performing sources could be expected to achieve in 99 of
100 future tests when operating under operating conditions identical to
the compliance test conditions during which the emissions data were
obtained. We estimate that this floor level is being achieved by 44% of
sources and would reduce particulate matter emissions by 1,200 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated use of fabric filters to improve particulate matter
control to achieve a beyond-the-floor standard of 36 mg/dscm (0.016 gr/
dscf). The national incremental annualized compliance cost for liquid
fuel-fired boilers to meet this beyond-the-floor level rather than
comply with the floor controls would be approximately $16 million and
would provide an incremental reduction in particulate matter emissions
beyond the MACT floor controls of 520 tons per year. We evaluated the
nonair quality health and environmental impacts and energy effects of
this beyond-the-floor standard and estimate that the amount of
hazardous waste generated would increase by 520 tons per year and
electricity consumption would increase by 13 million kW-hours per year.
After considering these factors and costs of approximately $30,000 per
additional ton of particulate matter removed, we are not proposing a
beyond-the-floor standard.
For the reasons discussed above, we propose a standard for
particulate matter for existing liquid fuel-fired boilers based on the
floor level: 72 mg/dscm (0.032 gr/dscf).
3. What Is the Rational for the MACT Floor for New Sources?
MACT floor for new sources would be 17 mg/dscm (0.0076 gr/dscf),
considering emissions variability. This is an emission level that the
single best performing source identified by the APCD Approach (i.e.,
the source using a fabric filter \152\ with the lowest emissions) could
be expected to achieve in 99 of 100 future tests when operating under
operating conditions identical to the compliance test conditions during
which the emissions data were obtained.
---------------------------------------------------------------------------

\152\ The source also is equipped with a high efficiency
particulate air (HEPA) filter.
---------------------------------------------------------------------------

4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated use of an advanced fabric filter using high efficiency
membrane bag material and a low air to cloth ratio to achieve a beyond-
the-floor emission level of 9 mg/dscm (0.0040 gr/dscf). The incremental
annualized cost for a new liquid fuel-fired boiler with average gas
flowrate to meet this beyond-the-floor level, rather than comply with
the floor level, would be approximately $0.15 million and would provide
an incremental reduction in particulate emissions of approximately 2.9
tons per year, for a cost-effectiveness of $53,000 per ton of
particulate matter removed. We evaluated the nonair quality health and
environmental impacts and energy effects of this beyond-the-floor
standard and estimate that, for a new liquid fuel-fired boiler with
average gas flowrate, the amount of hazardous waste generated would
increase by 3 tons per year and electricity consumption would increase
by 0.54 million kW-hours per year. Considering these factors and cost-
effectiveness, we conclude that a beyond-the-floor standard of 9 mg/
dscm is not warranted.
For the reasons discussed above, we propose a floor-based standard
for particulate matter for new liquid fuel-fired boilers: 9.8 mg/dscm
(0.0043 gr/dscf)

D. What Is the Rationale for the Proposed Standards for Semivolatile Metals?

We propose a standard for existing liquid fuel-fired boilers that
limits emissions of semivolatile metals (cadmium and lead, combined) to
1.1E-5 lbs semivolatile metals emissions attributable to the hazardous
waste per million Btu heat input from the hazardous waste. The proposed
standard for new sources is 4.3E-6 lbs semivolatile metals emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
MACT floor for existing sources is 1.1E-5 lbs semivolatile metals
emissions attributable to the hazardous waste per million Btu heat
input of the hazardous waste, which is based on particulate matter
control (for those few sources using a control device) and controlling
the feedrate of semivolatile metals in the hazardous waste.
We have emissions data within the range of normal emissions for
nearly 40% of the sources.\153\ The normal semivolatile stack emissions
in our database range from less than 1 to 46 ug/dscm. These emissions
are expressed conventionally as mass of semivolatile metals (from all
feedstocks) per unit of stack gas. Hazardous waste thermal emissions,
available for 25% of sources, range from 1.2E-6 to 4.8E-5 lbs
semivolatile metals emissions attributable to the hazardous waste per
million Btu heat input of the hazardous waste.
---------------------------------------------------------------------------

\153\ Several owners and operators have used the emissions data
as ``data in lieu of testing'' emissions from other, identical
boilers at the same facility. For purposes of identifying the number
of boilers represented in this paragraph, the percentages include
the data-in-lieu sources.
---------------------------------------------------------------------------

We identified a MACT floor of 1.1E-5 expressed as a hazardous waste
thermal emission by applying the Emissions Approach to the normal
hazardous waste thermal emissions data.\154\ This is an emission level
that the average of the best performing sources could be expected to
achieve in 99 of 100 future tests when operating under conditions
identical to the compliance test conditions during which the emissions
data were obtained. We estimate that this floor level is being achieved
by 33% of sources and would reduce semivolatile metals emissions by 1.7
tons per year.
---------------------------------------------------------------------------

\154\ We propose to use the Emissions Approach rather than the
SRE/Feed approach because our data base is comprised of emissions
obtained during normal rather than compliance test operations.
Because of the relatively low semivolatile metal feedrates during
normal operations, we are concerned that the system removal
efficiencies that we would calculate may be inaccurate (e.g.,
sampling and analysis imprecision at low feed rates can have a
substantial impact on calculated system removal efficiencies).
---------------------------------------------------------------------------

[[Page 21289]]

for further reduction of semivolatile metals emissions. We evaluated a
beyond-the-floor level of 5.5E-6 lbs semivolatile metals emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste. The national incremental annualized compliance cost
for liquid fuel-fired boilers to meet this beyond-the-floor level
rather than comply with the floor controls would be approximately $6.5
million and would provide an incremental reduction in semivolatile
metals emissions beyond the MACT floor controls of 0.06 tons per year.
We evaluated nonair quality health and environmental impacts and energy
effects and determined that this beyond-the-floor option would increase
the amount of hazardous waste generated by approximately 45 tons per
year and would increase electricity usage by 0.8 million kW-hours per
year. After considering these factors and costs of approximately $100
million per additional ton of semivolatile metals removed, we are not
proposing a beyond-the-floor standard based on improved particulate
matter control.
b. Feed Control of Semivolatile Metals in the Hazardous Waste. We
also evaluated a beyond-the-floor level of 8.8E-6 lbs semivolatile
metals emissions attributable to the hazardous waste per million Btu
heat input from the hazardous waste, which represents a 20% reduction
from the floor level. The national incremental annualized compliance
cost for liquid fuel-fired boilers to meet this beyond-the-floor level
rather than comply with the floor controls would be approximately $4.8
million and would provide an incremental reduction in semivolatile
metals emissions beyond the MACT floor controls of 0.06 tons per year.
Nonair quality health and environmental impacts and energy effects are
not significant factors for feedrate control. Therefore, considering
these factors and costs of approximately $81 million per additional ton
of semivolatile metals removed, we are not proposing a beyond-the-floor
standard based on feed control of semivolatile metals in the hazardous
waste.
For the reasons discussed above, we propose a floor standard for
semivolatile metals for existing liquid fuel-fired boilers of 1.1E-5
lbs semivolatile metals emissions attributable to the hazardous waste
per million Btu heat input from the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
The MACT floor for new sources for semivolatile metals would be
4.3E-6 lbs semivolatile metals emissions attributable to the hazardous
waste per million Btu heat input from the hazardous waste. This is an
emission level that the single best performing source identified with
the Emissions Approach \155\ could be expected to achieve in 99 of 100
future tests when operating under operating conditions identical to the
compliance test conditions during which the emissions data were obtained.
---------------------------------------------------------------------------

\155\ We use the Emissions Approach rather than the SRE/Feed
Approach when we use normal rather than compliance test data to
establish the standard, as discussed previously.
---------------------------------------------------------------------------

Because the floor level is based on normal emissions data,
compliance would be documented by complying with a hazardous waste
mercury thermal feed concentration on an annual rolling average. See
discussion in Part Two, Section XIV.F below.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated a beyond-the-floor level of 2.1E-6 lbs semivolatile
metals emissions attributable to the hazardous waste per million Btu
heat input from the hazardous waste based on an advanced fabric filter
using high efficiency membrane bag material and a low air to cloth
ratio. The incremental annualized compliance cost for a new liquid
fuel-fired boiler with average gas flowrate to meet this beyond-the-
floor level, rather than comply with the floor level, would be
approximately $0.15 million and would provide an incremental reduction
in semivolatile metals emissions of less than 0.002 tons per year, for
a cost-effectiveness of $87 million per ton of semivolatile metals
removed. We evaluated the nonair quality health and environmental
impacts and energy effects of this beyond-the-floor standard and
estimate that, for a new liquid fuel-fired boiler with average gas
flowrate, the amount of hazardous waste generated would increase by 2
tons per year and electricity consumption would increase by 0.54
million kW-hours per year. Considering these factors and cost-
effectiveness, we conclude that a beyond-the-floor standard is not
warranted. Therefore, we propose a semivolatile metals standard based
on the floor level: 4.3E-6 lbs semivolatile metals emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste for new sources.

E. What Is the Rationale for the Proposed Standards for Chromium?

We propose to establish standards for existing and new liquid fuel-
fired boilers that limit emissions of chromium to 1.1E-4 lbs and 3.6E-5
lbs chromium emissions attributable to the hazardous waste per million
Btu heat input from the hazardous waste, respectively.
We propose to establish emission standards on chromium-only because
our data base has very limited compliance test data on emissions of
total low volatile metals: arsenic, beryllium, and chromium. We have
compliance test data on only two sources for total low volatile metals
emissions while we have compliance test data for 12 sources for
chromium-only. Although we have total low volatile metals emissions for
12 sources when operating under normal operations, we prefer to use
compliance test data to establish the floor because they better address
emissions variability.
By establishing a low volatile metal floor based on chromium
emissions only we are relying on the particulate matter standard to
control the other enumerated low volatile metals--arsenic and
beryllium--as well as nonenumerated metal HAP. We request comment on
this approach and note that, as discussed below, an alternative
approach would be to establish a MACT floor based on normal emissions
data for all three enumerated low volatile metals.
We request comment on whether the compliance test data for
chromium-only are appropriate for establishing a MACT floor for
chromium. We are concerned that some sources in our data base may have
used chromium as a surrogate for arsenic and beryllium during RCRA
compliance testing such that their chromium emissions may be more
representative of their total low volatile metals emissions than only
chromium. If we determine this to be the case, we could apply the floor
we calculate using chromium emissions to total low volatile metal
emissions. Alternatively, we could use the normal emissions data we
have on 12 sources and our MACT methodology to establish a total low
volatile metals floor.
1. What Is the Rationale for the MACT Floor for Existing Sources?
MACT floor for existing sources is 1.1E-4 lbs chromium emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste, which is based on particulate matter control (for
those few sources using a control device) and controlling the feed
concentration of chromium in the hazardous waste.
We have compliance test emissions data for approximately 17% of the

[[Page 21290]]

sources.\156\ The compliance test chromium stack emissions in our
database range from 2 to 900 ug/dscm. These emissions are expressed as
mass of chromium (from all feedstocks) per unit of stack gas. Hazardous
waste thermal emissions, available for 13% of sources, range from 3.2E-
6 to 8.8E-4 lbs chromium emissions attributable to the hazardous waste
per million Btu heat input from the hazardous waste.
---------------------------------------------------------------------------

\156\ Several owners and operators have used the emissions data
as ``data in lieu of testing'' emissions from other, identical
boilers at the same facility. For purposes of identifying the number
of boilers represented in this paragraph, the percentages include
the data-in-lieu sources.
---------------------------------------------------------------------------

To identify the floor level, we evaluated all compliance test
thermal emissions data using the SRE/Feed Approach (see discussion in
Section VI.C above). The calculated floor is 1.1E-4 lbs chromium
emissions attributable to the hazardous waste per million Btu heat
input from the hazardous waste feed, which considers emissions
variability. This is an emission level that the average of the best
performing sources could be expected to achieve in 99 of 100 future
tests when operating under conditions identical to the compliance test
conditions during which the emissions data were obtained. We estimate
that this floor level is being achieved by 36% of sources and would
reduce chromium emissions by 9.4 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of chromium emissions: (1) Use of a fabric filter to improve
particulate matter control; and (2) control of chromium in the
hazardous waste feed. For reasons discussed below, we are not proposing
a beyond-the-floor standard for chromium.
a. Use of a Fabric Filter to Improve Particulate Matter Control. We
evaluated use of a fabric filter as beyond-the-floor control for
further reduction of chromium emissions. We evaluated a beyond-the-
floor level of 5.5E-5 lbs chromium emissions attributable to the
hazardous waste per million Btu heat input from the hazardous waste.
The national incremental annualized compliance cost for liquid fuel-
fired boilers to meet this beyond-the-floor level rather than comply
with the floor controls would be approximately $5.9 million and would
provide an incremental reduction in chromium emissions beyond the MACT
floor controls of 0.50 tons per year. We evaluated nonair quality
health and environmental impacts and energy effects and determined that
this beyond-the-floor option would increase the amount of hazardous
waste generated by approximately 160 tons per year and would increase
electricity usage by 3.0 million kW-hours per year. Based on these
impacts and a cost of approximately $12 million per additional ton of
chromium removed, we are not proposing a beyond-the-floor standard
based on improved particulate matter control.
b. Feed Control of Chromium in the Hazardous Waste. We evaluated
additional feed control of chromium in the hazardous waste as a beyond-
the-floor control technique to reduce floor emission levels by 25% to
achieve a standard of 8.8E-5 lbs chromium emissions attributable to the
hazardous waste per million Btu heat input from the hazardous waste.
This beyond-the-floor level of control would reduce chromium by an
additional 0.20 tons per year at a cost-effectiveness of $22 million
per ton of chromium removed. Nonair quality health and environmental
impacts and energy effects are not significant factors for feedrate
control. We conclude that use of additional hazardous waste chromium
feedrate control would not be cost-effective and are not proposing a
beyond-the-floor standard based on this control technique.
For the reasons discussed above, we do not propose a beyond-the-
floor standard for chromium. Consequently, we propose to establish the
emission standard for existing liquid fuel-fired boilers at the floor
level: a hazardous waste thermal emission standard of 1.1E-4 lbs
chromium emissions attributable to hazardous waste per million Btu of
hazardous waste feed.
3. What Is the Rationale for the MACT Floor for New Sources?
The MACT floor for new sources for chromium would be 3.6E-5 lbs
chromium emissions attributable to the hazardous waste per million Btu
heat input from the hazardous waste feed. This is an emission level
that the single best performing source identified with the SRE/Feed
Approach could be expected to achieve in 99 of 100 future tests when
operating under operating conditions identical to the compliance test
conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated use of an advanced fabric filter using high efficiency
membrane bag material and a low air to cloth ratio as beyond-the-floor
control to reduce chromium emissions to a beyond-the-floor level of
1.8E-5 lbs chromium emissions attributable to the hazardous waste per
million Btu heat input from the hazardous waste. The incremental
annualized compliance cost for a new liquid fuel-fired boiler with
average gas flowrate to meet this beyond-the-floor level, rather than
comply with the floor level, would be approximately $0.15 million and
would provide an incremental reduction in chromium emissions of 0.014
tons per year, for a cost-effectiveness of $11 million per ton of
chromium removed. We evaluated the nonair quality health and
environmental impacts and energy effects of this beyond-the-floor
standard and estimate that, for a new liquid fuel-fired boiler with
average gas flowrate, the amount of hazardous waste generated would
increase by 2 tons per year and electricity consumption would increase
by 0.54 million kW-hours per year. Considering these factors and cost-
effectiveness, we conclude that a beyond-the-floor standard is not
warranted. Therefore, we propose a chromium emission standard for new
sources based on the floor level: 3.6E-5 lbs chromium emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste feed.

F. What Is the Rationale for the Proposed Standards for Total Chlorine?

We are proposing to establish a standard for existing liquid fuel-
fired boilers that limit emissions of hydrogen chloride and chlorine
gas (i.e., total chlorine) to 2.5E-2 lbs total chlorine emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste. The proposed standard for new sources would be 7.2E-4
lbs total chlorine emissions attributable to the hazardous waste per
million Btu heat input from the hazardous waste.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Most liquid fuel-fired boilers that burn hazardous waste do not
have back-end controls such as wet scrubbers for total chlorine
control. For these sources, total chlorine emissions are controlled by
most sources by controlling the feedrate of chlorine in the hazardous
waste feed. Approximately 15% of sources use wet scrubbing systems to
control total chlorine emissions.
We have compliance test data representing maximum emissions for 40%
of the boilers. Total chlorine emissions range from less than 1 to 900
ppmv. Hazardous waste thermal emissions, available for 27% of boilers,
range from 1.00E-4 to 1.4 lbs total

[[Page 21291]]

chlorine emissions attributable to the hazardous waste per million Btu
heat input from the hazardous waste.
The calculated floor is 2.5E-2 lbs total chlorine emissions
attributable to the hazardous waste per million Btu heat input from the
hazardous waste using the SRE/Feed Approach to identify the best
performing sources (see discussion in section VI.C above). This is an
emission level that the average of the performing sources could be
expected to achieve in 99 of 100 future tests when operating under
operating conditions identical to the compliance test conditions during
which the emissions data were obtained. We estimate that this floor
level is being achieved by 70% of sources and would reduce total
chlorine emissions by 660 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We identified two potential beyond-the-floor techniques for control
of total chlorine emissions: (1) Use of a wet scrubber; and (2) control
of chlorine in the hazardous waste feed. For reasons discussed below,
we are not proposing a beyond-the-floor standard for total chlorine.
a. Use of Wet Scrubbing. We considered a beyond-the-floor standard
of 1.3E-2 lbs total chlorine emissions attributable to the hazardous
waste per million Btu heat input from the hazardous waste based on wet
scrubbing to reduce emissions beyond the floor level by 50 percent. The
national incremental annualized compliance cost for liquid fuel-fired
boilers to meet this beyond-the-floor level rather than comply with the
floor controls would be approximately $7.8 million and would provide an
incremental reduction in total chlorine emissions beyond the MACT floor
controls of 430 tons per year. We evaluated nonair quality health and
environmental impacts and energy effects and determined that this
beyond-the-floor option would increase both the amount of hazardous
wastewater generated and water usage by approximately 3.2 billion
gallons per year and would increase electricity usage by 30 million kW-
hours per year. Considering these impacts and a cost-effectiveness of
approximately $18,000 per additional ton of total chlorine removed, we
are not proposing a beyond-the-floor standard based on wet scrubbing.
b. Feed Control of Chlorine in the Hazardous Waste. We evaluated
additional feed control of chlorine in the hazardous waste as a beyond-
the-floor control technique to reduce floor emission levels by 20% to
achieve a standard of 2.0E-2 lbs total chlorine emissions attributable
to the hazardous waste per million Btu heat input from the hazardous
waste. The national incremental annualized compliance cost for liquid
fuel-fired boilers to meet this beyond-the-floor level rather than
comply with the floor controls would be approximately $3.9 million and
would provide an incremental reduction in total chlorine emissions
beyond the MACT floor controls of 170 tons per year. Nonair quality
health and environmental impacts and energy effects are not significant
factors for feedrate control. We conclude that use of additional
hazardous waste chlorine feedrate control would not be cost-effective
at $23,000 per ton of total chlorine removed and are not proposing a
beyond-the-floor standard based on this control technique.
For the reasons discussed above, we propose a total chlorine
standard for existing liquid fuel-fired boilers based on the floor
level: 2.5E-2 lbs total chlorine emissions attributable to the
hazardous waste per million Btu heat input from the hazardous waste.
3. What Is the Rationale for the MACT Floor for New Sources?
The MACT floor for new sources for total chlorine would be 7.2E-4
lbs total chlorine emissions attributable to the hazardous waste per
million Btu heat input from the hazardous waste. This is an emission
level that the single best performing source identified with the SRE/
Feed Approach could be expected to achieve in 99 of 100 future tests
when operating under operating conditions identical to the compliance
test conditions during which the emissions data were obtained.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated wet scrubbing as beyond-the-floor control for further
reductions in total chlorine emissions to achieve a beyond-the-floor
level of 3.6E-4 lbs total chlorine emissions attributable to the
hazardous waste per million Btu heat input from the hazardous waste.
The incremental annualized compliance cost for a new liquid fuel-fired
boiler with an average gas flowrate to meet this beyond-the-floor
level, rather than comply with the floor level, would be approximately
$0.44 million and would provide an incremental reduction in total
chlorine emissions of approximately 0.13 tons per year, for a cost-
effectiveness of $3.3 million per ton of total chlorine removed. We
evaluated nonair quality health and environmental impacts and energy
effects and determined that, for a new source with average an average
gas flowrate, this beyond-the-floor option would increase both the
amount of hazardous wastewater generated and water usage by
approximately 140 million gallons per year and would increase
electricity usage by 1.3 million kW-hours per year. After considering
these impacts and cost-effectiveness, we conclude that a beyond-the-
floor standard based on wet scrubbing for new liquid fuel-fired boilers
is not warranted.
For the reasons discussed above, we propose a total chlorine
standard for new sources based on the floor level: 7.2E-4 lbs total
chlorine emissions attributable to the hazardous waste per million Btu
heat input from the hazardous waste.

G. What Is the Rationale for the Proposed Standards for Carbon Monoxide
or Hydrocarbons?

To control emissions of organic HAP, existing and new sources would
be required to comply with either a carbon monoxide standard of 100
ppmv or a hydrocarbon standard of 10 ppmv.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Liquid fuel-fired boilers that burn hazardous waste are currently
subject to RCRA standards that require compliance with either a carbon
monoxide standard of 100 ppmv, or a hydrocarbon standard of 20 ppmv.
Compliance is based on an hourly rolling average as measured with a
CEMS. See Sec. 266.104(a). We are proposing today floor standards of
100 ppmv for carbon monoxide or 10 ppmv for hydrocarbons.
Floor control for existing sources is operating under good
combustion practices including: (1) Providing adequate excess air with
use of oxygen CEMS and feedback air input control; (2) providing
adequate fuel/air mixing; (3) homogenizing hazardous waste fuels (such
as by blending or size reduction) to control combustion upsets due to
very high or very low volatile content wastes; (4) regulating waste and
air feedrates to ensure proper combustion temperature and residence
time; (5) characterizing waste prior to burning for combustion-related
composition (including parameters such as heating value, volatile
content, liquid waste viscosity, etc.); (6) ensuring the source is
operated by qualified, experienced operators; and (7) periodic
inspection and maintenance of combustion system components such as
burners, fuel and air supply lines, injection nozzles, etc. Given that
there are many interdependent parameters that affect combustion
efficiency and thus carbon

[[Page 21292]]

monoxide and hydrocarbon emissions, we are not able to quantify ``good
combustion practices.''
All liquid fuel-fired boilers are currently complying with the RCRA
carbon monoxide limit of 100 ppmv on an hourly rolling average. No
boilers are complying with the RCRA hydrocarbon limit of 20 ppmv on an
hourly rolling average.
We propose a floor level for carbon monoxide level of 100 ppmv
because it is a currently enforceable Federal standard. Although the
best performing sources are achieving carbon monoxide levels below 100
ppmv, it is not appropriate to establish a lower floor level because
carbon monoxide is a surrogate for nondioxin/furan organic HAP. As
such, lowering the carbon monoxide floor may not significantly reduce
organic HAP emissions. In addition, it would be inappropriate to apply
a MACT methodology to the carbon monoxide emissions from the best
performing sources because those sources may not be able to replicate
their emission levels. This is because there are myriad factors that
affect combustion efficiency and, subsequently, carbon monoxide
emissions. Extremely low carbon monoxide emissions cannot be assured by
controlling only one or two operating parameters We note also that we
used this rationale to establish a carbon monoxide standard of 100 ppmv
for Phase I sources in the September 1999 Final Rule.
We propose a floor level for hydrocarbons of 10 ppmv even though
the currently enforceable standard is 20 ppmv because: (1) The two
sources that comply with the RCRA hydrocarbon standard can readily
achieve 10 ppmv; and (2) reducing hydrocarbon emissions within the
range of 20 ppmv to 10 ppmv should reduce emissions of nondioxin/furan
organic HAP. We do not apply a prescriptive MACT methodology to
establish a hydrocarbon floor below 10 ppmv, however, because we have
data from only two sources. In addition, we note that the hydrocarbon
emission standard for Phase I sources established in the September 1999
Final Rule is 10 ppmv also.
There would be no incremental emission reductions associated with
these floors because all sources are currently achieving the floor levels.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We considered beyond-the-floor levels for carbon monoxide and
hydrocarbons based on use of better combustion practices but conclude
that they may not be replicable by the best performing sources nor
duplicable by other sources given that we cannot quantify good
combustion practices. Moreover, as discussed above, we cannot ensure
that lower carbon monoxide or hydrocarbon levels would significantly
reduce emissions of nondioxin/furan organic HAP.
Nonair quality health and environmental impacts and energy
requirements are not significant factors for use of better combustion
practices as beyond-the-floor control.
For these reasons, we conclude that beyond-the-floor standards for
carbon monoxide and hydrocarbons are not warranted for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for new sources would be the same as the floor for
existing sources--100 ppmv for carbon monoxide and 10 ppmv for
hydrocarbons--and based on the same rationale.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
As discussed in the context of beyond-the-floor considerations for
existing sources, we considered beyond-the-floor standards for carbon
monoxide and hydrocarbons for new sources based on use of better
combustion practices. But we conclude that beyond the floor standards
may not be replicable by the best performing sources nor duplicable by
other sources given that we cannot quantify good combustion practices.
Moreover, we cannot ensure that lower carbon monoxide or hydrocarbon
levels would significantly reduce emissions of nondioxin/furan organic HAP.
Nonair quality health and environmental impacts and energy
requirements are not significant factors for use of better combustion
practices as beyond-the-floor control.
For these reasons, we are not proposing a beyond-the-floor standard
for carbon monoxide and hydrocarbons.

H. What Is the Rationale for the Proposed Standard for Destruction and
Removal Efficiency?

To control emissions of organic HAP, existing and new sources would
be required to comply with a destruction and removal efficiency (DRE)
of 99.99% for organic HAP. For sources burning hazardous wastes F020,
F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999%
for organic HAP.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Liquid fuel-fired boilers that burn hazardous waste are currently
subject to RCRA DRE standards that require 99.99% destruction of
designated principal organic hazardous constituents (POHCs). For
sources that burn hazardous wastes F020, F021, F022, F023, F026, or
F027, however, the DRE standard is 99.9999% destruction of designated
POHCs. See Sec. 266.104(a).
The DRE standard helps ensure that a combustor is operating under
good combustion practices and thus minimizing emissions of organic HAP.
Under the MACT compliance regime, sources would designate POHCs that
are organic HAP or that are surrogates for organic HAP.
We propose to establish the RCRA DRE standard as the floor for
existing sources because it is a currently enforceable Federal
standard. There would be no incremental costs or emission reductions
associated with this floor because sources are currently complying with
the standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We considered a beyond-the-floor level for DRE based on use of
better combustion practices but conclude that it may not be replicable
by the best performing sources nor duplicable by other sources given
that we cannot quantify better combustion practices. Moreover, we
cannot ensure that a higher DRE standard would significantly reduce
emissions of organic HAP given that DRE measures the destruction of
organic HAP present in the boiler feed rather than gross emissions of
organic HAP. Although a source's combustion practices may be adequate
to destroy particular organic HAP in the feed, other organic HAP that
may be emitted as products of incomplete combustion may not be
controlled by the DRE standard.\157\
---------------------------------------------------------------------------

\157\ The carbon monoxide/hydrocarbon emission standard would
control organic HAP that are products of incomplete combustion by
also ensuring use of good combustion practices.
---------------------------------------------------------------------------

For these reasons, and after considering nonair quality health and
environmental impacts and energy requirements, we are not proposing a
beyond-the-floor DRE standard for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
We propose to establish the RCRA DRE standard as the floor for new
sources because it is a currently enforceable Federal standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
Using the same rationale as we used to consider a beyond-the-floor DRE

[[Page 21293]]

standard for existing sources, we conclude that a beyond-the-floor DRE
standard for new sources is not warranted. Consequently, after
considering nonair quality health and environmental impacts and energy
requirements, we are proposing the floor DRE standard for new sources.

XII. How Did EPA Determine the Proposed Emission Standards for
Hazardous Waste Burning Hydrochloric Acid Production Furnaces?

The proposed standards for existing and new hydrochloric acid
production furnaces that burn hazardous waste are summarized in the
table below. See proposed Sec. 63.1218.

Proposed Standards for Existing and New Hydrochloric Acid Production
Furnaces
------------------------------------------------------------------------
Emission standard\1\
Hazardous air pollutant or -------------------------------------------
surrogate Existing sources New sources
------------------------------------------------------------------------
Dioxin and furan............ 0.40 ng TEQ/dscm.... 0.40 ng TEQ/dscm.
Hydrochloric acid and 14 ppmv or 99.9927% 1.2 ppmv or
chlorine gas \2\. System Removal 99.99937% System
Efficiency. Removal Efficiency.
Carbon monoxide or 100 ppmv carbon 100 ppmv carbon
hydrocarbons \3\. monoxide or 10 ppmv monoxide or 10 ppmv
hydrocarbons. hydrocarbons.
Destruction and Removal For existing and new sources, 99.99% for
Efficiency. each principal organic hazardous
constituent (POHC). For sources burning
hazardous wastes F020, F021, F022, F023,
F026, or F027, however, 99.9999% for each
POHC.
------------------------------------------------------------------------
\1\ All emission standards are corrected to 7% oxygen, dry basis.
\2\ Combined standard, reported as a chloride (Cl(-)) equivalent.
\3\ Hourly rolling average. Hydrocarbons reported as propane.

A. What Is the Rationale for the Proposed Standards for Dioxin and Furan?

The proposed standard for dioxin/furan for existing and new sources
is 0.40 ng TEQ/dscm.
1. What Is the Rationale for the MACT Floor for Existing Sources?
The proposed MACT floor for existing sources is compliance with the
proposed CO/HC emission standard and compliance with the proposed DRE
standard.
Hydrochloric acid production furnaces use wet scrubbers to remove
hydrochloric acid from combustion gases to produce the hydrochloric
acid product and to minimize residual emissions of hydrochloric acid
and chlorine gas. Thus, dioxin/furan cannot be formed on particulate
surfaces in the emission control device as can happen with
electrostatic precipitators and fabric filters. Nonetheless, dioxin/
furan emissions from hydrochloric acid production furnaces can be very
high. We have dioxin/furan emissions data for 18 test conditions
representing 14 of the 17 sources. Dioxin/furan emissions range from
0.02 ng TEQ/dscm to 6.8 ng TEQ/dscm.
We investigated whether it would be appropriate to establish
separate dioxin/furan standards for furnaces equipped with waste heat
recovery boilers versus those without boilers. Ten of the 17
hydrochloric acid production furnaces are equipped with boilers. We
considered whether waste heat recovery boilers may be causing the
elevated dioxin/furan emissions, as appeared to be the case for
incinerators equipped with boilers. See 62 FR at 24220 (May 2, 1997)
where we explain that heat recovery boilers preclude rapid temperature
quench of combustion gases, thus allowing particle-catalyzed formation
of dioxin/furan. The dioxin/furan data for hydrochloric acid production
furnaces indicate, however, that furnaces with boilers have dioxin/
furan emissions ranging from 0.05 to 6.8 ng TEQ/dscm, while furnaces
without boilers have dioxin/furan emissions ranging from 0.02 to 1.7 ng
TEQ/dscm. Based on a statistical analysis of the data sets (see
discussion in Part Two, Section II.E), we conclude that the dioxin/
furan emissions for furnaces equipped with boilers are not
significantly different from dioxin/furan emissions for furnaces
without boilers. Thus, we conclude that separate dioxin/furan emission
standards are not warranted.
We cannot identify or quantify a dioxin/furan control mechanism for
these furnaces. Consequently, we conclude that establishing a floor
emission level based on emissions from the best performing sources
would not be appropriate because the best performing sources may not be
able to replicate their emission levels, and other sources may not be
able to duplicate those emission levels.
We note, however, that dioxin/furan emissions can be affected by
the furnace's combustion efficiency. Operating under poor combustion
conditions can generate dioxin/furan and organic precursors that may
contribute to post-combustion dioxin/furan formation. Because we cannot
quantify a dioxin/furan floor level and because hydrochloric acid
production furnaces are currently required to operate under good
combustion practices by RCRA standards for carbon monoxide/hydrocarbons
and destruction and removal efficiency, we identify those RCRA
standards as the proposed MACT floor. See Sec. 266.104 requiring
compliance with destruction and removal efficiency and carbon monoxide/
hydrocarbon emission standards.\158\ We also find, as required by CAA
section 112(h)(1), that these proposed standards are consistent with
section 112(d)'s objective of reducing emissions of these HAP to the
extent achievable.
---------------------------------------------------------------------------

\158\ Section 266.104 requires compliance with a carbon monoxide
limit of 100 ppmv or a hydrocarbon limit of 20 ppmv, while we are
proposing today a carbon monoxide limit of 100 ppmv or a hydrocarbon
limit of 10 ppmv (see Section XII.H in the text). Although today's
proposed hydrocarbon limit is more stringent than the current limit
for hydrochloric acid production furnaces, all sources chose to
comply with the 100 ppmv carbon monoxide limit.
---------------------------------------------------------------------------

We also request comment on an alternative MACT floor expressed as a
dioxin/furan emission concentration. Although it would be inappropriate
to identify a floor concentration based on the average emissions of the
best performing sources as discussed above, we could identify the floor
as the highest emission concentration from any source in our data base,
after considering emissions variability. Under this approach, the
highest emitting source could be expected to achieve the floor 99 out
of 100 future tests when

[[Page 21294]]

operating under the same conditions as it did when the emissions data
were obtained. A floor that is expressed as a dioxin/furan emission
level would prevent sources from emitting at levels higher than the
(currently) worst-case source (actually, the worst-case performance
test result) currently emits. We specifically request comment on this
alternative MACT floor.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated use of an activated carbon bed (preceded by gas
reheating to above the dewpoint) as beyond-the-floor control for
dioxin/furan. Carbon beds can achieve greater than 99% reduction in
dioxin/furan emissions.\159\ We considered alternative beyond-the-floor
levels of 0.40 ng TEQ/dscm and 0.20 ng TEQ/dscm.
---------------------------------------------------------------------------

\159\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume V: Emissions Estimates and Engineering
Costs,'' March 2004, Chapter 4.
---------------------------------------------------------------------------

The incremental annualized cost of a beyond-the-floor emission
level of 0.40 ng TEQ/dscm would be $1.9 million and would provide an
incremental reduction in dioxin/furan emissions of 2.3 grams TEQ per
year, for a cost-effectiveness of $0.83 million per gram TEQ
removed.\160\ A beyond-the-floor emission level of 0.20 ng TEQ/dscm
would provide very little incremental emissions reduction--0.1 grams
TEQ per year--at additional costs. We evaluated nonair quality health
and environmental impacts and energy effects and determined that this
beyond-the-floor option would increase the amount of hazardous
wastewater generated by 210 tons per year, and would increase
electricity usage by 1.8 million kW-hours per year and natural gas
consumption by 96 trillion Btu per year.
---------------------------------------------------------------------------

\160\ Please note that, under the proposed floor level, sources
would not incur retrofit costs or achieve dioxin/furan emissions
reductions because they currently comply with the floor controls
under current RCRA regulations at 40 CFR 266.104.
---------------------------------------------------------------------------

We judge that the cost to achieve a beyond-the-floor standard of
0.40 ng TEQ/dscm is warranted given our special concern about dioxin/
furan. Dioxin/furan are some of the most toxic compounds known due to
their bioaccumulation potential and wide range of health effects,
including carcinogenesis, at exceedingly low doses. Exposure via
indirect pathways is a chief reason that Congress singled out dioxin/
furan for priority MACT control in CAA section 112(c)(6). See S. Rep.
No. 128, 101st Cong. 1st Sess. at 154-155. In addition, we note that
the beyond-the-floor emission level of 0.40 ng TEQ/dscm is consistent
with historically controlled levels under MACT for hazardous waste
incinerators and cement kilns, and Portland cement plants. See
Sec. Sec. 63.1203(a)(1), 63.1204(a)(1), and 63.1343(d)(3). Also, EPA
has determined previously in the 1999 Hazardous Waste Combustor MACT
final rule that dioxin/furan in the range of 0.40 ng TEQ/dscm or less
are necessary for the MACT standards to be considered generally
protective of human health under RCRA (using the 1985 cancer slope
factor), thereby eliminating the need for separate RCRA standards under
the authority of RCRA section 3005(c)(3) and 40 CFR 270.10(k). Finally,
we note that this decision is not inconsistent with EPA's decision not
to promulgate beyond-the-floor standards for dioxin/furan for hazardous
waste burning lightweight aggregate kilns, cement kilns, and
incinerators at cost-effectiveness values in the range of $530,000 to
$827,000 per additional gram of dioxin/furan TEQ removed. See 64 FR at
52892, 52876, and 52961. In those cases, EPA determined that
controlling dioxin/furan emissions from a level of 0.40 ng TEQ/dscm to
a beyond-the-floor level of 0.20 ng TEQ/dscm was not warranted because
dioxin/furan levels below 0.40 ng TEQ/dscm are generally considered to
be below the level of health risk concern.
For these reasons, we believe that proposing a beyond-the-floor
standard of 0.40 ng TEQ/dscm is warranted notwithstanding the nonair
quality health and environmental impacts and energy effects identified
above and costs of approximately $0.83 million per additional gram of
dioxin/furan TEQ removed. We specifically request comment on our
decision to propose this beyond-the-floor standard.
3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for new sources is the same as for existing sources
under the same rationale: compliance with the carbon monoxide/
hydrocarbon emission standard and compliance with the destruction and
removal efficiency standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
As for existing sources, we evaluated use of an activated carbon
bed as beyond-the-floor control for new sources to achieve an emission
level of 0.40 ng TEQ/dscm. We estimate that the incremental annualized
cost for a new hydrochloric acid production furnace with average gas
flowrate to reduce dioxin/furan emissions at the floor of 0.68 ng TEQ/
dscm \161\ to achieve a beyond-the-floor emission level of 0.40 ng TEQ/
dscm would be $0.15 million. These controls would provide an
incremental reduction in dioxin/furan emissions of 0.66 grams TEQ per
year, for a cost-effectiveness of $230,000 per gram TEQ removed. We
evaluated nonair quality health and environmental impacts and energy
effects and determined that, for a new source with an average gas
flowrate, this beyond-the-floor option would increase the amount of
hazardous wastewater generated by 9 tons per year, and would increase
electricity usage by 0.14 million kW-hours per year and natural gas
consumption by 9.2 trillion Btu per year.
---------------------------------------------------------------------------

\161\ We estimate beyond-the-floor control costs assuming a new
source emits the highest levels likely under floor control based on
compliance with the carbon monoxide and destruction and removal
efficiency standards.
---------------------------------------------------------------------------

[[Page 21295]]

B. What Is the Rationale for the Proposed Standards for Mercury,
Semivolatile Metals, and Low Volatile Metals?

We propose to require compliance with the total chlorine standard
as a surrogate for the mercury, semivolatile metals, and low volatile
metals standards.
As discussed above, hydrochloric acid production furnaces use wet
scrubbers to remove hydrochloric acid from combustion gases to produce
the hydrochloric acid product and to minimize residual emissions of
hydrochloric acid and chlorine gas. Wet scrubbers also remove metal
HAP, including mercury, from combustion gases. To minimize
contamination of hydrochloric acid product with metals, hydrochloric
acid production furnaces generally feed hazardous waste with low levels
of metal HAP. Moreover, the wet scrubbers used to recover the
hydrochloric acid product and minimize residual emissions of
hydrochloric acid and chlorine gas also control emissions of metal HAP
to very low levels. Based on emissions testing within the range of
normal emissions (i.e., not compliance test, maximum allowed
emissions), hydrochloric acid production furnaces emit mercury at
levels from 0.1 to 0.4 [mu]g/dscm, semivolatile metals at levels from
0.1 to 4.1 [mu]g/dscm, and low volatile metals at levels from 0.1 to 43
[mu]g/dscm.^{162, 163}
---------------------------------------------------------------------------

\162\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards,''
March 2004, Chapter 2.
\163\ Except that one source emitted 330 [mu]g/dscm low volatile
metals and 0.043 gr/dscf particulate matter during compliance
testing. This source apparently detuned the acid gas absorber and
other acid gas control equipment given that it achieved less than
99% system removal efficiency for total chlorine and had total
chlorine emissions of 500 ppmv. This source would not be allowed to
operate under these conditions under today's proposed rule: 14 ppmv
total chlorine emission limit, or 99.9927 system removal efficiency.
Thus, under the proposed rule, emissions of low volatile metals and
particulate matter would be substantially lower.
---------------------------------------------------------------------------

We also note that these sources emit low levels of particulate
matter. Compliance test, maximum allowable emissions of particulate
matter range from 0.001 to 0.013 gr/dscf.
Because wet scrubbers designed to recover the hydrochloric acid
product and control residual emissions of hydrogen chloride and
chlorine gas also control emissions of mercury, and semivolatile and
low volatile metals (including nonenumerated metals), use of MACT wet
scrubbers to comply with the proposed total chlorine standard discussed
below will also ensure MACT control of metal HAP. Accordingly, we
propose to use the total chlorine standard as a surrogate for the
mercury, semivolatile metals, and low volatile metals standards.

C. What Is the Rationale for the Proposed Standards for Total Chlorine?

The proposed standards for total chlorine are 14 ppmv or 99.9927
percent total chlorine system removal efficiency (SRE) for existing
sources and 1.2 ppmv or 99.99937 percent total chlorine SRE for new
sources. A source may elect to comply with either standard.
1. What Is the Rationale for the MACT Floor for Existing Sources?
The proposed MACT floor for existing sources is compliance with
either a total chlorine emission level of 14 ppmv or a total chlorine
SRE of 99.9927 percent.
Hydrochloric acid production furnaces use wet scrubbers to remove
hydrochloric acid from combustion gases to produce the hydrochloric
acid product and to minimize residual emissions of hydrochloric acid
and chlorine gas. We have compliance test, maximum allowable total
chlorine emissions data for all 17 hydrochloric acid production
furnaces. Total chlorine emissions range from 0.4 to 500 ppmv, and
total chlorine system removal efficiencies (SRE) range from 98.967 to
99.9995 percent.
As discussed in Section VI.C above, control of the feedrate of
chlorine in hazardous waste fed to the furnace is not an appropriate
MACT emission control technique because hydrochloric acid production
furnaces are designed to produce hydrochloric acid from chlorinated
feedstocks. Consequently, the approaches we normally use to identify
the best performing sources--SRE/Feed Approach or Emissions Approach--
are not appropriate because they directly or indirectly consider
chlorine feedrate. More simply, limiting feedrate means not producing
the intended product, a result inconsistent with MACT. See 2
Legislative History at 3352 (House Report) (``MACT is not intended to *
* * drive sources to the brink of shutdown''). To avoid this concern,
we identify a floor SRE, and provide an alternative floor as a total
chlorine emission limit based on floor SRE and the highest chlorine
feedrate for any source in the data base. By using the highest chlorine
feedrate to calculate the alternative total chlorine emission limit, we
ensure that feedrate control (i.e., nonproduction of product) is not a
factor in identifying the proposed MACT floor. The alternative total
chlorine emission limit would require a source that may not be
achieving floor SRE to achieve total chlorine emission levels no
greater than the level that would be emitted by any source achieving
floor SRE.
The floor SRE is 99.9927 percent. It is calculated from the five
best SREs, and considers emissions variability. Floor SRE is an SRE
that the average of the performing sources could be expected to achieve
in 99 of 100 future tests when operating under conditions identical to
the compliance test conditions during which the emissions data were
obtained. We estimate that this SRE is being achieved by 29% of sources.
The alternative floor emission limit is 14 ppmv, and is the
emission level that the source with the highest chlorine feedrate--
2.9E+8 [mu]g/dscm--would achieve when achieving 99.9927 percent SRE.
Approximately 24% of sources are achieving the alternative floor
levels, and these floor levels would reduce total chlorine emissions by
145 tons per year.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We evaluated improved design, operation, and maintenance of
existing scrubbers to achieve a beyond-the-floor emission level of 7
ppmv for total chlorine for existing sources, assuming a 50% reduction
in emissions from the floor level.
The national annualized compliance cost for hydrochloric acid
production furnaces to comply with this beyond-the-floor standard would
be $0.25 million, and emissions of total chlorine would be reduced by 3
tons per year. The cost-effectiveness of this beyond-the-floor standard
would be $76,000 per ton of total chlorine removed.
We evaluated nonair quality health and environmental impacts and
energy effects and determined that this beyond-the-floor option would
increase both the amount of hazardous wastewater generated and water
usage by approximately 82 million gallons per year and would increase
electricity usage by 0.34 million kW-hours per year. Generation of
nonwastewater hazardous waste would decrease by 7 tons per year.
Considering these impacts and cost-effectiveness as well, we conclude
that a beyond-the-floor standard for existing sources would not be
warranted.
For these reasons, we propose a floor total chlorine standard of 14
ppmv or 99.9927% SRE for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
The proposed MACT floor for new sources is compliance with either a
total chlorine emission level of 1.2 ppmv or

[[Page 21296]]

a total chlorine SRE of 99.99937 percent. We use the same rationale for
identifying alternative floors for new sources as discussed above in
the context of existing sources.
The new source floor SRE is the SRE that the single best performing
source (i.e, source with the best SRE) could be expected to achieve in
99 of 100 future tests when operating under conditions identical to the
compliance test conditions during which the emissions data were
obtained. The new source floor alternative emission limit is an
emission level that the source with the highest chlorine feedrate--
2.9E+8 [mu]g/dscm--would achieve when achieving 99.99937 percent SRE.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
We evaluated a beyond-the-floor standard for new sources of 0.60
ppmv based on achieving a 50 percent reduction in emissions by
improving the design/operation/maintenance of the wet scrubber. The
incremental annualized cost for a new solid fuel-fired boiler with
average gas flowrate to meet a beyond-the-floor level of 0.60 ppmv
would be approximately $0.15 million and would provide an incremental
reduction in total chlorine emissions of 0.07 tons per year, for a
cost-effectiveness of $2.1 million per ton of total chlorine removed.
We evaluated nonair quality health and environmental impacts and
energy effects and determined that, for a new source with average gas
flowrate, this beyond-the-floor option would increase both the amount
of hazardous wastewater generated and water usage by approximately 26
million gallons per year and would increase electricity usage by 0.25
million kW-hours per year. Considering these impacts and cost-
effectiveness as well, we conclude that a beyond-the-floor standard for
new sources would not be warranted.
For the reasons discussed above, we propose a total chlorine
standard of 1.2 ppmv or a total chlorine SRE of 99.99937 percent for
new sources.

D. What Is the Rationale for the Proposed Standards for Carbon Monoxide
or Hydrocarbons?

To control emissions of organic HAP, existing and new sources would
be required to comply with either a carbon monoxide standard of 100
ppmv or a hydrocarbon standard of 10 ppmv.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Hydrochloric acid production furnaces that burn hazardous waste are
currently subject to RCRA standards that require compliance with either
a carbon monoxide standard of 100 ppmv, or a hydrocarbon standard of 20
ppmv. Compliance is based on an hourly rolling average as measured with
a CEMS. See Sec. 266.104(a). All hydrochloric acid production furnaces
have elected to comply with the 100 ppmv carbon monoxide standard. We
propose floor standards of 100 ppmv for carbon monoxide or 10 ppmv for
hydrocarbons for the same reasons discussed above in the context of
liquid fuel-fired boilers.
There would be no incremental emission reductions associated with
these floors because sources are currently achieving the carbon
monoxide standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
Our considerations for beyond-the-floor standards for existing
hydrochloric acid production furnaces are identical to those discussed
above for existing liquid fuel-fired boilers. For the reasons discussed
above in the context of liquid fuel-fired boilers, we conclude that
beyond-the-floor standards for carbon monoxide and hydrocarbons for
existing hydrochloric acid production furnaces are not warranted.
3. What Is the Rationale for the MACT Floor for New Sources?
MACT floor for new sources would be the same as the floor for
existing sources--100 ppmv for carbon monoxide and 10 ppmv for
hydrocarbons--and based on the same rationale.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
Our considerations for beyond-the-floor standards for new
hydrochloric acid production furnaces are identical to those discussed
above for new liquid fuel-fired boilers. For the reasons discussed
above in the context of liquid fuel-fired boilers, we conclude that
beyond-the-floor standards for carbon monoxide and hydrocarbons for new
hydrochloric acid production furnaces are not warranted.

E. What Is the Rationale for the Proposed Standard for Destruction and
Removal Efficiency?

To control emissions of organic HAP, existing and new sources would
be required to comply with a destruction and removal efficiency (DRE)
of 99.99% for organic HAP. For sources burning hazardous wastes F020,
F021, F022, F023, F026, or F027, however, the DRE standard is 99.9999%
for organic HAP.
1. What Is the Rationale for the MACT Floor for Existing Sources?
Hydrochloric acid production furnaces that burn hazardous waste are
currently subject to RCRA DRE standards that require 99.99% destruction
of designated principal organic hazardous constituents (POHCs). For
sources that burn hazardous wastes F020, F021, F022, F023, F026, or
F027, however, the DRE standard is 99.9999% destruction of designated
POHCs. See Sec. 266.104(a).
The DRE standard helps ensure that a combustor is operating under
good combustion practices and thus minimizing emissions of organic HAP.
Under the MACT compliance regime, sources would designate POHCs that
are organic HAPs or that are surrogates for organic HAPs.
We propose to establish the RCRA DRE standard as the floor for
existing sources because it is a currently enforceable Federal
standard. There would be no incremental emission reductions associated
with this floor because sources are currently complying with the standard.
2. EPA's Evaluation of Beyond-the-Floor Standards for Existing Sources
We considered a beyond-the-floor level for DRE based on use of
better combustion practices but conclude that it may not be replicable
by the best performing sources nor duplicable by other sources given
that we cannot quantify better combustion practices. Moreover, we
cannot ensure that a higher DRE standard would significantly reduce
emissions of organic HAP given that DRE measures the destruction of
organic HAP present in the boiler feed rather than gross emissions of
organic HAP. Although a source's combustion practices may be adequate
to destroy particular organic HAP in the feed, other organic HAP may be
emitted as products of incomplete combustion.
For these reasons, and after considering nonair quality health and
environmental impacts and energy requirements, we are not proposing a
beyond-the-floor DRE standard for existing sources.
3. What Is the Rationale for the MACT Floor for New Sources?
We propose to establish the RCRA DRE standard as the floor for new
sources because it is a currently enforceable Federal standard.
4. EPA's Evaluation of Beyond-the-Floor Standards for New Sources
Using the same rationale as we used to consider a beyond-the-floor DRE

[[Continued on page 21297]]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]]
[[pp. 21297-21346]] National Emission Standards for Hazardous Air Pollutants:
Proposed Standards for Hazardous Air Pollutants for Hazardous Waste
Combustors (Phase I Final Replacement Standards and Phase II)
[[Continued from page 21296]]
[[Page 21297]]

XIII. What Is the Rationale for Proposing an Alternative Risk-Based
Standard for Total Chlorine in Lieu of the MACT Standard?

Under authority of CAA section 112(d)(4), we propose standard
procedures to allow you to establish a risk-based emission limit for
total chlorine in lieu of compliance with the section 112(d)(2) MACT
emission standard. See proposed Sec. 63.1215. The risk-based approach
would be applicable to all hazardous waste combustors except
hydrochloric acid production furnaces. Because we are proposing to use
the MACT standard for total chlorine as a surrogate to control metal
HAP for the hydrogen chloride production furnace source category, we
cannot allow any variance from the standard. For the other hazardous
waste combustor source categories, we are proposing the section
112(d)(4) standard as an alternative to the MACT standard. Sources
could choose which of these two standards they would prefer to apply.
The alternative risk-based emission limit for total chlorine would
be based on national exposure standards established by EPA that ensure
protection of public health with an ample margin of safety. The
standard would consist of a nationally-applicable, uniform algorithm
that would be used to establish site-specific emission limitations
based on site-specific input from each source choosing to use this
approach. Thus, these standards would provide a uniform level of risk
reduction, consistent with the requirement of section 112(d)(4) that
EPA establish ``emission standards'', i.e., a requirement established
by EPA which limits quantity, rate or concentration of air emissions
(see CAA section 302(k)).
We also request comment on an alternative approach to implement
section 112(d)(4) for cement kilns in which we establish a national
risk-based emission standard for total chlorine that would be
applicable to all cement kilns. Under this approach, EPA would issue a
single total chlorine emission standard using an emission level that
meets our national exposure standards if each cement kiln were to emit
at that level.
We believe that most hazardous waste combustors are likely to
consider establishing risk-based standards for total chlorine because
the MACT standards proposed today are more stringent, and in some cases
substantially more stringent, than currently applicable standards
(e.g., the total chlorine standard for incinerators is currently 77
ppmv while we propose today a MACT standard of 1.4 ppmv).

A. What Is the Legal Authority To Establish Risk-Based Standards?

Under the authority of section 112(d)(4), the Administrator may
establish emission standards based on risk, in lieu of the technology-
based MACT standards, when regulating HAP for which health threshold
levels have been established. Under section 112(d)(4), Congress gave
EPA the discretion to consider the health threshold of any HAP and to
use that health threshold, with an ample margin of safety, to set
emission standards for the source category or subcategory. In the
legislative history accompanying this provision, the Senate Report stated,

``To avoid expenditures by regulated entities that secure no
public health or environmental benefit, the Administrator is given
discretionary authority to consider the evidence for a health
threshold higher than MACT at the time the standard is under review.
The Administrator is not required to take such factors into account;
that would jeopardize the standard-setting schedule imposed under
this section with the kind of lengthy study and debate that has
crippled the current program. But where health thresholds are well
established, for instance in the case of ammonia, and the pollutant
presents no risk of other adverse health effects, the Administrator
may use the threshold with an ample margin of safety (and not
considering cost) to set emissions limitations for sources in the
category or subcategory.'' (S. Rep. No. 228, 101st Cong. 1st Sess.
at 171 (1989); see also id. at 175-176 (1989).)

EPA has previously used section 112(d)(4) authority in the
Industrial Boiler and Process Heater MACT Final Rule signed Feb. 26,
2004, the Pulp and Paper MACT Phase II (66 FR 3180, January 12, 2001)
and the Lime Manufacturing MACT (69 FR 394, January 5, 2004), and has
proposed to use it in a different manner in several other MACT
rulemakings (e.g., the Reciprocating Internal Combustion Engine MACT
(67 FR 77830, December 19, 2002).\164\ The approach we propose today is
nearly identical to the approach EPA recently adopted for the
Industrial Boiler and Process Heater MACT source category, which allows
a source to establish a site-specific risk-based emission limit for
threshold HAP using prescribed procedures. This approach differs from
the previous MACT rules where EPA simply determined, on a national
basis, what level of exposure from each source in the category would be
protective of public health with an ample margin of safety, and did not
pose significant adverse environmental impacts. This previous approach
resulted in a determination that no standard was necessary because no
source in the category could exceed such a risk-based standard. Today's
proposal varies in that the level of protection afforded by the
standard is uniform, but the limits for individual sources differ due
to site-specific factors. As explained later in this section of the
preamble, EPA is, however, also considering for cement kilns applying
the single national standard approach adopted in earlier rules.
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\164\ The Agency also proposed to use Section 112(d)(4)
authority in two other MACT rulemakings--the Combustion Turbine MACT
(68 FR 1888, January 14, 2003), and the Chlorine Production MACT (67
FR 44671)--but determined that MACT standards for those source
categories are not warranted and delisted the source categories from
the section 112(c) list of major sources pursuant to the authority
in section 112(c)(9).
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B. What Is the Rationale for the National Exposure Standards?

We identify as national exposure standards threshold levels that
are protective of human health from both chronic and acute exposure. In
addition, because EPA has discretion whether or not to promulgate risk-
based standards pursuant to section 112(d)(4), we would not allow an
alternative standard where emission levels may result in adverse
environmental effects that would otherwise be reduced or eliminated. We
would not issue the alternative standard even though it may be shown
that emissions do not approach or exceed levels requisite to protect
public health with an ample margin of safety because we believe the
statute requires that we consider effects on terrestrial animals,
plants, and aquatic ecosystems in addition to public health in
establishing a standard pursuant to section 112(d)(4). See S. Rep. 228
at 176: ``Employing a health threshold or safety level rather than the
MACT criteria to set standards shall not result in adverse
environmental effects which would otherwise be reduced or eliminated.''
1. What Are the Human Health Threshold Levels?
a. Chronic Exposure. Hydrogen chloride is corrosive to the eyes,
skin, and mucous membranes. Chronic exposure may cause gastritis,
bronchitis, dermatitis, and dental discoloration and erosion. Chronic
exposure to chlorine gas can cause respiratory effects

[[Page 21298]]

including eye and throat irritation and airflow obstruction. See
discussion in Part One, Section I.E of this preamble.
Given that neither hydrogen chloride nor chlorine gas is known to
produce a carcinogenic response,\165\ we use reference air
concentrations (RfC) to assess the likelihood of non-cancer health
effects in humans. The RfC is an estimate of a continuous inhalation
exposure to the human population, including sensitive subgroups, that
is likely to be without an appreciable risk of deleterious effects over
a lifetime. We use an RfC for hydrogen chloride of 20 [mu]g/m\3\, as
presented in EPA's Integrated Risk Information System (IRIS). We
propose to use an RfC for chlorine gas of 0.2 [mu]g/m\3\ based on a
provisional assessment prepared by EPA on inhalation hazards from
chlorine.\166\ This is the same as the value for chlorine used by the
State of California's Office of Environmental Health Hazard Assessment,
which they refer to as a chronic ``Reference Exposure Level'' (REL).
Because RfCs can change over time based on new information, the rule
would require you to use the current RfC value found at
http://epa.gov/ttn/atw/toxsource/summary.html.

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\165\ EPA conducted an assessment of the carcinogenicity of
chlorine gas and concluded that it is not likely to be a human
carcinogen (see EPA's June 22, 1999 Risk Assessment Issue Paper for
Derivation of a Provisional Chronic Inhalation RfC for Chlorine,
p.12). The International Agency for Research on Cancer (IARC)
concluded that hydrochloric acid is not classifiable as to its
carcinogenicity to humans (see IARC Monographs, Vol. 54:
Occupational Exposures to Mists and Vapours from Strong Inorganic
Acids; and Other Industrial Chemicals (1992) p.189).
\166\ See EPA's externally peer-reviewed ``Risk Assessment Issue
Paper for Derivation of a Provisional Chronic Inhalation RfC for
Chlorine'' (June 22, 1999) that can be found in the docket for
today's proposal.
---------------------------------------------------------------------------

We considered how to account for the fact that chlorine gas
photolyzes in the atmosphere in bright sunlight to chlorine ions and
then quickly reacts with hydrogen or methane to form hydrogen chloride.
The half-life of chlorine due to photolysis in bright sunlight is
estimated to be 10 minutes.\167\ Nonetheless, this is generally
sufficient time for the plume to reach nearby ground-level receptors
without significant transformation. In addition, such transformation is
possible only a portion of the time. Photolysis does not occur at night
and is reduced on overcast or cloudy days. Generally speaking, the rate
of photolysis depends on the particular wavelength and intensity of
solar radiation reaching the earth's surface which varies greatly
depending on the solar angle which changes with the time of day, the
season of the year, and the latitude at a given location. While the
ideal approach would be explicit modeling of photolysis rates as a
function of solar insolation, sky conditions, absorption cross-section,
quantum yield, and subsequent transformation to hydrogen chloride, to
our knowledge no such regulatory air dispersion model currently exists.
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\167\ As determined by a modeling analysis done by the Air
Pollution Research Center at the University of California at
Riverside, as reported in a California Air Resources Board fact
sheet, ``Toxic Air Contaminant Identification List Summaries--ARB/
SSD/SES,'' p. 231, September 1997. See also
http://www.arb.ca.gov/toxics/tac/factshts/chlorine.pdf.

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Because it is reasonable to believe that receptors will be exposed
to chlorine gas before appreciable transformation occurs due to the
variability and complexity of the transformation and the fact that
chlorine gas is considerably more toxic than hydrogen chloride, we
conclude that, for the purpose of protection of public health, it is
prudent to assume that chlorine gas is not transformed to hydrogen
chloride.
b. Acute Threshold Levels. Short-term exposure to hydrogen chloride
may cause eye, nose, and respiratory tract irritation and inflamation
and pulmonary edema. Short-term exposure to high levels of chlorine gas
can result in chest pain, vomiting, toxic pneumonitis, and pulmonary
edema. At lower levels, chlorine gas is a potent irritant to the eyes,
the upper respiratory tract, and lungs. See Part One, Section I.E.
Please note that, although we discuss here how we would consider acute
exposure, we conclude below that you need not assess acute exposure to
establish an emission limit for total chlorine. See discussion in
Section B.2.e.
To assess effects from acute exposure, we would use the acute
exposure guideline level (AEGL). AEGL toxicity values are estimates of
adverse health effects due to a single exposure lasting 8 hours or
less. Consensus toxicity values for effects of acute exposures have
been developed by several different organizations. EPA, in conjunction
with the National Research Council and National Academy of Sciences, is
in the process of setting acute exposure guideline levels. A national
advisory committee organized by EPA has developed AEGLs for priority
chemicals for 10-minute, 30-minute, 1-hour, 4-hour, and 8-hour airborne
exposures. They have also determined for each exposure duration the
levels of these chemicals that will protect against notable discomfort
(AEGL-1), serious effects (AEGL-2), and life-threatening effects or
death (AEGL-3).\168\ To be protective of public health, we propose to
use the AEGL-1 values to assess acute exposure: 2.7 mg/m\3\ (1.8 ppm)
for hydrogen chloride, and 1.4 mg/m\3\ (0.5 ppm) for chlorine gas.\169\
Airborne concentrations of a substance above the AEGL-1 could cause
notable discomfort, irritation, or certain asymptomatic nonsensory
effects in the general population, including susceptible individuals.
Please note, however, that airborne concentrations below the AEGL-1
could produce mild odor, taste, or other sensory irritations. Effects
above the AEGL-1 (but below the AEGL-2) are not disabling and are
transient and reversible upon cessation of exposure.
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\168\ The full definitions of the AEGL values are more nuanced.
AEGL 1: The airborne concentration of a substance above which it is
predicted that the general population, including susceptible
individuals, could experience notable discomfort, irritation, or
certain asymptomatic nonsensory effects. However, the effects are
not disabling and are transient and reversible upon cessation of
exposure. AEGL 2: The airborne concentration of a substance above
which it is predicted that the general population, including
susceptible individuals, could experience irreversible or other
serious, long-lasting adverse health effects or an impaired ability
to escape. AEGL 3: The airborne concentration of a substance above
which it is predicted that the general population, including
susceptible individuals, could experience life-threatening health
effects or death.
\169\ For hydrogen chloride and chlorine gas (individually), the
AEGL-1 values for 10-minute, 30-minute, 1-hour, and 8-hour exposures
are the same. Therefore, when comparing predicted ambient levels of
exposure to the AEGL-1 value, we believe it is reasonable to
evaluate maximum 1-hour ground level concentrations.
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2. What Exposures Would You Be Required to Assess?
We discuss below the following issues: (1) Use of the Hazard Index
to assess exposure to both hydrogen chloride and chlorine gas; (2)
exposure to emissions of respiratory irritant HAP other than hydrogen
chloride and chlorine gas; (3) exposure to emissions of respiratory
irritant HAP from collocated sources; (4) exposure to ambient
background levels of respiratory irritant HAP; and (5) our conclusion
that acute exposure need not be assessed to establish emission limits
because the Hazard Index for chronic exposure is expected to be higher
in all situations.
a. Hazard Index. Noncancer risk assessments typically use a metric
called the Hazard Quotient (HQ) to assess risks of exposures to
noncarcinogens. The HQ is the ratio of a receptor's potential exposure
(or modeled concentration) to the health reference value or threshold
level (e.g., RfC or AEGL) for an individual pollutant. HQ values less
than 1.0 indicate that exposures are below the

[[Page 21299]]

health reference value or threshold level and, therefore, that such
exposures are without appreciable risk of adverse effects in the
exposed population. HQ values above 1 do not necessarily imply that
adverse effects will occur, but that the likelihood of such effects in
a given population increases as HQ values exceed 1.0.\170\
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\170\ See US EPA Glossary of Key Terms for National Air Toxics
Assessment, at http://www.epa.gov/ttn/atw/nata/gloss1.html.

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When the risk of noncancer effects from exposure to more than one
pollutant to the same target organ must be assessed, the effects are
generally considered to be additive and the HQ values for each
pollutant are summed to form an analogous metric called the Hazard
Index (HI). Assuming additivity, HI values less than 1.0 indicate that
exposures to the mixtures are likely to be without appreciable risk of
adverse effects in the exposed population. HI values above 1.0 do not
necessarily imply that adverse effects from exposure to the mixture
will occur, but that the likelihood of such effects in a given
population increases as HI values exceed 1.0.
For purposes of establishing risk-based emission limits for total
chlorine, we propose to allow a maximum HI value of not greater than
1.0.
b. Exposure to Emissions of HAP other than Hydrogen Chloride and
Chlorine Gas that Have a Common Mechanism of Action. We have identified
in the table below 40 HAP that are respiratory irritants, including
hydrogen chloride and chlorine gas. Because these HAP have a common
mechanism of action, we must determine whether exposure to these HAP
must be considered when determining that the HI is less than or equal
to 1.0.
Respiratory Irritant HAP
1,2-Epoxybutane
1,3-dichloropropene
2,4-Toluene diisocyanate
2-Chloroacetophenone
Acetaldehyde
Acrolein
Acrylic acid
Acrylonitrile
Antimony
Beryllium
Bis(2-ethylhexyl)phthalate
Chlorine
Chloroprene
Chromium
Cobalt
Diethanolamine
Epichlorohydrin
Ethylene glycol
Formaldehyde
Hexachlorocyclopentadiene
Hexamethylene 1,6-diisocyanate
Hydrochloric acid
Maleic anhydride
Methyl bromide
Methyl isocyanate
Methyl methacrylate
Methylene diphenyl diisocyanate
N-hexane
Naphthalene
Nickel
Nitrobenzene
Phosgene
Phthalic anhydride
Propylene dichloride
Propylene oxide
Styrene oxide
Titanium tetrachloride
Toluene
Triethylamine
Vinyl acetate

In making this determination, we would consider only those
respiratory irritants that are HAP (as opposed to also considering
respiratory irritants that are criteria pollutants) not only because
section 112 deals with control of emissions of HAP, but also because
ambient levels of criteria pollutants that have a common mechanism of
action with hydrogen chloride and chlorine gas (e.g., SOX,
NOX, PM, ozone) are controlled through the applicable State
Implementation Plans demonstrating compliance with the National Ambient
Air Quality Standards for these pollutants.
In addition to hydrogen chloride and chlorine gas, several of the
respiratory irritant HAP listed in the table above may be emitted by
hazardous waste combustors, including the metals antimony trioxide,
beryllium, chromium (VI), cobalt, and nickel, and the organic compounds
Bis(2-ethylhexyl)phthalate, formaldehyde, napthalene, and toluene.\171\
We do not believe, however, that these respiratory irritant HAP would
be emitted by hazardous waste combustors at levels that would result in
significant Hazard Quotient values. Beryllium and chromium would be
controlled by emission standards for low volatile metals and the
remaining metal HAP would be controlled by a particulate matter
standard. Emissions of the respiratory irritant organic HAP would be
controlled to trace levels by the MACT standards for carbon monoxide or
hydrocarbons and destruction and removal efficiency (DRE). Accordingly,
we propose to require you to quantify and assess emissions from the
hazardous waste combustor of hydrogen chloride and chlorine gas only;
you would not be required to account for these other respiratory
irritant HAP because they would not contribute substantially to the
Hazard Index.
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\171\ Betty Willis, et al., Agency for Toxic Substances and
Disease Registry, U.S. Department of Health and Human Services,
``Public Health Reviews of Hazardous Waste Thermal Treatment
Technologies: A Guidance Manual for Public Health Assessors,'' March
2002, Table 4.
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c. Exposure to Emissions of Respiratory Irritant HAP from
Collocated Sources. You would be required to account for exposure to
emissions of hydrogen chloride and chlorine gas from all on-site
hazardous waste combustors subject to subpart EEE, part 63. EPA will
address exposure to emissions of respiratory irritant HAP from other
sources that may be collocated with a hazardous waste combustor--for
example, process vents and fossil fuel boilers--under the residual risk
requirements of section 112(f) for both hazardous waste combustors and
(potentially) other MACT source categories. See A Legislative History
of the Clean Air Act Amendments of 1990 (Senate Print 103-38, 103d
Cong. 1st sess.) vol. 1 at 868-69 (floor statement of Sen. Durenberger
(Senate floor manager for section 112) during debate on the Conference
Report, indicating that EPA is obligated to consider ``combined risks
of all sources that are collocated with such sources within the same
major source'' but going on to state that the determination of ample
margin of safety from emissions from all collocated sources need not
occur at the same time, but rather can be spread out over the course of
the residual risk determination process for all major sources.
d. Exposure to Ambient Background Levels of Respiratory Irritant
HAP. Background levels of respiratory irritant HAP attributable to
emissions from off-site sources would not be considered when
establishing risk-based limits for total chlorine under section
112(d)(4). Rather, these background levels will be addressed (as may be
necessary) through other CAA programs such as the urban air toxics program.
e. Acute Exposure Need Not Be Assessed. We have determined that you
need not assess acute exposure to establish an emission limit for total
chlorine. You would not be required to model maximum 1-hour average
off-site ground level concentrations to calculate a Hazard Index (HI)
based on acute exposure for purposes of establishing an emission limit
for total chlorine. We conclude that the chronic exposure Hazard Index
(HI) for the hazardous waste combustor(s) would always exceed the acute
exposure HI. Thus, the emission limit for total chlorine based on
chronic exposure would always be more stringent than the limit based on

[[Page 21300]]

acute exposure. As an example, the Cement Kiln Recycling Coalition
evaluated both chronic and acute exposure to hydrogen chloride and
chlorine gas for the 14 cement facilities that burn hazardous
waste.\172\ In all cases, the chronic HI exceeded the acute HI. In
addition, we determined that the Hazard Quotient (HQ) for chronic
exposure was always higher than the HQ for acute exposure for the HAP
we evaluated in the risk assessment we used to support the 1999 Final
MACT Rule for hazardous waste combustors.\173\
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\172\ See Trinity Consultants, ``Analysis of HCl/Cl2 Emissions
from Cement Kilns for 112(d)(4) Consideration in the HWC MACT
Replacement Standards,'' September 17, 2003.
\173\ See USEPA, ``Human Health and Ecological Risk Assessment
Support to the Development of Technical Standards for Emissions from
Combustion Units Burning Hazardous Wastes: Background Document,''
July 1999.
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Not requiring an acute exposure analysis reduces the burden on both
the regulated community and regulatory officials to develop and review
an analysis that would be superseded by the chronic exposure analysis
when establishing an emission limit for total chlorine.
Please note that this discussion relates to evaluating acute
exposure in establishing an emission limit for total chlorine. Although
we conclude that the chronic exposure Hazard Index would always be
higher than the acute exposure Hazard Index, and thus would be the
basis for the total chlorine emission rate limit, this relates to acute
versus chronic exposure to a constant, maximum average (e.g., a maximum
annual average) emission rate of total chlorine from a hazardous waste
combustor. Acute exposure must be considered, however, when
establishing operating requirements (e.g., feedrate limit for total
chlorine and chloride) to ensure that short-term emissions do not
result in an acute exposure Hazard Index of 1.0 or greater even though
long-term (e.g., annual average) emissions do not exceed the limit. See
discussion in Section G.1 below.
3. Does the Proposed Approach Ensure an Ample Margin of Safety?
Section 112(d)(4) allows EPA to develop risk-based standards for
HAP ``for which a health threshold has been established'', and the
resulting standard is to provide an ``ample margin of safety.'' The
``ample margin of safety'' standard, at least as applied to
nonthreshold pollutants, typically connotes a two-step process (based
on the standard first announced in the so-called Vinyl Chloride
decision (NRDC v. EPA, 824 F. 2d at 1146 (D.C. Cir. 1987)), whereby EPA
``first [determines] * * * a `safe' or `acceptable' level of risk
considering only health factors, followed by a second step to set a
standard that provides an `ample margin of safety', in which costs,
feasibility, and other relevant factors in addition to health may be
considered.'' 54 FR at 38045. It is not clear that Congress intended
this analysis to apply to section 112(d)(4) standards, since the
principal legislative history to the provision indicates that costs are
not to be considered in setting standards under section 112(d)(4) (S.
Rep. 228 at 173), whereas cost normally is a relevant consideration in
the second part of the ample margin of safety process, as described
above. Further, if issues of feasibility, cost, and other non-health
factors are to be taken into account in establishing section 112(d)(4)
standards, it would be exceedingly difficult, if not practically
impossible, to do so on a site-specific basis, undermining the approach
we are proposing here. Nor is it clear that the two-step approach is
necessarily warranted when considering threshold pollutants, since
there is greater certainty regarding levels at which adverse health
effects occur. See Vinyl Chloride, 824 F. 2d at 1165 n. 11.\174\
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\174\ Indeed, using the classic two-step approach to ``ample
margin of safety'' could result in the same standards we are
proposing as MACT for HCl and Cl2 for all of the affected source
categories (if one assumes that all of the standards would be below
protective risk-based levels for all sources), since we believe that
the proposed technology-based standards would be justifiable based
on considerations of technical feasibility and cost, and so would
provide a reasonable margin of safety beyond the risk-based level
considered protective.
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We specifically request comment on how to ensure that the emission
limits calculated using the health threshold values (e.g., RfCs and
AEGL-1 values), and after considering emissions of respiratory irritant
HAP from collocated hazardous waste combustors, achieve an ample margin
of safety.
4. How Are Effects on Terrestrial Animals Addressed?
We believe the RfC values for hydrogen chloride and chlorine gas
should be generally protective for chronic effects in most, if not all,
fauna. We note that the RfC values are based on animal studies.
Although the AEGL-1 values for acute exposure are based on human data,
we nonetheless expect that they too would be generally protective of
most fauna, absent information to the contrary.
5. How Are Effects on Plants Addressed?
EPA has not established ecotoxicity values that are protective of
vegetation. Nonetheless, for the reasons discussed below we do not
believe that ambient concentrations of hydrogen chloride and chlorine
gas that meet the human health threshold values discussed above will
pose adverse effects on plants.
As discussed in the preamble to the Lime Manufacturing NESHAP
proposed rule (67 FR 78056),\175\ chronic exposure to about 600 [mu]g/
m³ can be expected to result in discernible effects,
depending on the plant species. Effects of acute, 20-minute exposures
of 6,500 to 27,000 [mu]g/m³ include leaf injury and decrease
in chlorophyll levels in various species. The hydrogen chloride RfC of
20 [mu]g/m³ is well below the 600 [mu]g/m³ effect
level, and the AEGL-1 value for hydrogen chloride of 2,700 [mu]g/
m³ is far below the 6500 [mu]g/m³ acute effect
level. Therefore, no adverse exposure effects are anticipated.
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\175\ EPA published the final rule at 69 FR 394, January 5, 2004.
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We specifically request additional information on ecotoxicity for
both acute and chronic exposure of vegetation to hydrogen chloride and
chlorine gas.

