Control of Emissions From Nonroad Large Spark Ignition Engines and Recreational Engines (Marine and Land-Based)

Related Material

Other Related Documents

[Federal Register: October 5, 2001 (Volume 66, Number 194)]
[Proposed Rules]
[Page 51097-51146]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05oc01-53]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 89, 90, 91, 94, 1048, 1051, 1065, and 1068
[AMS-FRL-7058-8]
RIN 2060-AI11

Control of Emissions From Nonroad Large Spark Ignition Engines
and Recreational Engines (Marine and Land-Based)

AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of proposed rulemaking.

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SUMMARY: In this action, we are proposing emission standards for
several groups of nonroad engines that cause or contribute to air
pollution but that have yet to be regulated by EPA. These engines
include large spark-ignition engines such as those used in forklifts
and airport tugs; recreational vehicles using spark-ignition engines
such as off-highway motorcycles, all-terrain vehicles, and snowmobiles;
and recreational marine diesel engines. Nationwide, engines and
vehicles in these various categories contribute to ozone, CO, and PM
nonattainment. These pollutants cause a range of adverse health
effects, especially in terms of respiratory impairment and related
illnesses. The proposed standards will help states achieve air quality
standards. In addition, the proposed standards will help reduce acute
exposure to CO, air toxics, and PM for operators and other people close
to the emission source. They will also help address other environmental
problems, such as visibility impairment in our national parks.
We expect that manufacturers will be able to maintain or even
improve the performance of their products when producing engines and
equipment meeting the proposed standards. In fact, many engines will
substantially reduce their fuel consumption, partially or completely
offsetting any costs associated with the emission standards. Overall,
we estimate the gasoline-equivalent fuel savings associated with the
anticipated changes in technology resulting from this rule would be
about 730 million gallons per year once the program is fully phased in.
The proposal also has several provisions to address the unique
limitations of small-volume manufacturers.

DATES: Comments: Send written comments on this proposed rule by
December 19, 2001. See Section X.B for more information about written
comments.
Hearings: We will hold a public hearing in the Washington, DC area
on October 24. We will hold a second public hearing on October 30 in
Denver, CO. See Section X.B for more information about public hearings.

ADDRESSES: Comments: You may send written comments in paper form or by
e-mail. We must receive them by the date indicated under DATES above.
Send paper copies of written comments (in duplicate if possible) to the
contact person listed below. You may also submit comments via e-mail to
``NRANPRM@epa.gov.'' In your correspondence, refer to Docket A-2000-01.
See Section X.B for more information on comment procedures.
Docket: EPA's Air Docket makes materials related to this rulemaking
available for review in Public Docket No. A-2000-01 at the following
address: U.S. Environmental Protection Agency (EPA), Air Docket (6102),
Room M-1500 (on the ground floor in Waterside Mall), 401 M Street, SW.,
Washington, DC 20460 between 8 a.m. to 5:30 p.m., Monday through
Friday, except on government holidays. You can reach the Air Docket by
telephone at (202) 260-7548, and by facsimile (202) 260-4400. We may
charge a reasonable fee for copying docket materials, as provided in 40
CFR part 2.
Hearings: We will hold a public hearing on October 24, 2001 at
Washington Dulles Airport Marriott, Dulles, VA 20166 (703-471-9500). We
will hold a second public hearing October 30, 2001 at Doubletree Hotel,
3203 Quebec Street, Denver, CO 80207 (303-321-3333). If you want to
testify at a hearing, notify the contact person listed below at least
ten days before the date of the hearing. See Section X.B for more
information on the public-hearing procedures.

FOR FURTHER INFORMATION CONTACT: Margaret Borushko, U.S. EPA, National
Vehicle and Fuels Emission Laboratory, 2000 Traverwood, Ann Arbor, MI
48105; Telephone (734) 214-4334; Fax: (734) 214-4816; E-mail:
borushko.margaret@epa.gov.

SUPPLEMENTARY INFORMATION:

Regulated Entities

This proposed action would affect companies that manufacture or
introduce into commerce any of the engines or vehicles that would be
subject to the proposed standards. These include: spark-ignition
industrial engines such as those used in forklifts and airport tugs;
recreational vehicles such as off-highway motorcycles, all-terrain
vehicles, and snowmobiles; and recreational marine diesel engines. This
proposed action would also affect companies buying engines for
installation in nonroad equipment. There are also proposed requirements
that apply to those who rebuild any of the affected nonroad engines.
Regulated categories and entities include:

------------------------------------------------------------------------
NAICS Examples of potentially
Category codes a SIC codes regulated entities
------------------------------------------b-----------------------------
Industry............... 333618 3519 Manufacturers of new
nonroad SI engines,
new marine engines.
Do............... 333111 3523 Manufacturers of farm
equipment.
Do............... 333112 3531 Manufacturers of
construction
equipment,
recreational marine
vessels.
Do............... 333924 3537 Manufacturers of
industrial trucks.
Do............... 811310 7699 Engine repair and
maintenance.
Do............... 336991 .......... Motorcycles and
motorcycle parts
manufacturers.
Do............... 336999 .......... Snowmobiles and all-
terrain vehicle
manufacturers.
Do............... 421110 .......... Independent Commercial
Importers of Vehicles
and Parts.
------------------------------------------------------------------------
a North American Industry Classification System (NAICS).
b Standard Industrial Classification (SIC) system code.

This list is not intended to be exhaustive, but rather provides a
guide regarding entities likely to be regulated by this action. To
determine whether particular activities may be regulated by this
action, you should carefully examine the proposed regulations. You may
direct questions regarding the applicability of this action to the
person listed in FOR FURTHER INFORMATION CONTACT.

[[Page 51099]]

Obtaining Electronic Copies of the Regulatory Documents

The preamble, regulatory language, Draft Regulatory Support
Document, and other rule documents are also available electronically
from the EPA Internet Web site. This service is free of charge, except
for any cost incurred for internet connectivity. The electronic version
of this proposed rule is made available on the day of publication on
the primary web site listed below. The EPA Office of Transportation and
Air Quality also publishes Federal Register notices and related
documents on the secondary web site listed below.

1. http://www.epa.gov/fedrgstr/EPA-AIR/ (either select desired
date or use Search feature)
2. http://www.epa.gov/otaq/ (look in What's New or under the specific
rulemaking topic)

Please note that due to differences between the software used to
develop the documents and the software into which the document may be
downloaded, format changes may occur.

Table of Contents

I. Introduction
A. Overview
B. How Is This Document Organized?
C. What Categories of Vehicles and Engines Are Covered in This
Proposal?
D. What Requirements Are We Proposing?
E. Why Is EPA Taking This Action?
F. Putting This Proposal Into Perspective
II. Public Health and Welfare Effects of Emissions From Covered
Engines
A. Background
B. What Are the Public Health and Welfare Effects Associated
With Emissions From Nonroad Engines Subject to the Proposed
Standards?
C. What Is the Inventory Contribution From the Nonroad Engines
and Vehicles That Would Be Subject to This Proposal?
D. Regional and Local-Scale Public Health and Welfare Effects
III. Nonroad: General Concepts
A. Scope of Application
B. Emission Standards and Testing
C. Demonstrating Compliance
D. Other Concepts
IV. Large SI Engines
A. Overview
B. Large SI Engines Covered by This Proposal
C. Proposed Standards
D. Proposed Testing Requirements and Supplemental Emission
Standards
E. Special Compliance Provisions
F. Technological Feasibility of the Standards
V. Recreational Marine Diesel Engines
A. Overview
B. Engines Covered by This Proposal
C. Proposed Standards for Marine Diesel Engines
D. Proposed Testing Requirements
E. Special Compliance Provisions
F. Technical Amendments
G. Technological Feasibility
VI. Recreational Vehicles and Engines
A. Overview
B. Engines Covered by this Proposal
C . Proposed Standards
D. Proposed Testing Requirements
E. Special Compliance Provisions
F. Technological Feasibility of the Standards
VII. General Nonroad Compliance Provisions
A. Miscellaneous Provisions (Part 1068, Subpart A)
B. Prohibited Acts and Related Requirements (Part 1068, Subpart
B)
C. Exemptions (Part 1068, Subpart C)
D. Imports (Part 1068, Subpart D)
E. Selective Enforcement Audit (Part 1068, Subpart E)
F. Defect Reporting and Recall (Part 1068, Subpart F)
G. Public Hearings (Part 1068, Subpart G)
VIII. General Test Procedures
A. General Provisions
B. Laboratory Testing Equipment
C. Laboratory Testing Procedures
IX. Projected Impacts
A. Environmental Impact
B. Economic Impact
C. Cost per Ton of Emissions Reduced
D. Additional Benefits
X. Public Participation
A. How Do I Submit Comments?
B. Will There Be a Public Hearing?
XI. Administrative Requirements
A. Administrative Designation and Regulatory Analysis (Executive
Order 12866)
B. Regulatory Flexibility Act
C. Paperwork Reduction Act
D. Intergovernmental Relations
E. National Technology Transfer and Advancement Act
F. Protection of Children (Executive Order 13045)
G. Federalism (Executive Order 13132)
H. Energy Effects (Executive Order 13211)
I. Plain Language

