National Emission Standards for Hazardous Air Pollutants: Final
Standards for Hazardous Air Pollutants for Hazardous Waste Combustors
(Phase I Final Replacement Standards and Phase II)
[Federal Register: October 12, 2005 (Volume 70, Number 196)]
[Rules and Regulations]
[Page 59401-59450]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr12oc05-25]
[[Page 59402]]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 9, 63, 260, 264, 265, 266, 270 and 271
[FRL-7971-8]
RIN 2050-AE01
National Emission Standards for Hazardous Air Pollutants: Final
Standards for Hazardous Air Pollutants for Hazardous Waste Combustors
(Phase I Final Replacement Standards and Phase II)
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This action finalizes national emission standards (NESHAP) for
hazardous air pollutants for hazardous waste combustors (HWCs):
hazardous waste burning incinerators, cement kilns, lightweight
aggregate kilns, industrial/commercial/institutional boilers and
process heaters, and hydrochloric acid production furnaces. EPA has
identified HWCs as major sources of hazardous air pollutant (HAP)
emissions. These standards implement section 112(d) of the Clean Air
Act (CAA) by requiring hazardous waste combustors to meet HAP emission
standards reflecting the performance of the maximum achievable control
technology (MACT).
The HAP emitted by HWCs 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 to the
lung, skin, and mucus membranes, effects on the central nervous system,
kidney damage, and cancer. The adverse health effects associated with
exposure to these specific HAP are further described in the preamble.
For many HAP, these findings have only been shown with concentrations
higher than those typically in the ambient air.
This action also presents our decision regarding the February 28,
2002 petition for rulemaking submitted by the Cement Kiln Recycling
Coalition, relating to EPA's implementation of the so-called omnibus
permitting authority under section 3005(c) of the Resource Conservation
and Recovery Act (RCRA). That section requires that each permit issued
under RCRA contain such terms and conditions as permit writers
determine to be necessary to protect human health and the environment.
In that petition, the Cement Kiln Recycling Coalition requested 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: The final rule is effective December 12, 2005. The incorporation
by reference of Method 0023A into Sec. 63.14 is approved by the
Director of the Federal Register as of December 12, 2005.
ADDRESSES: The official public docket is the collection of materials
that is available for public viewing at the Office of Air and Radiation
Docket and Information Center (Air Docket) in the EPA Docket Center,
Room B-102, 1301 Constitution Ave., NW., Washington, DC.
FOR FURTHER INFORMATION CONTACT: For more information concerning
applicability and rule determinations, contact your State or local
representative or appropriate EPA Regional Office representative. For
information concerning rule development, contact Michael Galbraith,
Waste Treatment Branch, Hazardous Waste Minimization and Management
Division, (5302W), U.S. EPA, 1200 Pennsylvania Avenue, NW., Washington
DC 20460, telephone number (703) 605-0567, fax number (703) 308-8433,
electronic mail address galbraith.michael@epa.gov.
SUPPLEMENTARY INFORMATION:
Regulated Entities
The promulgation of the final rule would affect the following North
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 hazardous
waste as defined in the final rule.
562211 4953 Incinerator, hazardous waste
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 entities 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.
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
[[Page 59403]]
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
[mu]g/dscm micrograms per dry standard cubic meter
U.S.C. United States Code
Table of Contents
Part One: Background and Summary
I. What Is the Statutory Authority for this Standard?
II. What Is the Regulatory Development Background of the Source
Categories in the Final Rule?
A. Phase I Source Categories
B. Phase II Source Categories
III. How Was the Final Rule Developed?
IV. What Is the Relationship Between the Final Rule and Other MACT
Combustion Rules?
V. What Are the Health Effects Associated with Pollutants Emitted by
Hazardous Waste Combustors?
Part Two: Summary of the Final Rule
I. What Source Categories and Subcategories Are Affected by the
Final Rule?
II. What Are the Affected Sources and Emission Points?
III. What Pollutants Are Emitted and Controlled?
IV. Does the Final Rule Apply to Me?
V. What Are the Emission Limitations?
VI. What Are the Testing and Initial Compliance Requirements?
A. Compliance Dates
B. Testing Requirements
C. Initial Compliance Requirements
VII. What Are the Continuous Compliance Requirements?
VIII. What Are the Notification, Recordkeeping, and Reporting Requirements?
IX. What Is the Health-Based Compliance Alternative for Total
Chlorine, and How Do I Demonstrate Eligibility?
A. Overview
B. HCl-Equivalent Emission Rates
C. Eligibility Demonstration
D. Assurance that the 1-Hour HCl-Equivalent Emission Rate Will
Not Be Exceeded
E. Review and Approval of Eligibility Demonstrations
F. Testing Requirements
G. Monitoring Requirements
H. Relationship Among Emission Rates, Emission Rate Limits, and
Feedrate Limits
I. Changes
X. Overview on Floor Methodologies
Part Three: What Are the Major Changes Since Proposal?
I. Database
A. Hazardous Burning Incinerators
B. Hazardous Waste Cement Kilns
C. Hazardous Waste Lightweight Aggregate Kilns
D. Liquid Fuel Boilers
E. HCl Production Furnaces
F. Total Chlorine Emissions Data Below 20 ppmv
II. Emission Limits
A. Incinerators
B. Hazardous Waste Burning Cement Kilns
C. Hazardous Waste Burning Lightweight Aggregate Kilns
D. Solid Fuel Boilers
E. Liquid Fuel Boilers
F. Hydrochloric Acid Production Furnaces
G. Dioxin/Furan Testing for Sources Not Subject to a Numerical Standard
III. Statistics and Variability
A. Using Statistical Imputation to Address Variability of
Nondetect Values
B. Degrees of Freedom when Imputing a Standard Deviation Using
the Universal Variability Factor for Particulate Matter Controlled
by a Fabric Filter
IV. Compliance Assurance for Fabric Filters, Electrostatic
Precipitators, and Ionizing Wet Scrubbers
V. Health-Based Compliance Alternative for Total Chlorine
Part Four: What Are the Responses to Major Comments?
I. Database
A. Revisions to the EPA's Hazardous Waste Combustor Data Base
B. Use of Data from Recently Upgraded Sources
C. Correction of Total Chlorine Data to Address Potential Bias
in Stack Measurement Method
D. Mercury Data for Cement Kilns
E. Mercury Data for Lightweight Aggregate Kilns
F. Incinerator Database
II. Affected Sources
A. Area Source Boilers and Hydrochloric Acid Production Furnaces
B. Boilers Eligible for the RCRA Low Risk Waste Exemption
C. Mobile Incinerators
III. Floor Approaches
A. Variability
B. SRE/Feed Methdology
C. Air Pollution Control Technology Methodologies for the
Particulate Matter Standard and for the Total Chlorine Standard for
Hydrochloric Acid Production Furnaces
D. Format of Standards
E. Standards Can Be No Less Stringent Than the Interim Standards
F. How Can EPA's Approach to Assessing Variability and its
Ranking Methodologies be Reasonable when they Result in Standards
Higher than the Interim Standards?
IV. Use of Surrogates
A. Particulate Matter as Surrogate for Metal HAP
B. Carbon Monoxide/Hydrocarbons and DRE as Surrogates for Dioxin/Furan
C. Use of Carbon Monoxide and Total Hydrocarbons as Surrogate
for Non-Dioxin Organic HAP
V. Additional Issues Relating to Variability and Statistics
A. Data Sets Containing Nondetects
B. Using Statistical Imputation to Address Variability of
Nondetect Values
C. Analysis of Variance Procedures to Assess Subcategorization
VI. Emission Standards
A. Incinerators
B. Cement Kilns
C. Lightweight Aggregate Kilns
D. Liquid Fuel Boilers
E. General
VII. Health-Based Compliance Alternative for Total Chlorine
A. Authority for Health-Based Compliance Alternatives
B. Implementation of the Health-Based Standards
C. National Health-Based Standards for Cement Kilns.
VIII. Implementation and Compliance
A. Compliance Assurance Issues for both Fabric Filters and
Electrostatic Precipitators (and Ionizing Wet Scrubbers)
B. Compliance Assurance Issues for Fabric Filters
C. Compliance Issues for Electrostatic Precipitators and
Ionizing Wet Scrubbers
D. Fugitive Emissions
E. Notification of Intent to Comply and Compliance Progress Report
F. Startup, Shutdown, and Malfunction Plan
G. Public Notice of Test Plans
H. Using Method 23 Instead of Method 0023A
I. Extrapolating Feedrate Limits for Compliance with the Liquid
Fuel Boiler Mercury and Semivolatile Metal Standards
J. Temporary Compliance with Alternative, Otherwise Applicable
MACT Standards
K. Periodic DRE Testing and Limits on Minimum Combustion Chamber
Temperature for Cement Kilns
L. One Time Dioxin and Furan Test for Sources Not Subject to a
Numerical Limit for Dioxin and Furan
M. Miscellaneous Compliance Issues
IX. Site-Specific Risk Assessment under RCRA
A. What Is the Site-Specific Risk Assessment Policy?
B. Why Might SSRAs Continue To Be Necessary for Sources
Complying With Phase 1 Replacement Standards and Phase 2 Standards?
C. What Changes Are EPA Finalizing With Respect To the Site-
Specific Risk Assessment Policy?
D. How Will the New SSRA Regulatory Provisions Work?
E. What Were Commenters' Reactions to EPA's Proposed Decision
Not to Provide National Criteria for Determining When an SSRA Is or
Is Not Necessary?
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F. What Are EPA's Responses to the Cement Kiln Recycling
Coalition's Comments on the Proposal and What is EPA's Final
Decision on CKRC's Petition?
X. Permitting
A. What is the Statutory Authority for the RCRA Requirements
Discussed in this Section?
B. Did Commenters Express any Concerns Regarding the Current
Permitting Requirements?
C. Are There Any Changes to the Proposed Class 1 Permit
Modification Procedure?
D. What Permitting Approach Is EPA Finalizing for New Units?
E. What Other Permitting Requirements Were Discussed In the Proposal?
Part Five: What Are the CAA Delegation Clarifications and RCRA State
Authorization Requirements?
I. Authority for this Rule.
II. CAA Delegation Authority.
III. Clarifications to CAA Delegation Provisions for Subpart EEE.
A. Alternatives to Requirements.
B. Alternatives to Test Methods.
C. Alternatives to Monitoring.
D. Alternatives to Recordkeeping and Reporting.
E. Other Delegation Provisions
IV. RCRA State Authorization and Amendments To the RCRA Regulations.
Part Six: Impacts of the Final 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. What Are the Economic Impacts?
A. Market Exit Estimates
B. Waste Reallocations
VI. What Are the Social Costs and Benefits of the Final Rule?
A. Combustion Market Overview
B. Baseline Specification
C. Analytical Methodology and Findings--Social Cost Analysis
D. Analytical Methodology and Findings--Benefits Assessment
Part Seven: How Does the Final Rule Meet the RCRA Protectiveness Mandate?
I. Background
II. Evaluation of Protectiveness
Part Eight: Statutory and Executive Order Reviews
I. Executive Order 12866: Regulatory Planning and Review
II. Paperwork Reduction Act
III. Regulatory Flexibility Act
IV. Unfunded Mandates Reform Act of 1995
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 Risks and Safety Risks
VIII. Executive Order 13211: Actions Concerning Regulations 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
Part One: Background and Summary
I. 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).
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).
Hazardous waste incinerators, Portland cement plants, clay products
manufacturing (including 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 these sources may reasonably be anticipated to emit one or more of
the 186 listed HAP in quantities sufficient to designate them as major
sources.
II. What Is the Regulatory Development Background of the Source
Categories in the Final Rule?
Today's notice finalizes standards for controlling emissions of HAP
from hazardous waste combustors: incinerators, cement kilns,
lightweight aggregate kilns, boilers, process heaters \1\, and
hydrochloric acid production furnaces that burn hazardous waste. 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.
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\1\ A process heater meets the RCRA definition of a boiler.
Therefore, process heaters that burn hazardous wastes are covered
under subpart EEE as boilers, and are discussed as such in
subsequent parts of the preamble.
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A. 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 hazardous waste burning 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 assure
control necessary to protect human health and the environment, the
applicable RCRA standard. See RCRA section 3004 (a) and (q).
The Phase I source categories also are subject to standards under
the Clean Air Act. We promulgated standards for Phase I sources on
September 30, 1999 (64 FR 52828). This final rule is referred to in
this preamble 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 on a source-by-source basis in a RCRA permit if necessary 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 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, for new sources,
(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.
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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
adverse consequences that would result from the regulatory gap
resulting from no standards being in place. Id. at 6793, 6795-96; see
also 69 FR at 21217 (April 20, 2004). EPA also entered into a
settlement agreement, enforceable by the Court of Appeals, to issue
final standard conforming to the Court's mandate by June 14, 2005. That
date has since been extended to September 14, 2005.
B. 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 also have entered
into a judicially enforceable consent decree with Sierra Club that
requires EPA to promulgate MACT standards for the Phase II sources by
June 14, 2005, since extended to September 14, 2005--the same date that
(for independent reasons) is required for the replacement standards for
Phase I sources.
III. How Was the Final Rule Developed?
We proposed standards for HWCs on April 20, 2004 (69 FR 21197). The
public comment period closed on July 6, 2004. In addition, on February
4, 2005, we requested certain key commenters to comment by email on a
limited number of issues arising from public comments on the proposed
rule. The comment period for those issues closed on March 7, 2005.
We received approximately 100 public comment letters on the
proposed rule and the subsequent direct request for comments. Comments
were submitted by owner/operators of HWCs, trade associations, state
regulatory agencies and their representatives, and environmental
groups. Today's final rule reflects our consideration of all of the
comments and additional information we received. Major public comments
on the proposed rule along with our responses, are summarized in this
preamble.
IV. What Is the Relationship Between the Final Rule and Other MACT
Combustion Rules?
The amendments to the Subpart EEE, Part 63, standards for hazardous
waste combustors 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 final rule, however,
also amends 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. 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).
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 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,
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.\2\ 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 and/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.\3\ 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).
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\2\ Note, however, that fugitive emissions attributable to the
combustion of hazardous waste from the combustion device are
regulated pursuant to Subpart EEE.
\3\ Hydrochloric acid production furnaces that combust hazardous
waste are also affected sources subject to Subpart NNNNN if they
produce a liquid acid product that contains greater than 30%
hydrochloric acid.
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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
[[Page 59406]]
EEE requirements. However, even as an affected source, the emission
standards or operating limits 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.
V. What Are the Health Effects Associated With Pollutants Emitted by
Hazardous Waste Combustors?
Today's final 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 final rule show that metals, hydrogen chloride and chlorine gas,
dioxins and furans, and other organic compounds are emitted from
hazardous waste combustors. The HAP that would 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.
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 an antimony
processing facilities. Similar effects on the heart, lungs, and
reproductive system have been observed in laboratory animals.
EPA 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.\4\ 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, the International
Agency for Research on Cancer in an earlier evaluation, concluded that
antimony trioxide is ``possibly carcinogenic to humans'' (Group 2B).
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\4\ See ``Evaluating THe Carcinogenicity of Antimony,'' Rish
Assessment Issue Paper (98-030/07-26-99), Superfund Technical Support
Center, National Center for Environmental Assessment, July 26, 1999.
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Arsenic
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
Chronic inhalation exposure of humans to high levels of beryllium
has been reported to cause chronic beryllium disease (berylliosis), in
which granulomatous (noncancerous) lesions develop in the lung.
Inhalation exposure to high levels of beryllium has been demonstrated
to cause lung cancer in rats and monkeys. Human studies are limited,
but suggest a causal relationship between beryllium exposure and an
increased risk of lung cancer. We have classified beryllium as a Group
B1, probable human carcinogen, when inhaled; data are inadequate to
determine whether beryllium is carcinogenic when ingested.
Cadmium
Chronic 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
Chlorine is an 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. No information is available on the carcinogenic effects of
chlorine in humans from inhalation exposure. A National Toxicology
Program (NTP) study showed no evidence of carcinogenic activity in male
rats or male and female mice, and equivocal evidence in female rats,
from ingestion of chlorinated water. The EPA has not classified
chlorine for potential carcinogenicity. In the absence of specific
scientific evidence to the contrary, it is the Agency's policy to
classify noncarcinogenic effects as threshold effects. RfC development
is the default approach for threshold (or nonlinear) effects.
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 inhalation exposures.
Bronchitis, decreases pulmonary function, pneumonia, and other
respiratory effects have been noted from chronic high does exposure in
occupational settings due to chromium VI. 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
[[Page 59407]]
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 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, especially copper. Cobalt
has been widely reported to cause respiratory effects in humans exposed
by inhalation, including respiratory irritation, wheezing, asthma, and
pneumonia. Cardiomyopathy (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 as 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
(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 has
classified cobalt as a confirmed animal carcinogen with unknown
relevance to humans (category A3). An EPA assessment concludes that
under EPA's cancer guidelines, cobalt would be considered likely to be
carcinogenic to humans.\5\
---------------------------------------------------------------------------
\5\ 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. This is a provisional
EPA assessment that has been externally peer reviewed but has not
yet been incorporated in IRIS.
---------------------------------------------------------------------------
Dioxins and Furans
Exposures to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and
related compounds at levels 10 times or less above those modeled to
approximate average background exposure have resulted in adverse non-
cancer health effects in animals. This statement is based on
assumptions about the toxic equivalent for these compounds, for which
there is acknowledged uncertainty. 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.\6\ 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.\7\
---------------------------------------------------------------------------
\6\ 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.
\7\ The U.S. Department of Health and Human Services, National
Toxicology Program 9th Report on Carcinogens, Revised January 2001.
---------------------------------------------------------------------------
The chemical and environmental stability of dioxins and their
tendency to accumulate in fat have resulted in their detection within
many ecosystems. In the United States and elsewhere, accidental
contamination of the environment by 2,3,7,8-TCDD has resulted in deaths
in many species of wildlife and domestic animals.\8\ High residues of
this compound in fish have resulted in closing rivers to fishing.
Laboratory studies with birds, mammals, aquatic organisms, and other
species have demonstrated that exposure to 2,3,7,8-TCDD can result in
acute and delayed mortality as well as carcinogenic, teratogenic,
mutagenic, histopathologic, immunotoxic, and reproductive effects,
depending on dose received, which varied widely in the experiments.\9\
---------------------------------------------------------------------------
\8\ This does not necessarily apply in regard to laboratory
testing, which tend to use 2,3,7,8 TCDD as the test compound.
\9\ Eisler, R. 1986. Dioxin hazards to fish, wildlife, and
invertebrates: a synoptic review. U.S. Fish and Wildlife Service
Biological Report. 85(1.8).
---------------------------------------------------------------------------
Hydrogen chloride/hydrochloric acid
Hydrogen chloride, also called hydrochloric acid, is corrosive to
the eyes, skin, and mucous membranes. 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. In the absence of specific scientific evidence to the
contrary, it is the Agency's policy to classify noncarcinogenic effects
as threshold effects. RfC development is the default approach for
threshold (or nonlinear) effects.
Lead
Lead can cause a variety of effects at low dose levels. Chronic
exposure to high levels of lead in humans results in effects on the
blood, central nervous system, 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 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
[[Page 59408]]
exposure to high levels of manganese by inhalation in humans results
primarily in central nervous system effects. Visual reaction time, hand
steadiness, and eye-hand coordination were affected in chronically-
exposed workers. 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 typically formed by biological
processes after mercury has precipitated from the air.
Chronic exposure to elemental mercury in humans also affects the
central nervous system, with effects such as increased excitability,
irritability, excessive shyness, and tremors. The EPA has not
classified elemental mercury with respect to cancer.
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 an essential element in some animal species, and it has
been suggested it may be essential for human nutrition. Nickel
dermatitis, consisting of itching of the fingers, hand and forearms, is
the most common effect in humans from chronic exposure to nickel.
Respiratory effects have also been reported in humans from inhalation
exposure to nickel. No information is available regarding the
reproductive of developmental effects of nickel in humans, but animal
studies have reported such effects, although a consistent dose-response
relationship has not been seen. Nickel forms released from industrial
boilers include soluble nickel compounds, nickel subsulfide, and nickel
carbonyl. Human and animal studies have reported an increased risk of
lung and nasal cancers from exposure to nickel refinery dusts and
nickel subsulfide. Animal studies of soluble nickel compounds i.e.,
nickel carbonyl) have reported lung tumors. The EPA has classified
nickel refinery subsulfide as a Group A, human carcinogen and nickel
carbonyl as a Group B2, probable human carcinogen.
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. Organic HAP also 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
Atmospheric particulate matter (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.
Exposure to particles can lead to a variety of serious health
effects. The largest particles do not get very far into the lungs, so
they tend to cause fewer harmful health effects. Fine particles pose
the greatest problems because they can get deep into the lungs.
Scientific studies show links between these small particles and
numerous adverse health effects. Epidemiological studies have shown a
significant correlation between elevated PM levels and premature
mortality. Other important effects associated with PM exposure include
aggravation of respiratory and cardiovascular disease (as indicated by
increased hospital admissions, emergency room visits, absences from
school or work, and restricted activity days), lung disease, decreased
lung function, asthma attacks, and certain cardiovascular problems.
Individuals particularly sensitive to PM exposure include older adults
and people with heart and lung disease.
This is only a partial summary of adverse health and environmental
effects associated with exposure to PM. Further information is found in
the 2004 Criteria Document for PM (``Air Quality Criteria for
Particulate Matter,'' EPA/600/P-99/002bF) and the 2005 Staff Paper for
PM (EPA, ``Review of the National Ambient Air Quality Standards for
Particulate Matter, Policy Assessment of Scientific and Technical
Information: OAQPS Staff Paper,'' (June 2005)).
Selenium
Selenium is a naturally occurring substance that is toxic at high
concentrations but is also a nutritionally essential element. Studies
of humans chronically exposed to high levels of selenium in food and
water have reported discoloration of the skin, pathological deformation
and loss of nails, loss of hair, excessive tooth decay and
discoloration, lack of mental alertness, and listlessness. The
consumption of high levels of selenium by pigs, sheep, and cattle has
been shown to interfere with normal fetal development and to produce
birth defects. Results of human and animal studies suggest that
supplementation with some forms of selenium may result in a reduced
incidence of several tumor types. One selenium compound, selenium
sulfide, is carcinogenic in animals exposed orally. We have classified
elemental selenium as a Group D, not classifiable as to human
carcinogenicity, and selenium sulfide as a Group B2, probable human
carcinogen.
Part Two: Summary of the Final Rule
I. What Source Categories and Subcategories Are Affected by the Final Rule?
Today's rule promulgates standards for controlling emissions of HAP
from hazardous waste combustors: incinerators, cement kilns,
lightweight aggregate kilns, boilers, and hydrochloric acid production
furnaces that burn hazardous waste. A description of each source
category can be found in the proposed rule (see 69 FR at 21207-08).
Hazardous waste burning incinerators, cement kilns, and lightweight
aggregate kilns are currently subject to 40 CFR part 63, subpart EEE,
National Emission Standards for Hazardous Air Pollutants (NESHAP).
Today's rule revises the emissions limits and certain compliance and
monitoring provisions of subpart EEE for these
[[Page 59409]]
source categories. The definitions of hazardous waste incinerator,
hazardous waste cement kiln, and hazardous waste lightweight aggregate
kiln appear at 40 CFR 63.1201(a).
Boilers that burn hazardous waste are also affected sources under
today's rule. The rule uses the RCRA definition of a boiler under 40
CFR 260.10 and includes industrial, commercial, and institutional
boilers as well as thermal units known as process heaters. Hazardous
waste burning boilers will continue to comply with the emission
standards found under 40 CFR part 266, subpart H (i.e., the existing
RCRA rules) until they demonstrate compliance with the requirements of
40 CFR part 63, subpart EEE, and, for permitted sources, subsequently
remove these requirements from their RCRA permit.
Finally, hydrochloric acid production furnaces that burn hazardous
waste are affected sources under today's rule. These furnaces are a
type of halogen acid furnace included in the definition of ``industrial
furnace'' defined at Sec. 260.10. Hydrochloric acid production
furnaces that burn hazardous waste will continue to comply with the
emission standards found under 40 CFR part 266, subpart H, until they
demonstrate compliance with 40 CFR part 63, subpart EEE, and, for
permitted sources, subsequently remove these requirements from their
RCRA permit.
II. What Are the Affected Sources and Emission Points?
Today's rule apply to each major and area source incinerator,
cement kiln, lightweight aggregate kiln, boiler, and hydrochloric acid
production furnace that burns hazardous waste.\10\ We note that only
major source boilers and hydrochloric acid production furnaces are
subject to the full suite of subpart EEE emission standards.\11\ The
emissions limits apply to each emission point (e.g., stack) where gases
from the combustion of hazardous waste are discharged or otherwise
emitted into the atmosphere. For facilities that have multiple
combustion gas discharge points, the emission limits generally apply to
each emission point. A cement kiln, for example, could be configured to
have dual stacks where the majority of combustion gases are discharged
though the main stack and other combustion gases emitted through a
separate stack, such as an alkali bypass stack. In that case, the
emission standards would apply separately to each of these stacks.\12\
---------------------------------------------------------------------------
\10\ A major source emits or has the potential to emit 10 tons
per year of any single hazardous air pollutant or 25 tons per year
or greater of hazardous air pollutants in the aggregate. An area
source is a source that is not a major source.
\11\ See Part Four, Section II.A for a discussion of the
standards that are applicable to area source boilers and
hydrochloric acid production furnaces.
\12\ We note that there is a provision that allows cement kilns
with dual stacks to average emissions on a flow-weighted basis to
demonstrate compliance with the metal and chlorine emission
standards. See Sec. Sec. 63.1204(e) and 63.1220(3).
---------------------------------------------------------------------------
III. What Pollutants Are Emitted and Controlled?
Hazardous waste combustors emit dioxin/furans, sometimes at high
levels depending on the design and operation of the emission control
equipment, and, for incinerators, depending on whether a waste heat
recovery boiler is used. All hazardous waste combustors can also 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. Hazardous waste burning
hydrochloric acid production furnaces, however, generally feed and emit
low levels of metal HAP.
All of these HAP metals (except for the volatile metal mercury) are
emitted as a portion of the particulate matter emitted by these
sources. Hazardous waste combustors can also emit high levels of
particulate matter, except that hydrochloric acid production furnaces
generally feed hazardous wastes with low ash content and consequently
emit low levels of particulate matter. A majority of particulate matter
emissions from hazardous waste combustors are in the form of fine
particulate. Particulate emissions from incinerators and liquid fuel-
fired boilers depend on the ash content of the hazardous 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 fine raw material entrained in the combustion gas. Thus, particulate
emissions from kilns depends on operating conditions that effect
entrainment of raw material, and the design and operation of the
emission control equipment.
IV. Does the Final Rule Apply to Me?
The final rule applies to you if you own or operate a hazardous
waste combustor--an incinerator, cement kiln, lightweight aggregate
kiln, boiler, or hydrochloric acid production facility that burns
hazardous waste. The final rule does not apply to a source that meets
the applicability requirements of Sec. 63.1200(b) for reasons
explained at 69 FR at 21212-13.
V. What Are the Emission Limitations?
You must meet the emission limits in Tables 1 and 2 of this
preamble for your applicable source category and subcategory. Standards
are corrected to 7 percent oxygen. As noted at proposal, we previously
promulgated requirements for carbon monoxide, total hydrocarbon, and
destruction and removal efficiency standards under subpart EEE for
incinerators, cement kilns, and lightweight aggregate kilns. We view
these standards as unaffected by the Court's vacature of the challenged
regulations in its decision of July 24, 2001. We are therefore not re-
promulgating and reopening consideration of these standards in today's
final rule, but are summarizing these standards in Tables 1 and 2 for
reader's convenience.\13\ See 69 FR at 21221, 21248, 21261 and 21274.
---------------------------------------------------------------------------
\13\ We are also republishing these standards, for reader's
convenience only, in the new replacement standard section for these
source categories. See Sec. 63.1219, Sec. 63.1220 and Sec. 673.1219.
---------------------------------------------------------------------------
Liquid fuel boilers equipped with dry air pollution control devices
are subject to different dioxin/furan emission standards than liquid
fuel boilers that are not equipped with dry air pollution control
devices.\14\ Liquid fuel boilers processing hazardous waste with a
heating value less than 10,000 BTU/lb must comply with the emission
concentration-based standards (expressed as mass of total HAP emissions
per volume of stack gas emitted) for mercury, semivolatile metals, low
volatile metals, and total chlorine. Liquid fuel boilers processing
hazardous waste with heating values greater than 10,000 BTU/lb must
comply with thermal emissions-based standards (expressed as mass of HAP
emissions attributable to the hazardous waste per million BTU input
from the hazardous waste) for those same pollutants. Low volatile metal
standards for liquid fuel boilers apply only to emissions of chromium,
whereas the low volatile metal standard for the other source categories
applies to the combined emissions of chromium, arsenic, and beryllium.
Semivolatile metal standards apply to the combined emissions of lead
and cadmium.
---------------------------------------------------------------------------
\14\ Liquid fuel boilers equipped with a wet air pollution
control device followed by a dry air pollution control device do not
meet the definition of a dry air pollution device.
---------------------------------------------------------------------------
For any of the source categories except hydrochloric acid production
[[Page 59410]]
furnaces, you may elect to comply with an alternative to the total
chlorine standard under which you would establish site-specific,
health-based emission limits for hydrogen chloride and chlorine based
on national exposure standards. This alternative chlorine standard is
discussed in part two, section IX and part four, section VII.
Incinerators and liquid and solid fuel boilers may elect to comply
with an alternative to the particulate matter standard that would limit
emissions of all the semivolatile metal HAPs and low volatile metal
HAPs. Under this alternative, the numerical emission limits for
semivolatile metal and low volatile metal emission HAP are identical to
the limitations included in Tables 1 and 2. However, for semivolatile
metals, the alternative standard applies to the combined emissions of
lead, cadmium, and selenium; for low volatile metals, the standard
applies to the combined emissions of chromium, arsenic, beryllium,
antimony, cobalt, manganese, and nickel. See Sec. 63.1219(e).
Table 1.--Summary of Emission Limits 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)..... 0.20 or 0.40 and 0.20 or 0.40 and 0.20 or rapid CO or HC and DRE 0.40 for dry APCD CO or HC and DRE
temperature temperature quench below standard as a sources; CO or HC standard as
control < control < 400[deg]F at kiln surrogate. and DRE standard surrogate.
400[deg]F at APCD 400[deg]F at APCD exit. as surrogate for
inlet \6\. inlet. others.
Mercury......................... 130 [mu]g/dscm.... Hazardous waste 120 hazardous 11 [mu]g/dscm..... 4.2E-5lb/MMBtu Total chlorine
feed restriction waste MTEC \11\ \2\, \5\ or 19 standard as
of 3.0 ppmw and feed restriction [mu]g/dscm \2\; surrogate.
120 [mu]g/dscm or 120 [mu]g/dscm depending on BTU
MTEC \11\; or 120 total emissions. content of
[mu]g/dscm total hazardous waste
emissions. \13\.
Particulate Matter.............. 0.013 gr/dscf \8\. 0.028 gr/dscf and 0.025 gr/dscf..... 0.030 gr/dscf \8\. 0.035 gr/dscf \8\. Total chlorine
20% opacity \12\. standard as
surrogate.
Semivolatile Metals (lead + 230 [mu]g/dscm.... 7.6 E-4 lbs/MMBtu 3.0E-4 lb/MMBtu 180 [mu]g/dscm.... 8.2 E-5 lb/MMBtu Total chlorine
cadmium). \5\ and 330 [mu]g/ \5\ and 250 [mu]g/ \2\, \5\ or 150 standard as
dscm \3\. dscm \3\. [mu]g/dscm \2\; surrogate.
depending on BTU
content of
hazardous waste
\13\.
Low Volatile Metals (arsenic + 92 [mu]g/dscm..... 2.1 E-5 lbs/MMBtu 9.5E-5 lb/MMBtu 380 [mu]g/dscm.... 1.26E-4 lbMMBtu Total chlorine
beryllium + chromium). \5\ and 56 [mu]g/ \5\ and 110 [mu]g/ \4\, \5\ or 370 standard as
dscm \3\. dscm \3\. [mu]g/dscm \4\; surrogate.
depending on BTU
content of
hazardous waste
\13\.
Total Chlorine (hydrogen 32 ppmv \7\....... 120 ppmv \7\...... 600 ppmv \7\...... 440 ppmv \7\...... 5.08E-2 lb/MMBtu 150 ppmv or
chloride + chlorine gas). \5\, \7\ or 31 99.923% system
ppmv \7\; removal
depending on BTU efficiency.
content of
hazardous waste
\13\.
Carbon Monoxide (CO) or 100 ppmv CO \9\ or See Note # 100 ppmv CO \9\ or (2) 100 ppmv CO \9\ or 10 ppmv HC
Hydrocarbons (HC). 10 ppmv HC. 10 below. 20 ppmv HC.
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 for solid and liquid fuel boilers apply only to major
sources. Particulate matter, semivolatile and low volatile metal standards for hydrochloric acid production furnaces apply only to major sources,
although area sources must still comply with the surrogate total chlorine standard to control mercury emissions.