C. How Would You Determine if Your Total Chlorine Emission Rate Meets
the Eligibility Requirements Defined by the National Exposure Standards?

Under the risk-based approach to establish an alternative to the
MACT standard for your total chlorine emission limit, you would have to
demonstrate that emissions of total chlorine from on-site hazardous
waste combustors result in exposure to the actual most-exposed
individual residing off site of a Hazard Index of less than or equal to
1.0. (Put another way, we are proposing to establish this level of risk
as the national emission limitation, with the rule further establishing
the mechanisms by which this demonstration can be made, such
demonstrations yielding a site-specific limit for total chlorine.)
\176\ The rule would also establish two ways by which you could make
this demonstration: by a look-up table analysis or by a site-specific
compliance demonstration (as explained below). The look-up table is
much simpler to use, but establishes emission rates that are quite
conservative because there are few site-specific parameters considered and

[[Page 21301]]

therefore the model's default assumptions are conservative. If you
elect not to comply with those conservative emission rates, you may
perform a site-specific compliance demonstration.
---------------------------------------------------------------------------

\176\ Rather than establishing emission rate limits for hydrogen
chloride and chlorine gas, or for total chlorine, for each
combustor, you would actually establish an HCl-equivalent emission
rate limit for each combustor, as discussed below in the text.
---------------------------------------------------------------------------

The look-up table identifies the total chlorine emission limit in
terms of a toxicity-weighted HCl-equivalent emission rate. Under the
site-specific compliance demonstration alternative, the total chlorine
limit would also be expressed as a toxicity weighted HCl-equivalent
emission rate even though you would model emissions of hydrogen
chloride and chlorine gas from each on-site hazardous waste combustor.
We define the toxicity-weighted HCl-equivalent emission rate below.
1. Toxicity-Weighted HCl-Equivalent Emission Rates
Although the MACT emission standards for total chlorine are
expressed as a stack gas emission concentration--ppmv--we must use an
emission rate (e.g., lb/hr) format for risk-based standards. This is
because health and environmental risk is related to the mass rate of
emissions over time.
In addition, we propose to use a toxicity-weighted HCl-equivalent
emission rate (HCl-equivalents) as the metric for the combined
emissions of hydrogen chloride and chlorine gas. The HCl-equivalent
emission rate considers the RfCs of hydrogen chloride and chlorine gas
when calculating the combined emission rate according to this equation:
ERdtw = [Sigma](ERi x (RfCHC1/
RfCi))

where:

ERtw is the HC1-equivalent emission rate, lb/hr
ERi is the emission rate of HAP i in lbs/hr
RfCi is the reference concentration of HAP i
RfCHC1 is the reference concentration of HCl
Expressing the risk-based emission limit as HCl-equivalents enables
you to use the equation to apportion the emission rate limit between
hydrogen chloride and chlorine gas as you choose. Thus, you need to be
concerned with ensuring compliance with the HCl-equivalent emission
rate only, rather than with emission rates for hydrogen chloride and
chlorine gas individually.
Under the look-up table analysis discussed below, you would use the
hydrogen chloride and chlorine gas emission rates you choose for each
on-site hazardous waste combustor to calculate the HCl-equivalent
emission rate for the combustor. You would sum the HCl-equivalent
emission rates for your hazardous waste combustors. If you elect to use
the site-specific compliance demonstration to document eligibility, you
would model emission rates of hydrogen chloride and chlorine gas that
you choose for each on-site hazardous waste combustor to document that
the facility Hazard Index is less than or equal to 1.0. You would then
use the hydrogen chloride and chlorine gas emission rates you model to
establish an HCl-equivalent emission rate limit for each combustor.
2. How Would You Conduct a Look-Up Table Analysis?
You would sum the HCl-equivalent rates for all combustors, and
compare the sum to the appropriate allowable emission rate in Table 1
of proposed Sec. 63.1215. Emission rates are provided as a function of
stack height and distance to the nearest property boundary. If you have
more than one hazardous waste combustor at your facility, you would use
the average value for stack height (i.e., the averaged stack heights of
the different hazardous waste combustors at your facility), and the
minimum distance between any hazardous waste combustor stack and the
property boundary.\177\
---------------------------------------------------------------------------

\177\ HCl production furnaces are not eligible for the risk-
based total chlorine emission limits because we are proposing that
the MACT standard for total chlorine would be used as a surrogate to
control metal HAP. Nonetheless, if you operate an HCl production
furnace at a facility where you would establish risk-based emission
limits for total chlorine for other hazardous waste combustors, you
would account for total chlorine emissions from the HCl production
furnace in your risk-based eligibility demonstration for the other
combustors. If, for example, you use the look-up table to
demonstrate eligibility, you would include the stack height of the
HCl production furnace in the calculation of average stack height
for your combustors, and you would consider whether the HCl
production furnace stack is the closest hazardous waste combustor
stack to the property boundary.
---------------------------------------------------------------------------

If one or both of these values for stack height and distance to
nearest property boundary do not match the exact values in the look-up
table, you would use the next lowest table value. This would ensure
that the HCl-equivalent emission rate limits are protective.
You would not be eligible for the look-up table analysis if your
facility is located in complex terrain because the plume dispersion
models used to calculate the emission rates are not applicable to
sources in complex terrain.
You would be eligible to comply with the risk-based alternative
HCl-equivalent emission rate limits you calculate for each combustor if
the facility HCl-equivalent emission rate limit (i.e., the sum of the
HCl-equivalent emission rates for all hazardous waste combustors) does
not exceed the appropriate value specified in the look-up table. Please
note, however, that we also propose to cap the HCl-equivalent emission
rate limits for incinerators, cement kilns, and lightweight aggregate
kilns at a level that ensures that the current total chlorine emission
standards are not exceeded. See discussion below in Section D.
Please note that the emission rates provided in Table 1 are
different from those provided for industrial boilers in the Industrial
Boiler and Process Heater MACT rule recently promulgated. This is
because the key parameters used by the SCREEN3 atmospheric dispersion
model to predict the normalized air concentrations that EPA used to
establish HCl-equivalent emission rates as a function of stack height
and distance to property boundary for industrial boilers--stack
diameter, stack exit gas velocity, and stack exit gas temperature--are
substantially different for hazardous waste burning incinerators,
cement kilns, and lightweight aggregate kilns. Thus, the maximum HCl-
equivalent emission rates for hazardous waste combustors would
generally be lower than those EPA established for industrial boilers.
To ensure that the HCl-equivalent emission rate limits in a look-up
table analysis for hazardous waste combustors would not result in a
Hazard Index of more than 1.0, we propose to establish limits based on
the maximum annual average normalized air concentrations in U.S. EPA,
``A Tiered Modeling Approach for Assessing the Risk Due to Sources of
Hazardous Air Pollutants,'' March 1992, Table 1. Those normalized air
concentrations are based on conservative simulations of toxic pollutant
sources with Gaussian plume dispersion models. The simulations are
conservative regarding factors such as meteorology, building downwash,
plume rise, etc.
We specifically request comment on whether the HCl-equivalent
emission rates in Table 1 are too conservative and thus have limited
utility because they apply to all hazardous waste combustors
generically. Alternatively, we could establish less conservative
emission rates in look-up tables specific to various classes of
hazardous waste combustors (e.g., cement kilns, incinerators) that have
similar stack properties that affect predicted emissions. We request
comment on whether industry stakeholders would be likely to use the
proposed look-up table eligibility demonstration or revised

[[Page 21302]]

look-up tables tailored to specific classes of hazardous waste
combustors, in lieu of the site-specific compliance eligibility
demonstration.
3. How Would You Conduct a Site-Specific Compliance Demonstration?
If you fail to demonstrate that your facility is able to comply
with the alternative risk-based emission limit using the look-up table
approach, you may choose to perform a site-specific compliance
demonstration. We are proposing that you may use any scientifically-
accepted peer-reviewed risk assessment methodology for your site-
specific compliance demonstration. An example of one approach for
performing the demonstration for air toxics can be found in the EPA's
``Air Toxics Risk Assessment Reference Library, Volume 2, Site-Specific
Risk Assessment Technical Resource Document,'', which may be obtained
through the EPA's Air Toxics Web site at http://www.epa.gov/ttn/atw.
Your facility would be eligible for the alternative risk-based
total chlorine emission limit if your site-specific compliance
demonstration shows that the maximum Hazard Index for hydrogen chloride
and chlorine gas emissions from all on-site hazardous waste combustors
at a location where people live (i.e., the maximum actual most exposed
individual) is less than or equal to 1.0, rounded to the nearest tenths
decimal place (0.1).\178\ You would estimate long-term inhalation
exposures for this individual most exposed to the facility's emissions
through the estimation of annual or multi-year average ambient
concentrations. You would use site-specific, quality-assured data
wherever possible, and health-protective default assumptions wherever
site-specific data are not available. You would document the data and
methods used for the assessment so that it is transparent and can be
reproduced by an experienced risk assessor and emissions measurement
expert.
---------------------------------------------------------------------------

\178\ When calculating Hazard Index values, the final HI value
should be rounded to one decimal place given the uncertainties in
the analyses. For example, an HI calculated to be 0.94 would be
presented as 0.9, while an HI calculated to be 0.96 would be
presented as 1.0 (which would pass the eligibility demonstration).
Intermediate calculations should use as many significant figures as
appropriate.
---------------------------------------------------------------------------

Your site-specific compliance demonstration need not assume any
attenuation of exposure concentrations due to the penetration of
outdoor pollutants into indoor exposure areas. In addition, we are
proposing that the demonstration need not assume any reaction or
deposition of hydrogen chloride and chlorine gas from the emission
point to the point of exposure. In particular, you would assume that
chlorine gas is not photolyzed to hydrogen chloride, as discussed in
Section B.1 above.
If your site-specific compliance demonstration documents that the
maximum Hazard Index from your hazardous waste combustors is less than
or equal to 1.0, you would establish a maximum HCl-equivalent emission
rate limit for each combustor using the hydrogen chloride and chlorine
gas emission rates you modeled in the site-specific compliance
demonstration. Please note, however, that we also propose to cap the
HCl-equivalent emission rate limits for incinerators, cement kilns, and
lightweight aggregate kilns at a level that ensures that the current
total chlorine emission standards are not exceeded. See discussion
below in Section D.

D. What Is the Rationale for Caps on the Risk-Based Emission Limits?

The HCl-equivalent emission rate limits would be capped for
incinerators, cement kilns, and lightweight aggregate kilns at a level
that ensures total chlorine emissions do not exceed the interim
standards provided by Sec. Sec. 63.1203, 63.1204, and 63.1205. These
caps on the risk-based emission limits would ensure that emission
levels do not increase above the emission levels that sources are
currently required to achieve, thus precluding ``back-sliding.'' Given
the discretionary nature of section 112(d)(4), and the general purpose
of the section 112(d) standard-setting process to lock-in performance
of current emission control technology, we think it appropriate to
invoke the provision in a manner that does not result in emission
increases over current regulatory levels.
We considered whether to propose emission caps for boilers at the
levels allowed by the RCRA emission standards under Sec. 266.107 but
conclude that this would be inappropriate. This is because the RCRA
emission standards are also risk-based standards but are based on risk
criteria that we considered appropriate in 1987 when we proposed those
rules. The risk criteria we propose today are substantially different
from those used to implement Sec. 266.107. For example, the RfC for
hydrogen chloride is higher now while the RfC for chlorine gas is
lower. In addition, we considered a Hazard Index of 0.25 acceptable
under the RCRA rule, while we propose today a Hazard Index limit of
less than or equal to 1.0. Because the risk criteria for the current
RCRA rules are substantially different from the risk criteria we
propose today for invoking Section 112(d)(4), we do not believe it is
appropriate to use the RCRA standards as a cap for establishing risk-
based standards under Section 112(d)(4).
Capping risk-based emission limits for incinerators, cement kilns,
and lightweight aggregate kilns at an HCl-equivalent emission rate
corresponding to the MACT interim standards would not increase
compliance costs (by definition). Thus, the cap would help ensure that
emissions are protective of public health with an ample margin of
safety, and that there are no significant adverse environmental
impacts.
To implement the cap, you would ensure that the hydrogen chloride
and chlorine gas emission rates you use to calculate the HCl-equivalent
emission rate for incinerators, cement kilns, and lightweight aggregate
kilns would not result in total chlorine emission concentrations
exceeding the standards provided by Sec. Sec. 63.1203, 63.1204, and
63.1205.

E. What Would Your Risk-Based Eligibility Demonstration Contain?

To enable regulatory officials to review and approve the results of
your risk-based demonstration, you would include the following
information, at a minimum: (1) Identification of each hazardous waste
combustor combustion gas emission point (e.g., generally, the flue gas
stack); (2) the maximum capacity at which each combustor will operate,
and the maximum rated capacity for each combustor, using the metric of
stack gas volume emitted per unit of time, as well as any other metric
that is appropriate for the combustor (e.g., million Btu/hr heat input
for boilers; tons of dry raw material feed/hour for cement kilns); (3)
stack parameters for each combustor, including, but not limited to
stack height, stack area, stack gas temperature, and stack gas exit
velocity; (4) plot plan showing all stack emission points, nearby
residences, and property boundary line; (5) identification of any stack
gas control devices used to reduce emissions from each combustor; (6)
identification of the RfC values used to calculate the HCl-equivalent
emissions rate; (7) calculations used to determine the HCl-equivalent
emission rate as prescribed above; (8) for incinerators, cement kilns,
and lightweight aggregate kilns, calculations used to determine that
the HCl-equivalent emission rate limit for each combustor does not
exceed the standards for total chlorine at Sec. Sec. 63.1203, 63.1204,
and 63.1205; and (9) the HCl-equivalent emission rate limit for each
hazardous waste

[[Page 21303]]

combustor that you will certify in the Documentation of Compliance
required under Sec. 63.1211(d) that you will not exceed, and the
limits on the operating parameters specified under Sec. 63.1209(o)
that you will establish in the Documentation of Compliance.
If you use the look-up table analysis to demonstrate that your
facility is eligible for the risk-based alternative for the total
chlorine emission limit, your eligibility demonstration would also
contain, at a minimum, the following: (1) Calculations used to
determine the average stack height of on-site hazardous waste
combustors; (2) identification of the combustor stack with the minimum
distance to the property boundary of the facility; (3) comparison of
the values in the look-up table to your maximum HCl-equivalent emission rate.
If you use a site-specific compliance demonstration to demonstrate
that your facility is eligible for the risk-based alternative for the
total chlorine emission limit, your eligibility demonstration would
also contain, at a minimum, the following: (1) Identification of the
risk assessment methodology used; (2) documentation of the fate and
transport model used; and (3) documentation of the fate and transport
model inputs, including the stack parameters listed above converted to
the dimensions required for the model. In addition, you would include
all of the following that apply: (1) Meteorological data; (2) building,
land use, and terrain data; (3) receptor locations and population data;
and (4) other facility-specific parameters input into the model. Your
demonstration would also include: (1) Documentation of the fate and
transport model outputs; (2) documentation of any exposure assessment
and risk characterization calculations; and (3) documentation of the
predicted Hazard Index for HCl-equivalents and comparison to the limit
of less than or equal to 1.0.

F. When Would You Complete and Submit Your Eligibility Demonstration?

You would be required to submit your eligibility demonstration to
the permitting authority for review and approval.\179\ In addition you
would submit an electronic copy of the demonstration to reag@epa.gov
(preferably) or a hard copy to: U.S. EPA, Risk and Exposure Assessment
Group, Emission Standards Division (C404-01), Attn: Group Leader,
Research Triangle Park, North Carolina 27711.
---------------------------------------------------------------------------

\179\ Since the Title V permitting authority is delegated to
States in virtually all instances, the permit limit would thus be
issued as a matter of State authority (generally in parallel with a
delegation of section 112 authority pursuant to CAA section 112(l)),
and be reviewable only in State courts.
---------------------------------------------------------------------------

Requiring prior approval of these eligibility demonstrations is
warranted because hazardous waste combustor may feed chlorine at high
feedrates which may result in emissions of hydrogen chloride and
chlorine gas that approach or exceed the RfCs (i.e., absent compliance
with either the MACT standards or the section 112(d)(4) risk-based
standards). Thus, prior approval of alternative HCl-equivalent emission
rate limits is warranted to ensure that emissions are protective with
an ample margin of safety.
1. Existing Sources
If you operate an existing source, you must be in compliance with
the emission standards on the compliance date. Consequently, if you
elect to comply with the alternative risk-based emission rate limit for
total chlorine, you must have completed the eligibility demonstration
and received approval from your delegated permitting authority by the
compliance date.
You would submit documentation supporting your eligibility
demonstration not later than 12 months prior to the compliance date.
Your permitting officials will notify you of approval or intent to
disapprove your eligibility demonstration within 6 months after receipt
of the original demonstration, and within 3 months after receipt of any
supplemental information that you submit. A notice of intent to
disapprove your eligibility demonstration will identify incomplete or
inaccurate information or noncompliance with prescribed procedures and
specify how much time you will have to submit additional information.
If your permitting authority has not approved your eligibility
demonstration to comply with a risk-based HCl-equivalent emission
rate(s) by the compliance date, you must comply with the MACT emission
standards for total chlorine gas under Sec. Sec. 63.1216, 63.1217,
63.1219, 63.1220, and 63.1221.\180\
---------------------------------------------------------------------------

\180\ Please note that, if your eligibility demonstration is not
approved prior to the compliance date, a request to extend the
compliance date to enable you to undertake measures to comply with
the MACT standards for total chlorine will not be approved unless
you made a good faith effort to submit a complete, accurate, and
timely eligibility demonstration and to respond to concerns raised
by the permitting authority or U.S. EPA.
---------------------------------------------------------------------------

2. New Sources
If you operate a source that is not an existing source and that
becomes subject to Subpart EEE, you must comply with the MACT emission
standards for total chlorine unless and until your eligibility
demonstration has been approved by the permitting authority.
If you operate a new or reconstructed source that starts up before
the effective date of the emission standards proposed today, or a solid
fuel-fired boiler or liquid fuel-fired boiler that is an area source
that increases its emissions or its potential to emit such that it
becomes a major source of HAP before the effective date of the emission
standards proposed today (and thus becomes subject to emission
standards applicable to major sources, including the standard for total
chlorine), you would be required to comply with the emission standards
under Sec. Sec. 63.1216 and 63.1217 until your eligibility
demonstration is completed, submitted, and approved by your permitting
authority.
If you operate a new or reconstructed source that starts up after
the effective date of the emission standards proposed today, or a solid
fuel-fired boiler or liquid fuel-fired boiler that is an area source
that increases its emissions or its potential to emit such that it
becomes a major source of HAP after the effective date of the emission
standards proposed today (and thus becomes subject to emission
standards applicable to major sources including the standard for total
chlorine), you would be required to comply with the emission standards
under Sec. Sec. 63.1216 and 63.1217 until your eligibility
demonstration is completed, submitted, and approved by your permitting
authority.

G. How Would the Risk-Based HCl-Equivalent Emission Rate Limit Be Implemented?

Upon approval by the permitting authority of your eligibility
demonstration, the HCl-equivalent emission rate limit established in
the demonstration for your hazardous waste combustor(s) becomes the
applicable emission limit for total chlorine in lieu of the MACT
standard for total chlorine.
1. What Are the Testing and Monitoring Requirements?
To ensure compliance with the alternative HCl-equivalent emission
rate limit for your combustor(s), you would conduct performance testing
as required for the MACT standards and establish limits on the same
operating parameters that apply to sources complying with the MACT
standards for total chlorine under Sec. 63.1209(o). You would
establish and comply with these operating parameter limits just as you
would establish and comply with the limits for the MACT emission
standard for total chlorine, with the exception of the

[[Page 21304]]

chlorine feedrate limit, as discussed below. For example, existing
sources would establish these limits in the Documentation of Compliance
required under Sec. 63.1211(c) and begin complying with them not later
than the compliance date. Existing sources would also revise the
operating limits as necessary based on the initial comprehensive
performance test and begin complying with the revised operating limits
not later than when the Notification of Compliance is postmarked, as
required under Sec. Sec. 63.1207(j) and 63.1210(b).
The limit on chlorine feedrate required under Sec. 63.1209(o)(1)
would be established differently to ensure compliance with the HCl-
equivalent emission rate limit rather than the total chlorine emission
standard. To ensure that facility-wide hazardous waste combustor
emissions of HCl-equivalents result in exposures equivalent to a Hazard
Index of less than or equal to 1.0, the feedrate limit for chlorine
would be established as the average of the test run averages and the
averaging period for compliance would be one year. A yearly rolling
average is appropriate for risk-based emission limits rather than the
12-hour rolling average applicable to the MACT standards because the
risk-based emission limit is based on chronic exposure.
As discussed in Section B.2.e above, although we conclude that the
chronic exposure Hazard Index would always be higher and thus be the
basis for the total chlorine emission rate limit, we still must be
concerned about acute exposure attributable to short-term emission
rates higher than the maximum average emission rate limit. For example,
the annual average limit on chlorine (i.e., total chlorine and
chloride) feedrate would allow a source to feed very high levels of
chlorine for short periods of time, potentially resulting in
exceedances of the acute exposure Hazard Index based the AEGL-1 values
for hydrogen chloride and chlorine gas. We specifically request comment
on how a short-term limit on chlorine feedrate could be established for
each hazardous waste combustor to ensure that the acute exposure Hazard
Index is less than or equal to 1.0. One approach would be for you to
extrapolate from the chlorine feedrate during the comprehensive
performance test to the feedrate projected to achieve emission rates of
hydrogen chloride and chlorine gas that result in an acute exposure
Hazard Index of 1.0.\181\ This feedrate would be a 1-hour average
feedrate limit. This approach uses the reasonable assumption that there
is a proportional relationship between chlorine feedrate and the
emission rate of hydrogen chloride and chlorine gas. To extrapolate
feedrates, you would consider the system removal efficiency achieved
during the performance test for sources equipped with wet or dry acid
gas scrubbers and for cement kilns.\182\ Other sources would assume a
zero system removal efficiency because any removal efficiency that may
be measured would be incidental and not reproducible.
---------------------------------------------------------------------------

\181\ We also request comment on whether extrapolation of the
chlorine feedrate should be allowed to 100% of the Hazard Index
limit of 1.0, or whether a more conservative approach of limited
extrapolation to a fraction of the Hazard Index (e.g., 0.8) would be
warranted, given the uncertainties inherent in projecting emissions
from extrapolated feedrates.
\182\ We request comment on whether the system removal
efficiency a cement kiln demonstrates during a performance test
because of the alkalinity of the raw material is reasonably
indicative of the system removal efficiency it routinely achieves
(i.e., is the system removal efficiency reasonably reproducible).
---------------------------------------------------------------------------

The approach discussed above would be applicable if you use the
site-specific compliance eligibility demonstration. If you use the
look-up table for your eligibility demonstration, an alternative
approach would be needed to establish a short-term chlorine feedrate
limit. One approach would be to establish a look-up table for maximum
1-hour average HCl-equivalents based on acute exposure. Acute exposure
HCl-equivalents would be calculated using the AEGL-1 values for
hydrogen chloride and chlorine gas, and the look-up table of acute
exposure maximum emission rate limits would be based on normalized air
concentrations for maximum 1-hour average ground level
concentrations.\183\ You would extrapolate the chlorine feedrate from
the level achieved during the comprehensive performance test to a level
that would not exceed the acute exposure HCl-equivalent emission rate
limit for each combustor provided in the look-up table. This feedrate
would be a 1-hour average feedrate limit.
---------------------------------------------------------------------------

\183\ We would use the normalized maximum 1-hour average
concentrations in U.S. EPA, ``A Tiered Modeling Approach for
Assessing the Risk Due to Sources of Hazardous Air Pollutants,''
March 1992, Table 2.
---------------------------------------------------------------------------

We specifically request comment on these approaches to establish a
short-term limit on the feedrate of total chlorine and chloride to
ensure that the acute exposure Hazard Index for hydrogen chloride and
chlorine gas is less than or equal to 1.0.
2. What Test Methods Would You Use?
Although you would comply with the MACT standard for total chlorine
using stack Method 26/26A, certain sources would not be allowed to use
that method to demonstrate compliance with the risk-based HCl-
equivalent emission rate limit.\184\ Cement kilns and sources equipped
with a dry acid gas scrubber should use EPA Method 320/321 or ASTM D
6735-01 to measure hydrogen chloride, and the back-half (caustic
impingers) of Method 26/26A to measure chlorine gas. Incinerators,
boilers, and lightweight aggregate kilns should use EPA Method 320/321
or ASTM D 6735-01 to measure hydrogen chloride, and Method 26/26A to
measure total chlorine, and calculate chlorine gas by difference if:
(1) the bromine/chlorine ratio in feedstreams is greater than 5
percent; or (2) the sulfur/chlorine ratio in feedstreams is greater
than 50 percent.
---------------------------------------------------------------------------

\184\ Even though Method 26/26A may bias total chlorine emission
measurements low for cement kilns for reasons discussed in the text,
it is appropriate to allow compliance with the technology-based MACT
emission standards for total chlorine using that method. Because the
MACT standards are developed using data obtained using Method 26/
26A, allowing that method for compliance will achieve reductions in
total chlorine emissions. For the same reason, it would be
inappropriate to require compliance with unbiased methods because
the average of the best performing sources might not be able to
achieve the standard.
---------------------------------------------------------------------------

a. Method 26/26A Has a Low Bias for Hydrogen Chloride in Certain
Situations. Method 26/26A has a low bias for hydrogen chloride for
sources that emit particulate matter than can adsorb hydrogen chloride:
cement kilns and sources equipped with a dry acid gas scrubber.
Particulate matter caught by the Method 26/26A filter scrubs hydrogen
chloride from the sample gas, and can result in measurements that are
biased low by 2 to 30 times.\185\ Chlorine gas is not adsorbed so that
chlorine gas emissions are not biased by this mechanism.
---------------------------------------------------------------------------

\185\ USEPA, ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume III: Selection of MACT Standards and
Technologies,'' March 2004.
---------------------------------------------------------------------------

b. Method 26/26A Can Have a Low Bias for Chlorine Gas and a High
Bias for Hydrogen Chloride, but Has No Bias for Total Chlorine. Method
26/26A also has a low bias for chlorine and a high bias for hydrogen
chloride when bromine is present at significant levels. Bromine has a
strong effect on the bias. Although the various interhalogen reactions
are extremely complex and may depend on a variety of system parameters,
it appears that each bromine molecule can react with a chlorine
molecule in the acidic impingers of Method 26/26A where hydrogen
chloride is captured, converting the chlorine to chloride ions which are

[[Page 21305]]

reported as hydrogen chloride. Total chlorine measurements (i.e.,
hydrogen chloride and chlorine gas, combined, reported as Cl-
equivalents), however, are not affected. To minimize this bias, we
propose to require sources that have a bromine/chlorine feedrate
exceeding 5 percent to use alternative methods discussed below. Given
the strong bias that bromine can have on M26/26A measurements, we
believe a 5 percent limit on the ratio is within the range of
reasonable values that we could select. We specifically request comment
on this or other approaches to minimize the bromine bias.
Method 26/26A also has a low bias for chlorine and a high bias for
hydrogen chloride when sulfur is present at substantial levels relative
to the levels of chlorine. The capture of chlorine in the acidic
impingers that collect hydrogen chloride has been shown to rapidly
increase when the ratio of SO2/HCl (both expressed in ppmv) exceeds
0.5. Again, total chlorine measurements are not biased. To minimize
this bias, we believe that a 50 percent limit on the ratio of the
sulfur/chlorine feedrate is within the range of reasonable values that
we could select. We specifically request comment on this or other
approaches to minimize the sulfur dioxide bias.
c. Unbiased Methods Are Available. The Agency recently developed
three methods for hydrogen chloride in the context of the Portland
Cement MACT rule for purposes of area source determinations: Methods
320, 321, and 322. Although M322 (GFCIR, Gas Filter Correlation Infra-
Red) is easier to use and less expensive than M320/M321 (FTIR, Fourier
Transform Infra-Red), the Agency did not promulgated M322 in the final
Portland Cement MACT rule because of accuracy concerns resulting from
emissions sampling of lime manufacturing kilns in the context of
developing the Lime Manufacturing MACT rule.
The Agency has also adopted an American Society of Testing and
Materials (ASTM) standard for measuring hydrogen chloride emissions:
ASTM D 6735-01. This method (and M321) is allowed for area source
determinations under the Lime Manufacturing MACT rule. 69 FR 394 (Jan.
5, 2004). The method is an impinger method, like M26/26A, but with
several improvements. For example, the method uses a rejection probe
(i.e., the probe is directed counter to the gas flow), the filter is
heated to minimize adsorption of hydrogen chloride on particulate
matter that may catch on the filter, glassware must be conditioned, and
improved quality assurance/quality control procedures are prescribed.

H. How Would You Ensure That Your Facility Remains Eligible for the
Risk-Based Emission Limit?

1. Changes Over Which You Have Control
Changes in design, operation, or maintenance of a hazardous waste
combustor that may affect the rate of emissions of HCl-equivalents from
the combustor are subject to the requirements of Sec. 63.1206(b)(5).
If you change the information documented in the demonstration of
eligibility for the HCl-equivalent emission rate limit which is used to
establish the HCl-equivalent emission rate limit, you would be subject
to the following procedures.
a. Changes that Would Decrease the Allowable HCl-Equivalent
Emission Rate Limit. If you plan to make a change that would decrease
the allowable HCl-equivalent emission rate limit documented in your
eligibility demonstration, you would comply with Sec.
63.1206(b)(5)(i)(A-C) regarding notifying the permitting authority of
the change, submitting a comprehensive performance test schedule and
test plan, comprehensive performance testing, and restriction on
burning hazardous waste prior to submitting a revised Notification of
Compliance. An example of a change that would decrease the allowable
HCl-equivalent emission rate limit is location of the property boundary
closer to the nearest hazardous waste combustor stack when using the
look-up table to make the eligibility demonstration.
b. Changes that Would Not Decrease the Allowable HCl-Equivalent
Emission Rate Limit. If you determine that a change would not decrease
the allowable HCl-equivalent emission rate limit documented in your
eligibility demonstration, you would document the change in the
operating record upon making such change. If the change would increase
your allowable HCl-equivalent emission rate limit and you elect to
establish a higher HCl-equivalent limit, you must submit a revised
eligibility demonstration for review and approval. Upon approval of the
revised eligibility demonstration, you must comply with Sec.
63.1206(b)(5)(i)(A)(2), (B), and (C) regarding submitting a
comprehensive performance test schedule and test plan, comprehensive
performance testing, and restriction on burning hazardous waste prior
to submitting a revised Notification of Compliance.
2. Changes Over Which You Do Not Have Control
Over time, factors and information over which you do not have
control and which you use to make your eligibility demonstration may
change. For example, if you use a site-specific compliance
demonstration, individuals may locate within the area impacted by
emissions such that the most exposed individual may be exposed to
higher ground level concentrations than previously estimated. This
could lower your allowable HCl-equivalent emission rate limit.
Consequently, you would be required to review the documentation you use
in your eligibility demonstration every five years on the anniversary
of the comprehensive performance test and submit for review with the
test plan either a certification that the information used in your
eligibility demonstration has not changed in a manner that would
decrease the allowable HCl-equivalent emission rate limit, or a revised
eligibility demonstration for a revised HCl-equivalent emission rate limit.
If you determine that you cannot demonstrate compliance with a
lower allowable HCl-equivalent emission rate limit during the
(subsequent) comprehensive performance test because you cannot complete
changes to the design or operation of the source prior to the test, you
may request that the permitting authority grant you additional time as
necessary to make those changes, not to exceed three years.

I. Request for Comment on an Alternative Approach: Risk-Based National
Emission Standards

As noted earlier, another approach to implement section 112(d)(4)--
and one EPA has used in past MACT rules--would be to establish national
emission standards for each source category to ensure that the
emissions from each source within the category are protective of public
health with an ample margin of safety (and do not pose adverse
environmental impacts). Under this approach, dispersion modeling of
representative worst-case sources (or all sources) within a category
would be used to identify an emission level that meets the section
112(d)(4) criteria for all sources within the category. Thus, the same
risk-based national emission standard would be established for each
source in each source category under this approach, rather than the
approach we discuss above of establishing a national exposure standard
based on a uniform level of protection that you would use to establish
a site-specific emission limit.

[[Page 21306]]

The approach of establishing a risk-based national emission
standard for a source category has the advantage of being less
burdensome to implement both for the regulated community and regulatory
authorities. It has the disadvantage, however, of requiring
documentation ``up front'' to support the proposed emission standards.
EPA does not have the time, data, or resources to conduct the analyses
required to support this approach.
The Cement Kiln Recycling Coalition (CKRC), however, has submitted
documentation supporting a national risk-based emission standard for
total chlorine for cement kilns.\186\ CKRC uses normalized air
concentrations from ISC-PRIME and ISCST3 to estimate maximum annual
average and maximum 1-hour average off-site ground level concentrations
of hydrogen chloride and chlorine gas for each source. CKRC assumes
that each kiln emits total chlorine at 130 ppmv, the current Interim
Standard, and that emissions of hydrogen chloride and chlorine gas
partition at the same ratio as measured during the most recent
compliance test. The analysis indicates that the facility Hazard Index
for 1-hour exposures was below 0.2 for the kilns at all facilities, and
the facility Hazard Index for long-term exposures was below 0.2 for the
kilns at 8 of 14 facilities. Emissions from kilns at the remaining 6
facilities can potentially result in facility Hazard Index values up to 0.7.
---------------------------------------------------------------------------

\186\ Trinity Consultants, ``Analysis of HCl/Cl2 Emissions from
Cement Kilns for 112(d)(4) Consideration in the HWC MACT Replacement
Standards,'' September 17, 2003.
---------------------------------------------------------------------------

Notwithstanding that CKRC followed the guidance we suggested to
identify a section 112(d)(4) risk-based emission standard for a source
category, we conclude that establishing a stack gas concentration-based
total chlorine standard of 130 ppmv may not be protective with an ample
margin of safety. Even though the highest Hazard Index for any facility
in the category is below the maximum HI of less than 1.0, the Hazard
Index value for a facility could increase even though sources do not
exceed an emission standard of 130 ppmv. This is because the Hazard
Index is affected by the mass emission rate (e.g., lb/hr) of hydrogen
chloride and chlorine gas individually. Thus the Hazard Index could
increase from the values CKRC has calculated even though each source
complies with a 130 ppmv total chlorine emission standard given that:
(1) The RfC for chlorine gas is 100 times lower than the RfC for
hydrogen chloride; (2) the partitioning of total chlorine between
hydrogen chloride and chlorine gas could change so that a greater
portion is emitted as chlorine; and (3) the mass emission rate of
hydrogen chloride and chlorine gas would increase if the stack gas
flowrate increases.
Because of these concerns, the more appropriate metric for a risk-
based standard for total chlorine would be the toxicity-weighted HCl-
equivalent emission rate discussed above in Section C.1.
To achieve our dual objective of establishing a protective risk-
based emission standard expressed as a toxicity-weighted HCl-equivalent
emission rate (lb/hr) and ensuring that the standard does not allow
total chlorine emission concentrations (ppmv) higher than the current
interim standard of 130 ppmv, we propose that an HCl-equivalent
emission rate limit be established that is achievable by all cement
facilities. This would be an HCl-equivalent emission rate for which on-
site cement kiln emissions of hydrogen chloride and chlorine gas do not
exceed a Hazard Index of 1.0. To make this determination, facilities
would assume that emissions of hydrogen chloride and chlorine gas
partition at the same ratio as measured during the most recent
compliance test. Finally, the HCl-equivalent emission rate limit would
be capped, if necessary, at a limit that ensures that total chlorine
concentrations for each kiln do not exceed 130 ppmv.
If this information and supporting documentation is provided to us,
we would promulgate a toxicity-weighted HCl-equivalent emission rate
that would be applicable to cement kilns.
On a related matter, we evaluated whether using hydrogen chloride
and chlorine gas emissions data obtained with stack sampling Method 26/
26A to project hydrogen chloride and chlorine gas emissions in CKRC's
analysis compromised the results. Method 26/26A is known to
underestimate hydrogen chloride emissions from cement kilns.\187\ We
discuss above in Section F.2 concerns about Method 26/26A and the
rationale for proposing to require sources to use methods other than
Method 26/26A to measure emissions of hydrogen chloride and chlorine
gas for compliance with risk-based standards. Briefly, Method 26/26A
results for hydrogen chloride are biased low for cement kilns, although
results for chlorine gas are unaffected. Even though CKRC used Method
26A results to apportion the 130 ppmv total chlorine assumed emissions
between hydrogen chloride and chlorine gas for each source, the
calculated Hazard Index values are not compromised. Given that the
hydrogen chloride emission levels are biased low, the chlorine gas/
hydrogen chloride ratio that CKRC used to apportion the 130 ppmv total
chlorine emissions between chlorine gas and hydrogen chloride emissions
for each source is biased high. Thus, CKRC projected chlorine gas
emissions that are biased high and hydrogen chloride emissions that are
biased low. These biases result in calculating conservative (i.e.,
higher than actual) Hazard Index values because the health threshold
values are lower for chlorine gas than for hydrogen chloride.\188\
Thus, actual Hazard Index values at an emission level of 130 ppmv total
chlorine would be lower than those that CKRC calculated.
---------------------------------------------------------------------------

\187\ See 63 FR at 14196 (March 24, 1998).
\188\ For the same reasons, HCl-equivalent emission rates that
CKRC may use in an eligibility demonstration for the source category
would be biased conservatively high.
---------------------------------------------------------------------------

XIV. How Did EPA Determine Testing and Monitoring Requirements for the
Proposed Rule?

The CAA requires us to develop regulations that include monitoring
and testing requirements. CAA section 114 (a) (3). The purpose of these
requirements is to allow us to determine whether an affected source is
operating in compliance with the rule.
We propose testing and monitoring requirements for solid fuel-fired
boilers, liquid fuel-fired boilers and hydrochloric acid production
furnaces that are identical to those applicable to incinerators, cement
kilns, and lightweight aggregate kilns under Sec. Sec. 63.1207,
63.1208, and 63.1209.\189\ Please note, however, that we discuss below
a proposed requirement for boilers that would not be subject to a
numerical dioxin/furan emission standard to conduct a one-time test for
dioxin/furan emissions. In addition, in Part Three of today's preamble,
we request comment on, or propose revisions to, several compliance
requirements. Any amendments to the compliance requirements that we
promulgate would be applicable to all hazardous waste combustors. In
addition, we discuss below in this

[[Page 21307]]

section proposed compliance procedures for emission standards that
would be based on normal rather than compliance test data and that
would be applicable to all hazardous waste combustors subject to such a
standard. Finally, we discuss below in this section proposed compliance
procedures for emission standards based on hazardous waste thermal
emissions that would be applicable to all hazardous waste combustors.
---------------------------------------------------------------------------

\189\ Please note that we also propose to revise the existing
schedule for the initial comprehensive performance test for
incinerators, cement kilns, and lightweight aggregate kilns. Under
the proposed revised schedule, owners and operators of incinerators,
cement kilns, and lightweight aggregate kilns would be required to
conduct the initial comprehensive performance test to document
compliance with the replacement standards proposed today (Sec. Sec.
63.1219, 63.1220, and 63.1221) within 12 months of the compliance
date. See discussion in Part Three, Section I.F.
---------------------------------------------------------------------------

The rationale for the testing and monitoring requirements, and
implementation of the requirements, is the same as discussed in the
rulemakings promulgating those requirements for hazardous waste-burning
incinerators, cement kilns, and lightweight aggregate kilns, and as
discussed in Part Three of today's preamble. See 61 FR 43501 (August
23, 1996), 62 FR 24212 (May 2, 1997), 67 FR 6791 (February 13, 2002),
and 67 FR 6967 (February 14, 2002). For this reason, we only summarize
those identical requirements and our rationale for them in today's
notice.\190\
---------------------------------------------------------------------------

\190\ For this reason, in the technical support documents for
today's proposed rule we also refer extensively to the technical
support documents for the Phase I rule.
---------------------------------------------------------------------------

A. What Is the Rationale for the Proposed Testing Requirements?

The proposed rule requires solid fuel-fired boilers and liquid
fuel-fired boilers to perform an initial comprehensive performance test
for dioxin/furan,\191\ mercury, particulate matter, semivolatile
metals, low volatile metals, and total chloride to demonstrate
compliance with emission standards. Hydrochloric acid production
furnaces would be required to perform an initial comprehensive
performance test for dioxin/furan and total chloride to demonstrate
compliance with emission standards. All three source categories are
also subject to the destruction and removal efficiency standard.
Compliance with the destruction and removal efficiency standard,
however, is based on a one-time emissions test, and previous
destruction and removal efficiency testing under RCRA requirements may
be used for that demonstration if design, operation, or maintenance of
the source has not changed in a manner that could adversely affect
combustion efficiency and, thus, destruction and removal efficiency.
Finally, all three source categories would be required to demonstrate
compliance with the carbon monoxide/hydrocarbon emission standard
during the comprehensive performance test (and at all other times).
---------------------------------------------------------------------------

\191\ Those boilers that would be subject to a numerical dioxin/
furan standard (i.e., liquid fuel-fired boilers equipped with an
electrostatic precipitator or fabric filter) would be required to
conduct periodic comprehensive and confirmatory testing. Other
boilers would be required to conduct a one-time test for dioxin/
furan emissions under the conditions discussed below in the text.
---------------------------------------------------------------------------

The comprehensive performance test would be conducted every five
years to ensure that the performance of the air pollution control
device has not deteriorated and that other factors that may affect
emissions have not caused an increase in emissions above the standards.
The proposed rule also requires confirmatory testing to ensure
compliance with the dioxin/furan emission standards, the test to be
conducted mid-way between comprehensive performance tests when
operating under typical conditions rather than at performance test
conditions. More frequent confirmatory testing for dioxin/furan is
needed because dioxin/furan emissions can be affected by various and
interrelated factors, some of which are not fully understood, and
because of the particular health hazard posed by emissions of dioxin/furan.
To ensure continuous compliance with the emissions standards, you
would be required to establish limits on key operating parameters
susceptible to continuous monitoring. The limits would be based on
operating values achieved during the comprehensive performance test
when the source successfully demonstrates compliance.\192\ Because
operating limits are calibrated based on operations during the
comprehensive performance test, sources generally operate at the upper
end of the range of normal operations during these tests. These
proposed requirements are discussed below in Section XII.C.
---------------------------------------------------------------------------

\192\ Because the dioxin/furan confirmatory test is conducted
under operating conditions that are within the range of normal
operations rather than at the upper end of the range of normal
operations as during a comprehensive performance test, you would not
reestablish operating conditions for dioxin/furan based on the
confirmatory performance test.
---------------------------------------------------------------------------

B. What Are the Dioxin/Furan Testing Requirements for Boilers That
Would Not Be Subject to a Numerical Dioxin/Furan Emission Standard?

As explained earlier, we are not proposing numerical dioxin/furan
emission standards for solid fuel-fired boilers and for those liquid
fuel-fired boilers that are equipped with wet scrubbers or no
particulate control device. Rather, those boilers would be subject to
the carbon monoxide/hydrocarbon emission standard and the destruction
and removal efficiency standard to help minimize dioxin/furan
emissions. See discussion in Part Two, Sections X.A and XI.A.
We propose that solid fuel-fired boilers and those liquid fuel-
fired boilers that would not be subject to a numerical dioxin/furan
emission standard conduct a one-time dioxin/furan emission test to
quantify the effectiveness of today's proposed surrogate dioxin/furan
emission controls. This test would be performed no later than the
initial comprehensive performance test required under the proposed
standards. The results of this one-time test would be reported with the
test results for the first comprehensive performance test. See proposed
Sec. 3.1207(b)(3).
1. What Is the Rationale for Requiring the Test?
We are adopting this provision pursuant to our authority in CAA
section 114 (a)(1)(D), which allows EPA to require ``any person * * *
who is subject to any requirement of this chapter'' (which includes
section 112) on a one-time, periodic or continuous basis, to ``sample
such emissions (in accordance with such procedures or methods, at such
locations, at such intervals, during such periods and in such manner as
the Administrator shall prescribe)''. The purpose of such monitoring is
``developing or assisting in the development of'' standards under
various provisions of the Act, including section 112. In this case,
monitoring will assist in making determinations under both section
112(d)(6) and section 112(f), which could lead to development of
standards under either or both of these provisions.
Section 112(d)(6) of the Act requires us to ``review, and revise as
necessary emission standards promulgated under this section no less
than every eight years.'' We believe testing that results from
compliance with today's proposed standards will, in nearly all cases,
establish an adequate database for us to perform this review. However,
we would not have sufficient dioxin/furan emissions data for those
boilers that are subject to the carbon monoxide/hydrocarbon standard
and destruction and removal efficiency standard in lieu of a numerical
dioxin/furan standard. We have data from approximately one-third of the
boilers that are not subject to a numerical dioxin/furan standard.
Although those data indicate that these sources emit low concentrations
of dioxin/furan despite the absence of any dioxin/furan control
equipment, we are concerned about extrapolating this performance to the
entire universe of

[[Page 21308]]

the subject boilers because our data set may not be statistically
random and the potential hazard posed by dioxin/furan is high. In fact,
the design of these sources would seem to have the potential for
formation of significant dioxin/furan concentrations.\193\ We think
this proposed testing would add a one-time cost of approximately
$10,000 for each source for which dioxin/furan test data are not
already available, and the cost appears reasonable to enable us to meet
our section 112(d)(6) and 112(f) mandates. Section 112(d)(6) requires
EPA, at specified times, to determine if further technology-based
emission reductions are warranted. Quantified dioxin/furan emission
information from these sources will assist in this determination.
Section 112(f) requires EPA (among other things) to determine if
emissions from all sources subject to section 112(d) standards must be
further reduced in order to assure an ample margin of safety to protect
public health. Having actual emission data from these sources obviously
will assist in making the required section 112(f) determinations for
these sources.
---------------------------------------------------------------------------

\193\ Incinerators equipped with waste heat recovery boilers are
known to emit high levels of dioxin/furan, and hydrochloric acid
production furnaces with waste heat recovery boilers can also emit
high levels of dioxin/furan. Because the mechanisms that affect
formation and control of dioxin/furan are complex and not fully
understood, we are concerned that some of the factors that cause
high dioxin/furan emissions from incinerators and hydrochloric acid
production furnaces equipped with waste heat recovery boilers may
also affect dioxin/furan emissions from boilers.
---------------------------------------------------------------------------

2. What Are the Operating Requirements for the Test?
You must perform the dioxin/furan test under feed and operating
conditions that are most likely to maximize dioxin/furan emissions,
similar to a dioxin/furan comprehensive performance test. Based on
currently available research, the following factors should be
considered for the testing: (1) Dioxin/furan testing should be
conducted at the point in the maintenance cycle for the boiler when the
boiler tubes are more fouled and soot-laden, and not after maintenance
involving soot or ash removal from the tubes; (2) dioxin/furan testing
should be performed following (or during) a period of feeding normal or
greater quantities of metals; (3) dioxin/furan testing should be
performed while feeding normal or greater quantities of chlorine; (4)
the flue gas temperature in some portion of the heat recovery section
of the boiler should be within the dioxin formation temperature window
of 750 to 400[deg]F during the testing; (5) the testing should not be
conducted under optimal combustion conditions; (6) for units equipped
with wet air pollution control systems, the testing should be conducted
after a high solids loading has developed in the scrubber system; and
(7) for solid fuel-fired boilers, the sulfur content of the coal should
be equivalent to or lower than normal coal sulfur levels, and the gas
temperature at the inlet to the electrostatic precipitator or fabric
filter should be close to the operating limit. In addition, unless
sulfur compounds are routinely fed to the unit, dioxin/furan testing
should not be performed after a period of firing high sulfur fuel or
injection of sulfur additives.
The majority of these recommendations are based on research
demonstrating that soot deposits can enhance dioxin/furan formation in
the presence of chlorine and catalytic metal contaminants, with
formation continuing even after cessation of those contaminant feeds to
the system.^{194, 195} The boiler tube deposits serve as a sink
and source for dioxin/furan reactants (catalytic metals and chlorine),
and combined soot-copper deposits have been shown to cause more dioxin/
furan formation than a deposit of soot or copper alone. From analysis
of soot deposits taken from different sections of a firetube boiler,
the highest measured dioxin/furan concentrations were found in those
deposits containing the highest concentrations of copper and chloride.
Those same deposits were removed from the boiler passages where flue
gas temperatures ranged from 600-300[deg]C, which is within the often-
cited optimal temperature region for dioxin/furan formation. Tube
deposits have also been shown to have a negative effect on dioxin
emissions when those deposits have been affected by sulfur dioxide,
which is why dioxin/furan testing is not recommended following a period
of feeding higher-than-normal levels of sulfur to the boiler.
---------------------------------------------------------------------------

\194\ Lee, C.W.; Kilgroe, J.D.; Raghunathan, K. Environ. Eng.
Sci. 1998, 15(1), 71-84.
\195\ Gullett, B.K.; Touati, A.; Lee, C.W. Environ. Sci.
Technol. 2000, 34, 2069-2074.
---------------------------------------------------------------------------

The recommendation not to test under optimal combustion conditions
has been explained previously in the September 1999 Final Rule preamble
discussion. See 64 FR at 52937. Good combustion practices minimize
dioxin/furan emissions by: (1) Destroying trace dioxins/furans that may
be present in feed streams; (2) minimizing gas-phase formation of
dioxins/furans; and (3) minimizing dioxin/furan precursors that may
enhance post-combustion formation.
For units equipped with wet air pollution control systems, it is
also recommended that testing be conducted after a high solids loading
has developed in the scrubber system. Research conducted to explore the
phenomenon of increased dioxin/furan flue gas concentrations across
some wet scrubber systems has shown differing flue gas outlet dioxin/
furan homologue profiles than flue gas inlet profiles to the scrubber,
but similar flue gas outlet homologue profiles to scrubber suspended
solids and sludge profiles.\196\ This result suggests that some type of
memory effect may be associated with suspended solids in a scrubber
system which can cause higher dioxin/furans emissions.
---------------------------------------------------------------------------

\196\ Takaoka, M.; Liao, P.; Takeda, N.; Fujiwara, T.; Oshita,
K. Chemosphere 2003, 53, 153-161.
---------------------------------------------------------------------------

You may use data-in-lieu of testing to document dioxin/furan
emissions for similar on-site boilers. In addition, dioxin/furan
emission data from previous testing would be acceptable, provided the
test was performed in a manner likely to maximize dioxin/furan emissions.

C. What Are the Proposed Test Methods?

The proposed emission standards are method-based standards, meaning
that the stack test methods used for compliance must be the same as
those used to generate the emissions data we used to calculate the
standards. Because alternative stack methods may report lower
emissions, it is appropriate to require use of the same methods for
compliance as sources used to generate the emissions data in our data base.
For this reason, you would be required to use the following stack
test methods for compliance: (1) Method 29 for mercury, semivolatile
metals, and low volatile metals; and (2) Method 26/26A for total
chlorine.\197\ For dioxin/furan, the rule would require use of Method
0023A unless you receive approval to use Method 23. We discuss the
rationale for allowing site-specific approvals to use Method 23 in Part
Three, Section II.D of today's preamble. In addition, for particulate
matter, you would be required to use either Method 5, the method used
to generate the data in our data base or Method 5i. We allow use of
Method 5i because it is more

[[Page 21309]]

precise than Method 5 at lower particulate matter loadings.
---------------------------------------------------------------------------

\197\ Please note that we discuss in Section XIII of the
preamble above concerns with the accuracy of M26/26A for measuring
emissions of total chlorine for cement kilns. As we explain there,
although M26/26A is appropriate for demonstrating compliance with
the MACT standards for cement kilns, it is not acceptable for
demonstrating compliance with risk-based standards developed under
authority of section 112(d)(4) of the Act.
---------------------------------------------------------------------------

These test methods are codified in 40 CFR part 60, appendix A.\198\
---------------------------------------------------------------------------

\198\ Method 0023A, however, is included in ``Test Methods for
Evaluating Solid Waste, Physical/Chemical Methods,'' EPA Publication
SW-846 Third Edition (November 1986), as amended.
---------------------------------------------------------------------------

D. What Is the Rationale for the Proposed Continuous Monitoring Requirements?

The most direct means of ensuring compliance with emissions limits
is the use of continuous emission monitoring systems (CEMS). We
consider other options when CEMS are not available or when we consider
the impacts of including such requirements unreasonable. When
monitoring options other than CEMS are considered, it is often
necessary for us to balance more reasonable costs against the quality
or accuracy of the emissions monitoring data. Although monitoring
operating parameters cannot provide a direct measurement of emissions,
it is often a suitable substitute for CEMS. The information provided
can be used to ensure that air pollution control equipment is operating
properly. Because most parameter requirements are calibrated during
comprehensive performance testing,\199\ they provide a reasonable
surrogate for direct monitoring of emissions. This information
reasonably assures the public that the reductions envisioned by the
proposed rule are being achieved.
---------------------------------------------------------------------------

\199\ Except that some parameters are limited based on the
recommendations/specifications of the manufacturer of the control device.
---------------------------------------------------------------------------

1. What CEMS Requirements Did EPA Consider?
To comply with the carbon monoxide or hydrocarbon emission limits,
you would be required to use a carbon monoxide or hydrocarbon CEMS as
well as an oxygen CEMS to correct the carbon monoxide or hydrocarbon
values to 7% oxygen. See Sec. 63.1209(a). Because boilers and
hydrochloric acid production furnaces are currently required to use
these CEMS to comply with existing RCRA emission standards for carbon
monoxide or hydrocarbons, there would be a minimal incremental
compliance cost.\200\
---------------------------------------------------------------------------

\200\ If you elect to comply with the carbon monoxide standard
rather than the hydrocarbon standard, you would be required to
document that hydrocarbon emissions during the comprehensive
performance test meet the standard.
---------------------------------------------------------------------------

We also evaluated the cost of applying hydrogen chloride CEMS to
boilers and hydrochloric acid production furnaces. We estimate the
capital costs for hydrogen chloride CEMS to be $88,000 per unit and
annualized costs to be $33,000 per unit. We determined these costs
would be unreasonably high considering: (1) The CEMS detects hydrogen
chloride but not chlorine gas, so that compliance with the total
chlorine emission standard could not be monitored; (2) the
effectiveness of operating parameter limits to ensure compliance with
the emission standard for total chlorine; and (3) the relatively low
level of hazard posed by emissions of total chlorine.
Finally, we conclude that the use of CEMS to document compliance
with particulate matter or metal HAP emission standards has not been
demonstrated on hazardous waste combustors in the United States.
2. What Operating Parameter Limits Would Be Required?
To ensure continuous compliance with the proposed emission limits,
you would be required to establish limits on key operating parameters
and continuously monitor the parameters including: feedrate of metals,
chlorine, and, for some source categories, ash; key combustor operating
parameters; and key operating parameters of the control device. See
Sec. 63.1209(j-o). You would also be required to document monitoring
by recordkeeping and reporting. We selected the following requirements
based on reasonable cost, ease of execution, and usefulness of the
resulting data to both owners and operators and EPA for ensuring
continuous compliance with the emission limits.
To ensure continuous compliance with the dioxin/furan emission
limit, you would be required to establish: (1) A limit on maximum gas
temperature at the inlet to a dry particulate matter control device;
(2) a limit on minimum combustion chamber temperature; (3) a limit on
maximum flue gas flowrate or production rate; (4) a limit on maximum
waste feedrate; (5) if your combustor is equipped with an activated
carbon injection system: limits on the particulate matter control
device, as discussed below; a limit on minimum carbon injection rate; a
limit on minimum carrier fluid flowrate or pressure drop; and you must
specify and use the brand (i.e., manufacturer) and type of carbon used
during the comprehensive performance test, unless you document key
parameters that affect adsorption and establish limits on those
parameters based on the carbon used in the comprehensive performance
test; (6) if your combustor is equipped with a carbon bed: you must
monitor the bed life to ensure that it has not reached the end of its
useful life to minimize dioxin/furan (and mercury) emissions at least
to the levels required by the emission standards; you must replace the
bed or bed segment before it has reached the end of its useful life;
you must specify and use the brand (i.e., manufacturer) and type of
carbon used during the comprehensive performance test, unless you
document key parameters that affect adsorption and establish limits on
those parameters based on the carbon used in the comprehensive
performance test; and you must establish a limit on maximum gas
temperature either at the bed inlet or outlet; (7) if your combustor is
equipped with a catalytic oxidizer: limits on minimum and maximum gas
temperature at the inlet to the catalyst; you must replace the oxidizer
when it has reached the maximum service time specified by the
manufacturer; and when replacing the catalyst, the new catalyst must be
equivalent to or better than the one used during the previous
comprehensive performance test as measured by catalytic metal loading
for each metal, space time, and substrate construction; (8) if you feed
a dioxin/furan inhibitor into the combustion system: a limit on minimum
inhibitor feedrate; and you must specify and use the brand (i.e.,
manufacturer) and type of inhibitor used during the comprehensive
performance test, unless you document key parameters that affect the
effectiveness of the inhibitor and establish limits on those parameters
based on the inhibitor used in the comprehensive performance test. See
Sec. 63.1209(k).
To ensure continuous compliance with the mercury emission limit,
owners and operators of boilers would be required to establish: (1) A
limit on the total feedrate of mercury in all feedstreams for solid
fuel-fired boilers, and a limit on mercury in hazardous waste
feedstreams per million Btu of hazardous waste fired for liquid-fuel-
fired boilers; \201,\ \202\ (2) if your boiler is equipped with a wet
scrubber, limits prescribed for control of total chlorine with a wet
scrubber, except for a limit on minimum pH of the scrubber water; (3)
if your boiler is equipped with an activated carbon injection system,
limits on the particulate matter control device as discussed below, and
limits on the activated carbon injection system as

[[Page 21310]]

discussed above for dioxin/furan; and (4) if your boiler is equipped
with an activated carbon bed, limits on the carbon bed as discussed
above for dioxin/furan.
---------------------------------------------------------------------------

\201\ This is because the mercury emission standard for liquid
fuel-fired boilers is a hazardous waste thermal emission
concentration. Liquid fuel-fired boilers would also be required to
monitor the heating value of hazardous waste feeds to ensure
compliance with the hazardous waste thermal emission concentration.
\202\ The mercury feedrate limit would be based on levels fed
during the comprehensive performance test unless the regulatory
authority approves a request for you to extrapolate to a higher
allowable feedrate (and emission rate) limit.
---------------------------------------------------------------------------

You may comply with mercury feedrate limits only, however, if you
elect to assume that all mercury in the feed is emitted. For solid
fuel-fired boilers, you would assume that all mercury in all
feedstreams is emitted under this alternative approach. You would also
establish a limit on minimum flue gas flowrate to ensure compliance
with the mercury emission standard. For liquid fuel-fired boilers where
the mercury emission standard is expressed as hazardous waste thermal
emissions, you would assume that all mercury in all hazardous waste
feedstreams is emitted. You would have to comply with a hazardous waste
thermal feed concentration that would be expressed as the mass of
mercury in the hazardous waste per million Btu heat input contributed
by the hazardous waste. Also, please note that these compliance
requirements would not apply to hydrochloric acid production furnaces
because (as explained earlier) we propose to use the total chlorine
standard as a surrogate for the mercury, particulate matter,
semivolatile metal, and low volatile metal standards for these sources.
See Sec. 63.1209(l).
To ensure continuous compliance with the particulate matter
emission limit, you would be required to establish: (1) Limits on the
control device operating parameters; (2) a limit on maximum flue gas
flowrate or production rate; and a limit on maximum ash feedrate. If
your boiler is equipped with a wet scrubber, you would establish limits
on: (1) For high energy scrubbers only, minimum pressure drop across
the scrubber and either minimum liquid to gas ratio or minimum scrubber
water flowrate and maximum flue gas flowrate; and (2) for all
scrubbers, the solids content of the scrubber liquid or a minimum
blowdown rate. If your boiler is equipped with an electrostatic
precipitator, ionizing wet scrubber, or fabric filter, please note that
we discuss in Part Three, Section II.I. below proposed compliance
parameters for these control devices. Briefly, if your boiler is
equipped with a fabric filter, you must comply with bag leak detection
system requirements. If your boiler is equipped with an electrostatic
precipitator or ionizing wet scrubber, you must either: (1) Install and
operate a particulate matter loading detector as a process monitor to
indicate when you must take corrective measures; or (2) establish
limits on key operating parameters, on a site-specific basis, that are
representative and reliable indicators that the control device is
operating within the same range of conditions as during the
comprehensive performance test, and link those operating limits to the
automatic waste feed cutoff system. Please note that the particulate
matter compliance requirements would not apply to hydrochloric acid
production furnaces, as discussed above. See Sec. 63.1209(m).
To ensure continuous compliance with the semivolatile and low
volatile metal emission limits, you would be required to establish: (1)
A limit on the maximum inlet temperature to the primary dry particulate
matter control device; (2) a limit on maximum feedrate of semivolatile
and low volatile metals from all feedstreams for solid fuel-fired
boilers, and a limit on semivolatile metals and low volatile metals in
hazardous waste feedstreams per million Btu of hazardous waste fired
for liquid-fuel-fired boilers; ^{203, 204} (3) limits (or
process monitors) on the particulate matter control device as discussed
above; (4) a limit on maximum feedrate of total chlorine or chloride in
all feedstreams; and (5) a limit on maximum flue gas flowrate or
production rate. You may comply with semivolatile and low volatile
metal feedrate limits only, however, if you elect to assume that all
semivolatile and low volatile metals in the feed is emitted. For solid
fuel-fired boilers, you would assume that all semivolatile and low
volatile metals in all feedstreams are emitted under this alternative
approach. You would also establish a limit on minimum flue gas flowrate
to ensure compliance with the semi- and low volatile metals emission
standard. For liquid fuel-fired boilers where the semivolatile and low
volatile metals emission standards are expressed as hazardous waste
thermal emissions, you would assume that all semivolatile and low
volatile metals in all hazardous waste feedstreams are emitted. You
would have to comply with a hazardous waste thermal feed concentration
that would be expressed as the mass of semivolatile (or low volatile)
metals in the hazardous waste per million Btu heat input contributed by
the hazardous waste. Also, please note that the semivolatile metal and
low volatile metal compliance requirements would not apply to
hydrochloric acid production furnaces, as discussed above. See Sec.
63.1209(n).
---------------------------------------------------------------------------

\203\ This is because the semivolatile metal and low volatile
metal emission standards for liquid fuel-fired boilers are hazardous
waste thermal emission concentrations. You would also be required to
monitor the heating value of hazardous waste feedstreams to ensure
compliance with the hazardous waste thermal emission concentration.
\204\ The semivolatile and low volatile metal feedrate limits
would be based on levels fed during the comprehensive performance
test unless the regulatory authority approves a request for you to
extrapolate to higher allowable feedrate (and emission rate) limits.
Please note that the semivolatile and low volatile metal feed limits
for liquid fuel-fired boilers are hazardous waste thermal
concentration limits (pounds of metal per million Btu), not mass
feedrate limits, given that the emission standards are expressed as
hazardous waste thermal emissions.
---------------------------------------------------------------------------

To ensure continuous compliance with the total chlorine emission
limit, you would be required to establish: (1) A limit on maximum
feedrate of total chlorine and chloride from all feedstreams for solid
fuel-fired boilers, and a limit on total chlorine and chloride in
hazardous waste feedstreams per million Btu of hazardous waste fired
for liquid-fuel-fired boilers;\205\ (2) a limit on maximum flue gas
flowrate or production rate; (3) if your combustor is equipped with a
high or low energy wet scrubber: a limit on minimum pH of the scrubber
water; a limit on either the minimum liquid to gas ratio or the minimum
scrubber water flowrate and maximum flue gas flowrate; (4) if your
combustor is equipped with a high energy wet scrubber, a limit on
minimum pressure drop across the scrubber; (5) if your combustor is
equipped with a low energy wet scrubber: a limit on minimum pressure
drop across the scrubber; and a limit on minimum liquid feed pressure
to the scrubber; and (6) if your combustor is equipped with a dry
scrubber: a limit on minimum sorbent feedrate; a limit on minimum
carrier fluid flowrate or nozzle pressure drop; and you must specify
and use the brand (i.e., manufacturer) and type of sorbent used during
the comprehensive performance test, unless you document key parameters
that affect the effectiveness of the sorbent and establish limits on
those parameters based on the sorbent used in the comprehensive
performance test. If your combustor is equipped with an ionizing wet
scrubber, please note that we discuss in Part Three, Section II.I.
below proposed compliance parameters for this control device. Briefly,
if your combustor is equipped with an ionizing wet scrubber, you must
either: (1) Install and operate a particulate matter loading detector
as a process monitor to indicate when you must take corrective
measures; or (2)

[[Page 21311]]

establish limits on key operating parameters, on a site-specific basis,
that are representative and reliable indicators that the control device
is operating within the same range of conditions as during the
comprehensive performance test, and link those operating limits to the
automatic waste feed cutoff system.
---------------------------------------------------------------------------

\205\ This is because the total chlorine emission standard for
liquid fuel-fired boilers is a hazardous waste thermal emission
concentration. You would also be required to monitor the heating
value of hazardous waste feedstreams to ensure compliance with the
hazardous waste thermal emission standard.
---------------------------------------------------------------------------

You may comply with a total chlorine and chloride feedrate limit
only, however, if you elect to assume that all chlorine in the feed is
emitted. For solid fuel-fired boilers, you would assume that all
chlorine in all feedstreams is emitted under this alternative approach.
You would also establish a limit on minimum flue gas flowrate to ensure
compliance with the total chlorine standard. For liquid fuel-fired
boilers where the total chlorine emission standard is expressed as
hazardous waste thermal emissions, you would assume that all chlorine
in all hazardous waste feedstreams is emitted. You would have to comply
with a hazardous waste thermal feed concentration that would be
expressed as the mass of chlorine in the hazardous waste per million
Btu heat input contributed by the hazardous waste. See Sec. 63.1209(o).
To ensure continuous compliance with the destruction and removal
efficiency standard, you would be required to: (1) Establish a limit on
minimum combustion chamber temperature; (2) establish a limit on
maximum flue gas flowrate or production rate; (3) establish a limit on
maximum hazardous waste feedrate; and (4) specify operating parameters
and limits to ensure that good operation of each hazardous waste firing
system is maintained. See Sec. 63.1209(j).

E. What Are the Averaging Periods for the Operating Parameter Limits,
and How Are Performance Test Data Averaged To Calculate the Limits?

Except as discussed in Section XIV.F below, we propose that owners
and operators of solid fuel-fired boilers, liquid fuel-fired boilers,
and hydrochloric acid production furnaces establish averaging periods
for the operating parameter limits and calculate the limits from
comprehensive performance test data under the same approaches required
currently for incinerators, cement kilns, and lightweight aggregate
kilns. A detailed discussion of how those approaches work, and the
rationale for them, are provided at 64 FR at 52919-22 (September 30,
1999). That discussion is summarized below.
We propose the following averaging periods: (1) No averaging period
(i.e., instantaneous monitoring) for maximum combustion chamber
pressure to control combustion system leaks; \206\ (2) 12-hour rolling
averages for maximum feedrate of mercury, semivolatile metals, low
volatile metals, total chlorine and chloride, and ash; and (3) one-hour
rolling averages for all other operating parameters. We propose a 12-
hour rolling average for metal, total chlorine and chloride, and ash
feedrate limits to correspond to the potential duration of three runs
of a comprehensive performance test, considering that feedrate and
emissions, are, for the most part, linearly related. We propose an
hourly rolling average limit for all parameters that are based on
operating data from the comprehensive performance test, except
combustion chamber pressure and metal, chlorine, and ash feedrate
limits. Hourly rolling averages are appropriate for these parameters
rather than averaging periods based on the duration of the performance
test because we are concerned that there may be a nonlinear
relationship between operating parameter levels and emission levels of
HAP or HAP surrogates.
---------------------------------------------------------------------------

\206\ Please note, however, that we request comment on the
appropriateness of these combustion system leak requirements in Part
Three of today's preamble.
---------------------------------------------------------------------------

We propose two approaches to calculate limits for operating
parameters: (1) Calculate the limit as the average of the maximum (or
minimum, as specified) rolling averages for each run of the test; or
(2) calculate the limit as the average of the test run averages for
each run of the test. Hourly rolling averages for two parameters--
combustion gas flowrate or production rate and hazardous waste
feedrate--would be based on the average of the maximum hourly rolling
averages for each run. Hourly rolling average and 12-hour rolling
average limits for all other parameters, however, would be based on the
average level occurring during the comprehensive performance test. We
conclude that this more conservative approach is appropriate for these
parameters because they can have a greater effect on emissions, and
because it is consistent with how manual emissions results are
determined.\207\ We also conclude that limits based on the average
level occurring during the comprehensive performance are readily
achievable. This is because sources generally conduct performance
testing at the extreme upper end of the range of normal operations to
provide the operating flexibility needed after establishing operating
parameter limits. Because sources can readily control (during the
performance test and thereafter) the parameters for which limits are
established, the operating limits based on the average of the
performance test runs should be readily achievable under routine operations.
---------------------------------------------------------------------------

\207\ Manual method emission test results for each run represent
average emissions over the entire run.
---------------------------------------------------------------------------

F. How Would Sources Comply With Emissions Standards Based on Normal
Emissions?

Several proposed emission standards would be based on emissions
that are within the normal range of operations for the source rather
than on compliance test emissions that represent the extreme upper end
of the range of normal emissions: \208\ mercury standards for cement
kilns, lightweight aggregate kilns, and liquid fuel-fired boilers, and
semivolatile metal emissions for liquid fuel-fired boilers. To ensure
compliance with emission standards based on normal emissions data, you
would document during the comprehensive performance test a system
removal efficiency for the metals and back-calculate from the emission
standard a maximum metal feedrate limit that must not be exceeded on an
annual rolling average. If your source is not equipped with an emission
control system (such as activated carbon to control mercury) for the
metals in question, however, you must assume zero system removal
efficiency. This is because a source that is not equipped with an
emission control system may be able to document a positive system
removal efficiency, but it is not likely to be reproducible. It is
likely to be an artifact of the calculation of emissions and feeds
rather than a removal efficiency that is reliable and reproducible.
---------------------------------------------------------------------------

\208\ Compliance test emissions represent the upper range of
emissions from a source because operating parameter limits for the
HAP or HAP surrogate are established based on this compliance test.
---------------------------------------------------------------------------

To ensure that you can calculate a valid, reproducible system
removal efficiency for sources equipped with a control system that
effectively controls the metal in question, you may need to spike
metals in the feed during the comprehensive performance test at levels
that may result in emissions that are higher than the standard. This
would be acceptable because compliance with an emission standard
derived from normal emissions data is based on compliance with an
annual average feedrate limit calculated as prescribed here, rather
than compliance with the emission standard during the comprehensive
performance test.
We propose a one-year averaging period for the metal feedrate limit

[[Page 21312]]

because the emission standard represents normal, average emissions.
Although the averaging period could be substantially shorter or longer,
a one-year averaging period is within the range of reasonable averaging
periods and would be readily achievable for a standard based on normal
emissions. The annual rolling average metal feedrate would be updated
each hour based on the average of the 60 previous 1-minute averages.
We propose to retain the hourly rolling average requirement for the
other operating parameter limits, however, for the reasons discussed
above (i.e., to be conservative given the nonlinear relationship
between the operating parameter and emissions, and because the limits
would be readily achievable).