I. Introduction

A. Overview

Air pollution is a serious threat to the health and well-being of
millions of Americans and imposes a large burden on the U.S. economy.
Ground-level ozone, carbon monoxide, and particulate matter are linked
to potentially serious respiratory health problems, especially
respiratory effects and environmental degradation, including visibility
impairment in our precious national parks. Over the past quarter
century, state and federal representatives have established emission-
control programs that significantly reduce emissions from individual
sources. Many of these sources now pollute at only a small fraction of
their precontrol rates. This proposal further addresses these air-
pollution concerns by proposing national emission standards for several
types of nonroad engines and vehicles that are currently unregulated.
These include industrial spark-ignition engines such as those used in
forklifts and airport tugs; recreational vehicles such as off-highway
motorcycles, all-terrain vehicles, and snowmobiles; and recreational
marine diesel engines.\1\ The proposed standards are a continuation of
the process of establishing standards for nonroad engines and vehicles,
as required by Clean Air Act section 213(a)(3). All the nonroad engines
subject to this proposal are still unregulated emission sources.
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\1\ Diesel-cycle engines, referred to simply as ``diesel
engines'' in this document, may also be referred to as compression-
ignition (or CI) engines. These engines typically operate on diesel
fuel, but other fuels may also be used. Otto-cycle engines (referred
to here as spark-ignition or SI engines) typically operate on
gasoline, liquefied petroleum gas, or natural gas.
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Nationwide, these engines are a significant source of mobile-source
air pollution. They currently account for about 13 percent of mobile-
source hydrocarbon (HC) emissions, 6 percent of mobile-source carbon
monoxide (CO) emissions, 3 percent of mobile-source oxides of nitrogen
( NO_X) emissions, and 1 percent of mobile-source particulate
matter (PM) emissions.\2\ The proposed standards will reduce exposure
to these emissions and help avoid a range of adverse health effects
associated with ambient ozone, CO, and PM levels, especially in terms
of respiratory impairment and related illnesses. In addition, the
proposed standards will help reduce acute exposure to CO, air toxics,
and PM for persons who operate or who work with or are otherwise active
in close proximity to these engines. They will also help address other
environmental problems associated with these engines, such as
visibility impairment in our national parks and other wilderness areas
where recreational vehicles and marine engines are often used.
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\2\ While we characterize emissions of hydrocarbons, this can be
used as a surrogate for volatile organic compounds (VOC), which is a
broader group of compounds.
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This proposal follows a final finding published on December 7, 2000
(65 FR 76790). Under this finding, EPA found that industrial spark-
ignition (SI) engines rated above 19 kilowatts (kW), as well as all
land-based recreational nonroad spark-ignition engines, cause or
contribute to air quality nonattainment in more than one ozone or
carbon monoxide (CO) nonattainment area. We also found that particulate
matter (PM) emissions from these engines cause or contribute to air
pollution that may reasonably be anticipated to endanger public health
or welfare.
This proposal also follows EPA's Advance Notice of Proposed

[[Page 51100]]

Rulemaking (ANRPM) published on December 7, 2000 (65 FR 76797). In that
Advance Notice, we provided an initial overview of possible regulatory
strategies for the nonroad vehicles and engines and invited early input
to the process of developing standards. We received comments on the
Advance Notice from a wide variety of stakeholders, including the
engine industry, the equipment industry, various governmental bodies,
environmental groups, and the general public. The Advance Notice, the
related comments, and other new information provide the framework for
this proposal.

B. How Is This Document Organized?

This proposal covers engines and vehicles that vary in design and
use, and many readers may be interested in only one or two of the
applications. For the purpose of this proposal, we have chosen to group
engines by common application (e.g., recreational land-based engines,
marine engines, large spark-ignition engines used in commercial
applications). We have attempted to organize the document in a way that
allows each reader to focus on the applications of particular interest.
The Air Quality discussion in Section II is general in nature, however,
and applies to all the categories covered by this proposal.
The next four sections contain our proposal for the nonroad engines
that are the subject of this action. Sections III contains some general
concepts that are relevant to all of the nonroad engines covered by
this proposal. Section IV through VI present information specific to
each of the nonroad applications covered by the proposal, including
standards, effective dates, testing information, and other specific
requirements.
Sections VII and VIII describe a wide range of compliance and
testing provisions that apply generally to engines and vehicles from
all the nonroad engine and vehicle categories included in this
proposal. Several of these provisions apply not only to manufacturers,
but also to equipment manufacturers installing certified engines,
remanufacturing facilities, operators, and others. Therefore, all
affected parties should read the information contained in this section.
Section IX summarizes the projected impacts and a discussion of the
benefits of this proposal. Finally, Sections X and XI contain
information about public participation, how we satisfied our
administrative requirements, and the statutory provisions and legal
authority for this proposal.
The remainder of this Section I summarizes important background
information about this proposal, including the engines covered, the
proposed standards, and why we are proposing them.

C. What Categories of Vehicles and Engines Are Covered in This
Proposal?

This proposal presents regulatory strategies for new nonroad
vehicles and engines that have yet to be regulated under EPA's nonroad
engine programs. This proposal covers the following engines:
Land-based spark-ignition recreational engines, including
those used in snowmobiles, off-highway motorcycles, and all-terrain
vehicles. For the purpose of this proposal, we are calling this group
of engines ``recreational vehicles,'' even though all-terrain vehicles
can be used for commercial purposes.
Land-based spark-ignition engines rated over 19 kW,
including engines used in forklifts, generators, airport tugs, and
various farm, construction, and industrial equipment. This category
also includes auxiliary marine engines, but does not include engines
used in recreational vehicles. For the purpose of this proposal, we are
calling this group of engines ``Large SI engines.''
Recreational marine diesel engines.
This proposal covers new engines that are used in the United
States, whether they are made domestically or imported.\3\ A more
detailed discussion of the meaning of the terms ``new,'' ``imported,''
as well as other terms that help define the scope of application of
this proposal, is contained in Section III of this preamble.
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\3\ For this proposal, we consider the United States to include
the States, the District of Columbia, the Commonwealth of Puerto
Rico, the Commonwealth of the Northern Mariana Islands, Guam,
American Samoa, the U.S. Virgin Islands, and the Trust Territory of
the Pacific Islands.
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We intended to include in this proposal emission standards for two
additional vehicle categories: new exhaust emission standards for
highway motorcycles and new evaporative emission standards for marine
vessels powered by spark-ignition engines. Proposals for these two
categories are not included in the September 14 deadline mandated by
the courts, as is the case for the remaining contents that appear in
today's proposed rule. We are committed to issue proposals regarding
these categories within the next two to three months. Interested
parties will have an opportunity to comment on issues associated with
the proposed standards for these two categories during the public
review period that will begin after a subsequent proposal or proposals
are issued.

D. What Requirements Are We Proposing?

The fundamental requirement for engines under Clean Air Act section
213 is to meet EPA's emission standards. The Act requires that
standards achieve the greatest degree of emission reduction achievable
through the application of technology that will be available, giving
appropriate consideration to cost, noise, energy, and safety factors.
Other requirements such as applying for certification, labeling
engines, and meeting warranty requirements define a process for
implementing the proposed program in an effective way.
With regard to Large SI engines, we are proposing a two-phase
program. The first phase of the standards, to go into effect in 2004,
are the same as those recently adopted by the California Air Resources
Board. These standards will reduce combined HC and NO_X
emissions by nearly 75 percent, based on a steady-state test. In 2007,
we propose to supplement these standards by setting limits that would
require optimizing the same technologies but would be based on a
transient test cycle. New requirements for evaporative emissions and
engine diagnostics would also start in 2007.
For recreational vehicles, we are proposing emission standards for
snowmobiles separately from off-highway motorcycles and all-terrain
vehicles. For snowmobiles, we are proposing a first phase of standards
for HC and CO emissions based on the use of clean carburetion or 2-
stroke electronic fuel injection (EFI) technology, and a second phase
of emission standards for snowmobiles that would involve significant
use of direct fuel injection 2-stroke technology, as well as possible
limited conversion to 4-stroke engines. For off highway motorcycles and
all-terrain vehicles, we are proposing standards that would result in a
50-percent reduction and is based mainly on moving these engines from
2-stroke to 4-stroke technology. In addition, we are proposing a second
phase of standards for all-terrain vehicles that would require some
catalyst use.
We are also proposing voluntary Blue Sky Series emission standards
for recreational marine diesel engines and industrial spark-ignition
engines. Blue Sky Series emission standards are intended to encourage
the introduction and more widespread use of low-emission technologies.
Manufacturers could be motivated to exceed emission

[[Page 51101]]

requirements either to gain early experience with certain technologies
or as a response to market demand or local government programs. For
recreational vehicles, we are proposing separate voluntary standards
based more on providing consumers with an option of buying low-emission
models.

E. Why Is EPA Taking This Action?

There are important public health and welfare reasons supporting
the standards proposed in this document. As described in Section II.B,
these engines contribute to air pollution which causes public health
and welfare problems. Emissions from these engines contribute to ground
level ozone and ambient CO and PM levels. Exposure to ground level
ozone, CO, and PM can cause serious respiratory problems. These
emissions also contribute to other serious environmental problems,
including visibility impairment.
We believe existing technology that can be applied to these engines
would reduce emissions of these harmful pollutants. Manufacturers can
reduce 2-stroke engine emissions by improving fuel management and
calibration. In addition, many of the existing 2-stroke engines in
these categories can be converted to 4-stroke technology. Finally,
there are modifications that can be made to 4-stroke engines, often
short of requiring catalysts, that can reduce emissions even further.