\2\ Standard is based on normal emissions data, and is therefore expressed as an annual average emission limitation.
\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.
\5\ Standards expressed as mass of pollutant contributed by hazardous waste per million BTU contributed by the hazardous waste.
\6\ APCD means ``air pollution control device''.
\7\ Sources may elect to comply with site-specific risk-based emission limits for hydrogen chloride and chlorine gas
\8\ Sources may elect to comply with an alternative to the particulate matter standard.
\9\ Sources that elect to comply with the CO standard must demonstrate compliance with the HC standard during the comprehensive performance test that
demonstrates compliance with the destruction and removal efficiency requirement.
\10\ Kilns without a bypass: 20 ppmv HC or 100 ppmv CO \9\. Kilns with a bypass/mid-kiln sampling system: 10 ppmv HC or 100 ppmv CO9 in the bypass duct,
mid-kiln sampling system or bypass stack.
\11\ MTEC means ``maximum theoretical emission concentration'', and is equivalent to the feed rate divided by gas flow rate
\12\ The opacity standard does not apply to a source equipped with a bag leak detection system under 63.1206(c)(8) or a particulate matter detection
system under 63.1206(c)(9).
\13\ Emission concentration-based standards apply to sources processing hazardous waste with energy content less than 10,000 BTU/lb; thermal emission
standards apply to sources processing hazardous waste with energy content greater than 10,000 btu/lb.
[[Page 59411]]
Table 2.--Summary of Emission Limits for New or Reconstructed 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 and 0.20 or rapid CO or HC and DRE 0.40 for sources CO or THC and DRE
and/or WHB \5\ temperature quench < 400 standard as a with dry APCD; CO standard as a
sources; 0.20 for control < 400 [deg]F at kiln surrogate. or HC and DRE surrogate.
other sources. [deg]F at APCD exit. standard as a
inlet. surrogate for
other sources.
Mercury......................... 8.1 [mu]g/dscm.... Hazardous waste 120 hazardous 11 [mu]g/dscm..... 1.2E-6 lb/MMBtu 2 TCl as surrogate.
feed restriction waste MTEC \10\ 4 or 6.8 [mu]g/
of 1.9 ppmw and feed restriction dscm \2\;
120 [mu]g/dscm or 120 [mu]g/dscm depending on BTU
MTEC \10\; or 120 total emissions. content of
[mu]g/dscm total hazardous waste
emissions. \12\.
Particulate matter (gr/dscf).... 0.0015 \7\........ 0.0023 and 20% 0.0098............ 0.015 \7\......... 0.0087 \7\........ TCl as surrogate.
opacity \11\.
Semivolatile Metals (lead + 10 [mu]g/dscm..... 6.2E-5 lb/MMBtu 3.7 E-5 lb/MMBtu 180 [mu]g/dscm.... 6.2 E-6 lb/MMBtu 2 TCl as surrogate.
cadmium). \4\ and 180 [mu]g/ \4\ and 43 [mu]g/ 4 or 78 [mu]g/
dscm. dscm. dscm \2\;
depending on BTU
content of
hazardous waste
\12\.
Low Volatile Metals (arsenic + 23 [mu]g/dscm..... 1.5E-5 lb/MMBtu 3..3E-5 lb/MMBtu 190 [mu]g/dscm.... 1.41E-5lb/MMBtu 3 TCl as surrogate.
beryllium + chromium). \4\ and 54 [mu]g/ \4\ and 110 [mu]g/ 4 or 12 [mu]g/
dscm. dscm. dscm \3\;
depending on BTU
content of
hazardous waste
\12\.
Total Chlorine (Hydrogen 21 ppmv \6\....... 86 ppmv \6\....... 600 ppmv \6\...... 73 ppmv \6\....... 5.08E-2 lb/MMBtu 4 25 ppmv or 99.987%
chloride + chlorine gas). 6 or 31 ppmv \6\; SRE.
depending on BTU
content of
hazardous waste
\12\.
Carbon monoxide (CO) or 100 ppmv CO \8\ or See note < greek- 100 ppmv CO \8\ or 100 ppmv CO \8\ or 10 ppmv HC
Hydrocarbons (HC). 10 ppmv HC. i>9 below. 20 ppmv HC.
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 for solid and liquid fuel boilers apply only to major
sources. Particulate matter, semivolatile and low volatile metal standards for hydrochloric acid production furnaces apply only to major sources,
although area sources must still comply with the surrogate total chlorine standard to control mercury emissions.
\2\ Standard is based on normal emissions data, and is therefore expressed as an annual average emission limitation.
\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 expressed as mass of pollutant contributed by hazardous waste per million BTU contributed by the hazardous waste.
\5\ APCD means ``air pollution control device'', WHB means ``waste heat boiler''.
\6\ Sources may elect to comply with risk-based emission limits for hydrogen chloride and chlorine gas.
\7\ Sources may elect to comply with an alternative to the particulate matter standard.
\8\ Sources that elect to comply with the CO standard must demonstrate compliance with the THC standard during the comprehensive performance test that
demonstrates compliance with the destruction and removal efficiency requirement.
\9\ Greenfield kilns without a bypass: 20 ppmv HC or 100 ppmv CO \8\ and 50 ppmv HC. Greenfield kilns with a bypass/mid kiln sampling system: Main stack
standard of 50 ppmv HC and 10 ppmv HC or 100 ppmv CO \8\ in the bypass duct, mid-kiln sampling system or bypass stack. Greenfield kilns with a bypass/
mid-kiln sampling system: 10 ppmv HC or 100 ppmv CO \8\ in the bypass duct, mid-kiln sampling system or bypass stack; Non-greenfield kilns without a
bypass: 20 ppmv HC or 100 ppmv CO \8\. A greenfield kiln is a kiln whose construction commenced after April 19, 1996 at a plant site where a cement
kiln (whether burning hazardous waste or not) did not previously exist.
\10\ MTEC means ``maximum theoretical emission concentration'', and is equivalent to the feed rate divided by gas flow rate.
\11\ The opacity standard does not apply to a source equipped with a bag leak detection system under 63.1206(c)(8) or a particulate matter detection
system under 63.1206(c)(9).
\12\ Emission concentration-based standards apply to sources processing hazardous waste with energy content less than 10,000 BTU/lb; thermal emission
standards apply to sources processing hazardous waste with energy content greater than 10,000 btu/lb.
VI. What Are the Testing and Initial Compliance Requirements?
The testing and initial compliance requirements we promulgate today
for solid fuel boilers, liquid fuel boilers, and hydrochloric acid
production furnaces are identical to those that are applicable to
incinerators, cement kilns, and lightweight aggregate kilns at
Sec. Sec. 63.1206, 63.1207, and 63.1208. We note, however, that
today's final rule revises some of these requirements as they apply to
all or specific HWCs (e.g., one-time dioxin/furan test for sources not
subject to a numerical dioxin/furan standard; dioxin/furan stack test
method; hydrogen chloride and chlorine stack test methods)
We also discuss compliance and testing dates for incinerators,
cement kilns, and lightweight aggregate kilns as well. Even though we
are not repromulgating the compliance and testing requirements for
those source categories, those sources must demonstrate compliance with
the replacement emission standards promulgated today.
[[Page 59412]]
A. Compliance Dates
The time-line for testing and initial compliance requirements is as
follows:
1. The compliance date is October 14, 2008; \15\
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\15\ See 69 FR at 21313 for rationale. We received no adverse
comments at proposal.
---------------------------------------------------------------------------
2. You must submit a comprehensive performance test plan to the
permitting authority for review and approval 12 months prior to
commencing the test.
3.You must submit an eligibility demonstration for the health-based
compliance alternative to the total chlorine emission standard 12
months before the compliance date if you elect to comply with Sec. 63.1215;
4. You must place in the operating record a Documentation of
Compliance by the compliance date identifying the operating parameter
limits that, using available information, you have determined will
ensure compliance with the emission standards;
5. For boilers and hydrochloric acid production furnaces, you must
commence the initial comprehensive performance test within 6 months
after the compliance date;
6. For incinerators, cement kilns, and lightweight aggregate kilns,
you must commence the initial comprehensive performance test within 12
months after the compliance date;
7. You must complete the initial comprehensive performance test
within 60 days of commencing the test; and
8. You must submit a Notification of Compliance within 90 days of
completing the test documenting compliance with emission standards and
continuous monitoring system requirements.
B. Testing Requirements
All hazardous waste combustors must commence the initial
comprehensive performance test under the time lines discussed above.
The purpose of the comprehensive performance test is to document
compliance with the emission standards of the final rule and establish
operating parameter limits to maintain compliance with those standards.
You must also conduct periodic comprehensive performance testing every
five years.
If your source is subject to a numerical dioxin/furan emission
standard (i.e., incinerators, cement kilns, lightweight aggregate kilns
that comply with the 0.2 ng TEQ/dscm standard, and liquid fuel boilers
equipped with a dry air pollution control device), you must conduct a
dioxin/furan confirmatory performance test no later than 2.5 years
after each comprehensive performance test (i.e., midway between
comprehensive performance tests). If your source is not subject to a
numerical dioxin/furan emission standard (e.g., solid fuel boilers,
lightweight aggregate kilns that comply with the 400 [deg]F temperature
limit at the kiln exit, liquid fuel boilers equipped with wet or no air
pollution control system, and hydrochloric acid production furnaces),
you must conduct a one-time dioxin/furan test to enable the Agency to
evaluate the effectiveness of the carbon monoxide/hydrocarbon standard
and the destruction and removal efficiency standard in controlling
dioxin/furan emissions for those sources. Previous dioxin/furan
emission tests may be used to meet this requirement if the combustor
operated under the conditions required by the rule and if design and
operation of the combustor has not changed since the test in a manner
that could increase dioxin/furan emissions. The Agency will use those
emissions data when reevaluating the MACT standards under CAA section
112(d)(6), when determining whether to develop residual risk standards
for these sources pursuant to section 112(f)(2), and when determining
whether the source's RCRA Permit is protective of human health and the
environment.
You must use the following stack test methods to document
compliance with the emission standards: (1) Method 29 for mercury,
semivolatile metals, and low volatile metals; and (2) Method 26/26A,
Methods 320 or 321, or ASTM D 6735-01 for hydrogen chloride and
chlorine; \16\ (3) either Method 0023A or Method 23 for dioxin/furans;
and (4) either Method 5 or 5i for particulate matter.
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\16\ Note that you may be required to use other test methods to
document emissions of hydrogen chloride and chlorine if you elect to
comply with the alternative, health-based emission limits for total
chlorine under Sec. 63.1215. See Sec. 63.1208(b)(5).
---------------------------------------------------------------------------
C. Initial Compliance Requirements
The initial compliance requirements for solid fuel boilers, liquid
fuel boilers, and hydrochloric acid production furnaces include: \17\
---------------------------------------------------------------------------
\17\ These same requirements currently apply to incinerators,
cement kilns, and lightweight aggregate kilns.
---------------------------------------------------------------------------
1. You must place in the operating record a Documentation of
Compliance by the compliance date identifying the operating parameter
limits that, using available information, you have determined will
ensure compliance with the emission standards;
2. You must develop and comply with a startup, shutdown, and
malfunction plan;
3. You must install an automatic waste feed cutoff system that
links the operating parameter limits to the waste feed cutoff system;
4. You must control combustion system leaks;
5. You must establish and comply with an operator training and
certification program;
6. You must establish and comply with an operation and maintenance plan;
7. If your source is equipped with a baghouse, you must install
either a bag leak detection system or a particulate matter detection
system; \18\ and
---------------------------------------------------------------------------
\18\ A major difference between a bag leak detection system and
a particulate matter detection system is the way the alarm level is
established. The alarm level for a bag leak detection system is
established using concepts in the Agency's bag leak detection system
guidance document while the alarm level for a particulate matter
detection system is established based on the detector response
during the comprehensive performance test. The ash feedrate limit
for incinerators and boilers is waived if you use a particulate
matter detection system but not if you use a bag leak detection
system because the bag leak detection system alarm level may not
provide reasonable assurance of continuous compliance with the
particulate matter emission standard.
---------------------------------------------------------------------------
8. If your source is equipped with an electrostatic precipitator or
ionizing wet scrubber, you must either establish site-specific control
device operating parameter limits which limits are linked to the
automatic waste feed cutoff system, or install a particulate matter
detection system and take corrective measures when the alarm level is
exceeded.
VII. What Are the Continuous Compliance Requirements?
The continuous compliance requirements for solid fuel boilers,
liquid fuel boilers, and hydrochloric acid production furnaces are
identical to those applicable to incinerators, cement kilns, and
lightweight aggregate kilns. See Sec. 63.1209. We note, however, that
today's final rule revises some of these requirements as they apply to
all or specific HWCs (e.g., bag leak detection system requirements;
optional particulate matter detection system requirements; compliance
assurance for thermal emissions-based standards).
You must 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 standards.
You must also establish limits (as applicable) on the feedrate of
metals, chlorine, and ash, key combustor operating parameters, and key
operating
[[Page 59413]]
parameters of the air pollution control device based on operations
during the comprehensive performance test. You must continuously
monitor these parameters with a continuous monitoring system.
VIII. What Are the Notification, Recordkeeping, and Reporting Requirements?
The notification, recordkeeping, and reporting requirements that we
promulgate today for solid fuel boilers, liquid fuel boilers, and
hydrochloric acid production furnaces are identical to those that are
applicable to incinerators, cement kilns, and lightweight aggregate
kilns. See Sec. Sec. 63.1210 and 63.1211. We note, however, that
today's final rule revises some of these requirements as they apply to
all or specific HWCs.
You must submit notifications including the following to the
permitting authority 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. 63.1207(e));
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)); and
4. Various notifications if you request or elect to comply with
alternative requirements at Sec. 63.1210(a)(2).
You must submit the following reports to the permitting authority
in addition to those required by the NESHAP General Provisions, subpart
A of 40 CFR part 63:
1. Startup, shutdown, and malfunction plan, if you elect 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)).
Finally, you must 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
IX. What Is the Health-Based Compliance Alternative for Total Chlorine,
and How Do I Demonstrate Eligibility?
A. Overview
The rule allows you to establish and comply with health-based
compliance alternatives for total chlorine for hazardous waste
combustors other than hydrochloric acid production furnaces in lieu of
the MACT technology-based emission standards established under
Sec. Sec. 63.1216, 63.1217, 63.1219, 63.1220, and 63.1221. See Sec.
63.1215. To identify and comply with the limits, you must:
(1) Identify a total chlorine emission rate for each on-site
hazardous waste combustor. You may select total chlorine emission rates
as you choose to demonstrate eligibility for the health-based limits,
except the total chlorine emission rate limits for incinerators, cement
kilns, and lightweight aggregate kilns cannot result in total chlorine
emission concentrations exceeding the Interim Standards provided by
Sec. Sec. 63.1203, 63.1204, and 63.1205;\19\
---------------------------------------------------------------------------
\19\ Note that the final rule sunsets the Interim Standards on
the compliance date of today's rule but codifies the Interim
Standards for total chlorine under Sec. 63.1215(b)(7).
---------------------------------------------------------------------------
(2) Calculate the HCl-equivalent emission rate for the total
chlorine emission rates you select, considering long-term exposure and
using Reference Concentrations (RfCs) as the health threshold metric.
This emission rate is called the annual average HCl-equivalent emission
rate;
(3) Perform an eligibility demonstration to determine if your
annual average HCl-equivalent emission rate meets the national exposure
standard (i.e., Hazard Index not exceeding 1.0 considering the maximum
annual average ambient concentration of hydrogen chloride and chlorine
at an off-site receptor location which concentrations are attributable
to all on-site hazardous waste combustors) and thus is below the annual
average HCl-equivalent emission rate limit;
(4) Calculate the HCl-equivalent emission rate for the total
chlorine emission rates you select, considering short-term exposure and
using acute Reference Exposure Levels (aRELs) as the health threshold
metric. This emission rate is called the 1-hour average HCl-equivalent
emission rate.
(5) Determine whether your 1-hour HCl-equivalent emission rate may
exceed the national exposure standard (i.e., Hazard Index not exceeding
1.0 considering the maximum 1-hour average ambient concentration of
hydrogen chloride and chlorine at an off-site receptor location which
concentrations are attributable to all on-site hazardous waste
combustors) and thus may exceed the 1-hour average HCl-equivalent
emission rate limit when complying with the annual average HCl-
equivalent emission rate limit, absent an hourly rolling average limit
on the feedrate of total chlorine and chloride.
(6) Submit your eligibility demonstration, including your
determination of whether the 1-hour average HCl-equivalent emission
rate limit may be exceeded absent an hourly rolling average limit on
the feedrate of total chlorine and chloride, for review and approval;
(7) Document during the comprehensive performance test the total
chlorine system removal efficiency for each combustor and use this
system removal efficiency to calculate chlorine feedrate limits. Also,
document that total chlorine emissions during the test do not exceed
the 1-hour average HCl-equivalent emission rate limit during any run of
the test. In addition, establish operating limits on the emission
control device based on operations during the comprehensive performance
test; and
(8) Comply with the requirements for changes in the design,
operation, or maintenance of the facility which could affect the HCl-
equivalent emission rate limits or system removal efficiency for total
chlorine, and changes in the vicinity of your facility over which you
do not have control (e.g., new receptors locating proximate to the facility).
B. HCl-Equivalent Emission Rates
You must express total chlorine emission rates (lb/hr) from each
on-site hazardous waste combustor, including hydrochloric acid
production furnaces \20\, as an annual average HCl-equivalent emission
rate and a 1-hour average HCl-equivalent emission rate. See Sec.
63.1215(b). The annual average HCl-equivalent emission rate equates
chlorine emission rates to hydrogen chloride (HCl) emission rates using
Reference Concentrations (RfCs) as the health risk metric for long-term
exposure. The 1-hour average HCl-equivalent emission rate equates
chlorine emission rates to HCl emission rates using 1-hour Reference
Exposure
[[Page 59414]]
Levels (aRELs) as the health risk metric for acute exposure.
---------------------------------------------------------------------------
\20\ Although hydrochloric acid production furnaces are not
eligible for the health-based total chlorine emission limits
(because control of total chlorine is a surrogate for control of
metal HAP), you must consider total chlorine emissions from
hydrochloric acid production furnaces when demonstrating that total
chlorine emissions from all on-site hazardous waste combustors will
not exceed the Hazard Index limit of 1.0 at an off-site receptor
location.
---------------------------------------------------------------------------
To calculate HCl-equivalent emission rates, you must apportion
total chlorine emissions (ppmv) between chlorine and HCl using the
volumetric ratio of chlorine to hydrogen chloride (Cl2/HCl).
? To calculate the annual average HCl-equivalent emission
rate (lb/hr) and the emission rate limit, you must use the historical
average Cl2/HCl volumetric ratio from all regulatory
compliance tests and the gas flowrate (and other relevant parameters)
from the most recent RCRA compliance test or MACT performance test.
? To calculate the 1-hour average HCl-equivalent emission
rate (lb/hr) and emission rate limit, you must use the highest
Cl2/HCl volumetric ratio from all regulatory compliance
tests and the gas flowrate from the most recent RCRA compliance test or
MACT performance test.
? If you believe that the Cl2/HCl volumetric
ratio for one or more historical compliance tests is not representative
of the current ratio, you may request that the permitting authority
allow you to screen those ratios from the analysis of historical ratios.
? If the permitting authority believes that too few
historical Cl2/HCl ratios are available to establish a
representative average ratio and a representative maximum ratio, the
permitting authority may require you to conduct periodic testing to
establish representative ratios.
? You must include the Cl2/HCl volumetric ratio
demonstrated during each performance test in your data base of
historical Cl2/HCl ratios to update the ratios for
subsequent calculations of the annual average and 1-hour average HCl-
equivalent emission rates (and emission rate limits).
C. Eligibility Demonstration
You must perform an eligibility demonstration to determine whether
the total chlorine emission rates you select for each on-site hazardous
waste combustor meet the national exposure standard (i.e., the Hazard
Index of 1.0 cannot be exceeded at an off-site receptor location
considering maximum annual average ambient concentrations attributable
to all on-site hazardous waste combustors and the RfCs for HCl and
chlorine) using either a look-up table analysis or a site-specific
compliance demonstration.\21\ Eligibility for the health-based total
chlorine standard is determined by comparing the annual average HCl-
equivalent emission rate for the total chlorine emission rate you
select for each combustor to the annual average HCl-equivalent emission
rate limit.
---------------------------------------------------------------------------
\21\ The total chlorine emission rates (lb/hr) for incinerators,
cement kilns, and lightweight aggregate kilns cannot result in total
chlorine emission concentrations (ppmv) exceeding the Interim
Standards provided by Sec. Sec. 63.1203, 63.1204, and 63.1205. The
final rule sunsets the Interim Standards on the compliance date of
today's rule but codifies the Interim Standards for total chlorine
under Sec. 63.1215(b)(7).
---------------------------------------------------------------------------
The annual average HCl-equivalent emission rate limit is the HCl-
equivalent emission rate, determined by equating the toxicity of
chlorine to HCl using RfCs as the health risk metric for long-term
exposure, which ensures that maximum annual average ambient
concentrations of HCl equivalents do not exceed a Hazard Index of 1.0,
rounded to the nearest tenths decimal place (0.1) and considering all
on-site hazardous waste combustors. See Sec. 63.1215(b)(2).
Your facility is eligible for the health-based compliance
alternatives for total chlorine if either: (1) The annual average HCl-
equivalent emission rate for each on-site hazardous waste combustor is
below the HCl-equivalent emission rate limit determined from the
appropriate value for the emission rate limit in the applicable look-up
table and the proration procedure for multiple combustors discussed
below; or (2) the annual average HCl-equivalent emission rate for each
on-site hazardous waste combustor is below the annual average HCl-
equivalent emission rate limit you calculate based on a site-specific
compliance demonstration.
1. Look-Up Table Analysis
Look-up tables for the eligibility demonstration are provided as
Tables 1 and 2 to Sec. 63.1215. Table 1 presents annual average HCl-
equivalent emission rate limits for sources located in flat terrain.
For purposes of this analysis, flat terrain is terrain that rises to a
level not exceeding one half the stack height within a distance of 50
stack heights.
Table 2 presents annual average HCl-equivalent emission rate limits
for sources located in simple elevated terrain. For purposes of this
analysis, simple elevated terrain is terrain that rises to a level
exceeding one half the stack height, but that does not exceed the stack
height within a distance of 50 stack heights.
If your facility is not located in either flat or simple elevated
terrain, you must conduct a site-specific compliance demonstration.
To determine the annual average HCl-equivalent emission rate limit
for a source from the look-up table, you must use the stack height and
stack diameter for your hazardous waste combustors and the distance
between the stack and the property boundary. If any of these values for
stack height, stack diameter, and distance to nearest property boundary
do not match the exact values in the look-up table, you must use the
next lowest table value. If you have more than one hazardous waste
combustor on site, you must adjust the emission rate limits provided by
the tables such that the sum of the ratios for all combustors of the
adjusted emission rate limit to the emission rate limit provided by the
table cannot exceed 1.0. See Sec. 63.1215 (c)(3)(v).
2. Site-Specific Compliance Demonstration
You may use any scientifically-accepted peer-reviewed risk
assessment methodology for your site-specific compliance demonstration
to calculate an annual average HCl-equivalent emission rate limit for
each on-site hazardous waste combustor. 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.
To determine the annual average HCl-equivalent emission rate limit
for each on-site hazardous waste combustor, your site-specific
compliance demonstration must, at a minimum: (1) estimate long-term
inhalation exposures through the estimation of annual or multi-year
average ambient concentrations; (2) estimate the inhalation exposure
for the actual individual most exposed to the facility's emissions from
hazardous waste combustors, considering locations where people reside
and where people congregate for work, school, or recreation; (3) use
site-specific, quality-assured data wherever possible; (4) use health-
protective default assumptions wherever site-specific data are not
available, and: (5) 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.
To establish the annual average HCl-equivalent emission rate limit
for each combustor, you may apportion as you elect among the combustors
the annual average HCl-equivalent emission rate limit for the facility,
which limit ensures that the RfC-based Hazard Index of 1.0 is not
exceeded.
[[Page 59415]]
D. Assurance That the 1-Hour HCl-Equivalent Emission Rate Will Not Be
Exceeded
The long-term, RfC-based Hazard Index will always be higher than
the short-term, aREL-based Hazard Index for a constant HCl-equivalent
emission rate because the health threshold levels for short-term
exposure are orders of magnitude higher than the health threshold
levels for long-term exposure.\22\ Even though maximum 1-hour average
ambient concentrations are substantially higher than maximum annual
average concentrations, the higher short-term ambient concentrations do
not offset the much higher health threshold levels for short-term
exposures. Thus, the long-term, RfC-based Hazard Index will always
govern regarding whether a source can make an eligibility
demonstration. Accordingly, eligibility for the health-based emission
limits is based solely on whether a source can comply with the annual
average HCl-equivalent emission rate limit.
---------------------------------------------------------------------------
\22\ USEPA, ``Technical Support Document for HWC MACT Standards,
Volume III: Selection of MACT Standards,'' September 2005, Section 24.2.
---------------------------------------------------------------------------
Nonetheless, some sources may have highly variably chlorine
feedrates (and corresponding highly variable HCl-equivalent emission
rates) such that they may feed chlorine at very high levels for short
periods of time and still remain in compliance with the chlorine
feedrate limit established to ensure compliance with the annual average
HCl-equivalent emission rate limit.\23\ To ensure that the 1-hour HCl-
equivalent emission rate limit will not be exceeded during these
periods of peak emissions, you must establish a 1-hour average HCl-
equivalent emission rate and 1-hour average HCl-equivalent emission
rate limit for each combustor and consider site-specific factors
including prescribed criteria to determine if the 1-hour average HCl-
equivalent emission rate limit may be exceeded absent an hourly rolling
average limit on chlorine feedrate. If the 1-hour average HCl-
equivalent emission rate limit may be exceeded, you must establish an
hourly rolling average feedrate limit on chlorine.
---------------------------------------------------------------------------
\23\ See discussion below in Section F regarding the requirement
to establish chlorine feedrate limits.
---------------------------------------------------------------------------
You must calculate the 1-hour average HCl-equivalent emission rate
from the total chlorine emission rate you select for each source.
You must establish the 1-hour average HCl-equivalent emission rate
limit for each affected source using either a look-up table analysis or
site-specific analysis. Look-up tables are provided for 1-hour average
HCl-equivalent emission rate limits as Table 3 and Table 4 to this
section. Table 3 provides limits for facilities located in flat
terrain. Table 4 provides limits for facilities located in simple
elevated terrain. You must use the Tables to establish emission rate
limits in the same manner as you use Tables 1 and 2 to establish annual
average HCl-equivalent emission rate limits.
If you conduct a site-specific analysis to establish a 1-hour
average HCl-equivalent emission rate limit, you must follow the risk
assessment procedures you used to establish an annual average HCl-
equivalent emission rate limit. The 1-hour HCl-equivalent emission rate
limit, however, is the emission rate than ensures that the Hazard Index
associated with maximum 1-hour average exposures is not greater than 1.0.
You must consider criteria including the following to determine if
a source may exceed the 1-hour HCl-equivalent emission rate limit
absent an hourly rolling average chlorine feedrate limit: (1) The ratio
of the 1-hour average HCl-equivalent emission rate based on the total
chlorine emission rate you select for each hazardous waste combustor to
the 1-hour average HCl-equivalent emission rate limit for the
combustor; and (2) the potential for the source to vary total chlorine
and chloride feedrates substantially over the averaging period for the
feedrate limit you establish to ensure compliance with the annual
average HCl-equivalent emission rate limit.
If you determine that a source may exceed the 1-hour average HCl-
equivalent emission rate limit, you must establish an hourly rolling
average chlorine feedrate limit as discussed below in Section G.
You must include the following information in your eligibility
demonstration to document your determination whether an hourly rolling
average feedrate limit is needed to maintain compliance with the 1-hour
HCl-equivalent emission rate limit: (1) Determination of the Cl2/HCl
volumetric ratio established for 1-hour average HCl-equivalent emission
rate determinations as provided by Sec. 63.1215(b)(6)(ii); (2)
determination of the 1-hour average HCl-equivalent emission rate
calculated from the total chlorine emission rate you select for the
combustor; (3) determination of the 1-hour average HCl-equivalent
emission rate limit; (4) determination of the ratio of the 1-hour
average HCl-equivalent emission rate to the 1-hour HCl-equivalent
emission rate limit for the combustor; and (5) determination of the
potential for the source to vary chlorine feedrates substantially over
the averaging period for the long-term feedrate limit (i.e., 12-hours,
or up to annually) established to maintain compliance with the annual
average HCl-equivalent emission rate limit.
E. Review and Approval of Eligibility Demonstrations
The permitting authority will review and approve your eligibility
demonstration. Your eligibility demonstration must contain, at a
minimum, the information listed in Sec. 63.1215(d)(1).
1. Review and Approval for Existing Sources
If you operate an existing source, 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 also 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, electronic
mail address REAG@epa.gov.
Your permitting authority should 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 or to comply with the MACT total chlorine standards. If
your eligibility demonstration is disapproved, the permitting authority
may extend the compliance date of the total chlorine standard to allow
you to make changes to the design or operation of the combustor or
related systems as quickly as practicable to enable you to achieve
compliance with the MACT standard for total chlorine.
If your permitting authority has not approved your eligibility
demonstration by the compliance date, and has not issued a notice of
intent to disapprove your demonstration, you may nonetheless begin
complying, on the compliance date, with the annual average HCl-
equivalent emission rate limits you present in your eligibility
demonstration.
If your permitting authority issues a notice of intent to
disapprove your eligibility demonstration after the
[[Page 59416]]
compliance date, the authority will identify the basis for that notice
and specify how much time you will have to submit additional
information or to comply with the MACT total chlorine standards. The
permitting authority may extend the compliance date of the total
chlorine standard to allow you to make changes to the design or
operation of the combustor or related systems as quickly as practicable
to enable you to achieve compliance with the MACT standard for total
chlorine.
2. Review and Approval for New and Reconstructed Sources
The procedures for review and approval of eligibility
demonstrations applicable to existing sources discussed above also
apply to new or reconstructed sources, except that the date you must
submit the eligibility demonstration is as discussed below.
If you operate a new or reconstructed source that starts up by
April 12, 2007, 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
April 12, 2007, you must either: (1) Submit an eligibility
demonstration for review and approval by April 12, 2006 and comply with
the HCl-equivalent emission rate limits and operating requirements you
establish in the eligibility demonstration; or (2) comply with the
final total chlorine emission standards under Sec. Sec. 63.1216,
63.1217, 63.1219, 63.1220, and 63.1221, by October 12, 2005, or upon
startup, whichever is later, except for a standard that is more
stringent than the standard proposed on April 20, 2004 for your source.
If a final standard is more stringent than the proposed standard, you
may comply with the proposed standard until October 14, 2008, after
which you must comply with the final standard.
If you operate a new or reconstructed source that starts up on or
after April 12, 2007, 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 on or
after April 12, 2007, you must comply with either of the following. You
may submit an eligibility demonstration for review and approval 12
months prior to startup. Alternatively, you may comply with the final
total chlorine emission standards under Sec. Sec. 63.1216, 63.1217,
63.1219, 63.1220, and 63.1221 upon startup. If the final standard is
more stringent than the standard proposed for your source on April 20,
2004, however, and if you start operations before October 14, 2008, you
may comply with the proposed standard until October 14, 2008, after
which you must comply with the final standard.
F. Testing Requirements
You must comply with the requirements for comprehensive performance
testing under Sec. 63.1207.
1. Test Methods for Stack Gas Containing Alkaline Particulate
If you operate a cement kiln or a combustor equipped with a dry
acid gas scrubber, you must 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.
2. Test Methods for Stack Gas Containing High Levels of Bromine or Sulfur
If you operate an incinerator, boiler, or lightweight aggregate
kiln and your feedstreams contain bromine or sulfur during the
comprehensive performance test at the levels indicated below, 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 chlorine and hydrogen chloride combined. You must determine
your chlorine emissions to be the higher of: (1) The value measured by
Method 26/26A, or an equivalent method; or (2) the value calculated by
the difference between the combined hydrogen chloride and chlorine
levels measured by Method 26/26a, or an equivalent method, and the
hydrogen chloride measurement from EPA Method 320/321 or ASTM D 6735-
01, or an equivalent method.
These procedures apply if you feed during the comprehensive
performance test bromine at a bromine/chlorine ratio in feedstreams
greater than 5 percent by mass, or sulfur at a sulfur/chlorine ratio in
feedstreams greater than 50 percent by mass.\24\
---------------------------------------------------------------------------
\24\ USEPA, ``Technical Support Document for HWC MACT Standards,
Volume IV: Compliance with the HWC MACT Standards,'' September 2005,
Chapter 15.1.2.
---------------------------------------------------------------------------
Finally, you should precondition the M26/26A filter for one hour
prior to beginning the performance test to minimize the potential for a
low bias caused by adsorption/absorption of hydrogen chloride on the
filter.
G. Monitoring Requirements
You must establish and comply with 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 described below.