G. How Would Sources Comply With Emission Standards Expressed as
Hazardous Waste Thermal Emissions?

Several proposed emission standards would be expressed as hazardous
waste thermal emissions: mass of pollutant emissions attributable to
the hazardous waste feed per million Btu of hazardous waste fed to the
combustor.
To demonstrate compliance with a hazardous waste thermal emissions-
based standard during a comprehensive performance test, you would
calculate the hazardous waste thermal emissions by apportioning mass
emissions of mercury, semivolatile metals, low volatile metals, or
total chlorine according to the ratio of the mass feedrate of mercury,
semivolatile metals, low volatile metals, or total chlorine and
chloride from hazardous waste feedstreams to the feedrate for all
feedstreams and dividing by the heat input rate (i.e., million Btu/hr)
attributable to the hazardous waste.
To ensure continuous compliance with the hazardous waste thermal
emissions-based standard, you would calculate an operating limit based
on the hazardous waste thermal feed concentration during the
performance test.\209\ The hazardous waste thermal feed concentration
limit would be calculated as the mass feedrate (lb/hr) of mercury,
semivolatile metals, low volatile metals, or total chlorine and
chloride from hazardous waste feedstreams divided by the heat input
rate (million Btu/hr) from hazardous waste feedstreams. For compliance,
you would continuously monitor the feedrate of hazardous waste on a 12-
hour rolling average updated each minute or, for standards based on
normal emissions, on an annual rolling average updated each hour. You
must know the concentration of mercury, semivolatile metals, low
volatile metals, or total chlorine and chloride in the hazardous waste
at all times, and the heating value of the hazardous waste at all
times. Using this information, you would calculate and record the
hazardous waste thermal feed concentration on a 12-hour rolling
average, or for standards based on normal emissions, on an annual
rolling average updated each hour.
---------------------------------------------------------------------------

\209\ If the hazardous waste thermal emission standard is
derived from normal rather than compliance test emissions data,
however, the hazardous waste thermal feed concentration would be
calculated as discussed above in Section F of the preamble.
---------------------------------------------------------------------------

H. What Happens if My Thermal Emissions Standard Limits Emissions to
Below the Detection Limit of the Stack Test Methods?

Under today's proposed thermal emissions standards, the standard
may limit emissions to levels that are below the analytical detection
limit of the stack test method. For example, this may occur with the
semi-volatile metals standard for liquid fuel boilers when allowable
emission levels are below the analytical detection capabilities of
Method 29 when the hazardous waste firing rate or heating value is low.
To address this issue, we are requesting comment on an approach that
would allow you to be in compliance with today's proposed thermal
emission standards if certain sampling and analytical criteria are met.
The first criterion would ensure that the test crew accumulates
enough of the analyte (e.g., metal HAP) in the sample train to ensure
that it is measurable by the laboratory. For example, the amount of HAP
accumulated in a one hour sample may not be sufficient for the
laboratory to quantify. On the other hand, a three hour test would be
more likely to accumulate enough sample, since three times the amount
of that HAP would be collected. Most Method 29 results that comprise
our emissions database are from two to three hour samples. The first
criterion would be met if the facility samples the flue gas for at
least three hours for each run.
The second criterion would ensure that the laboratory uses adequate
quality assurance procedures to measure the HAP in the sample. Section
13.2 of Method 29 provides the analytical detection limits for the
various laboratory methods used to determine the amount of HAP
accumulated in the sample. The second criterion would be met if the
laboratory reports analytical detection limits that are less than or
equal to those reported in section 13.2.
The final criterion is that no HAP represented by the standard can
be present above the analytical detection limit. For the semi-volatile
metals standard, this means that neither lead nor cadmium could be
present above the analytical detection limits for any run of the test.
You would assume that the HAP is present at the full detection limit,
if lead or cadmium are present above the analytical detection limit
during any run of the test.
If you wish to use this provision to demonstrate compliance with
the standard, you would be required to show that all three criteria
have been met in the Notification of Compliance sent to the appropriate
permitting agency. You would not be required to provide advance notice
or obtain prior approval from the permitting authority.

I. Are We Concerned About Possible Negative Biases Associated With
Making Hydrogen Chloride Measurements in High Moisture Conditions?

Several industry stakeholders have brought several scientific
papers to our attention that indicate that Method 26A, used for
compliance with the hydrogen chloride and chlorine gas standards, may
have a significant low bias at wet stacks with low hydrogen chloride
concentrations. These stakeholders have asked us not to establish
standards for hydrogen chloride and chlorine standard below 20 ppmv to
address this substantial negative bias.
We agree that there was a concern early in the development and
deployment of Method 26A that water droplets would not evaporate in the
sampling train and would therefore dissolve hydrogen chloride in the
sample train, before the hydrogen chloride can be caught by the
impingers. EPA determined that this potential problem can be precluded
by providing enough heat to the sample train to evaporate all water
droplets that might collect in the sample probe or filter. Once the
water is evaporated, the hydrogen chloride reenters the sample gas
stream and is collected by the impingers.
EPA's Office of Research and Development (ORD) performed laboratory
studies to document and fully understand this problem. We also
monitored the application of Method 26A and it's SW-846 equivalent to
determine how these concerns may impact hydrogen chloride measurements
made on wet stacks. Our conclusion is that the situations encountered
in ORD's laboratory studies are not encountered when making stack test
measurements.
The Coalition for Responsible Waste Incineration, CRWI, provided a
paper authored by Joette Steger, et al., which

[[Page 21313]]

illustrates this point. (See memorandum to docket for today's proposed
rule from H. Scott Rauenzahn, U.S. EPA, entitled ``Method 26A and
CRWI's Concerns,'' dated March 25, 2004.) Steger found that Method 26A
has a significant negative bias when 40 to 50 percent of the water in
the sample is in the form of water droplets. Under similar sample
conditions, with 60 percent of the water in the form of droplets,
Steger found that providing more heat to the sample train corrected the
negative bias concern.
We also checked our hydrogen chloride emissions data for hazardous
waste combustors to see if water droplets could be present in the
sample line. We found that water droplets could be present in three of
our incinerator test conditions: 327C10 at 5 percent water droplets;
808C1 at 12.5 percent water droplets; and 3024C1 at 8 percent water
droplets. None of these stack conditions approach the 40 to 50 percent
water droplets observed to be a problem by Steger. These stack gas
conditions most closely resemble Steger's run B-5, with 10% water
droplets. No negative bias was observed for Steger's run B-5. We
conclude that this negative bias, while conceptually possible, is not
encountered at hazardous waste combustors with wet stacks.
We request comments on our analysis of these trade association's
concerns, and request more data regarding this issue.

J. What Are the Other Proposed Compliance Requirements?

We propose other compliance requirements for solid fuel-fired
boilers, liquid fuel-fired boilers, and hydrochloric acid production
furnaces that are the same as those currently in place at Sec. 63.1206
for incinerators, cement kilns, and lightweight aggregate kilns. The
rationale for the requirements is the same as discussed in previous
rulemakings for incinerators, cement kilns, and lightweight aggregate
kilns, and compliance procedures would be the same as currently
required for those sources.
The other compliance requirements include provisions for: startup,
shutdown, and malfunction plans; operation and maintenance plans
including a requirement for bag leak detector systems for fabric
filters; automatic hazardous waste feed cutoff systems, including a
requirement for exceedance reporting; combustion system leak
requirements; changes in design, operation, or maintenance that could
adversely affect compliance with emission standards; operator training
and certification requirements; and requirements for sources that elect
to comply with the carbon monoxide standard to document one-time that
hydrocarbons also meet the hydrocarbon standard; and provisions
allowing a one-time demonstration of compliance with the destruction
and removal efficiency standard.
Please note that we propose revisions to, or request comment on,
some of these compliance requirements in Part Three of the preamble.
Any revisions to these requirements that we might make in the final
rule would be applicable to all hazardous waste combustors.

XV. How Did EPA Determine Compliance Times for this Proposed Rule?

Section 112 of the CAA specifies the dates by which affected
sources must comply with the emission standards. New or reconstructed
units must be in compliance with the proposed rule immediately upon
startup or [DATE THE FINAL RULE IS PUBLISHED IN THE Federal Register],
whichever is later. A new or reconstructed unit for purposes of
complying with this proposed rule is one that begins construction after
April 20, 2004.\210\
---------------------------------------------------------------------------

\210\ Please note that a new or reconstructed unit for purposes
of complying with the Interim Standards applicable to incinerators,
cement kilns, and lightweight aggregate kilns is a unit that began
operation after September 30, 1999.
---------------------------------------------------------------------------

Existing sources are allowed up to three years to comply with the
final rule. See proposed Sec. 63.1206(a)(1)(ii) and (a)(2). This is
the maximum period allowed by the CAA. We believe that three years for
compliance is necessary to allow adequate time to design, install, and
test control systems that will be retrofitted onto existing units.

XVI. How Did EPA Determine the Required Records and Reports for the
Proposed Rule?

We propose notification, reporting, and recordkeeping requirements
for solid fuel-fired boilers, liquid fuel-fired boilers and
hydrochloric acid production furnaces that are identical to those
already in place at Sec. Sec. 63.1210 and 63.1211 and applicable to
incinerators, cement kilns, and lightweight aggregate kilns. Please
note, however, that we are proposing a new requirement applicable to
all hazardous waste combustors that would require you to submit a
Notification of Intent to Comply and a Compliance Progress Report.

A. Summary of Requirements Currently Applicable to Incinerators, Cement
Kilns, and Lightweight Aggregate Kilns and That Would Be Applicable to
Boilers and Hydrochloric Acid Production Furnaces

Owners and operators of solid fuel-fired boilers, liquid fuel-fired
boilers, and hydrochloric acid production furnaces would be required to
submit the following notifications to the Administrator in addition to
those required by the NESHAP General Provisions, subpart A of 40 CFR
part 63: (1) Notification of changes in design, operation, or
maintenance (Sec. 63.1206(b)(5)(i)); (2) notification of performance
test and continuous monitoring system evaluation, including the
performance test plan and continuous monitoring system performance
evaluation plan (Sec. Sec. 63.1207(e)); and (3) notification of
compliance, including results of performance tests and continuous
monitoring system evaluations (Sec. Sec. 63.1210(b), 63.1207(j);
63.1207(k), and 63.1207(l)). You would also be required to submit
notifications to the Administrator if you request or elect to comply
with various alternative requirements. Those notifications are listed
at Sec. 63.1210(a)(2).
Owners and operators of solid fuel-fired boilers, liquid fuel-fired
boilers, and hydrochloric acid production furnaces would be required to
submit the following reports to the Administrator in addition to those
required by the NESHAP General Provisions, subpart A of 40 CFR part 63:
(1) Startup, shutdown, and malfunction plan (if electing to comply with
Sec. 63.1206(c)(2)(ii)(B)); (2) excessive exceedances report (Sec.
63.1206(c)(3)(vi)); and (3) emergency safety vent opening reports
(Sec. 63.1206(c)(4)(iv)).
Owners and operators of solid fuel-fired boilers, liquid fuel-fired
boilers, and hydrochloric acid production furnaces would be required to
keep records documenting compliance with the requirements of Subpart
EEE. Recordkeeping requirements are prescribed in Sec. 63.1211(b), and
include requirements under the NESHAP General Provisions, subpart A of
40 CFR part 63.

B. Why Is EPA Proposing Notification of Intent to Comply and Compliance
Progress Report Requirements?

1. What Is the Notification of Intent to Comply?
In the June 1998 ``fast track'' rule (63 FR 33782), we required
that sources subject to the Phase I subpart EEE standards complete a
Notification of

[[Page 21314]]

Intent to Comply (NIC) no later than October 2, 2000 and conduct a NIC
public meeting no later than July 31, 2000. The NIC and its associated
public meeting served four primary purposes during the early
implementation and compliance phases of the Phase I subpart EEE
requirements which we believe were of benefit to regulators, sources
and the public alike.
First, the NIC served as a compliance planning tool for Phase I
sources because it required you to develop an outline of the key
activities that needed to be completed in order to meet the subpart EEE
standards by the compliance date. It also required that you include the
estimated dates for each of those key activities. Because the NIC was
required to be completed within the first year of implementing the
Phase I requirements, it also may have had the added and important
benefit of encouraging sources to reduce their HAP emissions early. By
focusing a source's attention on the means by which it would achieve
compliance well before the actual compliance date, the NIC may have
prompted some sources to upgrade their combustion design and operations
earlier, thereby yielding an early reduction in HAP emissions. The NIC
also may have prompted earlier waste minimization efforts for the same
reason.
Second, the NIC also served as a planning tool for regulatory
authorities. Based on the information provided in the NIC, regulators
could determine what activities were likely to occur and when over the
course of the three-year compliance period. For example, they could
estimate how many sources needed to modify their combustion units and
existing RCRA permits prior to performance testing, how many sources
intended to stop burning hazardous waste, and how many sources intended
to apply for the comparable fuels exclusion. Using this information,
regulators could plan how to most efficiently allocate their resources
in response to the forthcoming compliance activities of the sources.
Third, the NIC promoted early public involvement by fostering an
open dialogue between sources and the public regarding compliance
strategies for meeting the Phase I subpart EEE standards. Experience
has shown that members of the public are interested in being kept
adequately informed of and having input into the compliance and
permitting activities of hazardous waste combustion facilities. The NIC
and its associated public meeting provided an opportunity for the
public to share their views, thereby allowing the source to develop a
final compliance strategy that met the goals of both the source and the
surrounding community.
Fourth, the public involvement aspect of the NIC also offset any
public participation opportunities that may have been ``lost'' if
sources chose to take advantage of the RCRA streamlined permit
modification process. Many Phase I sources had to modify their
combustion systems' design and/or operations in order to comply with
the MACT standards. Sources that were already operating under RCRA
combustion permits needed to first modify those permits before
initiating any MACT compliance related changes. Normally, a Class 2 or
3 modification would be necessary to incorporate into a RCRA permit the
types of changes we expected would be necessary for sources complying
with Phase I standards. Given that Class 2 and 3 modifications could
have consumed a year or more of a source's three-year subpart EEE
compliance period, we developed a streamlined permit modification
process solely for the purpose of implementing subpart EEE upgrades.
Under the streamlined process, you could request a Class 1 modification
with prior Agency approval to address and incorporate any necessary
MACT upgrades into your RCRA permit. To be eligible to use the
streamlined permit modification, however, you first must have complied
with the NIC requirements, including those related to public involvement.
2. What Happened to the NIC Provisions?
We promulgated the NIC on June 19, 1998 (63 FR 33782) along with
several other requirements related to the Phase I NESHAP. On May 14,
2001, we removed the NIC and two other provisions from the federal
regulations in response to a court mandate to vacate. See 66 FR 24270.
In Chemical Manufacturers Ass'n v EPA, 217 F. 3d 861 (D.C. Cir. 2000),
the court vacated three provisions of the Phase I rule: the Early
Cessation requirement, the NIC and the Compliance Progress Report.\211\
While the panel majority held that we possessed the legal authority to
impose an Early Cessation requirement, the panel also held that we had
claimed the authority to do so without making a showing of a health and
environmental benefit (such as reduced HAP emissions or less hazardous
waste generated) and that this was an impermissible statutory
interpretation. See 217 F. 3d at 865-67. The panel majority further
held that because it could not determine whether we would have
promulgated the NIC and Progress Report requirements absent the Early
Cessation provision, both the NIC and Progress Report requirements
should be vacated as well. However, the panel did agree to issue a stay
of its mandate for a long enough period of time to allow sources to
submit their NICs so that they would be eligible for the RCRA
streamlined permit modification.
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\211\ Under the Early Cessation provision, we required sources
that did not intend to comply with the Phase I standards to stop
burning hazardous waste within two years of the effective date of
the Phase I rule. Under the Compliance Progress Report provision, we
required sources to report to their regulatory agencies the status
of their progress toward compliance with the standards.
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As discussed above, the NIC was intended to serve as a compliance
planning and communication tool. We did not intend the NIC to serve as
the basis for requiring a source to cease burning hazardous waste.
However, as a planning and communication tool we expected sources that
did not intend to comply with the standards to state this in their NIC
and include a schedule of activities that the source would need to
complete in order to stop burning hazardous waste within the two-year
Early Cessation time frame. We believe that the court recognized this
interpretation as our original intent in their agreement to stay their
issuance of the mandate until after sources had submitted their final
NICs on October 1, 2000. By allowing the Phase I sources to complete
the NIC process, the court provided sources with the opportunity to
effectively plan their compliance strategies and take advantage of the
RCRA streamlined permit modification. It also provided the public with
the opportunity for a level of participation that they may not have had
otherwise.
3. Why Is EPA Proposing To Re-Institute the NIC for Phase I Sources?
As stated above, we believe that the NIC was a valuable planning
and communication tool for sources, regulators, and the public during
the early implementation and compliance stages of the 1999 Phase I
subpart EEE requirements. The NIC also provided an additional benefit
to sources upgrading their combustion systems by compensating for any
``lost'' public participation opportunities when using the RCRA
streamlined permit modification process. As discussed in Part One, I. B
and D, we are proposing in today's notice to supplant the existing
Phase I standards with final Replacement standards. We anticipate that
a significant number of Phase I sources may need to conduct additional
upgrades, or in some cases upgrade for the first time, to comply with
the Replacements standards. See

[[Page 21315]]

Sec. Sec. 63.1219, 63.1220, and 63.1221. Re-instituting the NIC for
these sources could provide the same planning and communication
benefits during the initial Replacement standards compliance period
that it did for the original Phase I standards.
Specifically, we expect that by focusing attention early on the
necessary tasks and strategies for achieving compliance, Phase I
sources will be in a better position to meet the Replacement standards
by the compliance date. Regulators will gain insight from the
information provided in the NIC to effectively allocate their resources
to accommodate future regulatory activities. And, the NIC will provide
the public with the opportunity and mechanism to keep abreast of any
significant changes an existing source might need to make as a result
of the Replacement standards. We do not believe that the same planning
and communication opportunities gained from completing the NIC process
are available from other portions of the air regulatory program. For
example, although the public will be notified of a source's obligation
to comply with the Replacement standards during the reopening or
renewal of the source's title V, this notification, in most cases, will
not occur as early in the three-year subpart EEE compliance period, nor
is it likely to include the specific information regarding the source's
compliance strategy.\212\
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\212\ If a major title V source has a remaining permit term of
three or more years on the date the Replacement standards are
promulgated, the title V permitting authority must complete a
reopening of the source's title V permit to incorporate the
requirements of these standards not later than 18 months after
promulgation. Major sources having remaining permit terms of less
than three years on the date the Replacement standards are
promulgated may wait until permit renewal to incorporate the new
standards. Area sources with title V permits likewise may wait until
permit renewal. Permitting authorities must follow the same public
notice procedures for title V permit reopenings and renewals as is
required for initial permit issuance under title V, including
providing public notice of the action, providing a public comment
period of at least 30 days, and providing an opportunity for a
public hearing. See 40 CFR 70.7 and 71.7.
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In addition, while we believe that there will be fewer Phase I
sources in the position of having RCRA combustion permit conditions
after demonstrating compliance with the Interim standards, for those
that do and wish to use the streamlined permit modification process to
allow any necessary Replacement standards upgrades, a second NIC would
provide the same public participation benefits as did the first
NIC.\213\ 40 CFR 270.42(j) currently allows a source to use the RCRA
streamlined modification process provided that the source first
complied with the NIC requirements that were in place prior to October
11, 2000. Since many sources complied with those NIC requirements in
1999 and 2000, the existing regulatory language would allow those same
sources to further modify their RCRA permits for Replacement standards
upgrades. The regulatory language does not make any distinction
regarding when the upgrades are to take place in relation to when the
NIC requirements were to have been fulfilled. We do not believe that it
is appropriate for a source to rely on previous informational and
public participation activities carried out to comply with the earlier
NIC requirements and emission standards to address upgrades occurring
years later in response to a different set of standards any more than
it would be appropriate to allow the public participation activities of
a previous RCRA modification to suffice for a later modification. By
requiring sources that choose to use the RCRA streamlined permit
modification process for Replacement standards upgrades to first
complete a NIC, including its associated public meeting, that
specifically addresses those Replacement standards upgrades, the
community will be kept better informed of additional changes to the
combustion system and the impact on the RCRA permit.
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\213\ Once a source conducts its CPT and submits an Notification
of compliance documenting compliance with the Subpart EEE standards,
the source may request that its RCRA permit be modified to remove
any duplicative limits or conditions. Only those risk-based
provisions that are more stringent than the MACT requirements as
specified in the Notification of compliance or that address other
emission hazards will remain in the RCRA permit. We expect that many
sources will document compliance with the Phase I Interim standards
between 2003 and 2004 and will request the removal of any
duplicative, less stringent provisions from their RCRA permits
shortly thereafter.
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4. Why Is EPA Proposing To Require the NIC for Phase II Sources?
We believe that the NIC would provide the same benefits with
respect to communication and compliance strategy planning for the Phase
II sources that it has for Phase I sources. In addition, without
completing the NIC process, Phase II sources will not be eligible to
take advantage of the RCRA streamlined permit modification when
upgrading their combustion systems. We are proposing that Phase II
sources comply with the same NIC requirements as their Phase I counterparts.
5. How Will the NIC Process Work?
We are proposing to apply a similar NIC process to that which we
promulgated in the June 19, 1998 ``fast track'' rule (63 FR 33782). The
following is a general description of that process. Within nine months
of the promulgation of the final Phase I Replacement standards and
Phase II standards, you would develop and make publicly available a
draft NIC. The draft NIC would contain general information such as
whether you are a major or an area source and what waste minimization,
emission control techniques, and emission monitoring techniques you
might be considering. At the same time, you would also provide a notice
to the public of at least one informal NIC public meeting. Within ten
months, you would hold this public meeting to discuss the activities
you described in the draft NIC for achieving compliance with the
subpart EEE standards. The meeting provides an opportunity for a mutual
understanding between you and the public regarding compliance options,
including consideration of both technical (e.g., equipment changes to
upgrade air pollution control devices) and operational (e.g., process
changes to minimize waste generation) alternatives. We expect the
exchange between you and the community at the meeting to be similar to
that which would occur at RCRA pre-application meetings. That is, we
intend for the meeting to provide an open, flexible and informal
occasion for you and the public to discuss various aspects of your
compliance strategy, provide an opportunity for sharing ideas and
provide an opportunity for building a framework for a solid and
positive working relationship. Lastly, you would submit a final NIC to
your regulatory authority that would include the information provided
in the draft NIC (revised as necessary after the public meeting) as
well as a summary of the public meeting. This final NIC would be
submitted to your regulatory authority within one year of the
promulgation of the final Phase I Replacement standards and Phase II standards.
In summary, we believe that the NIC would provide important
planning and communication opportunities for both Phase I and Phase II
sources. It also would allow all Phase I, as needed, and Phase II
sources to take advantage of the RCRA streamlined permit modification
procedure. Thus, we are proposing NIC requirements for both Phase I and
Phase II sources.

[[Page 21316]]

6. What Is the Compliance Progress Report?
In addition to the NIC, we also promulgated Compliance Progress
Report requirements in the 1998 ``fast track'' rule. See 63 FR 33782.
The purpose of the Progress Report was to help regulatory agencies
determine if sources were making reasonable headway in their efforts to
come into compliance. The Progress Report was required to be submitted
at the midpoint of the three-year compliance period and contain
information that essentially built on the information you previously
provided in the NIC. For example, if you indicated in the NIC that you
needed to make specific physical modifications to your combustion
system in order to comply with the standards, you would be expected to
describe your progress in making those modifications in your Compliance
Progress Report. Although the Progress Report was primarily intended as
a tool for the regulatory agencies, we believe it also may have been
beneficial to sources as well. For example, the Progress Report could
have been used by sources as a mechanism to review and make any
necessary changes to their original strategy for achieving compliance.
As discussed in the previous section, the Court vacated the early
cessation, NIC and Compliance Progress Report provisions of the Phase I
rule in Chemical Manufacturers Ass'n v EPA, 217 F. 3d 861 (D.C. Cir.
2000). Although the Court's primary focus was the early cessation
provision, it also vacated the Progress Report requirements because it
could not determine whether we would have promulgated those
requirements absent the early cessation provision.
7. Why Is EPA Requesting Comment on Requiring the Compliance Progress
Report for Phase I and Phase II Sources?
We believe that the Progress Report would be a useful tool for both
regulators and sources in measuring progress toward achieving
compliance with the Subpart EEE standards and determining if any
revisions to a source's compliance strategy are necessary. Unlike the
NIC, however, we do not have practical experience with the application
of the Compliance Progress Report, because the Court vacated its
requirements prior to their implementation. As a result, we are
requesting comment on whether or not the Compliance Progress Report
should be required for Phase I or Phase II sources.
8. How Would the Compliance Progress Report Requirement Work?
The Compliance Progress Report requirements would be similar to
those promulgated for Phase I sources in the June 19, 1998 ``fast
track'' rule (63 FR 33782). Within two years of the promulgation of the
final standards, you would develop and submit to your regulatory
authority a Compliance Progress Report. The Report would include
information which demonstrates your progress toward compliance. This
could include, for example, completed engineering designs for any
physical modifications to the combustion unit that are needed to comply
with the standards; copies of construction applications; and binding
contractual commitments to purchase, fabricate, and install any
necessary equipment, devices, and ancillary structures. In addition,
you would be expected to include a detailed schedule that lists the
dates for all remaining key activities and projects that will bring you
into compliance with the standards. For example, you would include bid
and award dates for construction contracts, milestones for
groundbreaking, and dates for the approval of permits and licenses. We
would also expect you to include in your report any updates or changes
to the information you previously provided in your NIC, including if
you have changed your compliance plan based on engineering studies or
evaluations that you have conducted since your NIC submittal.\214\
Sources that intend to cease burning hazardous waste prior to or on the
compliance date would still be expected to submit a report describing
key activities and projected dates for initiating RCRA closure and
discontinuing hazardous waste activities at the combustion unit.
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\214\ For example, if you reported in your NIC that you intended
to upgrade your existing unit, but later determined that it was more
appropriate to replace the unit with a new unit, we would expect you
to inform your regulatory agency of this change in your compliance
plan in your Compliance Progress Report.
---------------------------------------------------------------------------

XVII. What Are the Title V and RCRA Permitting Requirements for Phase I
and Phase II Sources?

In today's notice of proposed rulemaking, we are maintaining the
same general approach we took in the 1999 rule with respect to title V
and RCRA permitting requirements and the Phase I sources. We feel that
this approach, to place the MACT air emissions and related operating
requirements in the title V permit and to continue to require RCRA
permits for all other aspects of the combustion unit and the facility
that are governed by RCRA, is still the most appropriate method to meet
our obligations under both statutes. In 1999, our goal in developing a
permitting scheme to accommodate both statutes with respect to air
emission limitations and standards, was to avoid duplication to the
extent practicable and to streamline requirements. We remain committed
to that goal, as we revise and refine the permitting approach we
finalized in 1999.

A. What Is the General Approach To Permitting Hazardous Waste
Combustion Sources?

In the September 1999 rule, we finalized a permitting approach that
places the MACT air emissions and related operating requirements in the
title V permit and retains all other RCRA related requirements (e.g.,
corrective action, general facility standards, other combustor specific
concerns such as material handling, risk-based emission limits and
operating requirements, and other hazardous waste management units) in
the RCRA permit. See 64 FR 52828, 52833-52834 (September 30, 2000).
Under this approach, sources comply with their RCRA emission limits and
operating requirements until they demonstrate compliance with the MACT
standards by conducting a comprehensive performance test and submitting
a Notification of Compliance (NOC) to the Administrator (or authorized
State) that documents compliance.\215\ Upon documenting compliance
through the NOC, sources may begin the transition from RCRA permitting
to title V permitting.
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\215\ There is no change to our decision to subject Phase I area
sources to the same MACT standards and title V permitting
requirements as the major sources. For Phase II sources, area
sources are required to meet the same MACT standards as major
sources, but only for: dioxin/furan, mercury, carbon monoxide/
hydrocarbons, and destruction and removal efficiency. See Part Two,
Section I.A. for more information on regulation of area sources.
Therefore, Phase II area sources will be required to obtain a title
V permit only for those MACT standards as discussed later in
Paragraph C.4. of this section.
---------------------------------------------------------------------------

We believe that this approach still makes the most sense in terms
of providing flexibility and minimizing duplication between the two
permitting programs, while ensuring that there is no break in
regulatory coverage. It is also appropriate given where sources will be
in the transition process of complying with the MACT Interim Standards
upon promulgation of the Phase I Replacement standards and the Phase II
standards. The majority of Phase I sources will have initiated a

[[Page 21317]]

significant modification of their title V permits to include the
operating requirements of their NOC and a modification of their RCRA
permits to remove duplicative conditions. By this time, permitting
authorities and sources are familiar with the current permitting
approach and have worked through many issues to make compliance with
the Interim Standards and the ensuing transition successful. We feel
that permitting authorities and sources would prefer to draw upon their
experiences and utilize the expertise they have developed, rather than
exploring ways to implement a new permitting scheme. Therefore, we are
retaining the same general approach to permitting for Phase I sources
and are proposing to apply this same general approach to Phase II
sources in today's Notice of proposed rulemaking: to place the MACT
emission standards only in the CAA regulation at 40 CFR part 63 subpart
EEE, and rely on implementation through the air program and operating
permit programs developed under title V.
1. What Is the Authority for the Proposals Discussed in This Section?
EPA is issuing these proposals to modify RCRA permits under the
authority of sections 1006(b), 2002, 3004, 3005 and 7004(b) of RCRA.
With regard to the regulatory framework that would result from today's
proposal, we are proposing to eliminate the existing RCRA stack
emissions national standards for hazardous air pollutants for hazardous
waste combustors. That is, after submittal of the NOC established by
today's rule and, where applicable, RCRA permit modifications at
individual facilities, RCRA national stack emission standards will no
longer apply to these hazardous waste combustors. We originally issued
emission standards under the authority of section 3004(a) and (q) of
RCRA, which calls for EPA to promulgate standards ``as may be necessary
to protect human health and the environment.'' We believe that the
proposed MACT standards are generally protective of human health and
the environment, and that separate RCRA emission standards are not
needed to protect human health and the environment. Refer to Part Four,
Section IX. How Does the Proposed Rule Meet the RCRA Protectiveness
Mandate? for a discussion on this topic.
In addition, RCRA section 1006(b) directs EPA to integrate the
provisions of RCRA for purposes of administration and enforcement and
to avoid duplication, to the maximum extent practicable, with the
appropriate provisions of the Clean Air Act (and other federal
statutes). This integration must be done in a way that is consistent
with the goals and policies of these statutes. Therefore, section
1006(b) provides further authority for EPA to eliminate the existing
RCRA stack emissions standards to avoid duplication with the new MACT
standards.
We are not proposing, however, that RCRA permit conditions to
control emissions from these sources will never be necessary, only that
the national RCRA standards appear to be unnecessary. Under the
authority of RCRA's ``omnibus'' clause section 3005(c)(3); see 40 CFR
270.32(b)(2)), RCRA permit writers may impose additional terms and
conditions on a site-specific basis as may be necessary to protect
human health and the environment. Thus, if MACT standards are not
protective of human health and the environment in an individual
instance, RCRA permit writers will establish permit limits that are
protective.
In RCRA, Congress gave EPA broad authority to provide for public
participation in the RCRA permitting process. Section 7004(b) of RCRA
requires EPA to provide for, encourage, and assist public participation
in the development, revision, implementation, and enforcement of any
regulation, guideline, information, or program under the Act.
2. Is EPA Proposing a Different Permitting Approach for New Sources?
As discussed above, we are maintaining the same general permitting
approach as before. However, we are proposing to eliminate the
unintended result of the previous regulatory construct, which caused
new sources to initially be subject to the RCRA air emission and
operating requirements. In particular, we want to specify that any
hazardous waste burning incinerators, cement kilns, lightweight
aggregate kilns, boilers, and hydrochloric acid production furnaces
newly entering the RCRA permitting process (e.g., sources that are
seeking an initial RCRA permit or permit modification to include a new
hazardous waste combustion unit) after promulgation of the Phase I
Replacement standards and Phase II standards are not subject to certain
specified RCRA permit requirements or performance standards. The
approach we are proposing today is similar to the one we proposed in
the July 3, 2001, proposed amendment rule (see 66 FR 35146), but was
not finalized. The amendment was not finalized due to several
unresolved issues and thus, it was agreed (during litigation settlement
discussions), that we would revisit and address the issues in the Phase
I Replacement standards and Phase II standards rulemaking.
a. Why Is EPA Proposing a Different Permitting Approach for New
Sources? In the September 1999 rule, we had amended language in 40 CFR
264.340, 265.340, 266.100, 270.19, 270.22, 270.62, and 270.66 to
accommodate the permit transition from RCRA to the CAA. To summarize,
the amended language in these sections says that once a source
demonstrates compliance with the standards in 40 CFR part 63 subpart
EEE, the requirements in specified part 264, 265, 266, and part 270
sections would no longer apply. However, the amended language neglected
to specifically address if, how, or when new sources would make the
transition from RCRA permitting requirements to CAA MACT requirements.
As we discussed in the preamble to the July 3, 2001, proposed
amendments, under RCRA, new sources must obtain a permit or a permit
modification before they may start construction of a new source/unit.
The way the current part 270 language reads, new sources subject to the
1999 rule and the Interim Standards rule are not able to demonstrate
compliance with the part 63 standards until after a RCRA permit is
issued, the source is built, and they conduct performance testing. This
means they would have to submit a trial burn plan with their RCRA
permit application and also submit suggested conditions for the various
phases of operation--start-up/shake-down, trial burn, and post-trial
burn. Likewise, RCRA permitted facilities that are adding a new
combustion source would have to provide the same information with their
permit modification request. Whether the source is new or adding a new
combustion source, the permit writer would have to review this
information and write conditions into the RCRA permit governing all
phases of combustor operations. This expenditure of resources, on the
part of the source and the permitting agency, is unnecessary given that
the conditions will become inactive or be removed from the RCRA permit
upon compliance with the MACT standards. For new sources, compliance
with the MACT standards is upon start-up. Therefore, today we are
proposing that new sources (whether a new source or a new source at an
existing permitted source) who will be subject to the Phase I
Replacement standards and Phase II standards upon start-up, not follow
the RCRA permitting process for establishing combustor emissions and

[[Page 21318]]

operating requirements (i.e., submission of a trial burn plan with the
RCRA permit application, submission of suggested conditions for the
various phases of operation--start-up/shake-down, trial burn, and post-
trial burn, and ultimately obtaining a permit with operating and
emission standards).
b. How Is EPA Proposing to Change the Current Requirements for New
Sources? In the July 3, 2001 proposal, we developed regulatory language
to clarify our intent not to require new sources to obtain a RCRA
permit with respect to combustor operations and emissions. In response
to that proposal, we received comments from the Sierra Club expressing
concerns that the increased opportunities for public participation
established in the RCRA Expanded Public Participation Rule (60 FR
63417, December 11, 1995) would be lost. This rule involves communities
earlier in the permitting process, provides more opportunities for
participation, expands public access to information, and offers
guidance on how facilities can improve public participation. In a
follow-up discussion with the Sierra Club, they specifically expressed
interest in being able to influence decisions on the construction of
hazardous waste combustors. Upon consideration, we agree with the
Sierra Club that in our previous effort to streamline the RCRA
permitting process for new sources, we did not fully consider that
important opportunities for public participation may be lost. Although
we still believe that new sources, whether a new source or an existing
source adding a new source, should not be required to follow the RCRA
permitting process, we also believe that the Sierra Club's concerns
have merit. It makes sense to afford the public the same (or as close
as possible) public participation opportunities for new units under the
HWC MACT/CAA framework that they had under the RCRA regulations.
Therefore we are modifying our earlier proposal as discussed in the
paragraphs below, to consider several options that will attempt to
address these concerns, as well as provide a means to improve the
existing regulatory requirements for new sources.
The RCRA Expanded Public Participation Rule implemented four new
requirements for facilities and permitting agencies that enable
communities to become more active participants throughout the
permitting process. They are: (1) Permit applicants must hold an
informal public meeting before applying for a permit; (2) permitting
agencies must announce the submission of a permit application which
will tell community members where they can view the application while
the agency reviews it; (3) permitting agencies may require a facility
to set up an information repository at any point during the permitting
process if warranted; and (4) permitting agencies must notify the
public prior to a trial (or test) burn. Consequently, we will focus on
each of these and propose mechanisms that mirror or fulfill the RCRA
public participation requirements.
We stated earlier in this section that under RCRA, new sources must
obtain a permit (or a permit modification at an existing source) before
they may start construction of a new source. This holds true regardless
of whether we finalize an approach that does not require new sources to
obtain a RCRA permit that contains the combustor operating and
emissions standards (i.e., a RCRA permit will still be required to
address all other activities at the facility including corrective
action, general facility standards, other combustor specific concerns
such as material handling, risk-based emission limits and operating
requirements, and other hazardous waste management units). So, in
applying for a RCRA permit, new hazardous waste facilities/sources will
still be required to meet the public participation requirements.
However, the problem arises if new sources are not required to provide
information relative to the combustor (i.e., sources were formerly, at
this point in the process, required to submit a trial burn plan), but
only for the other proposed hazardous waste management activities at
the source. Thus, the source would not be required to discuss the
proposed combustor-specific operations and emissions at the informal
public meeting, nor would the permit application that is made available
to the public to review, contain information regarding the combustor
operations or emissions.
In an effort to provide an opportunity for public participation
equivalent to RCRA, we believe that the Notification of Intent to
Comply (NIC) requirements, as proposed in Part Two, Section XVI.B.,
serve in place of the first two RCRA public participation requirements.
The primary functions of the NIC are to serve as a compliance planning
tool and to promote early public involvement in the permitting process.
In terms of compliance planning, the draft NIC must contain general
information including the waste minimization, emission control, and
emission monitoring techniques that are being considered and how the
source intends to comply with the emission standards. With regard to
early public involvement, a draft of the NIC must be made available to
the public for review within 9 months of the effective date of the
final Replacement Standards and Phase II Standards rule. One month
later, the source must hold an informal public meeting to discuss the
activities described in the NIC. The NIC requirements apply to new
sources as well (see Sec. 63.1212(b)(1) in today's Notice), but the
timing will vary according to the date a new source begins burning
hazardous waste. For example, if a new source begins burning 3 months
after the rule's effective date, then it will have only 6 months before
it must prepare and make a draft NIC available for public review.\216\
More significantly, according to 40 CFR 63.1212(b)(2), as proposed in
today's Notice, new sources that are to begin burning more than 9
months after the effective date of the final rule will be required to
meet all of the NIC and Compliance progress report requirements in
Sec. Sec. 63.1210(b) and (c), 63.1211(c), and 63.1212(a) prior to
burning hazardous waste.
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\216\ Note that new sources must have prepared and included
their documentation of compliance in the operating record upon
start-up. New sources then have 6 months from the date of start-up
to begin their comprehensive performance test.
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We feel that the NIC requirements are commensurate with the public
participation requirements to hold an informal public meeting to inform
the community of the proposed combustor operations and to make the
compliance information available for public review and comment. On the
other hand, we also recognize that there are a few gaps. For instance,
the NIC requirements are not associated with a permit action and the
regulatory agency is not required to be present at the NIC public
meeting. We would, however, expect the source to consider any comments
raised during the NIC process as it develops its final compliance
strategy and final NIC.\217\ Also, if a new source begins burning after
the effective date of today's rule, but prior to 9 months after the
effective date, the NIC is not required to be made available for public
review before a new source begins burning. In other words, the public
is not provided information relative to the combustor's operations,
emissions, and compliance schedule prior to it beginning operations.
Given these gaps, we are proposing a scenario in which the NIC
requirements for new sources under MACT, could be crafted

[[Page 21319]]

to achieve a comparable level of public participation as under RCRA.
---------------------------------------------------------------------------

\217\ If necessary, concerns raised regarding the regulation of
the combustor can be addressed through application of RCRA's omnibus
provision (RCRA section 3005(c)(3)).
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We are proposing to require that all new sources prepare a draft
NIC and make it available to the public at the same time as their RCRA
pre-application meeting notice. We also propose that new sources submit
their comprehensive performance test plan at this time. By submitting
the NIC and CPT plan together, the public would be provided with
compliance-related information relevant to the combustor as well as the
proposed combustor operations and emissions (i.e., the public is
provided testing information through the CPT that they would have
received via the trial burn plan). Lastly, as part of this option we
propose that the NIC public meeting coincide with the informal public
meeting for the RCRA permit. By holding a simultaneous meeting, the
public is given the opportunity to inquire and comment on both the
source's proposed activities and the combustor's proposed operations
with regulatory officials from both the Air and RCRA programs present.
We request comment on this discussion.\218\
With respect to the information repository regulations at 40 CFR
124.33, the purpose of the information repository is to make
information (i.e., documents, reports, data, and information deemed
necessary) available to the public during the permit issuance process
and during the life of a permit. While the Title V permit procedures
specify that information relevant to the permitting decision be made
available to the public,\219\ this information would not be accessible
prior to construction or operation of the combustor. Under RCRA, the
information repository would be established some time after submission
of the permit application, but before construction and operation of the
combustor. Even though an information repository is not a required
component of the RCRA permit process, the regulations provide a
permitting agency with the discretion to evaluate the need for and
require a source to establish and maintain one. Therefore, so that the
public is afforded the same opportunities to view and copy information
such as the NIC, test plans, draft Title V permit and application,
reports and so forth under MACT, we are considering two options. We
could include a provision similar to Sec. 124.33 in the NIC
regulations for new sources. It would allow a regulatory agency, on a
case-by-case basis, to require a source to establish an information
repository specific to the combustor. We believe the NIC regulations
are a suitable location to place such a provision, since the NIC is the
first opportunity for the public to discuss the combustor operations
and emissions. Alternatively, rather than incorporate provisions for an
information repository in the NIC regulations, the applicability
language in Sec. 124.33 could be amended to include new combustion
sources that will comply with Part 63, subpart EEE upon start-up. We
request comment on this discussion.
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\218\ Since the public participation requirements of 40 CFR
124.31 and 124.32 only apply to initial RCRA permits and renewals
with significant changes, a corresponding regulatory amendment would
need to be made to the applicability paragraphs to include
modifications to RCRA permits only for new combustion sources that
will comply with Part 63, subpart EEE upon start-up. Also,
63.1212(b) would need to be amended to reference Sec. Sec. 124.31
and 124.32.
\219\ 40 CFR Sec. 70.7(h)(2) requires that information
including the draft Title V permit, the application, all relevant
supporting materials, and other materials available to the
permitting authority that are relevant to the permit decision, be
made available to interested persons.
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The last RCRA public participation requirement requires the
permitting agency to notify the public prior to a trial burn or test
burn at a combustion facility. If new sources are not required to
follow the RCRA permitting process with respect to combustor emissions
and operations, they also would not be required to submit a trial burn
plan with their permit application or conduct a trial burn. However,
under MACT, new (and existing) combustion sources are required to
submit performance test and continuous monitoring system (CMS)
performance evaluation test plans for approval. The MACT performance
test serves the same purpose as the RCRA trial burn test: To
demonstrate compliance with the relevant emission standards and to
collect data to determine at what levels the corresponding operating
conditions should be set. Similar, but not identical to the RCRA
requirements at 40 CFR 270.62 and 270.66 requiring the permitting
agency to notify the public prior to a trial/test burn, the MACT
performance test regulations (see Sec. 63.1207(e)(2)), specify that a
source must issue a public notice announcing the approval of the test
plans and provide a location where the public may view them. Although
the timing of the public notices are slightly different, the
regulations both provide notice to the public about testing. Under
RCRA, notice is given to the public prior (usually 30 days) to
commencement of the trial burn, whereas under MACT, notice is given
when the test plans are approved. The newly amended regulations of
Sec. 63.1207(e)(2) proposed in this Notice, specify that sources must
make the test plans available for review at least 60 days prior to
commencement of the test and must provide the expected time period for
commencing (and completing) the test. Thus, the public is informed of
the test and provided estimates of test dates through public notice of
the approved test plan.
Thus far, the approach we have proposed is intended to ensure that
the public will have the same opportunities for participation and
access to information as they would if new sources continued to be
subject to the RCRA permit process to include the combustor emission
and operating requirements. By proposing that new sources not be
required to obtain a RCRA permit with combustor emission and operating
requirements, it provides for the smoothest and most practical
transition from RCRA requirements to MACT requirements.\220\
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\220\ This approach does not eliminate the possibility that some
combustor-specific requirements may be retained in the RCRA permit
such as: Risk-based conditions, compliance with an alternative MACT
standard, compliance with startup, shutdown and malfunction events
under RCRA rather than the CAA, etc. See section XVII, D.2. for a
more complete discussion. Consequently, sources would be expected to
include the applicable RCRA conditions in their RCRA permit application.
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Aside from the approach we have focused on, there are others that
may be worthy of consideration. We can also look at the option of a
transition point for new sources that would specify how far a new
source would proceed down the RCRA permit path before it could
``transition'' over to compliance with the MACT standards and CAA
permitting. There are three additional options we can consider relative
to a transition point: (1) After the RCRA Part B application is
submitted; (2) after the RCRA permit is issued; and (3) after the
source places its Documentation of Compliance (DOC) in the operating record.
Beginning with the first option, each successive one moves in the
direction toward the way new sources currently make the transition from
RCRA to MACT and includes modifications to the RCRA information
requirements. We envision each of these options to be a variation of
the current RCRA permit process. Under the first option, the transition
point would occur after the source submits its RCRA Part B application.
The key to this option is that the source would be subject to the
public participation requirements of 40 CFR 124.31 and 124.32, to hold
an informal public meeting and to have the submission of the permit
application noticed. However, new sources would

[[Page 21320]]

not be required to include the combustor's operation and emission
information in the Part B application. Rather, the source would only be
required to discuss the compliance-related activities related to the
combustor as part of the informal public meeting. For the second
option, the transition point would be after the permitting agency
issues the RCRA permit. The source would not only discuss the
combustor's compliance-related activities as part of the RCRA informal
public meeting as in the first option, but it would also address the
operations and emissions through development of a trial burn plan, or a
CPT plan in lieu of the trial burn plan, or even a coordinated CPT/RCRA
trial burn plan, if it is likely that the source will require some RCRA
permit conditions (i.e., risk-based conditions). With this option, even
though all activities pre-permit issuance must address the source and
the combustor's operations and emissions, the approved permit would not
contain the operating and emission requirements (with the exception of
risk-based or alternative standards). For the third option, the
transition point would be after the source places its DOC in the
operating record, which indicates the source's compliance with the MACT
standards. Basically, the source would proceed down the RCRA permit
path as in option two by complying with the public participation
requirements, submitting a trial burn plan/CPT plan/coordinated plan,
suggesting conditions for the various phases of operation, and
receiving a RCRA permit. However, in this option, the permit would need
to address combustor operations and emissions to the extent that it
would cover the construction and start-up/shakedown periods.
With respect to the public participation requirements, all three
options automatically factor in the first two RCRA public participation
requirements (by virtue of where the transition would be made).
However, we did not discuss how we would account for the remaining two
public participation requirements. We believe that the information
repository and the notification of a trial burn requirements can be
addressed in the same manner as we discussed in our proposed approach.
So, for these options, we would incorporate an appropriate requirement,
either through the NIC regulations or the public participation
regulations, that would allow for an information repository to be
established. Regarding the notice of a trial burn, we believe that the
notice of the performance test is equivalent.
In summary, our proposed approach involves modifying the NIC
provisions to include RCRA public participation requirements. The
second group of options consider a range of transition points that are
also worthy of consideration. We invite comment on this discussion.
3. What Are the Proposed Changes to the RCRA Permitting Requirements
That Will Facilitate the Transition to MACT?
To alleviate potential conflicts between the RCRA permit
requirements and MACT, we are proposing an additional streamlined
permit modification provision, requiring prior Agency approval, which
would allow an existing RCRA permit to be better aligned with specific
provisions contained in the Subpart EEE requirements. The intent of
this provision is to reduce potential burdens associated with
compliance with overlapping RCRA and MACT requirements, while still
maintaining the overall integrity of the RCRA permit.
a. How Will the Overlap During Performance Testing Be Addressed?
When we finalized the performance test requirements and the changes to
the RCRA permitting requirements in the September 30, 1999, rule, we
did not consider how sources would conduct their performance tests
while at the same time, maintain compliance with their RCRA permit
requirements. For instance, during the performance test, a source will
likely want to conduct testing at the edge of the operating envelope or
the worst case for certain parameters to ensure operating flexibility.
This could conflict with established operating and emissions limits
required in the source's RCRA permit and consequently, prevent the
source from optimizing its testing range.
Currently, sources have three options that would allow them to
resolve any potential conflicts between their performance test and
their RCRA permit requirements. One option would be for a source to
submit a RCRA Class 2 or 3 permit modification request to temporarily
change or waive specific RCRA permit requirements during the MACT
performance test (see Sec. 270.42, appendix I, L.5). Another option
would be for a source to request approval for such changes through its
RCRA trial burn plan or coordinated MACT / RCRA test plan (see Sec.
270.42, appendix I, L.7.a. or d.). In this case, a source could include
proposed test conditions in its plan to temporarily waive specific RCRA
permit requirements during the test. The last option would be for a
source to request a temporary authorization that would allow specific
RCRA permit requirements to be waived for a period of 180 days (see
Sec. 270.42(e)).
We do not believe that any of the options discussed above provide
an optimal solution to resolving conflicts between a source's
performance test protocol and its RCRA permit operating and emissions
limits. A Class 2 or 3 RCRA permit modification may not be an option
for many sources due to the time typically involved in processing these
requests. Sources that choose to modify their permits would need to do
so well in advance of conducting their performance test to ensure that
the modification would be processed in time to conduct the test on
schedule. This may result in sources submitting modification requests
prior to approval of their performance test plans. We believe that RCRA
permit writers are unlikely to approve any modifications to RCRA permit
requirements without the assurance that the source will be operating
under an approved test plan. Resolving conflicts using a trial burn or
coordinated test plan is not a viable option for a source that has
already completed its trial burn/risk burn testing. Lastly, while a
temporary authorization is relatively streamlined, it is meant to be
used in unique cases affecting an individual facility. We believe that
it is most logical and easily implemented to propose a modification
that can be used consistently to remedy a common problem affecting an
entire group of facilities with similar operations (e.g., hazardous
waste burning combustors facing barriers to testing due to RCRA permit
requirements). Therefore, in today's Notice, we are proposing to allow
sources to waive specific RCRA permit operating and emissions limits
during pretesting, initial, and subsequent performance testing through
a new streamlined permit modification procedure.\221\
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\221\ For subsequent performance tests, we anticipate that this
modificaiton would be useful for sources that may have risk-based or
alternative requirements in their RCRA permits.
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We believe that a process for waiving specific RCRA permit
requirements during performance testing is consistent with our
objectives to streamline requirements and minimize conflicts between
the RCRA and CAA programs without sacrificing the protections afforded
by RCRA. Moreover, we view this new permit modification to be
complementary to the provisions of Sec. 63.1207(h) for waiving
operating parameter limits (OPLs) during

[[Page 21321]]

performance testing. In the February 14, 2002 final amendments rule, we
reiterated that OPLs in the Documentation of Compliance (DOC) may be
revised at any time to reflect testing parameters for the initial
performance test prior to submission of the NOC and so, in effect, are
automatically waived. Also, we revised the language in Sec.
63.1207(h)(1) and (2) to not require that subsequent performance test
plans be approved in order to waive OPLs, but rather that sources only
record the emission test results of the pretesting.
b. Are There Other Instances Where the New Streamlined Permit
Modification Can Be Used? In addition to our efforts today to minimize
overlapping permit requirements during performance testing, we are also
proposing to allow the new streamlined permit modification to address
other potential conflicts. In implementing the 1999 rule, it has become
clear that there are several other instances when conflicts may arise
where RCRA permit requirements overlap with MACT requirements. For
example, the required averaging period for an operating parameter might
be slightly different between MACT and the RCRA permit, requiring two
different data acquisition schemes during the interim period between
submittal of the Documentation of Compliance (DOC) and the final
modification of the RCRA permit after receipt of the NOC. Or, if a RCRA
permit requires periodic emissions testing, the specified test schedule
in the permit might not be aligned with the required test schedule for
MACT, causing a facility to perform duplicate testing instead of
allowing a single coordinated RCRA/MACT test event. Conflicts in
operating limitations, monitoring and recordkeeping requirements, and
scheduling provisions can be especially prevalent during this interim
period. Consequently, we believe the new streamlined permit
modification procedure would be appropriate to address these probable
overlaps.
c. Why Is a New Streamlined Permit Modification Procedure Being
Proposed? This new streamlined modification differs from the one we
finalized in the June 1998 ``fast track'' rule (63 FR 33782). In 1998,
we provided for a streamlined RCRA permit modification process whereby
you could request a Class 1 modification with prior Agency approval to
address and incorporate any necessary MACT upgrades into your RCRA
permit (see 40 CFR 270.42, appendix I, L(9)). The streamlined permit
modification provision, which was intended solely for the purpose of
implementing physical or operating upgrades, allowed sources that were
already operating under RCRA combustion permits to modify their
combustion systems' design and/or operations in order to comply with
the MACT standards without having to obtain a Class 2 or 3 RCRA permit
modification. Thus, L(9) was not intended to account for overlapping
requirements. Further, to be eligible to use L(9), you first must have
complied with the NIC requirements, including those related to public
involvement. Refer to Part Two, Section XVI for a discussion of the NIC.
However, similar to the streamlined modification we finalized as
L(9), we feel that this new streamlined modification warrants a Class 1
modification with prior Agency approval. We feel that a Class 1 is
appropriate considering that: we do not expect that there would be
significant changes when requesting certain RCRA permit requirements to
be waived; it would be applicable for a relatively short period of
time; regulatory oversight is incorporated via approval of the
modification request and; the intended goal of the modification is to
achieve environmental improvement ultimately through implementation of
more protective standards.
d. How Will the New Streamlined Permit Modification Work? Our
proposed approach allows for a waiver of specific RCRA permit
requirements provided that you: (1) Submit a Class 1 permit
modification request specifying the requested changes to the RCRA
permit, with an accompanying explanation of why the changes are
necessary and how the revised provisions will be sufficiently
protective, and (2) obtain Agency approval prior to implementing the
changes.\222\ When utilized to waive permit requirements during the
performance test, you also must have an approved performance test plan
prior to submitting your modification request. (We believe that the
Class 1 modification with prior Agency approval will ensure that your
proposed test conditions are reasonable with respect to your existing
permit limits (i.e. that they are sufficiently protective); and that an
approved performance test plan confirms that you have met the
regulatory requirements for performance test plans.)
---------------------------------------------------------------------------

\222\ Refer to the new section in the RCRA permit modification
table in 40 CFR 270.42, appendix I, L(10) and new regulatory
language in 270.42(k), that must be used to waive specified permit
requirements.
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We propose that you submit your streamlined modification request in
sufficient time to allow the Director a minimum of 30 days (with the
option to extend the deadline for another 30 days) to review and
approve your request. For purposes of performance testing, we propose
that you submit your request at the time you receive approval of your
performance test plan, which is 90 days in advance of the test and
coincides with the time limitations imposed on the Director for
approval. Additionally, we are requiring that the waiver of permit
limits only be relevant during the actual testing events and during
pretesting for an aggregate period of up to 720 hours of operation. In
other words, it would not apply for the duration of time allotted to
begin and complete the test (i.e., the entire 60 days).
As a side note, we realize that some sources may not have an
approved performance test plan by the date their test is scheduled to
begin because the Administrator failed to approve (or deny) it within
the specified time period, which could render this new streamlined
modification impractical. However, we expect that sources would
petition the Administrator to waive their performance test date for up
to 6 months, with an additional 6 months possible, rather than to
proceed with the performance test without the surety of an approved
test plan.\223\
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\223\ See 40 CFR 63.1207(e)(3) for performance test time
extension requirements.
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B. How Will the Replacement Standards Affect Permitting for Phase I Sources?

1. Where Will Phase I Sources Be in Their Transition to MACT With
Respect to Their RCRA Permits?
We discussed earlier that by the time the Phase I Replacement
standards and Phase II standards are finalized, most Phase I sources
will have completed their initial comprehensive performance test and
submitted their NOC documenting compliance with the MACT Interim
Standards.\224\ This marks the point at which sources will begin to
transition from RCRA permitting requirements to CAA requirements and
title V permitting. For sources with RCRA permits, they must continue
to comply with the operating standards and emission limits in their
permits until any duplicative requirements are either removed through a
permit modification, expire, or are automatically inactivated via a
sunset clause contained in the permit. For sources operating under
interim status,

[[Page 21322]]

they must comply with the RCRA interim status requirements until they
demonstrate and document compliance with the MACT Interim Standards. We
anticipate that sources who are in the process of renewing their RCRA
permits would work with their permit writers to include sunset clauses
to inactivate duplicative requirements upon compliance with the MACT
Interim Standards. Given the permit actions taken during the transition
period leading up to compliance with the Interim Standards, we believe
that many sources will have had duplicative requirements removed from
their permits by the time the Replacement Standards are promulgated.
For sources that have not had their RCRA permits modified, we expect
that they will proceed with a modification to remove duplicative
requirements.\225\
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\224\ Some sources will receive extensions of up to one year to
conduct their initial comprehensive performance test (see 40 CFR
63.1207(e)(3)). Therefore, their transition point will occur at a
later time designated by the extension.
\225\ A streamlined permit modification was developed in the
1999 rule to allow the removal of duplicative conditions from RCRA
permits (see Sec. 270.42, appendix I, section A.8).
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2. Where Will Phase I Sources Be in Their Transition to MACT With
Respect to Their Title V Permits?
With regard to title V permits, Phase I major and area sources were
required to submit a title V permit application 12 months after the
effective date of the 1999 rule--or were required to reopen existing
title V permits with 3 or more years remaining in the permit term, 18
months after the effective date--to include the MACT standards. Sources
with less than 3 years remaining could wait until renewal to
incorporate the 1999 standards.\226\ Upon promulgation of the Interim
Standards on February 13, 2002, major sources were required to reopen
their permits or could wait until renewal to include the revised
standards according to the same time frames mentioned above. Therefore,
we expect that all Phase I sources would have title V permits
containing the MACT Interim Standards and potentially, operating
standards in accordance with their DOC, at the time the Replacement
Standards rule is promulgated. Furthermore, most sources will have
initiated a significant modification to their permits to include the
revised operating requirements of their NOC. Regardless of these
required compliance activities leading up to the promulgation date of
the Replacement Standards rule, Phase I sources will again need to
reopen within 18 months or wait until renewal to incorporate the MACT
Replacement standards.
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\226\ Only major sources are required to reopen their title V
permits when 3 or more years remain in the permit term. Even though
area sources were subject to the same standards and title V permit
requirements, they can wait until renewal regardless of the time
remaining to incorporate new or revised standards. The reopening
provisions of 40 CFR 70.7(f) and 71.7(f) only apply to major sources.
---------------------------------------------------------------------------

3. What Is Different With Respect To Permitting in Today's Notice of
Proposed Rulemaking?
Based upon our decision to utilize the same general permitting
approach as in the 1999 and Interim Standards rules, we expect sources
to follow the same transition scheme as it relates to RCRA permit
requirements and the CAA requirements and title V permitting for the
Replacement Standards rule. One aspect, however, that was not addressed
in those rules was how the permitting of new sources would be affected.
Hence, we discuss approaches in this Notice of Proposed Rulemaking (see
Section A.1. above) that would require them to obtain RCRA permits only
for corrective action, general facility standards, other combustor
specific concerns such as material handling, risk-based emission limits
and operating requirements, and other hazardous waste management units
at the source. Should the approach we are proposing be finalized, there
may not be any operating requirements and emission standards to remove
from their RCRA permits.
We also discussed a new streamline permit modification procedure in
section A.2. ``What Are the Proposed Changes to the RCRA Permitting
Requirements that Will Facilitate the Transition to MACT?''. This new
procedure allows sources to waive specific RCRA permit operating and
emission limits during pretesting, performance testing, and other
instances where there may be conflicts during the interim period
between submission of the Documentation of Compliance and final RCRA
permit modification.
Another important difference is our proposal to codify the
authority for permit writers to evaluate the need for and, where
appropriate, require Site-Specific Risk Assessments (SSRA). We are also
proposing to codify the authority for permit writers to add conditions
to RCRA permits that they determine, based on the results of an SSRA,
are necessary to protect human health and the environment. In doing so,
our intent is to change the regulatory mechanism that is the basis for
SSRAs, while retaining the same SSRA policy from a substantive
standpoint. Under this approach, permitting authorities continue to
have the responsibility to ensure the protectiveness of RCRA permits.
Next, we have proposed to re-institute the NIC (see Part Two,
Section XVI for a discussion of the NIC) for Phase I sources and to
require the NIC for Phase II sources. While the NIC serves as a
compliance planning tool and to promote early public involvement, it is
also a requirement before the streamlined permit modification procedure
in 40 CFR 270.42(j) and 270.42, appendix I, section L.9, can be
utilized to make changes to either the combustor design or operations,
in order to comply with the final Replacement Standards. Thus, sources
who have not yet made the transition from their RCRA permits to title V
permits must comply with the NIC requirements to take advantage of the
streamlined permit modification.
Last, a subtle difference pertaining to the transition scheme stems
from the time span between compliance with the Interim Standards and
the effective date of the Replacement Standards relative to RCRA
permits. Sources who received extensions to the date for commencing
their initial comprehensive performance test, whether a 6 month or 12
month extension, will not be required to submit an NOC until either a
few months before or just after the effective date of the final
Replacement Standards rule. Therefore, these sources would be modifying
their RCRA permits just before or after the effective date of the final
rule. Nevertheless, we anticipate that sources will proceed with
modification of their RCRA permits to remove duplicative requirements.

C. What Permitting Requirements Is EPA Proposing for Phase II Sources?

Phase II sources are presently subject to the RCRA permitting
requirements for hazardous waste combustors provided in 40 CFR 270.22
and 270.66. We are proposing in today's notice to apply the same
approach to permitting Phase II sources that we did for Phase I sources
in the September 1999 rule. Specifically, we propose to:
(1) Place the new Phase II emission standards only in the CAA
regulations at 40 CFR part 63, subpart EEE, and rely on their
implementation through the air program,
(2) Specify that, with few exceptions, the analogous standards in
the RCRA regulations no longer apply once a facility demonstrates
compliance with the MACT standards in subpart EEE, and
(3) Require that the new standards be incorporated into operating
permits issued under title V of the CAA rather than be incorporated
into RCRA permits.
Our goal with regard to permitting Phase II sources remains the
same as the goal that we had for Phase I sources--to accommodate the
requirements of

[[Page 21323]]

both the RCRA and CAA statutes, while at the same time avoiding
duplication between the two programs to the extent practicable. The
permitting approach we developed for Phase I sources in the September
1999 rule enables us to achieve this goal. In that rule, we amended the
applicability of 40 CFR 270.19, 270.22, 270.62, and 270.66 so that once
a source demonstrates compliance with the MACT standards, it is no
longer subject to the full array of RCRA combustion permitting
activities, unless the Director of the permitting agency decides to
apply specific RCRA regulatory provisions, on a case-by-case basis, for
purposes of information collection in accordance with Sec. Sec.
270.10(k) and 270.32(b)(2). We are proposing to make a similar change
to 40 CFR 270.22 and 270.66 for Phase II sources. In addition, we are
proposing for Phase II sources, as we are for Phase I sources, that new
sources not follow the RCRA permitting process for establishing
combustor emissions and operating requirements. Of course, as for Phase
I sources, Phase II sources would remain subject to the RCRA permitting
requirements for all other aspects of their combustion unit and
facility operations, including general facility standards, corrective
action, other combustor-specific concerns such as materials handling,
risk-based emission limits and operating requirements, as appropriate,
and other hazardous waste management units at the site.\227\ Also, some
sources will retain specific RCRA permitting requirements if they
choose to comply with an alternative MACT standard; address startup,
shutdown and malfunction events under RCRA rather than the CAA; or, if
an area source, comply with the RCRA metals, particulate matter, or
chlorine standards and associated requirements. It is also important to
note that if you later decide to add a new combustion unit to your
facility, you must first modify your RCRA permit to include the new
unit. This is because your RCRA permit must reflect all hazardous waste
management units at the facility. Although the emissions from the new
unit will be regulated under the CAA MACT standards, as noted above,
your RCRA permit must address any other related requirements for the
new unit.
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\227\ Even though the RCRA air emission standards for combustors
will no longer apply once compliance is demonstrated with MACT
(except in certain cases), other RCRA air emission standards will
continue to apply to other hazardous waste management units at the
facility. For example, part 264, subpart CC, still applies to air
emissions from tanks, surface impoundments, and containers.
---------------------------------------------------------------------------

1. What Other Permitting Requirements Are We Proposing To Apply To
Phase II Sources?
As part of the Phase I rule, we promulgated additional specific
changes to the RCRA permitting requirements in 40 CFR part 270 to
facilitate implementation of the new standards and permit transition
from RCRA to the CAA. First, we added a streamlined RCRA permit
modification process to allow sources to make changes to either their
combustor design or operations, as necessary, in order to comply with
the Phase I standards. This modification process, a Class 1 with prior
Agency approval, was promulgated in the June 19, 1998 ``Fast Track''
rule and is provided in 40 CFR 270.42(j) and 270.42, appendix I,
section L.9. See 63 FR 33785. Second, we further amended the Sec.
270.42, appendix I permit modification table to add a new line item
that streamlines modification procedures for removing conditions from a
permit that are no longer applicable (e.g., because the standards upon
which they are based are no longer applicable to the source). This new
line item is a Class 1 modification requiring prior Agency approval and
is provided in section A.8 of appendix I.\228\ Third, we added a new
section, 40 CFR 270.235, to the RCRA permitting requirements that
address startup, shutdown, and malfunction events and the integration
of those requirements between the RCRA program and the CAA program.
Fourth, we amended the requirements in 40 CFR 270.72 governing changes
that facilities can make while they are operating under interim
status.\229\ We believe that each of the above changes that we made to
the RCRA permitting regulations for Phase I sources are also
appropriate for Phase II sources and thus, are proposing that these
same features apply to Phase II sources. They will serve to ease
implementation of the new standards and transition combustion sources
from RCRA to the CAA.
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\228\ It is important to note that you only may request the
removal of duplicative combustion limits and conditions from your
RCRA permit. Any risk-based conditions that are more stringent than
the MACT requirements would be retained.
\229\ Section 270.72(b) imposes a limit on the extent of the
changes, stating that they cannot amount to ``reconstruction''
(defined in the regulation as ``when the capital investment in the
changes to the facility exceeds 50 percent of the capital cost of a
comparable entirely new hazardous waste management facility'').
Although we did not expect the individual costs to perform changes
required to comply with the MACT standards to exceed this 50 percent
limit, the limit is cumulative for all changes at an interim status
facility. Thus, conceivably there could be situations where MACT-
related changes would cause a source to exceed the limit. To ensure
that the limit would not be a hindrance to MACT compliance, we added
an exemption to paragraph (b) of that section for changes necessary
to comply with standards under 40 CFR part 63, subpart EEE.
---------------------------------------------------------------------------

We did not amend any title V regulations in 40 CFR parts 70 or 71
for Phase I sources. It was our intent during the Phase I rulemaking,
and continues to be our intent for Phase II, to rely on the existing
air program to implement the new MACT requirements, including their
incorporation into a title V operating permit. Thus, we are proposing
that all current CAA title V requirements governing permit
applications, permit content, permit issuance, renewal, reopenings and
revisions will apply to air emissions from Phase II sources. In
addition, the requirements of other CAA permitting programs, such as
air construction permits, likewise will continue to apply, as
appropriate. We also included provisions in the subpart EEE
requirements that address the relationship between the standards and
title V permits. Specifically, we stated in 40 CFR 63.1206(c)(1)(iv)
and (v) that the operating requirements in the Notification of
Compliance are applicable requirements for purposes of parts 70 and 71,
and that these operating requirements will be incorporated into title V
permits. We are proposing the same approach for the interface between
the Phase II standards and title V permits.
2. What Other Permitting Requirements Are We Proposing in Today's
Notice That Would Also Be Applicable to Phase II Sources?
In today's notice, we are proposing three changes to the general
permitting approach for all sources subject to part 63, subpart EEE,
including Phase II sources. First, we are proposing to allow sources to
waive specific RCRA permit operating and emission limits using a
streamlined permit modification procedure. This would apply for
pretesting, performance testing, and other instances where there may be
conflicts during the interim period between submittal of the DOC and
final RCRA permit modification. Second, we are proposing that new units
not be required to obtain a RCRA permit that includes emission limits
or conditions, with certain exceptions (e.g., more stringent risk-based
limits). Third, we are proposing to codify the authority for permit
writers to evaluate the need for and, where appropriate, require SSRAs.
We are also proposing to codify the authority for permit writers to add
conditions to RCRA permits that they determine, based on the results of
an SSRA, are necessary to protect human health and the environment. We
believe

[[Page 21324]]

that each of the above proposals are appropriate for Phase II as well
as Phase I sources and, therefore, are applying them to all hazardous
waste combustors subject to part 63, subpart EEE. See the discussions
provided in A.1 and A.2 of this section.
3. How Will the Permitting Approach Work for Phase II Sources?
In the preamble to the September 1999 rule, we discussed at length
how to implement the new permitting approach, including aspects such as
when and how to transition sources from RCRA permitting to title V. See
64 FR 52981. We have also provided a fact sheet on permit transition in
our Hazardous Waste Combustion NESHAP Toolkit, which is available at
the following Internet address: http://www.epa.gov/epaoswer/hazwaste/
combust/toolkit/index.htm. The information provided in the above-
mentioned preamble and the fact sheet is appropriate for Phase II as
well as Phase I sources. Below is a summary of this information for
sources that already have RCRA permits and for sources that are
currently operating under RCRA Interim Status. The permitting approach
for new sources is discussed earlier in A.1 of this section.
a. Implementing the New Permitting Approach for Phase II Sources
that Already Have RCRA Permits. If you already have a RCRA permit, you
must continue to comply with the conditions in your permit until either
they expire or your permitting authority modifies your permit to remove
them. You can request a permit modification, using line item A.8
provide in appendix I of Sec. 270.42, to request that your permitting
authority remove any duplicative conditions once you have conducted
your comprehensive performance test and submitted a Notification of
Compliance documenting compliance to your CAA regulatory agency. The
appropriate CAA regulatory agency in most cases will be the state
environmental agency.
When you submit your RCRA permit modification request you should
identify the conditions in your RCRA permit that you believe should be
removed. We recommend that you also attach a copy of your Notification
of Compliance. This information will help the RCRA permit writer
determine whether there are any risk-based conditions that need to
remain in your RCRA permit. For example, any conditions imposed under
RCRA omnibus authority, or similar state authority, based on the
results of a site-specific risk assessment that are more stringent than
the corresponding MACT standard or limitation documented in the
Notification of Compliance would have to remain in the RCRA permit. You
should also inform your RCRA permit writer if you intend to comply with
any specific RCRA requirements in lieu of those provided in part 63,
subpart EEE, such as the RCRA startup, shutdown, and malfunction
requirements. Providing this information to the RCRA permit writer
likely will expedite review of your permit modification request.
We expect that in some situations RCRA permit writers may not
approve a request to remove conditions until they know that their
counterparts in the Air program have reviewed the Notification of
Compliance and verified that the facility has successfully demonstrated
compliance with the MACT standards. This may happen, for example, with
facilities that have historically generated a lot of interest or
concern from the community or that have had previous problems in
maintaining compliance with performance standards. If you have received
confirmation that the regulatory agency has made a Finding of
Compliance based on your Notification of Compliance, we recommend you
include that with your RCRA permit modification request as well. Once
people in the Air program responsible for reviewing the Notification of
Compliance have completed their evaluation of the documentation and
test results, we encourage them to inform their RCRA counterparts. This
courtesy will help RCRA permit writers complete their review of the
RCRA permit modification requests, thereby facilitating the permit
transition.
b. Implementing the New Permitting Approach for Sources that Are
Operating under RCRA Interim Status. If you are currently operating
under RCRA interim status, you must continue to meet RCRA performance
standards governing emissions of hazardous air pollutants in 40 CFR
part 266 until you conduct your comprehensive performance test and
submit your Notification of Compliance documenting compliance with the
MACT standards to the regulatory agency. The RCRA combustion permitting
procedures in 40 CFR part 270 also continue to apply until you
demonstrate compliance.
There is not a ``one size fits all'' answer to how facilities
operating under RCRA interim status should make the transition. RCRA
permit writers, in coordination with facility owners or operators,
should map out the most appropriate route to follow in each case. In
mapping out site-specific approaches to transition, both the regulators
and the facility owners or operators should keep in mind the goal we
mentioned earlier of minimizing the amount of time a facility might be
subject to duplicative requirements under the two programs. Factors
they should take into consideration include, but are not limited to the
following. (1) The status of the facility in the RCRA permitting
process at the time the final MACT rule is promulgated. For example--If
a facility is on the verge of conducting a RCRA trial burn, it should
proceed with the trial burn and continue through the RCRA permitting
process. (2) The facility's anticipated schedule for demonstrating
compliance with the MACT standards. For example--If the facility plans
to come into compliance with the standards early, it may make sense to
transition before completing the RCRA permitting process. (3) The
priorities and schedule of the regulatory agency. For example--A state
agency may have made certain commitments (e.g., to the public or to its
state legislature) regarding their RCRA or CAA programs that might
impact its decisions regarding the transition. (4) The level of
environmental concern at a given site. For example--To make sure that
the facility is being operated in a manner protective of human health
and the environment, the regulatory agency may decide to proceed with
RCRA permitting, including the site-specific risk assessment, rather
than delay the RCRA process to coordinate with testing under MACT.
If after evaluating all the relevant factors a decision is made to
proceed with a RCRA permit in advance of a source's MACT compliance
demonstration, we suggest including language to facilitate the eventual
transition. Regulators can attach ``sunset'' provisions to those
conditions that will no longer apply once a source demonstrates
compliance with the part 63 subpart EEE standards.
In making the transition from one program to the other, testing
under one program should not be unnecessarily delayed in order to
coordinate with testing required under the other. As proposed for Phase
II, sources would be conducting periodic performance testing (every
five years) anyway, just as the Phase I sources are required to do. In
both our Hazardous Waste Minimization and Combustion Strategy and in
the September 1999 Phase I rule, we emphasized the importance of
bringing hazardous waste combustion units under enforceable controls
that have been demonstrated to achieve compliance with performance
standards. Stack testing is essentially

[[Page 21325]]

the way to make this demonstration, whether it is performed under the
RCRA or CAA regulatory schemes, and so should be performed as
expeditiously as possible.
4. How Do We Propose Regulating Phase II Area Sources?
In today's Notice, we are not making a positive area source finding
as we have with the Phase I area sources. However, we are using the
``specific pollutants'' authority in section 112(c)(6) of the CAA to
propose that area sources be subject to MACT standards only for certain
hazardous air pollutants. Thus, area sources will be subject to title V
permitting requirements for those pollutants specified per CAA section
112(c)(6).
Under 40 CFR 63.1(c)(2), area sources subject to MACT standards are
also subject to title V permitting, unless the standards for the source
category specifies that: (1) states will have the option to exclude
area sources from title V permit requirements; or (2) states will have
the option to defer permitting of area sources. We did not allow the
states these options in the September 1999 rule for Phase I sources,
and we are not proposing to offer them for Phase II sources either.
Since the RCRA program does not make a distinction between regulating
major and area sources and would no longer be able to address the
pollutants covered by MACT (because the underlying RCRA standards in 40
CFR parts 264, 265, and 266 would no longer be applicable once the
source demonstrates compliance with subpart EEE), we believe that area
sources should not be exempt from the title V permitting requirements.
It is important that there not be a gap in permitting coverage as we
implement the deferral from regulation under RCRA to regulation under
the CAA. In addition, section 502(a) of the CAA requires that any area
source exemptions from the title V permitting requirements be
predicated on a finding that compliance with the requirements is
impracticable, infeasible, or unnecessarily burdensome. We do not
believe that the title V permitting requirements will be impracticable,
infeasible, or unnecessarily burdensome for Phase II area sources,
because these sources are already complying with RCRA permitting
requirements.
As explained above, we are using the ``specific pollutants''
authority to propose that area sources be subject to MACT standards
only for certain hazardous air pollutants: dioxin/furans, mercury, DRE
and carbon monoxide/hydrocarbons. (See Part Two, Section II.C.) For
particulate matter, chlorine and HAP metals other than mercury, we are
proposing that area sources have the option of complying with the MACT
standards for Phase II major sources or continuing to comply with the
RCRA emission standards and requirements. Those Phase II area sources
that choose to comply with the RCRA standards and requirements will be
subject to title V permits for some of their emissions and RCRA permits
for others. In summary, regardless of whether an area source elects to
comply with all or only the pollutants pursuant to CAA section
112(c)(6), a title V permit will be required.