F. Putting This Proposal Into Perspective

This proposal should be considered in the broader context of EPA's
nonroad emission-control programs; state-level programs, particularly
in California; and international efforts. Each of these are described
in more detail below.
1. EPA's Nonroad Emission-Control Programs
a. EPA's nonroad process. Clean Air Act section 213(a)(1) directs
us to study emissions from nonroad engines and vehicles to determine,
among other things, whether these emissions ``cause, or significantly
contribute to, air pollution that may reasonably be anticipated to
endanger public health or welfare.'' Section 213(a)(2) further required
us to determine whether emissions of CO, VOC, and NO_X from
all nonroad engines significantly contribute to ozone or CO emissions
in more than one nonattainment area. If we determine that emissions
from all nonroad engines were significant contributors, section
213(a)(3) then requires us to establish emission standards for classes
or categories of new nonroad engines and vehicles that in our judgment
cause or contribute to such pollution. We may also set emission
standards under section 213(a)(4) regulating any other emissions from
nonroad engines that we find contribute significantly to air pollution.
We completed the Nonroad Engine and Vehicle Emission Study,
required by Clean Air Act section 213(a)(1), in November 1991.\4\ On
June 17, 1994, we made an affirmative determination under section
213(a)(2) that nonroad emissions are significant contributors to ozone
or CO in more than one nonattainment area. We also determined that
these engines make a significant contribution to PM and smoke emissions
that may reasonably be anticipated to endanger public health or
welfare. In the same document, we set a first phase of emission
standards (now referred to as Tier 1 standards) for land-based nonroad
diesel engines rated at or above 37 kW. We recently added a more
stringent set of Tier 2 and Tier 3 emission levels for new land-based
nonroad diesel engines at or above 37 kW and adopted Tier 1 standards
for land-based nonroad diesel engines less than 37 kW. Our other
emission-control programs for nonroad engines are listed in Table I.F-
1. This proposal takes another step toward the comprehensive nonroad
engine emission-control strategy envisioned in the Act by proposing an
emission-control program for the remaining unregulated nonroad engines.
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\4\ This study is available in docket A-92-28.

Table I.F-1.--EPA's Nonroad Emission-Control Programs
----------------------------------------------------------------------------------------------------------------
Engine category Final rulemaking Date
----------------------------------------------------------------------------------------------------------------
Land-based diesel engines ³ 56 FR 31306 June 17, 1994.
37 kW--Tier 1.
Spark-ignition engines £ 19 60 FR 34581 July 3, 1995.
kW--Phase 1.
Spark-ignition marine................ 61 FR 52088 October 4, 1996.
Locomotives.......................... 63 FR 18978 April 16, 1998.
Land-based diesel engines--Tier 1 and 63 FR 56968 October 23, 1998.
Tier 2 for engines 37 kW.
--Tier 2 and Tier 3 for engines
³ 37 kW
Commercial marine diesel............. 64 FR 73300 December 29, 1999.
Spark-ignition engines £ 19 64 FR 15208 March 30, 1999.
kW (Non-handheld)--Phase 2.
Spark-ignition engines £ 19 65 FR 24268 April 25, 2000.
kW (Handheld)--Phase 2.
----------------------------------------------------------------------------------------------------------------

b. National standards for marine engines. In the October 1996 final
rule for spark-ignition marine engines, we set standards only for
outboard and personal watercraft engines. We decided not to finalize
emission standards for sterndrive or inboard marine engines at that
time. Uncontrolled emission levels from sterndrive and inboard marine
engines were already significantly lower than the outboard and personal
watercraft engines. We did, however, leave open the possibility of
revisiting the need for emission standards for sterndrive and inboard
engines in the future.
In December 1999, we published emission standards for commercial
marine diesel engines. To allow more time to evaluate the potential
impact of the proposed emission limits on the recreational vessel
industry, we did not include recreational propulsion marine diesel
engines in that rulemaking.
c. National standards for land-based spark-ignition engines. The
standards we have set to date for land-based, spark-ignition nonroad
engines apply to engines typically used in lawn and garden
applications. In adopting these emission standards, we decided not to
include engines rated over 19 kW or any engines used in recreational
vehicles. The proposed emission-control program in this document
addresses these remaining unregulated engines.
2. State Initiatives
Under Clean Air Act section 209, California has the authority to
regulate emissions from new motor vehicles and new motor vehicle
engines. California may also regulate emissions from nonroad engines,
with the exception of

[[Page 51102]]

new engines used in locomotives and new engines used in farm and
construction equipment rated under 130 kW.\5\ So far, the California
Air Resources Board (California ARB) has adopted requirements for four
groups of nonroad engines: (1) Diesel- and Otto-cycle small off-road
engines rated under 19 kW; (2) new land-based nonroad diesel engines
rated over 130 kW; (3) land-based nonroad recreational engines,
including all-terrain vehicles, snowmobiles, off-highway motorcycles,
go-carts, and other similar vehicles; and (4) new nonroad SI engines
rated over 19 kW. They have approved a voluntary registration and
control program for existing portable equipment.
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\5\ The Clean Air Act limits the role states may play in
regulating emissions from new motor vehicles and nonroad engines.
California is permitted to establish emission standards for new
motor vehicles and most nonroad engines; other states may adopt
California's programs (sections 209 and 177 of the Act).
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Other states may adopt emission standards set by California ARB,
but are otherwise preempted from setting emission standards for new
engines or vehicles. In contrast, there is generally no federal
preemption of state initiatives related to the way individuals use
individual engines or vehicles.
a. Industrial SI engines. California ARB in 1998 adopted
requirements that apply to new nonroad engines rated over 25 hp
produced for California starting in 2001. These standards phase in over
three years, during which manufacturers show only that engines meet the
standards before they start in service. Beginning in 2004, the
standards apply to 100 percent of engines sold in California, including
a requirement to show that an engine meets emission standards
throughout its useful life. As described above, these standards do not
apply to engines under 130 kW used in farm or construction equipment.
Texas has adopted the California ARB emission standards statewide
starting in 2004.
b. Off-highway motorcycles and all-terrain vehicles. California
established standards for off-highway motorcycles and all-terrain
vehicles which took effect in January 1997 (1999 for vehicles with
engines of 90 cc or less). The standards are 1.2 g/km HC and 15.0 g/km
CO and are based on the highway motorcycle chassis test procedures.
Manufacturers may certify all-terrain vehicles to optional standards,
which are based on the utility engine test procedure.\6\ These
standards are 12 g/hp-hr HC+NO_X and 300 g/hp-hr CO, for all-
terrain vehicles with engine displacements less than 225 cubic
centimeters (cc) and 10 g/hp-hr NC+NO_X and 300 g/hp-hr CO,
for all-terrain vehicles with engine displacement greater than 225 cc.
The utility engine test procedure is the procedure over which Small SI
engines are tested. The stringency level of the standards was based on
the emissions performance of 4-stroke engines and advanced 2-stroke
engines equipped with a catalytic converter. California anticipated
that the standards would be met initially through the use of high
performance 4-stroke engines.
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\6\ Notice to Off-Highway Recreational Vehicle Manufacturers and
All Other Interested Parties Regarding Alternate Emission Standards
for All-Terrain Vehicles, Mail Out #95-16, April 28, 1995,
California ARB (Docket A-2000-01, document II-D-06).
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California revisited the program in the 1997 time frame because a
lack of certified product from manufacturers was reportedly creating
economic hardship for dealerships. The number of certified off-highway
motorcycle models was particularly inadequate.\7\ In 1998, California
revised the program, allowing the use of uncertified products in off-
highway vehicle recreation areas with regional/seasonal use
restrictions. Currently, noncomplying vehicles can be legally sold in
California and used in attainment areas year-round and in nonattainment
areas during months when exceedances of the state ozone standard are
not expected. For enforcement purposes, certified and uncertified
products are identified respectively with green and red stickers. Only
about one-third of off-highway motorcycles sold in California are
certified.
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\7\ Initial Statement of Reasons, Public Hearing to Consider
Amendments to the California Regulations for New 1997 and Later Off-
highway Recreational Vehicles and Engines, California ARB, October
23, 1998 (Docket A-2000-01, II-D-08).
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3. Actions in Other Countries
a. European action--Recreational Marine Engines. The European
Commission has proposed emission standards for recreational marine
engines, including both diesel and gasoline engines. These requirements
would apply to all new engines sold in member countries. The numerical
emission standards for recreational diesel marine engines, shown in
Table I.F-2, consist of the Annex VI NO_X standard for small
marine diesel engines, the rough equivalent of Nonroad Diesel Tier 1
emission standards for HC and CO. Emission testing is to be conducted
using the ISO D2 duty cycle for constant-speed engines and the ISO E5
duty cycle for all other engines. Table I.F-2 also presents average
baseline emissions based on data that we have collected. These data are
presented in Chapter 4 of the Draft Regulatory Support Document. We
have received comment that we should apply these standards in the U.S.,
but the proposed European emission standards for recreational marine
diesel engines may not result in a decrease in emissions, and may even
allow an increase in emissions from engines operated in the U.S.