1. Feedrate Limit to Ensure Compliance with the Annual Average HCl-
Equivalent Emission Rate Limit
For sources subject to the feedrate limit for total chlorine and
chloride under Sec. 63.1209(n)(4) to ensure compliance with the
semivolatile metals standard, the feedrate limit (and averaging period)
for total chlorine and chloride to ensure compliance with the annual
average HCl-equivalent emission rate limit is the same as required by
that paragraph. Thus, the chlorine feedrate limit is the average of the
run averages during the comprehensive performance test, and is
established as a 12-hour rolling average.
That chlorine feedrate limit cannot exceed the numerical value
(i.e., not considering the averaging period) of the feedrate limit that
ensures compliance with the annual average HCl-equivalent emission rate
limit, however. Therefore, the numerical value of the total chlorine
and chloride feedrate limit must not exceed the value you calculate as
the annual average HCl-equivalent emission rate limit (lb/hr) divided
by [1 - system removal efficiency]. You must calculate a total chlorine
system removal efficiency for each test run of the comprehensive
performance test as [1 - total chlorine emission rate (g/s)/chlorine
feedrate (g/s)], and calculate the average system removal efficiency of
the test run averages. If your source does not control total chlorine,
you must assume zero system removal efficiency. If emissions during the
comprehensive performance test exceed the annual average HCl-equivalent
emission rate limit, eligibility for the health-based emission limits
is not affected. This is because the emission rate limit is an annual
average limit. Compliance is based on a 12-hour rolling average
chlorine feedrate limit (rather than an (up to) an annual averaging
period) for sources subject to the 12-hour rolling average feedrate
limit for total chlorine and chloride under Sec. 63.1209(n)(4) to
ensure compliance with the semivolatile metals standard given that the
more stringent feedrate limit (i.e., the feedrate limit with the
shorter averaging period) would apply.
For sources exempt from the feedrate limit for total chlorine and
chloride under Sec. 63.1209(n)(4) because they comply with Sec.
63.1207(m)(2) (which allows compliance with the semivolatile metals
emission standard absent emissions testing by assuming all metals fed
are emitted), the feedrate limit for total chlorine and chloride to ensure
[[Page 59417]]
compliance with the annual average HCl-equivalent emission rate must be
established as follows:
? You must establish an average period for the feedrate
limit that does not exceed an annual rolling average;
? You must calculate a total chlorine system removal
efficiency for each test run of the comprehensive performance test as
[1 - total chlorine emission rate (g/s)/chlorine feedrate (g/s)], and
calculate the average system removal efficiency of the test run
averages. If your source is not equipped with a control system that
consistently and reproducibly controls total emissions (e.g., wet or
dry scrubber), you must assume zero system removal efficiency. If
emissions during the comprehensive performance test exceed the annual
average HCl-equivalent emission rate limit, eligibility for emission
limits under this section is not affected. The emission rate limit is
an annual average limit and compliance is based on an annual average
feedrate limit on total chlorine and chloride (or a shorter averaging
period if you so elect under paragraph (g)(2)(ii)(A) of this section);
and
? You must calculate the feedrate limit for total chlorine
and chloride as the annual average HCl-equivalent emission rate limit
(lb/hr) divided by [1 - system removal efficiency]
and comply with the
feedrate limit on the averaging period you establish.
2. Feedrate Limit To Ensure Compliance With the 1-Hour Average HCl-
Equivalent Emission Rate Limit
You must establish an hourly rolling average feedrate limit on
total chlorine and chloride to ensure compliance with the 1-hour
average HCl-equivalent emission rate limit unless you determine that
the hourly rolling average feedrate limit is waived as discussed under
Section D above. If required, you must calculate the hourly rolling
average feedrate limit for total chlorine and chloride as the 1-hour
average HCl-equivalent emission rate limit (lb/hr) divided by [1 -
system removal efficiency]
using the system removal efficiency
demonstrated during the comprehensive performance test.
H. Relationship Among Emission Rates, Emission Rate Limits, and
Feedrate Limits
We summarize here the relationship among: (1) the total chlorine
emission rate you select in your eligibility demonstration; (2) the
annual average and 1-hour average HCl-equivalent emission rates you
present in your eligibility demonstration; (3) the annual average and
1-hour average emission rate limits you present in your eligibility
demonstration; (4) performance test emission rates for total chlorine
and HCl-equivalent emissions; and (5) long-term and hourly rolling
average chlorine feedrate limits.
1. Total Chlorine Emission Rate, Annual Average HCl-Equivalent Emission
Rate, and Annual Average HCl-Equivalent Emission Rate Limit
For the eligibility demonstration, you must select a total chlorine
emission concentration (ppmv) for each combustor, determine the
Cl2/HCl volumetric ratio, calculate the annual average HCl-
equivalent emission rate (lb/hr), and document that the emission rate
does not exceed the annual average HCl-equivalent emission rate limit.
You select a total chlorine (i.e., HCl and chlorine combined)
emission concentration (ppmv) for each hazardous waste combustor
expressed as chloride (Cl(-)) equivalent. For incinerators,
cement kilns, and lightweight aggregate kilns, this emission
concentration cannot exceed the Interim Standards for total chlorine.
You then determine the average Cl2/HCl volumetric ratio
considering all historical regulatory emissions tests and apportion
total chlorine emissions between Cl2 and HCl accordingly.
You use these apportioned volumetric emissions to calculate the
Cl2 and HCl emission rates (lb/hr) using the average gas
flowrate (and other relevant parameters) for the most recent RCRA
compliance test or MACT performance test for total chlorine. Finally,
you use these Cl2 and HCl emission rates to calculate an
annual average HCl-equivalent emission rate, which cannot exceed the
annual average HCl-equivalent emission rate limit that you establish as
discussed below.
To establish the annual average HCl-equivalent emission rate limit,
you may either use Tables 1 or 2 in Sec. 63.1215 to look-up the limit,
or conduct a site-specific risk analysis. Under the site-specific risk
analysis option, the annual average HCl-equivalent emission rate limit
would be the highest emission rate that the risk assessment estimates
would result in a Hazard Index not exceeding 1.0 for the actual
individual most exposed to the facility's emissions considering off-
site locations where people reside and where people congregate for
work, school, or recreation.
If you have more than one on-site hazardous waste combustor, and if
you use the look-up tables to establish the annual average HCl-
equivalent emission rate limits, the sum of the ratios for all
combustors of the annual average HCl-equivalent emission rate to the
annual average HCl-equivalent emission rate limit cannot not exceed
1.0. This will ensure that the RfC-based Hazard Index of 1.0 is not
exceeded, a principle criterion of the eligibility demonstration.
If you use site-specific risk analysis to demonstrate that a Hazard
Index of 1.0 is not exceeded, you would generally identify for each
combustor the maximum annual average HCl-equivalent emission rate that
the risk assessment estimates would result in an RfC-based Hazard Index
of 1.0 at any off-site receptor location (i.e., considering locations
where people reside and where people congregate for work, school, or
recreation.\25\ This emission rate would be the annual average HCl-
equivalent emission rate limit for each combustor.
---------------------------------------------------------------------------
\25\ Note again, however, that the total chlorine emission
concentration (ppmv) is capped by the Interim Standards for
incinerators, cement kilns, and lightweight aggregate kilns.
---------------------------------------------------------------------------
2. 1-Hour Average HCl-Equivalent Emission Rate and Emission Rate Limit
As discussed in Section D above, you must determine in your
eligibility demonstration whether the 1-hour HCl-equivalent emission
rate limit may be exceeded absent an hourly rolling average chlorine
feedrate limit. To make this determination, you must establish a 1-hour
average HCl-equivalent emission rate and a 1-hour average HCl-
equivalent emission rate limit.
You calculate the 1-hour average HCl-equivalent emission rate from
the total chlorine emission rate, established as discussed above, using
the equation in Sec. 63.1215(b)(3).
You establish the 1-hour average HCl-equivalent emission rate limit
by either using Tables 3 or 4 in Sec. 63.1215 to look-up the limit, or
conducting a site-specific risk analysis. Under the site-specific risk
analysis option, the 1-hour average HCl-equivalent emission rate limit
would be the highest emission rate that the risk assessment estimates
would result in an aREL-based Hazard Index not exceeding 1.0 at any
off-site receptor location (i.e., considering locations where people
reside and where people congregate for work, school, or recreation).
3. Performance Test Emissions
During the comprehensive performance test, you must demonstrate a
system removal efficiency for total chlorine as [1 - TCl emitted (lb/
hr)/chlorine fed (lb/hr)]. During the test, however, the total chlorine
emission rate you select for each combustor and the annual average HCl-
equivalent
[[Page 59418]]
emission rate limit can exceed the levels you present in the
eligibility demonstration. This is because those emission rates are
annual average rates and need not be complied with over the duration of
three runs of the performance test, which may be nominally only 3 hours.
The 1-hour average HCl-equivalent emission rate limit cannot be
exceeded during any run of the comprehensive performance test, however.
This limit is based on an aREL Hazard Index of 1.0; an exceedance of
the limit over a test run with a nominal 1-hour duration would result
in a Hazard Index of greater than 1.0.
4. Chlorine Feedrate Limits
To maintain compliance with the annual average HCl-equivalent
emission rate limit, you must establish a long-term average chlorine
feedrate limit. In addition, if you determine under Sec. 63.1205(d)(3)
that the 1-hour average HCl-equivalent emission rate may be exceeded
(i.e., because your chlorine feedrate may vary substantially over the
averaging period for the long-term chlorine feedrate limit), you must
establish an hourly rolling average chlorine feedrate limit.
Long-Term Chlorine Feedrate Limit. The chlorine feedrate limit to
maintain compliance with the annual average HCl-equivalent emission
rate is either: (1) The chlorine feedrate during the comprehensive
performance test if you demonstrate compliance with the semivolatile
metals emission standard during the test (see Sec. 63.1209(o)); or (2)
if you comply with the semivolatile metals emission standard under
Sec. 63.1207(m)(2) by assuming all metals in the feed to the combustor
are emitted, the HCl-equivalent emission rate limit divided by [1 -
system removal efficiency]
where you demonstrate the system removal
efficiency during the comprehensive performance test.
If you establish the chlorine feedrate limit based on the feedrate
during the performance test to demonstrate compliance with the
semivolatile metals emission standard, the averaging period for the
feedrate limit is a 12-hour rolling average. If you establish the
chlorine feedrate limit based on the system removal efficiency during
the performance test, the averaging period is up to an annual rolling
average. See discussion in Part Four, Section VII.B of this preamble.
If you comply with the semivolatile metals emission standard under
Sec. 63.1207(m)(2), however, the long-term chlorine feedrate limit is
based on the system removal efficiency during the comprehensive
performance test rather than the feedrate during the performance test.
This is because the averaging period for this chlorine feedrate limit
(that ensures compliance with the annual average HCl-equivalent
emission rate limit) is up to an annual rolling average. See Sec.
63.1215(g)(2). Thus, the chlorine feedrate, and total chlorine
emissions, can be higher than the limit during the relatively short
duration of the comprehensive performance tests.
Hourly Rolling Average Chlorine Feedrate Limit. If you determine
under Sec. 63.1205(d)(3) that the 1-hour average HCl-equivalent
emission rate limit may be exceeded, you must establish an hourly
rolling average chlorine feedrate limit. That feedrate limit is
established as the 1-hour HCl-equivalent emission rate limit divided by
[1 - system removal efficiency]. The hourly rolling average chlorine
feedrate limit is not established based on feedrates during the
performance test because performance test feedrates may be
substantially lower than the feedrate needed to ensure compliance with
the 1-hour average HCl-equivalent emission rate. Note, however, that
the hourly rolling average feedrate limit cannot be exceeded during any
run of the comprehensive performance test. This chlorine feedrate limit
is based on the 1-hour average HCl-equivalent emission rate limit,
which is based on an aREL Hazard Index of 1.0. Thus, an exceedance of
the hourly rolling average feedrate limit (and the 1-hour lHCl-
equivalent emission rate limit) over a test run with a nominal 1-hour
duration would result in a Hazard Index of greater than 1.0.
I. Changes
Your requirements will change in response to changes that affect
the HCl-equivalent emission rate or HCl-equivalent emission rate limit
for a source.
1. Changes Over Which You Have Control
Changes That Affect HCl-Equivalent Emission Rate Limits. If you
plan to change the design, operation, or maintenance of the facility in
a manner that would decrease the annual average or 1-hour average HCl-
equivalent emission rate limit (e.g., reduce the distance to the
property line; reduce stack gas temperature; reduce stack height),
prior to the change you must submit to the permitting authority a
revised eligibility demonstration documenting the lower emission rate
limits and calculations of reduced total chlorine and chloride feedrate
limits.
If you plan to change the design, operation, or maintenance of the
facility in a manner than would increase the annual average or 1-hour
average HCl-equivalent emission rate limit, and you elect to increase
your total chlorine and chloride feedrate limits, prior to the change
you must submit to the permitting authority a revised eligibility
demonstration documenting the increased emission rate limits and
calculations of the increased feedrate limits prior to the change.
Changes That Affect System Removal Efficiency. If you plan to
change the design, operation, or maintenance of the combustor in a
manner than could decrease the system removal efficiency, you are
subject to the requirements of Sec. 63.1206(b)(5) for conducting a
performance test to reestablish the combustor's system removal
efficiency. You also must submit a revised eligibility demonstration
documenting the lower system removal efficiency and the reduced
feedrate limits on total chlorine and chloride.
If you plan to change the design, operation, or maintenance of the
combustor in a manner than could increase the system removal
efficiency, and you elect to document the increased system removal
efficiency to establish higher feedrate limits on total chlorine and
chloride, you are subject to the requirements of Sec. 63.1206(b)(5)
for conducting a performance test to reestablish the combustor's system
removal efficiency. You must also submit a revised eligibility
demonstration documenting the higher system removal efficiency and the
increased feedrate limits on total chlorine and chloride.
2. Changes Over Which You Do Not Have Control
If you use site-specific risk assessment in lieu of the look-up
tables to establish the HCl-equivalent emission rate limit, you must
review the documentation you use in your eligibility demonstration
every five years from the date 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 annual average HCl-equivalent emission rate limit, or a
revised eligibility demonstration. Examples of changes beyond your
control that may decrease the annual average HCl-equivalent emission
rate limit (or 1-hour average HCl-equivalent emission rate limit) are
construction of residences at a location exposed to higher ambient
[[Page 59419]]
concentrations than evaluated during your previous risk analysis, or a
reduction in the RfCs or aRELs.
If, in the interim between the dates of your comprehensive
performance tests, you have reason to know of changes that would
decrease the annual average HCl-equivalent emission rate limit, you
must submit a revised eligibility demonstration as soon as practicable
but not more frequently than annually.
If you determine that you cannot demonstrate compliance with a
lower annual average HCl-equivalent emission rate limit (dictated by a
change over which you do not have control) during the comprehensive
performance test because you need additional time to complete changes
to the design or operation of the source or related systems, you may
request that the permitting authority grant you additional time to make
those changes as quickly as practicable.
X. Overview on Floor Methodologies
The most contentious issue in the rulemaking involved methodologies
for determining MACT floors, namely, which sources are best performing,
and what is their level of performance. Superficially, these questions
have a ready answer: the best performers are the lowest emitters as
measured by compliance tests, and those tests fix their level of
performance. But compliance tests are snapshots which do not fully
capture sources' total operating variability. Since the standards must
be met at all times, picking lowest compliance test data to set the
standard results in standards best performing sources themselves would
be unable to meet at all times.
To avoid this impermissible result, EPA selected approaches that
reasonably estimate best performing sources' total variability. Certain
types of variability can be quantified statistically, and EPA did so
here (using standard statistical approaches) in all of the floor
methodologies used in the rule. There are other components of
variability, however, which cannot be fully quantified, but nonetheless
must be accounted for in reasonably estimating best performing sources'
performance over time. EPA selected ranking methodologies which best
account for this total variability.
Where control of the feed of HAP is feasible and technically
assessable (the case for HAP metals and for total chlorine), EPA used a
methodology that ranked sources by their ability to best control both
HAP feed and HAP emissions. This methodology thus assesses the
efficiency of control of both the HAP inputs to a hazardous waste
combustion unit, and the efficiency of control of the unit's outputs.
This methodology reasonably selects the best performing (and for new
sources, best controlled) sources, and reasonably assesses their level
of performance. When HAP feed control is not feasible, notably where
HAP is contributed by raw material and fossil fuel inputs, EPA
determined best performers and their level of performance using a
methodology that selects the lowest emitters using the best air
pollution control technology. This methodology reasonably estimates the
best performing sources' level of performance, and better accounts for
total variability in emissions levels of the best performing sources.
EPA carefully examined approaches selecting lowest emitters as best
performers. Examination of other test conditions from the same best
performing sources shows, however, that this approach results in
standards not achievable even by the best performers. Indeed, in order
to meet such standards, even ``best performing'' sources (lowest
emitting in individual tests) would have to add additional air
pollution control technology. EPA views this result as an end run
around the section 112(d)(2) beyond-the-floor process, because floor
standards would force industry-wide technological changes without
consideration of the factors (cost and energy in particular) which
Congress mandated for consideration when establishing beyond-the-floor
standards.
Part Three: What Are the Major Changes Since Proposal?
I. Database
A. Hazardous Burning Incinerators
Five incinerators have been removed from the database because they
have initiated or completed RCRA closure.\26\ Two incinerators have
been added to the list of sources used to calculate the floor
levels.\27\ Emissions data from source 3015 has been excluded for
purposes of calculating the particulate matter floor because the source
was processing an atypical waste stream from a particulate matter
compliance perspective. See part four, section I.F. We have excluded
the most recent mercury and dioxin/furan emissions data from source
327, and have instead used data from an older test condition to
represent this source's emissions because the source encountered
problems with its carbon injection system during the most recent test.
See part four, section I.F. Emissions data from source 3006 has been
excluded for purposes of calculating the semivolatile metal standard
because this source did not measure cadmium emissions during its
emissions test. See part four, section I.F. We have added mercury
emissions data from source 901 (DSSI) to the incinerator mercury
database because this source (which is otherwise subject to standards
for liquid fuel boilers) is burning a waste which is unlike that burned
by any other liquid fuel boiler with respect to mercury concentration
and waste provenance, but typical of waste burned by incinerators with
respect to those factors. See part four, section VI.D.1. This change
correspondingly affects the liquid fuel boiler standard by removing
that data from the liquid fuel boiler database.
---------------------------------------------------------------------------
\26\ See ``Final Technical Support Document for HWC MACT
Standards, Volume II: HWC Database'' for a list of the sources that
have initiated or completed RCRA closure.
\27\ We noticed the data from these sources but did not include
them in the MACT standard calculations at proposal. Note that
inclusion of these sources did not affect any of the calculated MACT
standards. See ``Final Technical Support Document for HWC MACT
Standards, Volume II: HWC Database'' for more discussion.
---------------------------------------------------------------------------
B. Hazardous Waste Cement Kilns
1. Use of Emissions Data From Ash Grove Cement Company
The emissions data from Ash Grove Cement Company, which operates a
recently constructed preheater/precalciner kiln located in Chanute,
Kansas, are considered when calculating MACT floors for new hazardous
waste burning cement kilns. In the proposal, we did not consider their
emissions data in the floor analyses for existing sources because Ash
Grove Cement used the data to demonstrate compliance with the new
source interim standards, and did not address the data for purposes of
new source standards. See 69 FR at 21217 n. 35. Consistent with our
position on use of post-1999 emissions data, we are including Ash Grove
Cement's emissions data in the floor analyses for new sources. See also
Part Four, Section I.B of the preamble.
2. Removal of Holcim's Emissions Data From EPA's HWC Data Base
Following cessation of hazardous waste operations in 2003, we are
removing all emissions data from both wet process cement kilns at
Holcim's Holly Hill, South Carolina, plant from our hazardous waste
combustor data base. This is consistent with our approach in both this
rule and the 1999 rule to base the standards only on performance of
sources that actually are operating (i.e., burning hazardous waste).
See also Part Four, Section I.A and 64 FR at 52844.
[[Page 59420]]
3. Use of Mercury Data
As discussed below, we are using a commenter-submitted dataset as
the basis of the mercury standards for existing and new cement kilns.
This comprehensive dataset documents the day-to-day levels of mercury
in hazardous waste fired to all cement kilns for a three year period
covering 1999 to 2001. We have determined that the commenter-submitted
data are more representative than data used at proposal. See Part Four,
Section I.D of the preamble for our rationale.
C. Hazardous Waste Lightweight Aggregate Kilns
We are incorporating mercury data submitted by a commenter into the
MACT floor analysis for existing and new lightweight aggregate kilns.
These data document the day-to-day levels of mercury in hazardous waste
fired to lightweight aggregate kilns located at Solite Corporation's
Arvonia plant between October 2003 and June 2004. We have determined
that the commenter-submitted data are more representative than the data
used at proposal. See Part Four, Section I.E of the preamble for our
rationale.
D. Liquid Fuel Boilers
In the proposed rule, we classified liquid fuel boilers as one
category. The final rule classifies them into two for purposes of the
mercury, semivolatile metals, chromium, and total chlorine standards:
one for liquid fuel boilers burning lower heating value hazardous waste
(hazardous waste with a heating value less than 10,000 Btu/lb), and
another for liquid fuel boilers burning higher heating value hazardous
waste (hazardous waste with a heating value of 10,000 Btu/lb or greater).
We also made other, minor changes to the data base because some
sources have initiated closure, were misclassified as other sources in
the proposed rule, or were inadvertently not considered in the floor
calculations although the sources' test reports were in the docket at
proposal.
E. HCl Production Furnaces
Six of the 17 hydrochloric acid production furnaces have ceased
burning hazardous waste since proposal. Consequently, we do not use
emissions data from these sources to establish the final standards. All
six of these sources were equipped with waste heat recovery boilers and
had relatively high dioxin/furan emissions. In addition, we
reclassified source #2020 as a boiler based on comments
received at proposal.
F. Total Chlorine Emissions Data Below 20 ppmv
We corrected all the total chlorine measurements in the data base
that were below 20 ppmv to account for potential systemic negative
biases in the Method 0050 data in response to comments on the proposed
rule. See the discussion in Part Four, Section I.C.1 below.
To account for the bias, we corrected all total chlorine emissions
data that were below 20 ppmv to 20 ppmv. We accounted for within-test
condition emissions variability for the corrected data by imputing a
standard deviation that is based on a regression analysis of run-to-run
standard deviation versus emission concentration for all data above 20
ppmv. This approach of using a regression analysis to impute a standard
deviation is similar to the approach we used to account for total
variability (i.e., test-to-test and within test variability) of PM
emissions for sources that use fabric filters.
II. Emission Limits
A. Incinerators
The changes in the incinerator standards for existing sources since
proposal are:
------------------------------------------------------------------------
Standard Proposed limit Final limit
------------------------------------------------------------------------
Dioxin/Furans (ng TEQ/dscm). Sources with dry air For all sources,
pollution control 0.20 or 0.40 and
systems or waste temperature control
heat boilers: 0.28; < 400 [deg]F at the
For others: 0.2 or air pollution
0.4 and temperature control device
control at inlet of inlet.
air pollution
control device <
400 [deg]F.
Particulate Matter (gr/dscf) 0.015............... 0.013.
Semivolatile Metals ([mu]g/ 59.................. 230.
dscm).
Low Volatile Metals ([mu]g/ 84.................. 92.
dscm).
Total Chlorine (ppmv)....... 1.5................. 32.
Alternative to the 59.................. 230.
particulate matter
standard: Combined
emissions of lead, cadmium
and selenium ([mu]g/dscm).
Alternative to the 84.................. 92.
particulate matter
standard: Combined
emissions of arsenic,
berrylium, chrome,
antimony, cobalt,
manganese, and nickel
([mu]g/dscm).
------------------------------------------------------------------------
The changes in the incinerator standards for new sources since
proposal are:
------------------------------------------------------------------------
Proposed Final
Standard limit limit
------------------------------------------------------------------------
Particulate Matter (gr/dscf).................... 0.0007 0.0015
Mercury ([mu]g/dscm)............................ 8.0 8.1
Semivolatile Metals ([mu]g/dscm)................ 6.5 10
Low Volatile Metals ([mu]g/dscm)................ 8.9 23
Total Chlorine (ppmv)........................... 0.18 21
Alternative to the particulate matter standard: 6.5 10
Combined emissions of lead, cadmium and
selenium ([mu]g/dscm)..........................
Alternative to the particulate matter standard: 8.9 23
Combined emissions of arsenic, berrylium,
chrome, antimony, cobalt, manganese, and nickel
([mu]g/dscm)...................................
------------------------------------------------------------------------
[[Page 59421]]
Hazardous Waste Burning Cement Kilns
The changes in the standards for existing cement kiln since
proposal are:
------------------------------------------------------------------------
Standard Proposed limit Final limit
------------------------------------------------------------------------
Mercury ([mu]g/dscm)........ 64 1................ Both 3.0 ppmw 2 and
either 120 [mu]g/
dscm (stack
emissions) or 120
[mu]g/dscm
(expressed as a
hazardous waste
MTEC) 3.
Particulate matter.......... 0.028 gr/dscf....... 0.028 gr/dscf and
20% opacity 4.
Semivolatile metals......... 4.0E-04 lb/MMBtu 5.. 7.6E-04 lb/MMBtu 5
and 330 [mu]g/dscm.
Low volatile metals......... 1.4E-05 lb/MMBtu 5.. 2.1E-05 lb/MMBtu 5
and 56 [mu]g/dscm.
Total chlorine (ppmv) 6..... 110................. 120.
------------------------------------------------------------------------
1 The proposed mercury standard was an annual limit.
2 Feed concentration of mercury in hazardous waste as-fired.
3 HW MTEC means maximum theoretical emissions concentration of the
hazardous waste and MTEC is defined at Sec. 63.1201(a).
4 The opacity standard does not apply to a source equipped with a bag
leak detection system under Sec. 63.1206(c)(8) or a particulate
matter detection system under Sec. 63.1206(c)(9).
5 Standard is expressed as mass of pollutant stack emissions
attributable to the hazardous waste per million British thermal unit
heat input of the hazardous waste.
6 Combined standard, reported as a chloride (Cl(-)) equivalent.
The changes in the standards for new cement kilns since proposal are:
------------------------------------------------------------------------
Standard Proposed limit Final limit
------------------------------------------------------------------------
Mercury ([mu]g/dscm)........ 35 \1\.............. Both 1.9 ppmw 2 and
either 120 [mu]g/
dscm (stack
emissions) or 120
[mu]g/dscm
(expressed as a
hazardous waste
MTEC) 3.
Particulate matter.......... 0.0058 gr/dscf...... 0.0023 gr/dscf and
20% opacity 4.
Semivolatile metals......... 6.2E-05 lb/MMBtu 5.. 6.2E-05 lb/MMBtu 5
and 180 [mu]g/dscm.
Low volatile metals......... 1.4E-05 lb/MMBtu 5.. 1.5E-05 lb/MMBtu 5
and 54 [mu]g/dscm.
Total chlorine (ppmv) 6..... 78.................. 86.
------------------------------------------------------------------------
1 The proposed mercury standard was an annual limit.
2 Feed concentration of mercury in hazardous waste as-fired.
3 HW MTEC means maximum theoretical emissions concentration of the
hazardous waste and MTEC is defined at Sec. 63.1201(a).
4 The opacity standard does not apply to a source equipped with a bag
leak detection system under Sec. 63.1206(c)(8) or a particulate
matter detection system under Sec. 63.1206(c)(9).
5 Standard is expressed as mass of pollutant stack emissions
attributable to the hazardous waste per million British thermal unit
heat input of the hazardous waste.
6 Combined standard, reported as a chloride (Cl(-)) equivalent.
C. Hazardous Waste Burning Lightweight Aggregate Kilns
The changes in the standards for existing lightweight aggregate
kilns since proposal are:
------------------------------------------------------------------------
Standard Proposed limit Final limit
------------------------------------------------------------------------
Dioxins and furans (ng TEQ/ 0.40................ 0.20 or rapid quench
dscm). of the flue gas at
the exit of the
kiln to less than
400 [deg]F.
Mercury ([mu]g/dscm)........ 67 1................ 120 [mu]g/dscm
(stack emissions)
or 120 [mu]g/dscm
(expressed as a
hazardous waste
MTEC) 2.
Semivolatile metals......... 3.1E-04 lb/MMBtu 3 3.0E-04 lb/MMBtu 3
and 250 [mu]g/dscm. and 250 [mu]g/dscm.
------------------------------------------------------------------------
1 The proposed mercury standard was an annual limit.
2 HW MTEC means maximum theoretical emissions concentration of the
hazardous waste and MTEC is defined at Sec. 63.1201(a).
3 Standard is expressed as mass of pollutant stack emissions
attributable to the hazardous waste per million British thermal unit
heat input of the hazardous waste.
The changes in the standards for new lightweight aggregate kilns
since proposal are:
------------------------------------------------------------------------
Standard Proposed limit Final limit
------------------------------------------------------------------------
Dioxins and furans (ng TEQ/ 0.40................ 0.20 or rapid quench
dscm). of the flue gas at
the exit of the
kiln to less than
400 [deg]F.
[[Page 59422]]
Particulate matter.......... 0.0099 gr/dscf...... 0.0098 gr/dscf.
Mercury ([mu]g/dscm)........ 67 1................ 120 [mu]g/dscm
(stack emissions)
or 120 [mu]g/dscm
(expressed as a
hazardous waste
MTEC) 2.
Semivolatile metals......... 2.4E-05 lb/MMBtu 3 3.7E-05 lb/MMBtu 3
and 43 [mu]g/dscm. and 43 [mu]g/dscm.
------------------------------------------------------------------------
1 The proposed mercury standard was an annual limit.
2 HW MTEC means maximum theoretical emissions concentration of the
hazardous waste and MTEC is defined at Sec. 63.1201(a).
3 Standard is expressed as mass of pollutant stack emissions
attributable to the hazardous waste per million British thermal unit
heat input of the hazardous waste.
D. Solid Fuel Boilers
The changes in the solid fuel boiler standards for existing sources
since proposal are:
------------------------------------------------------------------------
Proposed Final
Standard limit limit
------------------------------------------------------------------------
Mercury ([mu]g/dscm).............................. 10 11
Semivolatile Metals ([mu]g/dscm).................. 170 180
Low Volatile metals ([mu]g/dscm).................. 210 380
Alternative to the particulate matter standard: 170 180
Combined emissions of lead, cadmium and selenium
([mu]g/dscm).....................................
Alternative to the particulate matter standard: 210 380
Combined emissions of arsenic, beryllium,
chromium, antimony, cobalt, manganese, and nickel
([mu]g/dscm).....................................
------------------------------------------------------------------------
The changes in the solid fuel boiler standards for new sources
since proposal are:
------------------------------------------------------------------------
Proposed Final
Standard limit limit
------------------------------------------------------------------------
Mercury ([mu]g/dscm).............................. 10 11
Semivolatile Metals ([mu]g/dscm).................. 170 180
Low Volatile metals ([mu]g/dscm).................. 210 380
Alternative to the particulate matter standard: 170 180
Combined emissions of lead, cadmium and selenium
([mu]g/dscm).....................................
------------------------------------------------------------------------
E. Liquid Fuel Boilers
We redefined the liquid fuel boiler subcategory into two separate
boiler subcategories based on the heating value of the hazardous waste
they burn: Those that burn waste below 10,000 Btu/lb, those that burn
hazardous waste with a heating value of 10,000 Btu/lb or greater. See
Part Four, Section VI.D.2 of today's preamble for a complete
discussion.
The additional changes to the liquid fuel boiler standards for
existing sources since proposal are:
----------------------------------------------------------------------------------------------------------------
Final limit
-------------------------------------------------
Standard Proposed limit HW Fuel >= 10,000 Btu/
HW Fuel < 10,000 Btu/lb lb
----------------------------------------------------------------------------------------------------------------
Mercury (lb/MM Btu)................. 3.7E-6.................. 19 [mu]g/dscm.......... 4.2E-5
Particulate matter (gr/dscf)........ 0.032................... 0.035
Semivolatile metals (lb/MM Btu)..... 1.1E-5.................. 150 [mu]g/dscm......... 8.2E-5
Chromium (lb/MM Btu)................ 1.1E-4.................. 370 [mu]g/dscm......... 1.3E-4
Total chlorine (Lb/MM Btu).......... 2.5E-2.................. 31 ppmv................ 5.1E-2
Alternative to the particulate 1.1E-5.................. 150 [mu]g/dscm......... 8.2E-5
matter standard: Combined emissions
of lead, cadmium and selenium (lb/
MM Btu).
Alternative to the particulate 1.1E-4.................. 370 [mu]g/dscm......... 1.3E-4
matter standard: Combined emissions
of arsenic, beryllium, chromium,
antimony, cobalt, manganese, and
nickel (lb/MM Btu).
----------------------------------------------------------------------------------------------------------------
The changes in the liquid fuel boiler standards for new sources
since proposal are:
[[Page 59423]]
----------------------------------------------------------------------------------------------------------------
Final limit
Standard Proposed limit --------------------------------------------------
HW fuel < 10,000 Btu/lb HW fuel > 10,000 Btu/lb
----------------------------------------------------------------------------------------------------------------
Dioxin and Furan, dry APCD (ng TEQ/ 0.015 or temp control 0.40
dscm). < 400F for dry APCD.