D. How Would this Proposal Affect the RCRA Site-Specific Risk
Assessment Policy?

1. What Is the Site-Specific Risk Assessment Policy?
In the September 30, 1999 Phase I rule, we articulated a revised
Site-Specific Risk Assessment (SSRA) policy recommendation for
hazardous waste burning incinerators, cement kilns and light-weight
aggregate kilns. Specifically, we recommended that for hazardous waste
combustors subject to the Phase I MACT standards, permitting
authorities should evaluate the need for an SSRA on a case-by-case
basis. We further stated that while SSRAs are not anticipated to be
necessary for every facility, they should be conducted where there is
some reason to believe that operation in accordance with the MACT
standards alone may not be protective of human health and the
environment. If the permitting authority concludes that a risk
assessment is necessary for a particular combustor, the permitting
authority must provide the factual and technical basis for its decision
in the facility's administrative record. Should the SSRA demonstrate
that supplemental requirements are needed to protect human health and
the environment, additional conditions and limitations should be
included in the facility's RCRA permit pursuant to the omnibus
authority. The basis and supporting information for those supplemental
requirements also must be documented in the facility's administrative
record. For hazardous waste combustors not subject to the Phase I
standards, we continued to recommend that SSRAs be conducted as part of
the RCRA permitting process. See 64 FR 52841.\230\
---------------------------------------------------------------------------

\230\ We provided further clarification of the appropriate use
of the SSRA policy and technical guidance in an April 10, 2003
memorandum from Marianne Lamont Horinko, Assistant Administrator for
OSWER, to the EPA Regional Administrators titled Use of the Site-
Specific Risk Assessment Policy and Guidance for Hazardous Waste
Combustion Facilities. This document is available in the docket
(Docket # RCRA-2003-0016) established for today's proposed
action.
---------------------------------------------------------------------------

2. Are SSRAs Likely To Be Necessary After Sources Comply With the Phase
I Replacement Standards and Phase II Standards?
As explained earlier, all Phase I replacement standards must be
equivalent to or more stringent than the negotiated interim standards.
Many of the replacement standards proposed in today's notice would be
more stringent than the interim standards (e.g., 64 [mu]g/dscm as
opposed to 120 [mu]g/dscm for the existing source cement kiln mercury
standard). And, with the exception of the mercury standard for both new
and existing LWAKs and the total chlorine standard for new LWAKs, they
are also equivalent to or more stringent than the 1999-promulgated
standards, which EPA determined to be generally protective in a
national risk assessment conducted for that
rulemaking.^{231, 232} For today's proposed action, we
conducted a comparative risk analysis of the Phase I replacement
standards to the 1999-promulgated Phase I standards. Specifically, we
compared certain characteristics of the Phase I source universe as it
exists today to the 1999 Phase I source universe to determine if there
were any significant differences that might influence or impact the
potential risk. We focused on the following four key characteristics:
emission rates, stack gas characteristics, meteorological conditions,
and exposed populations. Based on the results of our comparative
analysis, we believe that the risk to human health and the environment
from Phase I sources complying with the proposed replacement standards
will be, for the most part, the same or less than the estimated risk
from sources complying with the 1999-promulgated standards. See Part
Four, Section IX, How Does the Proposed Rule Meet the RCRA
Protectiveness Mandate?.
---------------------------------------------------------------------------

\231\ The 1999-promulgated total chlorine standard for new LWAKs
was 41 ppmv. The proposed replacement standard is 150 ppmv. We do
not view the total chlorine replacement standard as a concern
because the 1999-promulgated total chlorine standard for existing
sources was higher (230 ppmv) and found to be generally protective
in the national risk assessment conducted for that rulemaking. With
respect to risk from mercury for LWAKs, see ``Inferential Risk
Analysis in Support of Standards for Emissions of Hazardous Air
Pollutants from Hazardous Waste Combustors,'' prepared under
contract to EPA by Research Triangle Institute, Research Triangle
Park, NC.
\232\ See Human Health and Ecological Risk Assessment Support to
the Development of Technical Standards for Emissions from Combustion
Units Burning Hazardous Wastes: Background Document, July 1999.

---------------------------------------------------------------------------

[[Page 21326]]

Although the replacement standards are generally equivalent to or
more stringent than both the interim and 1999-promulgated standards, we
cannot assess to what extent this may change the frequency with which
SSRAs are determined to be necessary. In the end, the MACT standards
are technology-based and so, risk analysis notwithstanding, cannot
assure that emissions from each affected source will be protective of
human health and the environment. For example, a particular source
could emit types and concentrations of non-dioxin PICs different from
those we modeled, and so could continue to pose risk not accounted for
in our analysis. Sources' emissions of criteria pollutants, which are
non-HAPs and so are beyond the direct scope of MACT, also could
possibly pose risk which could necessitate site specific risk
assessment.\233\ Another potential example involves emissions of
nonmercury metal HAP by cement kilns and lightweight aggregate kilns.
The semivolatile and low volatile metal thermal emission standards
directly address emissions attributable to the hazardous waste, as
opposed to a source's total HAP metal emissions. Thus, although these
proposed limits reflect MACT, by normalizing the standards to thermal
firing rate (for the appropriate reasons explained earlier), they do
not create a HAP metal ``emissions cap.'' HAP metal emission
contributions from nonhazardous waste fuels and raw materials are not
directly regulated by this type of emission standard, but are rather
controlled appropriately with the particulate matter standard.\234\
---------------------------------------------------------------------------

\233\ See 56 FR at 7145 (Feb. 21, 1991) explaining why there can
be circumstances where a risk-based standard for particulate matter
(a criteria pollutant) for hazardous waste combustion sources may be
needed, and how such a standard could be integrated into the
National Ambient Air Quality Standard implementation process.
\234\ Particulate matter is an appropriate surrogate to control
metal emissions in nonhazardous waste fuels and raw material in lieu
of a numerical metal emission limit because a numerical metal
emission standard may inappropriately control feedrate of HAP metals
in the raw materials and fossil fuels (since such control would be
neither replicable nor duplicable, and is not justified as a beyond-
the-floor standard).
---------------------------------------------------------------------------

In contrast, RCRA permits can address the total emissions from the
combustion unit, assuming an appropriate nexus with hazardous waste
combustion. Thus, for those combustors that must comply with a thermal
emission standard and that feed materials other than hazardous waste,
the permitting authority may decide that an SSRA is appropriate to
determine if additional limits (i.e., a total emissions cap) are
necessary to ensure that all metal HAP emissions from the combustion
unit remain at a level that is protective of human health and the environment.
With respect to Phase II sources, the standards we are proposing in
today's notice are significantly more stringent than the existing
technical standards required under RCRA (40 CFR part 266, subpart H).
To evaluate the protectiveness of the proposed Phase II standards, we
conducted the same comparative risk analysis for Phase II sources that
we conducted for Phase I sources. Specifically, we evaluated the
differences between the 1999 Phase I source universe and the existing
Phase II source universe with respect to the four key source
characteristics mentioned above to determine if there were any
significant differences that might influence or impact the potential
risk. As discussed in the background document, (``Draft Technical
Support Document for HWC MACT Replacement Standards, Volume V:
Emissions Estimates and Engineering Costs'') we estimated emissions for
each facility based on site-specific stack gas concentrations and flow
rates measured during trial burn or compliance tests. We then assumed
that sources would design their systems to meet an emission level below
the proposed standard. For today's proposed standards, the design level
is generally the lower of: (1) 70% of the standard; or (2) the
arithmetic average of the emissions data of the best performing
sources.\235\ We believe the comparative analysis lends support to our
view that the standards for Phase II sources are generally protective.
For a detailed discussion of the comparative risk analysis methodology
and results, see the background document entitled ``Inferential Risk
Analysis in Support of Standards for Emissions of Hazardous Air
Pollutants from Hazardous Waste Combustors,'' prepared under contract
to EPA by Research Triangle Institute, Research Triangle Park, NC.
---------------------------------------------------------------------------

\235\ If available test data in our data base indicate that the
source was emitting below the design level, we assumed that the
source would continue to emit at the levels measured in test.
---------------------------------------------------------------------------

As with the Phase I sources, we cannot reliably predict to what
extent SSRAs will continue to be necessary for Phase II sources once
they have complied with the MACT standards. In view of the standards
alone there are at least three possible scenarios for which SSRAs may
continue to be needed. First, we are proposing thermal emission
standards for liquid fuel-fired boilers. Thus, similar to cement kilns
and LWAKs, permitting authorities may determine that an SSRA is
necessary to ensure that all emissions from liquid fuel-fired boilers
are protective of human health and the environment. Second, we are
proposing that liquid fuel-fired boilers with wet APCD or no APCD and
solid fuel-fired boilers comply with a CO or total hydrocarbon limit as
a surrogate for the dioxin/furan emission standard. Permitting
authorities may determine that an SSRA is necessary for these sources
if there is some concern that the CO or total hydrocarbon limit alone
may not be adequately protective. Third, we are not proposing standards
for all HAPs emitted by Phase II area sources. Instead, consistent with
CAA section 112(c)(6), we are proposing MACT standards only for dioxin/
furans, mercury, carbon monoxide and hydrocarbons, and DRE. For the
remaining metals, particulate matter and TCl, we are providing area
sources with the option of complying with the MACT standards for major
sources or continuing to comply with the existing RCRA technical
standards. Sources that choose to comply with the RCRA standards may
need to consider an SSRA, because the RCRA standards alone may not be
sufficiently protective (i.e., since they do not address the potential
risk from indirect exposures to long-term deposition of metals onto
soils and surface waters). To date, we have identified only three area
sources in the Phase II universe. Thus, the number of sources that
could decide to continue complying with the above-mentioned RCRA
standards is expected to be very limited.
It is useful to note that there are other site-specific factors or
circumstances beyond the standards themselves that can be important to
the SSRA decision making process for an individual combustor. For
example, a source's proximity to a water body or an endangered species
habitat, repeated occurrences of contaminant advisories for nearby
water bodies, the number of hazardous air pollutant emission sources
within a facility and the surrounding community, whether or not the
waste feed to the combustor is comprised of persistent, bioaccumulative
or toxic contaminants, and sensitive receptors with potentially
significantly different exposure pathways, such as Native Americans,
will likely influence a permitting authority's decision of whether or
not an SSRA is necessary. In addition, uncertainties inherent in our
comparative risk analysis and the national risk assessment conducted in
support of the 1999-promulgated

[[Page 21327]]

standards also may influence a permitting authority's decision. For
example, the 1999 national risk assessment contained some uncertainties
regarding the fate and transport of mercury in the environment and the
biological significance of mercury exposures in fish. Another example
relates to nondioxin products of incomplete combustion. Due to
insufficient emissions data and parameter values, the 1999 national
risk assessment did not include an evaluation of risk posed by
nondioxin products of incomplete combustion. See 64 FR 52840 and 52841
for additional discussion of uncertainties regarding the national risk
assessment. Also, the comparative risk analysis conducted in support of
today's action did not account for cumulative emissions at a source or
background exposures from other sources.
3. What Changes Are EPA Proposing With Respect To the Site-Specific
Risk Assessment Policy?
As stated earlier in this section, we recommended in the preamble
to the 1999 rulemaking that permitting authorities evaluate the need
for an SSRA on a case-by-case basis for hazardous waste combustors
subject to the Phase I MACT standards. For hazardous waste combustors
not subject to the Phase I standards, we continued to recommend that
SSRAs be conducted as part of the RCRA permitting process if necessary
to protect human health and the environment. We indicated that the RCRA
omnibus provision authorized permit writers to require applicants to
submit SSRA results where an SSRA was determined to be necessary.
Today, we are proposing to codify the authority for permit writers to
evaluate the need for and, where appropriate, require SSRAs. We are
also proposing to codify the authority for permit writers to add
conditions to RCRA permits that they determine, based on the results of
an SSRA, are necessary to protect human health and the environment. In
doing so, our intent is to change the regulatory mechanism that is the
basis for SSRAs, while retaining the same SSRA policy from a
substantive standpoint. Under this approach, permitting authorities
continue to have the responsibility to ensure the protectiveness of
RCRA permits. We are requesting comment on this proposal.
RCRA sections 3004(a) and (q) require that we promulgate standards
for hazardous waste treatment, storage and disposal facilities and
hazardous waste energy recovery facilities as may be necessary to
protect human health and the environment. RCRA section 1006(b) directs
us to integrate the provisions of RCRA with the appropriate provisions
of the CAA and other federal statutes to the maximum extent
practicable. Thus, to the extent that the RCRA emission standards and
associated requirements promulgated under section 3004(a) or (q) are
duplicative of the CAA MACT standards, section 1006(b) provides us with
the authority to eliminate duplicative RCRA standards and associated
requirements. For this reason, we have provided that most RCRA emission
standards and associated requirements no longer apply to incinerators,
cement kilns, and lightweight aggregate kilns once these sources
demonstrate compliance with MACT requirements. As explained earlier, we
are proposing to do the same in today's notice for solid fuel-fired
boilers, liquid fuel-fired boilers and HCl production furnaces.
Although the Phase I replacement and Phase II standards provide a
high level of protection to human health and the environment, thereby
allowing us to nationally defer the RCRA emission requirements to MACT,
additional controls may be necessary on an individual source basis to
ensure that adequate protection is achieved in accordance with RCRA. We
believe that this will continue to be the case even after the Phase I
replacement and Phase II standards are promulgated as discussed earlier
in this section. Up to this point in time, we have relied exclusively
on RCRA section 3005(c)(3) and its associated regulations (e.g., 40 CFR
270.10(k)) when conducting or requiring a risk assessment on a site-
specific basis. Because risk assessments are likely to continue to be
necessary at some facilities, we are proposing to explicitly codify the
authority to require them on a case-by-case basis and add conditions to
RCRA permits based on SSRA results under the authority of sections
3004(a) and (q) and 3005 of RCRA. We continue to believe that section
3005(c)(3) and its associated regulations provide the authority to
require and perform SSRAs and to write permit conditions based on SSRA
results. Indeed, as explained below, EPA will likely continue to
include permit conditions based on the omnibus authority in some
circumstances when conducting these activities, and state agencies in
states with authorized programs will continue to rely on their own
authorized equivalents, at least for some period of time. However,
since we foresee that SSRAs will likely continue to be necessary at
some hazardous waste combustion facilities, we are proposing to
expressly codify these authorities for the convenience of both
regulators and the regulated community.
We are not proposing that SSRAs automatically be conducted for
hazardous waste combustion units, because we continue to believe that
the decision of whether or not a risk assessment is necessary must be
made based upon relevant site-specific factors associated with an
individual combustion unit and that there are combustion units for
which an SSRA will not be necessary. We further believe that it is the
permitting authority, with information provided by hazardous waste
combustion facilities, that is best equipped to make this decision.
4. How Would the New SSRA Regulatory Provisions Work?
The SSRA regulatory provisions are proposed under both base program
authority (sections 3004(a) and 3005(b)) and HSWA authority (section
3004(q)). Thus, where EPA or a state regulator has determined that a
risk assessment is necessary, the applicability of the new provisions
will vary according to the nature of the combustion unit in question
(whether it is regulated under 3004(q), or only 3004(a) and 3005(b)),
and the authorization status of the state. Depending on the facts, the
new authority would be applicable, or the omnibus provision would
remain the principal authority for requiring site-specific risk
assessments and imposing risk-based conditions where appropriate.
As explained in the state authorization section of this preamble
(see Part Two, Section XIX.C), EPA does not consider these provisions
to be either more or less stringent than the pre-existing federal
program, since they simply make explicit an authority that has been and
remains available under the omnibus authority and its implementing
regulations. Thus, states with authorized equivalents to the federal
omnibus authority will not be required to adopt these provisions, so
long as they interpret their omnibus authority broadly enough to
require risk assessments where necessary. Nonetheless, we encourage
states to adopt these provisions to promote regulatory transparency.
We are proposing to add a paragraph to the general permit
application requirements of 40 CFR 270.10 to specifically allow a
permit writer to require that a permittee or an applicant submit an
SSRA or the information necessary for the regulatory agency to conduct
an SSRA, if one is determined to be necessary. The permit writer may
decide that an SSRA is needed if there

[[Page 21328]]

is some reason to believe that additional controls beyond those
required pursuant to 40 CFR parts 63, 264 or 266 may be needed to
ensure protection of human health and the environment under RCRA. We
are also proposing to allow the permit writer to require that the
applicant provide information, if needed, to make the decision of
whether a risk assessment should be required. In addition, we are
proposing to amend the applicability language of 40 CFR 270.19, 270.22,
270.62, and 270.66 to allow a permit writer that has determined that an
SSRA is necessary for a specific combustion unit to continue to apply
the relevant requirements of these sections on a case-by-case basis and
as they relate to the performance of the SSRA after the source has
demonstrated compliance with the MACT standards.
The basis for the decision to conduct the risk assessment must be
included in the administrative record for the facility and made
available to the public during the comment period for the draft permit.
If the facility, or any other party, files comments on a draft permit
decision objecting to the permitting authority's conclusions regarding
the need for a risk assessment, the authority must respond fully to the
comments. In addition, the risk assessment itself also must be included
in the administrative record and made available to the public during
the comment period for the permit. Any resulting permit conditions from
the SSRA also must be documented and supported in the administrative
record. We are proposing to add a paragraph to 40 CFR 270.32 to address
the inclusion of conditions and limitations in RCRA permits as a result
of the findings of an SSRA.
5. Why Is EPA Not Providing National Criteria for Determining When an
SSRA Is or Is Not Necessary?
We are not proposing national criteria for determining when an SSRA
is necessary. In the preamble to the April 1996 Phase I NPRM, we
provided a list of guiding factors which we later updated and modified
in the preamble to the September 1999 final rulemaking. See 61 FR 17372
and 64 FR 52842. We view these guiding factors as items that, because
they may be relevant to the potential risk from a hazardous waste
combustion unit, could be considered by a permitting authority when
deciding if an SSRA is necessary. We did not, and do not, intend for
them to be definitive criteria from which permitting authorities would
make their decision. As we stated in 1999, we believed that the
complexity of multi-pathway risk assessments precluded the conversion
of these qualitative guiding factors into more definitive criteria.
Since that time, we have reaffirmed our belief that the decision
process regarding SSRAs does not lend itself to the application of
required national criteria. Most combustors may be characterized using
one or more of the qualitative guiding factors we provided in 1999, but
not all. These factors were not intended to be an exclusive list of
considerations, nor do we believe that this decision is necessarily
susceptible to an exclusive list of factors. The decision whether to
require a risk assessment is inherently site specific, and permitting
authorities need to have the flexibility to evaluate a range of factors
that can vary from facility to facility. In addition, it is useful to
recognize that as risk assessment science continues to mature, the
factors may change in terms of relative importance and it may not be
prudent to obligate permitting authorities to an exclusive list that
could not be easily adjusted to keep pace with scientific advancements.
In a study conducted by U.S. EPA Region 4, the guiding factors were
used to rank 13 hazardous waste combustion facilities into high, medium
and low risk potential groupings to ascertain if the factors could be
used as a prioritization tool for determining whether or not an SSRA
was necessary. The region found that all facilities evaluated exhibited
a ``high'' level of concern with respect to at least one or more site-
specific characteristics relating to the guiding factors and that
further analysis was required before the region could be assured that
the source would operate in a manner that is adequately protective
under RCRA. As a result, the region concluded that the guiding factors
alone could not be used to make a protectiveness finding. The region's
study, which is entitled Technical Support Assistance of MACT
Implementation Qualitative Risk Check is available in the docket
(Docket #RCRA-2003-0016) established for today's notice.
Moreover, simply determining whether a combustor fits a particular
guiding factor does not address the complex interplay that may exist
between the guiding factors. Nor, does it measure the level of relative
importance of one factor over another. For example, is the proximity of
potentially sensitive receptors more important than multiple on-site
emission points? For all of these reasons, we believe that codification
of a list of factors would not be appropriate here.
6. What Is the Cement Kiln Recycling Coalition's SSRA Rulemaking Petition?
On February 28, 2002, the Cement Kiln Recycling Coalition (CKRC)
submitted a petition for rulemaking ``Petition Under RCRA Sec. 7004(a)
For (1) Repeal of Regulations Issued Without Proper Legal Process and
(2) Promulgation of Regulations If Necessary With Proper Legal
Process'' to the Administrator containing two independent requests with
respect to SSRAs. First, CKRC requested that we repeal the existing
SSRA policy and technical guidance because it believes that the policy
and guidance ``are regulations issued without appropriate notice and
comment rulemaking procedures.'' Second, CKRC requested that after we
repeal the policy and guidance, ``should EPA believe it can establish
the need to require SSRAs in certain situations, CKRC urges EPA to
undertake an appropriate notice and comment rulemaking process seeking
to promulgate regulations establishing such requirements.''
As stated in the petition, ``CKRC does not believe that these SSRA
requirements are in any event necessary or appropriate.'' In addition,
CKRC disagrees with our use of the RCRA omnibus provision as the
authority to conduct SSRAs or to collect the information and data
necessary to conduct SSRAs and further contends that the regulations
associated with the omnibus provision are insufficient in detail. CKRC
asserts that we have chosen to establish SSRA requirements through
guidance documents. CKRC also raised the following three general
concerns: (1) Whether an SSRA is needed for hazardous waste combustors
that will be receiving a RCRA permit when the combustor is in full
compliance with the RCRA boiler and industrial furnace regulations and/
or with the MACT regulations; (2) How an SSRA should be conducted; and
(3) What is the threshold level for a ``yes'' or ``no'' decision that
additional risk-based permit conditions are necessary. In support of
its petition, CKRC refers to Appalachian Power Co. v. EPA, 208 F.3d
1015 (D.C. Cir. 2000), GE v. EPA, 290 F.3d 377 (D.C. Cir. 2002), and
Ethyl Corporation v. EPA, 306 F.3d 1144 (D.C. Cir. 2002). The petition
is available in the docket established for today's proposed action.
CKRC filed the petition filed under RCRA section 7004(a), which
provides that: ``Any person may petition the Administrator for the
promulgation, amendment, or repeal of any regulation under this Act.
Within a reasonable time following receipt of such a petition, the

[[Page 21329]]

Administrator shall take action with respect to the petition and shall
publish notice of such action in the Federal Register, together with
the reasons therefor.''
Shortly after receiving the petition, we conducted a preliminary
evaluation of CKRC's concerns as stated in the petition.\236\ We
determined that any decision regarding the petition should be made in
coordination with our development of the proposed Replacement MACT
standards for Phase I sources and the proposed new MACT standards for
Phase II sources. Thus, we decided that today's notice was the most
appropriate vehicle to announce and request comment on our tentative
decision concerning the petition.
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\236\ EPA does not consider the request to repeal EPA's guidance
documents to be a valid petition under this section, since the
documents are guidance documents, not regulations. Nonetheless,
because CKRC has also petitioned the Agency to issue regulations,
and to be responsive to issues raised by the regulated community,
EPA has decided to use the procedure established in 40 CFR 260.20
for section 7004 petitions to respond to both of CKRC's requests.
EPA does not concede by relying on the section 7004(a) procedure
that its guidance documents are regulations.
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In the meantime, we believed that it was important to take certain
measures to ensure that the SSRA policy and guidance were being used in
the manner that we had intended. In an April 10, 2003 memorandum from
Marianne Lamont Horinko, Assistant Administrator of the Office of Solid
Waste and Emergency Response, to the U.S. EPA Regional Administrators,
we took two of these measures. First, we requested that the regions
review certain documents (e.g., regional memoranda, policy and guidance
documents, Memoranda of Agreement of Grant Workplans with the states)
to determine if any contained misleading or incorrect information
concerning the SSRA policy and technical guidance. If any were found to
contain misleading or incorrect information, we requested that the
region take immediate measures to clarify or correct the information.
Second, we reiterated, in detail, the appropriate use of the SSRA
policy and guidance for hazardous waste combustors, as well as the
appropriate use of the RCRA omnibus authority as it relates to SSRAs.
In a May 15, 2002, memoranda from Robert Springer, Director of the
Office of Solid Waste, to the RCRA Senior Policy Advisors, we took the
third measure to ensure proper application of the SSRA policy by our
regional permit writers. In this memorandum, we instituted an EPA
headquarters review process of future regional decisions concerning the
need for an SSRA for hazardous waste combustion units seeking a RCRA
permit determination. Specifically, we requested that the regions
provide us with a written summary of the basis for any future decisions
to conduct or not conduct an SSRA. It is our intention that the review
process focus on whether or not permit writers have adequately
supported their decisions. It is important to point out that because
many of the decisions regarding SSRAs are now being made at the state
level, we do not yet know how many regional SSRA decision summaries
will be submitted for our review. Both the April 10, 2003, and May 15,
2003, memoranda are provided in the docket established for today's
proposed action.
EPA is in the process of an additional effort to ensure proper use
of the guidance: we are reviewing the guidance documents themselves,
and, to the extent we find language that could be construed as limiting
discretion, we intend to revise the documents to make clear that they
are non-binding. CKRC indicated in its petition that, in its view, the
documents contain language that could be construed as mandatory. While
EPA does not necessarily agree, and believes that, in context, it is
clear that the guidance in the documents is discretionary, EPA is
nonetheless reviewing the documents to ensure that they are carefully
drafted.
After consideration of the petition, we have made a tentative
decision to partially grant and partially deny CKRC's requests.
Specifically, we are proposing to deny CKRC's request that we repeal
the SSRA policy and guidance and we are proposing to grant CKRC's
request in part by promulgating an explicit authority to require SSRAs
on a site-specific basis using notice and comment rulemaking
procedures. We are requesting comment on our tentative decision.
With respect to CKRC's first request that we repeal the SSRA policy
and guidance, and in response to their specific concern of whether an
SSRA is necessary for combustors that are in full compliance with the
RCRA and/or MACT regulations, we believe that SSRAs do serve a useful
purpose and can be necessary even if a facility is in full compliance
with the existing RCRA and/or MACT technical standards. RCRA requires
that all hazardous waste permits be protective of human health and the
environment. As discussed in the preamble to the 1999 Phase I
rulemaking, the existing RCRA incinerator and Boiler and Industrial
Furnace (BIF) regulations do not address the potential risk that may be
posed from indirect exposures to combustor emissions. See 64 FR 52828,
52839-52842 (September 30, 1999). Further, the technical requirements
associated with the RCRA standards have not been updated to reflect
changes in technology or science for a decade or more and, thus, may
not be sufficiently protective with respect to the potential risk from
direct exposures either. For example, our knowledge regarding the
formation, control and toxicity of dioxin/furans has vastly improved
since the promulgation of the RCRA standards. Therefore, until such
time that hazardous waste combustors comply with the MACT standards,
SSRAs can serve a useful function in ensuring that RCRA combustor
permits will be protective of human health and the environment.
Moreover, even once the MACT standards are fully implemented for
incinerators and BIFs, we believe that there may continue to be
instances in which the permitting authority determines that additional
protections are necessary (e.g., where site-specific conditions
indicate that there may be a potential risk to a sensitive ecosystem or
population), as was explained above in Section 2, Are SSRAs Likely to
be Necessary After Sources Comply with the Phase I Replacement
Standards and Phase II Standards? See also, the explanations at 64 FR
52840-52841. Because there may continue to be a need for SSRAs at some
level, we agree with CKRC that it would be appropriate to explicitly
codify the authority to require SSRAs and SSRA-based permit conditions,
for the sake of regulatory clarity and transparency (although we
continue to believe that the RCRA omnibus provision provides sufficient
authority to conduct SSRAs). EPA requests comment on the variety of
site-specific circumstances that might give rise to the need for an
SSRA, and whether other mechanisms might exist to address those circumstances.
As stated earlier, CKRC raised three general concerns, the first of
which we discussed in the preceding paragraphs. The second concern
relates to the technical recommendations that EPA has offered for
conducting an SSRA. CKRC disagrees with our use of guidance, instead
arguing that EPA's recommendations should have been issued through the
notice and comment rulemaking process.
We disagree that the Agency's technical recommendations either must
or should be issued as a regulation. Risk assessment--especially multi-
pathway, indirect exposure assessment--is a highly technical and
evolving field. Any regulatory approach EPA might codify in this area
is likely to become outdated, or at least artificially constraining,
shortly after promulgation in ways that

[[Page 21330]]

EPA cannot anticipate now. In EPA's view, this is an area that is
uniquely fitted for a guidance approach, rather than regulation. In
fact, across Agency programs, EPA has generally adopted a guidance
approach to risk assessment for exactly this reason. See, e.g.,
Guidelines for Reproductive Toxicity Risk Assessment, 61 FR 56274
(October 31, 1996). EPA's Superfund program has not promulgated
regulations specifying risk assessment methods. Instead, the program
uses site-specific approaches for determining risk, employing methods
offered in EPA guidance as appropriate. The same is true for the RCRA
corrective action program. Although we have attempted to provide our
guidance recommendations in a form that responds to or encompasses many
of the issues that can arise when conducting an SSRA, we recognize that
the flexibility to apply other methodologies, assumptions, or
recommendations has been important to both regulators and the regulated
community in terms of developing an appropriate site-specific
protocol.\237\ For example, some of EPA's technical recommendations may
not be appropriate for the combustion device in question, and risk
assessors must have the flexibility to make adjustments for the
specific conditions present at the source, and the state of risk
assessment science at the time that the SSRA is being performed. As an
obvious example, sources that are located in a dry, desert climate with
no nearby permanent or temporary water bodies of concern should not be
required to include a fisher exposure scenario in an SSRA. In addition,
risk assessors should be free to use the most recent air modeling tools
and toxicity values available rather than be limited to those that may
be out-of-date because a regulation has not been revised following the
development of the new tools or values. Guidance allows for this flexibility.
---------------------------------------------------------------------------

\237\ Permitting authorities, in some cases, have developed
their own guidance methodologies responsive to the specific needs
associated with their facilities. For example, North Carolina,
Texas, and New York have each developed their own risk assessment
methodologies. We think this flexibility employed in the field
supports our judgment that risk assessment methodologies should not
be codified.
---------------------------------------------------------------------------

CKRC points out the EPA codified certain parameters for BIF risk
assessments, to show that it is possible to do so. While EPA agrees it
is possible, the codification in the BIF area is the exception, not the
rule. It has been our experience in implementing the BIF regulations
that codification of certain risk parameters has proven to be overly
constraining because risk science is a continually changing field. For
example, by codifying the toxicity values, risk managers were not able
to utilize more recent values available through EPA's Integrated Risk
Information System (IRIS) \238\ and other resources. Also, shortly
after we codified the air modeling guidelines in support of the risk
parameters and procedures, the Air program revised their air modeling
guidelines, rendering some of the BIF air modeling guidelines
inconsistent and so, they were removed. Further, it is important to
note that at the time of codification, BIF risk assessments were not
intended to address indirect routes of exposure, thus making the
parameters easier to implement. Today, however, risk assessments are
more complex due to the necessary inclusion of multi-pathway and
indirect exposure routes. Given the complexity of multi-pathway and
indirect exposure assessments and the fact that risk science is
continuously evolving, it would be difficult and again, overly
constraining, to codify risk parameters today.
---------------------------------------------------------------------------

\238\ IRIS is a collection of continuously updated chemical
files which contain descriptive and quantitative information with
respect to: oral reference doses and inhalation reference
concentrations (RfDs and RfCs, respectively) for chronic
noncarcinogenic health effects; and hazard identification, oral
slope factors, and oral and inhalation unit risks for carcinogenic
effects. For more information, see http://www.epa.gov/iris/index.html.

---------------------------------------------------------------------------

We also believe that a guidance approach is consistent with the
fact that permit writers must make site-specific decisions whether to
do risk assessments at all. We expect that permit writers will reach
their decisions based on different factors and concerns--in some cases,
factors and concerns that we may not have identified at this time. We
think that it makes little sense to allow this kind of flexibility
regarding whether to do a risk assessment and for what purposes, while
prescribing how one must be conducted if one is required.
CKRC further contends that the guidance is overly conservative and
constitutes ``a confusing pattern of drafts over a number of years in a
seemingly endless fashion'' that has resulted in their members
incurring significant costs. Because of the variability in the many
factors that influence the risk from hazardous waste combustors, the
guidance contains some conservative recommendations and assumptions in
order to address this wide range. However, based on input from users of
the guidance, we have attempted to correct the recommendations and
assumptions that we consider to be overly conservative and, as stated
previously, because they are guidance recommendations and not
requirements, the risk assessor may choose not to follow them. More
recently, we have solicited public and peer review comments on the 1998
guidance,\239\ and are in the process of revising it based on the
comments received. This includes comments CKRC submitted related to the
components of the guidance they contended were overly
conservative.\240\
---------------------------------------------------------------------------

\239\ USEPA. ``Human Health Risk Assessment Protocol for
Hazardous Waste Combustion Facilities'' EPA-520-D-98-001A, B&C.
External Peer Review Draft, 1998. (http://www.epa.gov/epaoswer/
hazwaste/combust/risk.htm)
\240\ We are not responding to the specific comments here, but
will respond to them as part of the public process for developing
the final guidance documents.
---------------------------------------------------------------------------

With respect to CKRC's assertion that the guidance is ``a confusing
pattern of drafts over a number of years'', we acknowledge that we have
issued a number of guidance documents since 1990. However, we disagree
that this has resulted in a confusing pattern of drafts. The
development and release of the guidance documents correspond to three
specific regulatory time periods in the area of hazardous waste
combustion. In addition, the issuance of subsequent versions relates to
the fact that the Agency has repeatedly solicited public and peer
review comments on its technical guidance, and has built upon the
experience of regulators and facilities in using earlier guidance.
In 1990, EPA developed its initial guidance document during the
same time period as the RCRA BIF emission standards. In 1993, we
released an addendum to the 1990 guidance in response to the draft
Hazardous Waste Minimization and Combustion Strategy and our increasing
concerns about the potential impacts from indirect routes of exposure,
and solicited comments from the public and the Science Advisory Board.
A revised document taking into account these comments was issued one
year later.\241\
---------------------------------------------------------------------------

\241\ USEPA. ``Guidance for Performing Screening Level Risk
Analyses at Combustion Facilities Burning Hazardous Wastes'' Draft,
April 1994. USEPA. ``Implementation of Exposure Assessment Guidance
for RCRA Hazardous Waste Combustion Facilities'' Draft, 1994. (These
documents are available as part of the ``Exposure Assessment
Guidance for RCRA Hazardous Waste Combustion Facilities'' EPA530-R-
R-94-021. Copies may be ordered through the National Service Center
for Environmental Publications' Web site at http://www.epa.gov/ncepihom/)

---------------------------------------------------------------------------

At the time that we were developing the Phase 1 MACT standards, we
again updated our combustion risk assessment guidance by releasing a
document specifically addressing human health risk in 1998 and one
addressing ecological risk in 1999, again soliciting public input and
peer review on these

[[Page 21331]]

documents.\242\ For purposes of clarity, both of these documents refer
to all earlier guidance where appropriate and discuss briefly the
progression of the guidance. Although the 1998 human health guidance
and the 1999 ecological guidance provide our current thinking regarding
SSRA methodology for hazardous waste combustors, we noted to our permit
writers that we recommended that they should continue to use the 1994
guidance for those SSRAs that were in progress.
---------------------------------------------------------------------------

\242\ We noted earlier that the 1998 guidance is currently being
revised in consideration of public and peer review comments
received. With respect to the 1999 guidance (USEPA. ``Screening
Level Ecological Risk Assessment Protocol for Hazardous Waste
Combustion Facilities'' EPA-530-D-99-001A, B&C. Peer Review Draft,
1999), we solicited public comment and plan to conduct a peer
review. (http://www.epa.gov/epaoswer/hazwaste/combust/ecorisk.htm)

---------------------------------------------------------------------------

Although CKRC claims to find these guidance documents confusing,
EPA's judgment is that most interested parties--both regulators and the
regulated community--have found the guidance to be useful, and that the
documents have substantially reduced the uncertainty and confusion that
surrounded multi-pathway risk assessments a decade ago. As stated
above, no one is obligated to follow this guidance, and regulators
often depart from it; but EPA believes it has been extremely helpful on
the whole, rather than confusing.
CKRC has alleged that SSRA's typically cost between $200,000 and
$1,000,000 for an individual facility. We are aware that prior to the
release of the 1998 guidance, combustion risk assessments were more
costly than we understand them to be today. For an individual facility,
we do not know to what extent these costs are attributed to the act of
conducting a risk assessment, to recommendations provided in our
guidance, to changes that the facility chose to make during the risk
assessment, or the facility's desire to develop its own site-specific
protocol. Not including the collection and analysis of emission risk
data, we have been advised that the cost of an average SSRA today is
approximately $84,000. (See document entitled Hazardous Waste
Combustion MACT--Replacement Standards: Proposed Rule. Preliminary Cost
Assessment for Site Specific Risk Assessment, November, 2003, as
provided in the docket for today's action.) The emission risk data is
projected to add on average between $57,000 (if the facility collects
its emission risk data at the same time as its emission standards
performance data) and $285,000 (if the facility must conduct a separate
emission test solely for the purpose of collecting data for the SSRA).
Therefore, including emission data collection, the average cost of an
SSRA is between $141,000 and $370,000. This is considerably less than
the cost range provided by CKRC of $200,000 to $1,000,000.
Additionally, EPA's upper bound cost of $370,000 is significantly less
than the upper bound cost of $1,300,000, as reported by CKRC in their
petition (and the attached affidavit).\243\ We believe that the cost of
SSRAs has decreased over time, particularly since the release of the
1998 guidance. This may be in large part because the 1998 guidance is
much more comprehensive than previous guidance documents and because
private software companies have developed computer programs based on
the guidance, which can further decrease costs associated with the risk
calculations for each exposure scenario.
---------------------------------------------------------------------------

\243\ The cost ranges for CKRC include both the cost of risk
assessments and emission data collection. In its petition, CKRC
provided a range of costs ($100,000 to $500,000 for risk assessments
and $100,000 to $500,000 for emission data collection), but also
provided an upper bound cost ($728,297 for a risk assessment and
$588,790 for emission data collection, plus additional permit costs
to equate to $1.3M).
---------------------------------------------------------------------------

CKRC also expressed specific concern that it and its members have
been denied an opportunity to comment on the combustion risk assessment
guidance documents. We strongly disagree with this assertion. We have
repeatedly sought public comment on the guidance documents. For the
1998 human health guidance we not only requested public comment, but
also submitted the document for an external peer review and held a peer
review meeting which was open to the public. Since the peer review
meeting, we have been incorporating both the public and peer review
comments into the human health guidance. While we have not yet
completed this task and released a final document, any member of the
public may at any time discuss any concerns that they have with our
recommendations. In addition, regardless of whether a risk assessor
uses the recommendations provided in our guidance or not, we have
encouraged the permit writer and facility representatives to meet prior
to any analysis to discuss the appropriate risk methodology and data
input needs for an SSRA. Such a meeting allows both the permitting
authority and the facility the opportunity to raise questions and
objections concerning the appropriateness of different methodologies,
assumptions, or default values and their application to the hazardous
waste combustor. Facility representatives and any member of the public
also may comment on the risk assessment methodology as part of the
public comment process associated with the RCRA permit.
The third general concern raised by CKRC in its petition was that
we had not provided a threshold level for a ``yes'' or ``no'' decision
to trigger the need for additional risk-based permit conditions. EPA
agrees that its guidance does not establish a bright-line threshold
level for determining whether to impose additional permit conditions;
such a binding requirement would only be appropriately established
through rulemaking. However, EPA has provided recommendations about the
overall targets for acceptable risk levels. See USEPA. Implementation
of Exposure Assessment Guidance for RCRA Hazardous Waste Combustion
Facilities, Draft, 1994. Moreover, we do not intend to codify our
recommended target levels for some of the same reasons that we are not
proposing to codify the risk assessment technical guidance. Our
recommended target levels provide risk managers with a starting point
from which to determine if a combustor's potential risk may or may not
be acceptable. However, we believe that it is important, and indeed
essential, that risk managers be afforded sufficient flexibility to
apply different target levels as dictated by the circumstances
surrounding the combustor. For example, a risk manager may wish to
apply a more stringent carcinogenic target level for a combustor that
is located in a densely populated area with a high concentration of
industrial emission sources.
In summary, we have made a tentative decision to deny CKRC's
request that we repeal the SSRA policy and guidance and to grant CKRC's
request in part by proposing to codify the authority to require SSRAs.
We are not proposing to codify the SSRA guidance or our recommended
risk methodology for hazardous waste combustors. We are requesting
comment on our tentative decision.

XVIII. What Alternatives to the Particulate Matter Standard Is EPA
Proposing or Requesting Comment On?

As discussed in Part Two, Section IV.C, we are proposing
particulate matter standards as surrogates to control metal HAP.\244\
We are not proposing numerical metal HAP emission standards that would
have accounted for all metal HAP because we generally do not have as
much compliance test

[[Page 21332]]

emissions information in our database for the nonenumerated metal HAP
compared to the enumerated metal HAP,\245\ and because we believe that
a particulate matter standard, in lieu of emission standards that
directly regulate all the metals in all feedstreams, simplifies
compliance activities.
---------------------------------------------------------------------------

\244\ Particulate matter is not a listed HAP pursuant to CAA 112(b).
\245\ ``Enumerated'' metals are those HAP metals that are
directly controlled with an emission limit, i.e., lead, cadmium,
arsenic, beryllium, and chromium. The remaining nonmercury metal HAP
are controlled using particulate matter as a surrogate.
---------------------------------------------------------------------------

Nonetheless, we are today proposing an alternative to the
particulate matter standard for incinerators, liquid fuel-fired
boilers, and solid fuel-fired boilers that is conceptually similar to
the alternative metal emission control requirements that were
previously promulgated for incinerators. We are also requesting comment
on another alternative to the particulate matter standard that would
apply to all source categories that would be subject to particulate
matter standards (i.e., all source categories except hydrochloric acid
production furnaces).
We discuss these two different alternatives below.

A. What Alternative to the Particulate Matter Standard Is EPA Proposing
For Incinerators, Liquid Fuel-Fired Boilers, and Solid Fuel-Fired Boilers?

We promulgated an alternative to the particulate matter standard
for incinerators feeding low levels of metals in the July 3, 2001,
direct final rule. See 66 FR at 35093. Today we propose a simplified
alternative to the particulate matter standard for incinerators, and we
propose to expand the provision to also apply to liquid and solid fuel-
fired boilers. Below, we first describe the alternative that was
originally promulgated for incinerators, after which we describe the
simplified approach and our rationale for proposing it.
The July 3, 2001, final rule allows incinerators to operate under
alternative metal emission control requirements reflecting MACT in lieu
of complying with the 0.015 gr/dscf particulate emission standard.
Under the alternative, no particulate matter emission standard applies
to incinerators under subpart EEE; however, the incinerator remains
subject to the RCRA particulate matter standard of 0.08 gr/dscf
pursuant to Sec. 264.343(c). This is because Clean Air Act standards
can supplant RCRA standards only when the CAA standard is sufficiently
protective of human health and the environment to make the RCRA
standard duplicative (within the meaning of RCRA section 1006 (b)
(3)).\246\ See Part Two, Section XVII.D.
---------------------------------------------------------------------------

\246\ Sources electing to comply with these alternative
requirements thus remain subject to the RCRA PM standard in their
RCRA permit. The RCRA permit must include applicable operating
limits that ensure compliance with the RCRA PM limit.
---------------------------------------------------------------------------

This previously promulgated alternative to the particulate matter
standard has three components. The first component is simply to meet
metal emission limitations for semivolatile and low volatile metals.
The emission limitations apply to both enumerated and non-enumerated
metal HAP, excluding mercury. Enumerated semivolatile metals are those
metals that are directly controlled with the numerical semivolatile
emission standard, i.e., cadmium and lead. Enumerated low volatile
metals are those metals that are directly controlled with the numerical
low volatile metals emission standard, i.e., arsenic, beryllium and
chromium. Non-enumerated metals are those remaining metal HAP:
antimony, cobalt, manganese, nickel, and selenium that are not
controlled directly with an emission standard, but are rather
controlled through the surrogate particulate matter standard.\247\ For
purposes of these alternative requirements, the non-enumerated metals
are classified as either a semivolatile or a low volatile metal, and
included in the calculation of compliance with the corresponding
emissions limit. The level of the standard is the same as that which
applies to other incinerators, but the standard would apply to all
metal HAP, not just those enumerated in the present low volatile metal
and semivolatile metal standards.
---------------------------------------------------------------------------

\247\ Please note that the particulate matter standard is not
redundant to the semivolatile and low volatile metal standards.
Although controlling particulate matter also controls semivolatile
and low volatile metals in combustion gas, these metals can also be
controlled by feedrate control. Thus, sources can achieve the
emission standard for semivolatile and low volatile metals primarily
by feedrate control. In such cases, the particulate matter standard
would be controlling nonenumerated metals primarily.
---------------------------------------------------------------------------

The second component is a requirement for the incinerator to
demonstrate that it is using reasonable hazardous waste metal feed
control, i.e., a defined metal feedrate that is better than the MACT-
defining metal feed floor control level. The third component is a
requirement for the incinerator to demonstrate that its air pollution
control system achieves, at a minimum, a 90 percent system removal
efficiency for semivolatile metals.
Today we propose a simplified version of the above described
alternative in that we propose to require you to comply only with the
first component described above, which is to achieve metal emission
standards for semivolatile and low volatile metals. As discussed above,
the level of the proposed standard is the same as that which applies to
other sources, but the standard would apply to all metal HAP, not just
those enumerated in the present semivolatile and low volatile metal
standards. As with the previously promulgated alternative, no
particulate matter emission standard would apply to these sources under
subpart EEE; however, sources would remain subject to the RCRA
particulate matter standard of 0.08 gr/dscf pursuant to Sec. Sec.
264.343(c) or 266.105.
We propose to eliminate the requirements for you to demonstrate
that: (1) You are using reasonable hazardous waste metal feed control,
i.e., a defined metal feed control that is better than the MACT-
defining feed control level; and (2) your source is equipped with an
air pollution control system that achieves at least a 90 percent system
removal efficiency for semivolatile metals. We believe these two
requirements are not necessary to ensure you are in fact controlling
metals below MACT levels given that all sources electing to comply with
this alternative must limit both the enumerated metals and non-
enumerated metals to levels below the proposed levels that apply only
to enumerated metals. Today's proposed approach, in effect, lowers the
existing semivolatile and low volatile metal emissions limits because
the contribution of nonenumerated metals must be accounted for when
achieving the same numerical semivolatile and low volatile emission
limits. We believe this is appropriate because this effectively lower
emissions limit for enumerated metals compensates for the lower
emission levels that would have been achieved if the source used a
particulate matter control device capable of achieving the particulate
matter standard. Put another way, we regard this emission limitation as
an equivalent means of meeting the standard for HAP metals (except
mercury) already established in the rule.
As discussed above, the approach we promulgated on July 3, 2001
required you, in practice, to feed low levels of metals on a continuous
basis in order to qualify for the alternative. The rule required that
the source's feed control level must be equivalent to or lower than 25%
of the MACT-defining hazardous waste feed control level. We considered
whether it would be appropriate to also apply such a

[[Page 21333]]

qualification requirement to today's proposed alternative.
Unfortunately, the methodology used to calculate today's proposed
emission standards does not base the standards on a specific MACT-
defining feed control level. Thus, we do not have a MACT feed control
level that we can readily use to define an appropriate low feed control
level. We request comment on whether it is appropriate and/or necessary
to establish a minimum feed control level, and if so, how it could be
determined.
1. What Emission Limitation Must Incinerators Comply With Under This
Alternative?
For existing incinerators, the emissions limits under this
alternative would be: (1) A semivolatile metal emission limit of 59
[mu]g/dscm for the combined emissions of lead, cadmium, and selenium;
and (2) a low volatile metal emission limit of 84 [mu]g/dscm for
combined emissions of arsenic, beryllium, chromium, antimony, cobalt,
manganese, and nickel (all emissions corrected to 7% oxygen).
For new sources, the emissions limits would be: (1) a semivolatile
emission limit of 7 [mu]g/dscm for combined emissions of lead, cadmium,
and selenium; and (2) a low volatile emission limit of 9 [mu]g/dscm for
emissions of arsenic, beryllium, chromium, antimony, cobalt, manganese,
and nickel (all emissions corrected to 7% oxygen).
2. What Emission Limitation Must Liquid Fuel-Fired Boilers Comply With
Under This Alternative?
For existing liquid fuel-fired boilers, the emissions limits under
this alternative would be: (1) A semivolatile metal emission limit of
1.1E-5 lb/MM BTU for the combined emissions of lead, cadmium, and
selenium; and (2) a low volatile metal emission limit of 7.7E-5 lb/MM
BTU for combined emissions of arsenic, beryllium, chromium, antimony,
cobalt, manganese, and nickel (all emissions corrected to 7% oxygen).
For new sources, the emissions limits would be: (1) A semivolatile
metal emission limit of 4.3E-6 lb/MM BTU for combined emissions of
lead, cadmium, and selenium; and (2) a low volatile metal emission
limit of 3.6E-5 lb/MM BTU for emissions of arsenic, beryllium,
chromium, antimony, cobalt, manganese, and nickel (all emissions
corrected to 7% oxygen).
3. What Emission Limitation Must Solid Fuel-Fired Boilers Comply With
Under This Alternative?
For existing solid fuel-fired boilers, the emissions limits under
this alternative would be: (1) A semivolatile metal emission limit of
170 [mu]g/dscm for the combined emissions of lead, cadmium, and
selenium; and (2) a low volatile metal emission limit of 210 [mu]g/dscm
for combined emissions of arsenic, beryllium, chromium, antimony,
cobalt, manganese, and nickel (all emissions corrected to 7% oxygen).
For new sources, the emissions limits would be: (1) A semivolatile
metal emission limit of 170 [mu]g/dscm for combined emissions of lead,
cadmium, and selenium; and (2) a low volatile metal emission limit of
190 [mu]g/dscm for emissions of arsenic, beryllium, chromium, antimony,
cobalt, manganese, and nickel (all emissions corrected to 7% oxygen).
4. Why Don't We Offer This Alternative to Lightweight Aggregate Kilns
and Cement Kilns?
This alternative is intended to apply to sources that feed de
minimis levels of metal HAP. We do not believe hazardous waste burning
lightweight aggregate kilns and cement kilns feed these metals at de
minimis levels primarily because raw materials and coal that is co-
fired may contain these metal HAP, and because hazardous waste that is
combusted by sources that receive off-site hazardous waste shipments
(i.e., commercial hazardous waste combustors) typically contain these
metal HAP. Thus, we think that allowing this alternative would not be
of practical significance because we do not believe these sources could
meet the standard. As a result, we are not proposing this alternative
for these source categories.

B. What Alternative to the Particulate Matter Standard Is EPA
Requesting Comment On?

As previously discussed, we do not have sufficient metal HAP
compliance data to calculate MACT floors that would account for all the
nonmercury metal HAP in all feedstreams. We discuss below, however, an
alternative approach to the particulate matter standard that could be
implemented if sources monitor and collect nonmercury metal HAP feed
concentration data prior to the compliance date. Such an approach, if
promulgated, would result in site-specific metal HAP emission limits
that would be dependent, in part, on each source's average feed
concentration levels of metal HAP in their hazardous and nonhazardous
waste feedstreams, and, for energy recovery units, each source's
hazardous waste firing rate. We discuss this alternative below, and we
request comment as to whether this approach is appropriate given the
complexities associated with its implementation. Also see USEPA,
``Draft Technical Support Document for HWC MACT Replacement Standards,
Volume IV: Compliance With MACT Standards,'' March 2004, Chapter 23.9,
for more discussion.
1. What Are the Components of the Total Metal Emissions Limitations?
This total metal emission limitation would regulate all nonmercury
metal HAP with separate semivolatile HAP metal and low volatile HAP
metal emission limits. Each semivolatile and low volatile metal limit
would have separate MACT components that would control and limit
enumerated and nonenumerated metal HAP emissions that are attributable
to: (1) Hazardous waste feedstreams; (2) nonhazardous waste, non-fuel
feedstreams (e.g., cement kiln raw material); and (3) nonhazardous
waste fuels (e.g., coal). Some of these components may or may not apply
depending on the source category. Each semivolatile and low volatile
metal component is converted to a mass emission limitation, and each
source's resultant total metal emissions would be limited to the
summation of each of the applicable components. We describe these MACT
components below.
a. Energy Recovery Units: Allowable Enumerated Semivolatile and Low
Volatile Metal Emissions Attributable to the Hazardous Waste. This
first component limits enumerated metal emissions attributable to
hazardous waste feedstreams from energy recovery units, i.e., liquid
boilers, cement kilns, and lightweight aggregate kilns, and is
equivalent to the enumerated semivolatile and low volatile metal mass
emission rate that would be allowed by today's proposed standards. Each
source's allowable mass emission rate limit for this component would be
equivalent to its associated hazardous waste thermal feed rate
(expressed as million Btu hazardous waste per hour) multiplied by the
proposed semivolatile and low volatile metal thermal emission standard.
b. Solid Fuel-Fired Boilers and Incinerators: Allowable Enumerated
Semivolatile and Low Volatile Metal Emissions Attributable to All
Feedstreams. This second component applies only to solid fuel-fired
boilers and incinerators, and limits enumerated

[[Page 21334]]

metal mass emissions attributable to all feedstreams, i.e., hazardous
waste, nonhazardous waste, and nonhazardous waste fuels. This component
limit is equivalent to the enumerated semivolatile and low volatile
metal mass emission rate that would be allowed by today's proposed
standards. Today's proposed standards for incinerators and solid-fuel-
fired boilers limits total emissions from all feedstreams, and are
expressed as stack gas concentration limits. Each source's allowable
mass emission rate limit for this component would be equivalent to its
gas flowrate multiplied by the proposed standard.
c. All Source Categories: Allowable Nonenumerated Semivolatile and
Low Volatile Metal Emissions Attributable to the Hazardous Waste. This
third component limits nonenumerated semivolatile and low volatile
metal emissions attributable to hazardous waste feedstreams, and is
applicable to all source categories. We currently do not have
sufficient data to calculate a MACT emission limitation for
nonenumerated metals in the hazardous waste. As a result, sources
complying with this alternative would be required to collect three
years of nonenumerated semivolatile and low volatile metal hazardous
waste feed control concentrations.\248\ Incinerators and solid fuel-
fired boilers would be required to collect hazardous waste maximum
theoretical emissions concentrations, and energy recovery units would
be required to collect three years of hazardous waste thermal feed
concentration data for these metal groups.\249\ Each incinerator and
solid fuel-fired boiler's allowable semivolatile and low volatile metal
mass emission rate for this component would be equivalent to its
associated three year average hazardous waste maximum theoretical
emissions concentrations for each metal group multiplied by: (1) One
minus the MACT system removal efficiency; and (2) its associated
volumetric gas flow rate. Each energy recovery unit's allowable mass
emission rate for this component would be equivalent to its associated
three year average hazardous waste thermal feed concentration for each
metal group multiplied by: (1) One minus the MACT system removal
efficiency; and (2) its associated hazardous waste thermal feedrate
(expressed as million Btu hazardous waste per hour). The MACT system
removal efficiency that would be applied separately for semivolatile
metals and low volatile metals would be determined as described in Part
Two, Section VI.G.5 for each source category.
---------------------------------------------------------------------------

\248\ We request comment on how such an approach would work for
new sources, given that new sources may not have historical feed
concentration data at the time they begin operations.
\249\ Each source would be required to calculate its associated
three year average nonenumerated metal hazardous waste
concentrations for both semivolatile metals (selenium) and low
volatile metals (antimony, cobalt, manganese, and nickel) expressed
in either hazardous waste thermal concentrations, i.e., pounds per
million Btus (for energy recovery units) or maximum theoretical
emissions concentrations, i.e., pounds per dry standard cubic feet
(for incinerators and solid fuel-fired boilers).
---------------------------------------------------------------------------

d. Energy Recovery Units: Enumerated and Nonenumerated Metal HAP
Emissions Attributable to Nonhazardous Waste Fuels. The fourth
component limits enumerated and nonenumerated semivolatile and low
volatile metal mass emissions attributable to nonhazardous waste fuels
(e.g., coal) and is applicable to energy recovery units, i.e., cement
kilns, lightweight aggregate kilns, and liquid fuel-fired boilers.
Energy recovery units complying with this alternative would be required
to collect three years of enumerated and nonenumerated semivolatile and
low volatile metal nonhazardous waste fuel thermal feed concentration
levels.\250\ Each source's allowable mass emission rate for this
component would be equivalent to its associated three year average
metal nonhazardous waste fuel thermal feed concentration for each metal
group \251\ multiplied by: (1) One minus the MACT system removal
efficiency for the specified metal group; and (2) its associated
nonhazardous waste thermal feedrate.\252\ As discussed above, the MACT
system removal efficiency that would be applied separately for
semivolatile metals and low volatile metals would be determined as
described in Part Two, Section VI.G.5 for each source category.
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\250\ Sources would not be required to collect three years of
data if the nonhazardous waste fuels such as natural gas do not
contain metal HAP.
\251\ Each source would be required to calculate its associated
three year average metal concentrations in their coal for both
semivolatile metals (lead, cadmium, and selenium) and low volatile
metals (arsenic, beryllium, chromium, antimony, cobalt, manganese,
and nickel) expressed in pounds per million Btu of coal.
\252\ This would be equivalent to a kiln's coal feedrate
expressed in million Btus per hour.
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e. Incinerators and Solid Fuel-Fired Boilers: Nonenumerated Metal
HAP Emissions Attributable to Nonhazardous Waste Fuels. The fifth
component limits nonenumerated semivolatile and low volatile metal mass
emissions attributable to nonhazardous waste fuels (e.g., coal, fuel
oil) and is applicable to incinerators and solid fuel-fired boilers.
Sources complying with this alternative would be required to collect
three years of nonenumerated semivolatile and low volatile metal
nonhazardous waste fuel thermal feed concentrations. Each source's
allowable mass emission rate for this component would be equivalent to
its associated three year average metal nonhazardous waste fuel thermal
feed concentration for each metal group \253\ multiplied by: (1) One
minus the MACT system removal efficiency for the specified metal group;
and (2) its associated nonhazardous waste fuel thermal feedrate
(expressed as million btu per hour). As discussed above, the MACT
system removal efficiency that would be applied separately for
semivolatile metals and low volatile metals would be determined as
described in Part Two, Section VI.G.5 for each source category.
---------------------------------------------------------------------------

\253\ Each source would be required to calculate its associated
three year average nonenumerated metal concentrations in their
nonhazardous waste fuel for both semivolatile metals (selenium) and
low volatile metals (antimony, cobalt, manganese, and nickel)
expressed in pounds per million Btu.
---------------------------------------------------------------------------

f. Incinerators and Solid Fuel-Fired Boilers: Nonenumerated Metal
HAP Emissions Attributable to Nonfuel Nonhazardous Waste. The sixth
component limits nonenumerated metal HAP emissions attributable to
nonfuel nonhazardous waste feedstreams from incinerators and solid
fuel-fired boilers. Sources complying with this alternative would be
required to collect three years of nonenumerated semivolatile and low
volatile metal nonfuel nonhazardous waste feedstream concentration
data, expressed as mass of metal fed in its nonfuel nonhazardous waste
feedstream per total thermal input into the combustor. Each source's
allowable mass emission rate for this component would be equivalent to
its associated three year average metal nonfuel nonhazardous waste
thermal feed concentration for each metal group \254\ multiplied by:
(1) One minus the MACT system removal efficiency for the specified
metal group; and (2) its associated total thermal feedrate (expressed
as million Btus per hour). As discussed above, the MACT system removal
efficiency that would be applied separately for semivolatile metals and
low volatile metals would be determined as described in Part Two,
Section VI.G.5 for each source category.
---------------------------------------------------------------------------

\254\ Each source would be required to calculate its associated
three year average nonenumerated metal thermal feed concentrations
in their nonfuel nonhazardous waste feedstreams for both
semivolatile metals (selenium) and low volatile metals (antimony,
cobalt, manganese, and nickel) expressed in pounds per million Btu.
---------------------------------------------------------------------------

g. Cement Kilns and Lightweight Aggregate Kilns: Enumerated and
Nonenumerated Metal HAP Emissions Attributable to Raw Materials. The

[[Page 21335]]

seventh component limits enumerated and nonenumerated metal HAP
emissions attributable to raw material from cement kilns and
lightweight aggregate kilns. Cement kilns and lightweight aggregate
kilns complying with this alternative would be required to collect
three years of enumerated and nonenumerated semivolatile and low
volatile metal raw material feed concentration data, expressed as mass
of metal fed in raw material per total thermal input into the
kiln.\255\ Each cement kiln and lightweight aggregate kiln's allowable
mass emission rate for this component would be equivalent to its
associated three year average metal raw material thermal feed
concentration for each metal group \256\ multiplied by: (1) one minus
the MACT system removal efficiency for the specified metal group; and
(2) its associated total thermal feedrate. As discussed above, the MACT
system removal efficiency that would be applied separately for
semivolatile metals and low volatile metals would be determined as
described in Part Two, Section VI.G.5 for each source category.
---------------------------------------------------------------------------

\255\ Total thermal input to kiln would include both hazardous
and nonhazardous fuel thermal input.
\256\ Each source would be required to calculate its associated
three year average metal thermal feed concentrations in their raw
material for both semivolatile metals (lead, cadmium, and selenium)
and low volatile metals (arsenic, beryllium, chromium, antimony,
cobalt, manganese, and nickel) expressed in pounds per million Btus.
---------------------------------------------------------------------------

2. Would Sources Still Be Required To Comply With a Particulate Matter
Standard if They Comply With This Alternative?
As previously discussed in Part Two, Section VI.F, we conclude that
today's proposed floor levels can be no higher than the interim
standards because all sources, not just the best performing sources,
are achieving the interim standards. It is not clear whether this
alternative total metal emission limitation is less stringent than the
current interim particulate matter standard for incinerators, cement
kilns, and lightweight aggregate kilns.\257\ As a result, incinerators,
cement kilns, and lightweight aggregate kilns complying with this
alternative would also be required to comply with the interim standard
for particulate matter. Liquid and solid fuel-fired boilers complying
with this alternative would remain subject to the RCRA particulate
matter standard of 0.08 gr/dscf pursuant to Sec. 264.343(c).\258\
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\257\ There is not a direct correlation between particulate
matter emissions and metal emissions given that metal emission
levels are both a function of feed control and particulate matter
control.
\258\ As previously discussed, this is because Clean Air Act
standards can supplant RCRA standards only when the CAA standard is
sufficiently protective of human health and the environment to make
the RCRA standard duplicative (within the meaning of RCRA section
1006 (b) (3)).
---------------------------------------------------------------------------

3. How Would Sources Demonstrate Compliance With This Alternative?
Sources complying with this alternative would be required to
calculate its site-specific semivolatile and low volatile metal mass
emission rate limitation as described above. Each source's emission
limitation would not only be a function of its average three years of
metal concentration data collected, but also would be a function of
either its gas flowrate (for incinerators and solid fuel fired
boilers), hazardous waste thermal firing rate (for cement kilns,
lightweight aggregate kilns, and liquid fuel-fired boilers), and total
thermal input rate (for all sources). As a result each source's mass
emission limitation would vary over time as the dependent variables
change (e.g., a cement kiln's allowable mass emission limitation would
increase if its hazardous waste thermal firing rate increases).
Sources would demonstrate compliance with these site-specific metal
emission rate limitations during its comprehensive performance test and
would establish operating parameter limits on its air pollution control
device to ensure that the source achieves the metal system removal
efficiency that was demonstrated during the test during normal day-to-
day operations. Sources would then establish total metal feedrate
limits that would assure compliance with this site-specific metal
emission limitation. Given that these metal emission limitations may
vary over time, we request comment as to whether these emission
limitations (and associated feedrate operating limits) should be
instantaneous limits based on each source's current operating levels
(e.g., hazardous waste thermal input rate for energy recovery units, or
gas flowrate for incinerators), or rather 12 hour rolling average
limits that would be updated each minute.