Table I.F-2.--Proposed European Emission Standards for Recreational
Marine Diesel Engines
------------------------------------------------------------------------
Emission Baseline
standard emissions
Pollutant (g/k W- (g/k W-
hr) hr)
------------------------------------------------------------------------
NO_X............................................... 9.8 8.9
PM................................................ 1.4 0.2
HC................................................ \a\ 1.5 0.3
CO................................................ 5.0 1.3
------------------------------------------------------------------------
\a\ Increases slightly with increasing engine power rating.

b. International Maritime Organization--CI Marine Engines. In
response to growing international concern about air pollution and in
recognition of the highly international nature of maritime
transportation, the International Maritime Organization developed a
program to reduce NO_X and SOx emissions from marine vessels.
No restrictions on PM, HC, or CO emissions were considered. The
NO_X provisions, contained in Regulation 13 of Annex VI to
the International Convention on the Prevention of Pollution from Ships
(MARPOL 73/78), specify that each diesel engine with a power output of
more than 130 kW installed on a ship constructed on or after January 1,
2000, or that undergoes a major conversion on or after January 1, 2000,
must meet the NO_X emission standards in Table I.F-3.\8\ The
Annex does not distinguish between marine diesel engines installed on
recreational or commercial vessels; all marine diesel engines above 130
kW would be subject to the standards regardless of their use.
---------------------------------------------------------------------------

\8\ Additional information about the MARPOL Annex VI
NO_X standards can be found in the documents for our
commercial marine diesel standards, which can be found on our
website (http://www.epa.gov/otaq/marine.htm). That website also
contains facts sheets and other information about the Annex.

Table I.F-3.--MARPOL Annex VI NO_X Standards
------------------------------------------------------------------------
NO_X (g/kW-
Engine speed (n = engine speed, rpm) hr)
------------------------------------------------------------------------
n 130 rpm.................................................. 17.0
130 rpmn2000 rpm................................ 45*n(-0.2)

[[Page 51103]]

n ³ 2000......................................... 9.8
------------------------------------------------------------------------

After several years of negotiation, the Member States of the
International Maritime Organization adopted a final version of Annex VI
on September 26, 1997. As stipulated in Article 6 of the Agreement, the
Annex will go into force when fifteen States, the combined merchant
fleets of which constitute not less than 50 percent of the gross
tonnage of the world's merchant shipping, have ratified it. As of
today, three countries have ratified the Annex (Norway, Sweden,
Singapore), representing about 7 percent of the world fleet.
Pending entry into force, ship owners and vessel manufacturers are
expected to install compliant engines on relevant ships beginning with
the date specified in Regulation 13, January 1, 2000. In addition, ship
owners are expected to bring existing engines into compliance if the
engines undergo a major conversion on or after that date.\9\ As defined
in Regulation 13 of Annex VI, a major conversion is defined to include
those situations when the engine is replaced by a new engine, it is
substantially modified, or its maximum continuous rating is increased
by more than 10 percent. To facilitate this process, and to allow
engine manufacturers to certify their engines before the Annex goes
into force, we set up a process for manufacturers to obtain a Statement
of Voluntary Compliance.\10\ This document will be exchangeable for an
Engine International Air Pollution Prevention (EIAPP) certificate once
the Annex goes into effect for the United States.
---------------------------------------------------------------------------

\9\ As defined in Regulation 13 of Annex VI, a major conversion
means the engine is replaced by a new engine, it is substantially
modified, or its maximum continuous rating is increased by more than
10 percent.
\10\ For more information about our voluntary certification
program, see ``guidance for Certifying to MARPOL Annex VI,'' VPCD-
99-02. This letter is available on our website: http://www.epa.gov/
otaq/regs/nonroad/marine/ci/imolettr.pdf.
---------------------------------------------------------------------------

II. Public Health and Welfare Effects of Emissions From Covered
Engines

A. Background

This proposal contains regulatory strategies for three sets of new
nonroad vehicles and engines that cause or contribute to air pollution
but that have not been regulated under EPA's nonroad engine programs.
The three sets of nonroad vehicles and engines are:
Large Industrial Spark Ignition Engines. These are spark-
ignition nonroad engines rated over 19 kW used in commercial
applications. These include engines used in forklifts, electric
generators, airport tugs, and a variety of other construction, farm,
and industrial equipment. Many of these engines, such as those used in
farm and construction equipment, are operated outdoors, predominantly
during warmer weather and often in or near heavily-populated urban
areas where they contribute to ozone formation and ambient CO and PM
levels. These engines are also often operated in factories, warehouses,
and large retail outlets throughout the year, where they contribute to
high exposure levels to personnel who work with or near this equipment
as well as to ozone formation and ambient CO and PM levels. For the
purpose of this proposal, we are calling these ``Large SI engines.''
Nonroad Spark-Ignition Recreational Engines. These are
spark-ignition nonroad engines used primarily in recreational
applications. These include off-highway motorcycles, all-terrain-
vehicles and snowmobiles. Some of these engines, particularly those
used on all-terrain vehicles, are increasingly used for commercial
purposes within urban areas, especially for mowing lawns and hauling
loads. These vehicles are typically used in suburban and rural areas,
where they contribute to ozone formation and ambient CO, and PM levels.
All these vehicles, and snowmobiles in particular, contribute to
visibility impairment problems in our national and state parks. For the
purpose of this proposal, we are calling this group of engines
``recreational vehicles.''
Marine Engines. These are marine diesel engines that are
used on recreational vessels such as yachts, cruisers, and other types
of pleasure craft. Recreational marine engines are primarily used in
warm weather and therefore contribute to ozone formation and PM levels,
especially in marinas, which are often located in nonattainment areas.
Nationwide, these engines and vehicles are a significant source of
mobile-source air pollution. As described in Section II.C, below, they
currently account for about 13 percent of national mobile-source HC
emissions, 6 percent of mobile-source CO emissions, 3 percent of
mobile-source NO_X emissions, and 1 percent of mobile-source
PM emissions. Recreational vehicles by themselves account for nearly 10
percent of national mobile-source HC emissions and about 3 percent of
national mobile-source CO emissions. Within national parks, snowmobiles
are significant contributors to ambient concentrations of fine
particulate matter, a leading component of visibility impairment. By
reducing these emissions, the proposed standards would provide
assistance to states facing ozone and CO air quality problems, which
can cause a range of adverse health effects, especially in terms of
respiratory impairment and related illnesses. States are required to
develop plans to address visibility impairment in national parks, and
the reductions proposed in this rule would assist states in those
efforts.
In addition, the proposed standards would help reduce acute
exposure to CO and air toxics for forklift operators, snowmobile users,
national and state park attendants, and other people who may be at
particular risk because they operate or work or are otherwise active
for long periods of time in close proximity to this equipment.
Emissions from these vehicles and equipment can be very high on a per
engine basis. In addition, the equipment (e.g., forklifts) is often
used in enclosed areas. Similarly, exposure can be intensified for
snowmobile riders who follow a group of other rides along a trail,
since those riders are exposed to the emissions of all the other
snowmobiles riding ahead. As summarized below and explained in greater
detail in the Draft Regulatory Support Document for this proposal, CO
emissions have been directly associated with cardisvascular and other
health problems, and many types of hydrocarbons are also air toxics.
The standards proposed in this document would require the use of
cleaner emission-control technologies. For Large SI engines, we are
proposing a two-phase program that will take fuel effects into account.
The first phase consists of one set of standards that would apply to
all engines regardless of fuel (i.e., gasoline, LPG, CNG). These
standards are identical to those recently adopted by California Air
Resources Board (CARB) and are based on a steady-state test. The second
phase of standards is more stringent than the California standards. The
numerical limits differ depending on fuel type and would require
optimizing the same emission-control technologies used in Phase 1 but
would be based on a transient duty test cycle. These standards would
also include new requirements for evaporative emissions and engine
diagnostics.
For marine engines, we are proposing to set new standards that
would require recreational diesel marine engines to adopt the emission-
control technology

[[Page 51104]]

that will be in use on commercial diesel marine engines.
For nonroad recreational vehicles, we are proposing standards that
would require snowmobiles to use cleaner 2-stroke technologies (e.g.,
clean carburetion, electronic fuel injection). For off-highway
motorcycles and all-terrain vehicles, we are proposing standards that
would effectively require manufacturers to use more 4-stroke technology
for most engines. A second phase of proposed standards for all-terrain
vehicles is based on catalyst technology.
When the proposed emission standards are fully implemented in 2020,
we expect a 79 percent reduction in HC emissions, 75 percent reduction
in NO_X emissions, and 56 percent reduction in CO emissions
from these engines, equipment, and vehicles (see Section IX below for
more details). These emission reductions will reduce ambient
concentrations of ozone, CO, and PM fine, which is a health concern and
contributes to visibility impairment. The standards will also reduce
personal exposure for people who operate or who work with or are
otherwise in close proximity to these engines and vehicles.
For the nonroad engines covered by this proposal, the Agency has
already established in several previous actions that they cause or
contribute to ozone or carbon monoxide pollution in more than one
nonattainment area. In three actions in 1996, 1999, and 2000, we made
separate determinations that each category of nonroad engines covered
by this proposal specifically contributes to ozone and CO
nonattainment, and to adverse health effects associated with ambient
concentrations of PM. These actions are summarized in Table II.A-1. In
addition, pursuant to Section 213(a)(4) of the Act, we are proposing to
find that nonroad engines, including construction equipment, farm
tractors, boats, planes, locomotives, marine engines, and recreational
vehicles (e.g., off-highway motorcycles, all-terrain-vehicles, and
snowmobiles), significantly contribute to regional haze, and that these
engines, particularly snowmobiles, are significant emitters of
pollutants that are known to impair visibility in federal Class I
areas. The discussion pertaining to this proposed finding is in Section
II.D.1, below.