Mercury (lb/MM Btu)................. 3.8E-7................. 6.8 [mu]g/dscm.......... 1.2E-6
Particulate matter (gr/dscf)........ 0.0076................. 0.0087
Semivolatile metals (lb/MM Btu)..... 4.3E-6................. 78 [mu]g/dscm........... 6.2E-6
Chromium (lb/MM Btu)................ 3.6E-5................. 12 [mu]g/dscm........... 1.4E-5
Total chlorine (lb/MM Btu).......... 7.2E-4................. 31 [mu]g/dscm........... 5.1E-2
Alternative to the particulate 4.3E-6................. 78 [mu]g/dscm \1\....... 6.2E-6 \1\
matter standard: Combined emissions
of lead, cadmium and selenium (lb/
MM Btu).
Alternative to the particulate 3.6E-5................. 12 [mu]g/dscm \2\....... 1.4E-5 \2\
matter standard: Combined emissions
of arsenic, beryllium, chromium,
antimony, cobalt, manganese, and
nickel (lb/MM Btu).
----------------------------------------------------------------------------------------------------------------
\1\ New or reconstructed liquid fuel boilers that process residual oil or liquid feedstreams that are neither
fossil fuel nor hazardous waste and that operate pursuant to the alternative to the particulate matter
standard must comply with the alternative emission concentration standard of 4.7 [mu]g/dscm, which is
applicable to lead, cadmium and selenium emissions attributable to all feedstreams (hazardous and
nonhazardous).
\2\ New or reconstructed liquid fuel boilers that process residual oil or liquid feedstreams that are neither
fossil fuel nor hazardous waste that operate pursuant to the alternative to the particulate matter standard
must comply with the alternative emission concentration standard of 12 [mu]g/dscm, which is applicable to
arsenic, beryllium, chrome, antimony, cobalt, manganese, and nickel emissions attributable to all feedstreams
(hazardous and nonhazardous).
F. Hydrochloric Acid Production Furnaces
The changes in the hydrochloric acid production furnace standards
for existing sources since proposal are:
------------------------------------------------------------------------
Standard Proposed limit Final limit
------------------------------------------------------------------------
Dioxin and Furans........... 0.4 ng TEQ/dscm..... Carbon Monoxide/
Total Hydrocarbons
and DRE standards
as surrogates.
Total chlorine.............. 14 ppmv or 99.9927% 150 ppmv or 99.923%
system removal system removal
efficiency. efficiency.
------------------------------------------------------------------------
The changes in the hydrochloric acid production furnace standards
for new sources since proposal are:
------------------------------------------------------------------------
Standard Proposed limit Final limit
------------------------------------------------------------------------
Dioxin and Furans........... 0.4 ng TEQ/dscm..... Carbon Monoxide/
Total Hydrocarbons
and DRE standards
as surrogates
Total chlorine.............. 1.2 ppmv or 99.9994% 25 ppmv or 99.987%
system removal system removal
efficiency. efficiency
------------------------------------------------------------------------
G. Dioxin/Furan Testing for Sources Not Subject to a Numerical Standard
Today's final rule requires that all sources not subject to a
numerical dioxin and furan standard perform a one time test to
determine their dioxin and furan emissions. See the discussion in Part
Four, Section VII.L.
In the proposed rule, this requirement was limited to solid fuel
boilers and those liquid fuel boilers with a wet or no air pollution
control system. The final rule expands this requirement to include
hydrochloric acid production furnaces and those lightweight aggregate
kilns that elect to comply with the temperature limit at the kiln exit
in lieu of the 0.20 ng TEQ/dscm dioxin/furan standard. Those sources
are not subject to a numerical dioxin/furan standard under the final
rule for reasons explained in Volume III of the Technical Support
Document, Sections 12 and 15. We note that sources not subject to a
numerical dioxin/furan emission standard are subject to the carbon
monoxide or hydrocarbon standards and the DRE standard as surrogates.
We are making no changes to the implementation of this requirement.
See the proposed rule at 69 FR at 21307 for more information.
III. Statistics and Variability
A. Using Statistical Imputation To Address Variability of Nondetect Values
In the final rule, we use a statistical approach to impute the
value of nondetect emissions and feedrate measurements to avoid
dampening of the variability of data sets when nondetect measurements
are assumed to be present at the detection limit.
At proposal, we assumed that nondetects (i.e., HAP levels in stack
emissions below the level of detection of the applicable analytic
method) are invariably present at the detection limit. Commenters on
the proposed rule stated, however, that assuming nondetects are present
at the detection limit dampens emissions variability--a consideration
necessary to reasonably ascertain sources' performance over time. This
could have significant practical consequence for those data sets (such
as the data base for liquid fuel boilers) dominated by nondetected
values. We agree with these commenters, and instead of making the
arbitrary assumption that all nondetected values are identical (which
[[Page 59424]]
in fact is highly unlikely), we are using a statistical methodology to
impute the value of nondetect measurements.
The imputation approach assigns a value for each nondetect
measurement in a data set within the possible range of values that
results in maximizing the 99th percentile upper prediction limit for
the data set. For example, the possible range of values for a
measurement that is 100% nondetect is between zero and the detection limit.
On February 4, 2005 we distributed a direct request for comments on
the imputation approach to major stakeholders. We respond to the
comments we received in Part Four, Section IV.D of today's notice.
B. Degrees of Freedom When Imputing a Standard Deviation Using the
Universal Variability Factor for Particulate Matter Controlled by a
Fabric Filter
The use of the universal variability factor to impute a standard
deviation for particulate emissions from sources controlled with a
fabric filter takes advantage of the empirical observation that the
standard deviation of particulate emissions from sources is positively
correlated to the average particulate emissions of sources. Based on
this observation, we use regression analysis to determine the best
fitting curve to explain the relationship of average value to standard
deviation.
In the final rule, we use the actual sample size, rather than an
assumed sample size of nine used at proposal, to determine the degrees
of freedom for the t-statistic to calculate the floor using the
standard deviation imputed from the universal variability factor for
particulate matter controlled by a fabric filter.
At proposal, we used eight degrees of freedom to identify the t-
statistic to account for within-test condition variability (i.e., run-
to-run variability) for standard deviations imputed from the universal
variability factor regression.\28\ This is because, on average, about
three test conditions with nine individual test runs are associated
with each source used to develop the regression curve.
---------------------------------------------------------------------------
\28\ USEPA, ``Draft Technical Support Document for HWC MACT
Standards, Volume III: Selection of MACT Standards,'' March 2004, p. 5-4.
---------------------------------------------------------------------------
A commenter states, however, that this approach can dramatically
understate variability when imputing a standard deviation for a source
with only three runs because the t-statistic is substantially higher
for 2 degrees of freedom than 8 degrees of freedom.
We agree with the commenter. Moreover, using the actual number of
runs to identify the t-statistic rather than assuming nine runs is
appropriate given that the true test condition average is less certain
for sources with only three runs, and thus there is less certainty in
the imputed standard deviation. The higher t-statistic associated with
a three-run data set reflects this uncertainty.
In addition, we include emissions data classified as ``normal'' in
the regression analysis for the final rule. At proposal, we used only
data classified as CT (i.e., highest compliance test condition in a
test campaign) or IB (i.e., a compliance test condition that achieved
lower emissions than another compliance test condition in the test
campaign). We conclude that normal data (i.e., emissions data that were
not used to establish operating limits and thus do not reflect
variability in controllable operating parameters) should also be
considered in the regression analysis because particulate matter
emissions are relatively insensitive to baghouse inlet loading and
operating conditions.\29\ Including normal emissions in the analysis
provides additional data to better quantify these devices' performance
variability.
---------------------------------------------------------------------------
\29\ USEPA, ``Technical Support Document for HWC MACT Standards,
Volume III: Selection of MACT Standards,'' September 2005, Section
5.3. See also Part Four, Section III.C of this preamble.
---------------------------------------------------------------------------
IV. Compliance Assurance for Fabric Filters, Electrostatic
Precipitators, and Ionizing Wet Scrubbers
The final rule provides additional requirements to clarify how you
determine the duration of periods of operation when the alarm set point
has been exceeded for a bag leak detection system or a particulate
matter detection system:
1. You must keep records of the date, time, and duration of each
alarm, the time corrective action was initiated and completed, and a
brief description of the cause of the alarm and the corrective action taken.
2. You must record the percent of the operating time during each 6-
month period that the alarm sounds.
3. In calculating the operating time percentage, if inspection of
the fabric filter, electrostatic precipitator, or ionizing wet scrubber
demonstrates that no corrective action is required, no alarm time is counted.
4. If corrective action is required, each alarm shall be counted as
a minimum of 1 hour.
The final rule also establishes revised procedures for establishing
the alarm set point if you elect to use a particulate matter detector
system in lieu of site-specific operating parameter limits for
compliance assurance for sources equipped with electrostatic
precipitators and ionizing wet scrubbers. The rule explicitly allows
you to maximize controllable operating parameters during the
comprehensive performance test to account for variability by, for
example, detuning the APCD or spiking ash. To establish the alarm set-
point, you may either establish the set-point as the average of the
test condition run average detector responses during the comprehensive
performance test or extrapolate the detector response after
approximating the correlation between the detector response and
particulate matter emission concentrations. You may extrapolate the
detector response up to a response value that corresponds to 50% of the
particulate matter emission standard or 125% of the highest particulate
matter concentration used to develop the correlation, whichever is
greater. To establish an approximate correlation of the detector
response to particulate matter emission concentrations you should use
as guidance Performance Specification-11 for PM CEMS (40 CFR Part 60,
Appendix B), except that you need conduct only 5 runs to establish the
initial correlation rather than a minimum of 15 runs required by PS-11.
The final rule also notes that an exceedance of a detector response
that corresponds to the particulate matter emission standard is not
evidence that the standard has been exceeded because the correlation is
an approximate correlation used for the purpose of compliance assurance
to determine when corrective measures must be taken. The correlation,
however, does not meet the requirements of PS-11 for compliance monitoring.
In addition, if you elect to use a particulate matter detection
system in lieu of site-specific control device operating parameter
limits on the electronic control device, the ash feedrate limit for
incinerators and boilers under Sec. 63.1209(m)(3) is waived. The ash
feedrate limit is waived because the particulate matter detection
system continuously monitors relative particulate matter emissions and
the alarm set point provides reasonable assurance that emissions will
not exceed the standard.\30\
---------------------------------------------------------------------------
\30\ Note that if your incinerator or boiler is equipped with a
fabric filter and you elect under Sec. 63.1206(c)(8)(i) to use a
particulate matter detection system in lieu of a bag leak detection
system for compliance assurance, the ash feedrate limit is waived.
The ash feedrate limit is not waived if you use a bag leak detection
system, however, because the alarm level may not ensure compliance
with the emission standard when you follow the concepts in the
Agency's guidance document on bag leak detection systems to
establish the alarm level.
---------------------------------------------------------------------------
[[Page 59425]]
Finally, you must submit an excessive exceedance notification
within 30 days of the date that the alarm set-point is exceeded more
than 5 percent of the time during any 6-month block period of time, or
within 30 days after the end of the 6-month block period, whichever is
earlier. The proposed rule would have required you to submit that
notification within 5 days of the end of the 6-month block period.
V. Health-Based Compliance Alternative for Total Chlorine
The final rule includes the following major changes to the proposed
health-based compliance alternative for total chlorine:
(1) You must use 1-hour Reference Exposure Levels (aRELs) rather
than 1-hour acute exposure guideline levels (AEGL-1) as the acute
health risk threshold metric when calculating 1-hour HCl-equivalent
emission rates;
(2) You must establish a long-term average chlorine feedrate limit
(i.e., 12 hour rolling average or an (up to) annual rolling average) as
the annual average HCl-equivalent emission rate limit divided by [1 -
system removal efficiency]. You establish the total chlorine system
removal efficiency during the comprehensive performance test. The
proposed rule would have required you to establish the long-term
average chlorine feedrate limit as the average of the test run averages
of the comprehensive performance test.\31\
---------------------------------------------------------------------------
\31\ Note that, as a practical matter, most sources must
establish the chlorine feedrate limit as the average of the test run
average feedrate limit during the comprehensive performance test to
demonstrate compliance with the semivolatile emission standard. This
is because chlorine feedrate is a compliance assurance parameter for
the semivolatile metal emission standard. That feedrate limit is
based on a 12-hour rolling average. To ensure compliance with the
annual average HCl-equivalent emission rate limit, however, that
feedrate limit cannot exceed the value calculated as the annual
average HCl-equivalent emission rate limit divided by [1 - system
removal efficiency], where you demonstrate the total chlorine system
removal efficiency during the performance test.
---------------------------------------------------------------------------
(3) At proposal, we requested comment on whether and how to
establish a short-term chlorine feedrate limit to ensure that the acute
exposure Hazard Index of 1.0 is not exceeded. See 69 FR at 21304. We
conclude for the final rule that a 1-hour rolling average feedrate
limit may be needed for some situations (i.e., if chlorine feedrates
can vary substantially during the averaging period for the long-term
feedrate limit and potentially result in an exceedance of the 1-hour
average HCl-equivalent emission rate limit). Accordingly, although your
eligibility for the health-based compliance alternatives is based on
annual average HCl-equivalent emissions, you must determine considering
prescribed criteria whether your 1-hour HCl-equivalent emission rate
may exceed the national exposure standard (i.e., Hazard Index not
exceeding 1.0 considering the maximum 1-hour average ambient
concentration of hydrogen chloride and chlorine at an off-site receptor
location\32\) and thus may exceed the 1-hour average HCl-equivalent
emission rate limit absent an hourly rolling average limit on the
feedrate of chlorine. If the acute exposure standard may be exceeded,
you must establish an hourly rolling average chlorine feedrate limit as
the 1-hour HCl-equivalent emission rate limit divided by [1 - system
removal efficiency]. You establish the system removal efficiency during
the comprehensive performance test.
---------------------------------------------------------------------------
\32\ Under the site-specific risk assessment approach to
demonstrate eligibility, you must consider locations where people
reside and where people congregate for work, school, or recreation.
---------------------------------------------------------------------------
(4) When calculating HCl-equivalent emission rates, rather than
partitioning total chlorine emissions between chlorine and HCl (i.e.,
the Cl2/HCl volumetric ratio) based on the comprehensive
performance test as proposed, you must establish the Cl2/HCl
volumetric ratio used to calculate the annual average HCl-equivalent
emission rate based on the historical average ratio from all regulatory
compliance tests. You must establish the Cl2/HCl volumetric
used to calculate the 1-hour average HCl-equivalent emission rate as
the highest of the historical ratios from all regulatory compliance
tests. The rule allows you to exclude ratios from historical compliance
tests where the emission data may not be representative of the current
Cl2/HCl ratio for reasons such as changes to the design or
operation of the combustor or biases in measurement methods. The rule
also explicitly allows the permitting authority to require periodic
emissions testing to obtain a representative average and maximum ratio;
(5) The look-up table analysis has been refined by presenting
annual average and 1-hour HCl-equivalent emission rate limits as a
function of stack height, stack diameter, and distance to property
line. In addition, separate look-up tables are presented for flat
terrain and simple elevated terrain;
(6) The proposed rule required approval of the eligibility
demonstration before you could comply with the alternative health-based
emission limits for total chlorine. Under the final rule, if your
permitting authority has not approved your eligibility demonstration by
the compliance date, and has not issued a notice of intent to
disapprove your demonstration, you may nonetheless begin complying, on
the compliance date, with the annual average HCl-equivalent emission
rate limits you present in your eligibility demonstration. In addition,
if your permitting authority issues a notice of intent to disapprove
your eligibility demonstration, the authority will identify the basis
for that notice and specify how much time you will have to submit
additional information or to comply with the MACT total chlorine
standards. The permitting authority may extend the compliance date of
the total chlorine standards to allow you to make changes to the design
or operation of the combustor or related systems as quickly as
practicable to enable you to achieve compliance with the MACT total
chlorine standards;
(7) We have revised the approach for determining chlorine emissions
if you feed bromine or sulfur during the comprehensive performance test
at levels higher than those specified in Sec. 63.1215(e)(3)(ii)(B).
Under the final rule, 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 chlorine and
hydrogen chloride. You must determine your chlorine emissions to be the
higher of: (1) The value measured by Method 26/26A, or an equivalent
method; or (2) the value calculated by difference between the combined
hydrogen chloride and chlorine levels measured by Method 26/26a, or an
equivalent method, and the hydrogen chloride measurement from EPA
Method 320/321 or ASTM D 6735-01, or an equivalent method; and
(8) The proposed rule would have required you to conduct a new
comprehensive performance test if you planned to make changes to the
facility that would lower the annual average HCl-equivalent emission
rate limit. Under the final rule, you would be required to conduct a
performance test as a result of a planned change only for a change to
the design, operation, or maintenance of the combustor that could
affect the system removal efficiency for total chlorine if the change
could reduce the system removal efficiency, or if the change would
increase the system removal efficiency and you elect to increase the
feedrate limits on total chlorine and chloride.
[[Page 59426]]
Part Four: What Are the Responses to Major Comments?
I. Database
A. Revisions to the EPA's Hazardous Waste Combustor Data Base
Comment: Several commenters identify sources which have ceased
operations as a hazardous waste combustor and should be removed from
EPA's data base.
Response: We agree with commenters that data and information from
sources no longer burning hazardous waste should not be included in our
hazardous waste combustor data base and should not be used to calculate
the MACT standards. We consider any source that has initiated RCRA
closure procedures and activities as a source that is no longer burning
hazardous waste. This data handling decision is consistent with the
approach we used in the 1999 final rule. See 64 FR at 52844. As we
stated in that rule, ample emissions data remain to support calculating
the MACT standards without using data from sources that no longer burn
hazardous waste.
As a result, we removed the following former hazardous waste
combustors from the data base: the Safety-Kleen incinerator in
Clarence, New York, the Dow Chemical Company incinerators in Midland,
Michigan, and LaPorte, Texas, the two Holcim wet process cement kilns
in Holly Hill, South Carolina, the Dow Chemical Company liquid fuel-
fired boiler in Freeport, Texas, the Union Carbide liquid fuel-fired
boilers in Hahnville, Louisiana, and Texas City, Texas, and six Dow
Chemical Company hydrochloric production furnaces in Freeport, Texas.
We are retaining, however, Solite Corporation's lightweight
aggregate facility in Cascade, Virginia, in the data base. Even though
the facility recently initiated RCRA closure procedures, this data
handling decision differs from those listed in the preceding paragraph
because Solite Corporation provided this new information in February
2005 while information on the other closures was reported or available
to us in 2004. Because we cannot continually adjust our data base and
still finalize this rulemaking by the court-ordered deadline, we
stopped making revisions to the data base in late 2004. Additional
facility changes after that date, like Solite Corporation's Cascade
facility closure, simply could not be incorporated.
Comment: One commenter identifies a source in EPA's data base that
should be classified as a boiler instead of a hydrochloric acid
production furnace.
Response: We agree with the commenter. In today's rule, Dow
Chemical Company's boiler F-2820, located in Freeport, Texas, is
reclassified in our data base as a boiler. This source is identified as
unit number 2020 in our data base.
B. Use of Data From Recently Upgraded Sources
Comment: Many commenters recommend that EPA remove from the data
base (or not consider for standards-setting purposes) emissions data
from sources that upgraded their emissions controls to comply with the
promulgated emission standards of either the 1999 rule or the 2002
interim standards. Several commenters also state that any emissions
data that were obtained or used to demonstrate compliance with the
promulgated standards of 1999 or 2002 should not be used for standard-
setting purposes by the Agency. That is, EPA must evaluate the source
category as it existed at the beginning of the rule development process
and not after emissions controls are later added to comply with the
1999 or 2002 standards. Several commenters also state that EPA is only
partly correct in claiming that the interim standards are not MACT
standards because the interim standards were established and considered
to be MACT until the Court issued its opinion in July 2001. Until that
time, sources proceeded to upgrade their facilities to achieve the
standards promulgated in 1999. The rationale for these recommendations
is threefold: (1) Use of the data unfairly ignores the MACT-driven
reductions already achieved by some sources; (2) it is contrary to
sound public policy to use data from upgraded facilities to ``ratchet
down'' the MACT floors to a level more stringent because these sources
would not have increased their level of performance but for the legal
obligation to comply with the standards; and (3) EPA's reliance on
National Lime Ass'n v. EPA, 233 F.3d 625, 640 (D.C. Cir. 2000), for the
proposition that the motivation for a source's performance is legally
irrelevant in developing MACT floor levels is misplaced because that
case involved the initial MACT standard setting process, and not a
subsequent rule.
One commenter agrees with EPA's proposed position and states that
use of data from sources that have upgraded is not only appropriate,
but also required by the Clean Air Act. This commenter states that the
actual performance of sources that have upgraded their emissions
equipment--to meet the 1999 standards or for any reason--is reflected
only by the most recently generated emissions data for the source.
Thus, the Clean Air Act requires EPA to use the most recently generated
data available to it and precludes the Agency from using older, out-of-
date performance data.
EPA also received several comments stating that the language of
section 112(d)(3)(A) of the Clean Air Act informs how the Agency should
consider emissions data from sources that conducted testing after that
1999 rule was promulgated. One commenter states that the only data
which should not be used in calculating the MACT floors are from
sources that are subject to lowest achievable emission rates (LAER).
Thus, the commenter states, Congress considered the possibility of
significant and recent upgrades, and concluded that EPA should use up-
to-date data to reflect source's performance, but must exclude certain
sources from the floor calculation if their upgrades were of a specific
degree and were accomplished within a specific period of time. Another
commenter states that Congress did not intend to pile technology upon
technology as confirmed by section 112(d)(3)(A) that specifically
excludes sources that implemented LAER from consideration when
establishing section 112(d) standards. Thus, the commenter states,
considering data from sources that have upgraded violates both the
language and intent of the Clean Air Act. Another commenter states
that, while Congress no doubt contemplated that EPA should use all
available emissions information in setting initial MACT standards,
neither the statute nor the legislative history suggest that follow-up
MACT rulemakings require the use of data reflecting compliance efforts
with previous MACT standards or interim standards.
Response: As proposed, EPA maintains its position on use of post-
1999 emissions data. The statute indicates that EPA is to base MACT
floors on performance of sources ``for which the Administrator has
emissions information.'' Section 112(d)(3)(A); CKRC, 255 F. 3d at 867.
There can be no dispute that post-1999 performance data in EPA's
possession fits this description. We also reiterate that the motivation
for the control reflected in data available to us is irrelevant. See 69
FR at 21217-218. We further agree with those commenters who pointed out
that Congress was explicit when it wanted certain emissions information
(i.e., sources operating pursuant to a LAER standard) excluded from
consideration in establishing floors. There is, of course, no such
enumerated exception
[[Page 59427]]
for sources that have upgraded their performance for other reasons.
We also do not agree with those commenters arguing (with respect to
the standards for the Phase 1 sources (incinerators, cement kilns, and
lightweight aggregate kilns)) in effect that the present rulemaking
involves revision of an existing MACT standard. If this were indeed a
revision of a MACT standard under section 112(d)(6), then EPA would not
redetermine floor levels. See 70 FR at 20008 (April 15, 2005). However,
EPA has not to date promulgated valid MACT floors or valid MACT
standards for these sources. The 1999 standards do not reflect MACT, as
held by the CKRC court. The interim standards likewise do not reflect
MACT, but were designed to prevent a regulatory gap and were described
as such from their inception. 67 FR at 7693 (Feb. 13, 2002); see also
Joint Motion of all Parties for Stay of Issuance of Mandate in case no.
99-1457 (October 19, 2001), pp. 11-12 (``The Parties emphasize that the
contemplated interim rule is in the nature of a remedy. It would not
respond to the Court's mandate regarding the need to demonstrate that
EPA's methodology reasonably predicts the performance of the average of
the best performing twelve percent of sources (or best-performing
source). EPA intends to address those issues in a subsequent rule,
which will necessarily require a longer time to develop, propose, and
finalize.'') EPA consequently believes that it is adopting in this rule
the initial section 112(d) MACT standards for hazardous waste burning
incinerators, cement kilns, and lightweight aggregate kilns, and that
the floor levels for existing sources are based, as provided in section
112(d)(3), on performance of those sources for which EPA has
``emissions information.''
However, we disagree with the comment that we must make exclusive
use of the most recent information from hazardous waste combustion
sources. There is no such restriction in section 112(d)(3). EPA has
exhaustively examined all of the data in its possession for all source
categories covered by this rule, and determined (and documented) which
data are suitable for evaluating sources' performance.
C. Correction of Total Chlorine Data to Address Potential Bias in Stack
Measurement Method
Comment: Several commenters state that EPA's proposed total
chlorine standards of 1.5 ppm for existing incinerators and 0.18 ppm
for new incinerators are based on biased data of indeterminate quality
and are unachievable. Commenters assert that Method 26A and its RCRA
equivalent, SW 846 Method 0050, have a negative bias at concentrations
below 20 ppmv when used on stacks controlled with wet scrubbers.
Commenters cite two recurring situations when this bias is likely to
occur: (1) hydrogen chloride dissolving in condensed moisture in the
sampling train; and (2) hydrogen chloride reacting with alkaline
compounds from the scrubber water that are collected on the filter
ahead of the impingers.
Commenters are particularly concerned about the negative bias
associated with stack gas containing substantial water vapor.
Commenters note that EPA found in a controlled laboratory study by
Steger \33\ that the bias is between 17 and 29 percent at stack gas
moisture content of 7 to 9 percent. This stack gas moisture is much
less than the nominal 50% moisture contained in some hazardous waste
combustor stacks according to the commenters. Commenters believe this
is why EPA's Method 0050, which was used to gather most of the data in
the HWC MACT data base, states in Section 1.2 that ``this method is not
acceptable for demonstrating compliance with HCl emission standards
less than 20 ppm.''
---------------------------------------------------------------------------
\33\ Steger, J.L., et al, ``Laboratory Evaluation of Method 0050
for Hydrogen Chloride'', Proc of 13th Annual Incineration
Conference, Houston, TX, May 1994.
---------------------------------------------------------------------------
Moreover, commenters state that the procedures in Method 0050 to
address the negative bias caused by condensed moisture were not
followed for many RCRA compliance tests. The method uses an optional
cyclone to collect moisture droplets, and requires a 45 minute purge of
the cyclone and sampling train to recover hydrogen chloride from water
collected by the cyclone and any condensed moisture in the train. The
cyclone is not necessary if the stack gas does not contain water
droplets. According to commenters, the cyclone and subsequent purge
were often not used in the presence of water droplets because a
potential low bias below 20 ppmv was irrelevant when demonstrating
compliance with emission standards on the order of 100 ppmv. There was
no need for the extra complexity and expense of using a cyclone and
train purge given the purpose of the test. Although the data were
acceptable for their intended purpose, commenters conclude that the
data are not useful for establishing standards below 20 ppmv.
For these reasons, commenters suggest that EPA not consider total
chlorine measurements below 20 ppmv when establishing the standards.
Response: For the reasons discussed below, we corrected all total
chlorine measurements in our data base for all source categories that
were below 20 ppmv to 20 ppmv to establish the total chlorine floors.
Moreover, to address run-to-run variability given that all runs for
several data sets are now corrected to 20 ppmv, we impute a run
standard deviation based on a regression analysis of run standard
deviation versus total chlorine concentration for sources with total
chlorine measurements greater than 20 ppmv. This is the same approach
we used to impute variability from sources using fabric filters when
determining the particulate matter MACT floors.
Effect of Moisture Vapor. Commenters imply that stack gas with high
levels of gas phase water vapor will inherently be problematic,
particularly at emissions less than 20 ppmv. There is no basis for
claiming that water vapor, per se, causes a bias in SW-846 Method 0050
or its equivalent, Method 26A. Condensed moisture (i.e., water
droplets), however, can cause a bias because it can dissolve hydrogen
chloride in the sampling train and prevent it from being captured in
the impingers if the sampling train is not properly purged. Water
droplets can potentially be present due to entrainment from the wet
scrubber, condensation in cooler regions of the stack along the stack
walls, and entrainment from condensed moisture dripping down the stack
wall across the inlet duct opening.
Although Method 0050 addresses the water droplet issue by use of a
cyclone and 45 minute purge, the Steger paper (Ibid.) concludes that a
45 minute purge is not adequate to evaporate all water collected by the
cyclone in stacks with a total moisture content (vapor and condensed
moisture) of 7 to 9%. At those moisture levels, Steger documented the
negative bias that commenters reference. Steger's recommendation was to
increase the heat input to the sample train by increasing the train and
filter temperature from 120C (248F) to 200C (392F). We agree that
increasing the probe and filter temperature will provide a better
opportunity to evaporate any condensed moisture, but another solution
to the problem is to require that the post-test purge be run long
enough to evaporate all condensed moisture. That is the approach used
by Method 26A, which EPA promulgated after Method 0050, and which
sources must use to demonstrate compliance with the final standards.
Method 26A uses an extended purge time rather than
[[Page 59428]]
elevating the train temperature to address condensed moisture because
that approach can be implemented by the stack tester at the site
without using nonstandard equipment.
We attempted to quantify the level of condensed moisture in the
Steger study and to compare it to the levels of condensed moisture that
may be present in hazardous waste combustor stack gas. This would
provide an indication if the bias that Steger quantified with a 45
minute purge might also be applicable to some hazardous waste
combustors. We conclude that this comparison would be problematic,
however, because: (1) given the limited information available in the
Steger paper, it is difficult to quantify the level of condensed
moisture in his gas samples; and (2) we cannot estimate the levels of
condensed moisture in hazardous waste combustor stack gas because, even
though condensed moisture may have been present during a test, method
protocol is to report the saturation moisture level only (i.e., the
amount of water vapor present), and not the total moisture content
(i.e., both condensed and vapor phase moisture).
We can conclude, however, that, if hazardous waste combustor stack
gas were to contain the levels of condensed moisture present in the gas
that Steger tested, the 45 minute purge required by Method 0050 would
not be sufficient to avoid a negative bias. We also conclude that this
is potentially a practical issue and not merely a theoretical concern
because, as commenters note, hazardous waste combustors that use wet
scrubbers are often saturated with water vapor that will condense if
the flue gas cools.
Data from Wet Stacks When a Cyclone Was Not Used. Commenters state
that Method 0050 procedures for addressing water droplets (adequate or
not, as discussed above) were not followed in many cases because a low
bias below 20 ppmv was not relevant to demonstrating compliance with
standards on the order of 100 ppmv. We do not know which data sets may
be problematic because, as previously stated, the moisture
concentration reported was often the saturation (vapor phase only)
moisture level and not the total (vapor and liquid) moisture in the
flue gas. We also have no documentation that a cyclone was used--even
in situations where the moisture content was documented to be above the
dew point. We therefore conclude that all data below 20 ppmv from
sources controlled with a wet scrubber are suspect and should be
corrected.
Potential Bias Due to Filter Affinity for Hydrogen Chloride.
Studies by the American Society of Testing and Materials indicate that
the filter used in the Method 0050 train (and the M26/26A trains) may
adsorb/absorb hydrogen chloride and cause a negative bias at low
emission levels. (See ASTM D6735-01, section 11.1.3 and ``note 2'' of
section 14.2.3) This inherent affinity for hydrogen chloride can be
satisfied by preconditioning the sampling train for one hour. None of
the tests in our database were preconditioned in such a manner.
We are normally not concerned about this type of bias because we
would expect the bias to apply to all sources equally (e.g., wet or dry
gas) and for all subsequent compliance tests. In other words, we are
ordinarily less concerned if a standard is based on biased data, as
long as the means by which the standard was developed and the means of
compliance would experience identical bias.
However, we did correct the wet gas measurements below 20 ppmv to
address the potential low bias caused by condensed moisture. This
correction would also correct for any potential bias caused by the
filter's inherent affinity for hydrogen chloride. This results in a
data set that is partially corrected for this issue--sources with wet
stacks would be corrected for this potential bias while sources with
dry stacks would not be corrected. To address this unacceptable mix of
potentially biased and unbiased data (i.e., dry gas data biased due to
affinity of filter for hydrogen chloride and wet gas data corrected for
condensed moisture and affinity of filter for hydrogen chloride), we
also correct total chlorine measurements from dry gas stacks (i.e.,
sources that do not use wet scrubbers).
Deposition of Alkaline Particulate on the Filter. Commenters are
also concerned that hydrogen chloride may react with alkaline compounds
from the scrubber water droplets that are collected on the filter ahead
of the impingers. Commenters suggest this potential cause for a low
bias at total chlorine levels below 20 ppmv is another reason not to
use measurements below 20 ppmv to establish the standards.
Although alkaline particulate deposition on the method filter
causing a negative bias is a much greater concern for sources that have
stack gas containing high levels of alkaline particulate (e.g., cement
kilns, sources equipped with dry scrubbers), we agree with commenters
that this may be of concern for all sources equipped with wet
scrubbers. Our approach to correct all data below 20 ppmv addresses
this concern.