XIX. What Are the Proposed RCRA State Authorization and CAA Delegation
Requirements?

A. What Is the Authority for This Rule?

Today's rule amends the promulgated standards located at 40 CFR
part 63, subpart EEE. It amends the standards for the Phase I source
categories--incinerators, cement kilns, and lightweight aggregate kilns
that burn hazardous waste, and it also amends subpart EEE to establish
MACT standards for the Phase II source categories--boilers and
hydrochloric acid production furnaces that burn hazardous waste.
Additionally, this rule amends several RCRA regulations located in 40
CFR part 270 to reflect changes in applicability, addition of a new
permit modification procedure and additions related site-specific risk
assessments and permitting.
1. How Is This Rule Delegated Under the CAA?
Consistent with the September 1999 rule, we recommend that state,
local, and tribal (S/L/T) air pollution control agencies apply for
delegation of this subpart (and all NESHAP) under section 112(l) of the
CAA, if they have not done so already, so that they can exercise
delegable authorities for the final Phase I Replacement standards and
Phase II standards. Delegable authorities are the discretionary
activities, such as approving changes to the reporting schedule, that
are part of each NESHAP. EPA retains some of those authorities, but
allows most to be implemented by those S/L/T agencies who accept
straight delegation of the NESHAP; in this case, subpart EEE. The
delegable authorities, those that can and cannot be delegated, are
described in section 63.1214 of this subpart. (For more information on
delegation of part 63 provisions, see 65 FR 55810-55846.) All major
sources of air pollutants, such as all sources subject to this subpart,
must have a title V operating permit which would contain all applicable
requirements, including those for this subpart. (For more information,
please see 40 CFR part 70.) While S/L/T agencies can implement and
enforce MACT standards through their approved title V programs,
approval of title V programs alone do not allow S/L/T authorities to be
the primary enforcement authority and they cannot exercise delegable
provisions' authorities. An approved title V program means that S/L/T
agencies commit to incorporating all MACT standards into title V
permits as permit conditions and to enforcing all the terms and
conditions of the permit.\259\ Having an approved title V program, for

[[Page 21336]]

instance, does not automatically allow S/L/T agencies to approve test
plans, requests for (minor and intermediate) changes to monitoring,
performance test waivers, document notifications, or other Category I
Authorities (see 40 CFR 63.91(g)(1)(i)). For those S/L/T agencies who
have been previously delegated authority for the MACT standards under
40 CFR part 63 subpart EEE, we encourage you to request approval of the
revisions to emission standards and various other compliance
requirements of today's proposal when promulgated.
---------------------------------------------------------------------------

\259\ Accordingly, S/L/T agencies are required to reopen
existing title V permits that have 3 or more years remaining in the
permit term to include the promulgated standards. If there are less
than 3 years remaining, S/L/T agencies may wait until renewal to
incorporate the standards. Provided that a source is not required to
reopen its title V permit, it must still fully comply with the
promulgated standards (40 CFR 70.7(f)(1)(i)).
---------------------------------------------------------------------------

B. Are There Any Changes to the CAA Delegation Requirements for Phase I
Sources?

With regard to CAA delegation requirements for Phase I sources, we
intend to clarify which provisions in 40 CFR part 63 subpart EEE are
delegable and those that are not in today's Notice of proposed
rulemaking. We recently published a final rule, Clarifications to
Existing National Emissions Standards for Hazardous Air Pollutants
Delegations' Provisions on June 23, 2003 (see 68 FR 37334), that
clarifies and streamlines delegable provisions for each existing
NESHAP. Prior to finalization of this rule, many permitting authorities
and sources alike were left to interpret which Category I authorities
were delegable according to provisions specific to one NESHAP versus
another. In light of this final rule, which outlines the non-delegable
provisions for subpart EEE, some confusion remains today as to which
actions can be taken by a delegated S/L/T agency. Therefore, we intend
to clarify specific actions in subpart EEE that can or cannot be taken
by permitting agencies who have received delegation under 112(l) of the
CAA for subpart EEE.
Sections 63.91(g)(1)(i) and (g)(2)(i) list authorities that are
generally delegable to S/L/T agencies and those that are not,
respectively. These apply to all NESHAP. Similar information contained
in Sec. 63.1214 explains that some of the discretionary authorities,
such as approval of alternative reporting schedules, under subpart EEE,
can be implemented and enforced by a delegated authority. It also lists
the authorities that are retained by EPA and are not delegable to S/L/T
agencies even if they have received delegation for subpart EEE. These
non-delegable authorities are: (1) Approval of alternatives to
requirements in Sec. Sec. 63.1200, 63.1203 through 63.1205, and
63.1206(a); (2) approval of major alternatives to test methods under
Sec. 63.7(e)(2)(ii) and (f); (3) approval of major alternatives to
monitoring under Sec. 63.8(f) and; (4) approval of major alternatives
to recordkeeping and reporting under Sec. 63.10(f). It is important to
note that if the alternatives mentioned in items (2) through (4) are
determined to be minor or intermediate according to the definitions in
Sec. 63.90(a), then they are considered delegable and can be approved
by a S/L/T agency who has been granted authority for subpart EEE.\260\
To aid in the determination of whether a request is major,
intermediate, or minor, we recommend that you consult the September 14,
2000 final rule, Hazardous Air Pollutants: Amendments to the Approval
of State Programs and Delegation of Federal Authorities (65 FR 55810).
The preamble to this rule provides examples, as well as the regulatory
definitions as they exist today in 40 CFR 63.90(a). Additionally, you
may consult a guidance document entitled, How to Review and Issue Clean
Air Act Applicability Determinations and Alternative Monitoring (EPA
305-B-99-004, February 1999).
---------------------------------------------------------------------------

\260\ EPA Regions may choose whether they will or will not
delegate authority to S/L/T agencies to approve minor and
intermediate changes.
---------------------------------------------------------------------------

While Sec. 63.1214(c) and Sec. 63.90(a) provide which authorities
are not delegable for subpart EEE sources and define degrees of
changes, they may not be clear in certain applications. We will address
specific sections in subpart EEE, through the following preamble
discussion and through regulatory amendments, where we believe there is
a need for clarity based upon our experiences with the implementation
of the Phase I standards thus far. Also, there are some alternatives in
subpart EEE that were inadvertently left out of Sec. 63.1214(c) which
we are adding through this Notice of proposed rulemaking.
Beginning with test methods, major alternatives are not delegable.
(See 40 CFR 63.90(a) for definitions of major, intermediate, and minor
changes to test methods.) We noted in Sec. 63.1214(c)(2) that major
alternatives to the test methods as addressed in the general provisions
at Sec. 63.7(e)(2)(ii) and (f) were not delegable, however, we did not
specifically include test methods relevant to subpart EEE. Section
63.1208(b) specifies the test methods sources must use to determine
compliance with emission standards in subpart EEE. This section is
delegable in its entirety to S/L/T agencies who have been delegated
authority for subpart EEE, as long as the request is not a major
change. Additionally, the CEMS required in Sec. 63.1209(a)(1),
although a monitoring requirement, is considered to be a test method
since it serves as the benchmark measurement method for demonstrating
compliance with emission standards. The authority to approve changes to
the CEMS-related requirements is also delegable to S/L/T agencies as
long as the request is not a major change. To summarize, if a source
proposes a major change to a test method specified in Sec. Sec.
63.1208(b) and 63.1209(a)(1), it must send the request to the
appropriate EPA Region and EPA's Office of Air Quality Planning and
Standards,\261\ since major changes to test methods are not delegable.
We are adding Sec. Sec. 63.1208(b) and 63.1209(a)(1), to the
authorities in Sec. 63.1214(c)(2) that are not delegable for major changes.
---------------------------------------------------------------------------

\261\ Send requests to: Conniesue B. Oldham, Ph.D., Group
Leader, Source Measurement Technology Group (D205-02), Office of Air
Quality Planning and Standards, U.S. Environmental Protection
Agency, Research Triangle Park, NC 27711.
---------------------------------------------------------------------------

Consistent with the major alternatives to test methods, major
alternatives to monitoring are not delegable. (See 40 CFR 63.90(a) for
definitions of major, intermediate, and minor changes to test methods.)
We noted in Sec. 63.1214(c)(2) that major alternatives to monitoring
as addressed in the general provisions in Sec. 63.8(f) were not
delegable, but we did not specifically address the relevant monitoring
requirements in subpart EEE. Section 63.1209 specifies the monitoring
requirements sources must use to determine compliance with emission
standards in EEE. Depending upon the pollutant to be monitored, either
a CEMS or COMS is required.
Before discussing whether changes to monitoring in subpart EEE are
delegable, it is important first to review how requests for changes to
monitoring are handled under the general provisions of Sec. 63.8(f).
In general, requests for alternative monitoring follow the same
approach, with respect to delegation authority, as requests for
alternative test methods discussed above; requests that are defined as
major should be sent to the appropriate EPA Region and requests that
are intermediate or minor should be sent to the delegated S/L/T agency.
A request to use other monitoring in lieu of a CEMS is always
considered a major change. However, if a source proposes to use a CEMS
in lieu of an operating parameter, the request may be considered an
intermediate change, so long as the CEMS to be used is regarded as a
``proven technology'' and could be submitted to a S/L/T agency for
approval. The rationale for this is that the use of a CEMS, rather than
monitoring via an operating parameter, provides a better measure of
compliance

[[Page 21337]]

and thus, we want to encourage the use of CEMS when possible. While we
want to encourage the use of CEMS, we recognize that S/L/T agencies may
not always have the technical resources to review these applications,
particularly when there are no federally promulgated performance
specifications for the CEMS. In such cases, we expect that the S/L/T
agency will rely on EPA Regions for approval.
In subpart EEE, Sec. 63.1209, there are two alternative approaches
to monitoring that sources may use. One is located at Sec.
63.1209(a)(5), Petitions to use CEMS for other standards, and the other
is at Sec. 63.1209(g)(1), Alternative monitoring requirements other
than continuous emissions monitoring systems. Section 63.1209(a)(5)
allows sources to request to use CEMS to monitor particulate matter,
mercury, semivolatile metals, low volatile metals, and/or hydrochloric
acid/chlorine gas in lieu of compliance with operating parameter
limits. In these cases, a source would be monitoring the pollutant of
concern and comparing the emissions measurements directly against an
emission limitation rather than comparing the measurements to an
operating parameter. We consider a request under Sec. 63.1209(a)(5) to
be a major change to monitoring and consequently, it is not delegable.
We classify Sec. 63.1209(a)(5) to be a major change (rather than an
intermediate change which can be delegable) mainly because we have not
yet promulgated Performance Specifications for the CEMS that may be
used. In other words, it could be argued that these CEMS do not yet
qualify as fully ``proven technology''. We understand that it could be
argued either way, but for the reasons discussed in the previous
paragraph and as an added measure of consistency, requests to use CEMS
in lieu of operating parameters should be submitted to the EPA Region
for approval. Therefore, we are adding Sec. 63.1209(a)(5) to the
authorities in Sec. 63.1214(c)(2) that are not delegable for major changes.
The other alternative monitoring provision, Sec. 63.1209(g)(1),
allows sources to use alternative monitoring methods, with the
exception of the standards that must be monitored with a CEMS, and to
request a waiver of an operating parameter limit. Section 63.1209(g)(1)
applies to requests for alternative parameter monitoring that involve
the use of a different detector (i.e., thermocouple, pressure
transducer, or flow meter), a different monitoring location, a
different method as recommended by the manufacturer, or a different
averaging period that is more stringent than the applicable standard.
For example, sources equipped with wet scrubbers are required to
establish a minimum pressure drop limit to assure adequate contact
between the gas and liquid. A source may petition to have this
monitoring requirement waived if the manufacturer does not recommend
pressure drop as a critical control parameter that affects the unit's
operating efficiency. Depending upon the type of wet scrubber, an
appropriate minimum limit may be specified for steam injection rate,
disk spin rate, or a maximum temperature limit on liquid and flue gas,
rather than pressure drop. Also, sources could request more stringent
averaging periods in order to ``mirror'' the averaging periods required
under RCRA. This may facilitate an easier transition from RCRA to MACT
during the time period sources may need to comply with both sets of
requirements. Since we do not consider these changes to be major,
requests under Sec. 63.1209(g)(1) should be sent to the delegated S/L/
T agency for approval. Accordingly, we are amending the language in
Sec. 63.1209(g)(1) to specify that a source may submit an application
to the Administrator or a State with an approved Title V program. Also,
we are revising the title under Sec. 63.1209(g)(1) so that it is more
specific regarding its intended use.
Lastly, major alternatives to recordkeeping and reporting also are
not delegable. (See 40 CFR 63.90(a) for definitions of major,
intermediate, and minor changes to test methods.) We noted in Sec.
63.1214(c)(2) that major alternatives to the general provisions of
Sec. 63.10(f) were not delegable, but we did not specifically address
any relevant recordkeeping and reporting requirements in subpart EEE.
Section 63.1211 specifies the recordkeeping and reporting requirements
sources must comply with in subpart EEE. This section is delegable in
its entirety to S/L/T agencies who have been delegated authority to
implement and enforce subpart EEE, as long as the request is not a
major change. It is worthwhile to note that paragraph (e), Data
compression, may be incorrectly interpreted as a major change itself to
the recordkeeping and reporting requirements, because it appears as
though there are no criteria to define fluctuation or data compression
limits. However, this is not the case. In the preamble to the September
1999 final rule (see 64 FR 52961 and 52962), we provided guidance for
preparing a request to use data compression techniques and recommended
fluctuation and data compression limits. This guidance was not affected
by the court's vacatur of portions of this rule, so it remains in
effect. Consequently, this allows permitting authorities to be
consistent in their evaluation of requests. We view paragraph (e) to be
a minor change itself and so a written request to use data compression
techniques can be submitted to a delegated S/L/T agency. We are adding
Sec. 63.1211(a)--(d) to the authorities in Sec. 63.1214(c)(2) that
are not delegable for major changes.
In addition to the clarifications and amendments addressed above,
there are two important delegation issues we would like to emphasize.
The first is simply to remind sources and permitting authorities alike
that, if a provision in this subpart specifies that you may petition or
request that the ``Administrator or State with an approved Title V
program * * *,'' then a state that has not been delegated for that
requirement, but has an approved Title V program, does have the
authority to approve or disapprove the request. For instance, Sec.
63.6(i)(1) and Sec. 63.1213(a) both specify that the ``Administrator
(or a State with an approved permit program)'' can grant a compliance
extension request. The second is that EPA Regions can decide whether or
not to delegate the authority to approve intermediate changes to state
and local agencies. In some cases, a state may have received delegation
to approve only minor changes. Where there is uncertainty, we recommend
that sources try to determine if a request is major, intermediate, or
minor based on the definitions in 40 CFR 63.90(a), and then consult
with their S/L/T agency and/or EPA Region to determine where to submit
the request. Or, sources may submit requests to the S/L/T agency or EPA
Region who will then determine where it should go for approval.

C. What Are the Proposed CAA Delegation Requirements for Phase II Sources?

With respect to CAA delegation requirements for Phase II sources,
they are the same as those for Phase I sources. Since both Phase I and
Phase II MACT standards are located in the same subpart, EEE, the same
delegation provisions apply to both. Generally speaking, authority to
approve alternatives to standards or major changes to test methods,
monitoring, and recordkeeping and reporting are not delegated to S/L/T
agencies. Authority to approve intermediate and minor changes to test
methods, monitoring, and recordkeeping and reporting are delegated to
S/L/T agencies who have been delegated authority to implement

[[Page 21338]]

subpart EEE. All other subpart EEE implementation requirements may be
handled by the delegated S/L/T agency. For specific information, please
refer to the previous section, A.1. What are the clarifications and
changes to CAA delegable authorities for this rule?
How Would States Become Authorized under RCRA for this Rule? Under
section 3006 of RCRA, EPA may authorize qualified states to administer
their own hazardous waste programs in lieu of the federal program
within the state. Following authorization, EPA retains enforcement
authority under sections 3008, 3013, and 7003 of RCRA, although
authorized states have primary enforcement responsibility. The
standards and requirements for state authorization are found at 40 CFR
part 271.
Prior to enactment of the Hazardous and Solid Waste Amendments of
1984 (HSWA), a State with final RCRA authorization administered its
hazardous waste program entirely in lieu of EPA administering the
federal program in that state. The federal requirements no longer
applied in the authorized state, and EPA could not issue permits for
any facilities in that state, since only the state was authorized to
issue RCRA permits. When new, more stringent federal requirements were
promulgated, the state was obligated to enact equivalent authorities
within specified time frames. However, the new federal requirements did
not take effect in an authorized state until the state adopted the
federal requirements as state law.
In contrast, under RCRA section 3006(g) (42 U.S.C. 6926(g)), which
was added by HSWA, new requirements and prohibitions imposed under HSWA
authority take effect in authorized states at the same time that they
take effect in unauthorized states. EPA is directed by the statute to
implement these requirements and prohibitions in authorized states,
including the issuance of permits, until the state is granted
authorization to do so. While states must still adopt HSWA related
provisions as state law to retain final authorization, EPA implements
the HSWA provisions in authorized states until the states do so.
Authorized states are required to modify their programs only when
EPA enacts federal requirements that are more stringent or broader in
scope than existing federal requirements. RCRA section 3009 allows the
states to impose standards more stringent than those in the federal
program (see also 40 CFR 271.1). Therefore, authorized states may, but
are not required to, adopt federal regulations, both HSWA and non-HSWA,
that are considered less stringent than previous federal regulations.
The amendments to the RCRA regulations proposed today in sections
40 CFR 270.10, 270.22, 270.32, 270.42, 270.66, and 270.235 are
considered to be either less stringent or equivalent to the existing
Federal program. Thus, states are not required to modify their programs
to adopt and seek authorization for these provisions, although we
strongly encourage them to do so to facilitate the transition from the
RCRA program to the CAA program and to promote national consistency.
Additionally, EPA will not implement those provisions promulgated under
HSWA authority that are not more stringent than the previous federal
regulations in States that have been authorized for those previous
federal provisions.
The amendments in sections 40 CFR 270.22 and 270.66 in today's
notice are proposed under the HSWA amendments to RCRA. Further, today's
proposed amendment in 40 CFR 270.235 to apply this provision to solid
and liquid fuel-fired boilers and HCL production furnaces, is proposed
under HSWA statutory authority. The amendments to the RCRA regulations
proposed today in sections 40 CFR 270.10 and 270.32 are proposed under
both non-HSWA and HSWA authority, depending on the type of unit to
which these amendments are applied (under HSWA authority if applied to
BIFs or non-HSWA authority if applied to incinerators). Refer to Part
Two, Section XVII.D.4 for a more detailed discussion of the
implementing authorities for proposed regulations in 40 CFR 270.10 and
270.32. The following RCRA sections, enacted as part of HSWA, apply to
today's rule: 3004(o), 3004(q), and 3005(c)(3). As a part of HSWA,
these RCRA provisions are federally enforceable in an authorized State
until the necessary changes to a State's authorization are approved by
us. See RCRA section 3006, 42 U.S.C. 6926. The Agency is adding these
requirements to Table 1 in 271.1(j), which identifies rulemakings that
are promulgated pursuant to HSWA.

Part Three: Proposed Revisions to Compliance Requirements

In this section, we discuss proposed revisions to compliance
requirements that may affect all hazardous waste combustors. We also
request comment on whether we should make revisions to other compliance
requirements, and explain why we conclude not to make revisions to
other compliance requirements that we proposed (or requested comment
on) previously.

I. Why Is EPA Proposing To Allow Phase I Sources To Conduct the Initial
Performance Test To Comply With the Replacement Rules 12 Months After
the Compliance Date?

We propose to allow owners and operators of incinerators, cement
kilns, and lightweight aggregate kilns to commence the initial
comprehensive performance test to comply with the replacement standards
proposed at Sec. Sec. 63.1219, 63.1220, and 63.1221 within 12 months
of the compliance date rather than within six months of the compliance
date. See proposed Sec. 63.1207(c)(3). Owners and operators of solid
fuel-fired boilers, liquid fuel-fired boilers, and hydrochloric acid
production furnaces, however, must commence the initial comprehensive
performance test within six months of the compliance date.
During development of the joint motion by petitioners to the United
States Court of Appeals for the District of Columbia Circuit that
resulted in the Agency promulgating the Interim Standards Rule on
February 13, 2002,\262\ stakeholders representing owners and operators
of incinerators, cement kilns, and lightweight aggregate kilns
requested that we propose to allow them 12 months after the compliance
date to commence the initial comprehensive performance test. These
stakeholders request a 12 month window rather than the six month window
currently required under Sec. 63.1207(c) to give them longer to
amortize the cost of the comprehensive performance test demonstrating
compliance with the Interim Standards before having to retest to
demonstrate compliance with the replacement standards proposed
today.\263\ We believe this request has merit and so are proposing to
allow them to commence the initial comprehensive performance test
within 12 months after the compliance date.\264\
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\262\ See discussion in Part One, Section I.B.1.
\263\ These stakeholders assumed, correctly, that today's
proposed replacement emission standards would be substantially more
stringent than the current (September 1999 Final Rule) standards.
\264\ Please note that this does not affect the compliance date.
You must be in compliance with the replacement standards on the
compliance date, and certify in the Documentation of Compliance that
you have established operating parameter limits that you believe
will ensure compliance with the standards. You must record the
Documentation of Compliance in the operating record by the
compliance date.

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[[Page 21339]]

II. Why Is EPA Requesting Comment on Requirements Promulgated as
Interim Standards or as Final Amendments?

As discussed in Part One, Section I.B., EPA promulgated interim
standards (called the Interim Standards Rule) on February 13, 2002 that
amended compliance and implementation provisions of the September 1999
Final Rule. The amended provisions were specified in a joint motion by
petitioners to the United States Court of Appeals for the District of
Columbia Circuit (the Court). Although petitioners agreed that the
amendments should be promulgated (see 67 FR at 6794), petitioners
requested that EPA reopen certain amended provisions for public comment.
Also as discussed in Part One, Section I.B, EPA promulgated
amendments (called Final Amendments) to the September 1999 Final Rule
on February 14, 2002 that revised certain implementation and compliance
requirements. These amendments were also specified in the joint motion
to the Court, and petitioners requested that EPA reopen specific
amended provisions for public comment.
We discuss these provisions in this section, and reopen them for
public comment. (We note, however, that we are not reopening for
comment any RCRA rules, and are not soliciting comment on any aspect of
those rules, or otherwise reconsidering or reexaming any such rules.
Any references to RCRA rules in the discussion which follows is solely
as an aid to readers.) Although we are not proposing additional
revisions to these provisions, we may determine after review of public
comments on the issues we raise that revisions are appropriate. If so,
we would promulgate those amendments in the Replacement Rule.
Although these provisions currently apply only to incinerators,
cement kilns, and lightweight aggregate kilns, we are proposing today
to apply them to boilers and hydrochloric acid production furnaces as
well. (See Part Two, Sections XIII-XV.) Accordingly, any amendments to
these requirements that we may promulgate would also apply to boilers
and hydrochloric acid production furnaces.

A. Interim Standards Amendments to the Startup, Shutdown, and
Malfunction Plan Requirements

The September 1999 Final Rule required compliance with the emission
standards and operating requirements at all times that hazardous waste
is in the combustion system, including during startup, shutdown, and
malfunctions. Industry stakeholders noted that requiring compliance
with emission standards and operating requirements during startup,
shutdown, and malfunctions is inconsistent with the General Provisions
of subpart A, part 63, that apply to MACT sources (unless alternative
requirements are prescribed for a source category). Stakeholders stated
that it is inappropriate to penalize a source for exceeding emission
standards and operating requirements during malfunctions because some
exceedances are unavoidable and sources are already required to take
corrective measures prescribed in the startup, shutdown, and
malfunction plan (SSMP) to minimize emissions.
In response to industry stakeholder concerns, the Interim Standards
Rule amended the SSMP requirements to: (1) Exempt sources from the
Subpart EEE emission standards and operating requirements during
startup, shutdown, and malfunctions; (2) continue to subject sources to
RCRA requirements during malfunctions, unless they comply with
alternative MACT requirements including expanding the SSMP to minimize
the frequency and severity of malfunctions, and submit the plan to the
delegated CAA authority for review and approval \265\; (3) continue to
subject sources that burn hazardous waste during startup and shutdown
to RCRA requirements for startup and shutdown, unless they comply with
alternative MACT requirements, and require sources to include waste
feed restrictions and operating conditions and limits in the startup,
shutdown, and malfunction plan; (4) require sources to include in the
SSMP a requirement to comply with the automatic hazardous waste feed
cutoff system during startup, shutdown, and malfunctions; and (5) make
conforming revisions to the emergency safety vent opening requirements.
See 67 FR at 6798-6802.
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\265\ These requirements are needed to minimize emissions of HAP
during startup, shutdown, and malfunctions and, thus, help meet our
RCRA mandate to ensure that emissions from hazardous waste
combustors do not pose a hazard to human health and the environment.
Sources may elect either to remain under RCRA control during these
events or to comply under MACT with requirements to develop and
implement a comprehensive and proactive startup, shutdown, and
malfunction plan that is reviewed and approved by the delegated
regulatory authority.
---------------------------------------------------------------------------

In response to Sierra Club's request during development of the
joint motion to the Court, we specifically request comment on the
following issues. Notwithstanding the rationale for revising the
September 1999 Final Rule to exempt sources from the subpart EEE
emission standards and operating requirements during malfunctions,
would it be appropriate to require compliance with those standards and
operating requirements during malfunctions to ensure that owners and
operators have an incentive to minimize the frequency and duration of
malfunctions that result in exceedances of the standards or operating
requirements. Given that most excess emissions would occur during
startup, shutdown, and malfunctions, should the SSMP be submitted for
review by the delegated regulatory authority and made available for
public review under all options for controlling emissions during
startup, shutdown, and malfunctions? Providing a mechanism for public
review may help ensure that the SSMP is complete, proactive, and
provides appropriate corrective measures.\266\ And finally, should the
final rule clarify the definitions of startup, shutdown, and
malfunctions to preclude, for example, an owner or operator incorrectly
classifying an exceedance of an operating limit while hazardous waste
remains in the combustion chamber as a malfunction when, in fact, the
exceedance occurred because of a not infrequent event that could have
been prevented by proper operation and maintenance of equipment?
---------------------------------------------------------------------------

\266\ We also request comment on whether the startup, shutdown,
and malfunction plan should be expanded beyond the scope required
under Sec. 63.6(e)(3) (requiring appropriate corrective measures in
reaction to a malfunction) to address specific, proactive measures
that the owner and operator have considered and are taking to
minimize the frequency and severity of malfunctions.
---------------------------------------------------------------------------

B. Interim Standards Amendments to the Compliance Requirements for
Ionizing Wet Scrubbers

The September 1999 Final Rule required sources to establish a limit
on minimum total power to an ionizing wet scrubber. The Interim
Standards Rule deleted that requirement to conform with the
requirements for electrostatic precipitators given that an ionizing wet
scrubber is essentially an ESP integrated with a packed bed scrubber.
See 67 FR at 6802-03.\267\ In lieu of establishing a limit on the
minimum total power requirement to an ionizing wet scrubber, sources
and delegated CAA authorities will use the alternative monitoring
provisions of Sec. 63.1209(g) to identify appropriate controls for an
ionizing wet scrubber on a site-specific basis. This is

[[Page 21340]]

the same approach that is used for electrostatic precipitators.
---------------------------------------------------------------------------

\267\ EPA voluntarily vacated operating parameter limits for
electrostatic precipitators (and fabric filters) on May 14, 2001.
See 66 FR at 24272. Until new operating parameter limits are
promulgated, sources and delegated CAA authorities will use Sec.
63.1209(g) to establish operating parameter limits for electrostatic
precipitators (and fabric filters) on a site-specific basis.
---------------------------------------------------------------------------

Please note that we are requesting comment today on compliance
requirements for electrostatic precipitators and fabric filters. In
that discussion (see Section III.I below), we explain that we are
proposing to apply the same compliance requirements to both
electrostatic precipitators and ionizing wet scrubbers.

C. Why Is EPA Requesting Comment on the Fugitive Emission Requirements?

The September 1999 Final Rule required sources to control
combustion system leaks by either: (1) Keeping the combustion zone
sealed; (2) maintaining the maximum combustion zone pressure lower than
ambient pressure using an instantaneous monitor; or (3) using an
alternative means to provide control of system leaks equivalent to
maintaining the maximum combustion zone pressure lower than ambient.
After publication of the September 1999 Final Rule, stakeholders
expressed concern that the option to maintain combustion zone pressure
lower than ambient pressure (option 2 above) could result in overly
prescriptive requirements. Stakeholders believed that this regulatory
language could be interpreted to require sources to monitor and record
combustion zone pressure at a frequency of every 50 milliseconds.
Stakeholders also requested that we clarify that combustion system
leaks refers to fugitive emissions resulting from the combustion of
hazardous waste, and not fugitive emissions that originate from
nonhazardous process streams.
In response to these concerns, we proposed amendments to the
combustion system leak provisions on July 3, 2001. See 66 FR at 35132.
We promulgated several revisions in the Final Amendments Rule after
considering stakeholder comments. See 67 FR at 6973.
The amended provisions that we are reopening for public comment
today are discussed below. First, we amended the definition of an
instantaneous pressure monitor to better clarify that the intent of the
combustion system leak requirements is to prevent fugitive emissions
from the combustion of hazardous waste rather than from nonhazardous
feedstreams. The revised definition also clarifies that instantaneous
pressure monitors must detect and record pressure at a frequency
adequate to detect combustion system leak events, as determined on a
site-specific basis. See Sec. 63.1201(a) and Sec. 63.1209(p). Second,
we added a provision that requires sources to specify the method used
to control combustion system leaks in the performance test workplan and
Notification of Compliance. See Sec. 63.1206(c)(5)(ii). Finally, in
response to numerous comments, we added a provision that will allow
sources, upon prior written approval of the Administrator, to use other
techniques that can be demonstrated to prevent fugitive emissions
without the use of instantaneous pressure limits. See Sec.
63.1206(c)(5)(i)(D).
The provision allowing sources, upon prior written approval, to use
other techniques that are demonstrated to prevent fugitive emissions
without the use of instantaneous pressure limits was the most
controversial. Specifically, some stakeholders believe this revised
regulatory language is inappropriate because it suggests sources can
sustain a positive pressure event and still prevent fugitive emissions.
We believe that all positive pressure events do not necessarily result
in fugitive emissions. As discussed in detail in the Final Amendments
Rule, there are state-of-the-art rotary kiln seal designs (such as
shrouded and pressurized seals) which are capable of handling positive
pressures without fugitive releases. However, we believe these kilns
are highly unusual, and that other conventional rotary kilns used in
the hazardous waste combustion industry may not have seals which are
designed for such positive pressure operation. In fact, we believe
that, for most rotary kilns in use today, positive pressure events can
result in fugitive releases. The level of such fugitive releases will
be dependent on factors including the magnitude and duration of the
pressure excursion and the design and operation of the kiln.
Furthermore, one commenter recommends that sources should be
allowed to petition the regulatory official to use an alternative
approach, i.e., an approach that does not require instantaneous
pressure limits, only if they meet specific combustor design criteria.
For example, it may be appropriate to apply this provision only to
sources that we know are designed in manner that would not necessitate
use of instantaneous pressure limits to prevent fugitive emissions
(e.g., kilns with multiple graphite seals with pressurized chambers
between the seals to prevent out-leakage, or overlapping spring plate
seals to form an air seal). We request comment on whether this
specificity is necessary, or whether it is more appropriate to
determine this on a site-specific basis (as is currently required). We
also request comment on whether all the previously discussed combustion
system leak regulatory revisions are appropriate.

D. Why Is EPA Requesting Comment on Bag Leak Detector Sensitivity?

The September 1999 Final Rule required sources equipped with fabric
filters to install a bag leak detection system where the detector has
the capability to detect PM emissions at concentrations of 1.0
milligrams per actual cubic meter, or less. In response to industry
stakeholder concerns that a detector need not be able to detect levels
as low as 1.0 mg/acfm to detect subtle changes in baseline, normal
emissions of PM, we proposed in the July 3, 2001, proposed rule (66 FR
at 35134-35) to allow sources to use detectors with less sensitivity
provided that the detector could detect subtle increases in normal
emissions (e.g., caused by pinhole leaks in the bags). The stakeholders
noted that sources equipped with well designed and operated fabric
filters can have normal, baseline emissions well above 1.0 mg/acfm and
be in compliance with the particulate matter emission standards.
Stakeholders recommended that we revise the bag leak detection
requirements to explicitly allow detectors with lower sensitivity in
lieu of source's having to petition the delegated regulatory authority
under the alternative monitoring provisions of Sec. 63.1209(g)(1) to
receive case-by-case approval. All commenters on the proposed amendment
supported the revision, and we finalized the amendment in the February
14, 2002, Final Amendments. See 67 FR at 6981.
In response to a petitioner's request during development of the
joint motion to the Court, however, we specifically request additional
comment on whether allowing detectors that have a level of detection
that is higher than 1.0 mg/acfm will enable the detector to detect
subtle increases in normal emissions. The petitioner is concerned that
a detector with a level of detection higher than 1.0 mg/acfm may not
have the same sensitivity as a detector that can detect PM at 1.0 mg/
acfm. Thus, petitioner is concerned that the less sensitive detector
may not be able to detect subtle increases in PM emissions due to bag
degredation as readily as a detector that can detect at 1.0 mg/acfm. We
specifically request comment on this issue.
We reopen this issue for comment without prejudice to the existing
regulations which allow for less sensitive bag leak detectors. You may
use less sensitive bag leak detectors until the compliance date for any
change we may make in the final rule.

[[Page 21341]]

E. Final Amendments Waiving Operating Parameter Limits During Testing
Without an Approved Test Plan

The September 1999 Final Rule waived operating parameter limits
during subsequent performance testing under an approved performance
test plan. In response to stakeholder concerns, we addressed two issues
in the Final Amendments: (1) Applicability of operating parameter
limits, established in the Documentation of Compliance, during an
initial performance test conducted without an approved test plan; and
(2) applicability of operating parameter limits, established in the
Notification of Compliance, during subsequent performance tests
conducted without an approved test plan. See 67 FR at 6978.
Regarding the initial performance test, we explained that a source
can revise the operating parameter limits specified in the
Documentation of Compliance at any time based on supporting
information. This information would also be included in the performance
test plan to support deviating from the operating limits established in
the previous Documentation of Compliance. Given that sources operate
after the compliance date until the Notification of Compliance is
submitted under operating limits established in the Documentation of
Compliance, and that the technical support for the operating limits
established in the Documentation of Compliance is the same as would be
included in the test plan, it is appropriate to allow initial
performance testing and associated pretesting without an approved test plan.
Regarding subsequent performance testing, we amended the rule to
waive the operating parameter limits during performance testing and
associated pretesting even when testing without an approved test plan.
We reasoned that stack emissions data obtained during the testing would
document whether the source maintained compliance with the emission
standards. (Please note that during testing, including pretesting,
stack emissions must be documented for any emissions standard for which
the source waives an operating parameter limit.) Absent approval of the
test plan, documentation of potential violation of an emission standard
is nonetheless an ample incentive to operate within the emission standards.
In response to a petitioner's request during development of the
joint motion to the Court, however, we request comment on whether
documentation of stack emissions during subsequent performance testing
and associated pretesting is adequate to ensure compliance with the
emission standards absent an approved test plan.

III. Why Is EPA Requesting Comment on Issues and Amendments That Were
Previously Proposed?

In a July 3, 2001, proposed rule, EPA proposed several revisions to
implementation and compliance requirements, and discussed other
implementation and compliance issues. See 66 FR 35126. We promulgated
several of those amendments in the February 14, 2002, Final Amendments
Rule, and we stated in that rule that we would address the remaining
proposed amendments and other issues in a future rulemaking. See 67 FR
at 6970-71. We discuss below those remaining proposed amendments and issues.
Although these issues and proposed amendments originally pertained
only to incinerators, cement kilns, and lightweight aggregate kilns,
any amendments that we may promulgate subsequent to this notice would
also apply to boilers and hydrochloric acid production furnaces.

A. Definition of Research, Development, and Demonstration Source.

In response to industry stakeholder concerns, EPA requested comment
in the July 3, 2001, proposed rule on approaches to preclude
inappropriate use of the exemption for research, development, and
demonstration sources. See 66 FR at 35128. We indicated we were
considering two approaches: (1) Clearly distinguishing between research
and development sources, and limiting the exemption for demonstration
sources to one year or less; or (2) requiring documentation of how a
source's demonstration of an innovative or experimental hazardous waste
treatment technology or process is different from the waste management
services provided by a commercial hazardous waste combustor.
Two stakeholders provided comments, and both recommended that EPA
not revise the definition of research, development, and demonstration
source. One commenter suggested that EPA should be able to determine if
a source is inappropriately claiming the exemption for research,
development, and demonstration source without amending the regulation.
The other commenter suggested that, rather than amend the regulation,
EPA should reiterate that RCRA regulations continue to apply to exempt
research, development, and demonstration sources.\268\
---------------------------------------------------------------------------

\268\ Hazardous waste research, development, and demonstration
sources remain subject to RCRA permit requirements under Sec.
270.65, which direct the Administrator to establish permit terms and
conditions that will assure protection of human health and the environment.
---------------------------------------------------------------------------

We concur with the commenters and are not proposing to amend the
definition of research, development, and demonstration source.

B. Identification of an Organics Residence Time That Is Independent of,
and Shorter Than, the Hazardous Waste Residence Time

In response to industry stakeholder recommendations, EPA requested
comment in the July 3, 2001, proposed rule on whether it is practicable
to calculate a hazardous waste organics residence time that defines
when organic constituents in solid materials have been destroyed. See
66 FR at 35128-30. Under stakeholders' recommendation, after the
hazardous waste organics residence time expires, sources could comply
with standards the Agency has promulgated under sections 112 or 129 of
the Clean Air Act to control organic emissions for source categories
that do not burn hazardous waste in lieu of the hazardous waste
combustor standards and associated compliance requirements under
subpart EEE, part 63, for dioxin/furan, destruction and removal
efficiency, and carbon monoxide or hydrocarbon emissions.\269\
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\269\ Stakeholders also wanted the hazardous waste residence
time (for organics) to expire as soon as possible to avoid
violations associated with exceedances of an organics emission
standard or associated operating requirement during malfunctions
when hazardous waste remained in the combustion chamber. The rule
has been amended, however, to state that an exceedance of an
emission standard or operating requirement during a malfuncation is
not a violation provided that the source has developed an
appropriate startup, shutdown, and malfuncation plan, and follows
the corrective measures provided by the plan. See 67 FR at 6798-6801.
---------------------------------------------------------------------------

In the July 3, 2001, proposed rule, we raised several concerns
regarding the approach recommended by stakeholders to calculate an
organics residence time, and specifically requested comment on how
these concerns could be addressed. See 66 FR at 35130. Although several
stakeholders provided comment on the discussion we presented in the
July 3, 2001, proposed rule, commenters did not address the concerns we
raised. Rather, commenters generally note that calculation of an
organics residence time for solid waste streams would be difficult to
characterize generically. Accordingly, commenters suggest that the rule
be amended to specifically allow calculation of an organics residence
time on a site-specific basis.
We are reluctant to encourage site-specific petitions to calculate an

[[Page 21342]]

organics residence time, however, given that the concerns we raised in
the July 3, 2001, proposal have not been addressed.\270\ Moreover, we
believe that stakeholders' primary motive for identifying an organics
residence time has been eliminated by the February 13, 2002, amendment
to the rule stating that an exceedance of an emission standard or
operating requirement during a malfunction when hazardous waste remains
in the combustion chamber is not a violation provided that the source
follows the corrective measures provided by an appropriate startup,
shutdown, and malfunction plan.
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\270\ We questioned whether available information on low oxygen
destruction would adequately model destruction under the pyrolytic
conditions that occur within solid matrices and whether it is
practicable to perform valid engineering calculations for multiple
waste streams that are not homogeneous and that contain multiple
organic constituents of concern.
---------------------------------------------------------------------------

For these reasons, we are not proposing an organics residence time
or explicitly encouraging sources to petition the delegated CAA
authority on a site-specific basis to identify an organics residence time.

C. Why Is EPA Not Proposing To Extend APCD Controls After the Residence
Time Has Expired When Sources Operate Under Alternative Section 112 or
129 Standards?

In the July 3, 2001, proposed rule, we proposed to extend
applicability of operating requirements for dry particulate matter
emission control devices before you could switch modes of operation and
become subject to Section 112 or 129 standards for sources that do not
burn hazardous waste. See 66 FR at 35130-32. We proposed to require you
to maintain compliance with applicable emission standards for
semivolatile metals, low volatile metals, and particulate matter,
including the operating parameter limits for dry control systems, after
the hazardous waste residence time has expired until the control device
undergoes a complete cleaning cycle. We were concerned that dry
particulate matter control devices such as electrostatic precipitators
and baghouses retain collected particulate matter contaminated with
waste-derived metals; and dioxin/furan when activated carbon injection
is used. In such cases, we were concerned that waste-derived metals and
dioxin/furan may be emitted at levels exceeding the hazardous waste
combustor emission standards if you were to switch modes of operation
and comply with potentially less stringent alternative MACT standards
for sources that do not burn hazardous waste (e.g., subpart LLL for
cement kilns, section 129 standards the Agency is developing for
commercial and industrial solid waste incinerators, and MACT standards
the Agency is developing for boilers).\271\
---------------------------------------------------------------------------

\271\ Please note that you are subject to the standards under
subpart EEE at all times, including after the hazardous waste
residence time has expired, unless you have established an
alternative mode of operation under Sec. 63.1209(q)(1).
---------------------------------------------------------------------------

Commenters raised several concerns about the practicability of
maintaining compliance with the semivolatile metals, low volatile
metals, and particulate matter standards after the hazardous waste
residence time has expired until the particulate matter device
undergoes a complete cleaning cycle. Commenters explained that it is
difficult to determine when a cleaning cycle has been completed for
multi-field electrostatic precipitators and multi-compartment fabric
filters because fabric filter cleaning is typically a continuous
process, and electrostatic precipitator plate cleaning frequency varies
significantly depending on the plate position within the electrostatic
precipitator. Commenters also stated that the proposed requirement
would encourage more frequent cleaning of electrostatic precipitators
and fabric filters than normal, which could increase emissions of HAP
and adversely affect bag life.
After review of comments and further consideration, we conclude
that it is not necessary to revise the standards to extend
applicability of the operating requirements for dry particulate matter
control devices before you could switch modes of operation and become
subject to MACT standards for sources that do not burn hazardous waste.
We now believe that it is highly unlikely that entrained particulate
matter contaminated with hazardous waste derived metals would be
released from the electrostatic precipitator or fabric filter at rates
higher than when feeding hazardous waste when the source begins
operating under the alternative MACT (or section 129) standards for
sources that do not burn hazardous waste. In addition, incinerators,
cement kilns, and solid-fuel-fired boilers would be subject to
alternative standards and operating limits for particulate matter.
Although lightweight aggregate kilns would not be subject to
alternative standards for particulate matter,\272\ lightweight
aggregate kilns that burn hazardous waste are equipped with fabric
filters where their performance is not highly sensitive to operating
conditions. And, although liquid fuel-fired boilers would not be
subject to alternative Section 129 standards for particulate
matter,\273\ over 80% of liquid fuel-fired boilers that burn hazardous
waste are not equipped with a control device, and only about one third
of those with a control device are equipped with an electrostatic
precipitator or fabric filter. Thus, the absence of particulate matter
controls under the alternative section 129 standards is not a
significant concern.
---------------------------------------------------------------------------

\272\ The Agency determined that lightweight aggregate kilns
that do not burn hazardous waste are not a significant source of HAP
emissions and, thus, that MACT standards are not necessary for that
source category.
\273\ The Agency did not propose PM standards for existing
liquid fuel-fired industrial, commercial, and institutional boilers
and process heaters. See 68 FR 1660.
---------------------------------------------------------------------------

For these reasons, we are not proposing to extend applicability of
the operating requirements for dry particulate matter control devices
before you could switch modes of operation and become subject to MACT
standards for sources that do not burn hazardous waste.

D. Why Is EPA Proposing To Allow Use of Method 23 as an Alternative to
Method 0023A for Dioxin/Furan?

The September 1999 Final Rule requires use of Method 0023A for
stack sampling of dioxin/furan emissions. In response to industry
stakeholder requests, we proposed in the July 3, 2001, proposed rule to
allow you to petition the delegated regulatory authority to use Method
23 found in 40 CFR part 60, appendix A, instead of Method 0023A. See 66
FR at 35137. We are revising the proposal today to allow you to use
Method 23 in lieu of Method 0023A after justifying use of Method 23 as
part of your performance test plan that must be reviewed and approved
by the delegated regulatory authority. See proposed Sec.
63.1208(b)(1)(i)(B). This approach would achieve the same objectives as
a petition, but would be simpler to implement because it would not
require a separate petition/document.
In the July 3, 2001, proposed rule, we explain that Method 0023A is
an improved version of Method 23 in that it can improve the quality
assurance of the method. By analyzing the sampling train front half
catch (filter and probe rinse) separately from the back half catch
(sorbent and rinses), Method 0023A provides quality assurance of
recovery of dioxin/furan contained in solid phase particulate and
collected on the filter and probe. Under Method 23, poor recovery of
dioxin/furan contained in solid phase particulate may go unnoticed
because the front half catch and back half catch are combined before
analysis. This may be of particular

[[Page 21343]]

importance for sources that use activated carbon injection or sources
that have carbonaceous material in particulate matter.
Although Method 0023A can improve quality assurance, it is slightly
more expensive than Method 23 and, in many situations, quality
assurance may not be improved. For example, Method 0023A may not be
warranted in the future if Method 0023A analyses document that dioxin/
furan are not detected, are detected at low levels in the front half of
Method 0023A, or are detected at levels well below the emission
standard, and the design and operation of the combustor has not changed
in a manner that could increase dioxin/furan emissions.
Environmental stakeholders comment that use of Method 23 would
allow sources to emit dioxin/furan in excess of the standards without
being detected. We disagree. Owners and operators seeking to use Method
0023A would be required to document using data or information that
Method 23 would provide front half recoveries comparable to Method 0023A.
Industry stakeholders comment that we should simply revise the rule
to allow use of either method, rather than requiring a petitioning
process to use Method 23. As discussed above (and in the July 3, 2001,
proposal), we believe that there are situations where the quality
assurance and added cost of Method 0023A may be warranted, and, so, are
not proposing to allow use of Method 23 without justification and prior
approval. We agree, however, that the formal petitioning process that
we proposed is not necessary. Rather, we propose today to require you
to justify use of Method 23 as part of the performance test plan that
you submit to the delegated regulatory authority for review and
approval. See proposed Sec. 63.1207(f)(1)(xxv).
In the interim, you may request to use Method 23 in lieu of Method
0023A under Sec. 63.7(e)(2)(i) which allows use of a test method with
minor changes in methodology. You should submit your request and the
supporting justification to the delegated regulatory authority.

E. Why Is EPA Not Proposing the ``Matching the Profile'' Alternative
Approach To Establish Operating Parameter Limits?

In response to stakeholder concerns about the stringency of
calculating most operating parameter limits as the average of the test
run averages of the comprehensive performance test, EPA requested
comment in the July 3, 2001, proposed rule on an alternative approach
to establish operating parameter limits. See 66 FR at 35138-39.
The alternative approach, called ``matching the profile'', was
intended to allow sources to identify limits for operating parameters
that would allow the operating parameters to have the same average
variability as experienced during the comprehensive performance test.
The parameter could exceed the average achieved during the performance
test for a period of time, provided that it was equivalently lower than
the average for the same duration of time.
Commenters generally note that the matching the profile approach
has a significant disadvantage in that multiple limits would be
established for each parameter. Accordingly, commenters recommend that
we not include this approach in the regulation, but rather continue to
offer it as guidance. Moreover, commenters note that sources can
request approval of alternative monitoring approaches under Sec.
63.1209(g)(1), and they are concerned that codification of only one
approach, and particularly an approach with potentially limited
utility, could lead the delegated CAA authority to conclude incorrectly
that other approaches may not be appropriate.
We believe that this matter is best dealt with on a site-specific
basis, but note that by specifying one approach in the rule, we do not
mean to preclude use of a different approach pursuant to Sec.
63.1209(g)(1). Sources thus may request approval of the profiling
approach, or another approach, to establish operating limits on a site-
specific basis under Sec. 63.1209(g)(1).

F. Why Is EPA Not Proposing To Allow Extrapolation of OPLs?

In response to industry stakeholder concerns, we requested comment
in the July 3, 2001, proposed rule on whether the rule should allow
extrapolation of an operating parameter limit to a higher limit using a
site-specific, empirically-derived relationship between the parameter
and emissions of the pollutant in question.\274\ See 66 FR at 35139-40.
We also requested comment on whether the rule should allow use of
established engineering principles that define the relationship between
operating parameter and emissions to extrapolate operating limits and
emissions in lieu of a site-specific, empirically-derived relationship.
---------------------------------------------------------------------------

\274\ Please note that the rule already allows extrapolation of
mercury feedrates (Sec. 63.1209(l)(1)(i)) and semivolatile and low
volatile metal feedrates (Sec. 63.1209(n)(2)(ii)).
---------------------------------------------------------------------------

Industry stakeholders are concerned that the rule inappropriately
penalizes sources that achieve comprehensive performance test emission
levels well below the standard by requiring them to establish operating
limits based on performance test operations at those low emission
levels. They note that operating under conditions to artificially
increase emissions during testing (e.g., by detuning emission control
equipment) may not be feasible or desirable from a worker/public health
and cost perspective.
Although stakeholders acknowledge that they may request such
extrapolation as an alternative monitoring approach under Sec.
63.1209(g)(1), they note that explicitly defining an extrapolation
approach in the rule may better facilitate their efforts to obtain
approval from the delegated regulatory authority.
Several industry stakeholders agreed with the principle of
extrapolation as we discussed it in the July 3, 2001, notice, but
disagreed with the requirements for, and limits on, extrapolation that
we recommended. Several other stakeholders oppose the use of
extrapolation generally because of concern that it is difficult to
define completely and accurately the relationship between an operating
parameter and emissions.
Given the extent of the issues associated with explicitly providing
for extrapolation of operating parameter limits, particularly on a
categorical rather than a site-specific level, and given that you
already have the ability to request approval of extrapolation
procedures under Sec. 63.1209(g)(1), we are not proposing to revise
the rule to explicitly allow extrapolation. We believe that
extrapolation must be justified by a site-specific analysis.

G. Why Is EPA Proposing To Delete the Limit on Minimum Combustion
Chamber Temperature for Dioxin/Furan for Cement Kilns?

In response to stakeholder concerns that it is technically
impracticable for cement kilns to establish a minimum combustion
chamber temperature based on the average of the test run averages for
each run of the comprehensive performance test, EPA requested comment
in the July 3, 2001, proposed rule on whether the rule should continue
to require cement kilns to establish and comply with a minimum
combustion chamber temperature limit. See 66 FR at 35140.
We received a total of five comments to the July 3, 2001, proposed
rule. Three commenters opposed deleting the requirement for cement
kilns to establish and comply with a minimum combustion chamber temperature.

[[Page 21344]]

Currently, cement kilns are required to establish a minimum combustion
chamber temperature as an operating parameter limit to ensure
compliance with the destruction and removal efficiency and dioxin/furan
standards. See Sec. Sec. 63.1209(j)(1) and (k)(2). These commenters
generally cited the need for monitoring combustion chamber temperature
by noting that combustion chamber temperature is a principal factor in
ensuring combustion efficiency and destruction of toxic organic compounds.
Two commenters support deleting the minimum combustion chamber
temperature requirements. Commenters state that a cement kiln
inherently controls the kiln temperature to produce clinker because the
required material temperatures must exceed approximately 2,500[deg]F
with combustion gas temperatures higher still. These commenters note
that a cement kiln operates well above minimum temperatures required to
destroy the organic compounds in the hazardous waste, and, therefore, a
minimum combustion chamber temperature limit is not necessary to
control organic hazardous air pollutant emissions.
Commenters also state that combustion chamber temperatures cannot
be maintained at low enough levels for the duration of the
comprehensive performance test to establish workable operating limits
that would allow them to burn hazardous waste fuels economically
without frequent waste feed cutoffs because of potential exceedances of
the limit. Commenters indicate that combustion chamber temperature
levels are fairly constant within a narrow range and note that there is
a very narrow range of temperatures and feed composition in which a
cement kiln must operate in order to produce quality clinker and a
marketable product. Moreover, commenters state that cement kiln
operators must take extreme actions, including potentially equipment-
damaging steps, to lower kiln temperatures to establish an economically
viable minimum combustion chamber limit. Finally, commenters indicate
that these problems are compounded by the requirement in the MACT rule
to establish the hourly rolling limit based on the average of the test
run averages (Sec. Sec. 63.1209(j)(1)(ii) and (k)(2)(ii)).
We are not proposing to delete the requirement for cement kilns to
establish and comply with a minimum combustion chamber temperature to
help ensure compliance with the destruction and removal efficiency
standard. Even though we remain reluctant to delete this requirement,
commenters may, if they choose, provide additional comments on whether
the rule should continue to require cement kilns to establish a minimum
combustion chamber temperature limit as specified in Sec.
63.1209(j)(1).
We are, however, proposing to delete the requirement to establish a
minimum combustion chamber temperature limit for dioxin/furan under
Sec. 63.1209(k)(2). As mentioned above, sources are currently required
to establish a minimum combustion chamber temperature as an operating
parameter limit for both the destruction and removal efficiency and
dioxin/furan standards. This proposed amendment would not affect the
requirement for cement kilns to establish a minimum combustion chamber
temperature under Sec. 63.1209(j)(1) during the destruction and
removal efficiency demonstration. Currently, the destruction and
removal efficiency demonstration need be made only once during the
operational life of a source provided that the design, operation, and
maintenance features do not change in a manner that could reasonably be
expected to affect the ability to meet the destruction and removal
efficiency standard. See Sec. 63.1206(b)(7). If a facility wishes to
operate under new operating parameter limits that could be expected to
affect the ability to meet the destruction and removal efficiency
standard, then the source will need to conduct another destruction and
removal efficiency test. In addition, if a source feeds hazardous waste
at locations other than the flame zone, the destruction and removal
efficiency demonstration must be verified during each comprehensive
performance test and new operating parameter limits must be established.
Sources that fire hazardous waste only at the flame zone (i.e., the
kiln end where clinker product is normally discharged) are required to
make only one destruction and removal efficiency demonstration test
during the operational life of the kiln. During this destruction and
removal efficiency demonstration test, the source would set a minimum
combustion chamber temperature limit under Sec. 63.1209(j)(1) that
would be the limit for the operational life of the kiln. However, as
the rule is currently written, such sources would need to establish a
minimum combustion chamber temperature limit during subsequent
comprehensive performance tests for the dioxin/furan test under Sec.
63.1209(k)(2). The source would be required to comply with the more
stringent (higher) of two minimum combustion chamber temperature
limits, which could lead to a situation where the controlling minimum
combustion chamber temperature limit is based on the dioxin/furan test
rather than the destruction and removal efficiency demonstration.
We believe that this may be an inappropriate outcome given that the
operating limit for minimum combustion chamber temperature is a more
important parameter to ensure compliance with the destruction and
removal efficiency standard than to ensure compliance with the dioxin/
furan standard. Our data indicate that limiting the gas temperature at
the inlet to the particulate matter control device, an operating
parameter limit established during each comprehensive performance test
(Sec. 63.1209(k)(1)), is a critical dioxin/furan control parameter. We
are, therefore, inviting comment on deleting the requirement to
establish a minimum combustion chamber temperature limit when complying
with the dioxin/furans standard. This proposed amendment does not
affect the other operating parameter limits under Sec. 63.1209(k) that
must be established for dioxin/furan such as establishing a limit on
the gas temperature at the inlet to the particulate matter control device.
For cement kilns that fire hazardous wastes at locations other than
the flame zone, the current requirements would effectively remain the
same. Given that a source conducts the destruction and removal
efficiency demonstration and dioxin/furan test simultaneously and that
a source is also required to establish a minimum combustion chamber
temperature limit when demonstrating compliance with and establishing
operating parameter limits for the destruction and removal efficiency
standard, the minimum combustion chamber temperature limits is
effectively retained.

H. Why Is EPA Requesting Additional Comment on Whether To Add a Maximum
pH Limit for Wet Scrubbers To Control Mercury Emissions?

We requested comment in the July 3, 2001, proposed rule as to
whether it is appropriate to establish a limit on maximum pH to control
mercury. See 66 FR at 35142-43. We are requesting additional comment
today on this issue given the results of a recent study indicating that
increasing the pH of scrubber liquid can increase mercury emissions.

[[Page 21345]]

1. What Were the Major Comments on the Discussion in the July 3, 2001,
Proposed Rule?
One commenter supports placing limits on the maximum pH of wet
scrubber liquids for mercury control, but did not provide any
additional rationale on the technical validity of the limit. Other
commenters oppose the imposition of a maximum pH limit. One commenter
wants to see stronger evidence that pH has an impact, and suggests a
reproposal is needed. Another suggests that EPA conduct source testing
to confirm that pH has an impact. Others suggest that if EPA continues
to believe that wet scrubber operating parameter limits are important
for mercury control, then the wet scrubber mercury operating parameter
limits should be determined on a case-by-case basis because the
relationship between mercury control and wet scrubber pH is not well
established and there are numerous other factors that affect mercury
control in wet scrubbers, especially for facilities that burn waste
with various chemical compositions.
2. What Is the Rationale for Considering a Maximum pH Limit To Control
Mercury?
The use of a low pH liquid scrubber solution has been suggested to
be beneficial for mercury control because it helps prevent the re-
release of captured mercury. Ionic mercury (Hg⁺\2\) is
highly soluble in wet scrubber liquid; as opposed to Hg\o\, which has a
very low solubility in a typical water/alkali scrubber solution. Once
absorbed, Hg⁺\2\ can be reduced to Hg\o\ by compounds in the
liquid scrubber solution such as SO2 and HSO3.
Hg\o\ may then be revolatilized back into the stack gas. This is
supported by numerous observations of Hg\o\ at the wet scrubber outlet
which are higher than Hg\o\ at the scrubber inlet
^{275, 276, 277}. These studies suggest that the low scrubber
liquid pH prevents captured mercury from revolatilizing from the
scrubber liquid by: (1) limiting the capture of reducing agents; and
(2) favoring the formation of stable mercury-chlorine compounds such as
HgCl2 due to available Cl^-. In contrast, other
studies postulate that a high scrubber liquid pH might actually be
beneficial for the control of mercury, particularly elemental Hg \278\.
Basic, high pH solutions have the increased ability to absorb chlorine
gas. Dissolved chlorine gas is suggested to enhance the scrubber's
ability to oxidize and capture Hg\o\ (specifically, dissolved chlorine
gas dissociates in basic solutions to produce OCl^- ions
which oxidize Hg\o\ to soluble Hg⁺\2\). In contrast, the
presence of hydrogen chloride or sulfur as SO2 or
H2SO3 in the scrubber solution reduces the liquid scrubber
pH, reduces OCl^-, and reduces the Hg\o\ oxidative potential
of the scrubber liquid.
---------------------------------------------------------------------------

\275\ B. Siret and S. Eagleson, ``A New Wet Scrubbing Technology
for Control of Elemental (Metallic) and Ionic Mercury Emissions,''
Proceedings of 1997 Conference on Incineration and Thermal Treatment
Technology, pp. 821-824, 1997.
\276\ G. T. Amrhein, G. Kudlac, D. Madden, ``Full-Scale Testing
of Mercury Control for Wet FGD Systems,'' Presented at the 27th
International Technical Conference on Coal Utilization and Fuel
Systems, Clearwater, Fl, March 4-7, 2002.
\277\ C.S. Krivanek, ``Mercury Control Technologies for MWCs:
The Unanswered Questions,'' 1993 Air and Waste Management Sponsored
Municipal Solid Waste Combustor Specialty Conference, 1993.
\278\ W. Linak, J. Ryan, B. Ghorishi, and J. Wendt, ``Issues
Related to Solution Chemistry in Mercury Sampling Impingers,''
Journal or Air and Waste Management Association, Vol. 51, pp. 688-
698, May 2001.
---------------------------------------------------------------------------

Although limited test data from full-scale coal fired boiler
evaluations indicate an inconsistent impact of scrubber liquid pH on
mercury control,\279\ a recent study \280\ confirms that ionic mercury
(e.g., HgCl2) that is initially captured in the scrubber can
be reduced in the liquid to elemental Hg (i.e., H\o\) and then
revolatilized to the stack gas. The study concludes that the reduction
of ionic mercury in the liquid is likely due to dissolved sulfur
compounds and that decreasing the pH of the liquid will decrease the
reduction process and subsequently decrease mercury emissions. This new
work is additional evidence that a maximum pH limit might be
appropriate, especially if sulfur is present in feeds.
---------------------------------------------------------------------------

\279\ For example, McDermott Technology (McDermott Technology,
Internet Web page at http://www.mcdermott.com on ``Mercury
Emission Results,'' date unknown) report no impact, while DeVito and
Rosenhoover (M. DeVito and W. Rosenhoover, CONSOL Coal Inc., ``Flue
Gas Hg Measurements from Coal-fired Boilers Equipped with Wet
Scrubbers,'' date unknown) observe that mercury control efficiency
appears to increase with increasing pH.
\280\ J. Chang and S. Ghorishi, ``Simulation and Evaluation of
Elemental Mercury Concentration Increase in Flue Gas Across a Wet
Scrubber,'' Environmental Science and Technology, Vol 37, No. 24,
2003, pp. 5763-5766.
---------------------------------------------------------------------------

Other recent work indicates that there are numerous factors that
influence the control of mercury in wet scrubbers. Mercury speciation
in the flue gas is vitally important to the ability to control mercury
in wet scrubbers. In hazardous waste combustor flue gases, mercury
tends to be predominately in two forms: (1) elemental (Hg\o\); and (2)
ionic (Hg⁺\2\, typically as HgCl2). Speciation
depends on numerous factors including the presence of chlorine or
sulfur, both of which are reactive with mercury. For example, increased
levels of chlorine may increase the amount of HgCl2 and
reduce the amount of Hg\o\. This might suggest that a minimum chlorine
feedrate limit is needed to ensure Hg scrubber efficiency is
maintained, which is counter to the maximum chlorine feedrate limit
used to control emissions of total chlorine and semivolatile and low
volatile metals. Speciation is also affected by the flue gas
temperature cooling profile, which can impact mercury reaction
kinetics. For example, rapid cooling may limit the equilibrium
formation of HgCl2 (i.e., super equilibrium levels of Hg\o\
can survive from rapid cooling). This might suggest that a maximum flue
gas cooling limit is needed, which is counter to that for controlling
dioxin/furan.
Control of mercury in wet scrubbers is also affected by the
scrubber liquid chemical composition. As discussed above, scrubber
liquid composition has a dramatic impact on the control of mercury.
Specifically, the presence of reducing compounds such as SO2
and HSO3 can lead to increased mercury emission by reducing
soluble HgCl2 to insoluble Hg\o\ which can be desorbed while
oxidative compounds such as chlorine gas and special oxidation
additives such as NaClO2, acidified KMnO3,
Na2S, and TMT (tri-mercapto-triazine) would generally help
control mercury emissions by inhibiting reduction of HgCl2
to Hg\o\ and/or enhancing the capture of Hg\o\.
Finally, control of mercury in wet scrubbers is affected by the
scrubber liquid to gas ratio.
Given the recent study discussed above indicating that increasing
the pH of scrubber liquid can increase mercury emissions, we request
additional comment on whether it would be appropriate to establish a
limit on the maximum pH of scrubber liquid to ensure compliance with
the mercury emission standard. We also request comment on issues
relative to establishing and complying with both a maximum limit on pH
to control mercury emissions and a minimum limit on pH to control total
chlorine. For example, you would establish the maximum and minimum pH
limits under separate performance tests. You would establish the
minimum pH limit during a performance test to demonstrate compliance
with the total chlorine standard while you would establish the maximum
pH limit during a performance test to demonstrate compliance with the
mercury standard. In addition, we request comment on the anticipated
range of pH levels between the maximum and minimum limits and whether
the range could potentially be small enough to inhibit operations
substantially. For example, if the pH

[[Page 21346]]

required to achieve your desired scrubber control efficiency for total
chlorine (i.e., the minimum pH limit) is just below the pH level
required to achieve your desired control efficiency for mercury (i.e.,
the maximum pH limit), you may have limited operating flexibility.
Finally, we note that, in the interim until we determine whether to
promulgate a maximum pH limit to control mercury emissions, site-
specific or other information may lead the delegated regulatory
authority to conclude under Sec. 63.1209(g)(2) that a limit on the
maximum pH of wet scrubber liquid may be warranted to ensure compliance
with the mercury emission standard.

I. How Is EPA Proposing to Ensure Performance of Electrostatic
Precipitators, Ionizing Wet Scrubbers, and Fabric Filters?

If your combustor is equipped with a fabric filter, you would be
required to use the bag leak detection system under Sec.
63.1206(c)(7)(ii) to ensure performance of the fabric filter is
maintained in lieu of operating parameter limits.\281\ In addition, we
propose to revise the bag leak requirements under Sec.
63.1206(c)(7)(ii) to require you to operate and maintain the fabric
filter such that the bag leak detection system alarm does not sound
more than 5 percent of the operating time during a 6-month period.
---------------------------------------------------------------------------

\281\ As discussed below in the text, we propose to revise the
current rules to delete the exemption for cement kilns from the bag
leak detection system requirements.
---------------------------------------------------------------------------

If your combustor is equipped with an electrostatic precipitator or
ionizing wet scrubber, we propose to give you the option of: (1) Using
a particulate matter continuous emissions detector for process
monitoring to signal when you must take corrective measures to address
maintenance or other factors causing relative or absolute mass
particulate matter loadings to be higher than the levels achieved
during the performance test; or (2) establishing site-specific
operating parameter limits. If you choose to use a continuous emissions
detector, you must not exceed the alarm set-point you establish based
on the performance test more than 5 percent of the operating time
during a 6-month period. If you choose to establish site-specific
operating parameter limits, you must link each limit to the automatic
waste feed cutoff system.
1. What Is the Background of this Issue?
The current regulations require you to establish site-specific
operating parameter limits to ensure performance of electrostatic
precipitators, ionizing wet scrubbers, and fabric filters. See Sec.
63.1209(m)(1)(iv).\282\ Regulatory officials review and approve those
operating parameter limits and may require additional or alternative
limits under Sec. 63.1209(g)(2).
---------------------------------------------------------------------------

\282\ Please note that Sec. 63.1209(m)(1)(iv) inadvertently
indicates that the requirement to establish site-specific operating
limits applies to control devices other than ionizing wet scrubbers,
baghouses, and electrostatic precipitators. We should have revised
that paragraph to require site-specific operating parameter limits
for those control devices when we revised paragraph (m)(1) to delete
the operating parameter limits for those devices. The delegated
regulatory authority can use Sec. 63.1209(g)(2) to require you to
establish site-specific operating parameter limits for those control
devices prior to the effective date of the final rule based on
today's proposed rule.
---------------------------------------------------------------------------

In the July 3, 2001 proposed rule, we requested comment on how to
establish prescriptive requirements to ensure performance of these
control devices. See 66 FR at 35143-45. We requested comment on four
approaches to ensure performance of electrostatic precipitators: (1)
Requiring an increasing kVA pattern across the electrostatic
precipitator; (2) limiting kVA on only the back \1/3\ of fields; (3)
use of a CMS that measures relative particulate matter loadings; and
(4) use of predictive emission monitoring systems. These approaches
would also be applicable to ionizing wet scrubbers. We also requested
comment on whether and how cell pressure drop should be used to ensure
performance of fabric filters.
We received comments in favor of and opposing most of these
approaches.\283\ Some stakeholders also recommend other approaches. One
commenter favors use of specific power as an operating parameter for
electrostatic precipitator performance. Specific power is the secondary
power/gas flow rate. Another commenter suggests continuing with
establishing site-specific operating parameter limits.
---------------------------------------------------------------------------

\283\ USEPA, ``Response to Comments on July 2001 Proposed
Rule,'' March 2004.
---------------------------------------------------------------------------

2. What Is the Rationale for Proposing to Revise the Compliance
Requirements for Fabric Filters?
After reviewing comments and further investigation, we conclude
that controls in addition to a bag leak detection system are not needed
to ensure performance of fabric filters. Use of pressure drop to ensure
performance is problematic for reasons we discussed in the July 3, 2001
proposed rule. Moreover, the bag leak detection system provides a
direct measure of small (and greater) increases in particulate matter
loading that enable you to take immediate corrective measures.
We conclude, however, that the bag leak detection system
requirements under Sec. 63.1206(c)(7)(ii) are not prescriptive enough
to ensure proper operation and maintenance of the fabric filter.
Current provisions require you to take immediate corrective measures
when the bag leak detection system alarm sounds, indicating that
particulate loadings exceed the set-point. There is no limit on the
duration of time, however, that the bag house may be operating under
these conditions. To ensure that you take both corrective and proactive
measures to minimize the frequency and duration of bag leak detection
system alarms, you must operate and maintain the fabric filter to
ensure that the bag leak detection system alarm does not sound more
than 5 percent of the operating time during a 6-month period.\284\ We
note that the Agency also proposed this requirement for boilers and
process heaters that do not burn hazardous waste. See 68 FR at 1708
(January 13, 2003). If you exceed the alarm set-point more than 5
percent of the time during a 6-month period, you would be required to
notify the delegated regulatory authority within 5 days. In the
notification, you must describe the causes of the excessive exceedances
and the revisions to the design, operation, or maintenance of the
combustor or baghouse you are taking to minimize exceedances. This
notification would alert the regulatory authority of the excessive
exceedances so that they may review and confirm the corrective measures
you are undertaking. See proposed Sec. 63.1206(c)(7)(ii)(C).
---------------------------------------------------------------------------

\284\ Periods of time when the combustor is operating but the
bag leak detection system is malfunctioning must be considered
exceedances of the set-point.
---------------------------------------------------------------------------

We also conclude that the current exemption from the bag leak
detection system requirements for cement kilns should be eliminated. We
did not require bag leak detection systems for cement kilns in the
September 1999 Final Rule because cement kilns are subject to an
opacity standard and must monitor opacity with a continuous monitor. As
a practical matter, however, the opacity levels achieved during the
comprehensive performance test will be lower, often substantially
lower, than the opacity standard. Thus, absent effective operating
parameter limits on the fabric filter based on performance test
operations, we cannot ensure that performance is maintained at the
level achieved during the performance test (and that you remain in
compliance with the particulate matter and other

[[Continued on page 21347]]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]]
[[pp. 21347-21385]] National Emission Standards for Hazardous Air Pollutants:
Proposed Standards for Hazardous Air Pollutants for Hazardous Waste
Combustors (Phase I Final Replacement Standards and Phase II)
[[Continued from page 21346]]

[[Page 21347]]

standards \285\). Consequently, we propose to require that cement kilns
comply with the bag leak detection requirements (as proposed to be
revised) under Sec. 63.1206(c)(7)(ii).\286\ We note that, although
triboelectric detectors are generally used as bag leak detectors given
their ability to detect very low loadings of particulate matter, cement
kilns may use the transmissometers they currently use for opacity
monitoring provided that the transmissometer is sensitive enough to
detect subtle increases in particulate matter loading over normal (not
performance test) loadings.
---------------------------------------------------------------------------

\285\ Because controlling particulate matter also controls
semivolatile and low volatile metals (and dioxin/furan if you use
activated carbon injection), exceeding the particulate matter
loadings achieved during the performance test is also evidence of
failure to ensure compliance with the emission standards for those
pollutants.
\286\ Because the proposed bag leak detection requirements are
more stringent than the opacity standard, exempting cement kilns
from the New Source Performance Standards for particulate matter and
opacity under Sec. 60.60 continues to be appropriate. See
Sec. Sec. 63.1204(h) and 63.1220(h).
---------------------------------------------------------------------------

Finally, we request comment on whether it is practicable to
establish the alarm set-point for the back leak detection system based
on the detector response achieved during the performance test rather
than as recommended in the Agency's guidance document.\287\ The
guidance document recommends that you establish the alarm set-point at
a level that is twice the detector response achieved during bag
cleaning. Although establishing the set-point at this level would avoid
frequent exceedances due to normal bag cleaning, we are concerned that
it may not be low enough to detect gradual degradation in fabric filter
performance that, for example, can be caused by pinholes in the bags.
Moreover, establishing the set-point at a detector response that is
twice the response achieved during bag cleaning may not be low enough
to require you to take corrective measures if particulate matter
loadings increase above the levels achieved during the performance
test, and thus at loadings that may indicate an exceedance of the
particulate matter emission standard. To avoid alarms caused by bag
cleaning cycles, the alarm set-point would be established as the
average detector response of the test run averages during the
particulate matter performance test, and would be established as a 6-
hour rolling average updated each hour with a one-hour block average.
This is the time that could be required to conduct three runs of a
particulate matter performance test. The one-hour block average would
be the average of the detector responses over each 15-minute block.
---------------------------------------------------------------------------

\287\ USEPA, ``Fabric Filter Bag Leak Detection Guidance,''
September 1997.
---------------------------------------------------------------------------

3. What Is the Rationale for Proposing to Revise the Compliance
Requirements for Electrostatic Precipitators and Ionizing Wet Scrubbers?
We propose a two-tiered approach to ensure performance of
electrostatic precipitators and ionizing wet scrubbers: (1) Use of a
particulate matter continuous emissions detector for process monitoring
to signal when you must take corrective measures to address maintenance
or other factors causing relative or absolute mass particulate matter
loadings to be higher than the levels achieved during the performance
test; or (2) use of site-specific operating parameter limits. You could
choose to comply with either tier.
a. How Would Tier I Work? Under Tier I, you would use a particulate
matter continuous emissions detector for process monitoring to signal
when you must take corrective measures to address maintenance or other
factors causing relative or absolute mass particulate matter loadings
to be higher than the levels achieved during the performance test. You
would establish an alarm set-point as the average detector response
achieved during the particulate matter emissions performance test. The
limit would be applied as a 6-hour rolling average updated each hour
with a one-hour block average to correspond to the time it could take
to conduct three runs of a performance test. The one-hour block average
would be the average of the detector responses over each 15-minute block.
If you exceed the alarm set-point, you must immediately take the
corrective measures you specify in your operation and maintenance plan
to bring the response below the set-point. To ensure that you take both
corrective and proactive measures to minimize the frequency and
duration of exceedances, you would be required to operate and maintain
the electrostatic precipitator and ionizing wet scrubber to ensure that
the alarm set-point is not exceeded more than 5 percent of the
operating time during a 6-month period.\288\ This is consistent with
the proposed requirement to limit the period of time that a fabric
filter may be operating under conditions of poor performance. If you
exceed the alarm set-point more than 5 percent of the time during a 6-
month period, you would be required to notify the delegated regulatory.
This notification would alert the regulatory authority of the excessive
exceedances so that they may take corrective measures, such as
requiring you to revise the operation and maintenance plan.
---------------------------------------------------------------------------

\288\ Periods of time when the combustor is operating but the
bag leak detection system is malfunctioning must be considered
exceedances of the set-point.
---------------------------------------------------------------------------

You may use any detector as a particulate matter continuous monitor
provided that the detector response correlates with relative or
absolute particulate matter mass emissions and that it can detect small
changes in particulate matter loadings.\289\ You would include in the
performance test plan a description of the particulate matter detector
you select and information documenting that the detector response
correlates with relative or absolute particulate matter loadings and
that the detector can detect small changes in particulate matter
loadings above the levels anticipated during the comprehensive
performance test. For example, if you anticipate to achieve a
particulate matter emission level of 0.010 gr/dscf during the
comprehensive performance test, your detector should be able to
distinguish between particulate matter loadings of 0.010 gr/dscf and
0.011 gr/dscf.
---------------------------------------------------------------------------

\289\ Please note that, for the purpose of process monitoring
proposed here, you need not correlate the particulate matter
detector to particulate matter emission concentrations.
---------------------------------------------------------------------------

b. How Would Tier II Work? Under Tier II, you would comply with
site-specific operating parameter limits you establish under Sec.
63.1209(m)(1)(iv). As currently required, the operating limits would be
linked to the automatic waste feed cutoff system. Exceedance of an
operating limit would be a violation and is evidence of failure to
ensure compliance with the particulate matter, semivolatile metal, and
low volatile metal emission standards.