Table II.A-1.--Summary of Nonroad Air Quality Findings
----------------------------------------------------------------------------------------------------------------
Source Date of finding Pollutants covered Emissions determined to contribute
----------------------------------------------------------------------------------------------------------------
CI Marine..................... December 29, 1999, 64 Ozone, PM............ HC+NO_X, PM, CO.
FR 73300.
Large SI...................... December 7, 2000, 65 Ozone, CO, PM........ HC+NO_X, CO, PM.
FR 76790.
Recreational Vehicles......... December 7, 2000, 65 Ozone, CO, PM........ HC+NO_X, CO, PM.
FR 76790.
----------------------------------------------------------------------------------------------------------------

B. What Are the Public Health and Welfare Effects Associated With
Emissions From Nonroad Engines Subject to the Proposed Standards?

The engines and vehicles that would be subject to the proposed
standards generate emissions of HC, CO, PM and air toxics that
contribute to ozone and CO nonattainment as well as adverse health
effects associated with ambient concentrations of PM and air toxics.
Elevated emissions from those recreational vehicles that operate in
national parks (e.g., snowmobiles) contribute to visibility impairment.
This section summarizes the general health effects of these substances.
National inventory estimates are set out in Section II.B, and estimates
of the expected impact of the proposed control programs are described
in Section IX. Interested readers are encouraged to refer to the Draft
Regulatory Support Document for this proposal for more in-depth
discussions.
1. Health and Welfare Effects Associated With Ground Level Ozone and
Its Precursors
Volatile organic compounds (VOC) and NO_X are precursors
in the photochemical reaction which forms tropospheric ozone. Ground-
level ozone, the main ingredient in smog, is formed by complex chemical
reactions of VOCs and NO_X in the presence of heat and
sunlight. Hydrocarbons (HC) are a large subset of VOC, and to reduce
mobile-source VOC levels we set maximum emissions limits for
hydrocarbon and particulate matter emissions.
A large body of evidence shows that ozone can cause harmful
respiratory effects including chest pain, coughing, and shortness of
breath, which affect people with compromised respiratory systems most
severely. When inhaled, ozone can cause acute respiratory problems;
aggravate asthma; cause significant temporary decreases in lung
function of 15 to over 20 percent in some healthy adults; cause
inflammation of lung tissue; produce changes in lung tissue and
structure; may increase hospital admissions and emergency room visits;
and impair the body's immune system defenses, making people more
susceptible to respiratory illnesses. Children and outdoor workers are
likely to be exposed to elevated ambient levels of ozone during
exercise and, therefore, are at a greater risk of experiencing adverse
health effects. Beyond its human health effects, ozone has been shown
to injure plants, which has the effect of reducing crop yields and
reducing productivity in forest ecosystems.
There is strong and convincing evidence that exposure to ozone is
associated with exacerbation of asthma-related symptoms. Increases in
ozone concentrations in the air have been associated with increases in
hospitalization for respiratory causes for individuals with asthma,
worsening of symptoms, decrements in lung function, and increased
medication use, and chronic exposure may cause permanent lung damage.
The risk of suffering these effects is particularly high for children
and for people with compromised respiratory systems.
Ground level ozone today remains a pervasive pollution problem in
the United States. In 1999, 90.8 million people (1990 census) lived in
31 areas designated nonattainment under the 1-hour ozone NAAQS.\73\
This sharp decline from the 101 nonattainment areas originally
identified under the Clean Air Act Amendments of 1990 demonstrates the
effectiveness of the last decade's worth of emission-control programs.
However, elevated ozone concentrations remain a serious public health
concern throughout the nation.
---------------------------------------------------------------------------

\73\ National Air Quality and Emissions Trends Report, 1999,
EPA, 2001, at Table A-19. This document is available at http://
www.epa.gov/airtrends/aqtrnd99/. The data from the Trends report are the
most recent EPA air quality data that have been quality assured. A
copy of this table can also be found in Docket No. A-2000-01,
Document No. II-A-64.
---------------------------------------------------------------------------

Over the last decade, declines in ozone levels were found mostly in
urban areas, where emissions are heavily influenced by controls on
mobile sources and their fuels. Twenty-three metropolitan areas have
realized a decline in ozone levels since 1989, but at the same time
ozone levels in 11 metropolitan areas with 7 million

[[Page 51105]]

people have increased.\74\ Regionally, California and the Northeast
have recorded significant reductions in peak ozone levels, while four
other regions (the Mid-Atlantic, the Southeast, the Central and Pacific
Northwest) have seen ozone levels increase.
---------------------------------------------------------------------------

\74\ National Air Quality and Emissions Trends Report, 1998,
March, 2000, at 28. This document is available at http://
www.epa.gov/airtrends/aqtrnd98/. Relevant pages of this report can be
found in Memorandum to Air Docket A-2000-01 from Jean Marie Revelt,
September 5, 2001, Document No. II-A-63.
---------------------------------------------------------------------------

The highest ambient concentrations are currently found in suburban
areas, consistent with downwind transport of emissions from urban
centers. Concentrations in rural areas have risen to the levels
previously found only in cities. Particularly relevant to this
proposal, ozone levels at 17 of our National Parks have increased, and
in 1998, ozone levels in two parks, Shenandoah National Park and the
Great Smoky Mountains National Park, were 30 to 40 percent higher than
the ozone NAAQS over part of the last decade.\75\
---------------------------------------------------------------------------

\75\ National Air Quality and Emissions Trends Report, 1998,
March, 2000, at 32. This document is available at http://
www.epa.gov/airtrends/aqtrnd98/. Relevant pages of this report can be
found in Memorandum to Air Docket A-2000-01 from Jean Marie Revelt,
September 5, 2001, Document No. II-A-63.
---------------------------------------------------------------------------

To estimate future ozone levels, we refer to the modeling performed
in conjunction with the final rule for our most recent heavy-duty
highway engine and fuel standards.\76\ We performed ozone air quality
modeling for the entire Eastern U.S. covering metropolitan areas from
Texas to the Northeast.\77\ This ozone air quality model was based upon
the same modeling system as was used in the Tier 2 air quality
analysis, with the addition of updated inventory estimates for 2007 and
2030. The results of this modeling were examined for those 37 areas in
the East for which EPA's modeling predicted exceedances in 2007, 2020,
and/or 2030 and the current 1-hour design values are above the standard
or within 10 percent of the standard. This photochemical ozone modeling
for 2020 predicts exceedances of the 1-hour ozone standard in 32 areas
with a total of 89 million people (1999 census) after accounting for
light- and heavy-duty on-highway control programs.\78\ We expect the
NO_X and HC control strategies contained in this proposal for
nonroad engines will further assist state efforts already underway to
attain and maintain the 1-hour ozone standard.
---------------------------------------------------------------------------

\76\ Additional information about this modeling can be found in
our Regulatory Impact Analysis: Heavy-Duty Engine and Vehicle
Standards and Highway Diesel Fuel Sulfur Control Requirements,
document EPA420-R-00-026, December 2000. Docket No. 1-2000-01,
Document No. II-A-13. This document is also available at
http://www.epa.gov/otaq/diesel.htm#documents.
\77\ We also performed ozone air quality modeling for the
western United States but, as described further in the air quality
technical support document, model predictions were well below
corresponding ambient concentrations for out heavy-duty engine
standards and fuel sulfur control rulemaking. Because of poor model
performance for this region of the country, the results of the
Western ozone modeling were not relied on for that rule.
\78\ Regulatory Impact Analysis: Heavy-Duty Engine and Vehicle
Standards and Highway Diesel Fuel Sulfur Control Requirements, US
EPA, EPA420-R-00-026, December 2000, at II-14, Table II.A-2. Docket
No. A-2000-01, Document Number II-A-13. This document is also
available at http://www.epa.gov/otaq/diesel.htm#documents.
---------------------------------------------------------------------------

In addition to the health effects described above, there exists a
large body of scientific literature that shows that harmful effects can
occur from sustained levels of ozone exposure much lower than 0.125
ppm.\79\ Studies of prolonged exposures, those lasting about 7 hours,
show health effects from prolonged and repeated exposures at moderate
levels of exertion to ozone concentrations as low as 0.08 ppm. The
health effects at these levels of exposure include transient pulmonary
function responses, transient respiratory symptoms, effects on exercise
performance, increased airway responsiveness, increased susceptibility
to respiratory infection, increased hospital and emergency room visits,
and transient pulmonary respiratory inflammation.
---------------------------------------------------------------------------

\79\ Additional information about these studies can be found in
Chapter 2 of ``Regulatory Impact Analysis: Heavy-Duty Engine and
Vehicle Standards and Highway Diesel Fuel Sulfur Control
Requirements,'' December 2000, EPA420-R-00-026. Docket No. A-2000-
01, Document Number II-A-13. This document is also available at
http://www.epa.gov/otaq/diesel.htm#documents.
---------------------------------------------------------------------------

Prolonged and repeated ozone concentrations at these levels are
common in areas throughout the country, and are found both in areas
that are exceeding, and areas that are not exceeding, the 1-hour ozone
standard. Areas with these high concentrations are more widespread than
those in nonattainment for that 1-hour ozone standard. Monitoring data
indicate that 333 counties in 33 states exceed these levels in 1997-
99.\80\ The Agency's most recent photochemical ozone modeling forecast
that 111 million people are predicted to live in areas that are at risk
of exceeding these moderate ozone levels for prolonged periods of time
in 2020 after accounting for expected inventory reductions due to
controls on light- and heavy-duty on-highway vehicles.\81\
---------------------------------------------------------------------------