Decision Unique to Hazardous Waste Combustors. We note that the
rationale for our decision to correct total chlorine data below 20 ppmv
to account for the biases discussed above is unique to the hazardous
waste combustor MACT rule. Some sources apparently did not follow
Method 0050 procedures to minimize the low bias caused by condensed
moisture for understandable reasons. Even if sources had followed
Method 0050 procedures to minimize the bias (i.e., cyclone and 45
minute purge) there still may have been a substantial bias because of
insufficient purge time, as Steger's work may indicate. We note that
the total chlorine stack test method used by sources other than
hazardous waste combustors--Method 26A--requires that the cyclone and
sampling train be purged until all condensed moisture is evaporated. We
believe it is necessary to correct our data below 20 ppmv data because
of issues associated exclusively with Method 0050 and how it was used
to demonstrate compliance with these sources.
Determining Variability for Data at 20 ppmv. Correcting those total
chlorine data below 20 ppmv to 20 ppmv brings about a situation
identical to the one we confronted with nondetect data. See Part Four,
Section V.B. below. The MACT pool of best performing source(s) for some
data sets is now comprised of largely the same values. This has the
effect of understating the variability associated with these data.
To address this concern, we took an approach similar to the one we
used to determine variability of PM emissions for sources equipped with
a fabric filter. In that case, we performed a linear regression on the
data, charting variability against emissions, and used the variability
that resulted from the linear regression analysis as the variability
for the sources average emissions. In this case, most or all of the
incinerator and liquid fuel boiler sources in the MACT pool have
average emissions at or near 20 ppmv. We therefore performed a linear
regression on the total chlorine data charting average test condition
results above 20 ppmv against the variability associated with that test
condition. The variability associated with 20 ppmv was the variability
we used for incinerator and liquid fuel boiler data sets affected by
the 20 ppmv correction.
We also considered using the statistical imputation approach we
used for nondetect values. See discussion in Section IV.B below. The
statistical imputation approach for correcting data below 20 ppmv
without dampening variability would involve imputing a value between
the reported value and 20
[[Page 59429]]
ppmv because the ``true'' value of the biased data would lie in this
interval. This approach would be problematic, however, given that many
of the reported values were much lower than 20 ppmv; our statistical
imputation approach would tend to overestimate the run to run
variability. Consequently, we conclude that a regression analysis
approach is more appropriate. A regression analysis is particularly
pertinent in this situation because: (1) We consider data above 20 ppmv
used to develop the regression to be unbiased; and (2) all the
corrected data averages for which we are imputing a standard deviation
from the regression curve are at or near 20 ppmv. Thus, any potential
concern about downward extrapolation from the regression would be
minimized.
We note that, although a regression analysis is appropriate to
estimate run-to-run variability for the corrected total chlorine data,
we could not use a linear regression analysis to address variability of
nondetect values. To estimate a standard deviation from a regression
analysis, we would need to know the test condition average emissions.
This would not be feasible, however, because some or all of the run
measurements for a test condition are nondetect. In addition, we are
concerned that a regression analysis would not accurately estimate the
standard deviation at low emission levels because we would have to
extrapolate the regression downward to levels where we have few
measured data (i.e., data other than nondetect). Moreover, the
statistical imputation approach is more suitable for handling
nondetects because the approach calculates the run-to-run variability
by taking into account the percent nondetect for the emissions for each
run.\34\ A regression approach would be difficult to apply particularly
in the case of test conditions containing partial nondetects or a mix
of detect and nondetect values. Given these concerns with using a
regression analysis to estimate the standard deviation of test
conditions with runs that have one or more nondetect (or partial
nondetect) measurements, we conclude that the statistical imputation
approach best assures that the calculated floor levels account for run-
to-run emissions variability.
---------------------------------------------------------------------------
\34\ For multi-constituent HAP (e.g. SVM) the emissions for a
run could be comprised of fully detected values for some HAP and
detection limits for other HAP that were nondetect.
---------------------------------------------------------------------------
Compliance with the Standards. The final standards are based on
data that were corrected to address specific issues concerning these
data. See the above discussion regarding stack gas moisture, filter
affinity for hydrogen chloride, and alkaline compound reactions with
hydrogen chloride in the sampling train.
Sources must demonstrate compliance using a stack test method that
also addresses these issues. Sources with wet stacks must use Method
26A and follow those procedures regarding the use of a cyclone and the
purging of the system whenever condensed moisture may be present in the
sampling system.
Finally, all sources--those with either wet or dry gas--should
precondition the sampling train for one hour prior to beginning the
test to satisfy the filter's affinity for hydrogen chloride. The
permitting authority will ensure that sources precondition the sample
train (under authority of Sec. 63.1209(g)(2)) when they review and
approve the performance test plan.
D. Mercury Data for Cement Kilns
Comment: Several commenters state that EPA's data base of mercury
emissions data (and associated feed concentrations of mercury in the
hazardous waste) are unrepresentative and unsuitable for use in
determining MACT standards for cement kilns. These comments are
supported by an extensive amount of data submitted by the cement
manufacturing industry including three years of data documenting day-
to-day levels of mercury in hazardous waste fuels fired to all 14
hazardous waste burning cement kilns.\35\ The commenters recommend that
EPA use the commenter-submitted data as the basis for assessing cement
kilns' performance for control of mercury because it is the most
complete and representative data available to EPA.
---------------------------------------------------------------------------
\35\ See docket item OAR-2004-0022-0049.
---------------------------------------------------------------------------
Response: We agree that the commenter-submitted mercury data are
more representative than those we used at proposal. First, these data
represent a significantly larger and more comprehensive dataset
compared to the one used to support the proposed mercury standard. The
commenter-submitted data document the day-to-day levels of mercury in
hazardous waste fired to all cement kilns for a three year period
covering 1999 to 2001. In total, approximately 20,000 measurements of
the concentration of mercury in hazardous waste are included in the
dataset. When considered in whole, these data describe the performance
(and variability thereof) of all cement kilns for the three year period
because each measurement represents the mercury concentration in the
burn tank used to fire the kiln over the course of a day's operation
(or longer period).\36\ In comparison, the data used to support the
proposed floor level consisted of a much smaller dataset of
approximately 50 test conditions representing a snapshot of performance
somewhere in the range of normal operations, with each test condition
representing a relatively short period of time (e.g., several
hours).\37\ As discussed at proposal, we were concerned regarding the
representativeness of this smaller dataset. See 69 FR at 21251. In
addition, the commenter-submitted dataset allows us to better evaluate
the only mercury control technique used by existing hazardous waste
burning cement kilns--controlling the feed concentration of mercury in
the hazardous waste. The commenters have demonstrated convincingly that
the mercury dataset used at proposal does not properly show the range
of performance and variability in performance these cement kilns
actually experience, while the significantly more robust dataset
submitted by commenters does illustrate this variability. Thus, we
conclude the larger commenter-submitted dataset is superior to EPA's
smaller testing dataset.
---------------------------------------------------------------------------
\36\ Mercury is a volatile compound at the typical operating
temperatures of the air pollution control devices used by cement
kilns (i.e., baghouses and electrostatic precipitators). Most of the
mercury exits the cement kiln system as volatile stack emissions,
with a smaller fraction partitioning to the clinker product or
cement kiln dust. Thus, in general, there is a proportional
relationship between the mercury concentration in the hazardous
waste and stack emissions of mercury (i.e., as the mercury
concentration in hazardous waste increases (assuming mercury
concentrations in other inputs such as raw materials and fossil
fuels (coal) and other factors remain constant), emissions of
mercury will correspondingly increase).
\37\ EPA's dataset for mercury for cement kilns is not like the
RCRA compliance test emission data for other HAPs where each source
designs the compliance test such that the operating limits it
establishes account for the variability it expects to encounter
during its normal operations (e.g., semi- and low volatile metals).
This is not necessarily true for mercury for cement kilns as shown
in our analysis of our mercury dataset at proposal. See 69 FR at 21251.
---------------------------------------------------------------------------
We note that our MACT floor analysis of the commenter-submitted
dataset to determine which sources are the best performers and to
identify a mercury standard for cement kilns is discussed in the
background document.\38\ Additional discussion of issues related to the
mercury standard for cement kilns is found in Part Four, Section VI.B
of the preamble.
---------------------------------------------------------------------------
\38\ USEPA, ``Technical Support Document for HWC MACT Standards,
Volume III: Selection of MACT Standards,'' Sections 7.5.3 and 11.0,
September 2005.
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[[Page 59430]]
E. Mercury Data for Lightweight Aggregate Kilns
Comment: One commenter, an owner and operator of seven of the nine
operating lightweight aggregate kilns, states that the mercury dataset
used by EPA at proposal is a limited and unrepresentative snapshot of
performance of their seven kilns. To support their position that the
snapshot emissions data are unrepresentative, the commenter submitted
eight months of data documenting levels of mercury in hazardous waste
fuels fired to their lightweight aggregate kilns.\39\
---------------------------------------------------------------------------
\39\ See docket items OAR-2004-0022-0270 and OAR-2004-0022-0333.
---------------------------------------------------------------------------
Response: We agree with the commenter that their mercury data
submission is more representative than those used at proposal. As
discussed in a notice for public comment sent directly to certain
commenters,\40\ the commenter-submitted dataset documents the day-to-
day levels of mercury in hazardous waste fuels fired to Solite
Corporation's Arvonia kilns between October 2003 and June 2004. The
dataset consists of over 310 measurements of the concentration in
mercury in hazardous waste. Each measurement represents the mercury
concentration of the burn tank used to fire the kiln over the course of
a day's operation (or longer period). In comparison, the data used to
support the proposed floor level consisted of a smaller dataset of 15
test conditions.
---------------------------------------------------------------------------
\40\ See docket item OAR-2004-0022-0370.
---------------------------------------------------------------------------
The nature of the mercury data submitted by the commenter is the
same as we received for the cement kiln category discussed in the
preceding section. For similar reasons, we accept the more
comprehensive commenter-submitted dataset as one that better shows the
range of performance and variability in performance for these
lightweight aggregate kilns. One notable difference, however, is that
the commenter submitted mercury data only for its company (representing
seven of nine lightweight aggregate kilns). Thus, we received no data
documenting day-to-day levels of the concentration of mercury in
hazardous waste fuels for the other two lightweight aggregate kilns
owned by a different company. For these two lightweight aggregate
kilns, we continue to use available data available in our database.\41\
---------------------------------------------------------------------------
\41\ Unlike that is available for the commenter's kilns, we note
that we have compliance test emissions data, which is designed to
maximize operating parameters (e.g., HAP feedrates) that affect
emissions, for the other two kilns. For additional discussion on how
these data were analyzed in conjunction with the commenter-submitted
data, see the document ``Technical Support Document for HWC MACT
Standards, Volume III: Selection of MACT Standards,'' Section 7.5.3
and 12.0, September 2005.
---------------------------------------------------------------------------
Comment: One commenter opposes the use of the commenter-submitted
mercury data because EPA would be uncritically accepting a limited and
select data set from a commenter with a direct interest in the outcome
of its use. Instead, the commenter suggests EPA use its section 114
authority to obtain all data that are available, not just the data
selected by that commenter.
Response: We disagree that we uncritically accepted the commenter-
submitted mercury data. The reason the commenter submitted data
collected between October 2003 and June 2004 is that the facility was,
prior to October 2003, in the process of upgrading its on-site analysis
equipment. One outcome of this laboratory upgrade was its capability to
detect mercury in hazardous waste at lower concentrations. Prior to the
upgrade, the facility's on-site laboratory was capable of detecting
mercury in the hazardous waste at a concentration of approximately 2
ppmw, which is a level such that the vast majority of measurements
would neither be detected nor useful for identifying best performers
and their level of performance.\42\ The June 4, 2004 cutoff date
represents a practicable date that measurements could still be
incorporated into the commenter's public comments to the proposed rule,
which were submitted on July 6, 2004. Finally, the commenter provided
all waste fuel measurements during this period and states reliably that
no measurements made during this period were selectively excluded.\43\
---------------------------------------------------------------------------
\42\ A mercury concentration of 2 ppmw in the hazardous waste
corresponds to a stack concentration of approximately 200 [mu]g/
dscm, which is well above the interim standard of 120 [mu]g/dscm for
mercury.
\43\ See also docket items OAR-2004-0022-0233 and OAR-2004-0022-0367.
---------------------------------------------------------------------------
We also reject the commenter's suggestion that we use our authority
under section 114 of the Clean Air Act to obtain additional hazardous
waste mercury concentration data from the facility. There is no
obligation for us to gather more performance data, given that the
statute indicates that we are to base floor levels on performance of
sources ``for which the Administrator has emissions information.''
Section 112(d)(3)(A); CKRC, 255 F. 3d at 867. In addition, given our
concerns about the usefulness of measurements with high detection
limits discussed above, the collection of additional data prior to the
laboratory upgrade would not be productive. When balanced against the
expenditure of significant resources, both in time and level of effort,
to collect several more months of data, we conclude that obtaining
additional mercury measurements is unnecessary because the available
eight months of data--including over 310 individual measurements--
represent a significant amount of data that we judge to be adequately
reflective of the source's performance and variability in performance.
F. Incinerator Database
Comment: Commenters state that many of the top performers (e.g.,
3011, 3015, 3022, 349) dilute emission concentrations in the stack by
burning natural gas to initiate reactive waste (e.g., explosives,
inorganic hydrides) or to decontaminate inert material. Commenters do
not believe these units should be considered ``representative'' of the
overall incinerator source category and should not be used to establish
standards for incinerators combusting primarily organic wastes.
Response: Source 3022 has closed and has been removed from the
database. Emission data from source #3015 (ICI explosives) has
been excluded for purposes of calculating the particulate matter floor
because the test report indicates this source was primarily feeding
scrap metal, which we conclude to be an atypical waste stream from a
particulate matter compliance perspective.\44\
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\44\ We did not have ash feed data for source 3015. We
acknowledge that ash feed control levels do not significantly affect
particulate matter emissions from sources equipped with baghouses.
However, in this instance, the particulate matter emissions from
this source may not be representative because this source may not
have been feeding any appreciable levels of ash given that scrap
metal feeds generally would not contribute to the ash loading into
the baghouse.
---------------------------------------------------------------------------
The sources identified by the commenter are among the best
performing sources in two instances. Source 3011 is the second ranked
best performer for the particulate matter standard. This source is
among the best performers for particulate matter because it uses a
state-of-the art baghouse that is equipped with Teflon coated bags.
There is no evidence to suggest that this source was diluting its
particulate matter emissions. We acknowledge that we do not have ash
feed data for the test conditions that were used in the particulate
matter standard analysis. However, this source had the third and fourth
highest metal feed control levels among all the sources used in the
MACT analysis for the semivolatile and low volatile metal
[[Page 59431]]
standards.\45\ We therefore conclude that it is appropriate to include
this source in the MACT analysis that determines the relevant best
performers for particulate matter.
---------------------------------------------------------------------------
\45\ We note that feed control levels are normalized based on
each source's gas flowrate. The feed control levels used to assess
performance are therefore appropriate indicators that directly
address whether emissions of these pollutants are in fact being
diluted by the combustion of natural gas.
---------------------------------------------------------------------------
Source 349 is the eighth ranked (out of 11) best performer for the
particulate matter standard. We acknowledge that the ash feed level for
this source is lower than most incinerators equipped with baghouses.
However, particulate matter emissions from sources equipped with
baghouses are not significantly affected by the ash inlet loading to
the baghouse.\46\ This is further supported by the fact that this
source is ranked eighth among the best performers. We conclude source
349 is a best performer not because of its relatively low ash feed
level, but rather because it is equipped with a well designed and
operated baghouse. It is therefore appropriate to include this source
in the MACT analysis.
---------------------------------------------------------------------------
\46\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Vol I: Description of Source Categories,'' September
2005, Section 3.2.2, for further discussion.
---------------------------------------------------------------------------
Comment: Commenters state that source 341 should not be considered
in the MACT analysis because it is a small laboratory waste burner that
processes only 900 lbs/hr of waste. Commenters claim that more than 80
percent of the waste profile is non-hazardous waste.
Response: We approached this comment by asking if it would be
appropriate to create a separate subcategory for source 341. We
conclude it is not necessary to subcategorize hazardous waste
incinerators based on the size of combustion units. This is because the
ranking factors used to identify the relevant best performing sources
are normalized in order to remove the influence that combustion unit
size would otherwise have when identifying best performing sources. See
part 4 section III.D below. Air pollution control system types (a
ranking factor for particulate matter) are generally sized to match the
corresponding volumetric gas flow rate in order to achieve a given
control efficiency. The size of the combustor therefore does not
influence a source's ability to achieve a given control efficiency.
System removal efficiency and hazardous waste feed control MTECs
(ranking factors used by the SRE/Feed methodology as described in part
4 section III.B below) are also not influenced by the size of the
combustor.\47\
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\47\ System removal efficiency is a measure of the amount of the
pollutant that is removed from the flue combustion gas prior to
being emitted and likewise is not influenced by the size of the
combustor because back-end control systems are sized to achieve a
given performance level. Hazardous waste feed control levels are
normalized to remove the influence of combustor size by dividing
each source's mass feed rate by its volumetric gas flowrate.
---------------------------------------------------------------------------
Emission limitations are similarly normalized to remove the
influence of combustion unit size by expressing the standards as
emission concentration limits rather than as mass emission rate limits.
See section III.D. This is illustrated in the following example. Assume
there are two cement kilns side by side with similar designs, the only
difference being one is twice the size of the other, producing twice as
much clinker. They both have identical types of air pollution control
systems (the larger source is equipped with a larger control device
that is appropriately sized to accommodate the larger volumetric gas
flow rates and achieves the same control efficiency as the smaller
control device). If we were to assess performance based on HAP mass
emission rates (e.g., pounds per hour), the smaller source would be the
better performer because its mass emission rates would be half of the
mass emission rate of the larger source, even though they both are
achieving the same back-end control efficiency. Emission
concentrations, on the other hand, are calculated by dividing the HAP
mass emission rate (e.g., pounds per hour) by the volumetric gas
flowrate (e.g., cubic feet per hour). In the above example, both
sources would have identical HAP emission concentrations (the larger
source has twice the mass emission rate, but twice the volumetric gas
flow rate), accurately reflecting their identical control efficiency.
Emission concentrations normalize the size of each source by accounting
for volumetric gas flowate, which is directly tied to the amount of raw
material each source processes (and subsequently the amount of product
that is produced). This is a reason we point out that normalization
eliminates the need to create subcategories based on unit size. See
part four section III.D.
Further, it would be difficult to determine an appropriate minimum
size cutoff in which to base such a subcategorization determination.
Such a subcategorization scheme could also yield nonsensical floor
results, as was the case when we assessed subcategorizing commercial
incinerators and on-site incinerators.\48\
---------------------------------------------------------------------------
\48\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards'', September
2005, Section 4.3.2 for further discussion.
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We have identified source 341 as the best performing source for
particulate matter and low volatile metals. It is the single best
performing source for these standards because it is equipped with a
state-of-the-art baghouse.\49\ This source, which simultaneously feeds
hazardous and nonhazardous wastes, conducted several emission tests
that reflected different modes of operation. The amount of nonhazardous
waste that was processed in the combustion unit varied across test
conditions. We could not ascertain the exact amount of hazardous waste
processed in the test condition that was used in the MACT analysis for
low volatile metals because the test report stated the wastes that were
processed were a mixture of hazardous and nonhazardous wastes, although
we estimate that at least 26% of the waste processed was
nonhazardous.\50\ We note that we are aware of several other
incinerators that processed nonhazardous waste at levels greater than
26 percent during their emission tests. We therefore do not believe
this to be atypical operation that warrants subcategoriztion.
---------------------------------------------------------------------------
\49\ See USEPA, ``Final Technical Support Document for the HWC
MACT Standards, Volume I: Description of Source Categories'',
September 2005, Section 3.2.1, for further discussion.
\50\ See USEPA, ``Final Technical Support Document for the HWC
MACT Standards, Volume I: Description of Source Categories'',
September 2005, Section 2.1 for further discussion.
---------------------------------------------------------------------------
Moreover, the fact that this source was feeding nonhazardous wastes
does not result in atypically low hazardous waste low volatile metal
feed control levels, as evidenced by the relative feed control ranking
for this source of thirteenth among the 26 sources assessed in the MACT
analysis. It also has the highest normalized hazardous waste feed
control level among the best performing sources, and has the fifth best
low volatile metal system removal efficiency among those same 26
sources. We repeat that this source is being identified as the best
performing source primarily because it is equipped with a highly
efficient baghouse, not because it is feeding low levels of HAP metals
attributable to its hazardous waste.
Furthermore, this source is not the lowest emitting source in the
database. There are two sources with similar, but slightly lower low
volatile metal compliance test emissions (one commercial incinerator
and one onsite, non-commercial incinerator). This provides further
evidence that the
[[Page 59432]]
emissions from this source appropriately represent emissions of a
relevant best performing source.
Regarding the particulate matter standard, source 341 does not have
atypically low ash feed rates as compared to other sources equipped
with baghouses. Out of the nine best performing particulate matter
sources for which we have ash feed information, this source ranks
fourth (a ranking of one is indicative of the lowest ash feed rate).
Nonetheless, as previously discussed, particulate matter emissions from
sources equipped with baghouses are not significantly affected by the
ash inlet loading to the baghouse. We note that particulate matter
emissions from the second and third best performing source are not
significantly different from this source, providing further evidence
that this source is representative of the range of emissions exhibited
by other well designed and operating incinerators equipped with
baghouses.\51\
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\51\ Source 341 particulate matter emissions, after accounting
for variability, equated to 0.0015 gr/dscf. The second and third
ranked particulate matter sources emissions, considering
variability, equated to 0.0018 and 0.0023 gr/dscf, respectively.
---------------------------------------------------------------------------
Comment: Commenters state that sources 3018 and 3019 are identified
as best performers for mercury emissions for incinerators. After
evaluating the trial burn plans for these sources, the commenter
believes the data should not be used to calculate the MACT floor
because the spiking rate for mercury was extremely low for a compliance
test. The ranking for feedrate is therefore unrepresentative. The
commenter suggests that these test results should be characterized as
``normal''.
Response: We have verified that the emission tests performed for
sources 3018 and 3019 reflect the upper range of mercury emissions that
are not to be exceeded by these sources, and that their spiked mercury
feed rates were back-calculated from a risk assessment. We therefore
conclude that we properly characterized these emissions as compliance
test emissions data because they reflect the emissions resulting from
the upper bound of hazardous waste mercury feedrates from these
sources.\52\ Consequently, these data are properly included with the
other data used to calculate floor standards for mercury for incinerators.
---------------------------------------------------------------------------
\52\ See February 11, 2005 memo to docket titled ``October 20
Conference Call with Squibb Manufacturing regarding Source #
3018 and 3019''.
---------------------------------------------------------------------------
Comment: Commenters state the trial burn plan for sources 3018 and
3019 describes these units to be of similar design. Thus the difference
in results between these two similar sources is indicative of
additional variability above and beyond the run-to-run variability and
should be assessed if the data are deemed usable at all.
Response: We conclude both of these sources are in fact unique
sources that should be assessed as individual sources for purposes of
the MACT analysis. Although these sources are of similar design, we do
not believe they are identical, in part because: (1) The facility
itself conducted separate emission tests for the two units (rather than
trying to avail itself of the `data in lieu' option, which could save
it the expense of a second compliance test, the obvious inference being
that the source or regulatory official regards the two units as
different); and (2) discussions with facility representatives indicated
these units are similar, but not identical.\53\ As a result, it would
be inappropriate to assess emissions variability by combining the
emissions of these two sources into one test condition given they are
not identical units.
---------------------------------------------------------------------------
\53\ Also see February 11, 2005 memo to docket titled ``October
20 Conference Call with Squibb Manufacturing regarding Source
# 3018 and 3019''.
---------------------------------------------------------------------------
Comment: Commenters state that emissions data from source 327
should not be used to calculate dioxin/furan and mercury floors because
they claim the carbon injection system did not appear to function
properly during the test.
Response: We agree with the commenters. We have determined that
this source encountered problems with its carbon injection system
during the emissions test from which the data were obtained and
subsequently used in EPA's proposed MACT analysis. We have also
verified that this source did not establish operating parameter limits
for the carbon injection system as a result of this test.\54\ We
therefore have excluded this mercury and dioxin data from the MACT
analysis, and have instead used emissions data from an older test
condition to represent this source's emissions.
---------------------------------------------------------------------------
\54\ See July 15, 2005 memo to docket titled ``Telephone
Conversation with Utah DEQ Regarding 2001 Clean Harbor Emission Test.''
---------------------------------------------------------------------------
Comment: Commenters state that the emissions data from source 3006
were based on a miniburn to determine how close the unit was to
achieving the interim MACT standards. The commenter questions whether
these data should be used for purposes of calculating MACT standards.
Response: The fact that a source conducts a voluntary emissions
test (e.g., a miniburn) to determine how close it is operating to
upcoming emission standards does not necessarily lead us to conclude
that the emission data are inappropriate for purposes of calculating
MACT standards. However, since proposal, we have determined that this
source did not measure cadmium emissions during this emissions test. As
a result, we conclude the semivolatile metal emissions data from this
source should not be used in the MACT standard calculation for
semivolatile metals because the data do not represent the source's
combined emissions of lead and cadmium.
II. Affected Sources
A. Area Source Boilers and Hydrochloric Acid Production Furnaces
Comment: Five commenters state that the area sources subject to the
proposed rule are negligible contributors to 112(c)(6) HAP emissions
and should not be subject to major source standards for 112(c)(6) HAP.
Commenters note that requiring compliance with MACT for 112(c)(6) HAP
and RCRA for other toxic pollutants is more complicated and burdensome
for sources than complying only with RCRA. Although an area source can
choose to become regulated as a major source in order to reduce some
RCRA requirements, they would become subject to more onerous emissions
limits under Subpart EEE and the other MACT requirements.
One of these commenters states that subjecting an area source to
major source standards under 112(c)(6) sends a negative message to
industry that EPA does not value emissions reduction and/or chemical
substitution, or other methods used by area sources to achieve that
status. EPA is no longer providing any incentive for sources to take
such difficult yet environmentally beneficial steps to become an area
source. Imposing Title V permitting requirements on an entire facility
that operates as an area source of hazardous air pollutants (HAPs) will
impose an unfair and undue burden on the facility.
Another of these commenters states that section 112(c)(6) requires
in pertinent part that EPA list categories and subcategories of sources
assuring that sources accounting for not less than 90% of the aggregate
emissions of each pollutant (specified in 112(c)(6)) are subject to
standards under Section 112(d)(2) or (d)(4). In 1998, EPA published a
notice identifying the list of source categories accounting for the
section 112(c)(6) HAP emissions and to be regulated under section
112(d) to meet the 90% requirement. (63 FR 17838) At the time, EPA
acknowledged that MACT standards for a number of the source categories
had not yet been promulgated, and stated that when the
[[Page 59433]]
regulations for each of those categories are developed, EPA will
analyze the data specific to those sources and determine, under Section
112(d), in what manner requirements will be established. EPA also
stated that:
``Some area categories may be negligible contributors to the 90%
goal, and as such pose unwarranted burdens for subjecting to
standards. These trivial source categories will be removed from the
listing as they are evaluated since they will not contribute
significantly to the 90% goal.'' (63 FR 17841)
The commenter believes the ``two or fewer'' area source boilers
identified by EPA in the present rulemaking are ``negligible
contributors'' to the 90% goal and therefore, should not be required to
adopt the same MACT emission limitations and requirements as major
sources of the 112(c)(6) pollutants. The commenter believes EPA's
decision to subject area source boilers and hydrochloric acid
production furnaces is incorrect, unsupported by the administrative
record, and therefore arbitrary and capricious.
One commenter states that, if EPA regulates area sources, it should
significantly reduce the administrative burden for area sources by:
exempting them from Title V provisions for Subpart EEE requirements;
exempting them from compliance with the General Provisions of 63
Subpart A; limiting them to a one-time comprehensive performance test;
or limiting other applicable requirements.
Response: We continue to believe that boiler and hydrochloric acid
furnace area sources warrant regulation under the major source MACT
standards for mercury, dioxin/furan, carbon monoxide/hydrocarbons, and
destruction and removal efficiency pursuant to section 112(c)(6).
As discussed at proposal (69 FR at 21212), 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. Five 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, polycyclic organic matter, and
polychlorinated biphenyls.
As discussed below, 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 (and of course
is not prohibited from requiring more than 90 percent of aggregated
emissions to be controlled by 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.
Section 112(c)(6) of the CAA requires EPA to list categories and
subcategories of sources of seven specified pollutants to assure that
sources accounting for not less than 90 percent of the aggregate
emissions of each such pollutant are subject to standards under CAA
section 112(d)(2) or 112(d)(4). In 1998, EPA issued the list of source
categories pursuant to section 112(c)(6), and that list is published at
63 Fed. Reg. 17838, 17849, Table 2 (April 10, 1998).
In the 1998 listing, EPA identified the following three
subcategories of the HWC source category that emit one or more of the
seven section 112(c)(6) pollutants: (1) Hazardous waste incinerators--
(emit mercury, dioxin, furans, polycyclic organic matter (POM) and
polychlorinated biphenyls (PCBs)); (2) Portland cement manufacture:
hazardous waste kilns--(emit mercury, dioxin, furans, and POM); and (3)
lightweight aggregate kilns: hazardous waste kilns--(emit dioxin,
furans, and mercury). These three subcategories are all subject to
today's rule, which is issued pursuant to CAA section 112(d)(2). As
explained below, the HWC NESHAP effectively controls emissions of the
identified section 112(c)(6) pollutants from the identified
subcategories. Accordingly, EPA considers the sources in these three
subcategories as being ``subject to standards'' for purposes of section
112(c)(6).
Specifically, with regard to hazardous waste-burning incinerators,
cement kilns, and lightweight aggregate kilns, EPA is adopting in this
final rule MACT standards for mercury and dioxins/furans. EPA has
already adopted MACT standards for control of POM and PCBs emitted by
these sources in the 1999 rule, which standards were not reopened or
reconsidered in this rulemaking. These standards are the CO/HC
standards, which in combination with the Destruction Removal Efficiency
(DRE) requirement, assure that these sources operate continuously under
good combustion conditions which inhibit formation of POM and PCBs as
combustion by-products, or destroy these HAP if they are present in the
wastes being combusted.\55\ See discussion in Part Four, Sections V.A
and V.B of this preamble.
---------------------------------------------------------------------------
\55\ Courts have repeatedly upheld EPA's authority under CAA
section 112(d) to use a surrogate to regulate hazardous pollutants
if it is reasonable to do so. See, e.g., National Lime, 233 F. 3d at
637 (holding that EPA properly used particulate matter as a
surrogate for HAP metals).
---------------------------------------------------------------------------
The HWC NESHAP also applies to hazardous waste-burning boilers and
hydrochloric acid production furnaces. In particular, for these boilers
and furnaces, this rule addresses emissions of dioxin/furan, mercury,
POM and PCBs either through specific numeric standards for the
identified HAP, or through standards for surrogate pollutants which
control emissions of the identified HAP.
We estimate that approximately 620 pounds of mercury are emitted
annually in aggregate from hazardous waste burning boilers in the
United States.\56\ Also, we estimate that hazardous waste burning
boilers and hydrochloric acid production furnaces emit in aggregate
approximately 2.3 and 0.2 grams TEQ per year of dioxin/furan,
respectively. Controlling emissions of these HAP from area sources
consequently reduces emissions of these HAP through application of MACT
standards. We note that only major source boilers and hydrochloric acid
furnaces are subject to the full suite of subpart EEE emission
standards.\57\ 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. 69 FR at
21212. Consequently, as proposed, area sources in these categories
would be subject only to the MACT standards for mercury, dioxin/furan,
and polycyclic
[[Page 59434]]
organic matter and polychlorinated biphenyls (through the surrogate
standards for carbon monoxide/hydrocarbons and destruction and removal
efficiency) to control the HAP enumerated in 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 Sec. 266.100(b)(3) and the revisions to Sec. Sec. 270.22 and 270.66.
---------------------------------------------------------------------------
\56\ See USEPA ``Technical Support Document for HWC MACT
Standards, Volume V: Emission Estimates and Engineering Costs,''
September, 2005, Section 3.
\57\ We note that as a practical matter, however, the same MACT
standards apply to both major and area source HCl production
furnaces. This is because major sources are subject to the following
standards: CO/HC, DRE, and total chlorine. Because the CO/HC and DRE
standards are surrogates to control dioxin/furan, and the total
chlorine standard is a surrogate to control metal HAP, area sources
are subject to the same standards that address dioxin/furan,
polycyclic organic matter, polychlorinated biphenyls, and mercury.
There is an enforcement difference between the requirements,
however. For area sources, an exceedance of the total chlorine
standard (or failure to ensure that compliance is maintained)
relates to control of mercury only while for a major source, the
same failure relates to control of mercury, other metal HAP, and HCl
and chlorine.
---------------------------------------------------------------------------
Commenters refer to the ``two or fewer'' potential area source
boilers we identified at proposal as ``negligible contributors'' and,
therefore, conclude that these area sources should not be subject to
major source standards for emission of these HAPs. Commenters did not
quantify the amount of emissions from area sources, and did not even
identify how many area sources are at issue. We do not know how many
boilers and hydrochloric acid furnaces are area sources. We apparently
underestimated the number given that four companies commented on the
proposed rule saying that area sources should not be subject to major
source standards for mercury, dioxin/furan, PCBs, and polycyclic
organic matter, and one of those companies indicates it operates
multiple area sources. Consequently, we continue to believe that area
sources in these categories may have the potential to emit more than
negligible levels of these HAP.