IV. Other Proposed Compliance Revisions

A. What Is the Proposed Clarification to the Public Notice Requirement
for Approved Test Plans?

We are proposing in today's notice to add clarifying language to
the section 1207(e)(2) public notification requirement for approved
performance test and CMS performance evaluation test plans. The Agency
believes that adequate public involvement is an essential element to
the continuing and successful management of hazardous waste. Providing
opportunities for timely and adequate public notice is necessary to
fully inform nearby communities of a source's plans to initiate
important waste management

[[Page 21348]]

activities. In 1995, we expanded the RCRA public participation
requirements for hazardous waste combustion sources to require that the
State Director issue a public notice prior to a source conducting a
RCRA trial burn emission test. See 60 FR 63417, 40 CFR 270.62(b)(6) and
40 CFR 270.66(d)(3). The purpose of this notification requirement was
to inform the public of an upcoming trial burn should an individual be
interested in reviewing the results of the test. When we promulgated
the Phase I hazardous waste combustion NESHAP in 1999, we included a
similar requirement in subpart EEE for the same general purpose.
Section 1207(e)(2) of subpart EEE requires that sources issue a public
notice announcing the approval of site-specific performance test plans
and CMS performance evaluation test plans and provide the location
where the plans will be made available to the public for review. We
neglected, however, to include direction regarding how and when sources
should notify the public, what the notification should contain, or
where and for how long the test plans should be made available. As a
result, we are proposing to add clarifying language to the section
1207(e)(2) public notification requirement. We are using the RCRA trial
burn notification requirements as a foundation for the proposed
clarifications.
1. How Should Sources Notify the Public?
The source must make a reasonable effort to provide adequate
notification of the approval of their site-specific performance test
and CMS performance evaluation test plans. Because this notification is
intended for informational purposes only, we are proposing that sources
use their facility/public mailing list. We expect that by the time a
source receives approval of its subpart EEE test plans, a facility/
public mailing list already would have been developed in response to
the source's RCRA and CAA permitting activities. As such, we are
proposing that sources use the facility/public mailing list developed
under 40 CFR 70.7(h)(1), 71.11(d)(3)(i)(E) and 124.10(c)(1)(ix), for
purposes of this notification. Sources may voluntarily choose to use
other mechanisms in addition to a distribution to the facility/public
mailing list, if previous experience has shown that such additional
mechanisms are necessary to reach all interested segments of the
community. For example, sources may consider using press releases,
advertisements, visible signs, and outreach to local community,
professional, and interest groups in addition to the required
distribution to the facility/public mailing list.
2. When Should Sources Notify the Public of Approved Test Plans?
The existing regulations require that sources issue a public notice
after the Administrator has approved the site-specific performance test
and CMS performance evaluation test plans. It is important to remember
that the purpose of this notification is similar to that required under
RCRA for trial burn tests. See 60 FR 63417, 40 CFR 270.62(b)(6) and 40
CFR 270.66(d)(3). The notification is intended to provide information
to the public regarding the upcoming performance test. It is not
intended to solicit comment on the performance test plan. We considered
proposing that the notification occur within 30 days of the source's
receipt of test plan approval. However, we chose not to proceed with
this option because we were concerned that the notification would not
be as meaningful to the public if too much time elapses between the
test plan approval notification and the actual initiation of the
performance test. In order to provide the public with adequate notice
of the upcoming test and a reasonable period of time to review the
approved plans prior to the test, we are proposing that the source
issue its notice after test plan approval, but no later than 60 days
prior to conducting the test. We believe that this also will allow the
source sufficient time to prepare its public notice and corresponds to
the 40 CFR 63.1207(e)(1)(i)(B) requirement for a source to notify the
Administrator of its intention to initiate the test.
3. What Should the Notification Include?
Similar to the public involvement requirements for RCRA trial burn
tests, we are proposing that the notification contain the following
information:
(1) The name and telephone number of the source's contact person;
(2) The name and telephone number of the regulatory agency's
contact person;
(3) The location where the approved performance test and CMS
performance evaluation test plans and any necessary supporting
documentation can be reviewed and copied;
(4) The time period for which the test plans will be available for
public review, and;
(5) An expected time period for commencement and completion of the
performance test and CMS performance evaluation test.
4. Where Should the Plans Be Made Available and for How Long?
The site-specific performance test and CMS performance evaluation
test plans must be made available at an unrestricted location which is
accessible to the public during reasonable hours and provides a means
for the public to obtain copies of the plans if needed. To provide for
adequate time for the public to review the test plans, we are proposing
that the plans be made available for a total of 60 days, beginning on
the date that the source issues its public notice.

B. What Is the Proposed Clarification to the Public Notice Requirement
for the Petition To Waive a Performance Test?

Sources that petition the Administrator for an extension of time to
conduct a performance test (in other words, obtain a performance test
waiver), are required under section 1207(e)(3)(iv) to notify the public
of their petition. Although the regulatory language does provide some
direction regarding how the source may notify the public (e.g., using a
public mailing list), it does not provide any direction regarding when
this notice must be issued or what it must contain. As a result, we are
proposing in today's notice to add clarifying language to the Section
1207(e)(3)(iv) public notice requirement.
1. When Should Sources Notify the Public of a Petition To Waive a
Performance Test?
We are proposing that a source notify the public of a petition to
waive a performance test at the same time that the source submits its
petition to the Administrator. Although not explicitly stated in
section 1207(e)(3)(iv), this was our original intent. In the July 3,
2001, preamble to the subpart EEE proposed technical amendments, we
provided a time line of the waiver petitioning process for an initial
Comprehensive Performance Test.\290\ In that time line, we indicated
that the submittal of the petition and the public notification should
occur at the same time.
---------------------------------------------------------------------------

\290\ It should be noted that the petition for waiver of a
performance test applies to both the initial test and all subsequent
tests. See 40 CFR 1207(e)(3).
---------------------------------------------------------------------------

2. What Should the Notification Include?
The notification of a petition to waive a performance test is an
informational notification. As such, we are proposing that it include
the same level of information as that provided by a source for the
notification of an approved test plan:

[[Page 21349]]

(1) The name and telephone number of the source's contact person;
(2) The name and telephone number of the regulatory agency's
contact person;
(3) The date the source submitted its site-specific performance
test plan and CMS performance evaluation test plans; and
(4) The length of time requested for the waiver.

Part Four: Impacts of the Proposed Rule

I. What Are the Air Impacts?

Table 1 of this preamble shows the emissions reductions achieved by
the proposed rule for all existing hazardous waste combustor sources.
For Phase I sources--incinerators, cement kilns, and lightweight
aggregate kilns--the emission reductions represent the difference in
emissions between sources controlled to the proposed standards and
estimated emissions when complying with the interim MACT standards
promulgated on February 13, 2002. For Phase II sources--industrial/
commercial/institutional boilers and process heaters and hydrochloric
acid production facilities--the reductions represent the difference in
emissions between the proposed standards and the current baseline of
control provided by 40 CFR part 266, subpart H.
Nationwide baseline HAP emissions from hazardous waste combustors
are estimated to be approximately 13,000 tons per year at the current
level of control. Today's proposed standards would reduce emissions of
hazardous air pollutants and particulate matter by approximately 3,300
tons per year.
Nationwide emissions of dioxin/furans from all hazardous waste
combustors will be reduced by 4.7 grams TEQ per year. Emissions of HAP
metals from all hazardous waste combustors will be reduced by 23 tons
per year, including one ton per year of mercury. We estimate that
particulate matter itself, a surrogate for HAP metals will be reduced
by over 1,700 tons per year. Finally, emissions of hydrogen chloride
and chlorine gas from all hazardous waste combustors will reduced by
nearly 1,500 tons and over 100 tons per year, respectfully.\291\ A
discussion of the emission estimates methodology and results is
presented in ``Draft Technical Support Document for HWC MACT
Replacement Standards, Volume V: Emission Estimates and Engineering
Costs'' (Chapter 3) in the docket for today's proposal.
---------------------------------------------------------------------------

\291\ We are, however, proposing to establish alternative risk-
based standards, pursuant to CAA section 112(d)(4), which could be
elected by the source in lieu of the MACT emission standards for
total chlorine. The emission limits would be based on national
exposure standards that ensure protection of public health with an
ample margin of safety. See Part Two, Section XIII for additional
details.If we were to adopt alternative risk-based standards, then
the national annual emissions reductions for total chlorine are overstated.

Table 1.--Nationwide Annual Emissions Reductions of HAPs and Other
Pollutants
------------------------------------------------------------------------
Estimated
emission
Pollutant reductions (tons
per year) \1\
------------------------------------------------------------------------
Dioxin/furans........................................ 0.3
Mercury.............................................. 0.93
Cadmium.............................................. 0.50
Lead................................................. 3.30
Arsenic.............................................. 1.27
Beryllium............................................ 0.31
Chromium............................................. 8.97
Antimony............................................. 1.18
Cobalt............................................... 0.42
Nickel............................................... 1.57
Selenium............................................. 0.28
Manganese............................................ 4.50
Hydrogen Chloride.................................... 1470
Chlorine Gas......................................... 107
Particulate Matter................................... 1727
------------------------------------------------------------------------
\1\ Dioxin/furan emissions reductions and reductions expressed as grams
TEQ.

II. What Are the Water and Solid Waste Impacts?

We estimate that water usage would increase by 4.8 billion gallons
per year if the proposed MACT standards were adopted. In addition to
the increased water usage, an additional 4.6 billion gallons per year
of wastewater would be produced. We estimate the additional solid waste
that would need to be treated as a result of the proposed standards to
be 10,400 tons per year. The costs associated with these hazardous
waste treatment/disposal and water requirements are accounted for in
the national annualized compliance cost estimates. A discussion of the
methodology used to estimate impacts is presented in ``Draft Technical
Support Document for HWC MACT Replacement Standards, Volume V: Emission
Estimates and Engineering Costs' (Chapters 4 and 5) that is available
in the docket.

III. What Are the Energy Impacts?

We estimate an increase of approximately 133 million kilowatt hours
(kWh) in national annual energy usage as a result of the proposed
standards. The increase results from the electricity required to
operate air pollution control devices installed to meet the proposed
standards, such as baghouses and wet scrubbers.

IV. What Are the Control Costs?

Control costs, as presented in this section, refer only to
engineering, operation, and maintenance costs associated with unit/
system upgrades necessary to meet the proposed replacement standards.
These costs do not incorporate any market-based adjustments. All costs
presented in this section are annualized estimates in 2002 dollars.
We estimate there are a total of 276 sources \292\ that may be
subject to requirements of the proposed rule. Liquid and solid fuel
boilers represent approximately 43 percent of this total, followed by
on-site incinerators at 33 percent, and cement and lightweight
aggregate kilns at 12 percent. Commercial incinerators and hydrochloric
acid production furnaces make up the remaining 12 percent of the total.
---------------------------------------------------------------------------

\292\ For purposes of this discussion, a source is defined as
the air pollution control system associated with the hazardous waste
combustion unit(s). A source may contain one or more combustion
units, and a facility may operate one or more sources.
---------------------------------------------------------------------------

Total national engineering costs for the proposed standards are
estimated to range from $57.7 million to $77.9 million per year. The
low end of this range reflects total upgrade costs excluding controls
to meet the total chlorine standard.\293\ All Phase II sources combined
represent about 66 percent or 80 percent of this total, depending upon
section 112(d)(4) scenario. The average cost per source is expected to
be highest for lightweight aggregate kilns and solid fuel boilers,
ranging from $329,000 to $400,000 and $217,000 to $283,000,
respectively. Average liquid fuel boiler costs range from $378,000 to
$419,000 per system. Hydrochloric acid production furnaces were found
to have average system costs of about $200,000 under both section
112(d)(4) scenarios. On-site incinerators and commercial incinerators
were found to generally have the lowest average cost ranges. Average
annualized engineering costs for on-site incinerators are estimated to
range from $16,300 to $139,000 per source, while average annual per
source engineering costs for commercial incinerators are estimated to
range from $67,000 to $247,000. For all Phase I sources (140 sources;
commercial incinerators, on-site incinerators, cement kilns, and

[[Page 21350]]

lightweight aggregate kilns), average annualized engineering costs are
estimated to range from $76,000 to $184,000 per source. The combined
Phase II sources (136 sources; solid and liquid fuel-fired boilers and
hydrochloric acid production furnaces) had average annualized
engineering costs ranging from $341,000 to $380,000 per source. Across
all sectors covered by today's proposal (Phase I and Phase II sources),
average annualized costs were found to range from $209,000 to $282,000
per source.
---------------------------------------------------------------------------

\293\ We are proposing using section 112(d)(4) of the Clean Air
Act to establish risk-based standards for total chlorine for
hazardous waste combustors (except for hydrochloric acid production
furnaces). The low-end of this cost range assumes all facilities
emit total chlorine levels below risk-based levels of concern. Under
this scenario, no total chlorine controls are assumed to necessary.
---------------------------------------------------------------------------

Engineering compliance (control) costs have also been assessed on a
per ton of waste burned basis. Captive energy recovery sources
(includes solid and liquid fuel-fired boilers, and hydrochloric acid
production furnaces), burning a total of 1,001,500 tons of hazardous
waste per year, are projected to experience the highest average
incremental costs, ranging from $46 to $52 per ton. Commercial energy
recovery sources (cement kilns and LWAKs), burning approximately
1,093,800 tons per year, may see incremental control costs ranging from
$7.50 to $8.50 per ton. Captive (on-site) and commercial incinerators
burn an estimated 1,010,600 tons and 452,200 tons per year,
respectively. These sources are estimated to experience average
incremental engineering costs ranging from $1.50 to $12.70 per ton for
captive and $2.20 to $8.20 per ton for commercial sources.
The aggregate control costs presented in this section do not
reflect the anticipated real world cost burden on the economy. Any
market disruption, such as the implementation of hazardous waste MACT
or risk-based standards will cause a short-tem disequilibrium in the
hazardous waste burning market. Following the implementation of the
replacement standards, market adjustments will occur in a natural
economic process designed to reach a new market equilibrium. Actual
cost impacts to society are more accurately measured by taking into
account market adjustments. These costs are commonly termed Social
Costs, and are generally less than total engineering costs due to cost
efficiencies implemented during the market adjustment process. Social
Costs theoretically represent the total real world costs of all goods
and services society must give up in order to gain the added protection
to human health and the environment. Social Costs are presented in Part
VIII of this Section.

V. Can We Achieve the Goals of the Proposed Rule in a Less Costly Manner?

Section 1(b)(3) of Executive Order 12866 instructs Executive Branch
Agencies to consider and assess available alternatives to direct
regulation prior to making a determination for regulation. This
regulatory determination assessment should be considered, ``to the
extent permitted by law, and where applicable.'' The ultimate purpose
of the regulatory determination assessment is to ensure that the most
efficient tool, regulation, or other type of action is applied in
meeting the targeted objective(s). Requirements for MACT standards
under the Clean Air Act, as mandated by Congress, have compelled us to
select today's regulatory approach. Furthermore, we are under legal
obligation to meet the targeted objectives of today's proposal through
a regulatory action. As a result, alternatives to direct regulatory
action were not evaluated.
In addition to the statutory and legal mandates necessitating
today's proposed rulemaking, we believe that federal regulation is the
most efficient approach for helping to correct market failures leading
to the negative environmental externalities resulting from the
combustion of hazardous waste. The complex nature of the pollutants,
waste feeds, waste generators, and the diverse nature of the combustion
market would limit the effectiveness of a non-regulatory approach such
as taxes, fees, or an educational-outreach program.
The hazardous waste combustion industry operates in a dynamic
market. Several combustion facilities and systems have closed or
consolidated over the past several years and this trend is likely to
continue. These closures and consolidations may lead to reduced air
pollution, in the aggregate, from hazardous waste facilities. However,
the ongoing demand for hazardous waste combustion services will
ultimately result in a steady equilibrium as the market adjusts over
the long-term. We therefore expect that air pollution problems from
these facilities, and the corresponding threats to human health and
ecological receptors, will continue if a regulatory action was not
implemented.
We believe that the market has generally failed to correct the air
pollution problems resulting from the combustion of hazardous wastes
for several reasons. First, there exists no natural market incentive
for hazardous waste combustion facilities to incur additional costs
implementing control measures. This occurs because the individuals and
entities who bear the negative human health and ecological impacts
associated with these actions have no direct control over waste burning
decisions. This environmental externality occurs because the private
industry costs of combustion do not fully reflect the human health and
environmental costs of hazardous waste combustion. Second, the parties
injured by the combusted pollutants are not likely to have the
resources or technological expertise to seek compensation from the
damaging entity (combustion source) through legal or other means.\294\
Finally, emissions from hazardous waste combustion facilities directly
affect a ``public good,'' the air. Improved air quality benefits human
health and the environment. The absence of government intervention,
therefore, will perpetuate a market that fails to fully internalize key
negative externalities, resulting in a sub-optimal quantity and quality
of public goods, such as air.
---------------------------------------------------------------------------

\294\ Some economists consider this a failure of full and proper
enforcement of property rights.
---------------------------------------------------------------------------

We have assessed several regulatory options designed to mitigate
the unacceptable levels of risk to human health and the environment
resulting from the combustion of hazardous waste in the targeted units.
We believe, based on available data, that our preferred regulatory
approach,\295\ as presented in today's proposed rule, is the most cost-
efficient method for reducing the level of several hazardous air
pollutants. These include: dioxin and furan, mercury, semivolatile and
low volatile metals, and total chlorine emissions (i.e., hydrogen
chloride and chlorine). Carbon monoxide, hydrocarbons, and particulate
matter will also be reduced.
---------------------------------------------------------------------------

\295\ Including our proposal to apply section 112(d)(4) to
establish risk-based standards for total chlorine for all sources,
except hydrochloric acid production furnaces.
---------------------------------------------------------------------------

We evaluated seven alternative methodologies in the development of
today's proposed approach. These were: system removal efficiency plus
feed control, straight emission-based, modified emission-based,
exclusive technology approach, simultaneous achievability, using the
CAA section 112(d)(4) to establish risk-based standards for total
chlorine, and beyond-the-floor. Numerous different combinations of
these methodologies were assessed. Selection of the Agency preferred
approach was based, in part on methodological clarity, implementation
simplicity, cost and economic impacts, stakeholder input, and necessary
protectiveness to human health and the environment.

[[Page 21351]]

VI. What Are the Economic Impacts?

Various market adjustments (i.e., economic impacts) are expected in
response to the changes in hazardous waste combustion costs anticipated
as a result of the replacement standards, as proposed. Economic impacts
may be measured through several factors. This section presents
estimated economic impacts relative to market exits, waste
reallocations, and employment impacts. Economic impacts presented in
this section are distinct from social costs, which correspond only to
the estimated monetary value of market disturbances.

A. Market Exit Estimates

The hazardous waste combustion industry operates in a dynamic
market, with systems entering and exiting the market on a routine
basis. Our analysis defines ``market exit'' as ceasing to burn
hazardous waste. We have projected post-rule hazardous waste combustion
system market exits based on economic feasibility only. Market exit
estimates are derived from a breakeven analysis designed to determine
system viability. This analysis is subject to several assumptions,
including: engineering cost data on the baseline costs of waste
burning, cost estimates for pollution control devices, prices for
combustion services, and assumptions about the waste quantities burned
at these facilities. It is important to note that, for most sectors,
exiting the hazardous waste combustion market is not equivalent to
closing a plant. (Actual plant closure would only be expected in the
case of an exit from the hazardous waste combustion market of a
commercial incinerator closing all its systems.)
Under the Agency's proposed approach, we estimate there may be
anywhere from 51 to 58 systems (sources) that stop burning hazardous
waste. This represents anywhere from 18 percent to 21 percent of the
total number of systems affected by the rule. The range is based on the
inclusion or exclusion of total chlorine controls.\296\ At the high-end
of this range, onsite incinerators represent about 55 percent of the
total number of market exits. Liquid and solid fuel boilers (includes
process heaters) account for 41 percent, and commercial incinerators
account for the remaining. No cement kilns, lightweight aggregate
kilns, or hydrochloric acid production furnaces are projected to exit
the market as a result of the rule. Market exits are estimated to
change only slightly under the alternative regulatory options.
---------------------------------------------------------------------------

\296\ Even though we are proposing to allow sources (except
hydrochloric acid production furnaces) to invoke section 112(d)(4)
in lieu of MACT chlorine control requirements, we have not attempted
to estimate the following: (1) The total number of sources that may
elect to implement this provision, and, (2) what level of control
may be necessary following a section 112(d)(4) risk-based
determination, since this would vary on a site-by-site basis.
---------------------------------------------------------------------------

B. Quantity of Waste Reallocated

Some combustion systems (sources) may no longer be able to cover
their hazardous waste burning costs as a result of rule requirements,
as proposed. These sources are expected to divert or reroute their
wastes to alternative burners.\297\ For multiple system facilities,
this diversion may include on-site (non-commercial) waste consolidation
among fewer systems at the same facility. A certain portion of this
waste may also be reallocated to waste management alternatives (e.g.,
solvent reclamation). Combustion, however, is likely to remain the
lowest cost option. Thus, we expect that the vast majority of
reallocated waste will continue to be managed at combustion facilities.
---------------------------------------------------------------------------

\297\ This analysis includes the cost of waste transport to
alternative combustion sources, burning fees, and purchase of
alternative fuels (if appropriate).
---------------------------------------------------------------------------

Our economic model indicates that, in response to today's rule,
approximately 87,500 to 120,900 tons of hazardous waste may be
reallocated, representing up to 3.4 percent of the total 1999 estimated
quantity of hazardous waste burned at all sources. This estimate
includes on-site consolidations and off-site diversions. Off-site
diversions alone represent no more than 1.5 percent of the total waste
burned. About 56 percent to 65 percent of the total reallocated waste
quantity is expected to be consolidated among fewer systems at the same
non-commercial facility. Commercial incinerators and commercial energy
recovery (cement kilns and lightweight aggregate kilns) facilities are
projected to receive all hazardous waste that is rerouted off-site.
Onsite incinerators and boilers are the primary source of all off-site
diverted waste. Based on the high estimate for total waste reallocated
(120,900 tons), commercial incinerators and cement kilns are projected
to receive 37 percent and 7 percent, respectively. The remainder, as
mentioned above, is projected to be consolidated on-site. Currently,
there is more than adequate capacity to accommodate all off-site waste
diversions.

C. Employment Impacts

Today's rule is likely to cause employment shifts across all of the
hazardous waste combustion sectors. These shifts may occur as specific
combustion facilities find it no longer economically feasible to keep
all of their systems running, or to stay in the hazardous waste market
at all. When this occurs, workers at these locations may lose their
jobs or experience forced relocations. At the same time, the rule may
result in employment gains, as new purchases of pollution control
equipment stimulate additional hiring in the pollution control
manufacturing sector, and as additional staff are required at selected
combustion facilities to accommodate reallocated waste and/or various
compliance activities.
1. Employment Impacts--Dislocations (losses)
Primary employment dislocations (losses) in the combustion industry
are likely to occur when combustion systems consolidate the waste they
are burning into fewer systems or when a facility exits the hazardous
waste combustion market altogether. Operation and maintenance labor
hours are expected to be reduced for each system that stops burning
hazardous waste. For each facility that completely exits the market,
employment losses will likely also include supervisory and
administrative labor.
Total incremental employment dislocations potentially resulting
from the proposed replacement standards are estimated to range from 308
to 387 full-time-equivalent (FTE) jobs. Depending upon the scenario,
on-site incinerators and boilers are responsible for anywhere from
about 85 to 100 percent all potential job dislocations. Their
significant share of the losses is a function of both the large number
of systems affected, and the number of expected exits within these sectors.
2. Employment Impacts--Gains
In addition to employment dislocations, today's rule is also
expected to result in job gains. These gains are projected to occur to
both the air pollution control industry and to combustion firms as they
hire personnel to accommodate reallocated waste and/or comply with the
various requirements of the rule. Hazardous waste combustion sources
are projected to need additional operation and maintenance personnel
for the new pollution control equipment and other compliance
activities, such as new reporting and record keeping requirements.
The total annual employment gains associated with the proposed
standards are estimated to range from 407 to 525 FTEs. Job gains to the
air pollution

[[Page 21352]]

control industry \298\ represent about 31 percent of this total. Among
all combustors, boilers are projected to experience the greatest number
of job gains, followed by cement and lightweight aggregate kilns. Job
gains in these sectors alone represent about 55 percent to 61 percent
of total projected gains, depending upon regulatory scenario.
---------------------------------------------------------------------------

\298\ Manufacturers and distributers of air pollution control
devices are expected to increase sales as a result of this action.
---------------------------------------------------------------------------

While it may appear that this analysis suggests overall net job
creation, such a conclusion would be inappropriate. Because the gains
and losses occur in different sectors of the economy, they should not
be added together. Doing so would mask important distributional effects
of the rule. In addition, the employment gain estimates reflect within
sector impacts only and therefore do not account for potential job
displacement across sectors. This may occur if investment funds are
diverted from other areas of the larger economy.

VII. What Are the Benefits of Reductions in Particulate Matter Emissions?

For the 1999 rule, we estimated the avoided incidence of mortality
and morbidity associated with reductions in particulate matter (PM)
emissions.\299\ Estimates of cases of mortality and morbidity avoided
were made for children and the elderly, as well as the general
population, using concentration-response functions derived from human
epidemiological studies. Morbidity effects included respiratory and
cardiovascular illnesses requiring hospitalization, as well as other
illnesses not requiring hospitalization, such as acute and chronic
bronchitis and acute upper and lower respiratory symptoms. Decreases in
particulate matter-related minor restricted activity days (MRADs) and
work loss days (WLDs) were also estimated. Rates of avoided incidence,
work days lost, and days of restricted activity were estimated for each
of 16 sectors surrounding a facility using the concentration-response
functions and sector-specific estimates of the corresponding population
and model-derived ambient air concentration, either annual mean
PM10 or PM2.5 concentrations or distributions of
daily PM10 or PM2.5 concentrations, depending on
the concentration-response function. The sectors were defined by 4
concentric rings out to a distance of 20 kilometers (about 12 miles),
each of which was divided into 4 quadrants. The sector-specific rates
were weighted by facility-specific sampling weights and then summed to
give the total incidence rates for a given source category.\300\
---------------------------------------------------------------------------

\299\ See ``Human Health and Ecological Risk Assessment Support
to the Development of Technical Standards for Emissions from
Combustion Units Burning Hazardous Wastes: Background Document,'' July 1999.
\300\ It should be noted that the avoided incidence estimates
were based entirely on the incremental decrease in ambient air
concentrations associated with emission controls on the hazardous
waste sources subject to the 1999 rule. Background levels of
particulate matter were assumed to be sufficiently high to exceed
any possible threshold of effect but ambient background levels of
particulate matter were not otherwise considered in the analysis.
---------------------------------------------------------------------------

Since performing the risk assessment for the 1999 Assessment, the
Agency has updated its benefits methodology to reflect recent advances
in air quality modeling and human health benefits modeling. To estimate
PM exposure for the 1999 risk assessment, the Agency used the
Industrial Source Complex Model-Short Term Version 3 (ISCST3). More
recent EPA benefits analyses have used more advanced air-quality
models. For example, the Agency's assessment of the industrial boilers
and process heaters NESHAP used the Climatological Regional Dispersion
Model (CRDM), which uses a national source-receptor matrix to estimate
exposure associated with PM emissions.\301\ Similarly, the Agency's
analysis of the proposed Inter-state Air Quality Rule used the Regional
Modeling System for Aerosols and Deposition (REMSAD), which also
accounts for the long-range transport of particles.\302\ In contrast,
ISCST3 modeled exposure within a 20-kilometer radius of each emissions
source for the 1999 risk assessment.\303\ To the extent that PM is
transported further than 20 km from each emissions source, the 1999
risk assessment may underestimate PM exposure. In addition, to estimate
exposure in the 1999 risk assessment, EPA used block-group-level data
from the 1990 Census. More recent studies use data from the 2000 Census.
---------------------------------------------------------------------------

\301\ U.S. EPA, Regulatory Impact Analysis of The Final
Industrial Boilers and Process Heaters NESHAP: Final Report, February 2004.
\302\ U.S. EPA, Benefits of the Proposed Inter-State Air Quality
Rule, January 2004.
\303\ Research Triangle Institute, Human Health and Ecological
Risk Assessment Support to The Development of Technical Standards
for Emissions from Combustion Units Burning Hazardous Wastes:
Background Document, prepared for U.S. EPA, Office of Solid Waste, July 1999.
---------------------------------------------------------------------------

More recent EPA benefits analyses also apply a different
concentration-response function for PM mortality than that used for the
1999 risk assessment. In 1999, EPA used the concentration-response
function published by Pope, et al. in 1995.\304\ Since that time,
health scientists have refined estimates of the concentration-response
relationship, and EPA has updated its methodology for estimating
benefits to reflect these more recent estimates. In the regulatory
impact analysis of the non-hazardous boiler MACT standards, EPA used
the Krewski, et al. re-analysis of the 1995 Pope study to estimate
avoided premature mortality.\305\ Since the relative risk estimated in
the Krewski study (1.18) is nearly the same as that presented in Pope
et al. (1.17), the Agency assumes that updating the 1999 risk
assessment to reflect the results of the 2000 Krewski study would have
minimal impact on the estimated benefits associated with the proposed
HWC MACT replacement standards.
---------------------------------------------------------------------------

\304\ Pope, C.A., III, M.J. Thun, M.M. Namboodiri, D.W. Dockery,
J.S. Evans, F.E. Speizer, and C.W. Heath, Jr. 1995. Particulate air
pollution as a predictor of mortality in a prospective study of U.S.
adults. American Journal of Respiratory and Critical Care
Medicine151:669-674, as cited in Research Triangle Institute, op. cit.
\305\ Krewski D, Burnett RT, Goldbert MS, Hoover K, Siemiatycki
J, Jerrett M, Abrahamowicz M, White WH. 2000. Reanalysis of the
Harvard Six Cities Study and the American Cancer Society Study of
Particulate Air Pollution and Mortality. Special Report to the
Health Effects Institute, Cambridge, MA, July 2000.
---------------------------------------------------------------------------

For the current proposal, we took the avoided incidence estimates
from the September 1999 final rule and adjusted them to reflect the
particulate matter emission reductions projected to occur under the
proposed standards and the reduction in the numbers of facilities
burning hazardous wastes since the analysis for the final rule was
completed. For cement kilns, lightweight aggregate kilns, and
incinerators, the estimates were made by adjusting the respective
estimates at the source category level by the ratio of emission
reductions (for today's proposed rule vs. the 1999 final rule) and the
ratio of the number of facilities affected by the rules (facilities
currently burning hazardous wastes vs. facilities burning hazardous
wastes in the analysis for the September 1999 final rule).\306\ For
liquid and solid fuel-fired boilers and hydrochloric acid production
furnaces, we extrapolated the avoided incidence from the incinerator
source category using a similar approach except that the ratios of the
exposed populations were used (corresponding to the concentration-

[[Page 21353]]

response functions from the 1999 analysis), instead of the number of
facilities. We estimated the exposed populations for hazardous waste-
burning boilers and hydrochloric acid production furnaces using the
same GIS methods as the September 1999 final rule (i.e., a 16 sector
overlay). Nonetheless, the extrapolated estimates are subject to some
uncertainty. The estimates of avoided incidence of mortality and
morbidity are shown in Table 2. The estimates of days of restricted
activity and days of work lost are shown in Table 3.
---------------------------------------------------------------------------

\306\ To account for the increase in population since the 1990
census was taken, for the Phase I sources we also adjusted the
avoided incidence estimates by the ratio of the population at the
national level (corresponding to the concentration-response
function) for the year 2000 census vs. the 1990 census. For Phase II
source, we used the year 2000 census to develop source category-
specific population estimates for use in the extrapolations.

Table 2.--PM-Related Avoided Incidence of Mortality and Morbidity
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hospital admissions Respiratory Illnesses
---------------------------------------------------------------------------------------------------------------
Source category Respiratory Chronic Acute Lower Upper
Mortality illness Cardiovascular bronchitis bronchitis respiratory respiratory
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cement Kilns............................ 0.0 0.0 0.0 0.0 0.0 0.1 0.0
Lightweight Aggregate Kilns............. 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Incinerators............................ 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Solid Fuel Boilers...................... 0.0 0.0 0.0 0.1 0.1 0.7 0.1
HCl Production Furnaces................. 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Liquid Fuel Boilers..................... 0.3 0.9 0.4 5.5 4.2 37.2 4.3
Total............................... 0.3 0.9 0.4 5.6 4.3 38.0 4.4
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table 3.--PM-Related Restricted Activity and Work Loss Days
----------------------------------------------------------------------------------------------------------------
Minor Restricted
Source category restricted activity days Work loss days
----------------------------------------------------------------------------------------------------------------
Cement Kilns................................................. 3.1 1.0 0.4
Lightweight Aggregate Kilns.................................. 0.0 0.0 0.0
Incinerators................................................. 0.0 0.0 0.0
Solid Fuel-Fired Boilers..................................... 59.0 19.4 7.1
HCl Production Furnaces...................................... 0.0 0.0 0.0
Liquid Fuel-Fired Boilers.................................... 3692.2 1215.9 443.2
------------------
Total.................................................... 3754.4 1236.4 450.7
----------------------------------------------------------------------------------------------------------------

We also conducted an analysis of key factors that influence the PM-
related health benefits by statistically comparing attributes of the
sources subject to today's proposed rule versus the sources subject to
the 1999 rule. The greater the similarities between the sources covered
by today's proposal and the sources subject to the 1999 rule, the more
confidence we have in the extrapolated incidence estimates. The more
the dissimilarities, the greater is the uncertainty in the estimates.
The comparative analysis is discussed in a separate background document
for today's rule.\307\
---------------------------------------------------------------------------

\307\ See ``Inferential Risk Analysis in Support of Standards
for Emissions of Hazardous Air Pollutants from Hazardous Waste
Combustors,'' prepared under contract to EPA by Research Triangle
Institute, Research Triangle Park, NC.
---------------------------------------------------------------------------

VIII. What are the Social Costs and Benefits of the Proposed Rule?

The value of any regulatory action is traditionally measured by the
net change in social welfare that it generates. Our economic assessment
for today's rule evaluates compliance costs, social costs, benefits,
economic impacts, selected other impacts (e.g., children's health,
unfunded mandates), and small entity impacts. To conduct this analysis,
we examined the current combustion market and practices, developed and
implemented a methodology for examining compliance and social costs,
applied an economic model to analyze industry economic impacts (results
discussed above), examined benefits, and followed appropriate
guidelines and procedures for examining equity considerations,
children's health, and other impacts. The data we used in this analysis
were the most recently available at the time of the analysis. Because
our data were limited, the findings from these analyses are more
accurately viewed as national estimates.

A. Combustion Market Overview

The hazardous waste industry consists of three key segments:
hazardous waste generators, fuel blenders/intermediaries, and hazardous
waste burners. Hazardous waste is combusted at four main types of
facilities: commercial incinerators, on-site incinerators, waste
burning kilns (cement kilns and lightweight aggregate kilns), and
industrial boilers. Commercial incinerators are generally larger in
size and designed to manage virtually all types of solids, as well as
liquid wastes. On-site incinerators are more often designed as liquid-
injection systems that handle liquids and pumpable solids. Waste
burning kilns and boilers generally burn hazardous wastes to generate
heat and power for their manufacturing processes.
As discussed above, we have identified a total of 276 sources
(systems) permitted to burn hazardous waste in the United States.
Liquid fuel-fired boilers account for 107 sources, followed by on-site
incinerators at 92 sources. Cement kilns, hydrochloric acid production
furnaces, and commercial incinerators account for 26, 17, and 15
sources, respectively. Solid fuel-fired boilers and lightweight
aggregate kilns make up the remaining, at 12 and seven systems,
respectively. These 276 sources are operated by a total of 150
different facilities. On-site incinerators account for 69 facilities,
or 46 percent of this total, followed by all boiler facilities at 45
percent (67 facilities). There are 14 cement kilns, 10 commercial
incineration facilities and three lightweight aggregate kilns. A single
facility may have one or more combustion systems. Facilities with
multiple systems may have the same or different types. Thus, the
numbers presented above will not sum to 150 facilities.

[[Page 21354]]

The number of sources per facility in the combustion universe
ranges from one to 12. On average, boilers, hydrochloric acid
production furnaces, and lightweight aggregate kilns, with an average
of 2.0 sources per facility, contain more waste burning combustion
systems per facility than do incinerators and cement kilns, with an
average of 1.4 sources per facility. On-site incinerators, with 1.3
sources per facility, have the lowest average among all types of
combustion devices in the universe.
Combustion systems operating at chemical and allied product
facilities represent 72 percent (199 sources) of the total number of
hazardous waste burning systems. Stone, clay, and glass production
accounts for 12 percent (34 sources), followed by electric, gas, and
sanitation services at 8 percent (22 sources).
The EPA Biennial Reporting System (BRS) reports a total demand for
all combusted hazardous waste, across all facilities, at 3.56 million
tons (U.S. ton) in 1999. Commercial energy recovery (cement kilns and
lightweight aggregate kilns) burned about 31 percent of this total,
followed by on-site incinerators at just over 28 percent, captive
energy recovery (all boilers) at 28 percent, and commercial
incineration at nearly 13 percent. About 62 percent of all waste burned
in 1999 was organic liquids. This is followed by inorganic liquids (15
percent), sludges (13 percent), and solids (9 percent). Hazardous gases
represent about 0.1 percent of the total annual quantity burned. In
terms of waste source, the industrial organic chemicals sector
generates approximately a third of all hazardous waste burned, followed
by pesticides and agricultural chemicals, business services, organic
fibers, medicinal chemicals, pharmaceuticals, plastics materials and
resins, petroleum, and miscellaneous.
Companies that generate large quantities of uniform hazardous
wastes generally find it more economical and efficient to combust these
wastes on-site using their own noncommercial systems. Commercial
incineration facilities manage a wide range of waste streams generated
in small to medium quantities by diverse industries. Cement kilns,
lightweight aggregate kilns, and boilers derive heat and energy by
combining clean burning (solvents and organics) high-Btu liquid
hazardous wastes \308\ with conventional fuels.
---------------------------------------------------------------------------

\308\ Many cement kilns are also able to burn a certain level of
solid waste.
---------------------------------------------------------------------------

Regulatory requirements, liability concerns, and economics
influence the demand for combustion services. Regulatory forces
influence the demand for combustion by mandating certain hazardous
waste treatment standards (land disposal restriction requirements,
etc.). Liability concerns of waste generators affect combustion demand
because combustion, by destroying organic wastes, greatly reduces the
risk of future environmental problems. Finally, if alternative waste
management options are more expensive, hazardous waste generators will
likely choose to send their wastes to combustion facilities in order to
increase their overall profitability.
Throughout much of the 1980s, hazardous waste combustors enjoyed a
strong competitive position and generally maintained a high level of
profitability. During this period, EPA regulations requiring combustion
greatly expanded the waste tonnage for this market. In addition,
federal permitting requirements, as well as powerful local opposition
to siting of new incinerators, constrained the entry of new combustion
systems. As a result, combustion prices rose steadily, ultimately
reaching record levels in 1987. The high profits of the late 1980s
induced many firms to enter the market, in spite of the difficulties
and delays anticipated in the permitting and siting process. Hazardous
waste markets have changed significantly since the late 1980s. In the
early 1990s, substantial overcapacity resulted in fierce competition,
declining prices, poor financial performance, numerous project
cancellations, system consolidations, and facility closures. Since the
mid 1990s, several additional combustion facilities have closed, while
many of those that have remained open have consolidated, or further
consolidated their operations. Available excess capacity is currently
estimated at about 20 percent of the total 1999 quantity combusted.

B. Baseline Specification

Proper and consistent baseline specification is vital to the
accurate assessment of incremental costs, benefits, and other economic
impacts associated with today's proposed rule. The baseline essentially
describes the world absent the proposed rule. The incremental impacts
of today's rule are evaluated by predicting post MACT compliance
responses with respect to the baseline. The baseline, as applied in
this analysis, is the point at which today's rule is promulgated. Thus,
incremental cost and economic impacts are projected beyond the
standards established in the February 13, 2002, Interim Standards Final Rule.

C. Analytical Methodology and Findings--Social Cost Analysis

Total social costs include the value of resources used to comply
with the standards by the private sector, the value of resources used
to administer the regulation by the government, and the value of output
lost due to shifts of resources away from the current market
equilibrium. To evaluate these shifts in resources and changes in
output requires predicting changes in behavior by all affected parties
in response to the regulation, including responses of directly-affected
entities, as well as indirectly-affected private parties.
For this analysis, social costs are grouped into two categories:
economic welfare (changes in consumer and producer surplus), and
government administrative costs. The economic welfare analysis
conducted for today's rule uses a simplified partial equilibrium
approach to estimate social costs. In this analysis, changes in
economic welfare are measured by summing the changes in consumer and
producer surplus. This simplified approach bounds potential economic
welfare losses associated with the rule by considering two scenarios:
compliance costs assuming no market adjustments, and market adjusted
compliance costs. The private sector compliance costs of $57.7 million
to $77.9 million per year, as presented in Section IV, assume no market
adjustments. These costs may be considered to represent the high-end of
total social costs. Our best estimate of social costs assume rational
market adjustments. Under this scenario, increased compliance costs are
examined in the context of likely incentives combustion facilities
would have to continue burning hazardous wastes, and the competitive
balance in different combustion sectors.
For all sectors to meet the proposed replacement standards, total
annualized market-adjusted costs are estimated to range from $41 to $50
million. The low end of this range assumes no chlorine control
costs.\309\ The Phase II sources represent about 83 percent of the
high-end total. Our economic model indicates that two sectors as a
whole, commercial incinerators and cement kilns, would experience net
gains following all market adjustments. This occurs due to marginally
higher prices,

[[Page 21355]]

increased waste receipts, and relatively low upgrade costs. Total
annual government costs are approximately one-half million dollars for
the proposed approach.
---------------------------------------------------------------------------

\309\ We are proposing using section 112(d)(4) of the Clean Air
Act to establish risk-based standards for total chlorine for
hazardous waste combustors (except for hydrochloric acid production
furnaces). The low-end of this cost range assumes all facilities
emit total chlorine levels below risk-based levels of concern. Under
this scenario, no total chlorine controls are assumed to be necessary.
---------------------------------------------------------------------------

D. Analytical Methodology and Findings--Benefits Assessment

This section discusses the monetized and non-monetized benefits to
human health and the environment potentially associated with today's
rule. Monetized human health benefits are derived from reductions in PM
and dioxin/furan exposure and are based on a Value of Statistical Life
(VSL) estimate of $5.5 million.\10\ Monetized environmental benefits
are estimated from visibility improvements expected in response to
reduced air pollution. Non-monetized benefits are associated with human
health, ecological, and waste minimization factors.
---------------------------------------------------------------------------

\310\ Office of Management and Budget. Circular A-4. September 17, 2003.
---------------------------------------------------------------------------

1. Monetized Benefits
Particulate Matter--We developed monetized estimates of human
health benefits associated with reduced emissions of particulate matter
(PM). We also estimated the value of improved visibility associated
with reduced PM emissions.
Results from our risk assessment extrapolation procedure, as
discussed under Section VII above, are used to evaluate incremental
human health benefits potentially associated with particulate matter
emission reductions at hazardous waste combustion facilities. This
analysis used avoided cost factors from the July 1999 Assessment
document, combined with the updated estimates of avoided adverse health
effects related only to particulate matter emissions.
Under the Agency preferred approach, reduced PM emissions are
estimated to result in monetized human health benefits of approximately
$4.18 million per year. This is an undiscounted figure. Avoided PM
morbidity cases account for $2.34 million of this total and include:
respiratory illness, cardiovascular disease, chronic bronchitis, work
loss days, and minor restricted activity. Chronic bronchitis accounts
for approximately 90 percent of the total morbidity cases. All
morbidity cases are assumed to be avoided within the first year
following reduced PM emissions and are not discounted under any scenario.
Avoided premature deaths (mortality) account for the remaining
$1.84 million per year. Assuming a discount rate of three and seven
percent, PM mortality benefits would be $1.70 million and $1.54
million, respectively. Our discounted analysis of PM mortality benefits
assumes that 25 percent of premature mortalities occur during the first
year, 25 percent occur during the second year, and 16.7 percent occur
in each of the three subsequent years after exposure. This methodology
is consistent with the Agency's analysis of the proposed Clear Skies
Act of 2003. Total monetized PM benefits, therefore, are estimated to
range from $4.24 million/year to $4.52 million per year. These findings
appear to indicate that particulate matter reductions from the interim
baseline to the replacement standards are small relative to the
reductions achieved in going to the interim standards. This assessment
does not consider corresponding health benefits associated with the
reduction of metals carried by the PM.
Dioxin/furan--Dioxin/furan emissions are projected to be reduced by
a total of 4.68 grams per year under the Agency Preferred Approach. Of
this total, 0.42 grams/year are derived in going from the interim
standards baseline to the floor levels. The remaining 4.26 grams/year
are derived by going from the floor to beyond-the-floor (BTF)
standards. In the July 23, 1999 Addendum to the Assessment, cancer risk
reductions linked to consumption of dioxin-contaminated agricultural
products accounted for the vast majority of the 0.36 cancer cases per
year that were expected to be avoided due to the 1999 standards. Cancer
risk reductions associated with the replacement standards are expected
to be less than 0.36 cases per year, but greater than zero.
Assuming that the proportional relationship between dioxin/furans
emissions and premature cancer deaths is constant, we estimate that
approximately 0.058 premature cancer deaths will be avoided on an
annual basis under the Agency Preferred Approach because of reduced
dioxin/furans emissions. This estimate reflects a cancer risk slope
factor of 1.56 x 10⁵ [mg/kg/day]^-1. This cancer
slope factor is derived from the Agency's 1985 health assessment
document for polychlorinated dibenzo-p-dioxins \311\ and represents an
upper bound 95th percentile confidence limit of the excess cancer risk
from a lifetime exposure.
---------------------------------------------------------------------------

\311\ USEPA, 1985. Health Assessment Document for
Polychlorinated Dibenzo-p-Dioxins. EPA/600/8-84/014F. Final Report.
Office of Health and Environmental Assessment. Washington, DC.
September, 1985.
---------------------------------------------------------------------------

For the past 12 years the Agency has been conducting a reassessment
of the human health risks associated with dioxin and dioxin-like
compounds. This reassessment \312\ will soon be under review at the
National Academy of Sciences (NAS), as specified by Congress in the
Conference Report accompanying EPA's fiscal year 2003 appropriation
(Title IV of Division K of the Conference Report for the Consolidated
Appropriations Resolution of 2003). Evidence compiled from this draft
reassessment indicates that the carcinogenic effects of dioxin/furans
may be six times as great as believed in 1985, reflecting an upper
bound cancer risk slope factor of 1 x 106 [mg/kg/day]^-1 for
some individuals. Agency scientists' more likely (central tendency)
estimates (derived from the ED01 rather than the
LED01) result in slope factors and risk estimates that are
within 2-3 times of the upper bound estimates (i.e., between 3 x
10⁵ [mg/kg/day]^-1 and 5 x 10⁵ [mg/kg/
day]^-1) based on the available epidemiological and animal
cancer data. Risks could be as low as zero for some individuals. Use of
the alternative upper bound cancer risk slope factor would result in up
to 0.35 premature cancer deaths avoided in response to the proposed
replacement standards for dioxin/furans. The assessment of upper bound
cancer risk using this alternative slope factor should not be
considered Agency policy. The proposed standards for dioxin in today's
rule were not based on this draft reassessment.
---------------------------------------------------------------------------

\312\ U.S.EPA, Exposure and Human Health Reassessment of
2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) and Related Compounds,
September 2000. Note: Toxicity risk factors presented in this
document should not be considered EPA's official estimate of dioxin
toxicity, but rather reflect EPA's ongoing effort to reevaluate
dioxin toxicity.
---------------------------------------------------------------------------

Total non-discounted human health benefits associated with
projected dioxin reductions are estimated at $0.32 million/year. Total
benefits are estimated to range from $0.12 million/year to $0.17
million/year at a 3 percent discount rate, and $0.03 million/year to
$0.08 million/year at a 7 percent rate. The two figures under each
discount scenario reflect an assumed latency period of 21 or 34 years.
Visibility Benefits--In addition to the human health benefits
discussed above, we also assessed visibility improvements. Particulate
matter emissions are a primary cause of reduced visibility. Changes in
the level of ambient particulate matter caused by the reduction in
emissions associated with the Agency preferred approach are expected to
increase the level of visibility in some parts of the United States. We
derived upper and lower bound benefits estimates associated with
particulate matter emissions

[[Page 21356]]

reductions using two different methodologies, each comparing reductions
to those associated with the Clean Air Act. The first approach assumes
a linear relationship between particulate matter reductions and
visibility improvements. Under this approach, the Agency preferred
replacement standards may result in a visibility benefit of
approximately $5.78 million per year. Our second approach is to assume
a linear relationship between health benefits and visibility benefits
associated with reduction in particulate matter emissions. Under this
approach, the proposed replacement standards could result in a
visibility benefit of approximately $0.11 million/year. This method
represents our lower bound estimate of visibility benefits.
2. Non-Monetized Benefits
We examined, but did not monetize human health benefits potentially
associated with reduced exposure to lead, mercury, and total chlorine.
Non monetized ecological benefits potentially associated with
reductions in dioxin/furan, selected metals, total chlorine, and
particulate matter were also examined. Finally, waste minimization is
examined as a non-monetized benefit.
Lead--The proposed replacement standards are expected to reduce
lead emissions by approximately five tons per year. In comparison, the
1999 standards were expected to reduce lead emissions by 89 tons per
year, and were expected to reduce cumulative lead exposures for two
children age 0-5 to less than 10 [mu]g/dL. The lead benefits associated
with the proposed replacement standards are therefore expected to be
modest, reducing the cumulative lead exposures for less than two
children age 0-5, less than 10 [mu]g/dL annually. The proposed
replacement standards will also result in reduced lead levels for
children of sub-populations with especially high levels of exposure.
Children of subsistence fishermen, commercial beef farmers, and
commercial dairy farmers who face the greatest levels of cumulative
lead exposure will also experience comparable reductions in overall
exposure as a result of the MACT standards.
Mercury--Mercury emitted from hazardous waste burning incinerators,
kilns, boilers, and other natural and man-made sources is carried by
winds through the air and eventually is deposited to water and land.
Recent estimates (which are highly uncertain) of annual total global
mercury emissions from all sources (natural and anthropogenic) are
about 5,000 to 5,500 tons per year (tpy). Of this total, about 1,000
tpy are estimated to be natural emissions and about 2,000 tpy are
estimated to be contributions through the natural global cycle of re-
emissions of mercury associated with past anthropogenic activity.
Current anthropogenic emissions account for the remaining 2,000 tpy.
Point sources such as fuel combustion; waste incineration; industrial
processes; and metal ore roasting, refining, and processing are the
largest point source categories on a world-wide basis. Given the global
estimates noted above, U.S. anthropogenic mercury emissions are
estimated to account for roughly 3 percent of the global total, and
U.S. hazardous waste burning incinerators, kilns, and boilers are
estimated to account for about 0.0045 percent of total global emissions.
Mercury exists in three forms: elemental mercury, inorganic mercury
compounds (primarily mercuric chloride), and organic mercury compounds
(primarily methylmercury). Mercury is usually released in an elemental
form and later converted into methylmercury by bacteria. Methylmercury
may be more toxic to humans than other forms of mercury, in part
because it is more easily absorbed in the body.\313\ If the deposition
is directly to a water body, then the processes of aqueous fate,
transport, and transformation begin. If deposition is to land, then
terrestrial fate and transport processes occur first and then aqueous
fate and transport processes occur once the mercury has cycled into a
water body. In both cases, mercury may be returned to the atmosphere
through resuspension. In water, mercury is transformed to methylmercury
through biological processes and for exposures affected by this
rulemaking. Methylmercury is considered to be the form of greatest
concern. Once mercury has been transformed into methylmercury, it can
be ingested by the lower trophic level organisms where it can
bioaccumulate in fish tissue (i.e., concentrations of mercury remain in
the fish's system for a long period of time and accumulates in the fish
tissue as predatory fish consume other species in the food chain). Fish
and wildlife at the top of the food chain can, therefore, have mercury
concentrations that are higher than the lower species, and they can
have concentrations of mercury that are higher than the concentration
found in the water body itself. In addition, when humans consume fish
containing methylmercury, the ingested methylmercury is almost
completely absorbed into the blood and distributed to all tissues
(including the brain); it also readily passes through the placenta to
the fetus and fetal brain.\314\
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\313\ Regulatory Impact Analysis of the Final Industrial Boilers
and Process Heaters NESHAP: Final Report, February 2004.
\314\ Regulatory Impact Analysis of the Final Industrial Boilers
and Process Heaters NESHAP: Final Report, February 2004.
---------------------------------------------------------------------------

Based on the findings of the National Research Council, EPA has
concluded that benefits of Hg reductions would be most apparent at the
human consumption stage, as consumption of fish is the major source of
exposure to methylmercury. At lower levels, documented Hg exposure
effects may include more subtle, yet potentially important,
neurodevelopmental effects.
Some subpopulations in the U.S., such as: Native Americans,
Southeast Asian Americans, and lower income subsistence fishers, may
rely on fish as a primary source of nutrition and/or for cultural
practices. Therefore, they consume larger amounts of fish than the
general population and may be at a greater risk to the adverse health
effects from Hg due to increased exposure. In pregnant women,
methylmercury can be passed on to the developing fetus, and at
sufficient exposure may lead to a number of neurological disorders in
children. Thus, children who are exposed to low concentrations of
methylmercury prenatally may be at increased risk of poor performance
on neurobehavioral tests, such as those measuring attention, fine motor
function, language skills, visual-spatial abilities (like drawing), and
verbal memory. The effects from prenatal exposure can occur even at
doses that do not result in effects in the mother. Mercury may also
affect young children who consume fish containing mercury. Consumption
by children may lead to neurological disorders and developmental
problems, which may lead to later economic consequences.
In response to potential risks of mercury-containing fish
consumption, EPA and FDA have issued fish consumption advisories which
provide recommended limits on consumption of certain fish species for
different populations. EPA and FDA have developed a new joint advisory
that was released in March 2004. This new FDA-EPA fish advisory
recommends that women and young children reduce the risks of Hg
consumption in their diet by moderating their fish consumption,
diversifying the types of fish they consume, and by checking any local
advisories that may exist for local rivers and streams. This
collaborative FDA-EPA effort will greatly assist in

[[Page 21357]]

educating the most susceptible populations. Additionally, the
reductions of Hg from this regulation may potentially lead to fewer
fish consumption advisories (both from federal or state agencies),
which will benefit the fishing community. Currently 44 states have
issued fish consumption advisories for non-commercial fish for some or
all of their waters due to contamination of mercury. The scope of FCA
issued by states varies considerably, with some warnings applying to
all water bodies in a state and others applying only to individual
lakes and streams. Note that the absence of a state advisory does not
necessarily indicate that there is no risk of exposure to unsafe levels
of mercury in recreationally caught fish. Likewise, the presence of a
state advisory does not indicate that there is a risk of exposure to
unsafe levels of mercury in recreationally caught fish, unless people
consume these fish at levels greater than those recommended by the fish
advisory.
Reductions in methylmercury concentrations in fish should reduce
exposure, subsequently reducing the risks of mercury-related health
effects in the general population, to children, and to certain
subpopulations. Fish consumption advisories (FCA) issued by the States
may also help to reduce exposures to potential harmful levels of
methylmercury in fish. To the extent that reductions in mercury
emissions reduces the probability that a water body will have a FCA
issued, there are a number of benefits that will result from fewer
advisories, including increased fish consumption, increased fishing
choices for recreational fishers, increased producer and consumer
surplus for the commercial fish market, and increased welfare for
subsistence fishing populations.
There is a great deal of variability among individuals in fish
consumption rates; however, critical elements in estimating
methylmercury exposure and risk from fish consumption include the
species of fish consumed, the concentrations of methylmercury in the
fish, the quantity of fish consumed, and how frequently the fish is
consumed. The typical U.S. consumer eating a wide variety of fish from
restaurants and grocery stores is not in danger of consuming harmful
levels of methylmercury from fish and is not advised to limit fish
consumption. Those who regularly and frequently consume large amounts
of fish, either marine or freshwater, are more exposed. Because the
developing fetus may be the most sensitive to the effects from
methylmercury, women of child-bearing age are regarded as the
population of greatest interest. The EPA, Food and Drug Administration,
and many States have issued fish consumption advisories to inform this
population of protective consumption levels.
The EPA's 1997 Mercury Study RTC supports a plausible link between
anthropogenic releases of Hg from industrial and combustion sources in
the U.S. and methylmercury in fish. However, these fish methylmercury
concentrations also result from existing background concentrations of
Hg (which may consist of Hg from natural sources, as well as Hg which
has been re-emitted from the oceans or soils) and deposition from the
global reservoir (which includes Hg emitted by other countries). Given
the current scientific understanding of the environmental fate and
transport of this element, it is not possible to quantify how much of
the methylmercury in locally-caught fish consumed by the U.S.
population is contributed by U.S. emissions relative to other sources
of Hg (such as natural sources and re-emissions from the global pool).
As a result, the relationship between Hg emission reductions from Phase
I and Phase II sources assessed in this rule, and methylmercury
concentrations in fish cannot be calculated in a quantitative manner
with confidence. In addition, there is uncertainty regarding over what
time period these changes would occur.
Given the present understanding of the Hg cycle, the flux of Hg
from the atmosphere to land or water at one location is comprised of
contributions from: the natural global cycle; the cycle perturbed by
human activities; regional sources; and local sources. Recent advances
allow for a general understanding of the global Hg cycle and the impact
of the anthropogenic sources. It is more difficult to make accurate
generalizations of the fluxes on a regional or local scale due to the
site-specific nature of emission and deposition processes. Similarly,
it is difficult to quantify how the water deposition of Hg leads to an
increase in fish tissue levels. This will vary based on the specific
characteristics of the individual lake, stream, or ocean.
Total Chlorine--We were not able to quantify the benefits
associated with reductions in total chlorine emissions. Total chlorine
is a combination of hydrogen chloride and chlorine gas. The replacement
standards proposed today are expected to reduce total chlorine
emissions by 2,638 tons. Hydrogen chloride is corrosive to the eyes,
skin, and mucous membranes. Acute inhalation can cause eye, nose, and
respiratory tract irritation and inflamation, and pulmonary edema.
Chronic occupational inhalation has been reported to cause gastritis,
bronchitis, and dermatitis in workers. Long term exposure can also
cause dental discoloration and erosion. No information is available on
the reproductive or developmental effects in humans. Chlorine gas
inhalation can cause bronchitis, asthma and swelling of the lungs,
headaches, heart disease, and meningitis. Acute exposure causes more
severe respiratory and lung effects, and can result in fatalities in
extreme cases. No information is available on the reproductive or
developmental effects in humans. The proposed replacement standards are
expected to reduce chlorine exposure for people in close proximity to
hazardous waste combustion facilities, and are therefore likely to
reduce the risk of all associated health effects.
Ecological Benefits--We examined ecological benefits through a
comparison of the 1999 Assessment and the proposed replacement
standards. Ecological benefits in the 1999 Assessment were based on
reductions of approximately 100 tons per year in dioxin/furans and
selected metals. Lead was the only pollutant of concern for aquatic
ecosystems, while mercury appeared to be of greatest concern for
terrestrial ecosystems. Dioxin/furan and lead emission reductions also
provided some potential benefits for terrestrial ecosystems. The
proposed replacement standards are expected to reduce dioxin/furan and
selected metal emissions by about 15 to 20 percent of the 1999
estimate. The proposed replacement standards will produce fewer
incremental benefits than those estimated for the 1999 Assessment (and
later, for the 2002 Interim Standards). However, the 1999 Assessment
did not estimate the ecological benefits of MACT standards for
industrial boilers and industrial furnaces. These systems were excluded
from the universe in 1999 but are part of the universe addressed by the
proposed replacement standards. As a result, while the total ecological
benefits of the proposed rule are likely to be modest, areas near
facilities with boilers may enjoy more significant ecological benefits
under the proposed replacement standards than areas near facilities
that have already complied with the 2002 Interim standards.
Mercury, lead, and chlorides are among the HAPs that can cause
damage to the health and visual appearance of

[[Page 21358]]

plants.\315\ While the total value of forest health is difficult to
estimate, visible deterioration in the health of forests and plants can
cause a measurable change in recreation behavior. Several studies that
measure the change in outdoor recreation behavior according to forest
health are available to place a value on aesthetic degradation of
forests.\316\ Although these studies are available, additional research
is needed to fully understand the effects of these HAPs on the forest
ecosystem. Thus, these benefits are not quantified in this analysis.
---------------------------------------------------------------------------

\315\ Although the primary pollutants which are detrimental to
vegetation aesthetics and growth are tropospheric ozone, sulfur
dioxide, and hydrogen fluoride, three pollutants which are not
regulated in the MACT standards, some literature exists on the
relationship between metal deposition and vegetation health.
(Mercury Study Report to Congress Volume VI, 1997) (Several studies
are cited in this report.)
\316\ See, for example, Brown, T.C. et al. 1989, Scenic Beauty
and Recreation Value: Assessing the Relationship, In J. Vining, ed.,
Social Science and Natural Resources Recreation Management, Westview
Press, Boulder, Colorado; this work studies the relationship between
forest characteristics and the value of recreational participation.
Also see Peterson, D.G. et al. 1987, Improving Accuracy and Reducing
Cost of Environmental Benefit Assessments. Draft Report to the U.S.
EPA, by Energy and Resource Consultants, Boulder, Colorado; Walsh et
al. 1990, Estimating the public benefits of protecting forest
quality, Journal of Forest Management, 30:175-189., and Homes et al.
1992, Economic Valuation of Spruce-Fir Decline in the Southern
Appalachian Mountains: A comparison of Value Elicitation Methods.
Presented at the Forestry and the Environment: Economic Perspectives
Conference, March 9-11, 1992 Jasper, Alberta, Canada for estimates
of the WTP of visitors and residents to avoid forest damage.
---------------------------------------------------------------------------

Emissions that are sufficient to cause structural and aesthetic
damage to vegetation are likely to affect growth as well. Little
research has been done on the effects of compounds such as chlorine,
heavy metals (as air pollutants), and PM on agricultural
productivity.\317\ Even though the potential for visible damage and
production decline from metals and other pollutants suggests the
proposed replacement standards could increase agricultural
productivity, these changes cannot be quantified.
---------------------------------------------------------------------------

\317\ MacKenzie, James J., and Mohamed T. El-Ashry, Air
Pollution's Toll on Forests and Crops (New Haven, Yale University
Press, 1989).
---------------------------------------------------------------------------

3. Waste Minimization Benefits
Facilities that burn hazardous waste and remain in operation
following implementation of the replacement standards are expected to
experience marginally increased costs as a result of the MACT
standards. This will result in an incentive to pass these increased
costs on to their customers in the form of higher combustion prices. In
the 1999 Assessment we conducted a waste minimization analysis to
inform the expected price change. The analysis concluded that the
demand for combustion is relatively inelastic. While a variety of waste
minimization alternatives are available for managing hazardous waste
streams that are currently combusted, the costs of these alternatives
generally exceed the cost of combustion. When the additional costs of
compliance with the MACT standards are taken into account, waste
minimization alternatives still tend to exceed the higher combustion
costs. This inelasticity suggests that, in the short term, large
reductions in waste quantities are not likely. However, over the longer
term (i.e., as production systems are updated), companies may continue
to seek alternatives to expensive waste-management (i.e., source
reduction). To the extent that increases in combustion prices provide
additional incentive to adopt more efficient processes, the proposed
replacement standards may contribute to the longer term process based
waste minimization efforts.
No waste minimization impacts are captured in our quantitative
analysis of costs and benefits. A quantitative assessment of the
benefits associated with waste minimization may result in double-
counting of some of the benefits described earlier. For example, waste
minimization may reduce emissions of hazardous air pollutants and
therefore have a positive effect on public health. Furthermore,
emission reductions beyond those necessary for compliance with the
replacement standards are not addressed in the benefits assessment. In
addition, waste minimization is likely to result in specific types of
benefits not captured in this Assessment. For example, waste generators
that engage in waste minimization may experience a reduction in their
waste handling costs and could also reduce the risk related to waste
spills and waste management. Finally, waste minimization procedures
potentially stimulated by today's action, as proposed, may result in
additional costs to facilities that implement these technologies. These
have not been assessed in our analysis but are likely to at least
partially offset corresponding benefits.
4. Conclusion
Total non-discounted monetized benefits are estimated to range from
$$4.6 million/year to $10.3 million/year. It is important to emphasize
that monetized benefits represent only a portion of the total benefits
associated with this rule. A significant portion of the benefits are
not monetized. Specifically, ecological benefits, and human health
benefits associated with reductions in chlorine, mercury, and lead are
not quantified or monetized. In some locations these benefits may be
significant. In addition, specific sub-populations near combustion
facilities, including children and minority populations, may be
disproportionately affected by environmental risks and may therefore
enjoy more significant benefits. For a complete discussion of the
methodology, data, findings, and limitations associated with our
benefits analysis the reader is encouraged to review the Assessment and
Addendum documents, as identified under Part Five, Section I.

IX. How Does the Proposed Rule Meet the RCRA Protectiveness Mandate?

As discussed in more detail below, we believe today's proposed
standards, based on evaluating estimated emissions from sources, are
generally protective. We therefore propose that these standards apply
in lieu of RCRA air emission standards in most instances.

A. Background

Section 3004(a) of RCRA requires the Agency to promulgate standards
for hazardous waste treatment, storage, and disposal facilities as
necessary to protect human health and the environment. The standards
for hazardous waste incinerators generally rest on this authority. In
addition, section 3004(q) requires the Agency to promulgate standards
for emissions from facilities that burn hazardous waste fuels (e.g.,
cement and lightweight aggregate kilns, boilers, and hydrochloric acid
production furnaces) as necessary to protect human health and the
environment. Using RCRA authority, the Agency has historically
established emission (and other) standards for hazardous waste
combustors that are either entirely risk-based (e.g., site-specific
standards for metals under the Boiler and Industrial Furnace rule), or
are technology-based but determined by a generic risk assessment to be
protective (e.g., the DRE standard for incinerators and BIFs).
The MACT standards proposed today implement the technology-based
regime of CAA section 112. There is, however, a residual risk component
to air toxics standards. Section 112(f) of the Clean Air Act requires
the Agency to impose, within eight years after promulgation of the
technology-based standards promulgated under section 112(d) (i.e., the
authority for today's proposed standards), additional controls if
needed to protect public health with an ample

[[Page 21359]]

margin of safety or to prevent adverse environmental effect.
RCRA section 1006 directs that EPA ``integrate all provisions of
[RCRA] for purposes of administration and enforcement and . . . avoid
duplication, to the maximum extent possible, with the appropriate
provisions of the Clean Air Act. . . .'' Thus, although considerations
of risk are not ordinarily part of the MACT process, in order to avoid
duplicative standards where possible, we have evaluated the
protectiveness of the standards proposed today.
As noted above, under RCRA, EPA must promulgate standards ``as may
be necessary to protect human health and the environment.'' RCRA
section 3004(a) and (q). Technology-based standards developed under CAA
section 112 do not automatically satisfy this requirement, but may do
so in fact. See 59 FR at 29776 (June 6, 1994) and 60 FR at 32593 (June
23, 1995) (RCRA regulation of secondary lead smelter emissions
unnecessary at this time given stringency of technology-based standard
and pendency of section 112(f) determination). If the MACT standards,
as a factual matter, are sufficiently protective to also satisfy the
RCRA mandate, then no independent RCRA standards are required.
Conversely, if MACT standards are inadequate, the RCRA authorities
would have to be used to fill the gap.

B. Assessment of Risks

The Agency has conducted an evaluation, for the purposes of
satisfying the RCRA statutory mandates, of the degree of protection
afforded by the MACT standards being proposed today. We have not
conducted a comprehensive risk assessment for this proposal; however, a
comprehensive risk assessment for incinerators, cement kilns, and
lightweight aggregate kilns was conducted for the 1999 MACT rule. For
this proposed rule, we are instead comparing characteristics of the
sources covered by the 1999 rule to the sources covered by the
replacement rule that are related to risk (e.g., emissions\318\, stack
characteristics, meteorology, and population). In the 1999 rule we
concluded that the promulgated standards were sufficiently protective
and the existing RCRA standards for incinerators, cement kilns, and
lightweight aggregate kilns need not be retained. Based on the results
of statistical comparisons, we infer whether risks for incinerators,
cement kilns, lightweight aggregate kilns, boilers, and hydrochloric
acid production furnaces will be about the same, less than, or greater
than the risks estimated for the 1999 rule. We think the comparative
analysis lends additional support to our view regarding the
protectiveness of the proposed standards.\319\
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\318\ We estimated emissions for each facility based on site-
specific stack gas concentrations and flow rates measured during
trial burn or compliance tests. For sources where stack gas
measurements were unavailable, data were imputed by random selection
from a pool of measurements for similar units. We assumed that
sources would design their systems to meet an emission level below
the proposed standard. (In the case of dioxin/furan for sources that
would not be subject to a numerical emission standard, we assumed
liquid boilers without dry air pollution control systems and solid
fuel-fired boilers were emitting at their baseline emissions level
as portrayed in the data base.) We called this the ``design level.''
If available test data in our data base indicate that the source was
emitting below the design level, we assumed that the source would
continue to emit at the levels measured in test. For sources
emitting above the design level of a standard, we assumed they would
need to reduce emissions to the design level. In the 1999 rule, the
design level was taken as 70% of the standard. For today's proposed
standards, the design level is generally the lower of: (1) 70% of
the standard; or (2) the arithmetic average of the emissions data of
the best performing sources.
\319\ See ``Inferential Risk Analysis in Support of Standards
for Emissions of Hazardous Air Pollutants from Hazardous Waste
Combustors,'' prepared under contract to EPA by Research Triangle
Institute, Research Triangle Park, NC.
---------------------------------------------------------------------------

We believe today's proposed standards provide a substantial degree
of protection to human health and the environment. We therefore do not
believe that we need to retain the existing RCRA standards for boilers
and hydrochloric acid production furnaces (just as we found that
existing RCRA standards for incinerators, cement kilns, and lightweight
aggregate kilns were no longer needed after the 1999 rule). However, as
previously discussed in more detail in Part Two, Section XVII.D, site-
specific risk assessments may be warranted on an individual source
basis to ensure that the MACT standards provide adequate protection in
accordance with RCRA.