\80\ A copy of these data can be found in Air Docket A-2000-01,
Document No. II-A-80.
\81\ Memorandum to Docket A-99-06 from Eric Ginsburg, EPA,
``Summary of Model-Adjusted Ambient Concentrations for Certain
Levels of Ground-Level Ozone over Prolonged Periods,'' November 22,
2000, at Table C, Control Scenario--2020 Populations in Eastern
Metropolitan Counties with Predicted Daily 8-Hour Ozone greater than
or equal to 0.080 ppm. Docket A-2000-01, Document Number II-B-13.
---------------------------------------------------------------------------

2. Health Effects Associated With Carbon Monoxide
Carbon monoxide (CO) is a colorless, odorless gas produced through
the incomplete combustion of carbon-based fuels. Carbon monoxide enters
the bloodstream through the lungs and reduces the delivery of oxygen to
the body's organs and tissues. The health threat from CO is most
serious for those who suffer from cardiovascular disease, particularly
those with angina or peripheral vascular disease. Healthy individuals
also are affected, but only at higher CO levels. Exposure to elevated
CO levels is associated with impairment of visual perception, work
capacity, manual dexterity, learning ability and performance of complex
tasks.
High concentrations of CO generally occur in areas with elevated
mobile-source emissions. Peak concentrations typically occur during the
colder months of the year when mobile-source CO emissions are greater
and nighttime inversion conditions are more frequent. This is due to
the enhanced stability in the atmospheric boundary layer, which
inhibits vertical mixing of emissions from the surface.
The current primary NAAQS for CO are 35 parts per million for the
one-hour average and 9 parts per million for the eight-hour average.
These values are not to be exceeded more than once per year. Air
quality carbon monoxide value is estimated using EPA guidance for
calculating design values. In 1999, 30.5 million people (1990 census)
lived in 17 areas designated nonattainment under the CO NAAQS.\82\
---------------------------------------------------------------------------

\82\ National Air Quality and Emissions Trends Report, 1999,
EPA, 2001, at Table A-19. This document is available at http://
www.epa.gov/airtrends/aqtrnd99/. The data from the Trends report are the
most recent EPA air quality data that have been quality assured. A
copy of this table can also be found in Docket No. A-2000-01,
Document No. II-A-64.
---------------------------------------------------------------------------

Snowmobiles, which have relatively high per engine CO emissions,
can be a significant source of ambient CO levels in CO nonattainment
areas. Several states that contain CO nonattainment areas also have
large populations of registered snowmobiles. This is shown in Table
II.B-1. A review of snowmobile trail maps indicates that snowmobiles
are used in these CO nonattainment

[[Page 51106]]

areas or in adjoining counties.\83\ These include the Mt. Spokane and
Riverside trails near the Spokane, Washington CO nonattainment area;
the Larimer trails near the Fort Collins, Colorado CO nonattainment
area; and the Hyatt Lake, Lake of the Woods, and Cold Springs trails
near the Klamath Falls and Medford, Oregon CO nonattainment area. There
are also trails in Missoula County, Montana that demonstrate snowmobile
use in the Missoula, Montana CO nonattainment area. While Colorado has
a large snowmobile population, the snowmobile trails are fairly distant
from the Colorado Springs CO nonattainment areas. EPA requests comment
on the volume and nature of snowmobile use in these and other CO
nonattainment areas. Of particular interest is information about the
number of trails in and around CO nonattainment areas, the magnitude of
snowmobile use on those trails, and the extent to which snowmobiles are
used off-trail.\84\
---------------------------------------------------------------------------

\83\ St. Paul, Minnesota was recently reclassified as being in
attainment but is still considered a maintenance area. There is also
a significant population of snowmobiles in Minnesota, with
snowmobile trails in Washington County.
\84\ The trail maps consulted for this proposal can be found in
Docket No. A-2000-01, Document No. II-A-65.

Table II.B-1.--Snowmobile Use in Selected CO Nonattainment Areas
----------------------------------------------------------------------------------------------------------------
1998 State
City and State CO nonattainment classification snowmobile
population \a\
----------------------------------------------------------------------------------------------------------------
Fairbanks, AK............................ Serious.............................................. 12,997
Spokane, WA.............................. Serious.............................................. 32,274
Colorado Springs, CO..................... Moderate............................................. 28,000
Fort Collins, CO......................... Moderate.............................................
Klamath Falls, OR........................ Moderate............................................. 13,426
Medford, OR.............................. Moderate.............................................
Missoula, MT............................. Moderate............................................. 14,361
----------------------------------------------------------------------------------------------------------------
\a\ Source: Letter from International Snowmobile Manufacturers Association to US-EPA, July 8, 1999, Docket A-
2000-01, Document No. II-G.

Exceedances of the 8-hour CO standard were recorded in three of
these seven CO nonattainment areas located in the northern portion of
the country over the five year period from 1994 to 1999: Fairbanks, AK;
Medford, OR; and Spokane, WA.\85\ Given the variability in CO ambient
concentrations due to weather patterns such as inversions, the absence
of recent exceedances for some of these nonattainment areas should not
be viewed as eliminating the need for further reductions to
consistently attain and maintain the standard. A review of CO monitor
data in Fairbanks from 1986 to 1995 shows that while median
concentrations have declined steadily, unusual combinations of weather
and emissions have resulted in elevated ambient CO concentrations well
above the 8-hour standard of 9 ppm. Specifically, a Fairbanks monitor
recorded average 8-hour ambient concentrations at 16 ppm in 1988,
around 9 ppm from 1990 to 1992, and then a steady increase in CO
ambient concentrations at 12, 14 and 16 ppm during some extreme cases
in 1993, 1994 and 1995, respectively.\86\
---------------------------------------------------------------------------

\85\ Technical Memorandum to Docket A-2000-01 from Drew Kodjak,
Attorney-Advisor, Office of Transportation and Air Quality, ``Air
Quality Information for Selected CO Nonattainment Areas,'' July 27,
2001, Docket Number A-2000-01, Document Number II-B-18.
\86\ Air Quality Criteria for Carbon Monoxide, US EPA, EPA 600/
P-99/001F, June 2000, at 3-38, Figure 3-32 (Federal Bldg, AIRS Site
020900002). Air Docket A-2000-01, Document Number II-A-29. This
document is also available at http://www.epa.gov/ncea/
coabstract.htm.
---------------------------------------------------------------------------

Nationally, significant progress has been made over the last decade
to reduce CO emissions and ambient CO concentrations. Total CO
emissions from all sources have decreased 16 percent from 1989 to 1998,
and ambient CO concentrations decreased by 39 percent. During that
time, while the mobile source CO contribution of the inventory remained
steady at about 77 percent, the highway portion decreased from 62
percent of total CO emissions to 56 percent while the nonroad portion
increased from 17 percent to 22 percent.\87\ Over the next decade, we
would expect there to be a minor decreasing trend from the highway
segment due primarily to the more stringent standards for certain
light-duty trucks (LDT2s).\88\ CO standards for passenger cars and
other light-duty trucks and heavy-duty vehicles did not change as a
result of other recent rulemakings). As described in Section II.C,
below, the engines subject to this rule currently account for about 7
percent of the mobile source CO inventory; this is expected to increase
to 10 percent by 2020 without the emission controls proposed in this
action.
---------------------------------------------------------------------------

\87\ National Air Quality and Emissions Trends Report, 1998,
March, 2000; this document is available at http://www.epa.gov/airtrends/
aqtrnd98/. National Air Pollutant Emission Trends, 1900-1998 (EPA-
454/R-00-002), March, 2000. These documents are available at Docket
No. A-2000-01, Document No. II-A-72. See also Air Quality Criteria
for Carbon Monoxide, US EPA, EPA 600/P-99/001F, June 2000, at 3-10.
Air Docket A-2000-01, Document Number II-A-29. This document is also
available at http://www.epa.gov/ncea/coabstract.htm.
\88\ LDT2s are light light-duty trucks greater than 3750 lbs.
loaded vehicle weight, up through 6000 gross vehicle weight rating.
---------------------------------------------------------------------------

The state of Alaska recently submitted draft CO attainment SIPs to
the Agency for the Fairbanks CO nonattainment area. Fairbanks is
located in a mountain valley with a much higher potential for air
stagnation than cities within the contiguous United States. Nocturnal
inversions that give rise to elevated CO concentrations can persist 24-
hours a day due to the low solar elevation, particularly in December
and January. These inversions typically last from 2 to 4 days (Bradley
et al., 1992), and thus inversions may continue during hours of maximum
CO emissions from mobile sources. Despite the fact that snowmobiles are
largely banned in CO nonattainment areas by the state, the state
estimated that snowmobiles contributed 0.3 tons/day in 1995 to
Fairbanks' CO nonattainment area or 1.2 percent of a total inventory of
23.3 tons per day in 2001.\89\ While Fairbanks has made significant
progress in reducing ambient CO concentrations, existing climate
conditions make achieving and maintaining attainment challenging.
Fairbanks failed to attain the CO NAAQS by the applicable deadline of

[[Page 51107]]

December 21, 2000, and EPA approved a one-year extension in May of
2001.\90\
---------------------------------------------------------------------------

\89\ Draft Anchorage Carbon Monoxide Emission Inventory and Year
2000 Attainment Projections, Air Quality Program, May 2001, Docket
Number A-2000-01, Document II-A-40; Draft Fairbanks 1995-2001 Carbon
Monoxide Emissions Inventory, June 1, 2001, Docket Number A-2000-01,
Document II-A-39.
\90\ 66 FR 28836, May 25, 2001. Clean Air Act Promulgation of
Attainment Date Extension for the Fairbanks North Star Borough
Carbon Monoxide Nonattainment Area, AK, Direct Final Rule.
---------------------------------------------------------------------------