We also note that the major source standards are tailored to
minimize the compliance burden for sources that emit low levels of HAP.
Commenters raise concerns about applying the major source standards for
HAP enumerated in section 112(c)(6) to liquid fuel boiler area sources.
The emission standard compliance burden for liquid fuel boilers that
have the potential to emit only low levels of mercury, dioxin/furan,
and polycyclic organic matter is minimal. For example, sources that
emit low levels of mercury because their feedstreams have low levels of
mercury can elect to comply with the mercury emission standard by
documenting that the mercury in feedstreams will not exceed the
standard assuming zero removal by emission control equipment. We note
that 75% of the liquid fuel boilers in our data base, and the two
boilers cited by commenters, do not have emission control devices.
The compliance burden for the major source standards for dioxin/
furan and for the surrogates to control other polycyclic organic
matter--carbon monoxide/hydrocarbons and destruction and removal
efficiency (DRE)--should also be minimal for area source liquid fuel
boilers. The dioxin/furan standard applicable to the 90% of liquid fuel
boilers with wet or no air pollution control equipment is compliance
with the carbon monoxide/hydrocarbon standard and the DRE standard.
Liquid fuel boilers already comply with these same standards under
RCRA. The surrogate standards to control other polycyclic organic
matter are also the carbon monoxide/hydrocarbon and DRE standards.
Finally, we note that the DRE requirement under Subpart EEE is less
burdensome than the DRE requirement under RCRA. Under Subpart EEE, a
source needs to conduct a one-time only DRE test, provided that design
and operation does not change in a manner than could adversely affect
DRE. Under RCRA, the DRE test must be conducted each time the RCRA
permit is renewed.
The incremental compliance burden associated with the other Subpart
EEE major source requirements, such as the operations and maintenance
plan, the startup, shutdown, and malfunction plan, operator training,
and the automatic waste feed cutoff system should also be minimal for
liquid fuel boilers without an emission control device. In addition,
most of the requirements are either identical to or very similar to
requirements under RCRA with which these area sources are already
complying.\58\
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\58\ RCRA, 40 CFR Part 264 requirements that are similar to MACT
requirements include: the general inspection requirements and
personnel training requirements of Subpart B; the preparedness and
prevention requirements of Subpart C, including design and operation
of facility, testing and maintenance of equipment, and access to
communications or alarm system; the contingency plan and emergency
procedures requirements of Subpart D; and the operating requirements
and monitoring and inspection requirements of Subpart O.
---------------------------------------------------------------------------
B. Boilers Eligible for the RCRA Low Risk Waste Exemption
Comment: Several commenters state that EPA should exempt those
boilers that qualify as Low Risk Waste Exemption (LRWE) burners under
the RCRA Boiler and Industrial Furnace Rule at Sec. 266.109 from the
MACT particulate matter and destruction and removal efficiency (DRE)
standards because EPA has not: (1) Made a demonstration that the data
used to provide the exemption to low risk burners under RCRA is no
longer valid; or (2) established in the affirmative that regulating
these units will provide any benefit to human, health and the
environment. Commenters believe that regulating LRWE units under
Subpart EEE is unnecessary and inconsistent with RCRA subtitle C and
more importantly, appears to be controlling LRWE units for control's sake.
Commenters also state that EPA has not properly addressed the
requirements of CAA section 112(n)(7) regarding the inconsistency
between the requirements for Low Risk Waste Exempt (LRWE) units under
RCRA and those of Subpart EEE. The purported purpose of section
112(n)(7) is to allow EPA to avoid imposing additional emission
limitations on a source category subcategory when such limitations
would be unnecessary and duplicative.
In addition, commenters state that the costs associated with this
MACT are much more than improved feed control or better back-end
control. This proposed rule also requires substantial dollar investment
in improved data acquisition, computer controls and recordkeeping
systems, performance testing, training, development of plans, and other
regulatory requirements.
Response: Boilers and hydrochloric acid production furnaces that
currently qualify for the RCRA Sec. 266.109 low risk waste exemption
are not exempt from Subpart EEE under the final rule.
The Administrator does not have the authority under CAA section
112(d) to exempt sources that comply with RCRA Sec. 266.109. Indeed,
there is no necessary connection between the two provisions, since one
is technology-based and the other is risk-based. CAA section 112(d)(2)
requires the Administrator to establish technology-based emission
standards, standards that require the maximum degree of reduction in
emissions that is deemed achievable. Although section 112(d)(4) gives
the Administrator the authority to establish health-based emission
standards in lieu of the MACT standards for pollutants for which a
health threshold has been established, we cannot use that authority to
develop health-based standards for sources that comply with RCRA Sec.
266.109 because those sources emit HAP for which a health threshold has
not been established.
The final rule complies fully with CAA section 112(n)(7) by
coordinating applicability of the RCRA and CAA requirements and
precluding dual requirements. For example, RCRA requirements that are
duplicative of MACT requirements will be removed from the RCRA
operating permit when the permitting authority issues a certification
of compliance after the source submits a Notification of Compliance.
We also note that the MACT standards are tailored to impose
[[Page 59435]]
minimal burden on sources that have low emissions of HAP. The
particulate matter emission standard and associated testing can be
waived (similar to the Sec. 266.109 exemption) for boilers that elect
to document that emissions of total metal HAP do not exceed the limits
provided by Sec. 63.1206(b)(14). Hydrochloric acid production furnaces
are not subject to a particulate matter emission standard.
The compliance burden with the destruction and removal efficiency
(DRE) standard is also minimal given that it is a one-time test,
provided that the source does not change its design or operation in a
manner that would adversely affect DRE. In addition, the compliance
burden for sources with low levels of metals in their feedstreams is
minimal. Sources can document compliance with the metals emission
standards by assuming all metals in the feed are emitted (i.e., by
assuming zero system removal efficiency). Under this procedure, boilers
burning relatively clean wastes are not required to conduct a
performance test to document compliance with the metals emission standards.
Further, we note that the MACT standard to control organic HAP
emissions other than dioxin/furan is the same as the RCRA standard--
demonstrating good combustion conditions by complying with a carbon
monoxide standard of 100 ppmv.
Finally, we note that the ancillary requirements under MACT (e.g.,
personnel training; operating and maintenance plan; startup, shutdown,
and malfunction plan) should not pose substantially higher costs than
similar requirements under RCRA. See response to comment in Section A
above. To the extent that compliance costs increase, we have accounted
for those costs in our estimates of the cost of the final rule.\59\
---------------------------------------------------------------------------
\59\ USEPA ``Technical Support Document for HWC MACT Standards,
Volume V: Emission Estimates and Engineering Costs,'' September, 2005.
---------------------------------------------------------------------------
C. Mobile Incinerators
Comment: A mobile incinerator used as a directly-fired thermal
desorption unit at a Superfund remediation site should not be an
affected source under this rule.
Response: EPA is not determining or changing the applicability of
any hazardous waste burning unit under today's rule. A combustion unit
that treats hazardous waste and meets the definition of incinerator at
40 CFR 260.10 is an affected source under this rule. 40 CFR part 63
also defines a source as any building, structure, facility, or
installation which emits or may emit any air pollutant. A mobile
incinerator at a remediation site meets this definition.
Comment: One commenter states that a subcategory with different
standards must be created for mobile incinerators, or the standards for
incinerators must be calculated using actual emissions data from mobile
units.
Response: EPA did not have any emissions data from mobile
incinerators in the database for the proposed rule. That data base was
developed over many years with ample opportunity for public comment. We
developed a data base for incinerators to support the 1996 proposed
rule (61 FR 17358) and noticed that data base for public comment on
January 7, 1997 (64 FR 52828). We updated that data base in July 2002,
and noticed the revised data base for public comment (67 FR 44452). We
used that revised data base to support the proposed rule. We did not
receive comments providing data for mobile incinerators as a result of
either public notice.
One commenter on the proposed rule provided a summary of emissions
data from one test at a mobile incinerator. The commenter suggested
that the data support its view that its mobile incinerator is unique
and that EPA should consider subcategorizing incinerators according to
mobile incinerators versus other incinerators. We analyzed these data
and conclude that the final standards are readily achievable by this
source. Moreover, as explained elsewhere, EPA's approach to assess the
need for subcategorization is to apply a statistical test to determine
whether the emissions data are statistically different from the
remaining group. Given that owners and operators of mobile incinerators
have not provided emissions data prior to proposal, and that the
commenter provides summarized data for only one mobile incinerator
(which also indicate that the source can achieve the emission standards
in the final rule); we are not compelled to gather additional
information, particularly given our time constraints to promulgate the
final rule under a court-ordered deadline.
Comment: In support of subcategorizing mobile incinerators,
commenters state that mobile thermal treatment systems are
substantially different from hazardous waste incinerators. They are
much smaller in size, firing capacity rate, refractory lining, and
operating temperatures. Most of them treat contaminated soil, so have
very high particulate feedrate loading with high ash content, rapid
kiln rotation rate, and counter-current flow design like cement kilns.
This results in high particulate matter emissions. They operate only
for a short duration at a site (usually less than 6 months), and have
no flexibility with regard to their waste feed.
Response: We recognize that there is variability between various
sources' with regard to size, capacity, operating temperatures etc.,
and so we applied a statistical test to assess the need of
subcategorization, as has been discussed above. The emissions data
provided by the commenter also indicate the source can achieve the
final standards. The soil entrained in desorber off-gases of mobile
incinerators has a relatively large particle size, and is very easy to
capture with conventional particulate control systems (such as a fabric
filter) used by the incinerators.
Comment: Since mobile incinerators are relocated from site to site,
the new source standard should not apply based on the erection date of
the mobile unit.
Response: We are not changing the applicability of a new or
reconstructed source designation in this rulemaking. The relocation
issue is addressed in the definition of ``construction'' in 40 CFR
Section 63.2, which states: ``Construction does not include the removal
of all equipment comprising an affected source from an existing
location and the reinstallation of such equipment at a new location * *
*'' (emphasis added). Therefore, the relocation of an existing Subpart
EEE affected source, such as a mobile incinerator, would not result in
that mobile incinerator becoming a ``new'' source. Keep in mind also
that the relocation exemption only applies to affected sources. If a
mobile incinerator is relocated from an R&D facility (where the unit is
not an affected source per Table 1 to Section 63.1200) to a location
where the mobile incinerator would become an affected source, the
relocation exemption within the definition of ``construction'' would
not apply and the mobile incinerator would be a ``new'' source. Also,
with regard to leased sources, the owner/operator of the facility is
responsible for all affected sources operating at his/her facility
regardless of whether the sources are owned or leased. The owner or
operator should obtain from the leasing company all relevant
information pertaining to the affected source in order to be able to
demonstrate that the affected source is operating in compliance with
the appropriate standards.
III. Floor Approaches
In this section we discuss comments addressing methodologies used
in this rule for determining MACT floors. We address comments relating
both to
[[Page 59436]]
general, overarching issues and to the specific methodologies used in
the rule. Our most important point is that the methodologies EPA
selected reasonably estimate the performance of the best performing
sources by best accounting for these sources' total variability.
A. Variability
1. Authority To Consider Emissions Variability
Comment: Many commenters concur with our approach to account for
emissions variability while several commenters believe that our
approach does not adequately account for emissions variability. See
discussions on separate topics below. One commenter, however, states
that use of variability factors (however derived) is inherently
unlawful and arbitrary and capricious. The commenter notes that,
because floors for existing sources must reflect the ``average''
emission level achieved by the relevant best performing sources, they
cannot reflect any worse levels of performance from the best
performers. Indeed, the argument is that the Clean Air Act already
accounts for variability by requiring EPA to base existing source
floors on the average emission level achieved by the best performing
sources.
The commenter continues by stating that EPA has added variability
factors both to each individual source's performance and to the
collective performance of the alleged best performers, in each case
purporting to find an emission level that the individual or group would
meet ninety-nine times out of 100 future emission tests. Thus, EPA
ignores sources' measured performance in favor of the theoretical worst
performance that might ever be expected from them. By looking to the
best performers' worst performance rather than their average
performance, EPA would set weaker floors than the Clean Air Act allows.
In addition, the commenter notes that EPA's approach to account for
emissions variability is arbitrary and capricious because EPA never
explains why it chose the 99th percentile for its variability
adjustments rather than some other percentile.
Finally, the commenter notes that EPA appears to indicate that its
variability analysis would either be applied to variation between
sources or would affect EPA's statistical analysis of the variation
between sources. The commenter states that any attempt by EPA to add a
variability factor to adjust for intersource variability is unlawful
and arbitrary and capricious.
Response: Our response explains our approach to estimating best
performing sources' variability and addresses the following issues: (1)
Considering the variability in each source's performance is necessary
to identify the best performing sources and their level of performance;
(2) EPA reasonably considered variability in ranking sources to
identify the best performers and in considering the range of best
performing sources' performance over time to identify an emission level
that the average of those sources can achieve; (3) considering
variability at the 99th percentile level is reasonable; (4) considering
intersource variability by pooling run-to-run variability is
appropriate; and (5) compliance test conditions do not fully reflect
all of best performing sources' performance variability.
a. Variability Must Be Considered. Variability in each source's
performance must be considered at the outset in identifying the best
performing sources. This is simply another way of saying that best
performers are those that perform best over time (i.e. day-in, day-
out), a reasonable approach. This approach not only reasonably reflects
the statutory language, but also furthers the ultimate objective of
section 112 which is to reduce risk from exposure to HAP. Since most of
the risk from exposure to emissions from this source category is
associated with chronic exposure to HAP (see Part 1 section VI above),
assessing a source's performance over time by accounting for
variability is reasonable and appropriate.
For similar reasons, variability must be considered in ascertaining
these sources' level of performance. Floors for existing sources must
reflect ``the average emission limitation achieved by the best
performing 12 percent'' of sources, and for new sources, must reflect
``the emission control that is achieved in practice by the best
controlled source.'' Section 112 (d) (3). EPA construes these
requirements as meaning achievable over time, since sources are
required to achieve the standards at all times. This interpretation has
strong support in the case law. See Sierra Club v. EPA, 167 F. 3d 658,
665 (D.C. Cir. 1999), stating that ``EPA would be justified in setting
the floors at a level that is a reasonable estimate of the performance
of the `best controlled similar unit' under the worst reasonably
foreseeable circumstances. It is reasonable to suppose that if an
emissions standard is as stringent as `the emissions control that is
achieved in practice' by a particular unit, then that particular unit
will not violate the standard. This only results if `achieved in
practice' is interpreted to mean `achieved under the worst foreseeable
circumstances'; see also National Lime Ass'n v. EPA, 627 F. 2d 416, 431
n. 46 (D.C. Cir. 1980) (where a statute requires that a standard be
`achievable,' it must be achievable under ``the most adverse
circumstances which can reasonably be expected to recur'');
The court has further indicated that EPA is to account for
variability in assessing sources' performance for purposes of
establishing floors, and stated that this assessment may require EPA to
make reasonable estimates of performance of best performing sources.
CKRC, 255 F. 3d at 865-66; Mossville Environmental Action Now v. EPA,
370 F. 3d 1232, 1242 (D.C. Cir. 2004)(maximum daily variability must be
accounted for when establishing MACT floors).\60\ Indeed, EPA's error
in CKRC was not in estimating best performing sources' variability, but
in using an unreasonable means of doing so. CKRC, 255 F. 3d at 866;
Mossville, 370 F. 3d at 1241.
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\60\ See also Chemical Manufacturers Ass'n v. EPA, 870 F. 2d
177, 228 (5th Cir. 1989) (``The same plant using the same treatment
method to remove the same toxic does not always achieve the same
result. Tests conducted one day may show a different concentration
of the same toxic than are shown by the same test the next day. This
variability may be due to the inherent inaccuracy of analytical
testing, (i.e. `analytical variability,' or to routine fluctuations
in a plant's treatment performance.'')
---------------------------------------------------------------------------
Since the emission standards in today's rule must be met at all
times, the standards need to account for performance variability that
could occur on any single day of these sources' operation (assuming
proper design and operation). See Mossville, 370 F. 3d at 1242
(upholding MACT floor because it was established at a level that took
into account sources' long term performance, not just performance on
individual days). Moreover, since EPA's database consists of single
data points (because there are no continuous emission monitors for HAPs
in stack emissions), EPA must of necessity estimate long-term
performance, including daily maximum performance, from this limited set
of short term data.
b. EPA Reasonably Considered Variability in Ranking Sources to
Identify the Best Performers and in Considering the Range of Best
Performing Sources' Performance Over Time to Identify an Emission Level
that the Average of Those Sources Can Achieve. (1) Selecting Best
Performing Sources. Each of the floor methodologies used in the rule
considers various factors in ranking which sources are the best
performing. For each methodology, we therefore consider the
quantifiable variability of
[[Page 59437]]
the ranking factors in determining which are the best performing
sources. 69 FR at 21230-31. Specifically, we assess run-to-run
variability (normally the only type of variability which we can
quantify) of the factors used under each methodology to rank best
performers. Where SRE/Feed is the ranking methodology, we thus assess
run-to-run variability of hazardous waste HAP feedrate and of system
removal efficiency. Where ranking is based on sources' emissions (the
straight emissions methodology), we assess the run-to-run variability
of emission levels. Where we use the air pollution control device
methodology for ranking, we assess the run-to-run variability of
emissions of the lowest-emitting sources (as we do for straight
emissions) using the best air pollution control devices. For
hydrochloric acid production furnaces, we assess the run-to-run
variability of total chlorine system removal efficiency. Id.\61\
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\61\ These ranking methodologies are discussed later in this
section of the preamble, and in USEPA, ``Technical Support Document
for HWC MACT Standards, Volume III: Selection of MACT Standards,''
September 2005, Section 7.
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To account for run-to-run variability in these ranking factors, we
rank sources by the 99th percentile upper prediction limit (UPL99). The
UPL99 is an estimate of the value that the source would achieve in 99
of 100 future tests if it could replicate the operating conditions of
the compliance test. Id. at 21231.
(2). Assessing the Best Performers' Level of Performance Over Time.
Once we identify the best performing sources, we need to consider their
emissions variability to establish a floor level that the average of
the best performing sources can achieve day-in, day-out. There are two
components of emissions variability that must be considered: run-to-run
variability and test-to-test variability. Run-to-run emissions
variability encompasses variability in individual runs comprising the
compliance tests, and includes uncertainties in correlation of
monitoring parameters and emissions, and imprecision of stack test
methods and laboratory analyses. See 69 FR at 21232.\62\ Test-to-test
emissions variability is the variability that exists between multiple
compliance tests conducted at different times and includes the
variability in control device collection efficiency caused by testing
at different points in the maintenance cycle of the emission control
device \63\, and the variability caused by other uncontrollable factors
such as using a different stack testing crew or different analytical
laboratory, and by different weather conditions (e.g., ambient moisture
and temperature) that may affect measurements.
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\62\ Analytic variability exists, and normally must be accounted
for in establishing technology-based standards based on performance
of the best-performing plants. Chemical Manufacturers Ass'n v. EPA,
870 F. 2d at 230.
\63\ There are myriad factors that affect performance of an
emissions control device. These factors change over time, including
during the maintenance cycle of the device, such that it is
virtually impossible to conduct future compliance tests under
conditions that replicate the performance of the control device. See
USEPA, ``Technical Support Document for HWC MACT Standards, Volume
III: Selection of MACT Standards,'' September 2005, Section 5.3.
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We are able to quantify run-to-run variability. We do so by
applying a 99th percentile modified upper prediction limit to the
averaged emissions of the best performing sources. Id. at 21233 and
Technical Support Document Volume III section 7.2. The modified upper
prediction limit accounts for run-to-run variability of the best
performers by pooling their run variance (i.e., within-test condition
variability).\64\ See Chemical Manufacturer's Ass'n v EPA, 870 F. 2d
177, 228 (5th Cir. 1989) (upholding use of a variability factor
derived, as here, by pooling the performance variability of the best
performing plants). Using this approach, we ensure that the average of
the best performing sources will be able to achieve the floor in 99 of
100 future performance tests, assuming these best performing sources
could replicate their performance when attempting to operate under
identical conditions to those used for the compliance test establishing
the source as best performing. As just noted, we call this value the
modified UPL 99.
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\64\ We note that the Agency used a statistical approach when
proposing the NESHAP for Electric Utility Steam Generating Units.
See memo from William Maxwell, EPA, to Utility MACT Project Files,
entitled, ``Analysis of variability in determining MACT floor for
coal-fired electric utility steam generating units,'' dated Nov. 26,
2003, Docket A-92-55.
---------------------------------------------------------------------------
The only instance in which we are able to quantify test-to-test
variability (as noted above, the other significant component of total
operating variability) is for fabric filters (baghouses) when used to
control emissions of particulate matter. The modified UPL 99 in these
instances reflects not only run-to-run variability, but test-to-test
variability as well. That total variability is expressed by the
Universal Variability Factor which is derived from analyzing long-term
variability in particulate matter emissions for best performing sources
across all of the source categories sources that are equipped with
fabric filters. 69 FR at 21233. See also the discussion below in
Section III.A.2.
Test-to-test variability must be accounted for in other instances
as well, however. It follows that if the performance of most efficient
fabric filters varies over time relative to particulate matter
emissions, then so does their performance relative to the non-mercury
metal HAP emissions. We also believe that particulate matter emissions
variability from sources equipped with back-end controls other than
fabric filters also exists, and is furthermore likely to be higher than
what was calculated for fabric filters because there are more
uncertainties associated with the correlations between operating
parameter limits and control efficiency for these devices.\65\ Again,
it clearly follows that if the performance of these other control
devices varies relative to particulate matter emissions (perhaps even
more than what has already been quantified for fabric filters), then so
does their performance relative to the non-mercury metal HAP emissions.
---------------------------------------------------------------------------
\65\ For example, sources equipped with electrostatic
precipitators generally establish multiple operating limits to best
assure compliance with the emission standard (feed control limits,
power input limits, etc.). There is not an exact correlation between
emission levels and operating levels because there are several
factors that can affect the control efficiency of these air
pollution control systems, such as variations in inlet loads, power
inputs, spark rates, humidity, as well as particle resistivity. See
USEPA, ``Technical Support Document for the HWC MACT Standards,
Volume III: Selection of MACT Standards,'' September 2005, Sections
16 and 17.
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Although we cannot quantify this test-to-test variability, we can
document its existence and its significance. We conducted two parallel
analyses examining all situations where we had multiple test conditions
for the sources ranked as best performing performing (examining
separate pools for best performing sources under both the straight
emissions and SRE/feed ranking methodologies). These analyses showed
that these sources' emissions do in fact vary over time, sometimes
significantly. In many instances sources had poorer system removal
efficiencies and higher emission levels than those in the compliance
test used to identify the source as best performing. We further
projected that in many instances these best performing sources would
not achieve their own UPL 99, the statistically determined prediction
limit which captures 99 out of 100 future three-run test averages for
the source, if they were to operate at the poorer system removal
efficiency of its earlier test and used the federate of its later
(best-performing) compliance test. This is significant because the UPL
99 reflects all of a source's run-to-run
[[Page 59438]]
variability. Failure to meet the UPL 99 thus shows both that further
variability exists, namely test-to-test variability, and that it is a
significant component of total variability. We obtained similar results
when we projected best performing sources' performance based on each of
these sources' overall system removal efficiency obtained by pooling
the removal efficiencies of all of its tests. In many instances,
moreover, these projected levels exceeded floor levels calculated by
using the straight emissions approach, which ranks best performers as
those with the lowest emission levels. This point is discussed further
in Section III.B below. EPA's analysis is set out in detail in chapters
16 and 17 of Volume III of the Technical Support Document.\66\
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\66\ We explain in those sections that these projections assume
that system removal efficiencies are constant across differing HAP
federates and that the sources' historical (poorer) system removal
efficiencies were not the primary result of operating at poorer
``controllable'' conditions relative to the most recent test
condition. These are reasonable assumptions, as explained in section
17. 3 of Volume III of the Technical Support Document, although
these assumptions also create a measure of uncertainty regarding the
emissions projections.
---------------------------------------------------------------------------
EPA's conclusion is that total variability includes both run-to-run
and test-to-test variability, and that both must be accounted for in
determining which are the best performing sources and what are their
levels of performance over time. As explained in the following Sections
B and C, EPA has accordingly adopted floor methodologies which account
for this total variability either quantitatively or qualitatively. The
approach advocated by the commenter simply ignores that variability
exists. Since this approach is contrary to both fact and law, EPA is
not adopting it.
c. Quantifying Run-to-Run Variability at the 99th Percentile Level
Is Reasonable. We selected the 99% prediction limit to ensure a
reasonable level `` namely the 99th percentile--of achievability for
sources designed and operated to achieve emission levels equal to or
better than the average of the best performing sources.\67\ Because of
the randomness of the emission values, there is an associated
probability of the average of the best performing sources, and
similarly designed and operated sources, not passing the performance
test conducted under the same conditions.\68\ At a 99% confidence
level, the average of the best performing sources could expect to
achieve the floor in 99 of 100 future performance tests conducted under
the same conditions as its performance test.. The commenter thus
sharply mischaracterizes a 99% confidence level as the worst
performance of a best performing source.: the level in fact assumes
identical operating conditions as those of the performance test.
---------------------------------------------------------------------------
\67\ Note, again, that the variability we quantify by these
analyses is within-test condition variability only. We cannot
quantify test-to-test variability and thus cannot quantify sources'
total variability.
\68\ See Volume III of the Technical Support Document, Section 7.2 .
---------------------------------------------------------------------------
EPA routinely establishes not-to-exceed standards (daily maximum
values which cannot be exceeded in any compliance test) using the 99%
confidence level. National Wildlife Federation v. EPA, 286 F. 3d 554,
572 (D.C. Cir. 2002).\69\ At a confidence level of only 97% for
example, the average of the best performing sources could expect to
achieve the floor in only 97 of 100 future performance tests.
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\69\ The opinion notes further that percentiles for standards
expressed as long-term average typically use a lower confidence
level (usually 95 %c) due to the opportunity to lower the overall
distribution with multiple measurements. 286 F. 3d at 573. The
standards in this rule are necessarily daily maximum standards
because continuous emissions monitors for HAP do not exist or have
not been demonstrated on all types of Subpart EEE sources.
---------------------------------------------------------------------------
We note that the choice of a confidence level is not a choice
regarding the stringency of the emission standard. Although the
numerical value of the floor increases with the confidence level
selected it only appears to become less stringent. If EPA selected a
lower confidence interval, we would necessarily adjust the standard
downward due to the expectation that a source would not be expected to
achieve the standard for uncontrollable reasons a larger per cent of
the time. We would then have to account in some manner for this
inability to achieve the standard. See Weyerhaeuser v. Costle, 590 F.
2d 1011, 1056-57 (D.C. Cir. 1978) (also upholding standards established
at 99 % confidence level). The governing issue is what level of
confidence should the average of the best performing sources, and
similarly designed and operated sources, have of passing the
performance test demonstrating compliance with the standard. We believe
that the 99% confidence level is a confidence level within the range of
values we could have reasonably selected.\70\
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\70\ See also Chemical Mfrs. Ass'n v. EPA, 870 F. 2d at 229
(99th percentile daily variability factor is reasonable); 227 (``the
choice of statistical methods is committed to the sound discretion
of the Administrator'').
---------------------------------------------------------------------------
d. Considering Intersource Variability by Pooling Run-to-Run
Variability is Appropriate. The commenter believes that any attempt by
EPA to add a variability factor to adjust for intersource variability
is unlawful and arbitrary and capricious. We see no statutory
prohibition in considering intersource run-to-run variability of the
best performing sources (which is all our floor calculation does, by
considering the pooled run-to-run variability of the best performing
sources). Section 112(d)(3) states that MACT floors are to reflect the
``average emission limitation achieved'' but does not specify any
single method of ascertaining an average. Considering the average run-
to-run variability among the group of best performing sources is well
within the language of the provision (and was upheld in CMA, as noted
above; see 870 F. 2d at 228). The commenter's further argument that
`average' can only mean average of emission levels achieved in
performance tests is inconsistent with the holding in Mossville, 370 F.
3d at 1242, that EPA must account for variability in developing MACT
floors and that individual performance tests do not by themselves
account for such variability.
We believe that it is reasonable and necessary to account for
intersource variability of the best performing sources by taking the
pooled average of the best performing sources' run-to-run variability.
This is an aspect of identifying the average performance of those
sources. Emissions data for each best performing source are random in
nature, and this random nature is characterized by a stochastic
distribution. The stochastic distribution is defined by its central
tendency (average value) and the amount of dispersion from the point of
central tendency (variance or standard deviation). Consequently, to
define the performance of the average of the best performing sources,
we must consider the average of the average emissions for the best
performing sources as well as the pooled variance for those sources.
Hence, we must consider intersource variability to identify the floor--
the average performance of the best performing sources.
The commenter further states that EPA's attempt to adjust for
intersource variability is unlawful, arbitrary, and capricious. EPA set
floors at the 99th percentile worst emission level that it believed any
source within the group of best performers could achieve, according to
the commenter. The 99th percentile worst performance that could be
expected from a source within the best performers is, simply put, not
the average performance of the sources in that group, according to the
commenter.
The commenter misunderstands our approach to calculate the floor--
the floor is not the 99th percentile highest emission level that any
best performing source could achieve. The floor for
[[Page 59439]]
existing sources is calculated as the 99th percentile modified upper
prediction limit of the average of the best performing sources. It
represents the average of the best performing sources' emissions levels
plus the pooled within-test condition variance of the best performing
sources. The floor for existing sources is not the highest 99th
percentile upper prediction limit for any best performing source as the
commenter states.
e. Why isn't Total Variability Already Accounted for by Compliance
Test Conditions?
Comment: One commenter states that EPA's use of variability factors
along with worst-case data is unlawful and arbitrary and capricious.
EPA has stated that its use of worst case ``compliance'' data accounts
for variability. EPA admits that compliance data reflect special worst
case conditions created artificially for the purpose of obtaining
lenient permit limits, according to the commenter. EPA provides no
reason whatsoever to believe that a source would continue to operate
under such conditions even one percent of the time. Thus, the commenter
concludes, by applying a 99 percent variability factor to compliance
test data, EPA ensures that the adjusted data do not accurately reflect
the performance of any source. Accordingly, EPA's use of a variability
factor is unlawful.
The commenter also states that, to increase compliance data with
the reality that sources will not be operating under the worst case
conditions except during permit setting tests, the Agency's use of a
variability factor with compliance data is arbitrary and capricious.
Response: All but two standards in the final rule are based on
compliance test data--when sources maximized operating parameters that
affect emissions to reflect variability of those parameters and to
achieve emissions at the upper end of the range of normal operations.
Use of these data is appropriate both because they are data in EPA's
possession for purposes of section 112(d)(3) and because these data
help account for best performing sources' operating variability. CKRC,
255 F. 3d at 867.
The main thrust of the comment is that total variability is
accounted for by the conditions of the performance test, so that making
further adjustments to allow for additional variability is improper.
The commenter believes that the floor should be calculated simply as
the average emissions of the best performing sources and that this
floor would encompass the range of operations of the average of the
best performing sources. We disagree.
The compliance test is designed to mirror the outer end of the
controllable variability occurring in normal operations. These
controllable factors include the amount of HAP fed to a source in
hazardous waste, and controllable operating parameters on pollution
control equipment (such as power input to ESPs, or pressure drop across
wet scrubbers, factors which are reflected in the parametric operating
limits written into the source's permit and which are based on the
results of the compliance testing). However, this is plainly not all of
the variability a source experiences. Other components of run-to-run
variability, including variability relating to measuring (both stack
measurements and measurements at analytic laboratories) are not
reflected, for example. Nor is test-to-test variability reflected,
notably the point in the maintenance cycle that testing is conducted
and the variability associated with those inherently differing test
conditions even though the source attempts to replicate the test
conditions (e.g., measurement variability attributable to use of a
different test crew and analytical laboratory and different weather
conditions such as ambient temperature and moisture). Other changes
that occur over time are due to a wide variety of factors related to
process operation, fossil fuels, raw materials, air pollution control
equipment operation and design, and weather. Sampling and analysis
variations can also occur from test to test (above and beyond those
accounted for when assessing within-test variability) due to
differences in emissions testing equipment, sampling crews, weather,
and analytical laboratories or laboratory technicians.
Thus, there is some need for a standard to account for this
additional variability, and not simply expect for a single performance
test to account for it. The analyses in Sections 16 and 17 of Volume
III of the Technical Support Document confirm these points.
Moreover, the best performing sources (and the average of the best
performers) must be able to replicate the compliance test if they are
to be able to continue operating under their full range of normal
operations. It is thus no answer to say that the best performing
sources could operate under a more restricted set of conditions in
subsequent performance tests and still demonstrate compliance, so that
there is no need to assure that results of initial performance tests
can be replicated. To do so would no longer allow the best performing
sources (and thus the average of the best performing sources) to
operate under their full range of normal operations, and thus
impermissibly would fail to account for their total variability.