Part Five: Administrative Requirements

I. Executive Order 12866: Regulatory Planning and Review

Under Executive Order 12866 [58 FR 51735 (October 4, 1993)], the
Agency must determine whether a regulatory action is ``significant''
and therefore subject to OMB review and the requirements of the
Executive Order. The Order defines ``significant regulatory action'' as
one that is likely to result in a rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or communities;
(2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency;
(3) Materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
Pursuant to the terms of Executive Order 12866, it has been
determined that this rule is a ``significant regulatory action''
because this action may raise novel legal or policy issues due to the
standards development methodology applied in development of the
proposed replacement standards. As such, this action was submitted to
OMB for review. Changes made in response to OMB suggestions or
recommendations will be documented in the public record.
The aggregate annualized social costs for this rule are under $100
million (ranging from $41 to $50 million/yr). We have prepared an
economic assessment in support of today's action. This document is
entitled: Assessment of the Potential Costs, Benefits, and Other
Impacts of the Hazardous Waste Combustion MACT Replacement Standards--
Proposed Rule, March 2004. This Assessment is designed to adhere to
analytical requirements established under Executive Order 12866, and
corresponding Agency and OMB guidance; subject to data, analytical, and
resource limitations. An Addendum entitled: Addendum to the Assessment
of the Potential Costs, Benefits, and Other Impacts of the Hazardous
Waste Combustion MACT Replacement Standards--Proposed Rule, March 2004,
has also been prepared. This Addendum addresses belated changes made to
the final proposed standards that were not captured in the Assessment.
The RCRA docket established for today's rulemaking maintains a copy of
the Assessment and Addendum documents for public review. Interested
persons are encouraged to read both documents for a full understanding
of the analytical methodology, findings, and limitations associated
with this report. Comments and supporting data are encouraged and welcomed.

II. Paperwork Reduction Act

The information collection requirements in this proposed rule have
been submitted for approval to the Office of Management and Budget
(OMB) under the Paperwork Reduction

[[Page 21360]]

Act, 44 U.S.C. 3501 et seq. The Information Collection Request (ICR)
document prepared by EPA has been assigned EPA ICR number 1773.07.
EPA is proposing today's regulations under section 112 of the CAA,
to protect and enhance the quality of our nation's air resources, and
to promote public health and welfare and the productive capacity of the
population. See CAA section 101(b)(1). To this end, CAA sections 112(a)
and (d) direct EPA to set standards for stationary sources emitting the
hazardous air pollutants. The records and reports required by the
information collection under this proposal will be used to show
compliance with the requirements of the rule. EPA believes that if
these minimum requirements specified under the regulations are not met,
EPA will not fulfill its Congressional mandate to protect public health
and the environment.
The information collection required under this ICR is mandatory for
the regulated sources as it is essential to properly enforce the
emission limitation requirements of the rule and will be used to
further the proper performance of the functions of EPA. EPA has made
extensive efforts to integrate the monitoring, compliance testing and
recordkeeping requirements of the CAA and RCRA, so that the burden on
the sources is kept to a minimum, and the facilities are able to avoid
duplicate and unnecessary submissions. We also ensure, to the fullest
extent of the law, the confidentiality of the submitted information.
The projected annual burden under today's proposal is estimated at
70,199 hours at a total cost of $5.1 millions. For the hour burden, we
estimate a total of 2,612 responses from 243 respondents, or an average
of 27 hours per response, or 289 hours per respondent. The cost burden
to respondents or recordkeepers resulting from the collection of
information includes a total capital and start-up cost component, a
total operation and maintenance component and a purchase of services
component. The capital and start-up cost component is estimated at
$36,184 annualized over its expected useful life, and the operation and
maintenance component is estimated at $488,947 annualized over its
expected useful life. The frequency of different responses varies and
is monthly or annually for some and on occasion for others.
Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal agency. This includes the time
needed to review instructions; develop, acquire, install, and utilize
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
An agency may not conduct or sponsor, and a person is not required
to respond to a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR are listed in 40 CFR part 9.
To comment on the Agency's need for this information, the accuracy
of the provided burden estimates, and any suggested methods for
minimizing respondent burden, including the use of automated collection
techniques, EPA has established a public docket for this rule, which
includes this ICR, under Docket ID number RCRA-2003-0016. Submit any
comments related to the ICR for this proposed rule to EPA and OMB. See
Addresses section at the beginning of this notice for where to submit
comments to EPA. Send comments to OMB at the Office of Information and
Regulatory Affairs, Office of Management and Budget, 725 17th Street,
NW., Washington, DC 20503, Attention: Desk Office for EPA. Since OMB is
required to make a decision concerning the ICR between 30 and 60 days
after April 20, 2004, a comment to OMB is best assured of having its
full effect if OMB receives it by May 20, 2004. The final rule will
respond to any OMB or public comments on the information collection
requirements contained in this proposal.

III. Regulatory Flexibility Act

The Regulatory Flexibility Act (RFA) as amended by the Small
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C.
601 et seq. generally requires an agency to prepare a regulatory
flexibility analysis of any rule subject to notice and comment
rulemaking requirements under the Administrative Procedure Act, or any
other statute. This analysis must be completed unless the agency is
able to certify that the rule will not have a significant economic
impact on a substantial number of small entities. Small entities
include small businesses, small not-for-profit enterprises, and small
governmental jurisdictions.
We have determined that hazardous waste combustion facilities are
not owned by small entities (local governments, tribes, etc.) other
than businesses. Therefore, only businesses were analyzed for small
entity impacts. For the purposes of the impact analyses, small entity
is defined either by the number of employees or by the dollar amount of
sales. The level at which a business is considered small is determined
for each North American Industrial Classification System (NAICS) code
by the Small Business Administration.
Affected individual waste combustors (incinerators, cement kilns,
lightweight aggregate kilns, solid and liquid fuel-fired boilers, and
hydrochloric acid production furnaces) will bear the impacts of today's
rule. These units will incur direct economic impacts as a result of
today's rule. Few of the hazardous waste combustion facilities affected
by this proposed rule were found to be owned by small businesses, as
defined by the Small Business Administration (SBA). From our universe
of 150 facilities, we identified six facilities that are currently
owned by small businesses. Three of these are liquid boilers, one is an
on-site incinerator, one is a cement kiln, and one is an LWAK.
Annualized economic impacts of the proposed replacement standards were
found to range from 0.01 percent to 2.23 percent of gross annual
corporate revenues. Economic impacts to five of the companies were
found to be less than one percent, while the sixth company was found to
experience potential impacts between one and 3 percent (2.23 percent).
These findings reflect worst-case cost estimates under the Agency
Preferred Approach. Actual economic impacts are likely to be less as
market adjustments take effect (see appendix H of the Assessment and
Assessment of Small Entity Impacts in the Addendum).
Based on the above findings we believe that one small company with
potential impacts between one and 3 percent of gross revenues does not
reflect a significant economic impact on a substantial number of
potentially affected small entities. Therefore, after considering the
economic impacts of today's proposed rule on small entities, I certify
that this action will not have a significant economic impact on a
substantial number of small entities. The reader is encouraged to
review and comment on our regulatory flexibility screening analysis
prepared in support of this determination: Regulatory Flexibility
Screening Analysis for the Proposed Hazardous Waste Combustion MACT
Replacement Standards. This

[[Page 21361]]

document is incorporated as Appendix H of the Assessment document.

IV. Unfunded Mandates Reform Act

Signed into law on March 22, 1995, the Unfunded Mandates Reform Act
(UMRA) calls on all federal agencies to provide a statement supporting
the need to issue any regulation containing an unfunded federal mandate
and describing prior consultation with representatives of affected
state, local, and tribal governments.
Today's proposed rule is not subject to the requirements of
sections 202, 204 and 205 of UMRA. In general, a rule is subject to the
requirements of these sections if it contains ``Federal mandates'' that
may result in the expenditure by State, local, and tribal governments,
in the aggregate, or by the private sector, of $100 million or more in
any one year. Today's final rule does not result in $100 million or
more in expenditures. The aggregate annualized social cost for today's
rule is estimated to range from $41 to $50 million.

V. Executive Order 13132: Federalism

Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
Under Executive Order 13132, EPA may not issue a regulation that
has federalism implications, that imposes substantial direct compliance
costs, and that is not required by statute, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by State and local governments, or EPA consults with
State and local officials early in the process of developing the
proposed regulation.
This proposed rule does not have federalism implications. It will
not have substantial direct effects on the States, on the relationship
between the national government and the States, or on the distribution
of power and responsibilities among the various levels of government,
as specified in the Order. The proposed rule focuses on requirements
for facilities burning hazardous waste, without affecting the
relationships between Federal and State governments. Thus, Executive
Order 13132 does not apply to this rule. Although section 6 of
Executive Order 13132 does not apply to this rule, EPA did include
three State representatives on our Agency workgroup. These
representatives participated in the development of this proposed rule.
State officials were contacted concerning the methodology used in
standards development.
In the spirit of Executive Order 13132, and consistent with EPA
policy to promote communications between EPA and State and local
governments, EPA specifically solicits comment on this proposed rule
from State and local officials.

VI. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

Executive Order 13175 \320\: Consultation and Coordination with
Indian Tribal Governments (65 FR 67249, November 9, 2000), requires EPA
to develop an accountable process to ensure ``meaningful and timely
input by tribal officials in the development of regulatory policies
that have tribal implications.'' Our Agency workgroup for this
rulemaking includes Tribal representation. We have determined that this
rule, as proposed, does not have tribal implications, as specified in
the Order. No Tribal governments are known to own or operate hazardous
waste combustors subject to the requirements of this proposed rule.
Furthermore, this proposed rule focuses on requirements for all
regulated sources without affecting the relationships between tribal
governments in its implementation, and applies to all regulated
sources, without distinction of the surrounding populations affected.
Thus, Executive Order 13175 does not apply to this rule. EPA
specifically solicits additional comment on this proposed rule from
tribal officials.
---------------------------------------------------------------------------

\320\ Executive Order 13084 is revoked by this Executive Order.
---------------------------------------------------------------------------

VII. Executive Order 13045: Protection of Children From Environmental
Health and Safety Risks

Executive Order 13045: ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR. 19885, April 23, 1997) applies
to any rule that: (1) Is determined to be ``economically significant''
as defined under E.O. 12866, and (2) concerns an environmental health
or safety risk that EPA has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the Agency must evaluate the environmental health or
safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency. Today's
final rule is not subject to the Executive Order because it is not
economically significant as defined under point one of the Order, and
because the Agency does not have reason to believe the environmental
health or safety risks addressed by this action present a
disproportionate risk to children.

VIII. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

This rule is not subject to Executive Order 13211, ``Actions
Concerning Regulations That Significantly Affect Energy Supply,
Distribution, or Use'' (66 FR 28355 (May 22, 2001)). This rule, as
proposed will not seriously disrupt energy supply, distribution
patterns, prices, imports or exports. Furthermore, this rule is not an
economically significant action under Executive Order 12866.

IX. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note)
directs EPA to use voluntary consensus standards in its regulatory
activities unless to do so would be inconsistent with applicable law or
otherwise impractical. Voluntary consensus standards are technical
standards (e.g., materials specifications, test methods, sampling
procedures, and business practices) that are developed or adopted by
voluntary consensus standards bodies. The NTTAA directs EPA to provide
Congress, through OMB, explanations when the Agency decides not to use
available and applicable voluntary consensus standards.
This proposed rulemaking involves environmental monitoring or
measurement. Consistent with the Agency's Performance Based Measurement
System (``PBMS''), EPA proposes not to require the use of specific,
prescribed analytic methods. Rather, the Agency plans to allow the use
of any method that meets the prescribed performance criteria. The PBMS
approach is intended to be more flexible and cost-effective for the
regulated community; it is also intended to encourage innovation in
analytical technology and improved data quality. EPA is not precluding
the use of any method, whether it constitutes a

[[Page 21362]]

voluntary consensus standard or not, as long as it meets the
performance criteria specified.
EPA welcomes comments on this aspect of the proposed rulemaking
and, specifically, invites the public to identify potentially-
applicable voluntary consensus standards and to explain why such
standards should be used in this regulation.

X. Executive Order 12898: Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations

Executive Order 12898, ``Federal Actions To Address Environmental
Justice in Minority Populations and Low-Income Populations'' (February
11, 1994) requires us to complete an analysis of today's rule with
regard to equity considerations. The Order is designed to address the
environmental and human health conditions of minority and low-income
populations. This section briefly discusses potential impacts (direct
or disproportional) today's rule may have in the area of environmental
justice.
To comply with the Executive Order, we have assessed whether
today's rule may have negative or disproportionate effects on minority
or low-income populations. We have recently analyzed demographic data
from the U.S. Census. Previously we examined data from two other
reports: ``Race, Ethnicity, and Poverty Status of the Populations
Living Near Cement Plants in the United States'' (EPA, August 1994) and
``Race, Ethnicity, and Poverty Status of the Populations Living Near
Hazardous Waste Incinerators in the United States'' (EPA, October
1994). These reports examine the number of low-income and minority
individuals living near a relatively large sample of cement kilns and
hazardous waste incinerators and provide county, state, and national
population percentages for various sub-populations. The demographic
data in these reports provide several important findings when examined
in conjunction with the risk reductions projected from today's rule.
We find that combustion facilities, in general, are not located in
areas with disproportionately high minority and low-income populations.
However, there is evidence that hazardous waste burning cement kilns
are somewhat more likely to be located in areas that have relatively
higher low-income populations. Furthermore, there are a small number of
commercial hazardous waste incinerators located in highly urbanized
areas where there is a disproportionately high concentration of
minorities and low-income populations within one and five mile radii.
The reduced emissions at these facilities due to today's rule could
represent meaningful environmental and health improvements for these
populations. Overall, today's rule should not result in any adverse or
disproportional health or safety effects on minority or low-income
populations. Any impacts on these populations are likely to be positive
due to the reduction in emissions from combustion facilities near
minority and low-income population groups. The Assessment document
available in the RCRA docket established for today's rule presents the
full Environmental Justice Analysis.

XI. Congressional Review

The Congressional Review Act (CRA), 5 U.S.C. 801 et seq., as added
by the Small Business Regulatory Enforcement Fairness Act of 1996,
generally provides that before a rule may take effect, the agency
promulgating the rule must submit a rule report, which includes a copy
of the rule, to each House of the Congress and to the Comptroller
General of the United States. Prior to publication of the final rule in
the Federal Register, we will submit all necessary information to the
U.S. Senate, the U.S. House of Representatives, and the Comptroller
General of the United States. Under the CRA, a major rule cannot take
effect until 60 days after it is published in the Federal Register. As
proposed, this action is not a ``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects

40 CFR Part 63

Environmental protection, Air pollution control, Hazardous
substances, Incorporation by reference, Reporting and recordkeeping
requirements.

40 CFR Part 264

Environmental protection, Air pollution control, Hazardous waste,
Insurance, Packaging and containers, Reporting and recordkeeping
requirements, Security measures, Surety bonds.

40 CFR Part 265

Environmental protection, Air pollution control, Hazardous waste,
Insurance, Packaging and containers, Reporting and recordkeeping
requirements.

40 CFR Part 266

Environmental protection, Energy, Hazardous waste, Recycling,
Reporting and recordkeeping requirements.

40 CFR Part 270

Environmental protection, Administrative practice and procedure,
Confidential business information, Hazardous materials transportation,
Hazardous waste, Reporting and recordkeeping requirements.

40 CFR Part 271

Administrative practice and procedure, Hazardous materials
transportation, Hazardous waste, Intergovernmental relations, Reporting
and recordkeeping requirements.

Dated: March 31, 2004.
Michael O. Leavitt,
Administrator.
For the reasons set out in the preamble, title 40, chapter I, of
the Code of Federal Regulations is proposed to be amended as follows:

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS
FOR SOURCE CATEGORIES

1. The authority citation for part 63 continues to read as follows:

Authority: 42 U.S.C. 7401 et seq.

2. Section 63.1200 is amended by revising the introductory text and
paragraph (a)(2) to read as follows:

Sec. 63.1200 Who is subject to these regulations?

The provisions of this subpart apply to all hazardous waste
combustors: incinerators that burn hazardous waste, cement kilns that
burn hazardous waste, lightweight aggregate kilns that burn hazardous
waste, solid fuel-fired boilers that burn hazardous waste, liquid fuel-
fired boilers that burn hazardous waste, and hydrochloric acid
production furnaces that burn hazardous waste. Hazardous waste
combustors are also subject to applicable requirements under parts 260-
270 of this chapter.
(a) * * *
(2) Both area sources and major sources subject to this subpart,
but not previously subject to title V, are immediately subject to the
requirement to apply for and obtain a title V permit in all States, and
in areas covered by part 71 of this chapter.
* * * * *
3. Section 63.1201 is amended in paragraph (a) by revising the
definition of ``New source'', and adding definitions for ``Hydrochloric
acid production furnace'', ``Liquid fuel-fired boiler'', and ``Solid
fuel-fired boiler'' in alphabetical order to read as follows:

Sec. 63.1201 Definitions and acronyms used in this subpart.

(a) * * *

[[Page 21363]]

Hydrochloric acid production furnace and HCl production furnace
mean a halogen acid furnace defined in Sec. 260.10 of this chapter
that produces aqueous hydrochloric acid (HCl) product and that burns
hazardous waste at any time.
* * * * *
Liquid fuel-fired boiler and liquid boiler mean a boiler defined in
Sec. 260.10 of this chapter that does not burn solid fuels and that
burns hazardous waste at any time. Liquid fuel-fired boiler includes
boilers that only burn gaseous fuels.
* * * * *
New source means any affected source the construction or
reconstruction of which is commenced after the dates specified under
Sec. Sec. 63.1206(a)(1)(i)(B), (a)(1)(ii)(B), and (a)(2)(ii).
* * * * *
Solid fuel-fired boiler and solid boiler mean a boiler defined in
Sec. 260.10 of this chapter that burns a solid fuel and that burns
hazardous waste at any time.
* * * * *
4. Section 63.1206 is amended by:
a. Revising paragraph (a).
b. Revising paragraphs (b)(1)(ii), (b)(6) introductory text,
(b)(7)(i)(A), (b)(9)(i) introductory text, (b)(10)(i) introductory
text, (b)(11), (b)(13)(i) introductory text, and (b)(3)(ii).
c. Revising paragraphs (c)(1)(i) introductory text and (c)(7)(ii)
introductory text.
d. Adding paragraphs (c)(7)(ii)(C) and (c)(7)(iii).
The revisions and additions read as follows:

Sec. 63.1206 When and how must you comply with the standards and
operating requirements?

(a) Compliance dates. (1) Compliance dates for incinerators, cement
kilns, and lightweight aggregate kilns that burn hazardous waste--(i)
Compliance date for standards under Sec. Sec. 63.1203, 63.1204, and
63.1205--(A) Compliance dates for existing sources. You must comply
with the emission standards under Sec. Sec. 63.1203, 63.1204, and
63.1205 and the other requirements of this subpart no later than the
compliance date, September 30, 2003, unless the Administrator grants
you an extension of time under Sec. 63.6(i) or Sec. 63.1213.
(B) New or reconstructed sources. (1) If you commenced construction
or reconstruction of your hazardous waste combustor after April 19,
1996, you must comply with the emission standards under Sec. Sec.
63.1203, 63.1204, and 63.1205 and the other requirements of this
subpart by the later of September 30, 1999 or the date the source
starts operations, except as provided by paragraph (a)(1)(i)(B)(2) of
this section. The costs of retrofitting and replacement of equipment
that is installed specifically to comply with this subpart, between
April 19, 1996 and a source's compliance date, are not considered to be
reconstruction costs.
(2) For a standard under Sec. Sec. 63.1203, 63.1204, and 63.1205
that is more stringent than the standard proposed on April 19, 1996,
you may achieve compliance no later than September 30, 2003 if you
comply with the standard proposed on April 19, 1996 after September 30,
1999. This exception does not apply, however, to new or reconstructed
area source hazardous waste combustors that become major sources after
September 30, 1999. As provided by Sec. 63.6(b)(7), such sources must
comply with the standards under Sec. Sec. 63.1203, 63.1204, and
63.1205 at startup.
(ii) Compliance date for standards under Sec. Sec. 63.1219,
63.1220, and 63.1221--(A) Compliance dates for existing sources. You
must comply with the emission standards under Sec. Sec. 63.1219,
63.1220, and 63.1221 and the other requirements of this subpart no
later than the compliance date, [date three years after date of
publication of the final rule in the Federal Register], unless the
Administrator grants you an extension of time under Sec. 63.6(i) or
Sec. 63.1213.
(B) New or reconstructed sources. (1) If you commenced construction
or reconstruction of your hazardous waste combustor after April 20,
2004, you must comply with the emission standards under Sec. Sec.
63.1219, 63.1220, and 63.1221 and the other requirements of this
subpart by the later of [date of publication of the final rule in the
Federal Register] or the date the source starts operations, except as
provided by paragraph (a)(1)(ii)(B)(2) of this section. The costs of
retrofitting and replacement of equipment that is installed
specifically to comply with this subpart, between April 20, 2004, and a
source's compliance date, are not considered to be reconstruction costs.
(2) For a standard under Sec. Sec. 63.1219, 63.1220, and 63.1221
that is more stringent than the standard proposed on April 20, 2004,
you may achieve compliance no later than [date three years after date
of publication of the final rule in the Federal Register] if you comply
with the standard proposed on April 20, 2004, after [date of
publication of the final rule in the Federal Register]. This exception
does not apply, however, to new or reconstructed area source hazardous
waste combustors that become major sources after [date three years
after date of publication of the final rule in the Federal Register].
As provided by Sec. 63.6(b)(7), such sources must comply with the
standards under Sec. Sec. 63.1219, 63.1220, and 63.1221 at startup.
(2) Compliance dates for solid fuel-fired boilers, liquid fuel-
fired boilers, and hydrogen chloride production furnaces that burn
hazardous waste for standards under Sec. Sec. 63.1216, 63.1217, and
63.1218.--(i) Compliance date for existing sources. You must comply
with the standards of this subpart no later than the compliance date,
[date three years after date of publication of the final rule in the
Federal Register], unless the Administrator grants you an extension of
time under Sec. 63.6(i) or Sec. 63.1213.
(ii) New or reconstructed sources. (A) If you commenced
construction or reconstruction of your hazardous waste combustor after
April 20, 2004, you must comply with this subpart by the later of [date
of publication of the final rule in the Federal Register] or the date
the source starts operations, except as provided by paragraph
(a)(2)(ii)(B) of this section. The costs of retrofitting and
replacement of equipment that is installed specifically to comply with
this subpart, between April 20, 2004, and a source's compliance date,
are not considered to be reconstruction costs.
(B) For a standard in the subpart that is more stringent than the
standard proposed on April 20, 2004, you may achieve compliance no
later than [date three years after date of publication of the final
rule in the Federal Register] if you comply with the standard proposed
on April 20, 2004, after [date of publication of the final rule in the
Federal Register]. This exception does not apply, however, to new or
reconstructed area source hazardous waste combustors that become major
sources after [date three years after date of publication of the final
rule in the Federal Register]. As provided by Sec. 63.6(b)(7), such
sources must comply with this subpart at startup.
(3) Early compliance. If you choose to comply with the emission
standards of this subpart prior to the dates specified in paragraphs
(a)(1) and (a)(2) of this section, your compliance date is the earlier
of the date you postmark the Notification of Compliance under Sec.
63.1207(j)(1) or the dates specified in paragraphs (a)(1) and (a)(2) of
this section.
(b) * * *
(1) * * *
(ii) When hazardous waste is not in the combustion chamber (i.e.,
the hazardous waste feed to the combustor has been cut off for a period
of time not less than the hazardous waste residence

[[Page 21364]]

time) and you have documented in the operating record that you are
complying with all otherwise applicable requirements and standards
promulgated under authority of sections 112 (e.g., subparts LLL, NNNNN,
DDDDD) or 129 of the Clean Air Act in lieu of the emission standards
under Sec. Sec. 63.1203, 63.1204, 63.1205, 63.1215, 63.1216, 63.1217,
63.1218, 63.1219, and 63.1220; the monitoring and compliance standards
of this section and Sec. Sec. 63.1207 through 63.1209, except the
modes of operation requirements of Sec. 63.1209(q); and the
notification, reporting, and recordkeeping requirements of Sec. Sec.
63.1210 through 63.1212.
* * * * *
(6) Compliance with the carbon monoxide and hydrocarbon emission
standards. This paragraph applies to sources that elect to comply with
the carbon monoxide and hydrocarbon emissions standards of this subpart
by documenting continuous compliance with the carbon monoxide standard
using a continuous emissions monitoring system and documenting
compliance with the hydrocarbon standard during the destruction and
removal efficiency (DRE) performance test or its equivalent.
* * * * *
(7) * * * (i) * * *
(A) You must document compliance with the Destruction and Removal
Efficiency (DRE) standard under this subpart only once provided that
you do not modify the source after the DRE test in a manner that could
affect the ability of the source to achieve the DRE standard.
* * * * *
(9) * * * (i) You may petition the Administrator to recommend
alternative semivolatile metal, low volatile metal, mercury, or
hydrogen chloride/chlorine gas emission standards under Sec. 63.1205 if:
* * * * *
(10) * * * (i) You may petition the Administrator to recommend
alternative semivolatile metal, low volatile metal, mercury, or
hydrogen chloride/chlorine gas emission standards under Sec. 63.1204 if:
* * * * *
(11) Calculation of hazardous waste residence time. You must
calculate the hazardous waste residence time and include the
calculation in the performance test plan under Sec. 63.1207(f) and the
operating record. You must also provide the hazardous waste residence
time in the Documentation of Compliance under Sec. 63.1211(d) and the
Notification of Compliance under Sec. Sec. 63.1207(j) and 63.1210(d).
* * * * *
(13) * * *
(i) Cement kilns that feed hazardous waste at a location other than
the end where products are normally discharged and where fuels are
normally fired must comply with the carbon monoxide and hydrocarbon
standards of this subpart as follows:
* * * * *
(ii) Lightweight aggregate kilns that feed hazardous waste at a
location other than the end where products are normally discharged and
where fuels are normally fired must comply with the hydrocarbon
standards of this subpart as follows:
(A) Existing sources must comply with the 20 parts per million by
volume hydrocarbon standard of this subpart;
(B) New sources must comply with the 20 parts per million by volume
hydrocarbon standard of this subpart.
* * * * *
(c) * * * (1) * * * (i) You must operate only under the operating
requirements specified in the Documentation of Compliance under Sec.
63.1211(d) or the Notification of Compliance under Sec. Sec.
63.1207(j) and 63.1210(d), except:
* * * * *
(7) * * *
(ii) Bag leak detection system requirements. If your combustor is
equipped with a baghouse (fabric filter), you must continuously operate
a bag leak detection system that meets the specifications and
requirements of paragraph (c)(7)(ii)(A) of this section and you must
comply with the corrective measures requirements of paragraph
(c)(7)(ii)(B) of this section.
* * * * *
(C) Excessive exceedances notification. If you operate the
combustor when the detector response exceeds the alarm set-point more
than 5 percent of the time during any 6-month block time period, you
must submit a notification to the Administrator within 5 days that
describes the causes of the exceedances and the revisions to the
design, operation, or maintenance of the combustor or baghouse you are
taking to minimize exceedances.
(iii) Particulate matter detection system requirements for
electrostatic precipitators and ionizing wet scrubbers. If your
combustor is equipped with an electrostatic precipitator or ionizing
wet scrubber, and you elect not to establish under Sec.
63.1209(m)(1)(iv) site-specific operating parameter limits that are
linked to the automatic waste feed cutoff system under paragraph (c)(3)
of this section, you must continuously operate a particulate matter
detection system that meets the specifications and requirements of
paragraph (c)(7)(iii)(A) of this section and you must comply with the
corrective measures requirements of paragraph (c)(7)(iii)(B) of this section.
(A) Particulate matter detection system requirements.--(1) The
particulate matter detection system must be certified by the
manufacturer to be capable of continuously detecting and recording
particulate matter emissions at the loadings you expect to achieve
during the comprehensive performance test;
(2) The particulate matter detector shall provide output of
relative or absolute particulate matter loadings;
(3) The particulate matter detection system shall be equipped with
an alarm system that will sound an audible alarm when an increase in
relative or absolute particulate loadings is detected over the set-point
(4) You must install and operate the particulate matter detection
system in a manner consistent with available written guidance from the
U.S. Environmental Protection Agency or, in the absence of such written
guidance, the manufacturer's written specifications and recommendations
for installation, operation, and adjustment of the system;
(5) You must establish the alarm set-point as the average detector
response of the test run averages achieved during the comprehensive
performance test demonstrating compliance with the particulate matter
emission standard. You must comply with the alarm set-point on a 6-hour
rolling average, updated each hour with a one-hour block average that
is the average of the detector responses over each 15-minute block.
(6) Where multiple detectors are required to monitor multiple
control devices, the system's instrumentation and alarm system may be
shared among the detectors.
(B) Particulate matter detection system corrective measures
requirements. The operating and maintenance plan required by paragraph
(c)(7)(i) of this section must include a corrective measures plan that
specifies the procedures you will follow in the case of a particulate
matter detection system alarm. The corrective measures plan must
include, at a minimum, the procedures used to determine and record the
time and cause of the alarm as well as the corrective measures taken to
correct the control device malfunction or minimize emissions as

[[Page 21365]]

specified below. Failure to initiate the corrective measures required
by this paragraph is failure to ensure compliance with the emission
standards in this subpart.
(1) You must initiate the procedures used to determine the cause of
the alarm within 30 minutes of the time the alarm first sounds; and
(2) You must alleviate the cause of the alarm by taking the
necessary corrective measure(s) which may include shutting down the
combustor.
(C) Excessive exceedances notification. If you operate the
combustor when the detector response exceeds the alarm set-point more
than 5 percent of the time during any 6-month block time period, you
must submit a notification to the Administrator within 5 days that
describes the causes of the exceedances and the revisions to the
design, operation, or maintenance of the combustor or electrostatic
precipitator or ionizing wet scrubber you are taking to minimize exceedances.
5. Section 63.1207 is amended by:
a. Revising paragraph (b)(1).
b. Adding paragraph (b)(3).
c. Revising paragraph (c)(1).
d. Adding paragraph (c)(3).
e. Revising paragraphs (e)(2) and (e)(3)(iv).
f. Revising paragraphs (f)(1)(ii)(D ), (f)(1)(xiii), and
(f)(1)(xiv).
g. Adding paragraph (f)(1)(xv).
h. Revising paragraphs (j)(1)(ii) and (j)(3).
i. Revising paragraph (l)(1) introductory text.
The revisions and additions read as follows:

Sec. 63.1207 What are the performance testing requirements?

* * * * *
(b) * * *
(1) Comprehensive performance test. You must conduct comprehensive
performance tests to demonstrate compliance with the emission standards
provided by the subpart, establish limits for the operating parameters
provided by Sec. 63.1209, and demonstrate compliance with the
performance specifications for continuous monitoring systems.
* * * * *
(3) One-Time Dioxin/Furan Test for Boilers Not Subject to a
Numerical Dioxin/Furan Standard. For boilers that are not subject to a
numerical dioxin/furan emission standard under Sec. Sec. 63.1216 and
63.1217--solid fuel-fired boilers, and those liquid fuel-fired boilers
that are not equipped with a dry particulate matter control device--you
must conduct a one-time emission test for dioxin/furan under feed and
operating conditions that are most likely to maximize dioxin/furan
emissions, similar to a dioxin/furan compliance test.
(i) You must conduct the dioxin/furan emissions test no later than
the deadline for conducting the initial comprehensive performance test.
(ii) You may use dioxin/furan emissions data from previous testing
to meet this requirement, provided that:
(A) The testing was conducted under feed and operating conditions
that are most likely to maximize dioxin/furan emissions, similar to a
dioxin/furan compliance test;
(B) You have not changed the design or operation of the boiler in a
manner that could significantly affect stack gas dioxin/furan emission
concentrations; and
(C) The data meet quality assurance objectives that may be
determined on a site-specific basis.
(iii) You may use dioxin/furan emissions data from a boiler to
represent emissions from another on-site boiler in lieu of testing
(i.e., data in lieu of testing) if the design and operation, including
fuels and hazardous waste feed, of the boilers are identical.
(iv) You must include the results of the one-time dioxin/furan
emissions test with the results of the initial comprehensive
performance test in the Notification of Compliance.
(v) You must repeat the dioxin/furan emissions test if you change
the design or operation of the source in a manner that may increase
dioxin/furan emissions.
(c) * * * (1) Test date. Except as provided by paragraphs (c)(2)
and (c)(3) of this section, you must commence the initial comprehensive
performance test not later than six months after the compliance date.
* * * * *
(3) For incinerators, cement kilns, and lightweight aggregate
kilns, you must commence the initial comprehensive performance test to
demonstrate compliance with the standards under Sec. Sec. 63.1219,
63.1220, and 63.1221 not later than 12 months after the compliance date.
* * * * *
(e) * * *
(2) After the Administrator has approved the site-specific test
plan and CMS performance evaluation test plan, but no later than 60
calendar days before initiation of the test, you must make the test
plans available to the public for review. You must issue a public
notice to all persons on your facility/public mailing list (developed
pursuant to 40 CFR 70.7(h), 71.11(d)(3)(i)(E) and 124.10(c)(1)(ix))
announcing the approval of the test plans and the location where the
test plans are available for review. The test plans must be accessible
to the public for 60 calendar days, beginning on the date that you
issue your public notice. The location must be unrestricted and provide
access to the public during reasonable hours and provide a means for
the public to obtain copies. The notification must include the
following information at a minimum:
(i) The name and telephone number of the source's contact person;
(ii) The name and telephone number of the regulatory agency's
contact person;
(iii) The location where the approved test plans and any necessary
supporting documentation can be reviewed and copied;
(iv) The time period for which the test plans will be available for
public review; and
(v) An expected time period for commencement and completion of the
performance test and CMS performance evaluation test.
(3) * * *
(iv) Public notice. At the same time that you submit your petition
to the Administrator, you must notify the public (e.g., distribute a
notice to the facility/public mailing list developed pursuant to 40 CFR
70.7(h), 71.11(d)(3)(i)(E) and 124.10(c)(1)(ix)) of your petition to
waive a performance test. The notification must include all of the
following information at a minimum:
(A) The name and telephone number of the source's contact person;
(B) The name and telephone number of the regulatory agency's
contact person;
(C) The date the source submitted its site-specific performance
test plan and CMS performance evaluation test plans; and
(D) The length of time requested for the waiver.
(f) * * *
(1) * * *
(ii) * * *
(D) The Administrator may approve on a case-by-case basis a
hazardous waste feedstream analysis for organic hazardous air
pollutants in lieu of the analysis required under paragraph
(f)(1)(ii)(A) of this section if the reduced analysis is sufficient to
ensure that the POHCs used to demonstrate compliance with the
applicable DRE standards of this subpart continue to be representative
of the organic hazardous air pollutants in your hazardous waste feedstreams;
* * * * *

[[Page 21366]]

(xiii) For cement kilns with in-line raw mills, if you elect to use
the emissions averaging provision of this subpart, you must notify the
Administrator of your intent in the initial (and subsequent)
comprehensive performance test plan, and provide the information
required by the emission averaging provision;
(xiv) For preheater or preheater/precalciner cement kilns with dual
stacks, if you elect to use the emissions averaging provision of this
subpart, you must notify the Administrator of your intent in the
initial (and subsequent) comprehensive performance test plan, and
provide the information required by the emission averaging provision;
(xv) If you request to use Method 23 for dioxin/furan you must
provide the information required under Sec. 63.1208(b)(1)(i)(B);
* * * * *
(j) * * * (1) * * *
(ii) Upon postmark of the Notification of Compliance, you must
comply with all operating requirements specified in the Notification of
Compliance in lieu of the limits specified in the Documentation of
Compliance required under Sec. 63.1211(d).
* * * * *
(3) See Sec. Sec. 63.7(g), 63.9(h), and 63.1210(d) for additional
requirements pertaining to the Notification of Compliance (e.g., you
must include results of performance tests in the Notification of Compliance).
* * * * *
(l) Failure of performance test--(1) Comprehensive performance
test. The provisions of this paragraph do not apply to the initial
comprehensive performance test if you conduct the test prior to your
compliance date.
* * * * *
6. Section 63.1208 is amended by revising paragraphs (b)(1)(i) and
(b)(5) to read as follows:

Sec. 63.1208 What are the test methods?

* * * * *
(b) * * *
(1) * * * (i) To determine compliance with the emission standard
for dioxins and furans, you must use:
(A) Method 0023A, Sampling Method for Polychlorinated Dibenzp-p-
Dioxins and Polychlorinated Dibenzofurans emissions from Stationary
Sources, EPA Publication SW-846, as incorporated by reference in
paragraph (a) of this section; or
(B) Method 23, provided in appendix A, part 60 of this chapter,
except that for coal-fired boilers, sources equipped with an activated
carbon injection system, and other sources that the Administrator
determines may emit carbonaceous particulate matter that may bias
Method 23 results, you may use Method 23 only upon the Administrator's
approval. In determining whether to grant approval to use Method 23,
the Administrator may consider factors including whether dioxin/furan
are detected at levels substantially below the emission standard, and
whether previous Method 0023 analyses detected low levels of dioxin/
furan in the front half.
* * * * *
(5) Hydrogen chloride and chlorine gas--(i) Compliance with MACT
standards. To determine compliance with the emission standard for
hydrogen chloride and chlorine gas (combined), you must use:
(A) Method 26/26A as provided in appendix A, part 60 of this chapter; or
(B) Methods 320 or 321 as provided in appendix A, part 60 of this
chapter, or ASTM D 6735-01, Test Method for Measurement of Gaseous
Chlorides and Fluorides from Mineral Calcining Exhaust Sources--
Impinger Method to measure emissions of hydrogen chloride, and Method
26/26A to measure emissions of chlorine gas.
(ii) Compliance with risk-based limits under Sec. 63.1215. To
demonstrate compliance with emission limits established under Sec.
63.1215, you must use Methods 26/26A, 320,or 321, or ASTM D 6735-01,
Test Method for Measurement of Gaseous Chlorides and Fluorides from
Mineral Calcining Exhaust Sources--Impinger Method, except:
(A) For cement kilns and sources equipped with a dry acid gas
scrubber, you must use Methods 320 or 321, or ASTM D 6735-01 to measure
hydrogen chloride, and the back-half, caustic impingers of Method 26/
26A to measure chlorine gas; and
(B) For incinerators, boilers, and lightweight aggregate kilns, you
must use Methods 320 or 321, or ASTM D 6735-01 to measure hydrogen
chloride, and Method 26/26A to measure total chlorine, and calculate
chlorine gas by difference if:
(1) The bromine/chlorine ratio in feedstreams is greater than 5 percent; or
(2) The sulfur/chlorine ratio in feedstreams is greater than 50
percent.
* * * * *
7. Section 63.1209 is amended by:
a. Revising paragraphs (a)(1)(ii)(A), (a)(1)(iv)(D), and (a)(1)(v)(D).
b. Revising paragraph (f)(1).
c. Revising the heading of paragraph (g)(1) introductory text and
paragraph (g)(1)(i).
d. Revising paragraphs (k)(1)(i) and (k)(2)(i).
e. Revising paragraph (l)(1).
f. Revising paragraph (m)(1)(iv) introductory text.
g. Revising paragraph (n)(2).
h. Revising paragraph (o)(1).
i. Revising paragraph (q)(1)(ii).
The revisions read as follows:

Sec. 63.1209 What are the monitoring requirements?

(a) * * * (1) * * *
(ii) * * *
(A) You must maintain and operate each COMS in accordance with the
requirements of Sec. 63.8(c) except for the requirements under Sec.
63.8(c)(3). The requirements of Sec. 63.1211(d) shall be complied with
instead of Sec. 63.8(c)(3); and
* * * * *
(iv) * * *
(D) To remain in compliance, all six-minute block averages must not
exceed the opacity standard.
(v) * * *
(D) To remain in compliance, all six-minute block averages must not
exceed the opacity standard.
* * * * *
(f) * * *
(1) Section 63.8(c)(3). The requirements of Sec. 63.1211(d), that
requires CMSs to be installed, calibrated, and operational on the
compliance date, shall be complied with instead of Sec. 63.8(c)(3).
* * * * *
(g) * * *
(1) Requests to use alternatives to operating parameter monitoring
requirements. (i) You may submit an application to the Administrator or
State with an approved Title V program under this paragraph for
approval of alternative operating parameter monitoring requirements to
document compliance with the emission standards of this subpart. For
requests to use additional CEMS, however, you must use paragraph (a)(5)
of this section and Sec. 63.8(f).
* * * * *
(k) * * *
(1) * * * (i) For sources other than a lightweight aggregate kiln,
if the combustor is equipped with an electrostatic precipitator,
baghouse (fabric filter), or other dry emissions control device where
particulate matter is suspended in contact with combustion gas, you
must establish a limit on the maximum temperature of the gas at the
inlet to the device on an hourly rolling average. You must establish
the hourly rolling average limit as the average of the test run averages.
* * * * *
(2) * * * (i) For sources other than cement kilns, you must measure the

[[Page 21367]]

temperature of each combustion chamber at a location that best
represents, as practicable, the bulk gas temperature in the combustion
zone. You must document the temperature measurement location in the
test plan you submit under Sec. Sec. 63.1207(e) and (f);
* * * * *
(l) * * *
(1) Feedrate of mercury. (i) For incinerators, cement kilns, and
lightweight aggregate kilns, when complying with the mercury emission
standards under Sec. Sec. 63.1203, 63.1204, and 63.1205, and for solid
fuel-fired boilers, you must establish a 12-hour rolling average limit
for the total feedrate of mercury in all feedstreams as the average of
the test run averages.
(ii) For incinerators, cement kilns, and lightweight aggregate
kilns, when complying with the mercury emission standards under
Sec. Sec. 63.1219, 63.1220, and 63.1221, you must establish an annual
rolling average limit for the total feedrate of mercury in all
feedstreams as follows:
(A) You must calculate a mercury system removal efficiency for each
test run as [1--mercury emission rate (g/s) / mercury feedrate (g/s)],
and calculate the average system removal efficiency of the test run
averages, except if your source is not equipped with a control system
that consistently and reproducibly controls mercury emissions, you must
assume zero system removal efficiency. If emissions exceed the mercury
emission standard, it is not a violation because compliance with these
mercury emission standards, which are derived from normal emissions
data, is based on compliance with the mercury feedrate limit on an
annual rolling average.
(B) You must calculate the annual average mercury feedrate limit as
the mercury emission standard ([mu]g/m \3\) divided by the system
removal efficiency. The feedrate limit is expressed as an emission
concentration, [mu]g mercury/m \3\ of stack gas.
(C) You must comply with the emission concentration-based annual
average mercury feedrate limit by measuring the mercury feedrate (g/s)
and the stack gas flowrate (m \3\/s) at least once a minute to
calculate a 60-minute average emission concentration-based feedrate as
[mercury feedrate (g/s) / gas flowrate (m \3\/s)].
(D) You must calculate an annual rolling average mercury feedrate
that is updated each hour.
(iii) For liquid fuel-fired boilers, you must establish an annual
rolling average hazardous waste mercury thermal concentration limit, as
follows:
(A) You must calculate a mercury system removal efficiency for each
test run as [1--mercury emission rate (g/s) / mercury feedrate (g/s)],
and calculate the average system removal efficiency of the test run
averages, except if your source is not equipped with a control system
that consistently and reproducibly controls mercury emissions, you must
assume zero system removal efficiency. If emissions exceed the mercury
emission standard, it is not a violation because compliance with the
mercury emission standard, which is derived from normal emissions data,
is based on compliance with the hazardous waste mercury thermal
concentration limit on an annual rolling average.
(B) You must calculate the annual average hazardous waste mercury
thermal concentration limit as the mercury emission standard (lb/MM
Btu) divided by the system removal efficiency. The hazardous waste
thermal concentration limit is expressed as: lb mercury in hazardous
waste feedstreams per million Btu of hazardous waste.
(C) You must comply with the annual average hazardous waste mercury
thermal concentration limit by measuring the feedrate of mercury in all
hazardous waste feedstreams (lb/s) and the hazardous waste thermal
feedrate (MM Btu/s) at least once a minute to calculate a 60-minute
average thermal emission concentration as [hazardous waste mercury
feedrate (g/s) / hazardous waste thermal feedrate (MM Btu/s)].
(D) You must calculate an annual rolling average hazardous waste
mercury thermal concentration that is updated each hour.
(iv) Extrapolation of feedrate levels. (A) In lieu of establishing
mercury feedrate limits as specified in paragraphs (l)(1)(i) through
(iii) of this section, you may request as part of the performance test
plan under Sec. Sec. 63.6(b) and (c) and Sec. Sec. 63.1207 (e) and
(f) to use the mercury feedrates and associated emission rates during
the comprehensive performance test to extrapolate to higher allowable
feedrate limits and emission rates. The extrapolation methodology will
be reviewed and approved, as warranted, by the Administrator. The
review will consider in particular whether:
(1) Performance test metal feedrates are appropriate (i.e., whether
feedrates are at least at normal levels; depending on the heterogeneity
of the waste, whether some level of spiking would be appropriate; and
whether the physical form and species of spiked material is appropriate); and
(2) Whether the extrapolated feedrates you request are warranted
considering historical metal feedrate data.
(B) The Administrator will review the performance test results in
making a finding of compliance required by Sec. Sec. 63.6(f)(3) and
63.1206(b)(3) to ensure that you have interpreted the performance test
results properly and the extrapolation procedure is appropriate for
your source.
* * * * *
(m) * * *
(1) * * *
(iv) Other particulate matter control devices. For each particulate
matter control device that is not a fabric filter or high energy wet
scrubber, or is not an electrostatic precipitator or ionizing wet
scrubber for which you elect to monitor particulate matter loadings
under Sec. 63.1206(c)(7)(iii) of this chapter for process control, you
must ensure that the control device is properly operated and maintained
as required by Sec. 63.1206(c)(7) and by monitoring the operation of
the control device as follows:
* * * * *
(n) * * *
(2) Maximum feedrate of semivolatile and low volatile metals--(i)
General. You must establish feedrate limits for semivolatile metals
(cadmium and lead) and low volatile metals (arsenic, beryllium, and
chromium) as follows, except as provided by paragraph (n)(2)(vii) of
this section.
(ii) For incinerators, cement kilns, and lightweight aggregate
kilns, when complying with the emission standards under Sec. Sec.
63.1203, 63.1204, 63.1205, and 63.1219 and for solid fuel-fired
boilers, you must establish 12-hour rolling average limits for the
total feedrate of semivolatile and low volatile metals in all
feedstreams as the average of the test run averages and as specified in
paragraph (n)(2)(iv) of this section.
(iii) For cement kilns, when complying with the emission standards
under Sec. 63.1220, you must establish 12-hour rolling average
feedrate limits for semivolatile and low volatile metals as the thermal
concentration of semivolatile metals or low volatile metals in all
hazardous waste feedstreams. You must calculate hazardous waste thermal
concentrations for semivolatile metals and low volatile metals for each
run as the total mass feedrate of semivolatile metals or low volatile
metals for all hazardous waste feedstreams divided by the total heat
input rate for all hazardous waste feedstreams. The 12-hour rolling
average feedrate limits for semivolatile metals and low volatile metals
are the

[[Page 21368]]

average of the hazardous waste thermal concentrations for the runs.
(iv) Lightweight aggregate kilns under Sec. 63.1221--(A) Existing
sources. When complying with the emission standards under Sec.
63.1221, you must establish semivolatile metal and low volatile metal
feedrate limits as 12-hour rolling average feedrate limits and 12-hour
rolling average hazardous waste thermal concentrations as specified in
paragraphs (n)(2)(ii) and (iii). You must comply with both feedrate
limits for semivolatile metals and low volatile metals.
(B) New sources. When complying with the emission standards under
Sec. 63.1221, you must establish semivolatile metal and low volatile
metal feedrate limits as 12-hour rolling average hazardous waste
thermal concentrations as specified in paragraphs (n)(2)(ii) and (iii).
(v) Liquid fuel-fired boilers. (A) For semivolatile metals, you
must establish an annual rolling average hazardous waste thermal
concentration limit, as follows:
(1) You must calculate a semivolatile metals system removal
efficiency for each test run as [1--semivolatile metals emission rate
(g/s) / semivolatile metals feedrate (g/s)], and calculate the average
system removal efficiency of the test run averages, except if your
source is not equipped with a control system that consistently and
reproducibly controls semivolatile metals emissions, you must assume
zero system removal efficiency. If emissions exceed the semivolatile
metals emission standard, it is not a violation because compliance with
the semivolatile metals emission standard, which is derived from normal
emissions data, is based on compliance with the semivolatile metals
hazardous waste thermal concentration limit on an annual rolling
average.
(2) You must calculate the annual average hazardous waste
semivolatile metals thermal concentration limit as the semivolatile
metals emission standard (lb/MM Btu) divided by the system removal
efficiency. The hazardous waste thermal concentration limit is
expressed as: pounds semivolatile metals in hazardous waste feedstreams
per million Btu of hazardous waste.
(3) You must comply with the annual average hazardous waste
semivolatile metals thermal concentration limit by measuring the
feedrate of semivolatile metals in all hazardous waste feedstreams (lb/
s) and the hazardous waste thermal feedrate (MM Btu/s) at least once a
minute to calculate a 60-minute average thermal emission concentration
as [hazardous waste semivolatile metals feedrate (g/s) / hazardous
waste thermal feedrate (MM Btu/s)].
(4) You must calculate an annual rolling average hazardous waste
semivolatile metals thermal concentration that is updated each hour.
(B) For low volatile metals, you must establish 12-hour rolling
average feedrate limits for chromium as the thermal concentration of
chromium in all hazardous waste feedstreams. You must calculate a
hazardous waste thermal concentration for chromium for each run as the
total mass feedrate of chromium for all hazardous waste feedstreams
divided by the total heat input rate for all hazardous waste
feedstreams. The 12-hour rolling average feedrate limit for chromium is
the average of the hazardous waste thermal concentrations for the runs.
(vi) LVM limits for pumpable wastes. You must establish separate
feedrate limits for low volatile metals in pumpable feedstreams using
the procedures prescribed above for total low volatile metals. Dual
feedrate limits for both pumpable and total feedstreams are not
required, however, if you base the total feedrate limit solely on the
feedrate of pumpable feedstreams.
(vii) Extrapolation of feedrate levels. In lieu of establishing
feedrate limits as specified in paragraphs (l)(1)(i) through (iii) of
this section, you may request as part of the performance test plan
under Sec. Sec. 63.6(b) and (c) and 63.1207(e) and (f) to use the
semivolatile metal and low volatile metal feedrates and associated
emission rates during the comprehensive performance test to extrapolate
to higher allowable feedrate limits and emission rates. The
extrapolation methodology will be reviewed and approved, as warranted,
by the Administrator. The review will consider in particular whether:
(A) Performance test metal feedrates are appropriate (i.e., whether
feedrates are at least at normal levels; depending on the heterogeneity
of the waste, whether some level of spiking would be appropriate; and
whether the physical form and species of spiked material is appropriate);
(B) Whether the extrapolated feedrates you request are warranted
considering historical metal feedrate data; and
(C) Whether you have interpreted the performance test results
properly and the extrapolation procedure is appropriate for your source.
* * * * *
(o) * * *
(1) Feedrate of total chlorine and chloride--(i) Incinerators,
cement kilns, lightweight aggregate kilns, solid fuel-fired boilers,
and hydrochloric acid production furnaces. You must establish 12-hour
rolling average limit for the total feedrate of chlorine (organic and
inorganic) in all feedstreams as the average of the test run averages.
(ii) Liquid fuel-fired boilers. You must establish a 12-hour
rolling average limit for the feedrate of chlorine (organic and
inorganic) as the thermal concentration of chlorine in all hazardous
waste feedstreams. You must calculate a hazardous waste thermal
concentration for chlorine for each run as the total mass feedrate of
chlorine for all hazardous waste feedstreams divided by the total heat
input rate for all hazardous waste feedstreams. The 12-hour rolling
average feedrate limit chlorine is the average of the hazardous waste
thermal concentrations for the runs.
* * * * *
(q) * * *
(1) * * *
(ii) You must specify (e.g., by reference) the otherwise applicable
requirements as a mode of operation in your Documentation of Compliance
under Sec. 63.1211(d), your Notification of Compliance under Sec.
63.1207(j), and your title V permit application. These requirements
include the otherwise applicable requirements governing emission
standards, monitoring and compliance, and notification, reporting, and
recordkeeping.
* * * * *
8. Section 63.1210 is amended by:
a. Revising the table in paragraph (a)(1) and the table in
paragraph (a)(2).
b. Redesignating paragraph (b) as (d).
c. Adding new paragraph (b).
d. Adding new paragraph (c).
The revisions and additions read as follows:

Sec. 63.1210 What are the notification requirements?

(a) * * *
(1) * * *

------------------------------------------------------------------------
Reference Notification
------------------------------------------------------------------------
63.9(b)........................... Initial notifications that you are
subject to subpart EEE of this
part.
63.9(d)........................... Notification that you are subject to
special compliance requirements.

[[Page 21369]]

63.9(j)........................... Notification and documentation of
any change in information already
provided under Sec. 63.9.
63.1206(b)(5)(i).................. Notification of changes in design,
operation, or maintenance.
63.1206(c)(7)(ii)(C).............. Notification of excessive bag leak
detection system exceedances.
63.1207(e), 63.9(e), 63.9(g)(1) Notification of performance test and
and (3). continuous monitoring system
evaluation, including the
performance test plan and CMS
performance evaluation plan.\1\
63.1210(d), 63.1207(j), Notification of compliance,
63.1207(k), 63.1207(l), 63.9(h), including results of performance
63.10(d)(2), 63.10(e)(2). tests and continuous monitoring
system performance evaluations.
------------------------------------------------------------------------
\1\ You may also be required on a case-by-case basis to submit a
feedstream analysis plan under Sec. 63.1209(c)(3).

(2) * * *

------------------------------------------------------------------------
Notification, request, petition, or
Reference application
------------------------------------------------------------------------
63.9(i)........................... You may request an adjustment to
time periods or postmark deadlines
for submittal and review of
required information.
63.10(e)(3)(ii)................... You may request to reduce the
frequency of excess emissions and
CMS performance reports.
63.10(f).......................... You may request to waive
recordkeeping or reporting
requirements.
63.1204(d)(2)(iii), Notification that you elect to
63.1220(d)(2)(iii). comply with the emission averaging
requirements for cement kilns with
in-line raw mills.
63.1204(e)(2)(iii), Notification that you elect to
63.1220(e)(2)(iii). comply with the emission averaging
requirements for preheater or
preheater/precalciner kilns with
dual stacks.
63.1206(b)(4), 63.1213, 63.6(i), You may request an extension of the
63.9(c). compliance date for up to one year.
63.1206(b)(5)(i)(C)............... You may request to burn hazardous
waste for more than 720 hours and
for purposes other than testing or
pretesting after a making a change
in the design or operation that
could affect compliance with
emission standards and prior to
submitting a revised Notification
of Compliance.
63.1206(b)(8)(iii)(B)............. If you elect to conduct particulate
matter CEMS correlation testing and
wish to have federal particulate
matter and opacity standards and
associated operating limits waived
during the testing, you must notify
the Administrator by submitting the
correlation test plan for review
and approval.
63.1206(b)(8)(v).................. You may request approval to have the
particulate matter and opacity
standards and associated operating
limits and conditions waived for
more than 96 hours for a
correlation test.
63.1206(b)(9)..................... Owners and operators of lightweight
aggregate kilns may request
approval of alternative emission
standards for mercury, semivolatile
metal, low volatile metal, and
hydrochloric acid/chlorine gas
under certain conditions.
63.1206(b)(10).................... Owners and operators of cement kilns
may request approval of alternative
emission standards for mercury,
semivolatile metal, low volatile
metal, and hydrochloric acid/
chlorine gas under certain
conditions.
63.1206(b)(14).................... Owners and operators of incinerators
may elect to comply with an
alternative to the particulate
matter standard.
63.1206(b)(15).................... Owners and operators of cement and
lightweight aggregate kilns may
request to comply with the
alternative to the interim
standards for mercury.
63.1206(c)(2)(ii)(C).............. You may request to make changes to
the startup, shutdown, and
malfunction plan.
63.1206(c)(5)(i)(C)............... You may request an alternative means
of control to provide control of
combustion system leaks.
63.1206(c)(5)(i)(D)............... You may request other techniques to
prevent fugitive emissions without
use of instantaneous pressure
limits.
63.1207(c)(2)..................... You may request to base initial
compliance on data in lieu of a
comprehensive performance test.
63.1207(d)(3)..................... You may request more than 60 days to
complete a performance test if
additional time is needed for
reasons beyond your control.
63.1207(e)(3), 63.7(h)............ You may request a time extension if
the Administrator fails to approve
or deny your test plan.
63.1207(h)(2)..................... You may request to waive current
operating parameter limits during
pretesting for more than 720 hours.
63.1207(f)(1)(ii)(D).............. You may request a reduced hazardous
waste feedstream analysis for
organic hazardous air pollutants if
the reduced analysis continues to
be representative of organic
hazardous air pollutants in your
hazardous waste feedstreams.
63.1207(g)(2)(v).................. You may request to operate under a
wider operating range for a
parameter during confirmatory
performance testing.
63.1207(i)........................ You may request up to a one-year
time extension for conducting a
performance test (other than the
initial comprehensive performance
test) to consolidate testing with
other state or federally-required
testing.
63.1207(j)(4)..................... You may request more than 90 days to
submit a Notification of Compliance
after completing a performance test
if additional time is needed for
reasons beyond your control.
63.1207(l)(3)..................... After failure of a performance test,
you may request to burn hazardous
waste for more than 720 hours and
for purposes other than testing or
pretesting.
63.1209(a)(5), 63.8(f)............ You may request: (1) Approval of
alternative monitoring methods for
compliance with standards that are
monitored with a CEMS; and (2)
approval to use a CEMS in lieu of
operating parameter limits.
63.1209(g)(1)..................... You may request approval of: (1)
Alternatives to operating parameter
monitoring requirements, except for
standards that you must monitor
with a continuous emission
monitoring system (CEMS) and except
for requests to use a CEMS in lieu
of operating parameter limits; or
(2) a waiver of an operating
parameter limit.
63.1209(l)(1)..................... You may request to extrapolate
mercury feedrate limits.
63.1209(n)(2)..................... You may request to extrapolate
semivolatile and low volatile metal
feedrate limits.
63.1211(e)........................ You may request to use data
compression techniques to record
data on a less frequent basis than
required by Sec. 63.1209.
------------------------------------------------------------------------

[[Page 21370]]

(b) Notification of intent to comply (NIC). (1) You must prepare a
Notification of Intent to Comply that includes all of the following
information:
(i) General information:
(A) The name and address of the owner/operator and the source;
(B) Whether the source is a major or an area source;
(C) Waste minimization and emission control technique(s) being considered;
(D) Emission monitoring technique(s) you are considering;
(E) Waste minimization and emission control technique(s) effectiveness;
(F) A description of the evaluation criteria used or to be used to
select waste minimization and/or emission control technique(s); and
(G) A general description of how you intend to comply with the
emission standards of this subpart.
(ii) As applicable to each source, information on key activities
and estimated dates for these activities that will bring the source
into compliance with emission control requirements of this subpart. You
must include all of the following key activities and dates in your NIC:
(A) The dates by which you will develop engineering designs for
emission control systems or process changes for emissions;
(B) The date by which you will commit internal or external
resources for installing emission control systems or making process
changes for emission control, or the date by which you will issue
orders for the purchase of component parts to accomplish emission
control or process changes.
(C) The date by which you will submit construction applications;
(D) The date by which you will initiate on-site construction,
installation of emission control equipment, or process change;
(E) The date by which you will complete on-site construction,
installation of emission control equipment, or process change; and
(F) The date by which you will achieve final compliance. The
individual dates and milestones listed in paragraphs (b)(1)(ii)(A)
through (F) of this section as part of the NIC are not requirements and
therefore are not enforceable deadlines; the requirements of paragraphs
(b)(1)(ii)(A) through (F) of this section must be included as part of
the NIC only to inform the public of your how you intend to comply with
the emission standards of this subpart.
(iii) A summary of the public meeting required under paragraph (c)
of this section;
(iv) If you intend to cease burning hazardous waste prior to or on
the compliance date, you must include in your NIC a schedule of key
dates for the steps to be taken to stop hazardous waste activity at
your combustion unit. Key dates include the date for submittal of RCRA
closure documents required under subpart G, part 264 of this chapter.
(2) You must make a draft of the NIC available for public review no
later than 30 days prior to the public meeting required under paragraph
(c)(1) of this section.
(3) You must submit the final NIC to the Administrator no later
than one year following the effective date of the emission standards of
this subpart.
(c) NIC public meeting and notice. (1) Prior to the submission of
the NIC to the permitting agency, and no later than 10 months after the
effective date of the emission standards of this subpart, you must hold
at least one informal meeting with the public to discuss anticipated
activities described in the draft NIC for achieving compliance with the
emission standards of this subpart. You must post a sign-in sheet or
otherwise provide a voluntary opportunity for attendees to provide
their names and addresses;
(2) You must submit a summary of the meeting, along with the list
of attendees and their addresses developed under paragraph (b)(1) of
this section, and copies of any written comments or materials submitted
at the meeting, to the Administrator as part of the final NIC, in
accordance with paragraph (b)(1)(iii) of this section;
(3) You must provide public notice of the NIC meeting at least 30
days prior to the meeting. You must provide public notice in all of the
following forms:
(i) Newspaper advertisement. You must publish a notice in a
newspaper of general circulation in the county or equivalent
jurisdiction of your facility. In addition, you must publish the notice
in newspapers of general circulation in adjacent counties or equivalent
jurisdiction where such publication would be necessary to inform the
affected public. You must publish the notice as a display advertisement.
(ii) Visible and accessible sign. You must post a notice on a
clearly marked sign at or near the source. If you place the sign on the
site of the hazardous waste combustor, the sign must be large enough to
be readable from the nearest spot where the public would pass by the site.
(iii) Broadcast media announcement. You must broadcast a notice at
least once on at least one local radio station or television station.
(iv) Notice to the facility mailing list. You must provide a copy
of the notice to the facility mailing list in accordance with Sec.
124.10(c)(1)(ix) of this chapter.
(4) You must include all of the following in the notices required
under paragraph (c)(3) of this section:
(i) The date, time, and location of the meeting;
(ii) A brief description of the purpose of the meeting;
(iii) A brief description of the source and proposed operations,
including the address or a map (e.g., a sketched or copied street map)
of the source location;
(iv) A statement encouraging people to contact the source at least
72 hours before the meeting if they need special access to participate
in the meeting;
(v) A statement describing how the draft NIC (and final NIC, if
requested) can be obtained; and
(vi) The name, address, and telephone number of a contact person
for the NIC.
9. Section 63.1211 is amended by:
a. Revising the table in paragraph (b).
b. Redesignating paragraphs (c) and (d) as (d) and (e).
c. Adding new paragraph (c).
The revisions and additions read as follows:

Sec. 63.1211 What are the recordkeeping and reporting requirements?

* * * * *
(b) * * *

------------------------------------------------------------------------
Reference Document, data, or information
------------------------------------------------------------------------
63.1200, 53.10 (b) and (c)........ General. Information required to
document and maintain compliance
with the regulations of subpart
EEE, including data recorded by
continuous monitoring systems
(CMS), and copies of all
notifications, reports, plans, and
other documents submitted to the
Administrator.
63.1204(d)(1)(ii), Documentation of mode of operation
63.1220(d)(1)(ii). changes for cement kilns with in-
line raw mills.
63.1204(d)(2)(ii), Documentation of compliance with the
63.1220(d)(2)(ii). emission averaging requirements for
cement kilns with in-line raw
mills.
63.1204(e)(2)(ii), Documentation of compliance with the
63.1220(e)(2)(ii). emission averaging requirements for
preheater or preheater/precalciner
kilns with dual stacks.

[[Page 21371]]

63.1206(b)(1)(ii)................. If you elect to comply with all
applicable requirements and
standards promulgated under
authority of the Clean Air Act,
including sections 112 and 129, in
lieu of the requirements of subpart
EEE when not burning hazardous
waste, you must document in the
operating record that you are in
compliance with those requirements.
63.1206(b)(5)(ii)................. Documentation that a change will not
adversely affect compliance with
the emission standards or operating
requirements.
63.1206(b)(11).................... Calculation of hazardous waste
residence time.
63.1206(c)(2)..................... Startup, shutdown, and malfunction
plan.
63.1206(c)(2)(v)(A)............... Documentation of your investigation
and evaluation of excessive
exceedances during malfunctions.
63.1206(c)(3)(v).................. Corrective measures for any
automatic waste feed cutoff that
results in an exceedance of an
emission standard or operating
parameter limit.
63.1206(c)(3)(vii)................ Documentation and results of the
automatic waste feed cutoff
operability testing.
63.1206(c)(4)(ii)................. Emergency safety vent operating
plan.
63.1206(c)(4)(iii)................ Corrective measures for any
emergency safety vent opening.
63.1206(c)(5)(ii)................. Method used for control of
combustion system leaks.
63.1206(c)(6)..................... Operator training and certification
program.
63.1206(c)(7)(i)(D)............... Operation and maintenance plan.
63.1209(c)(2)..................... Feedstream analysis plan.
63.1209(k)(6)(iii), Documentation that a substitute
63.1209(k)(7)(ii), activated carbon, dioxin/furan
63.1209(k)(9)(ii), formation reaction inhibitor, or
63.1209(o)(4)(iii). dry scrubber sorbent will provide
the same level of control as the
original material.
63.1209(k)(7)(i)(C)............... Results of carbon bed performance
monitoring.
63.1209(q)........................ Documentation of changes in modes of
operation.
63.1211(d)........................ Documentation of compliance.
------------------------------------------------------------------------

(c) Compliance progress reports associated with the notification of
intent to comply--(1) General. Not later than two years following the
effective date of the emission standards of this subpart, you must
comply with the following, unless you comply with paragraph (c)(2)(ii)
of this section:
(i) Develop engineering design for any physical modifications to
the source needed to comply with the emission standards of this subpart;
(ii) Submit applicable construction applications to the Administrator; and
(iii) Document an internal or external commitment of resources,
i.e., funds or personnel, to purchase, fabricate, and install any
equipment, devices, and ancillary structures needed to comply with the
emission standards and operating requirements of this subpart.
(2) Progress report. (i) You must submit to the Administrator a
progress report not later than two years following the effective date
of the emission standards of this subpart, which contains information
documenting that you have met the requirements of paragraph (c)(1) of
this section and updates the information you previously provided in
your NIC. This information will be used by the Administrator to
determine if you have made adequate progress towards compliance with
the emission standards of this subpart. In any evaluation of adequate
progress, the Administrator may consider any delays in a source's
progress caused by the time required to obtain necessary permits (e.g.,
operating and construction permits or licenses) from governmental
regulatory agencies when the sources have submitted timely and complete
permit applications.
(ii) If you can comply with the emission standards and operating
requirements of this subpart, without undertaking any of the activities
described in paragraph (c)(1) of this section, you must submit a
progress report documenting either:
(A) That you, at the time of the progress report, are in compliance
with the emission standards and operating requirements; or
(B) The steps you will take to comply, without undertaking any of
the activities listed in paragraphs (c)(1)(i) through (c)(1)(iii) of
this section.
(3) Schedule. (i) You must include in the progress report a
detailed schedule that lists key dates for all projects that will bring
the source into compliance with the emission standards and operating
requirements of this subpart for the time period between submission of
the progress report and the compliance date of the emission standards
and operating requirements of this subpart.
(ii) The schedule must contain anticipated or actual dates for all
of the following:
(A) Bid and award dates, as necessary, for construction contracts
and equipment supply contractors;
(B) Milestones such as ground breaking, completion of drawings and
specifications, equipment deliveries, intermediate construction
completions, and testing;
(C) The dates on which applications will be submitted for operating
and construction permits or licenses;
(D) The dates by which approvals of any operating and construction
permits or licenses are anticipated; and
(E) The projected date by which you expect to comply with the
emission standards and operating requirements of this subpart.
(4) Sources that intend to cease burning hazardous waste prior to
or on the compliance date. (i) If you indicated in your NIC your intent
to cease burning hazardous waste and do so prior to submitting a
progress report, you are exempt from the requirements of paragraphs
(c)(1) through (c)(3) of this section. However, you must submit and
include in your progress report the date on which you stopped burning
hazardous waste and the date(s) you submitted, or plan to submit RCRA
closure documents.
(ii) If you signify in the progress report, submitted not later
than two years following the effective date of the emission standards
of this subpart, your intention to cease burning hazardous waste, you
must stop burning hazardous waste on or before the compliance date of
the emission standards of this subpart.
* * * * *
10. Section 63.1212 is added to subpart EEE to read as follows:

Sec. 63.1212 What are the other requirements pertaining to the NIC
and associated progress report?

(a) Certification of intent to comply. (1) The Notice of Intent to
Comply (NIC) and Progress Report must contain the following
certification signed and dated by an authorized representative of the
source: ``I certify under penalty of law that I have personally
examined and am

[[Page 21372]]

familiar with the information submitted in this document and all
attachments and that, based on my inquiry of those individuals
immediately responsible for obtaining the information, I believe that
the information is true, accurate, and complete. I am aware that there
are significant penalties for submitting false information, including
the possibility of fine and imprisonment''.
(2) An authorized representative should be a responsible corporate
officer (for a corporation), a general partner (for a partnership), the
proprietor (of a sole proprietorship), or a principal executive officer
or ranking elected official (for a municipality, State, Federal, or
other public agency).
(b) Sources that begin burning hazardous waste after the effective
date of the emission standards of this subpart. (1) If you begin to
burn hazardous waste after the effective date of the emission standards
of this subpart, but prior to nine months after the effective date of
the emission standards of this subpart, you must comply with the
requirements of Sec. Sec. 63.1206(a)(2), 63.1210(b) and (c),
63.1211(c), and paragraph (a) of this section, and associated time
frames for public meetings and document submittals.
(2) If you intend to begin burning hazardous waste more than nine
months after the effective date of the emission standards of this
subpart, you must comply with the requirements of Sec. Sec.
63.1206(a)(2), 63.1210(b) and (c), 63.1211(c), and paragraph (a) of
this section prior to burning hazardous waste. In addition:
(i) You must make a draft NIC available to the public, notice the
public meeting, conduct a public meeting, and submit a final NIC prior
to burning hazardous waste; and
(ii) You must submit your progress report at the time you submit
your final NIC.
11. Section 63.1214 is amended by revising paragraphs (c)(1),
(c)(2), (c)(3), and (c)(4) to read as follows:

Sec. 63.1214 Implementation and enforcement.

* * * * *
(c) * * *
(1) Approval of alternatives to requirements in Sec. Sec. 63.1200,
63.1203, 63.1204, 63.1205, 63.1206(a), 63.1215, 63.1216, 63.1217,
63.1218, 63.1219, 63.1220, and 63.1221.
(2) Approval of major alternatives to test methods under Sec. Sec.
63.7(e)(2)(ii) and (f), 63.1208(b), and 63.1209(a)(1), as defined in
Sec. 63.90, and as required in this subpart.
(3) Approval of major alternatives to monitoring under Sec. Sec.
63.8(f) and 63.1209(a)(5), as defined in Sec. 63.90, and as required
in this subpart.
(4) Approval of major alternatives to recordkeeping and reporting
under Sec. Sec. 63.10(f) and 63.1211(a) through (d), as defined in
Sec. 63.90, and as required in this subpart.
12. Section Sec. 63.1215 is added to subpart EEE to read as follows:

Sec. 63.1215 What are the alternative risk-based standards for total
chlorine?