In addition to the health effects that can result from exposure to
carbon monoxide, this pollutant also can contribute to ground level
ozone formation.\91\ Recent studies in atmospheric chemistry in urban
environments suggest CO can react with hydrogen-containing radicals,
leaving fewer of these to combine with non-methane hydrocarbons and
thus leading to increased levels of ozone. Few analyses have been
performed that estimate these effects, but a study of an ozone episode
in Atlanta, GA in 1988 found that CO accounted for about 17.5 percent
of the ozone formed (compared to 82.5 percent for volatile organic
compounds). While different cities may have different results, the
effects of CO emissions on ground level ozone are not insignificant.
The engines that are the subject of the proposed standards are
contributors to these effects in urban areas, particularly because
their per engine emissions are so high. For example, CO emissions from
an off-highway motorcycle are high relative to a passenger car, (32 g/
mi compared to 4.2 g/mi). The CO controls contained in this proposal
will further assist state efforts already underway to attain and
maintain the CO NAAQS.
---------------------------------------------------------------------------

\91\ U.S. EPA, Air Quality Criteria for Carbon Monoxide, EPA
600/P-99.001F, June 2000, Section 3.2.3. Air Docket A-2000-01,
Document Number II-A-29. This document is also available at http://
www.epa.gov/ncea/coabstract.htm.
---------------------------------------------------------------------------

3. Health and Welfare Effects Associated With Particulate Matter
Nonroad engines and vehicles that would be subject to the proposed
standards contribute to ambient particulate matter (PM) levels in two
ways. First, they contribute through direct emissions of particulate
matter. Second, they contribute to indirect formation of PM through
their emissions of organic carbon, especially HC. Organic carbon
accounts for between 27 and 36 percent of fine particle mass depending
on the area of the country.
Particulate matter represents a broad class of chemically and
physically diverse substances. It can be principally characterized as
discrete particles that exist in the condensed (liquid or solid) phase
spanning several orders of magnitude in size. All particles equal to
and less than 10 microns are called PM₁₀. Fine particles can
be generally defined as those particles with an aerodynamic diameter of
2.5 microns or less (also known as PM_2.5), and coarse
fraction particles are those particles with an aerodynamic diameter
greater than 2.5 microns, but equal to or less than a nominal 10
microns.
Particulate matter, like ozone, has been linked to a range of
serious respiratory health problems. Scientific studies suggest a
likely causal role of ambient particulate matter (which is attributable
to several sources including mobile sources) in contributing to a
series of health effects.\92\ The key health effects categories
associated with ambient particulate matter include premature mortality,
aggravation of respiratory and cardiovascular disease (as indicated by
increased hospital admissions and emergency room visits, school
absences, work loss days, and restricted activity days), aggravated
asthma, acute respiratory symptoms, including aggravated coughing and
difficult or painful breathing, chronic bronchitis, and decreased lung
function that can be experienced as shortness of breath. Observable
human noncancer health effects associated with exposure to diesel PM
include some of the same health effects reported for ambient PM such as
respiratory symptoms (cough, labored breathing, chest tightness,
wheezing), and chronic respiratory disease (cough, phlegm, chronic
bronchitis and suggestive evidence for decreases in pulmonary
function). Symptoms of immunological effects such as wheezing and
increased allergenicity are also seen. Exposure to fine particles is
closely associated with such health effects as premature mortality or
hospital admissions for cardiopulmonary disease.
---------------------------------------------------------------------------

\92\ EPA (1996) Review of the National Ambient Air Quality
Standards for Particulate Matter: Policy Assessment of Scientific
and Technical Information OAQPS Staff Paper. EPA-452/R-96-013.
Docket Number A-99-06, Documents Nos. II-A-18, 19, 20, and 23. The
particulate matter air quality criteria documents are also available
at http://www.epa.gov/ncea/partmatt.htm.
---------------------------------------------------------------------------

PM also causes adverse impacts to the environment. Fine PM is the
major cause of reduced visibility in parts of the United States,
including many of our national parks. Other environmental impacts occur
when particles deposit onto soils, plants, water or materials. For
example, particles containing nitrogen and sulphur that deposit on to
land or water bodies may change the nutrient balance and acidity of
those environments. Finally, PM causes soiling and erosion damage to
materials, including culturally important objects such as carved
monuments and statues. It promotes and accelerates the corrosion of
metals, degrades paints, and deteriorates building materials such as
concrete and limestone.
The NAAQS for PM₁₀ were established in 1987. According
to these standards, the short term (24-hour) standard of 150
µg/m3 is not to be exceeded more than once per year
on average over three years. The long-term standard specifies an
expected annual arithmetic mean not to exceed 50 µg/
m3 over three years. The most recent PM₁₀
monitoring data indicate that 14 designated PM₁₀
nonattainment areas with a projected population of 23 million violated
the PM₁₀ NAAQS in the period 1997-99. In addition, there are
25 unclassifiable areas that have recently recorded ambient
concentrations of PM₁₀ above the PM₁₀ NAAQS.\93\
---------------------------------------------------------------------------

\93\ EPA adopted a policy in 1996 that allows areas with
PM₁₀ exceedances that are attributable to natural events
to retain their designation as unclassifiable if the State is taking
all reasonable measures to safeguard public health regardless of the
sources of PM₁₀ emissions.
---------------------------------------------------------------------------

Current 1999 PM_2.5 monitored values, which cover about a
third of the nation's counties, indicate that at least 40 million
people live in areas where long-term ambient fine particulate matter
levels are at or above 16 µg/m3 (37 percent of the
population in the areas with monitors).\94\ This 16 µg/
m3 threshold is the low end of the range of long term
average PM_2.5 concentrations in cities where statistically
significant associations were found with serious health effects,
including premature mortality.\95\ To estimate the number of people who
live in areas where long-term ambient fine particulate matter levels
are at or above 16 µg/m3 but for which there are no
monitors, we can use modeling. According to our national modeled
predictions, there were a total of 76 million people (1996 population)
living in areas with modeled annual average PM_2.5
concentrations at or above 16 µg/m3 (29 percent of
the population).\96\
---------------------------------------------------------------------------

\94\ Memorandum to Docket A-99-06 from Eric O. Ginsburg, Senior
Program Advisor, ``Summary of 1999 Ambient Concentrations of Fine
Particulate Matter,'' November 15, 2000. Air Docket A-2000-01,
Document No. II-B-12.
\95\ EPA (1996) Review of the National Ambient Air Quality
Standards for Particulate Matter: Policy Assessment of Scientific
and Technical Information OAQPS Staff Paper. EPA-452/R-96-013.
Docket Number A-99-06, Documents Nos. II-A-18, 19, 20, and 23. The
particulate matter air quality criteria documents are also available
at http://www.epa.gov/ncea/partmatt.htm.
\96\ Memorandum to Docket A-99-06 from Eric O. Ginsburg, Senior
Program Advisor, ``Summary of Absolute Modeled and Model-Adjusted
Estimates of Fine Particulate Matter for Selected Years,'' December
6, 2000. Air Docket A-2000-01, Document No. II-B-14.
---------------------------------------------------------------------------

To estimate future PM_2.5 levels, we refer to the
modeling performed in

[[Page 51108]]

conjunction with the final rule for our most recent heavy-duty highway
engine and fuel standards, using EPA's Regulatory Model System for
Aerosols and Deposition (REMSAD).\97\ The most appropriate method of
making these projections relies on the model to predict changes between
current and future states. Thus, we have estimated future conditions
only for the areas with current PM_2.5 monitored data (which
cover about a third of the nation's counties). For these counties,
REMSAD predicts the current level of 37 percent of the population
living in areas where fine PM levels are at or above 16 µg/
m3 to increase to 49 percent in 2030.\98\
---------------------------------------------------------------------------

\97\ Additional information about the Regulatory Model System
for Aerosols and Deposition (REMSAD) and our modeling protocols can
be found in our Regulatory Impact Analysis: Heavy-Duty Engine and
Vehicle Standards and Highway Diesel Fuel Sulfur Control
Requirements, document EPA420-R-00-026, December 2000. Docket No. A-
2000-01, Document No. A-II-13. This document is also available at
http://www.epa.gov/otaq/diesel.htm#documents.
\98\ Technical Memorandum, EPA Air Docket A-99-06, Eric O.
Ginsburg, Senior Program Advisor, Emissions Monitoring and Analysis
Division, OAQPS, Summary of Absolute Modeled and Model-Adjusted
Estimates of Fine Particulate Matter for Selected Years, December 6,
2000, Table P-2. Docket Number 2000-01, Document Number II-B-14.
---------------------------------------------------------------------------

Emissions of HCs from snowmobiles contribute to secondary formation
of fine particulate matter which can cause a variety of adverse health
and welfare effects, including visibility impairment discussed in
Section II.D.1(b) below. For 20 counties across nine states, snowmobile
trails are found within or near counties that registered ambient PM 2.5
concentrations at or above 15 µg/m3, the level of
the revised national ambient air quality standard for fine
particles.\99\ Fine particles may remain suspended for days or weeks
and travel hundreds to thousands of kilometers, and thus fine particles
emitted or created in one county may contribute to ambient
concentrations in a neighboring county.\100\ These counties are listed
in Table II.B-2. To obtain the information about snowmobile trails
contained in Table II.B-2, we consulted snowmobile trail maps that were
supplied by various states.\101\
---------------------------------------------------------------------------

\99\ Memo to file from Terence Fitz-Simons, OAQPS, Scott
Mathias, OAQPS, Mike Rizzo, Region 5, ``Analyses of 1999 PM Data for
the PM NAAQS Review,'' November 17, 2000, with attachment B, 1999
PM2.5 Annual Mean and 98th Percentile 24-Hour Average
Concentrations. Docket No. A-2000-01, Document No. II-B-17.
\100\ Review of the National Ambient Air Quality Standards for
Particulate Matter: Policy Assessment for Scientific and Technical
Information, OAQPS Staff Paper, EPA-452/R-96-013, July, 1996, at IV-
7.
\101\ The trail maps consulted for this proposal can be found in
Docket No. A-2000-01, Document No. II-A-65.