As discussed throughout this preamble, emissions variability--run-
to-run and test-to-test variability--is real and must be accounted for
if a best performing source is to be able to replicate the emissions
achieved during the initial compliance test. We consequently conclude
that we must account for variability in establishing floor levels, and
that merely considering the average of compliance test data fails to do
so. We have therefore quantified run-to-run variability using standard
statistical methodologies, and accounted for test-to-test variability
either by quantifying it (in the case of fabric filter particulate
matter removal performance) or accounting for it qualitatively (in the
case of the SRE/feed ranking methodology).
Comment: The commenter notes that if EPA believes that single
performance test results do not accurately capture source's
variability, the solution is to gather more data, not to avoid using a
straight emissions methodology. EPA cannot use this as an excuse for
basing floor levels on a chosen technology rather than the performance
of the best performing sources.
Response: There is no obligation for EPA to gather more performance
data, since the statute indicates that EPA is to base floor levels on
performance of sources ``for which the Administrator has emissions
information.'' Section 112(d)(3)(A); CKRC, 255 F. 3d at 867 (upholding
EPA's decision to use the compliance test data in its possession in
establishing MACT standards). Indeed, the already-tight statutory
deadlines for issuing MACT standards would be even less feasible if EPA
took further time in data gathering. EPA notes further that because
particulate matter continuous emission monitors are not widely used,
even further data gathering would be limited to snapshot, single
performance test results, still leaving the problem of estimating
variability from a limited data set.\71\ See also Sierra Club v. EPA,
167 F. 3d at 662 (``EPA typically has wide latitude in determining the
extent of data-gathering necessary to solve a problem'').
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\71\ Performance tests take an average of 5-8 days to conduct,
and cost approximately from $200,000--$500,000 per test. The
commenter's off-hand suggestion appears to have ignored these realities.
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Thus, EPA has no choice but to assess best performers and their
level of performance on the basis of limited amounts of data per
source. As explained in the previous response to
[[Page 59440]]
comments, EPA has selected a methodology that reasonably do so.
EPA notes further that it has carefully examined those instances
where there are multiple test conditions (usually compliance tests
conducted at different times) for sources ranked as best performing.
This analysis confirms EPA's engineering judgment that total
variability is not fully encompassed in the single test condition
results used to identify these sources as best performing, and that
without taking this additional variability into account, best
performing sources would be unable to achieve the floor standard
reflecting their own performance in those single test conditions.\72\
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\72\ USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards,'', September
2005, Sections 16 and 17.
---------------------------------------------------------------------------
2. Universal Variability Factor for Particulate Emissions Controlled
with a Fabric Filter
Comment: One commenter states that, in calculating the universal
variability factor (UVF) to account for total variability--test-to-test
variability and within-test variability--for sources controlling
particulate matter with a fabric filter, it appears that EPA considered
the variability of sources that are not best performing sources. If so,
EPA has contravened the law.
The commenter also states that EPA's attempt to use a variability
factor derived from an analysis of variability of multiple sources is
unlawful. If EPA considers variability at all, it must consider the
relevant source's variability.
Response: We developed the particulate matter UVF for sources
equipped with a fabric filter using data from best performing sources
only.\73\
---------------------------------------------------------------------------
\73\ USEPA, ``Draft Technical Support Document for HWC MACT
Standards, Volume III: Selection of MACT Standards,'', March 2004, p. 5-4.
---------------------------------------------------------------------------
It is reasonable to aggregate particulate matter emissions data
across source categories for all best performing sources equipped with
a fabric filter because the relationship between standard deviation and
emissions of particulate matter is not expected to be impacted by the
source category type.\74\ Rather, particulate emissions from fabric
filters are a function of seepage (i.e., migration of particles through
the filter cake) and leakage (i.e., particles leaking through pores,
channels, or pinholes formed as the filter cake builds up). The effect
of seepage and leakage on emissions variability should not vary across
source categories.\75\ Put another way, fabric filter particulate
matter reduction is relatively independent of inlet loadings to the
fabric filter. 69 FR 21233. This is confirmed by the fact that there
are no operating parameters that can be readily changed to increase
emissions from fabric filters, id., so control efficiencies reflected
in test conditions from different source types will still accurately
reflect fabric filter control efficiency.
---------------------------------------------------------------------------
\74\ In addition, emissions are not generally affected by
particulate inlet loading.
\75\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards,'' September
2005, Section 5.3.
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3. Test-to-Test Variability
Comment: Several commenters state that EPA seems to have ignored
test-to-test variability resulting from changes that occur over time
such as: normal and natural changes in a wide variety of factors
related to process operation, fuels, raw materials, air pollution
control equipment operation and design, and differences in emissions
testing equipment, sampling crews, weather, analytical laboratories or
laboratory technicians. All these sources of variation are expected in
that they are typical and are not aberrations. In addition, there are
unexpected sources of variability that occur in real-world operations,
which also must be accommodated according to commenters.
Commenters state that using compliance test data and assessing
within-test condition variability (i.e., run variance) do not fully
account for test-to-test variability and thus understates total
variability. Consequently, the average of the best performing sources
may not be able to achieve the same emission level under a MACT
performance test when attempting to operate under the same conditions
as it did during the compliance test EPA used to establish the floor.
Even though sources generally operated at the extreme high end of the
range of normal operations during the compliance tests EPA uses to
establish the standards, the average of the best performing sources
would need to operate under those same compliance test conditions to
establish the same operating envelope--the operating envelope needed to
ensure the source can operate under the full range of normal emissions.
Response: We agree with commenters that we have not quantified
test-to-test variability when establishing the floors for standards
other than particulate matter where a best performing source uses a
fabric filter. We are able to quantify only within-test variability
(i.e., run-to-run variability) for the other floors, which is only one
component of total variability. This is one reason we use the SRE/Feed
approach wherever possible rather than a straight emissions approach to
rank the best performing sources to calculate the floor--the SRE/Feed
ranking approach derives floors that better estimate the levels of best
performing sources' performance. See also discussion in Part Four,
Section III.A, and the discussion below documenting that test-to-test
variability can be substantial.
Comment: One commenter states that EPA should use the universal
variability factor (UVF) that accounts for total variability for
particulate matter controlled with a fabric filter to derive a
correction factor to account for the missing test-to-test variability
component of variability for semivolatile metals and low volatile
metals. The commenter then suggests that the within-test variability
for semivolatile and low volatile metals be adjusted upward by the
correction factor to correct for the missing test-to-test variability
component.
The commenter focused on cement kilns and compared the total
variability imputed from the UVF for the three cement kiln facilities
used to establish the UVF to the within-test variability (i.e., run
variance) for each facility. The commenter determined that, on average
for the three facilities, total variability was a factor of 4.2 higher
than within-test variability. Because semivolatile and low volatile
metals are also controlled with a fabric filter, the commenter
suggested that the total variability of particulate matter could be
used as an estimate of the total variability for semivolatile and low
volatile metals. Thus, the commenter suggested that the within-test
condition variability for semivolatile and low volatile metals be
increased by a factor of 4.2 to account for total variability when
calculating floors.
Response: As stated throughout this preamble, we believe that there
is variability in addition to within-test condition (i.e., run-to-run)
variability that we cannot quantify--that we refer to as test-to-test
variability. We also do not believe this test-to-test variability is
captured by compliance test operating conditions as discussed above,
and thus establishing the floor using emissions data representing the
extreme high end of the range of normal emissions does not account for
test-to-test variability. We disagree, however, with the commenter's
attempts to quantify the remaining test-to-test variability for floors
other than particulate matter
[[Page 59441]]
where all best performing sources are equipped with fabric filters.
We generally agree with the commenter's approach for extracting the
test-to-test component of variability using the UVF curve for
particulate matter controlled with a fabric filter.\76\ The commenter
has documented that for cement kilns, test-to-test variability of
particulate emissions controlled with a fabric filter is on average a
factor of 4.2 higher than within-test variability.
---------------------------------------------------------------------------
\76\ We note, however, that an argument could be made for using
a source or condition-specific correction factor rather than
averaging the correction factors for all sources within a source category.
---------------------------------------------------------------------------
We believe the commenter's suggestion to adopt this correction
factor to semivolatile and low volatile metals is technically flawed
and for several reasons would present statistical difficulties. First,
total variability for semivolatile metals and low volatile metals
controlled with a fabric filter can be different from the total
variability of particulate matter controlled with a fabric filter
because: (1) The test methods are different (i.e., Method 5 for
particulate matter and Method 29 for metals) and thus sample extraction
and analysis methods differ; (2) the factors that affect partitioning
of particulate matter to combustion gas (i.e., entrainment) are
different from the factors that affect semivolatile metal partitioning
to the combustion gas (i.e., metal volatility); and (3) the volatility
of semivolatile metals is affected by chlorine feedrates.
Second, adopting a variability factor applicable to fabric filters
for use on electrostatic precipitators \77\ is problematic because both
test-to-test and within-test variability of these emission control
devices can be vastly different. Factors that affect emissions
variability for sources equipped with a fabric filter include: (1) Bag
wear and tear due to thermal degradation and chemical attack; and (2)
variability in flue gas flowrate. Factors that affect emissions
variability for sources equipped with an electrostatic precipitator are
different (see discussion in Section III.B above) and include:
variations in particle loading and particle size distribution, erosion
of collection plates, and variation in fly ash resistivity due to
changes atmospheric moisture and in sulfur feedrate (e.g. different
type of coal).
---------------------------------------------------------------------------
\77\ We infer that the commenter suggests that we use this
correction factor for semivolatile and low volatile metals
controlled by both electrostatic precipitators and fabric filters
since the majority of cement kilns are equipped with electrostatic
precipitators.
---------------------------------------------------------------------------
Finally, the approach raises several difficult statistical
questions including: (1) What is the appropriate number of runs to use
to identify the degrees of freedom and the t-statistic in the floor
calculations (e.g., should we use the number of runs available for
metals emissions for the source or the number of runs available for
particulate matter emissions from which the correction factor is
derived); and (2) should we use a generic correction factor for all
source categories or calculate source category-specific or source-
specific correction factors.
For these reasons, we believe the approach we use for quantifying
baghouse particulate matter collection variability is not readily
transferable to other types of control devices and other HAP. We
therefore are not applying a quantified correction factor in the final
rule but rather are using a MACT ranking methodology that qualitatively
accounts for total emission variability, notably test-to-test variability.
B. SRE/Feed Methdology
1. Description of the Methodology
As proposed, we are using the System Removal Efficiency (SRE)/Feed
approach to determine the pool of best performing sources for those HAP
whose emissions can be controlled in part by controlling the hazardous
waste feed of the HAP--that is, controlling the amount of HAP in the
hazardous waste fed to the source. These are HAP metals and chlorine.
Our basic approach is to determine the sources in our database with the
lowest hazardous waste feedrate of the HAP in question (semi-volatile
metals, low volatile metals, mercury, or chlorine), and the sources
with the best system removal efficiency for the same HAP. The system
removal efficiency is a measure of the percentage of HAP that is
removed prior to being emitted relative to the amount fed to the unit
from all inputs (hazardous waste, fossil fuels, raw materials, and any
other input). The pool of best performing sources are those with the
best combination of hazardous waste feedrate and system removal
efficiency as determined by our ranking procedure, separate best
performer pools being determined for each HAP in question (SVM, LVM,
mercury, and chlorine), reflecting the variability inherent in each of
these ranking factors (see A.2.a.(1) above). We then use the emission
levels from these sources to calculate the emission level achieved by
the average of the best performing sources, as also explained in the
previous section. This is the MACT floor for the HAP from the source
type. For new sources, we use the same methodology but select the
emission level (adjusted statistically to account for quantifiable
variability) of the source with the best combined ranking. A more
detailed description of the methodology is found in Volume III of the
Technical Support Document, section 7.3.
This methodology provides a reasonable estimate of the best
performing sources and their level of performance for HAP susceptible
to hazardous waste feed control. As required by section 112(d)(2), EPA
has considered measures that reduce the volume of emissions through
process changes, or that prevent pollutant release through capture at
the stack, and assessed how these control measures are used in
combination. Section 112(d)(2)(A), (C) and (E). Hazardous waste feed
control is clearly a process change that reduces HAP emissions; air
pollution control systems collect pollutants at the stack. These are
the best systems and measures for controlling HAP emissions from
hazardous waste combustors. 69 FR at 21226. In considering these
factors, EPA has necessarily considered such factors as design of
different air pollution control devices, waste composition, pollution
control operator training and behavior, and use of pollution control
devices and methodologies in combination. CKRC, 255 F. 3d at 864-65
(noting these as factors, in addition to a particular type of air
pollution control device, that can influence pollution control
performance); 69 FR at 21223 n. 47 (system removal efficiency measures
all internal control mechanisms as well as back-end emission control
device performance).
EPA also believes that this methodology reasonably estimates the
best performing sources' level of performance by accounting for these
sources' total variability, including their performance over time. The
methodology quantifies run-to-run variability. See 69 FR at 21232-33.
It does not quantify test-to-test variability because we are unable to
do so for these pollutants. (See sections A. 2.a.(2) and 3 above.)
Although all variability must be accounted for when calculating floors,
the only definitive way to accurately quantify this test-to-test
emissions variability is through evaluation of long-term continuous
emissions monitoring data, which do not presently exist. We believe,
however, that SRE/Feed methodology provides some margin for estimating
this additional, non-quantifiable variability. This is illustrated in
the technical support document (volume III section 17), which clearly
shows that the straight emissions approach underestimates (indeed,
fails to account
[[Page 59442]]
for) lower emitting sources' long-term emissions variability. These
lower emitting sources that would otherwise not meet the floor levels
on individual days under the straight emission approach would be able
(or otherwise are more capable) to do so under the SRE/feed approach.
EPA further believes that the SRE/Feed methodology appropriately
accounts for design variability that exists across sources for
categories, like those here, which consist of a diverse and
heterogeneous mixture of sources. This is especially true of
incinerators and boilers, for which there are smaller on-site units
that are located at widely varying industrial sectors that essentially
combust single, or multiple wastestreams that are specific to their
industrial process, and off-site commercial units dealing with many
different wastes of different origins and HAP metal and chlorine
composition. EPA believes that these variations are best encompassed in
the SRE/Feed approach, rather than with a subcategorization scheme that
could result in anomalous floor levels because there are fewer sources
in each source subcategory from which to assess relative
performance.\78\ See Mossville, 370 F. 3d at 1240 (upholding floor
methodology involving reasonable estimation, rather than use of
emissions data, when sources in the category have heterogeneous
emission characteristics due to highly variable HAP concentrations in
feedstocks).
---------------------------------------------------------------------------
\78\ At proposal, we conducted a technical analysis to determine
potential subcategorization options. We then conducted an analysis
to determine if these different types of sources exhibited
statistically different emissions. Although EPA in the end
determined that these source categories should not be subcategorized
further, this decision was based in part because the SRE/Feed
methodology better accounts for the range of emissions from the best
performing sources for these diverse combustion types. See USEPA,
``Technical Support Document for the HWC MACT Standards, Volume III:
Selection of MACT Standards,'' September 2005, Section 4, for an
explanation of the subcategorization assessment, which includes
examples of anomalous floor results for certain subcategorization
approaches.
---------------------------------------------------------------------------
Use of the SRE/Feed approach also avoids basing the floor standards
on a combination of the lowest emitting low feeding sources and the
lowest emitting high feeding sources. For example, the five lowest
emitting incinerators for semivolatile metals that would comprise the
MACT pool using a straight emissions methodology include three sources
that are the first, second, and fourth lowest feeding sources among all
the incinerators.\79\ The other two best performing incinerators have
the first and second best system removal efficiencies (and the highest
two metal feedrates). It is noteworthy that the highest feed control
level among these best performing sources is over three orders of
magnitude higher than the feed control level of the lowest feeding best
performing source.\80\ Establishing limits dominated by both superior
feed control sources and back-end controlled sources would result in
floor levels that are not reflective of the range of emissions
exhibited by either low feeding sources or high feeding sources and
would more resemble new source standards for both of these different
types of combustors. Such floors could lead to situations, for example,
where commercial sources could find it impracticable to achieve the
standards without reducing the overall scope of their operations (since
the standard could operate as a direct constraint on the amount of
hazardous waste that could be fed to the device, in effect depriving a
combustion source of its raw material). Similarly, low feeding sources
that cannot achieve this floor level may be required to add expensive
back-end control equipment that would result in minimal emission
reductions, likely forcing the smaller on-site source to cease
hazardous waste treatment operations and to instead send the waste to a
commercial treatment unit.
---------------------------------------------------------------------------
\79\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards,'' September
2005, Appendix C, Table ``E--INC--SVMCT'' and, to determine relative
feed control and SRE rankings for these sources, Appendix E Table
``SF--INC--SVMCT''.
\80\ Source 340 had a semivolatile metal feed control MTEC of
892 [mu]g/dscm, whereas source 327 had a semivolatile metal feed
control MTEC of 3,080,571 [mu]g/dscm.
---------------------------------------------------------------------------
The inappropriateness of a straight emissions-based approach for
feed controlled pollutants for commercial hazardous waste combustors is
further highlighted by the fact that several commercial hazardous waste
combustors that are achieving the design level of the particulate
matter standard are not achieving the semivolatile and/or low volatile
metals straight emissions based design level, and, in some instances,
floor level.\81\ This provides further evidence that low feeding
sources are in fact biasing some of the straight emissions-based floors
to the extent that even the sources with the most efficient back-end
control devices would be incapable of achieving the emission standards
calculated on a straight emission basis.
---------------------------------------------------------------------------
\81\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards,'' September
2005, Section 17.4
---------------------------------------------------------------------------
These results are inconsistent with the intent of the section 112
(d) (see 2 Legislative History at 3352 (House Report) stating that MACT
is not intended to drive sources out of business). Standards that could
force commercial sources to reduce the overall scope of their
operations are also inconsistent with requirements and objectives of
the Resource Conservation and Recovery Act to require treatment of
hazardous wastes before the wastes can be land disposed, and to
encourage hazardous waste treatment. RCRA sections 3004 (d), (e), (g)
and 1003 (a) (6); see also section 112 (n) (7) of the CAA, stating that
section 112 (d) MACT standards are to be consistent with RCRA subtitle
C emission standards for the same sources to the maximum extent
practicable (consistent with the requirements of section 112 (d));
moreover, EPA doubts that a standard which precludes effective
treatment mandated by a sister environmental statute must be viewed as
a type of best performance under section 112 (d). The SRE/Feed
methodology avoids this result by always considering hazardous waste
feed control in combination with system removal efficiency and
according equal weight to both means of control in the ranking process.
It is also important to emphasize what the SRE/Feed methodology
does not evaluate: Feed control of HAP in fossil fuel or raw material
inputs to these devices. Emission reduction of these HAP are
controllable by back-end pollution control devices which remove a given
percentage of pollutants irrespective of their origin and is assured by
the system removal efficiency portion of the methodology, as well as
through the particulate matter standard (see section IV.A below). Feed
control of these inputs is not a feasible means of control, however.
HAP content in raw materials and fossil fuel can be highly variable,
and so cannot even be replicated by a single source. Raw material and
fossil fuel sources are also normally proprietary, so other sources
would not have access to raw material and fossil fuel available (in its
performance test) to a source with low HAP fossil fuel and raw material
inputs. Such sources would thus be unable to duplicate these results.
Moreover, there are no commercial-scale pretreatment processes
available for removing or reducing HAP content in raw materials or
fossil fuels to these units. See technical support document volume III
section 17.5 and 25; see also 69 FR at 21224 and n. 48.
2. Why Aren't the Lowest Emitters the Best Performers?
Some commenters nonetheless argue that best performing sources can
only mean sources with the lowest HAP
[[Page 59443]]
emissions, and that the SRE/Feed methodology is therefore flawed
because it does not invariably select lowest emitters as best
performers.\82\ The statute does not compel this result. There is no
language stating that lowest emitting sources are by definition the
best performers. The floor for existing sources is to be based on the
average emission limitation achieved by the ``best performing'' 12 per
cent of sources. Section 112(d)(3)(A). This language does not specify
how ``best performing'' is to be determined: by means of emission
level, emission control efficiency, measured over what period of time,
etc. See Sierra Club v. EPA, 167 F. 3d at 661 (language of floor
requirement for existing sources ``on its own says nothing about how
the performance of the best units is to be calculated''). Put another
way, this language does not answer the question of which source is the
better performing: one that emits 100 units of HAP but also feeds 100
units of that HAP, or one that emits 101 units of the HAP but feeds
10,000 units. See 69 FR at 21223. Moreover, new source floors are to be
based on the performance of the ``best controlled'' similar source
achieved in practice. Section 112(d)(3). ``Best controlled'' can
naturally be read to refer to some means of control such as system
removal efficiency as well as to emission level.
---------------------------------------------------------------------------
\82\ In fact, many of the sources identified as best performing
under the SRE/Feed methodology are also the lowest emitting,
although this is not invariably the case.
---------------------------------------------------------------------------
Use of a straight emissions approach to identify floor levels can
lead to arbitrary results. Most important, as explained above, it leads
to standards which cannot be achieved consistently even by the best
performing sources because operating variability is not accounted for.
This is shown in section 17 of volume III of the technical support
document. These analyses show that (a) emissions from these sources do
in fact vary from test-to-test, and that no two snapshot emission test
results are identical; (b) our statistical approach that quantifies
within test, run-to-run variability underestimates the best performing
sources' long term, test-to-test variability; \83\ (c) best performing
sources under the straight emissions approach advocated by the
commenter (i.e. the lowest emitting sources) had other test conditions
that did not achieve straight emission floor levels; (d) best
performing sources under the straight emissions approach are projected,
based on two separate analyses using reasonable assumptions, not to
achieve the straight emissions floor standard based on these sources'
demonstrated variations in system removal efficiencies over time (i.e.,
from test-to-test); and (e) SRE/feed methodology yields floor levels
(i.e. the floor standards in the rule) that better estimate the
emission levels reflecting the performance over time of the best
performing sources. See Mossville, 370 F. 3d at 1242 (floor standard is
reasonable because it accommodated best performing source's highest
level of performance (i.e. its total variability), even though the
level of the standard was higher than any individual measurement from
that source).
---------------------------------------------------------------------------
\83\ Best performing sources pursuant to the straight emissions
methodology are projected to be unable to achieve the levl of their
of their performance test emissions even after they are adjusted
upward to account for run-to-run variability.
---------------------------------------------------------------------------
As noted earlier, the straight emissions methodology can also limit
operation of commercial units because the standard reflects a level of
hazardous waste feed control which could force commercial units to burn
less hazardous waste because such standards more resemble new source
standards. The straight emissions methodology also arbitrarily reflects
HAP levels in raw materials and fossil fuels, an infeasible means of
control for any source.
Another arbitrary, and indeed impermissible, result of the straight
emissions methodology is that in some instances (noted in responses
below) the methodology results in standards which would force sources
identified as best performing to install upgraded air pollution control
equipment. This result undermines section 112 (d) (2) of the statute,
by imposing what amounts to a beyond the floor standard without
consideration of the beyond the floor factors: the cost of achieving
those reductions, as well as energy and nonair environmental impacts.
Comment: The commenter states that because MACT floors must reflect
the ``actual performance'' of the relevant best performing hazardous
waste combusters, this means that the lowest emitters must be the best
performers. The commenter cites CKRC v. EPA, 255 F. 3d at 862 and other
cases in support.
Response: As explained in the introduction above, the statute does
not specify that lowest emitters are invariably best performers. Nor
does the caselaw cited by the commenter support this position. The D.C.
Circuit has held repeatedly that EPA may determine which sources are
best performing and may ``reasonably estimate'' the performance of the
top 12 percent of these sources by means other than use of actual data.
Mossville, 370 F. 3d at 1240-41 (collecting cases). In Mossville,
sources had varying levels of vinyl chloride emissions due to varying
concentrations of vinyl chloride in their feedstock. Individual
measurements consequently did not adequately represent these sources'
performance over time. Not-to-exceed permit limits thus reasonably
estimated sources' performance, corroboration being that individual
sources with the lowest long-term average performance occasionally came
close to exceeding those permit limits. Id. at 1241-42. The facts are
similar here, since our examination of best performing sources with
multiple test conditions likewise shows instances where these sources
would be unable to meet floors established based solely on lowest
emissions (including their own). As here, EPA was not compelled to base
the floor levels on the lowest measured emission levels.
Comment: The same commenter maintains that it is clear from the
caselaw that MACT floors must reflect the relevant best performing
sources' ``actual performance'', and that this must refer to the
emissions level it achieves.
Response: As just stated, the D.C. Circuit has repeatedly stated
that EPA may make reasonable estimates of sources' performance in
assessing both which sources are best performing and the level of their
performance. The court has further indicated that EPA is to account for
variability in assessing sources' performance for purposes of
establishing floors, and this assessment may require that EPA make
reasonable estimates of performance of best performing sources. CKRC,
255 F. 3d at 865-66; Mossville, 370 F. 3d at 1241-42. See discussion in
A.1.a above.
Comment: The commenter generally maintains that EPA's floor
approaches consider only the performance of back-end pollution control
technology and so fail to capture other means of HAP emission control
that otherwise would be captured if EPA were to assess performance
based on the emission levels each source achieved.
Response: EPA agrees that factors other than end-of-stack pollution
control can affect metal HAP and chlorine emissions. This is why EPA
assesses performance for these HAP by considering combinations of
system removal efficiency (which measures every element in a control
system resulting in HAP reduction, not limited to efficiency of a
control device), and hazardous waste HAP feed control. Standards for
dioxins and other organic HAP (which have no hazardous waste feed
control component) likewise assess every element of control.
[[Page 59444]]
EPA also accounts for the variability of HAP levels in the
(essential) use of raw materials and fossil fuels by assessing
performance of back-end control but not evaluating fuel/raw material
substitution, which, as discussed later in the response to comments
section, are infeasible means of control. Mossville, 370 F. 3d at 1241-
42, is instructive on this point. The court held that the constant
change in raw materials justified EPA's use of a regulatory limit to
estimate a floor level. The reasonableness of this level was confirmed
by showing that the highest individual data point of a best performing
source was nearly at the level of the regulatory limit. Under the
commenter's approach, the court would have had no choice but to hold
that the level the source achieved in a single test result using
`clean' raw materials--i.e. the `level achieved' in the commenter's
language--dictated the floor level.
See part four, section III.C for EPA's response to this comment as
it relates to the methodologies for the particulate matter standard and
total chlorine standard for hydrochloric acid production furnaces.
Comment: The commenter notes that the SRE/Feed methodology does not
account for all HAP emissions, failing to account for metal and
chlorine feedrates in raw materials and fossil fuels.
Response: The methodology does not assess the effect of feed
``control'' of HAP levels in raw materials or fossil fuels which may be
inputs to the combustion units. This is because such control may not be
replicable by an individual source, or duplicable by any other source.
See 69 FR at 21224 and n. 48; Sierra Club v. EPA, 353 F. 3d 976, 988
(``substitution of cleaner ore stocks was not * * * a feasible basis on
which to set emission standards. Metallic impurity levels are variable
and unpredictable both from mine to mine and within specific ore
deposits, thereby precluding ore-switching as a predictable and
consistent control strategy'').\84\ EPA's methodology does account for
HAP control of all inputs by assessing system removal efficiency, which
measures reductions of HAPs in all inputs (including fossil fuel and
raw materials) to a hazardous waste combustion unit. Further,
nonmercury metal HAP emissions attributable to raw materials and fossil
fuels are effectively controlled with the particulate matter standard,
a standard that is based on the sources with best back-end control
devices. The only element which is not controlled is what cannot be:
HAP levels in feeds for which fuel or raw material switching is simply
not an available option.
---------------------------------------------------------------------------
\84\ Although this language arose in the context of a potential
beyond-the-floor standard, EPA believes that the principle stated is
generally applicable. MACT standards, after all, are technology-
based, and if there is no technology (i.e. no avaialble means) to
achieve a standard--i.e. for a soruce to achieve a standard whenever
it is tested (as the rules require)--then the standard is not an
achieveable one.
---------------------------------------------------------------------------
Comment: The commenter further maintains, however, that the means
by which sources may be achieving levels of performance are legally
irrelevant (citing National Lime Ass'n v. EPA, 233 F. 3d 625 , 634 and
640 (D.C. Cir. 2000)). The fact that sources with ``cleaner'' raw
material and fossil fuel inputs may not intend to have resulting lower
HAP emissions is therefore without legal bearing.
Response: The issue here is not one of intent. The Court, in
National Lime, rejected the argument that sources' lack of intent to
control a HAP did not preclude EPA from establishing a section 112(d)
standard for that HAP. See 233 F. 3d at 640, rejecting the argument
that HAP metal control achieved by use of back-end control devices
(baghouses) could not be assessed by EPA because the sources used the
back-end control devices to control emissions of particulate matter.
The case did not consider the facts present here, where the issue is
not a source's intent, but rather a means of control which involves
happenstance (composition of HAP in raw materials and fossil fuel used
the day the test was conducted) and so is neither replicable nor
duplicable.
National Lime also held that EPA must establish a section 112(d)
emission standard for every HAP emitted by a major source. 233 F. 3d at
634. EPA is establishing emission standards for all HAP emitted by
these sources. In establishing these standards, EPA is not evaluating
emission reductions attributable to the type of fossil fuel and raw
material used in the performance tests, because this is not a
``feasible basis on which to set emission standards.'' Sierra Club, 353
F. 3d at 988.
EPA thus does not agree with this comment because the issue is not
a source's intent but rather whether or not to assess emission
reductions from individual test results which reflect an infeasible
means of control.
Comment: The commenter maintains, however, that even if individual
sources (including those in the pool of best performing sources) cannot
reduce HAP concentrations in raw materials and fossil fuels, they may
achieve the same reductions by adding back-end pollution control.
Nothing in section 112(d)(3) says that sources have to use the means of
achieving a level of performance that other best performing sources used.
Response: The thrust of this comment is essentially to
impermissibly bypass the beyond-the-floor factors set out in section
112(d)(2) under the guise of adopting a floor standard. Suppose that
EPA were to adopt a floor standard dominated by emission levels
reflecting HAP concentrations present in a few sources' raw materials
and fossil fuels during their test conditions. Suppose further that
some sources have to upgrade their back-end control equipment to
operate at efficiencies better than the average level demonstrated by
the best performing sources, because test results based on fossil fuel
and raw material levels are neither replicable nor duplicable. In this
situation, EPA believes that it would have improperly adopted a beyond-
the-floor standard because EPA would have failed to consider the
beyond-the-floor factors (cost, energy, and nonair environmental
impacts) set out in section 112(d)(2).\85\
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\85\ Analysis of the levels of HAP in raw matrial and
nonhazardous waste fuels suggests that this is a realistic outcome.
Our analysis shows that emissions attributable to raw material and
fossil fuel can be significant relative to the level of the straight
emissions-based floor design level and floor (the methodology
advocated by the commenter), and therefore could inappropriately
impact a sournce's ability to comply with such a floor standard. See
USEPA, ``Technical Support Document for the HWC MACT Standards,
Volume III: Selection of MACT Standards,'' September 2005, Section 17.6.
---------------------------------------------------------------------------
Comment: EPA has not substantiated its claim that sources cannot
switch fossil fuels or raw materials.
Response: At proposal we evaluated fuel switching and raw material
substitution as beyond-the-floor technologies for cement kilns and
lightweight aggregate kilns and stated these technologies would not be
cost effective.\86\ We also discussed why fuel switching is not an
appropriate floor control technology for solid fuel-fired boilers. 69
FR at 21273. Upon further evaluation, we again conclude that fuel
switching and raw material substitution are not floor control
technologies and are not cost effective beyond-the-floor technologies
for cement kilns, lightweight aggregate kilns, and solid fuel-fired
boilers.\87\
---------------------------------------------------------------------------
\86\ See, for example, 69 FR at 21252, where we discuss the use
of fuel-switching or raw material substitution as a possible beyond-
the-floor control for mercury at cement kilns.
\87\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards, September 2005,
Sections 11 and 25, for further discussion.
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Comment: EPA has failed to document the basis for its SRE ranking.
[[Page 59445]]
Specifically, EPA has not stated how it measured sources' SREs, or how
it knows those rankings are accurate.
Response: System removal efficiency is a parameter that is included
in our database that is calculated by the following formula:
[GRAPHIC]
[TIFF OMITTED]
TR12OC05.000
The HAP feedrate and emission data are components of the database
that were extracted from emission test reports for each source. We use
system removal efficiency for each relevant pollutant or pollutant
group (e.g., semivolatile metals, low volatile metals, mercury, total
chlorine) whenever the data allows us to calculate a reliable system
removal efficiency. For example, we generally do not use system removal
efficiencies that are based on normal emissions data because of the
concern that normal feed data are too sensitive to sampling and
measurement error. See 69 FR at 21224.\88\
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\88\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume II: Database,'' September 2005, Section 2, for
further discussion on system removal efficiencies, which includes
sample calculations and references to the database that contain the
calculated system removal efficiencies for each source and each HAP
or HAP group.