(a) General. You may establish and comply with site-specific, risk-
based emission limits for total chlorine under the procedures
prescribed in this section. You may comply with these risk-based
emission limits in lieu of the emission standards for total chlorine
provided under Sec. Sec. 63.1216, 63.1217, 63.1219, 63.1220, and
63.1221 of this chapter after review and approval by the permitting
authority. To identify and comply with the limits, you must:
(1) Identify hydrogen chloride and chlorine gas emission rates for
each on-site hazardous waste combustor. You may select hydrogen
chloride and chlorine gas emission rates as you choose to demonstrate
eligibility for the total chlorine standards under this section, except
as provided by paragraph (b)(4) of this section;
(2) Perform an eligibility demonstration to determine if your HCl-
equivalent emission rate limits meet the national exposure standards,
as prescribed by paragraphs (b) and (c) of this section;
(3) Submit your eligibility demonstration for review and approval,
as prescribed by paragraph (d) of this section;
(4) Demonstrate compliance with the HCl-equivalent emission rate
limits, as prescribed by the testing and monitoring requirements under
paragraph (e) of this section; and
(5) Comply with the requirements for changes, as prescribed by
paragraph (f) of this section.
(b) HCl-equivalent emission rates. (1) You must establish a total
chlorine limit for each hazardous waste combustor as an HCl-equivalent
emission rate.
(2) You must calculate the toxicity-weighted HCl-equivalent
emission rate for each combustor as follows:

ERtw = [sum](ERi x (RfCHCl/
RfCi))

Where:

ERtw is the HCl-equivalent emission rate, lb/hr
ERi is the emission rate of HAP i in lbs/hr
RfCi is the reference concentration of HAP i
RfCHCl is the reference concentration of HCl

(3) You must use the RfC values for hydrogen chloride and chlorine
gas found at http://epa.gov/ttn/atw/toxsource/sumnmary.html.
(4) The hydrogen chloride and chlorine gas emission rates you use
to calculate the HCl-equivalent emission rate limit for incinerators,
cement kilns, and lightweight aggregate kilns must not result in total
chlorine emission concentrations exceeding the standards provided by
Sec. Sec. 63.1203, 63.1204, and 63.1205.
(c) Eligibility demonstration--(1) General. You must perform an
eligibility demonstration to determine whether your selected hydrogen
chloride and chlorine gas emission rates meet the national exposure
standards using either a look-up table analysis prescribed by paragraph
(c)(3) of this section, or a site-specific compliance demonstration
prescribed by paragraph (c)(4) of this section.
(2) Definition of eligibility. Your facility is eligible for the
alternative risk-based standards for total chlorine if either:
(i) The sum of the calculated HCl-equivalent emission rates for all
on-site hazardous waste combustors is below the appropriate value in
the look-up table; or
(ii) Your site-specific compliance demonstration indicates that
your maximum Hazard Index for hydrogen chloride and chlorine gas
emissions from all on-site hazardous waste combustors at a location
where people live is less than or equal to 1.0, rounded to the nearest
tenths decimal place (0.1).
(3) Look-up table analysis. (i) The look-up table is provided as
Table 1 to this section.
(ii) To determine the correct HCl-equivalent emission rate value
from the look-up table, you must use the average stack height for your
hazardous waste combustors (i.e., the mean of the stack height of all
on-site hazardous waste combustors) and the minimum distance between
any hazardous waste combustor stack and the property boundary.
(iii) If one or both of these values for stack height and distance
to nearest property boundary do not match the exact values in the look-
up table, you would use the next lowest table value.
(iv) You are not eligible for the look-up table analysis if your
facility is located in complex terrain.
(v) If the sum of the calculated HCl-equivalent emission rates for
all on-site hazardous waste combustors is below the appropriate value
in the look-up

[[Page 21373]]

table, the emission limit for total chlorine for each combustor is the
HCl-equivalent emission rate you calculated.
(4) Site-specific compliance demonstration. (i) You may use any
scientifically-accepted peer-reviewed risk assessment methodology for
your site-specific compliance demonstration. An example of one approach
for performing the demonstration for air toxics can be found in the
EPA's ``Air Toxics Risk Assessment Reference Library, Volume 2, Site-
Specific Risk Assessment Technical Resource Document,'' which may be
obtained through the EPA's Air Toxics Web site at http://www.epa.gov/ttn/atw.

(ii) Your facility is eligible for the alternative risk-based total
chlorine emission limit if your site-specific compliance demonstration
shows that the maximum Hazard Index for hydrogen chloride and chlorine
gas emissions from each on-site hazardous waste combustor is less than
or equal to 1.0 rounded to the nearest tenths decimal place (0.1).
(iii) At a minimum, your site-specific compliance demonstration must:
(A) Estimate long-term inhalation exposures through the estimation
of annual or multi-year average ambient concentrations;
(B) Estimate the inhalation exposure for the actual individual most
exposed to the facility's emissions from hazardous waste combustors;
(C) Use site-specific, quality-assured data wherever possible;
(D) Use health-protective default assumptions wherever site-
specific data are not available, and:
(E) Contain adequate documentation of the data and methods used for
the assessment so that it is transparent and can be reproduced by an
experienced risk assessor and emissions measurement expert.
(iv) Your site-specific compliance demonstration need not:
(A) Assume any attenuation of exposure concentrations due to the
penetration of outdoor pollutants into indoor exposure areas;
(B) Assume any reaction or deposition of the emitted pollutants
during transport from the emission point to the point of exposure.
(v) If your site-specific compliance demonstration documents that
the maximum Hazard Index for hydrogen chloride and chlorine gas
emissions from your hazardous waste combustors is less than or equal to
1.0, you would establish a maximum HCl-equivalent emission rate limit
for each combustor based on the hydrogen chloride and chlorine gas
emission rates used in this site-specific compliance demonstration.
(d) Review and approval of eligibility demonstrations--(1) Content
of the eligibility demonstration--(i) General. The eligibility
demonstration must include the following information, at a minimum:
(A) Identification of each hazardous waste combustor combustion gas
emission point (e.g., generally, the flue gas stack);
(B) The maximum capacity at which each combustor will operate, and
the maximum rated capacity for each combustor, using the metric of
stack gas volume emitted per unit of time, as well as any other metric
that is appropriate for the combustor (e.g., million Btu/hr heat input
for boilers; tons of dry raw material feed/hour for cement kilns);
(C) Stack parameters for each combustor, including, but not limited
to stack height, stack area, stack gas temperature, and stack gas exit
velocity;
(D) Plot plan showing all stack emission points, nearby residences,
and property boundary line;
(E) Identification of any stack gas control devices used to reduce
emissions from each combustor;
(F) Identification of the RfC values used to calculate the HCl-
equivalent emissions rate;
(G) Calculations used to determine the HCl-equivalent emission rate;
(H) For incinerators, cement kilns, and lightweight aggregate
kilns, calculations used to determine that the HCl-equivalent emission
rate limit for each combustor does not exceed the standards for total
chlorine at Sec. Sec. 63.1203, 63.1204, and 63.1205; and
(I) The HCl-equivalent emission rate limit for each hazardous waste
combustor that you will certify in the Documentation of Compliance
required under Sec. 63.1211(d) that you will not exceed, and the
limits on the operating parameters specified under Sec. 63.1209(o)
that you will establish in the Documentation of Compliance.
(ii) Additional content of look-up table demonstration. If you use
the look-up table analysis, your eligibility demonstration must also
contain, at a minimum, the following:
(A) Calculations used to determine the average stack height of on-
site hazardous waste combustors;
(B) Identification of the combustor stack with the minimum distance
to the property boundary of the facility; and
(C) Comparison of the values in the look-up table to your maximum
HCl-equivalent emission rate.
(iii) Additional content of a site-specific compliance
demonstration. If you use a site-specific compliance demonstration,
your eligibility demonstration must also contain, at a minimum, the
following:
(A) Identification of the risk assessment methodology used;
(B) Documentation of the fate and transport model used;
(C) Documentation of the fate and transport model inputs, including
the stack parameters listed in paragraph (d)(1)(i)(C) of this section
converted to the dimensions required for the model;
(D) As applicable:
(1) Meteorological data;
(2) Building, land use, and terrain data;
(3) Receptor locations and population data; and
(4) Other facility-specific parameters input into the model;
(E) Documentation of the fate and transport model outputs;
(F) Documentation of any exposure assessment and risk
characterization calculations; and,
(G) Documentation of the predicted Hazard Index for HCl-equivalents
and comparison to the limit of less than 1.0.
(2) Review and approval--(i) Existing sources. (A) If you operate
an existing source, you must be in compliance with the emission
standards on the compliance date. If you elect to comply with the
alternative risk-based emission rate limit for total chlorine, you must
have completed the eligibility demonstration and received approval from
your delegated permitting authority by the compliance date.
(B) You must submit the eligibility demonstration to your
permitting authority for review and approval not later than 12 months
prior to the compliance date. You must submit a separate copy of the
eligibility demonstration to: U.S. EPA, Risk and Exposure Assessment
Group, Emission Standards Division (C404-01), Attn: Group Leader,
Research Triangle Park, North Carolina 27711.
(C) Your permitting authority will notify you of approval or intent
to disapprove your eligibility demonstration within 6 months after
receipt of the original demonstration, and within 3 months after
receipt of any supplemental information that you submit. A notice of
intent to disapprove your eligibility demonstration will identify
incomplete or inaccurate information or noncompliance with prescribed
procedures and specify how much time you will have to submit additional
information.
(D) If your permitting authority has not approved your eligibility
demonstration to comply with a risk-based HCl-equivalent emission
rate(s) by the compliance date, you must comply with the MACT emission

[[Page 21374]]

standards for total chlorine gas under Sec. Sec. 63.1216, 63.1217,
63.1219, 63.1220, and 63.1221 of this chapter.
(ii) New sources. General. (A) If you operate a source that is not
an existing source and that becomes subject to subpart EEE, you must
comply with the MACT emission standards for total chlorine unless and
until your eligibility demonstration has been approved by the
permitting authority.
(B) If you operate a new or reconstructed source that starts up
before the effective date of the emission standards proposed today, or
a solid fuel-fired boiler or liquid fuel-fired boiler that is an area
source that increases its emissions or its potential to emit such that
it becomes a major source of HAP before the effective date of
Sec. Sec. 63.1216 and 63.1217, you would be required to comply with
the emission standards under Sec. Sec. 63.1216 and 63.1217 until your
eligibility demonstration is approved by your permitting authority.
(C) If you operate a new or reconstructed source that starts up
after the effective date of the emission standards proposed today, or a
solid fuel-fired boiler or liquid fuel-fired boiler that is an area
source that increases its emissions or its potential to emit such that
it becomes a major source of HAP after the effective date of Sec. Sec.
63.1216 and 63.1217, you would be required to comply with the emission
standards under Sec. Sec. 63.1216 and 63.1217 until your eligibility
demonstration is approved by your permitting authority.
(e) Testing and monitoring requirements--(1) General. You must
document compliance during the comprehensive performance test under
Sec. 63.1207 with the HCl-equivalent emission rate limit established
in an approved eligibility demonstration for each hazardous waste combustor.
(2) Test methods. (i) If you operate a cement kiln or a combustor
equipped with a dry acid gas scrubber, you must should use EPA Method
320/321 or ASTM D 6735-01, or an equivalent method, to measure hydrogen
chloride, and the back-half (caustic impingers) of Method 26/26A, or an
equivalent method, to measure chlorine gas.
(ii) If you operate an incinerator, boiler, or lightweight
aggregate kiln, you must use EPA Method 320/321 or ASTM D 6735-01, or
an equivalent method, to measure hydrogen chloride, and Method 26/26A,
or an equivalent method, to measure total chlorine, and calculate
chlorine gas by difference if:
(A) The bromine/chlorine ratio in feedstreams is greater than 5
percent; or
(B) The sulfur/chlorine ratio in feedstreams is greater than 50 percent.
(3) Operating parameter limits. (i) You must establish limits on
the same operating parameters that apply to sources complying with the
MACT standard for total chlorine under Sec. 63.1209(o), except that
feedrate limits on total chlorine and chloride must be established as
specified under paragraph (e)(3)(ii) of this section.
(ii) Annual rolling average feedrate. You must establish an annual
rolling average feedrate limit for total chlorine and chloride as the
average of the test run averages during the comprehensive performance test.
(A) To document compliance with the feedrate limit, you must know
the total chlorine and chloride concentration of feedstreams at all
times and continuously monitor the flowrate of all feedstreams.
(B) You must measure the flowrate of each feedstream at least once
each minute and update the annual rolling average hourly based on the
average of the 60 previous 1-minute measurements.
(f) Changes--(1) Changes over which you have control. (i) Changes
in design, operation, or maintenance of a hazardous waste combustor
that may affect the rate of emissions of HCl-equivalents from the
combustor are subject to the requirements of Sec. 63.1206(b)(5).
(ii) If you change the information documented in the demonstration
of eligibility for the HCl-equivalent emission rate limit and which is
used to establish the HCl-equivalent emission rate limit, you are
subject to the following requirements:
(A) Changes that would decrease the allowable HCl-equivalent
emission rate limit. If you plan to make a change that would decrease
the allowable HCl-equivalent emission rate limit documented in your
eligibility demonstration, you must comply with Sec.
63.1206(b)(5)(i)(A)-(C);
(B) Changes that would not decrease the allowable HCl-equivalent
emission rate limit. (1) If you determine that a change would not
decrease the allowable HCl-equivalent emission rate limit documented in
your eligibility demonstration, you must document the change in the
operating record upon making such change.
(2) If the change would increase your allowable HCl-equivalent
emission rate limit and you elect to establish a higher HCl-equivalent
limit, you must submit a revised eligibility demonstration for review
and approval. Upon approval of the revised eligibility demonstration,
you must comply with Sec. 63.1206(b)(5)(i)(A)(2), (B), and (C).
(2) Changes over which you do not have control. (i) You must review
the documentation you use in your eligibility demonstration every five
years on the anniversary of the comprehensive performance test and
submit for review and approval with the comprehensive performance test
plan either a certification that the information used in your
eligibility demonstration has not changed in a manner that would
decrease the allowable HCl-equivalent emission rate limit, or a revised
eligibility demonstration for a revised HCl-equivalent emission rate limit.
(ii) If you determine that you cannot demonstrate compliance with a
lower allowable HCl-equivalent emission rate limit during the
comprehensive performance test because you cannot complete changes to
the design or operation of the source prior to the test, you may
request that the permitting authority grant you additional time as
necessary to make those changes, not to exceed three years.

Table 1. to Sec. 63.1215.--Allowable Toxicity-Weighted Emission Rate Expressed in HCL Equivalents (lb/hr)
----------------------------------------------------------------------------------------------------------------
Distance to property boundary (m)
Stack ht (m) -----------------------------------------------------------------------------------
10 30 50 100 200 500
----------------------------------------------------------------------------------------------------------------
2........................... 0.0244 0.0322 0.0338 0.0627 0.173 0.766
5........................... 0.0475 0.0612 0.0881 0.168 0.309 0.881
10.......................... 0.165 0.187 0.216 0.336 0.637 1.59
20.......................... 0.661 1.01 1.01 1.2 1.87 4.31
35.......................... 2.02 2.02 4.04 4.11 5.08 10.4
50.......................... 4.11 4.11 4.11 9.74 10.8 18.0
----------------------------------------------------------------------------------------------------------------

[[Page 21375]]

13. Section 63.1216 and an undesignated center heading are added to
subpart EEE to read as follows:

Emissions Standards and Operating Limits for Solid Fuel-Fired Boilers,
Liquid Fuel-Fired Boilers, and Hydrochloric Acid Production Furnaces

Sec. 63.1216 What are the standards for solid fuel-fired boilers that
burn hazardous waste?

(a) Emission limits for existing sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1) For dioxin and furan, either carbon monoxide or hydrocarbon
emissions in excess of the limits provided by paragraph (a)(5) of this
section;
(2) Mercury in excess of 10 ug/dscm corrected to 7 percent oxygen;
(3) Except for an area source as defined in Sec. 63.2, cadmium and
lead in excess of 170 ug/dscm, combined emissions, corrected to 7
percent oxygen;
(4) Except for an area source as defined in Sec. 63.2, arsenic,
beryllium, and chromium in excess of 210 ug/dscm, combined emissions,
corrected to 7 percent oxygen;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(a)(5)(ii) of this section, you must also document that, during the
destruction and removal efficiency (DRE) test runs or their equivalent
as provided by Sec. 63.1206(b)(7), hydrocarbons do not exceed 10 parts
per million by volume during those runs, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis, corrected to 7 percent oxygen, and reported as propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Except for an area source as defined in Sec. 63.2, hydrogen
chloride and chlorine gas in excess of 440 parts per million by volume,
combined emissions, expressed as a chloride (Cl^(-))
equivalent, dry basis and corrected to 7 percent oxygen; and
(7) Except for an area source as defined in Sec. 63.2, particulate
matter in excess of 68 mg/dscm corrected to 7 percent oxygen.
(b) Emission limits for new sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1) For dioxin and furan, either carbon monoxide or hydrocarbon
emissions in excess of the limits provided by paragraph (b)(5) of this
section;
(2) Mercury in excess of 10 [mu]g/dscm corrected to 7 percent oxygen;
(3) Except for an area source as defined in Sec. 63.2, cadmium and
lead in excess of 170 [mu]g/dscm, combined emissions, corrected to 7
percent oxygen;
(4) Except for an area source as defined in Sec. 63.2, arsenic,
beryllium, and chromium in excess of 190 [mu]g/dscm, combined
emissions, corrected to 7 percent oxygen;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(b)(5)(ii) of this section, you must also document that, during the
destruction and removal efficiency (DRE) test runs or their equivalent
as provided by Sec. Sec. 63.1206(b)(7), hydrocarbons do not exceed 10
parts per million by volume during those runs, over an hourly rolling
average (monitored continuously with a continuous emissions monitoring
system), dry basis, corrected to 7 percent oxygen, and reported as
propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Except for an area source as defined in Sec. 63.2, hydrogen
chloride and chlorine gas in excess of 73 parts per million by volume,
combined emissions, expressed as a chloride (Cl^(-))
equivalent, dry basis and corrected to 7 percent oxygen; and
(7) Except for an area source as defined in Sec. 63.2, particulate
matter in excess of 34 mg/dscm corrected to 7 percent oxygen.
(c) Destruction and removal efficiency (DRE) standard--(1) 99.99%
DRE. Except as provided in paragraph (c)(2) of this section, you must
achieve a DRE of 99.99% for each principle organic hazardous
constituent (POHC) designated under paragraph (c)(3) of this section.
You must calculate DRE for each POHC from the following equation:

Sec. 63.1217 What are the standards for liquid fuel-fired boilers
that burn hazardous waste?

(a) Emission limits for existing sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:

[[Page 21376]]

(1)(i) Dioxin and furan in excess of 0.40 ng TEQ/dscm corrected to
7 percent oxygen for incinerators equipped with either a waste heat
boiler or dry air pollution control system; or
(ii) Either carbon monoxide or hydrocarbon emissions in excess of
the limits provided by paragraph (a)(5) of this section for sources not
equipped with either a waste heat boiler or dry air pollution control system;
(iii) A source equipped a wet air pollution control system followed
by a dry air pollution control system is not considered to be a dry air
pollution control system, and a source equipped with a dry air
pollution control system followed a wet air pollution control system is
considered to be a dry air pollution control system for purposes of
this emission limit;
(2) Mercury in excess of 3.7 x 10^-6 lbs mercury
emissions attributable to the hazardous waste per million British
thermal unit heat input from the hazardous waste;
(3) Except for an area source as defined in Sec. 63.2, in excess
of 1.1 x 10^-5 lbs combined emissions of cadmium and lead
attributable to the hazardous waste per million British thermal unit
heat input from the hazardous waste;
(4) Except for an area source as defined in Sec. 63.2, in excess
of 1.1 x 10^-4 lbs chromium emissions attributable to the
hazardous waste per million British thermal unit heat input from the
hazardous waste;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(a)(5)(ii) of this section, you must also document that, during the
destruction and removal efficiency (DRE) test runs or their equivalent
as provided by Sec. 63.1206(b)(7), hydrocarbons do not exceed 10 parts
per million by volume during those runs, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis, corrected to 7 percent oxygen, and reported as propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Except for an area source as defined in Sec. 63.2, in excess
of 2.5 x0^-2 lbs combined emissions of hydrogen chloride and
chlorine gas attributable to the hazardous waste per million British
thermal unit heat input from the hazardous waste; and
(7) Except for an area source as defined in Sec. 63.2 or as
provided by paragraph (e)(2) of this section, particulate matter in
excess of 59 mg/dscm corrected to 7 percent oxygen.
(b) Emission limits for new sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1)(i) Dioxin and furan in excess of 0.015 ng TEQ/dscm corrected to
7 percent oxygen for incinerators equipped with either a waste heat
boiler or dry air pollution control system; or
(ii) Either carbon monoxide or hydrocarbon emissions in excess of
the limits provided by paragraph (a)(5) of this section for sources not
equipped with either a waste heat boiler or dry air pollution control system;
(iii) A source equipped a wet air pollution control system followed
by a dry air pollution control system is not considered to be a dry air
pollution control system, and a source equipped with a dry air
pollution control system followed a wet air pollution control system is
considered to be a dry air pollution control system for purposes of
this emission limit;
(2) In excess of 3.8 x 10^-7 lbs mercury emissions
attributable to the hazardous waste per million British thermal unit
heat input from the hazardous waste;
(3) Except for an area source as defined in Sec. 63.2, in excess
of 4.3 x 10^-6 lbs combined emissions of cadmium and lead
attributable to the hazardous waste per million British thermal unit
heat input from the hazardous waste;
(4) Except for an area source as defined in Sec. 63.2, in excess
of 3.6 x 10^-5 lbs chromium emissions attributable to the
hazardous waste per million British thermal unit heat input from the
hazardous waste;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(a)(5)(ii) of this section, you must also document that, during the
destruction and removal efficiency (DRE) test runs or their equivalent
as provided by Sec. 63.1206(b)(7), hydrocarbons do not exceed 10 parts
per million by volume during those runs, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis, corrected to 7 percent oxygen, and reported as propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Except for an area source as defined in Sec. 63.2, in excess
of 7.2 x 10^-4 lbs combined emissions of hydrogen chloride
and chlorine gas attributable to the hazardous waste per million
British thermal unit heat input from the hazardous waste; and
(7) Except for an area source as defined in Sec. 63.2 or as
provided in paragraph (e)(3) of this section, particulate matter in
excess of 9.8 mg/dscm corrected to 7 percent oxygen.
(c) Destruction and removal efficiency (DRE) standard--(1) 99.99%
DRE. Except as provided in paragraph (c)(2) of this section, you must
achieve a DRE of 99.99% for each principle organic hazardous
constituent (POHC) designated under paragraph (c)(3) of this section.
You must calculate DRE for each POHC from the following equation:

DRE = [1-(Wout / Win)] x 100%
Where:
Win = mass feedrate of one POHC in a waste feedstream; and
Wout = mass emission rate of the same POHC present in exhaust emissions
prior to release to the atmosphere.
(2) 99.9999% DRE. If you burn the dioxin-listed hazardous wastes
F020, F021, F022, F023, F026, or F027 (see Sec. 261.31 of this
chapter), you must achieve a DRE of 99.9999% for each POHC that you
designate under paragraph (c)(3) of this section. You must demonstrate
this DRE performance on POHCs that are more difficult to incinerate
than tetra-, penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans.
You must use the equation in paragraph (c)(1) of this section to
calculate DRE for each POHC. In addition, you must notify the
Administrator of your intent to incinerate hazardous wastes F020, F021,
F022, F023, F026, or F027.
(3) Principal organic hazardous constituents (POHCs). (i) You must
treat the POHCs in the waste feed that you specify under paragraph
(c)(3)(ii) of this section to the extent required by paragraphs (c)(1)
and (c)(2) of this section.
(ii) You must specify one or more POHCs from the list of hazardous air

[[Page 21377]]

pollutants established by 42 U.S.C. 7412(b)(1), excluding caprolactam
(CAS number 105602) as provided by Sec. 63.60, for each waste to be
burned. You must base this specification on the degree of difficulty of
incineration of the organic constituents in the waste and on their
concentration or mass in the waste feed, considering the results of
waste analyses or other data and information.
(d) Significant figures. The emission limits provided by paragraphs
(a) and (b) of this section are presented with two significant figures.
Although you must perform intermediate calculations using at least
three significant figures, you may round the resultant emission levels
to two significant figures to document compliance.
(e) Alternative to the particulate matter standard for liquid fuel-
fired boilers. (1) General. In lieu of complying with the applicable
particulate matter standards of paragraphs (a)(7) and (b)(7) of this
section, you may elect to comply with the following alternative metal
emission control requirements:
(2) Alternative metal emission control requirements for existing
sources. (i) You must not discharge or cause combustion gases to be
emitted into the atmosphere that contain in excess of 1.1 x
10^-5 lbs combined emissions of cadmium, lead, and selenium
attributable to the hazardous waste per million British thermal unit
heat input from the hazardous waste, corrected to 7 percent oxygen; and,
(ii) You must not discharge or cause combustion gases to be emitted
into the atmosphere that contain in excess of 7.7 x 10^-5 lbs
combined emissions of antimony, arsenic, beryllium, chromium, cobalt,
manganese, and nickel attributable to the hazardous waste per million
British thermal unit heat input from the hazardous waste, corrected to
7 percent oxygen.
(3) Alternative metal emission control requirements for new
sources. (i) You must not discharge or cause combustion gases to be
emitted into the atmosphere that contain in excess of 4.3 x
10^-6 lbs combined emissions of cadmium, lead, and selenium
attributable to the hazardous waste per million British thermal unit
heat input from the hazardous waste, corrected to 7 percent oxygen;
and,
(ii) You must not discharge or cause combustion gases to be emitted
into the atmosphere that contain in excess of 3.6 x 10^-5 lbs
combined emissions of antimony, arsenic, beryllium, chromium, cobalt,
manganese, and nickel attributable to the hazardous waste per million
British thermal unit heat input from the hazardous waste, corrected to
7 percent oxygen.
15. Section 63.1218 is added to subpart EEE to read as follows:

Sec. 63.1218 What are the standards for hydrochloric acid production
furnaces that burn hazardous waste?

(a) Emission limits for existing sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1) Dioxin and furan emissions in excess of 0.40 ng TEQ/dscm,
corrected to 7 percent oxygen;
(2) For mercury, hydrogen chloride and chlorine gas emissions in
excess of the levels provided by paragraph (a)(6) of this section;
(3) For lead and cadmium, hydrogen chloride and chlorine gas
emissions in excess of the levels provided by paragraph (a)(6) of this
section;
(4) For arsenic, beryllium, and chromium, hydrogen chloride and
chlorine gas emissions in excess of the levels provided by paragraph
(a)(6) of this section;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(a)(5)(ii) of this section, you must also document that, during the
destruction and removal efficiency (DRE) test runs or their equivalent
as provided by Sec. 63.1206(b)(7), hydrocarbons do not exceed 10 parts
per million by volume during those runs, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis, corrected to 7 percent oxygen, and reported as propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) For hydrogen chloride and chlorine gas, either:
(i) Emission in excess of 14 parts per million by volume, combined
emissions, expressed as a chloride (Cl^(-) equivalent, dry
basis and corrected to 7 percent oxygen; or
(ii) Emissions greater than the levels that would be emitted if the
source is achieving a system removal efficiency (SRE) of less than
99.9927 percent for total chlorine and chloride fed to the combustor.
You must calculate SRE from the following equation:

SRE = [1-(Cl out / Cl in)] X 100%

Where:

Clin = mass feedrate of total chlorine or chloride in all
feedstreams, reported as chloride; and
Clout = mass emission rate of hydrogen chloride and chlorine
gas, reported as chloride, in exhaust emissions prior to release to the
atmosphere.

(7) For particulate matter, hydrogen chloride and chlorine gas
emissions in excess of the levels provided by paragraph (a)(6) of this
section.
(b) Emission limits for new sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1) Dioxin and furan emissions in excess of 0.40 ng TEQ/dscm,
corrected to 7 percent oxygen;
(2) For mercury, hydrogen chloride and chlorine gas emissions in
excess of the levels provided by paragraph (a)(6) of this section;
(3) For lead and cadmium, hydrogen chloride and chlorine gas
emissions in excess of the levels provided by paragraph (a)(6) of this
section;
(4) For arsenic, beryllium, and chromium, hydrogen chloride and
chlorine gas emissions in excess of the levels provided by paragraph
(a)(6) of this section;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(b)(5)(ii) of this section, you must also document that, during the
destruction and removal efficiency (DRE) test runs or their equivalent
as provided by Sec. 63.1206(b)(7), hydrocarbons do not exceed 10 parts
per million by volume during those runs, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis, corrected to 7 percent oxygen, and reported as propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) For hydrochloric acid and chlorine gas, either:
(i) Emission in excess of 1.2 parts per million by volume, combined
emissions, expressed as a chloride

[[Page 21378]]

(Cl ^(-)) equivalent, dry basis and corrected to 7 percent
oxygen; or
(ii) Emissions greater than the levels that would be emitted if the
source is achieving a system removal efficiency (SRE) of less than
99.99937 percent for total chlorine and chloride fed to the combustor.
You must calculate SRE from the following equation:

SRE = [1-(Cl out / Cl in)] x 100%
Where:

Cl in = mass feedrate of total chlorine or chloride in all
feedstreams, reported as chloride; and
Cl out = mass emission rate of hydrogen chloride and
chlorine gas, reported as chloride, in exhaust emissions prior to
release to the atmosphere.

(7) For particulate matter, hydrogen chloride and chlorine gas
emissions in excess of the levels provided by paragraph (a)(6) of this
section.
(c) Destruction and removal efficiency (DRE) standard--(1) 99.99%
DRE. Except as provided in paragraph (c)(2) of this section, you must
achieve a DRE of 99.99% for each principle organic hazardous
constituent (POHC) designated under paragraph (c)(3) of this section.
You must calculate DRE for each POHC from the following equation:

DRE = [1-(Wout / Win)] x 100%

Where:

Win = mass feedrate of one POHC in a waste feedstream;
and
Wout = mass emission rate of the same POHC present in
exhaust emissions prior to release to the atmosphere.

Replacement Emissions Standards and Operating Limits for Incinerators,
Cement Kilns, and Lightweight Aggregate Kilns

Sec. 63.1219 What are the replacement standards for hazardous waste
incinerators?

(a) Emission limits for existing sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1)(i) Dioxin and furan in excess of 0.28 ng TEQ/dscm corrected to
7 percent oxygen for incinerators equipped with either a waste heat
boiler or dry air pollution control system; or
(ii) Dioxin and furan in excess of 0.40 ng TEQ/dscm corrected to 7
percent oxygen for sources not equipped with either a waste heat boiler
or dry air pollution control system;
(iii) A source equipped a wet air pollution control system followed
by a dry air pollution control system is not considered to be a dry air
pollution control system, and a source equipped with a dry air
pollution control system followed a wet air pollution control system is
considered to be a dry air pollution control system for purposes of
this emission limit;
(2) Mercury in excess of 130 [mu]g/dscm corrected to 7 percent oxygen;
(3) Cadmium and lead in excess of 59 [mu]g/dscm, combined
emissions, corrected to 7 percent oxygen;
(4) Arsenic, beryllium, and chromium in excess of 84 [mu]g/dscm,
combined emissions, corrected to 7 percent oxygen;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(a)(5)(ii) of this section, you must also document that, during the
destruction and removal efficiency (DRE) test runs or their equivalent
as provided by Sec. 63.1206(b)(7), hydrocarbons do not exceed 10 parts
per million by volume during those runs, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis, corrected to 7 percent oxygen, and reported as propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Hydrogen chloride and chlorine gas (total chlorine) in excess
of 1.5 parts per million by volume, combined emissions, expressed as a
chloride (Cl^(-)) equivalent, dry basis and corrected to 7
percent oxygen; and
(7) Except as provided by paragraph (e)(2) of this section,
particulate matter in excess of 34 mg/dscm corrected to 7 percent oxygen.
(b) Emission limits for new sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1)(i) Dioxin and furans in excess of 0.11 ng TEQ/dscm corrected to
7 percent oxygen for incinerators equipped with either a waste heat
boiler or dry air pollution control system; or
(ii) Dioxin and furans in excess of 0.20 ng TEQ/dscm corrected to 7
percent oxygen for sources not equipped with either a waste heat boiler
or dry air pollution control system;
(iii) A source equipped a wet air pollution control system followed
by a dry air pollution control system is not considered to be a dry air
pollution control system, and a source equipped with a dry air
pollution control system followed a wet air pollution control system is
considered to be a dry air pollution control system for purposes of
this standard;
(2) Mercury in excess of 8 [mu]g/dscm corrected to 7 percent oxygen;
(3) Cadmium and lead in excess of 6.5 [mu]g/dscm, combined
emissions, corrected to 7 percent oxygen;
(4) Arsenic, beryllium, and chromium in excess of 8.9 [mu]g/dscm,
combined emissions, corrected to 7 percent oxygen;
(5) For carbon monoxide and hydrocarbons, either:
(i) Carbon monoxide in excess of 100 parts per million by volume,
over an

[[Page 21379]]

hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis and corrected to 7 percent
oxygen. If you elect to comply with this carbon monoxide standard
rather than the hydrocarbon standard under paragraph (b)(5)(ii) of this
section, you must also document that, during the destruction and
removal efficiency (DRE) test runs or their equivalent as provided by
Sec. 63.1206(b)(7), hydrocarbons do not exceed 10 parts per million by
volume during those runs, over an hourly rolling average (monitored
continuously with a continuous emissions monitoring system), dry basis,
corrected to 7 percent oxygen, and reported as propane; or
(ii) Hydrocarbons in excess of 10 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Hydrogen chloride and chlorine gas in excess of 0.18 parts per
million by volume, combined emissions, expressed as a chloride
(Cl^(-)) equivalent, dry basis and corrected to 7 percent
oxygen; and
(7) Except as provided by paragraph (e)(3) of this section,
particulate matter in excess of 1.6 mg/dscm corrected to 7 percent
oxygen.
(c) Destruction and removal efficiency (DRE) standard--(1) 99.99%
DRE. Except as provided in paragraph (c)(2) of this section, you must
achieve a destruction and removal efficiency (DRE) of 99.99% for each
principle organic hazardous constituent (POHC) designated under
paragraph (c)(3) of this section. You must calculate DRE for each POHC
from the following equation:

DRE = [1 - (Wout / Win )] x 100%

Where:
Win = mass feedrate of one POHC in a waste feedstream; and
Wout = mass emission rate of the same POHC present in
exhaust emissions prior to release to the atmosphere.

(2) 99.9999% DRE. If you burn the dioxin-listed hazardous wastes
F020, F021, F022, F023, F026, or F027 (see Sec. 261.31 of this
chapter), you must achieve a DRE of 99.9999% for each POHC that you
designate under paragraph (c)(3) of this section. You must demonstrate
this DRE performance on POHCs that are more difficult to incinerate
than tetra-, penta-, and hexachlorodibenzo-p-dioxins and dibenzofurans.
You must use the equation in paragraph (c)(1) of this section to
calculate DRE for each POHC. In addition, you must notify the
Administrator of your intent to incinerate hazardous wastes F020, F021,
F022, F023, F026, or F027.
(3) Principal organic hazardous constituent (POHC). (i) You must
treat each POHC in the waste feed that you specify under paragraph
(c)(3)(ii) of this section to the extent required by paragraphs (c)(1)
and (c)(2) of this section.
(ii) You must specify one or more POHCs from the list of hazardous
air pollutants established by 42 U.S.C. 7412(b)(1), excluding
caprolactam (CAS number 105602) as provided by Sec. 63.60, for each
waste to be burned. You must base this specification on the degree of
difficulty of incineration of the organic constituents in the waste and
on their concentration or mass in the waste feed, considering the
results of waste analyses or other data and information.
(d) Significant figures. The emission limits provided by paragraphs
(a) and (b) of this section are presented with two significant figures.
Although you must perform intermediate calculations using at least
three significant figures, you may round the resultant emission levels
to two significant figures to document compliance.
(e) Alternative to the particulate matter standard for
incinerators--(1) General. In lieu of complying with the applicable
particulate matter standards of paragraphs (a)(7) and (b)(7) of this
section, you may elect to comply with the following alternative metal
emission control requirements:
(2) Alternative metal emission control requirements for existing
sources. (i) You must not discharge or cause combustion gases to be
emitted into the atmosphere that contain cadmium, lead, and selenium in
excess of 59 [mu]g/dscm, combined emissions, corrected to 7 percent
oxygen; and,
(ii) You must not discharge or cause combustion gases to be emitted
into the atmosphere that contain antimony, arsenic, beryllium,
chromium, cobalt, manganese, and nickel in excess of 84 [mu]g/dscm,
combined emissions, corrected to 7 percent oxygen.
(3) Alternative metal emission control requirements for new
sources. (i) You must not discharge or cause combustion gases to be
emitted into the atmosphere that contain cadmium, lead, and selenium in
excess of 6.5/dscm, combined emissions, corrected to 7 percent oxygen; and,
(ii) You must not discharge or cause combustion gases to be emitted
into the atmosphere that contain antimony, arsenic, beryllium,
chromium, cobalt, manganese, and nickel in excess of 8.9 [mu]g/dscm,
combined emissions, corrected to 7 percent oxygen.
17. Section 63.1220 is added to subpart EEE to read as follows:

Sec. 63.1220 What are the replacement standards for hazardous waste
burning cement kilns?

(a) Emission limits for existing sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1)(i) Dioxin and furan in excess of 0.20 ng TEQ/dscm corrected to
7 percent oxygen; or
(ii) Dioxin and furan in excess of 0.40 ng TEQ/dscm corrected to 7
percent oxygen provided that the combustion gas temperature at the
inlet to the initial dry particulate matter control device is 400[deg]F
or lower based on the average of the test run average temperatures;
(2) Mercury in excess of 64 [mu]g/dscm corrected to 7 percent oxygen;
(3) In excess of 4.0 x 10^-4 lbs combined emissions of
cadmium and lead attributable to the hazardous waste per million
British thermal unit heat input from the hazardous waste;
(4) In excess of 1.4 x 10^-5 lbs combined emissions of
arsenic, beryllium, and chromium attributable to the hazardous waste
per million British thermal unit heat input from the hazardous waste;
(5) Carbon monoxide and hydrocarbons. (i) For kilns equipped with a
by-pass duct or midkiln gas sampling system, either:
(A) Carbon monoxide in the by-pass duct or mid-kiln gas sampling
system in excess of 100 parts per million by volume, over an hourly
rolling average (monitored continuously with a continuous emissions
monitoring system), dry basis and corrected to 7 percent oxygen. If you
elect to comply with this carbon monoxide standard rather than the
hydrocarbon standard under paragraph (a)(5)(i)(B) of this section, you
must also document that, during the destruction and removal efficiency
(DRE) test runs or their equivalent as provided by Sec. 63.1206(b)(7),
hydrocarbons in the by-pass duct or mid-kiln gas sampling system do not
exceed 10 parts per million by volume during those runs, over an hourly
rolling average (monitored continuously with a continuous emissions
monitoring system), dry basis, corrected to 7 percent oxygen, and
reported as propane; or
(B) Hydrocarbons in the by-pass duct or midkiln gas sampling system
in excess of 10 parts per million by volume, over an hourly rolling
average (monitored continuously with a continuous emissions monitoring
system), dry basis, corrected to 7

[[Page 21380]]

percent oxygen, and reported as propane;
(ii) For kilns not equipped with a by-pass duct or midkiln gas
sampling system, either:
(A) Hydrocarbons in the main stack in excess of 20 parts per
million by volume, over an hourly rolling average (monitored
continuously with a continuous emissions monitoring system), dry basis,
corrected to 7 percent oxygen, and reported as propane; or
(B) Carbon monoxide in the main stack in excess of 100 parts per
million by volume, over an hourly rolling average (monitored
continuously with a continuous emissions monitoring system), dry basis
and corrected to 7 percent oxygen. If you elect to comply with this
carbon monoxide standard rather than the hydrocarbon standard under
paragraph (a)(5)(ii)(A) of this section, you also must document that,
during the destruction and removal efficiency (DRE) test runs or their
equivalent as provided by Sec. 63.1206(b)(7), hydrocarbons in the main
stack do not exceed 20 parts per million by volume during those runs,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis, corrected to 7
percent oxygen, and reported as propane.
(6) Hydrogen chloride and chlorine gas in excess of 110 parts per
million by volume, combined emissions, expressed as a chloride
(Cl^(-)) equivalent, dry basis, corrected to 7 percent
oxygen; and
(7) Particulate matter in excess of 65 mg/dscm corrected to 7
percent oxygen.
(b) Emission limits for new sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1)(i) Dioxin and furan in excess of 0.20 ng TEQ/dscm corrected to
7 percent oxygen; or
(ii) Dioxin and furan in excess of 0.40 ng TEQ/dscm corrected to 7
percent oxygen provided that the combustion gas temperature at the
inlet to the initial dry particulate matter control device is 400[deg]F
or lower based on the average of the test run average temperatures;
(2) Mercury in excess of 35 [mu]g/dscm corrected to 7 percent oxygen;
(3) In excess of 6.2 x 10^-5 lbs combined emissions of
cadmium and lead attributable to the hazardous waste per million
British thermal unit heat input from the hazardous waste;
(4) In excess of 1.4 x 10^-5 lbs combined emissions of
arsenic, beryllium, and chromium attributable to the hazardous waste
per million British thermal unit heat input from the hazardous waste;
(5) Carbon monoxide and hydrocarbons. (i) For kilns equipped with a
by-pass duct or midkiln gas sampling system, carbon monoxide and
hydrocarbons emissions are limited in both the bypass duct or midkiln
gas sampling system and the main stack as follows:
(A) Emissions in the by-pass or midkiln gas sampling system are
limited to either:
(1) Carbon monoxide in excess of 100 parts per million by volume,
over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis and corrected to 7
percent oxygen. If you elect to comply with this carbon monoxide
standard rather than the hydrocarbon standard under paragraph
(b)(5)(i)(A)(2) of this section, you also must document that, during
the destruction and removal efficiency (DRE) test runs or their
equivalent as provided by Sec. 63.1206(b)(7), hydrocarbons do not
exceed 10 parts per million by volume during those runs, over an hourly
rolling average (monitored continuously with a continuous emissions
monitoring system), dry basis, corrected to 7 percent oxygen, and
reported as propane; or
(2) Hydrocarbons in the by-pass duct or midkiln gas sampling system
in excess of 10 parts per million by volume, over an hourly rolling
average (monitored continuously with a continuous emissions monitoring
system), dry basis, corrected to 7 percent oxygen, and reported as
propane; and
(B) Hydrocarbons in the main stack are limited, if construction of
the kiln commenced after April 19, 1996 at a plant site where a cement
kiln (whether burning hazardous waste or not) did not previously exist,
to 50 parts per million by volume, over a 30-day block average
(monitored continuously with a continuous monitoring system), dry
basis, corrected to 7 percent oxygen, and reported as propane.
(ii) For kilns not equipped with a by-pass duct or midkiln gas
sampling system, hydrocarbons and carbon monoxide are limited in the
main stack to either:
(A) Hydrocarbons not exceeding 20 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane; or
(B)(1) Carbon monoxide not exceeding 100 parts per million by
volume, over an hourly rolling average (monitored continuously with a
continuous emissions monitoring system), dry basis, corrected to 7
percent oxygen; and
(2) Hydrocarbons not exceeding 20 parts per million by volume, over
an hourly rolling average (monitored continuously with a continuous
monitoring system), dry basis, corrected to 7 percent oxygen, and
reported as propane at any time during the destruction and removal
efficiency (DRE) test runs or their equivalent as provided by Sec.
63.1206(b)(7); and
(3) If construction of the kiln commenced after April 19, 1996 at a
plant site where a cement kiln (whether burning hazardous waste or not)
did not previously exist, hydrocarbons are limited to 50 parts per
million by volume, over a 30-day block average (monitored continuously
with a continuous monitoring system), dry basis, corrected to 7 percent
oxygen, and reported as propane.
(6) Hydrogen chloride and chlorine gas in excess of 78 parts per
million, combined emissions, expressed as a chloride (Cl^(-))
equivalent, dry basis and corrected to 7 percent oxygen; and
(7) Particulate matter in excess of 13 mg/dscm corrected to 7
percent oxygen.
(c) Destruction and removal efficiency (DRE) standard--(1) 99.99%
DRE. Except as provided in paragraph (c)(2) of this section, you must
achieve a destruction and removal efficiency (DRE) of 99.99% for each
principle organic hazardous constituent (POHC) designated under
paragraph (c)(3) of this section. You must calculate DRE for each POHC
from the following equation:

DRE = [1 - (Wout / Win )] x 100%

Where:

Win = mass feedrate of one POHC in a waste feedstream; and
Wout = mass emission rate of the same POHC present in
exhaust emissions prior to release to the atmosphere.

[[Page 21381]]

(3) Principal organic hazardous constituent (POHC). (i) You must
treat each POHC in the waste feed that you specify under paragraph
(c)(3)(ii) of this section to the extent required by paragraphs (c)(1)
and (c)(2) of this section.
(ii) You must specify one or more POHCs from the list of hazardous
air pollutants established by 42 U.S.C. 7412(b)(1), excluding
caprolactam (CAS number 105602) as provided by Sec. 63.60, for each
waste to be burned. You must base this specification on the degree of
difficulty of incineration of the organic constituents in the waste and
on their concentration or mass in the waste feed, considering the
results of waste analyses or other data and information.
(d) Cement kilns with in-line kiln raw mills. The provisions of
Sec. 63.1204(d) apply.
(1) General. (i) You must conduct performance testing when the raw
mill is on-line and when the mill is off-line to demonstrate compliance
with the emission standards, and you must establish separate operating
parameter limits under Sec. 63.1209 for each mode of operation, except
as provided by paragraph (d)(1)(iv) of this section.
(ii) You must document in the operating record each time you change
from one mode of operation to the alternate mode and begin complying
with the operating parameter limits for that alternate mode of
operation.
(iii) You must establish rolling averages for the operating
parameter limits anew (i.e., without considering previous recordings)
when you begin complying with the operating limits for the alternate
mode of operation.
(iv) If your in-line kiln raw mill has dual stacks, you may assume
that the dioxin/furan emission levels in the by-pass stack and the
operating parameter limits determined during performance testing of the
by-pass stack when the raw mill is off-line are the same as when the
mill is on-line.
(2) Emissions averaging. You may comply with the mercury,
semivolatile metal, low volatile metal, and hydrochloric acid/chlorine
gas emission standards on a time-weighted average basis under the
following procedures:
(i) Averaging methodology. You must calculate the time-weighted
average emission concentration with the following equation:

Ctotal = {Cmill-off x (Tmill-off/
(Tmill-off + Tmill-on)){time} +
{Cmill-on x (Tmill-on/(Tmill-off +
Tmill-on )){time}

Where:

Ctotal = time-weighted average concentration of a regulated
constituent considering both raw mill on time and off time;
Cmill-off = average performance test concentration of
regulated constituent with the raw mill off-line;
Cmill-on = average performance test concentration of
regulated constituent with the raw mill on-line;
Tmill-off = time when kiln gases are not routed through the
raw mill; and
Tmill-on = time when kiln gases are routed through the raw mill.

(ii) Compliance. (A) If you use this emission averaging provision,
you must document in the operating record compliance with the emission
standards on an annual basis by using the equation provided by
paragraph (d)(2) of this section.
(B) Compliance is based on one-year block averages beginning on the
day you submit the initial notification of compliance.
(iii) Notification. (A) If you elect to document compliance with
one or more emission standards using this emission averaging provision,
you must notify the Administrator in the initial comprehensive
performance test plan submitted under Sec. 63.1207(e).
(B) You must include historical raw mill operation data in the
performance test plan to estimate future raw mill down-time and
document in the performance test plan that estimated emissions and
estimated raw mill down-time will not result in an exceedance of an
emission standard on an annual basis.
(C) You must document in the notification of compliance submitted
under Sec. 63.1207(j) that an emission standard will not be exceeded
based on the documented emissions from the performance test and
predicted raw mill down-time.
(e) Preheater or preheater/precalciner kilns with dual stacks--(1)
General. You must conduct performance testing on each stack to
demonstrate compliance with the emission standards, and you must
establish operating parameter limits under Sec. 63.1209 for each
stack, except as provided by paragraph (d)(1)(iv) of this section for
dioxin/furan emissions testing and operating parameter limits for the
by-pass stack of in-line raw mills.
(2) Emissions averaging. You may comply with the mercury,
semivolatile metal, low volatile metal, and hydrochloric acid/chlorine
gas emission standards specified in this section on a gas flowrate-
weighted average basis under the following procedures:
(i) Averaging methodology. You must calculate the gas flowrate-
weighted average emission concentration using the following equation:

Ctot = {Cmain x (Qmain/
(Qmain + Qbypass)){time} + {Cbypass x
(Qbypass/(Qmain + Qbypass)){time}

Where:

Ctot = gas flowrate-weighted average concentration of the
regulated constituent;
Cmain = average performance test concentration demonstrated
in the main stack;
Cbypass = average performance test concentration
demonstrated in the bypass stack;
Qmain = volumetric flowrate of main stack effluent gas; and
Qbypass = volumetric flowrate of bypass effluent gas.

(ii) Compliance. (A) You must demonstrate compliance with the
emission standard(s) using the emission concentrations determined from
the performance tests and the equation provided by paragraph (e)(1) of
this section; and
(B) You must develop operating parameter limits for bypass stack
and main stack flowrates that ensure the emission concentrations
calculated with the equation in paragraph (e)(1) of this section do not
exceed the emission standards on a 12-hour rolling average basis. You
must include these flowrate limits in the Notification of Compliance.
(iii) Notification. If you elect to document compliance under this
emissions averaging provision, you must:
(A) Notify the Administrator in the initial comprehensive
performance test plan submitted under Sec. 63.1207(e). The performance
test plan must include, at a minimum, information describing the
flowrate limits established under paragraph (e)(2)(ii)(B) of this
section; and
(B) Document in the Notification of Compliance submitted under
Sec. 63.1207(j) the demonstrated gas flowrate-weighted average
emissions that you calculate with the equation provided by paragraph
(e)(2) of this section.
(f) Significant figures. The emission limits provided by paragraphs
(a) and (b) of this section are presented with two significant figures.
Although you must perform intermediate calculations using at least
three significant figures, you may round the resultant emission levels
to two significant figures to document compliance.
(g) [Reserved].
(h) When you comply with the particulate matter requirements of
paragraphs (a)(7) or (b)(7) of this section, you are exempt from the
New Source Performance Standard for particulate matter and opacity
under Sec. 60.60 of this chapter.

[[Page 21382]]

18. Section 63.1221 is added to subpart EEE to read as follows:

Sec. 63.1221 What are the replacement standards for hazardous waste
burning lightweight aggregate kilns?

(a) Emission limits for existing sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1) Dioxins and furans in excess of 0.40 ng TEQ/dscm corrected to 7
percent oxygen;
(2) Mercury in excess of 67 [mu]g/dscm corrected to 7 percent oxygen;
(3)(i) In excess of 3.1 x 10^-\4\ lbs combined emissions
of cadmium and lead attributable to the hazardous waste per million
British thermal unit heat input from the hazardous waste; and
(ii) Lead and cadmium in excess of 250 [mu]g/dscm, combined
emissions, corrected to 7 percent oxygen;
(4)(ii) In excess of 9.5 x 10^-\5\ lbs combined emissions
of arsenic, beryllium, and chromium attributable to the hazardous waste
per million British thermal unit heat input from the hazardous waste; and
(ii) Arsenic, beryllium, and chromium in excess of 110 [mu]g/dscm,
combined emissions, corrected to 7 percent oxygen;
(5) Carbon monoxide and hydrocarbons. (i) Carbon monoxide in excess
of 100 parts per million by volume, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis and corrected to 7 percent oxygen. If you elect to comply
with this carbon monoxide standard rather than the hydrocarbon standard
under paragraph (a)(5)(ii) of this section, you also must document
that, during the destruction and removal efficiency (DRE) test runs or
their equivalent as provided by Sec. 63.1206(b)(7), hydrocarbons do
not exceed 20 parts per million by volume during those runs, over an
hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane; or
(ii) Hydrocarbons in excess of 20 parts per million by volume, over
an hourly rolling average, dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Hydrogen chloride and chlorine gas in excess of 600 parts per
million by volume, combined emissions, expressed as a chloride
(Cl^(-)) equivalent, dry basis and corrected to 7 percent
oxygen; and
(7) Particulate matter in excess of 57 mg/dscm corrected to 7
percent oxygen.
(b) Emission limits for new sources. You must not discharge or
cause combustion gases to be emitted into the atmosphere that contain:
(1) Dioxins and furans in excess of 0.40 ng TEQ/dscm corrected to 7
percent oxygen;
(2) Mercury in excess of 67 [mu]g/dscm corrected to 7 percent oxygen;
(3)(i) In excess of 2.4 x 10^-\5\ lbs combined emissions
of cadmium and lead attributable to the hazardous waste per million
British thermal unit heat input from the hazardous waste; and
(ii) Lead and cadmium in excess of 43 [mu]g/dscm, combined
emissions, corrected to 7 percent oxygen;
(4)(i) In excess of 3.2 x 10^-\5\ lbs combined emissions
of arsenic, beryllium, and chromium attributable to the hazardous waste
per million British thermal unit heat input from the hazardous waste; and
(ii) Arsenic, beryllium, and chromium in excess of 110 [mu]g/dscm,
combined emissions, corrected to 7 percent oxygen;
(5) Carbon monoxide and hydrocarbons. (i) Carbon monoxide in excess
of 100 parts per million by volume, over an hourly rolling average
(monitored continuously with a continuous emissions monitoring system),
dry basis and corrected to 7 percent oxygen. If you elect to comply
with this carbon monoxide standard rather than the hydrocarbon standard
under paragraph (b)(5)(ii) of this section, you also must document
that, during the destruction and removal efficiency (DRE) test runs or
their equivalent as provided by Sec. 63.1206(b)(7), hydrocarbons do
not exceed 20 parts per million by volume during those runs, over an
hourly rolling average (monitored continuously with a continuous
emissions monitoring system), dry basis, corrected to 7 percent oxygen,
and reported as propane; or
(ii) Hydrocarbons in excess of 20 parts per million by volume, over
an hourly rolling average, dry basis, corrected to 7 percent oxygen,
and reported as propane;
(6) Hydrogen chloride and chlorine gas in excess of 600 parts per
million by volume, combined emissions, expressed as a chloride
(Cl^-) equivalent, dry basis and corrected to 7 percent
oxygen; and
(7) Particulate matter in excess of 23 mg/dscm corrected to 7
percent oxygen.
(c) Destruction and removal efficiency (DRE) standard--(1) 99.99%
DRE. Except as provided in paragraph (c)(2) of this section, you must
achieve a destruction and removal efficiency (DRE) of 99.99% for each
principal organic hazardous constituent (POHC) designated under
paragraph (c)(3) of this section. You must calculate DRE for each POHC
from the following equation:

DRE = [1^- (Wout / Win)] x 100%

Where:

Win = mass feedrate of one POHC in a waste feedstream; and
Wout = mass emission rate of the same POHC present in
exhaust emissions prior to release to the atmosphere.

(2) 99.9999% DRE. If you burn the dioxin-listed hazardous wastes
F020, F021, F022, F023, F026, or F027 (see Sec. 261.31 of this
chapter), you must achieve a destruction and removal efficiency (DRE)
of 99.9999% for each POHC that you designate under paragraph (c)(3) of
this section. You must demonstrate this DRE performance on POHCs that
are more difficult to incinerate than tetra-, penta-, and
hexachlorodibenzo-dioxins and dibenzofurans. You must use the equation
in paragraph (c)(1) of this section to calculate DRE for each POHC. In
addition, you must notify the Administrator of your intent to burn
hazardous wastes F020, F021, F022, F023, F026, or F027.
(3) Principal organic hazardous constituents (POHCs). (i) You must
treat each POHC in the waste feed that you specify under paragraph
(c)(3)(ii) of this section to the extent required by paragraphs (c)(1)
and (c)(2) of this section.
(ii) You must specify one or more POHCs from the list of hazardous
air pollutants established by 42 U.S.C. 7412(b)(1), excluding
caprolactam (CAS number 105602) as provided by Sec. 63.60, for each
waste to be burned. You must base this specification on the degree of
difficulty of incineration of the organic constituents in the waste and
on their concentration or mass in the waste feed, considering the
results of waste analyses or other data and information.
(d) Significant figures. The emission limits provided by paragraphs
(a) and (b) of this section are presented with two significant figures.
Although you must perform intermediate calculations using at least
three significant figures, you may round the resultant emission levels
to two significant figures to document compliance.

PART 264--STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE
TREATMENT, STORAGE, AND DISPOSAL FACILITIES

1. The authority citation for part 264 continues to read as follows:

Authority: 42 U.S.C. 6905, 6912(a), 6924, 6925, 6927, 6928(h), and 6974.

[[Page 21383]]

2. Section 264.340 is amended by revising the first sentence of
paragraph (b)(1) and adding paragraph (b)(5) to read as follows:

Sec. 264.340 Applicability.

* * * * *
(b) * * * (1) Except as provided by paragraphs (b)(2) through
(b)(5) of this section, the standards of this part no longer apply when
an owner or operator demonstrates compliance with the maximum
achievable control technology (MACT) requirements of part 63, subpart
EEE, of this chapter by conducting a comprehensive performance test and
submitting to the Administrator a Notification of Compliance under
Sec. Sec. 63.1207(j) and 63.1210(d) of this chapter documenting
compliance with the requirements of part 63, subpart EEE, of this
chapter. * * *
* * * * *
(5) The particulate matter standard of Sec. 264.343(c) remains in
effect for incinerators that elect to comply with the alternative to
the particulate matter standard of Sec. 63.1219(e) of this chapter.
* * * * *

PART 265--INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF
HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES

1. The authority citation for part 265 continues to read as follows:

Authority: 42 U.S.C. 6905, 6906, 6912, 6922, 6923, 6924, 6925,
6935, 6936, and 6937.

2. Section 265.340 is amended by revising paragraph (b)(1) to read
as follows:

Sec. 265.340 Applicability.

PART 266--STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES
AND SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES

1. The authority citation for part 266 continues to read as follows:

Authority: 42 U.S.C. 1006, 2002(a), 3001-3009, 3014, 6905, 6906,
6912, 6921, 6922, 6924-6927, 6934, and 6937.

2. Section 266.100 is amended by revising the first sentence of
paragraph (b)(1) and adding paragraph (b)(3) to read as follows:

Sec. 266.100 Applicability.

* * * * *
(b) * * * (1) Except as provided by paragraphs (b)(2) and (b)(3) of
this section, the standards of this part no longer apply when an owner
or operator demonstrates compliance with the maximum achievable control
technology (MACT) requirements of part 63, subpart EEE, of this chapter
by conducting a comprehensive performance test and submitting to the
Administrator a Notification of Compliance under Sec. Sec. 63.1207(j)
and 63.1210(d) of this chapter documenting compliance with the
requirements of part 63, subpart EEE, of this chapter. * * *
* * * * *
(3) If you own or operate a boiler or hydrochloric acid furnace
that is an area source under Sec. 63.2 of this chapter and you elect
not to comply with the emission standards under Sec. Sec. 63.1216,
63.1217, and 63.1218 of this chapter for particulate matter,
semivolatile and low volatile metals, and total chlorine, you also
remain subject to:
(i) Section 266.105--Standards to control particulate matter;
(ii) Section 266.106--Standards to control metals emissions, except
for mercury; and
(iii) Section 266.107--Standards to control hydrogen chloride and
chlorine gas.
* * * * *

PART 270--EPA ADMINISTERED PERMIT PROGRAMS: THE HAZARDOUS WASTE
PERMIT PROGRAM

1. The authority citation for part 270 continues to read as follows:

Authority: 42 U.S.C. 6905, 6912, 6924, 6925, 6927, 6939, and 6974.

2. Section 270.10 is amended by adding paragraph (l) to read as follows:

Sec. 270.10 General application requirements.

* * * * *
(l) If the Director concludes that there is reason to believe that
compliance with the standards in 40 CFR part 63, subpart EEE alone may
not be protective of human health or the environment, the Director
shall require additional information or assessment(s) that the Director
determines are necessary to ensure protection of human health and the
environment. The Director also may require a permittee or an applicant
to provide information necessary to determine whether such an
assessment(s) should be required.
3. Section 270.19 is amended by revising paragraph (e) to read as
follows:

Sec. 270.19 Specific part B information requirements for
incinerators.

* * * * *
(e) When an owner or operator demonstrates compliance with the air
emission standards and limitations in part 63, subpart EEE, of this
chapter (i.e., by conducting a comprehensive performance test and
submitting a Notification of Compliance under Sec. Sec. 63.1207(j) and
63.1210(d) of this chapter documenting compliance with all applicable
requirements of part 63, subpart EEE, of this chapter), the
requirements of this section do not apply, except those provisions the
Director determines are necessary to ensure compliance with Sec. Sec.
264.345(a) and 264.345(c) of this chapter if you elect to comply with
Sec. 270.235(a)(1)(i) to minimize emissions of toxic compounds from
startup, shutdown, and malfunction events. Nevertheless, the Director
may apply the provisions of this section, on a case-by-case basis, for
purposes of information collection in accordance with Sec. Sec.
270.10(k), 270.10(l), 270.32(b)(2), and 270.32(b)(3) of this chapter.
3. Section 270.22 is amended by revising the introductory text to
read as follows:

Sec. 270.22 Specific part B information requirements for boilers and
industrial furnaces burning hazardous waste.

When an owner or operator of a cement kiln, lightweight aggregate
kiln, solid fuel-fired boiler, liquid fuel-fired boiler, or
hydrochloric acid production furnace demonstrates compliance with the
air emission standards and limitations in part 63, subpart EEE, of this
chapter (i.e., by conducting a comprehensive performance test and
submitting a Notification of Compliance under Sec. Sec. 63.1207(j) and
63.1210(d) of this chapter documenting compliance with all applicable
requirements of part 63, subpart EEE, of this chapter), the
requirements of this section do not apply. The requirements of this
section

[[Page 21384]]

do apply, however, if the Director determines certain provisions are
necessary to ensure compliance with Sec. Sec. 266.102(e)(1) and
266.102(e)(2)(iii) of this chapter if you elect to comply with Sec.
270.235(a)(1)(i) to minimize emissions of toxic compounds from startup,
shutdown, and malfunction events; or if you are an area source and
elect to comply with the Sec. Sec. 266.105, 266.106, and 266.107
standards and associated requirements for particulate matter, hydrogen
chloride and chlorine gas, and non-mercury metals; or the Director
determines certain provisions apply, on a case-by-case basis, for
purposes of information collection in accordance with Sec. Sec.
270.10(k), 270.10(l), 270.32(b)(2), and 270.32(b)(3).
* * * * *
4. Section 270.32 is amended by adding paragraph (b)(3) to read as
follows:

Sec. 270.32 Establishing permit conditions.

* * * * *
(b) * * *
(3) If, as the result of an assessment(s) or other information, the
Administrator or Director determines that conditions are necessary in
addition to those required under 40 CFR parts 63, subpart EEE, 264 or
266 to ensure protection of human health and the environment, he shall
include those terms and conditions in a RCRA permit for a hazardous
waste combustion unit.
* * * * *
5. Section 270.42 is amended by:
a. Revising paragraph (j)(1).
b. Redesignating paragraph (j)(2) as (j)(3).
c. Adding new paragraph (j)(2).
d. Adding new paragraph (k); and
e. Adding a new entry 10 in numerical order in the table under
section L of Appendix I.
The revisions and additions reads as follows:

Sec. 270.42 Permit modification at the request of the permittee.

* * * * *
(j) * * *
(1) Facility owners or operators must have complied with the
Notification of Intent to Comply (NIC) requirements of 40 CFR 63.1210
that were in effect prior to October 11, 2000, (See 40 CFR part 63
Sec. Sec. 63.1200-63.1499 revised as of July 1, 2000) in order to
request a permit modification under this section for the purpose of
technology changes needed to meet the 40 CFR 63.1203, 63.1204, and
63.1205 standards.
(2) Facility owners or operators must comply with the Notification
of Intent to Comply (NIC) requirements of 40 CFR 63.1210(b) and 63.1212
before a permit modification can be requested under this section for
the purpose of technology changes needed to meet the 40 CFR 63.1215,
63.1216, 63.1217, 63.1218, 63.1219, 63.1220, and 63.1221 standards
promulgated on [date of publication of the final rule in the Federal
Register].
* * * * *
(k) Waiver of RCRA permitting requirements in support of transition
to the part 63 MACT standards. (1) You may request to have specific
RCRA operating and emissions limits waived by submitting a Class 1
permit modification request under Appendix I of this section, section
L(10). You must:
(i) Identify the specific RCRA permit operating and emissions
limits which you are requesting to waive;
(ii) Provide an explanation of why the changes are necessary in
order to minimize or eliminate conflicts between the RCRA permit and
MACT compliance; and
(iii) Discuss how the revised provisions will be sufficiently protective.
(2) To request this modification in conjunction with MACT
performance testing where permit limits may only be waived during
actual test events and pretesting, as defined under 40 CFR
63.1207(h)(2)(i) and (ii), for an aggregate time not to exceed 720
hours of operation (renewable at the discretion of the Administrator)
you must:
(i) Demonstrate that your site-specific emissions test plan and
continuous monitoring system performance evaluation test plan have been
submitted and approved by the Administrator as required in 40 CFR
63.1207(e), and
(ii) Submit your modification request upon approval of your test plan.
(3) The Director shall approve or deny the request within 30 days
of receipt of the request. The Director may, at his or her discretion,
extend this 30 day deadline one time for up to 30 days by notifying the
facility owner or operator.
* * * * *

Appendix I to Sec. 270.42--Classification of Permit Modification
------------------------------------------------------------------------
Modifications Class
------------------------------------------------------------------------

* * * * *
10. Changes to RCRA permit provisions needed to support \1\ 1
transition to 40 CFR part 63 (Subpart EEE--National Emission
Standards for Hazardous Air Pollutants From Hazardous Waste
Combustors), provided the procedures of Sec. 270.42(k) are
followed.......................................................

* * * * *
------------------------------------------------------------------------
\1\ Class 1 modifications requiring prior Agency approval.

6. Section 270.62 is amended by revising the introductory text to
read as follows:

Sec. 270.62 Hazardous waste incinerator permits.

When an owner or operator demonstrates compliance with the air
emission standards and limitations in part 63, subpart EEE, of this
chapter (i.e., by conducting a comprehensive performance test and
submitting a Notification of Compliance under Sec. Sec. 63.1207(j) and
63.1210(d) of this chapter documenting compliance with all applicable
requirements of part 63, subpart EEE, of this chapter), the
requirements of this section do not apply, except those provisions the
Director determines are necessary to ensure compliance with Sec. Sec.
264.345(a) and 264.345(c) of this chapter if you elect to comply with
Sec. 270.235(a)(1)(i) to minimize emissions of toxic compounds from
startup, shutdown, and malfunction events. Nevertheless, the Director
may apply the provisions of this section, on a case-by-case basis, for
purposes of information collection in accordance with Sec. Sec.
270.10(k), 270.10(l), 270.32(b)(2), and 270.32(b)(3) of this chapter.
* * * * *
7. Section 270.66 is amended by revising the introductory text to
read as follows:

Sec. 270.66 Permits for boilers and industrial furnaces burning
hazardous waste.

[[Page 21385]]

this chapter if you elect to comply with Sec. 270.235(a)(1)(i) to
minimize emissions of toxic compounds from startup, shutdown, and
malfunction events; or if you are an area source and elect to comply
with the Sec. Sec. 266.105, 266.106, and 266.107 standards and
associated requirements for particulate matter, hydrogen chloride and
chlorine gas, and non-mercury metals; or the Director determines
certain provisions apply, on a case-by-case basis, for purposes of
information collection in accordance with Sec. Sec. 270.10(k),
270.10(l), 270.32(b)(2), and 270.32(b)(3).
* * * * *
8. Section 270.235 is amended by:
a. Revising paragraphs (a)(1) introductory text and (a)(2)
introductory text.
b. Revising paragraphs (b)(1) introductory text and (b)(2).
The revisions read as follows:

Sec. 270.235 Options for incinerators, cement kilns, lightweight
aggregate kilns, solid fuel-fired boilers, liquid fuel-fired boilers
and hydrochloric acid production furnaces to minimize emissions from
startup, shutdown, and malfunction events.

(a) * * * (1) Revisions to permit conditions after documenting
compliance with MACT. The owner or operator of a RCRA-permitted
incinerator, cement kiln, lightweight aggregate kiln, solid fuel-fired
boiler, liquid fuel-fired boiler, or hydrochloric acid production
furnace may request that the Director address permit conditions that
minimize emissions from startup, shutdown, and malfunction events under
any of the following options when requesting removal of permit
conditions that are no longer applicable according to Sec. Sec.
264.340(b) and 266.100(b) of this chapter:
* * * * *
(2) Addressing permit conditions upon permit reissuance. The owner
or operator of an incinerator, cement kiln, lightweight aggregate kiln,
solid fuel-fired boiler, liquid fuel-fired boiler, or hydrochloric acid
production furnace that has conducted a comprehensive performance test
and submitted to the Administrator a Notification of Compliance
documenting compliance with the standards of part 63, subpart EEE, of
this chapter may request in the application to reissue the permit for
the combustion unit that the Director control emissions from startup,
shutdown, and malfunction events under any of the following options:
* * * * *
(b) * * * (1) Interim status operations. In compliance with
Sec. Sec. 265.340 and 266.100(b), the owner or operator of an
incinerator, cement kiln, lightweight aggregate kiln, solid fuel-fired
boiler, liquid fuel-fired boiler, or hydrochloric acid production
furnace that is operating under the interim status standards of part
265 or 266 of this chapter may control emissions of toxic compounds
during startup, shutdown, and malfunction events under either of the
following options after conducting a comprehensive performance test and
submitting to the Administrator a Notification of Compliance
documenting compliance with the standards of part 63, subpart EEE, of
this chapter.
* * * * *
(2) Operations under a subsequent RCRA permit. When an owner or
operator of an incinerator, cement kiln, lightweight aggregate kiln,
solid fuel-fired boiler, liquid fuel-fired boiler, or hydrochloric acid
production furnace that is operating under the interim status standards
of parts 265 or 266 of this chapter submits a RCRA permit application,
the owner or operator may request that the Director control emissions
from startup, shutdown, and malfunction events under any of the options
provided by paragraphs (a)(2)(i), (a)(2)(ii), or (a)(2)(iii) of this
section.
* * * * *

PART 271--REQUIREMENTS FOR AUTHORIZATION OF STATE HAZARDOUS WASTE PROGRAMS

1. The authority citation for part 271 continues to read as follows:

Authority: 42 U.S.C. 6905, 6912(a), and 6926.

2. Section 271.1(j) is amended by adding the following entry to
Table 1 in chronological order by date of publication in the Federal
Register, to read as follows:

Sec. 271.1 Purpose and scope.

* * * * *
(j) * * *

Table 1.--Regulations Implementing the Hazardous and Solid Waste Amendments of 1984
----------------------------------------------------------------------------------------------------------------
Federal Register
Promulgation date Title of regulation reference Effective date
----------------------------------------------------------------------------------------------------------------

* * * * * * *
Insert date of publication of final Standards for Hazardous [Insert FR page numbers [Insert date of
rule in the Federal Register (FR)]. Air Pollutants for of final rule]. publication of final
Hazardous Waste rule].
Combustors.
----------------------------------------------------------------------------------------------------------------

[FR Doc. 04-7858 Filed 4-19-04; 8:45 am]
BILLING CODE 6560-50-P

Notices For
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National Emission Standards for Hazardous Air Pollutants: Proposed Standards for Hazardous Air Pollutants for Hazardous Waste Combustors (Phase I Final Replacement Standards and Phase II)

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