---------------------------------------------------------------------------
The system removal efficiencies used in our ranking process are
reliable and accurate because the feed and emissions data originate
from compliance tests that demonstrate compliance with existing
emission standards (primarily RCRA requirements). As such, the data are
considered to have excellent accuracy and quality. RCRA trial burn and
certification of compliance reports are typically reviewed in detail by
the permitting authority. The compliance tests and test reports
generally contain the use of various quality assurance procedures,
including laboratory, method, and field blanks, spikes, and surrogate
samples, all of which are designed to minimize sampling and analytical
inaccuracies. EPA also noticed the data base for this rule for multiple
rounds of comment and has made numerous changes in response to comment
to assure accuracy of the underlying data. Thus, EPA concludes the
calculated system removal efficiencies used in the ranking process are
both reliable and accurate.
Comment: EPA's approach with regard to use of stack data is
internally contradictory. EPA uses stack data in establishing floors,
but does not use stack data to determine which performers are best. EPA
has failed to explain this contradiction.
Response: Emission levels are used to calculate system removal
efficiencies in order to assess each source's relative back-end control
efficiency. Also, as explained in the introduction to this comment
response section, the SRE/Feed methodology uses the stack emission
levels of the sources using the best combinations of hazardous waste
feed control and system-wide air pollution control (expressed as HAP
percent removal over the entire system) to calculate the floors. The
data are adjusted statistically to account for quantifiable forms of
variability (run-to-run variability). This methodology reasonably
selects best performing sources (for HAP amenable to these means of
control), and reasonably estimates these sources' performance over
time. As further stated in section B.2 above, using a straight
emissions approach to identify best performers and their level of
performance can lead to standards for these HAP that do not fully
account for variability (including variability resulting from varying
and/or uncontrollable amounts of HAP in raw materials and fossil fuels)
and could force installation of de facto beyond-the-floor controls
without consideration of the section 112(d)(2) beyond-the-floor factors.
EPA thus does not see the contradiction expressed by the commenter.
Use of the straight emissions approach as advocated by the commenter
would lead to standards that do not reasonably estimate sources'
performance and which could not be achieved even by the best performers
with individual test conditions below the average of the 12 percent of
best performing sources. These problems would be compounded many-fold
if the data were not normalized and adjusted to at least account for
quantifiable variability, steps the commenter also opposes. EPA's use
of emissions data (suitably adjusted) after identifying best performers
through the ranking methodology avoids these problems and reasonably
estimates best performers' level of performance.
Comment: The commenter rejects EPA's finding (69 FR at 21226) that
individual test results in the data base do not fully express the best
performing sources' performance. The commenter gives a number of
reasons for its criticisms, which we answer in the following sequence
of comments listed a though f.
a. Comment: The commenter states that EPA claims emission levels do
not fully reflect variability in part because they are sometimes based
on tests where the source was feeding low levels of HAP during the
test. The commenter claims this is inconsistent with the fact that EPA
preferentially uses worst-case emissions obtained from tests where the
sources spiked their feedstreams with metals, and that the mere
possibility that these emissions do not reflect test data from
conditions where variability was not maximized does not mean those data
fail to represent a source's actual performance. The commenter also
states that ``EPA's apparent suggestion that the best performing
sources could not replicate the average performance of the sources with
the lowest emissions is unsubstantiated and unexplained. Assuming that
EPA accurately assesses a source's actual performance, the source can
replicate that performance.''
Response: HAPs in raw materials and fossil fuels contribute to a
source's emissions. EPA has concerns that a straight emissions approach
to setting floors may not be replicable by the best performing sources
nor duplicable by other non-best performing sources because of varying
concentration levels of HAP in raw material and nonhazardous waste
fuels. The best performing sources operated under compliance test
conditions as the commenter suggests. However, raw material and
nonhazardous fuel HAP concentrations for the best performing sources
will change over time, perhaps due to a different source of fuel or raw
material quarry location, which could affect their ability to achieve
the floor level that was based on emissions obtained while processing
different fossil fuel or raw materials. EPA takes sharp issue with the
commenter's statement that a single performance test result is
automatically replicable so long as it is measured properly in the
first instance. This statement is incorrect even disregarding HAP
contributions in raw materials and fossil fuels since, as noted
previously in section A.2.e, there are many other sources of
variability
[[Page 59446]]
which will influence sources' performance over time (i.e., in
subsequent performance tests).
A straight emissions approach for establishing semivolatile and low
volatile metal floors may result in instances where the best performing
sources would not be capable of achieving the standards if their raw
material and nonhazardous waste fuel HAP levels change over time. For
each cement kiln and lightweight aggregate kiln, we estimated the
emissions attributable to these raw materials and fossil fuels assuming
each source was operating with hazardous waste HAP feed and back-end
control levels equivalent to the average of the best performing sources
(the difference in emissions across sources only being the result of
the differing HAP levels in the nonhazardous waste feeds). The analysis
shows that emissions attributable to these nonhazarous waste
feedstreams (raw materials and fossil fuels) varies across sources, and
can be significant relative to the level of the straight emissions-
based floor design level and floor, and therefore could inappropriately
impact a source's ability to comply with the floor standard.\89\
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\89\ See USEPA, ``Final Technical Support Document for the HWC
MACT Standards, Volume III: Selection of MACT Standards,'' September
2005, Section 17.6. .
---------------------------------------------------------------------------
b. Comment: The commenter states that EPA must consider
contributions to emissions from raw materials and fossil fuels, that it
is irrelevant if sources from outside the pool of best performing
sources can duplicate emission levels reflecting ``cleaner'' raw
materials and fossil fuels used by the best performing sources, and
that sources unable to obtain such ``cleaner'' inputs may always
upgrade other parts of their systems to achieve that level of performance.
Response: As previously discussed, EPA's methodology does account
for HAP control of all inputs by assessing system removal efficiency,
which measures reductions of HAPs from all inputs. Further, nonmercury
metal HAP emissions attributable to raw materials and fossil fuels are
effectively controlled with the particulate matter standard, a standard
that is based on the sources with lowest emissions from best back-end
control devices. We are not basing any standards on performance of
sources not ranked as among the best performing.
c. Comment: The commenter disputes EPA's conclusions that failure
of sources to meet all of the standards based on a straight emissions
methodology at once shows that the methodology is flawed. The standards
are not mutually dependent, so the fact that they are not achieved
simultaneously is irrelevant. There is no reason a best performer for
one HAP should be a best performer for other HAP.
Response: EPA agrees with this comment. On reflection, EPA believes
that because all our standards are not technically interdependent
(i.e., implementation of one emission control technology does not
prevent the source from implementing another control technology), the
fact that sources are not achieving all the standards simultaneously
does not indicate a flaw in a straight emissions approach. See Chemical
Manufacturers Ass'n, 870 F. 2d at 239 (best performing sources can be
determined on a pollutant-by-pollutant basis so that different plants
can be best performers for different pollutants).
d. Comment: Several commenters took the opposite position that EPA
must assure that all existing source standards must be achievable by at
least 6 percent of the sources, and that all new source standards must
be achievable by at least one existing source.
Response: As discussed above, we are not obligated to establish a
suite of floors that are simultaneously achievable by at least six
percent of the sources because the standards are not technically
interdependent. Nonetheless, the SRE/Feed methodology does result in
existing floor levels (when combined with the other floor levels for
sources in the source category) that are simultaneously achievable by
at least six percent of the sources (or, for source categories that
have fewer than 30 sources, by at least two or three sources).\90\
However, for the new source standards, three of the source categories
do not include any sources that are simultaneously achieving all the
standards (incinerators, cement kilns, and lightweight aggregate
kilns). Again, similar to existing sources, EPA is not obligated to
establish a suite of new source floors that are simultaneously
achievable by at least one existing source because these standards are
not technically interdependent. We conclude that a new source can be
designed (from a back-end control perspective) to achieve all the new
source standards.\91\
---------------------------------------------------------------------------
\90\ These achievability analyses did not account for the
additional test-to-test variability that we cannot quantify.
\91\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume V: Emission Estimates and Engineering Costs,''
September 2005, Section 4.2.3 for a discussion that explains how
such a new source could be designed to achieve the new source standards.
---------------------------------------------------------------------------
e. Comment: The commenter criticizes EPA's discussion at 69 FR
21227-228 indicating that both hazardous waste feed control and back-
end pollution control are superior means of HAP emission control and
treatment standards should be structured to allow either method to be
the dominant control mechanism.
Response: EPA is not relying on this part of the proposed preamble
discussion as justification for the final rule, with the one exception
noted in the response to the following comment.
f. Comment: Considerations of proper waste disposal policy are not
relevant to MACT floor determinations. In any case, the possibility
that some commercial waste combustors may upgrade their back-end
pollution control systems to meet standards reflecting low hazardous
waste HAP feedrates, or divert wastes to better-controlled units, is
positive, not negative.
Response: As discussed in section B.1 above, there are instances
where standards derived by using a straight emissions approach are
based on a combination of lowest emitting low feeding sources and
lowest emitting higher feeding sources. Resulting floor standards would
thus reflect these low hazardous waste feedrates and could put some
well-controlled commercial incinerators in the untenable situation of
having to reduce the amount of hazardous waste that is treated at their
source. Our database verifies that such an outcome is in fact realistic.\92\
---------------------------------------------------------------------------
\92\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards'', September
2005, Section 17.4.
---------------------------------------------------------------------------
This type of standard would operate as a direct constraint on the
amount of hazardous waste that could be fed to the device, in effect
depriving a combustion source of its raw material. In this instance,
hazardous wastes could not be readily diverted to other units because
the low feeding hazardous waste sources tend not to be commercial
units. In these circumstances, there would be a significant adverse
nonair environmental impact. Hazardous waste is required to be treated
by Best Demonstrated Available Technology (BDAT) before it can be land
disposed. RCRA sections 3004 (d), (e), (g), and (m); Hazardous Waste
Treatment Council v. EPA, 866 F. 2d 355, 361 (D.C.Cir. 1990) (upholding
Best Demonstrated Available Technology treatment requirement). Most
treatment standards for organic pollutants in hazardous waste can only
be achieved by combustion. Leaving some hazardous wastes without a
[[Page 59447]]
treatment option is in derogation of these statutory requirements and
goals, and calls into question whether a treatment standard that has
significant adverse nonair environmental impacts must be viewed as best
performing. See Portland Cement Ass'n v. Ruckelshaus, 486 F. 2d 375 ,
386 (D.C. Cir. 1973); Essex Chemical Co. v. EPAEPA, 486 F. 2d 427, 439
(D.C. Cir. 1973). The commenter's statement that waste disposal policy
is not relevant to the MACT standard-setting process is not completely
correct, since section 112 (n) (7) of the Clean Air Act directs some
accommodation between MACT and RCRA standards for sources combusting
hazardous waste. Part of this accommodation is using a methodology to
evaluate best performing sources that evaluates as best performers
those using the best combination of hazardous waste feed control (among
other things, an existing control measure under RCRA rules) and system-
wide removal.
We assessed whether we could address this issue by subcategorizing
commercial incinerators and on-site incinerators. Applying the straight
emission approach to such a subcategorization scheme, however, yields
anomalous results due to the scarcity of available and complete
compliance test data from commercial incinerators. Calculated floor
levels for semivolatile metals and low volatile metals for the
commercial incinerator subcategory equate to 2,023 and 111 [mu]g/dscm,
respectively (both higher than the current interim standards).\93\ We
conclude that the SRE/Feed methodology better addresses this issue
because it yields floor levels that better represent the performance of
the best performing commercial incinerators and onsite incinerators
alike by applying equal weights to hazardous waste feed control and
back-end control in the ranking process.
---------------------------------------------------------------------------
\93\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards'', September
2005, Section 4. and Appendix C, Table ``E-INC-SVM-CT-COM'' and
Table ``E-INC-LVM-CT-COM''
---------------------------------------------------------------------------
EPA notes, however, that its choice of the SRE/Feed methodology is
justified independent of considerations of adverse impact on hazardous
waste treatment and disposal.
Comment: The commenter reiterates its comments with respect to
floor levels for new sources.
Response: EPA's previous responses to comments apply to both new
and existing source standards.
Comment: Two commenters recommend that EPA define the single best
performing source as that source with the lowest aggregated SRE/Feed
aggregated score (as proposed), as opposed to the source with the
lowest emissions among the best performing existing sources (an
approach on which we requested comment).
Response: We agree with the commenters because this is consistent
with our methodology for defining best performers for existing sources
and assessing their level of performance. We note, however, that with
respect to the new source standards, we encountered two instances where
the SRE/Feed methodology identified multiple sources with identical
single best aggregated scores, resulting in a tie for the best
performing source. This occurred for the mercury and low volatile metal
new source standards for incinerators. In these instances, EPA applied
a tie breaking procedure that resulted in selecting as the single best
performing source as that source (of the tied sources) with the lowest
emissions. We believe this is a reasonable interpretation of
section112(d)(3), which states the new source standard shall not be
less stringent than the emission control that is achieved in practice
by the best controlled similar source (``source'' being singular, not
plural). Moreover, we believe use of the emission level as the tie-
breaking criteria is reasonable, not only because it is a measure of
control, but because we have already fully accounted for hazardous
waste feedrate control and system removal efficiency in the ranking
methodology. To choose either of these factors to break the tie would
give that factor disproportionate weight.
C. Air Pollution Control Technology Methodologies for the Particulate
Matter Standard and for the Total Chlorine Standard for Hydrochloric
Acid Production Furnaces
At proposal, EPA used what we termed ``air pollution control
technology'' methodologies to estimate floor levels for particulate
matter from all source categories as a surrogate for non-mercury HAP
metals, and for total chlorine from hydrochloric acid furnace
production furnaces. 69 FR at 21225-226. Under this approach, we do not
estimate emission reductions attributable to feed control, but instead
assess the performance of back-end control technologies.\94\ We are
adopting the same methodologies for these HAP in the final rule.
Because the details of the approaches differ for particulate matter and
for total chlorine, we discuss the approaches separately below.
---------------------------------------------------------------------------
\94\ See generally USEPA, ``Technical Support Document for the
HWC MACT Standards, Volume III: Selection of MACT Standards'',
September 2005, Section 7.4 and 7.5.
---------------------------------------------------------------------------
1. Air Pollution Control Device Methodology for Particulate Matter
Our approach to establishing floor standards for particulate matter
raises three major issues.
The first issue is whether particulate matter is an appropriate
surrogate for non-enumerated HAP metals from all inputs, and for all
non-mercury HAP metals in raw material and fossil fuel inputs. This
issue is discussed at section IV.A of this part, where we conclude that
particulate matter is indeed a reasonable surrogate for these metal HAP.
The second issue is why EPA is not evaluating some type of feed
control for the particulate matter floor. There are two potential types
of feed control at issue: hazardous waste feed control of nonenumerated
metals, and feed control of non-mercury HAP metals in raw material and
fossil fuel inputs. With respect to feed control of non-enumerated
metals in hazardous waste, as discussed in more detail in section IV.A
of this part, we lack sufficient reliable data on non-enumerated metals
to assess their feedrates in hazardous waste. In addition, there are
significant questions about whether feedrates of the non-enumerated
metals can be optimized along with SVM and LVM feedrates. We also have
explained elsewhere why control of hazardous waste ash feedrate would
be technically inappropriate, since it would not properly assess feed
control of nonenumerated metals in hazardous waste. See also 69 FR at 21225.
We have also explained why we are not evaluating control of
feedrates of HAP metals in raw materials and fossil fuels to hazardous
waste combusters: it is an infeasible means of control. See section B
of this part. We consequently are not evaluating raw material and
fossil fuel ash feed control in determining the level of the various
floors for particulate matter.
a. The methodology. The final issue is the means by which EPA is
evaluating back-end control. Essentially, after determining (as just
explained) that back-end control is the means of controlling non-
mercury metal HAP and that particulate matter is a proper surrogate for
these metals, EPA is using its engineering judgment to determine what
the best type of air pollution control device (i.e., back-end control)
is to control particulate matter (and, of course, the contained HAP
metals). We then ascertain the level of performance by taking the
average of the requisite number of sources (either 12 % or five,
[[Page 59448]]
depending on the size of the source category) equipped with the best
back-end control with the lowest emissions.\95\ These floor standards
are therefore essentially established using a straight emissions
methodology. We have determined that baghouses (also termed fabric
filters) are generally the best air pollution control technology for
control of particulate matter, and that electrostatic precipitators are
the next best.
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\95\ As explained in the responses below, the approach varies
slightly if the requisite number of sources do not all use the best
back-end pollution control technology. In that case, EPA includes in
its pool of best performers the lowest emission levels from sources
using the next best pollution control technology.
---------------------------------------------------------------------------
b. Why not select the lowest emitters? Although sources with
baghouses tended to have the lowest emission levels for particulate
matter, this was not invariably the case. There are certain instances
when sources controlled with electrostatic precipitators (or, in one
instance, a venturi scrubber) had lower emissions in individual test
conditions than sources we identified as best performing which were
equipped with baghouses.\96\ Under the commenter's approach, we must
always use these lowest emitting sources as the best performers.
---------------------------------------------------------------------------
\96\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards,'' September
2005, Section 22.
---------------------------------------------------------------------------
We again disagree. We do not know if these sources equipped with
control devices other than baghouses with lower emissions in single
test conditions would actually have lower emissions over time than
sources equipped with baghouses because we cannot assess their
uncontrollable emissions variability over time. Our data suggests that
they likely are not better performing sources. We further conclude that
our statistical procedures that account for these sources' within test,
run-to-run emissions variability underestimates these sources long-term
emissions variability. This is not the case for sources equipped with
baghouses, where we have completely assessed, quantified, and accounted
for long-term, test-to-test emissions variability through application
of the universal variability factor.\97\ The sources equipped with
control devices other than baghouses with lower snapshot emissions data
could therefore have low emissions in part because they were operating
at the low end of the ``uncontrollable'' emissions variability profile
for that particular snapshot in time. The basis for these conclusions,
all of which are supported by our data, are found in section 16 of
volume III of the technical support document.
---------------------------------------------------------------------------
\97\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of MACT Standards,'' September
2005, Section 5.3.
---------------------------------------------------------------------------
We therefore conclude sources equipped with baghouses are the best
performers for particulate matter control not only based on engineering
judgment, but because we are able to reliably quantify their likely
performance over time. The straight emissions methodology ignores the
presence of long-term emissions variability from sources not equipped
with baghouses, and assumes without basis that these sources are always
better performing sources in instances where they achieved lower
snapshot emissions relative to the emissions from baghouses, emissions
that have notably already been adjusted to account for long-term
emissions variability.
A straight emissions approach also results in inappropriate floor
levels for particulate matter because it improperly reflects/includes
low ash feed when identifying best performing sources for particulate
matter. 69 FR at 21228. For example, the MACT pool of best performing
liquid fuel boilers for particulate matter under the straight emissions
approach includes eight sources, only one of which is equipped with a
back-end control device. These sources have low particulate matter
emissions solely because they feed low levels of ash. The average ash
inlet loadings for these sources are well over two orders of magnitude
lower than the average ash inlet loading for the best performing
sources that we identify with the Air Pollution Control Technology
approach. (Of course, since ash loadings are not a proper surrogate for
HAP metals, these sources' emissions are lowest for particulate matter
but not necessarily for HAP metals.) The straight emissions approach
would yield a particulate matter floor level of 0.0025 gr/dscf (with a
corresponding design level of 0.0015 gr/dscf). There is not one liquid
fuel boiler that is equipped with a back-end control that achieved this
floor level, much less the design level. The best performing source
under the air pollution control technology approach, which is equipped
with both a fabric filter and HEPA filter, did not even make the pool
of best performing sources for the straight emissions approach. Yet
this unit has an excellent ash removal efficiency of 99.8% and the
lower emitting devices' removal efficiencies are, for the most part, 0%
because they do not have any back-end controls. EPA believes that it is
arbitrary to say that these essentially uncontrolled devices must be
regarded as ``best performing'' for purposes of section 112(d)(3). We
therefore conclude that a straight emissions floor would not be
achievable for any source feeding appreciable levels of ash, even if
they all were to upgrade with baghouses, or baghouses in combination
with HEPA filters, and that a rote selection of lowest emitters as best
performers can lead to the nonsensical result of uncontrolled units
being classified as best performers.
Comment: Commenter claims end-of-stack control technology is not
the only factor affecting emissions of particulate matter, stating that
EPA admits that particulate matter emission levels are affected by the
feedrate of ash. Accordingly, the performance of a source's end-of-
stack control technology is not a reasonable estimate of that source's
total performance.
Response: The particulate matter standard serves as a surrogate
control for the non-enumerated metals in the hazardous waste streams
(for all source categories), and all nonmercury metal HAP in the
nonhazardous waste process streams (essentially, raw materials and
fossil fuels) for cement kilns, lightweight aggregate kilns, and liquid
fuel boilers. The commenter suggests that the APCD approach
inappropriately ignores HAP feed control in the assessment of best
performing sources. We conclude that it would not be appropriate to use
a methodology that directly assesses feed control, such as the SRE/Feed
methodology, to determine particulate matter floors. First, direct
assessment of total ash feed control would inappropriately assess and
seek to control (even though variability of raw material and fossil
fuel inputs are uncontrollable) raw material and fossil fuel HAP input,
as well as raw material and fossil fuel input. Controlling raw material
and fossil fuel HAP input is infeasible, as previously discussed. It
also inappropriately limits theses sources' feedstocks that are
necessary for their associated production process.
Second, we do not believe that developing a floor standard based on
hazardous waste feed control of nonenumerated metals (as opposed to
feed control of these metals in raw material and fossil fuels) is
appropriate or feasible. In part four, section IV.A, we explain that we
lack the data to reliably assess direct feedrate of these metals in
hazardous waste. In addition, we also discuss that it is unclear (the
lack of certainty resulting from the sparse available data) that
hazardous waste feed control of the nonenumerated metals is feasible.
The majority of these metals are not directly regulated under existing
RCRA requirements, so sources have optimized control of the other HAP
[[Page 59449]]
metals, raising issues of whether simultaneous optimization of feed
control of the remaining metals is feasible. Moreover, even if one were
to conclude that hazardous waste feed control is feasible for the
nonenumerated metal HAPs, hazardous waste ash feedrates are not
reliable indicators of nonmercury metal HAP feed control levels and are
therefore inappropriate parameters to assess in the MACT evaluation
process. For example, a source could reduce its ash feed input by
reducing the amount of silica in its feedstreams. This would not result
in feed control or emission reductions of metal HAP.\98\
---------------------------------------------------------------------------
\98\ For the same reason, even if feed control of total inputs
(i.e. raw material and fossil fuel as well as hazardous waste fuel)
were feasible, it would be technically inappropriate to use ash
feedrates as a surrogate: ash feed control allows sources to
selectively reduce the ash feeds without reducing the metal HAP
portion of that feed. Back-end control, in contrast, unselectively
removes a percentage of everything that is fed to the combustor.
---------------------------------------------------------------------------
Finally, hazardous waste ash feed control levels do not
significantly affect particulate matter emissions from cement kilns,
lightweight aggregate kilns, and solid fuel-fired boilers because the
majority of particulate matter that is emitted originates from the raw
material and nonhazardous fuel. Hazardous waste ash feed control levels
also do not significantly affect particulate matter emissions from
sources equipped with baghouses because these control devices are not
sensitive to particulate matter inlet loadings.\99\
---------------------------------------------------------------------------
\99\ See USEPA, ``Technical Support Document for the HWC MACT
Standards, Volume III: Selection of Mact Standards,'' September
2005, Section 3.1.
---------------------------------------------------------------------------
Thus, even if one were to conclude that the nonenumerated metal
HAPs are amenable to hazardous waste feed control, explicit use of ash
feed control in a MACT methodology would not assure that each source's
ability to control either nonmercury metal HAP or surrogate particulate
matter emissions is assessed. The Air Pollution Control Device
methodology identifies and assesses (with the surrogate particulate
matter standard) the known technology that always assures metal HAP
emissions are being controlled to MACT levels--that technology being
back-end control.
Comment: Commenter claims the Air Pollution Control Device approach
to calculate particulate matter floors is flawed because the
performance of back-end control technology alone does not reflect the
performance of the relevant best sources that otherwise would be
reflected if EPA were to assess performance based on the emission
levels each source achieved because, as EPA admits, it fails to account
for the effect of ash feed rate.
Response: We explain above why the Air Pollution Control Technology
approach properly identifies the relevant best performing sources for
purposes of controlling non-mercury metal HAP (measured as particulate
matter), irrespective of ash feed rates. Typically, this results in
selecting the sources with the lowest particulate matter emission
rates, the result the commenter advocates. This is because we evaluate
sources with the best-performing (e.g. lowest emitting) baghouses, and
particulate matter emissions from baghouses are not significantly
affected by inlet particulate matter loadings. Where the pool of best
performing sources includes sources operating some other type of back-
end control device (because insufficient numbers of sources are
equipped with baghouses to comprise 12% of sources, or five sources
(depending on the size of the source category)), we again use the
lowest particulate matter emission level from the sources equipped with
second best technology. Although these data do not reflect test-to-test
variability, they are the best remaining data in EPA's possession to
estimate performance and EPA is therefore, as required by section 112
(d) (3) (A) and (B), using the data to fill out the requisite
percentage of sources for calculating floors.
Comment: Commenter states that EPA has failed to demonstrate how it
reasonably estimated the actual performance of each source's end-of-
stack control technology because: (1) It failed to acknowledge that
there can be substantial differences between the performance of
different models of the same type of technology; and (2) it did not
explain or support its rankings of pollution control devices.
Response: As discussed in sections 7.4 and 16.2 of volume III of
the technical support document and C.1 of this comment response
section, we rank associated back-end air pollution control device
classes (e.g., baghouses, electrostatic precipitators, etc.), after
assessing particulate matter control efficiencies from hazardous waste
combustors that are equipped with the associated back-end control
class. The data used to make this assessment are included in our
database. We also evaluated particulate matter control efficiencies
from other similar source categories that also use these types of
control systems, such as municipal waste combustors, medical waste
incinerators, sewage sludge combustors, coal-fired boilers, oil fired
boilers, non-hazardous industrial waste combustors, and non-hazardous
waste Portland cement kilns.\100\
---------------------------------------------------------------------------
\100\ See USEPA, ``Technical Support Document for th HWC MACT
Standards, Volume III: Selection of MACT Standards,'' September
2005, Section 5.3 and 16.2, for further discussion.
---------------------------------------------------------------------------
After we assign a ranking score to each back-end control class, we
determine the number of sources that are using each of these control
technology classes. We then identify the MACT control technology or
technologies to be those best ranked back-end controls that are being
used by 12 percent of the sources (or used by five sources in instances
where there are fewer than 30 sources). We then look only at those
sources using MACT back-end control and rank order all these sources
first by back-end control type, and second by emissions. For example,
in instances where there is more than one MACT back-end control, we
array the emissions from the sources equipped with the top ranked back-
end controls from best to worst (i.e., lowest to highest), followed by
the emissions from sources equipped with the second ranked back-end
controls from best to worst, and so on. We then determine the
appropriate number of sources to represent 12 percent of the source
category (5 in instances where there are fewer than 30 sources). If 10
sources represented 12% of the sources in the source category, we would
then select the emissions from best ranked 10 sources in accordance
with this ranking procedure to calculate the MACT floor. This
methodology results in selection of lowest emitters using best back-end
air pollution control as pool of the best performing sources.
The commenter is correct that there can be differences between the
performance of different models of the same type of technology. We are
not capable of thoroughly assessing differences in designs of each air
pollution control device in a manner that could be used in the MACT
evaluation process, so that we would only select, for example,
baghouses of a certain type. Each baghouse, for example, will be
designed differently and thus will have different combinations of
design aspects that may or may not make that baghouse better than other
baghouses (e.g., bag types, air to cloth ratios, control mechanisms to
collect accumulated filter cake and maintain optimum pressure drops).
We also do not have detailed design information for each source's air
pollution control system; such an assessment would therefore not be
[[Page 59450]]
possible even if the information could be used to assess relative
performance.
We instead account for this difference by selecting sources with
the lowest emissions that are using the defined MACT back-end controls
to differentiate the performance among those sources that are using
that technology (the best performer being the source with the lowest
emissions, as just explained). For example, in situations where more
than 12% of the sources are using the single best control technology
(e.g., more than 12% of incinerators use baghouses to control
particulate matter), we use the emissions from the lowest emitting
sources equipped with baghouses to calculate the MACT floor. In
instances where there are two defined MACT technologies (i.e., 12% of
sources do not use the single best control technology), we use all the
emissions data from sources equipped with the best ranked control
class, and then subsequently use only the lowest emissions from the
sources equipped with the second ranked back-end controls.
Comment: EPA did not say how it picked the best performers if more
than twelve percent used the chosen technologies. If EPA used emissions
data to differentiate performance, the Agency is necessarily
acknowledging that emissions data are a valid measure of sources'
performance--in which case the Agency's claims to the contrary are
arbitrary and capricious.
Response: We did use emissions data to select the pool of best
performers where over 12% use the best type of emissions control
technology, as explained in the previous response. Emissions data is
obviously one means of measuring performance. EPA's position is that it
need not be the exclusive means, in part because doing so leads to
arbitrary results in certain situations. Our use of emission levels to
rank sources that use the best particulate matter control (i.e.,
baghouses) does not lead to arbitrary results, however. First, we are
assessing emission levels here as a means of differentiating sources
using a known type of pollution control technology. More importantly,
the adjusted emission levels from sources equipped with baghouses are
the most accurate measures of performance because these emissions have
been statistically adjusted to accurately account for long-term
variability through application of the universal variability factor.
Comment: Commenter states that EPA, in its support for its Air
Pollution Control Technology Approach used to calculate particulate
matter floors, claims that an emissions-based approach would result in
floor levels that ``could not necessarily be achieved by sources using
the chosen end-of-stack technology,'' citing 69 FR at 21228. Commenter
claims that it is settled law that standards do not have to be
achievable through the use of any given control technology, and that it
is also erroneous to establish floors at levels thought to be
achievable rather than levels sources actually achieve.
Response: EPA is not establishing floor levels based on assuring
the standards are achievable by a particular type of end-of-stack
technology (or, for that matter, any end-of-stack technology). The
floor levels in today's final rule reasonably estimate average
performance of the requisite percent of best performing sources without
regard for whether the levels themselves can be achieved by a
particular means. Floor standards for particulate matter are based on
the performance of those sources with the lowest emissions using the
best back-end control technology (most often baghouses, and sometimes
electrostatic precipitators). EPA uses this approach not to assure that
the floors are achievable by sources using these control devices, but
to best estimate performance of the best performing sources, including
these sources' variability.
2. Total Chlorine Standard for Hydrochloric Acid Production Furnaces
We are adopting the methodology we proposed to estimate floor
levels for total chlorine from hydrochloric acid production furnaces.
69 FR at 21225-226. As stated there, we are defining best performers as
those sources with the best total chlorine system removal efficiency.
We are not assessing a level of control attributable to control of
chlorine in feedstocks because this would simply prevent these furnaces
from producing their ultimate product. Further details are presented in
responses below.
Comment: Basing the standard for hydrochloric acid production
furnaces on the basis of system removal efficiency rather than chlorine
emission reduction is impermissible. Even though these devices' purpose
is to produce chlorinated product, the furnaces can use less
chlorinated inputs. EPA's proposed approach is surreptitious, an
impermissible attempt to assure that the standards are achievable by
all sources using EPA's chosen technology, the approach already
rejected in CKRC.
Response: EPA disagrees. There is nothing in the text of the
statute that compels an approach that forces sources to produce less
product to achieve a MACT floor standard. Yet this is the consequence
of the comment. If standards were based on levels of chlorine in
feedstock to these units, less product would be produced since there
would be less chlorine to recover. EPA has instead reasonably chosen to
evaluate best performing/best controlled sources for this source
category by measuring the efficiency of the entire chlorine emission
reduction system. Indeed, the situation here is similar to that in
Mossville, where polyvinyl chloride production units fed raw materials
containing varying amounts of vinyl chloride depending on the product
being produced. This led to variable levels of vinyl chloride in plant
emissions. Rather than holding that EPA must base a floor standard
reflecting the lowest amount of vinyl chloride being fed to these
units, the court upheld a standard estimating the amount of pollution
control achievable with back-end control. 370 F. 3d at 1240, 1243. In
the present case, as in Mossville, the standard is based on actual
performance of back-end pollution control (although here EPA is
assessing actual performance of the control technology rather than
estimating performance by use of a regulatory limit, making the
situation here a fortiorari from that in Mossville), and does not
reflect ``emission variations not related to technological
performance''. 370 F. 3d at 1240.
It also should be evident that EPA is not establishing a standard
to assure its achievability by a type of pollution control technology,
as the commenter mistakenly asserts. The standard for total chlorine is
based on the average of the best five sources `` best meaning those
sources with greatest (most efficient) system removal efficiencies. EPA
did not, as in CKRC, establish the standard using the highest emission
limit achieved by a source operating a particular type of control.
Comment: The commenter generally maintains that EPA's methodology
to determine total chlorine floors for hydrochloric acid production
furnaces fails to capture other means of HAP emission control that
otherwise would be captured if EPA were assess performance based on the
emission levels each source achieved.
Response: As discussed above, the standard for total chlorine is
based on the sources with the best system removal efficiencies. System
removal efficiency encompasses all means of MACT floor control when
assessing relative performance because: (1) Chlorine feed control is
not a MACT floor technology for these sources; and (2) the measure of
system removal efficiency accounts for every other controllable factor
that can affect
[[Continued on page 59451]]
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