Table II.B-2.--Counties With Annual PM_2.5 Levels Above 16 µg/m\3\ and Snowmobile Trails
----------------------------------------------------------------------------------------------------------------
State and PM_2.5 exceedance county County with snowmobile trails Proximity to PM_2.5 exceedance county
----------------------------------------------------------------------------------------------------------------
Ohio:
Mahoning............................ Mahoning.....................
Trumbull............................ Trumbull.....................
Summit.............................. Summit.......................
Montgomery.......................... Montgomery...................
Portage............................. Portage......................
Franklin............................ Delaware..................... Borders North.
Marshall/Ohio (WV).................. Belmont...................... Borders West.
Montana............................... Lincoln...................... Lincoln
California:
Tulane.............................. Tulane.......................
Butte............................... Butte........................
Fresno.............................. Fresno.......................
Kern................................ Kern.........................
Minnesota:
Washington.......................... Washington...................
Wright.............................. Wright.......................
Wisconsin:
Waukesha............................ Waukesha.....................
Milwaukee........................... Milwaukee....................
Oregon:
Jackson............................. Douglas...................... Borders NNE.
Klamath............................. Douglas...................... Borders North.
Pennsylvania: Washington.............. Layette...................... Borders East.
Somerset.....................
Illinois: Rock Island................. Rock Island
Henry........................ Borders East.
Iowa: Rock Island (IL)................ Dubuque...................... Borders West.
----------------------------------------------------------------------------------------------------------------

We expect the PM control strategies contained in this proposal
would further assist state efforts already underway to attain and
maintain the PM NAAQS.
4. Health Effects Associated With Air Toxics
In addition to the human health and welfare impacts described
above, emissions from the engines covered by this proposal also contain
several other substances that are known or suspected human or animal
carcinogens, or have serious noncancer health effects. These include
benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and acrolein. The
health effects of these air toxics are described in more detail in
Chapter 1 of the Draft Regulatory Support Document for this rule.
Additional information can also be found in the Technical Support

[[Page 51109]]

Document for our final Mobile Source Air Toxics rule.102
---------------------------------------------------------------------------

\102\ See our Mobile Source Air Toxics final rulemaking, 66 FR
17230, March 29, 2001, and the Technical Support Document for that
rulemaking. Docket No. A-2000-01, Documents Nos. II-A-42 and II-A-
30.
---------------------------------------------------------------------------

The hydrocarbon controls contained in this proposal are expected to
reduce exposure to air toxics and therefore may help reduce the impact
of these engines on cancer and noncancer health effects.

C. What Is the Inventory Contribution From the Nonroad Engines and
Vehicles That Would Be Subject to This Proposal?

The contribution of emissions from the nonroad engines and vehicles
that would be subject to the proposed standards to the national
inventories of pollutants that are associated with the health and
public welfare effects described in Section II.B are considerable. To
estimate nonroad engine and vehicle emission contributions, we used the
latest version of our NONROAD emissions model. This model computes
nationwide, state, and county emission levels for a wide variety of
nonroad engines, and uses information on emission rates, operating
data, and population to determine annual emission levels of various
pollutants. A more detailed description of the model and our estimation
methodology can be found in the Chapter 6 of the Draft Regulatory
Support Document.
Baseline emission inventory estimates for the year 2000 for the
categories of engines and vehicles covered by this proposal are
summarized in Table II.C-1. This table shows the relative contributions
of the different mobile-source categories to the overall national
mobile-source inventory. Of the total emissions from mobile sources,
the categories of engines and vehicles covered by this proposal
contribute about 13 percent, 3 percent, 6 percent, and 1 percent of HC,
NO_X, CO, and PM emissions, respectively, in the year 2000.
The results for industrial SI engines indicate they contribute
approximately 3 percent to HC, NO_X, and CO emissions from
mobile sources. The results for land-based recreational engines reflect
the impact of the significantly different emissions characteristics of
two-stroke engines. These engines are estimated to contribute 10
percent of HC emissions and 3 percent of CO from mobile sources.
Recreational CI marine contribute less than 1 percent to NO_X
mobile source inventories. When only nonroad emissions are considered,
the engines and vehicles that would be subject to the proposed
standards would account for a larger share.
Our draft emission projections for 2020 for the nonroad engines and
vehicles subject to this proposal show that emissions from these
categories are expected to increase over time if left uncontrolled. The
projections for 2020 are summarized in Table II.C-2 and indicate that
the categories of engines and vehicles covered by this proposal are
expected to contribute 33 percent, 9 percent, 9 percent, and 2 percent
of HC, NO_X, CO, and PM emissions in the year 2020.
Population growth and the effects of other regulatory control programs
are factored into these projections. The relative importance of
uncontrolled nonroad engines is higher than the projections for 2000
because there are already emission control programs in place for the
other categories of mobile sources which are expected to reduce their
emission levels. The effectiveness of all control programs is offset by
the anticipated growth in engine populations.

Table II.C-1.--Modeled Annual Emission Levels for Mobile-Source Categories in 2000
[Thousand short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
NO_X HC CO PM
---------------------------------------------------------------------------------------
Category Percent Percent Percent Percent
Tons of mobile Tons of mobile Tons of mobile Tons of mobile
source source source source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total for engines subject to proposed standards................. 343 2.6 985 12.9 4,870 6.3 8.3 1.2
=======================================================================================
Highway Motorcycles............................................. 8 0.1 84 1.1 329 0.4 0.4 0.1
Nonroad Industrial SI > 19 kW................................... 306 2.3 247 3.2 2,294 3.0 1.6 0.2
Recreational SI................................................. 13 0.1 737 9.7 2,572 3.3 5.7 0.8
Recreation Marine CI............................................ 24 0.2 1 0.0 4 0.0 1 0.1
Marine SI Evap.................................................. 0 0.0 89 1.2 0 0.0 0 0.0
Marine SI Exhaust............................................... 32 0.2 708 9.3 2,144 2.8 38 5.4
Nonroad SI 19 kW............................................... 106 0.8 1,460 19.1 18,359 23.6 50 7.2
Nonroad CI...................................................... 2,625 19.5 316 4.1 1,217 1.6 253 36.2
Commercial Marine CI............................................ 977 7.3 30 0.4 129 0.2 41 5.9
Locomotive...................................................... 1,192 8.9 47 0.6 119 0.2 30 4.3
---------------------------------------------------------------------------------------
Total Nonroad................................................... 5,275 39 3,635 48 26,838 35 420 60
Total Highway................................................... 7,981 59 3,811 50 49,811 64 240 34
Aircraft........................................................ 178 1 183 2 1,017 1 39 6
---------------------------------------------------------------------------------------
Total Mobile Sources............................................ 13,434 100 7,629 100 77,666 100 699 100
=======================================================================================
Total Man-Made Sources.......................................... 24,538 ......... 18,575 ......... 99,745 ......... 3,095 .........
=======================================================================================
Mobile Source percent of Total Man-Made Sources................. 55 ......... 41 ......... 78 ......... 23 .........
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 51110]]

Table II.C-2.--Modeled Annual Emission Levels for Mobile-Source Categories in 2020
[Thousand short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
NO_X HC CO PM
---------------------------------------------------------------------------------------
Category Percent Percent Percent Percent
Tons of mobile Tons of mobile Tons of mobile Tons of mobile
source source source source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total for engines subject to proposed standards................. 552 8.9 2,055 33.4 8,404 9.4 11.4 1.8
=======================================================================================
Highway Motorcyles.............................................. 14 0.2 144 2.3 569 0.6 0.8 0.1
Nonroad Industrial SI > 19 kW................................... 486 7.8 348 5.7 2,991 3.3 2.4 0.4
Recreational SI................................................. 27 0.4 1,706 27.7 5,407 3.3 7.5 1.2
Recreation Marine CI............................................ 39 0.6 1 0.0 6 0.0 1.5 0.2
Marine SI Evap.................................................. 0 0.0 102 1.4 0 0.0 0 0.0
Marine SI Exhaust............................................... 58 0.9 284 4.6 1,985 2.2 28 4.4
Nonroad SI 19 kW............................................... 106 1.7 986 16.0 27,352 30.5 77 12.2
Nonroad CI...................................................... 1,791 28.8 142 2.3 1,462 1.6 261 41.3
Commercial Marine CI............................................ 819 13.2 35 0.6 160 0.2 46 7.3
Locomotive...................................................... 611 9.8 35 0.6 119 0.1 21 3.3
---------------------------------------------------------------------------------------
Total Nonroad................................................... 3,937 63 3,639 59 39,482 44 444 70
Total Highway................................................... 2,050 33 2,278 37 48,903 54 145 23
Aircraft........................................................ 232 4 238 4 1,387 2 43 7
---------------------------------------------------------------------------------------
Total Mobile Sources............................................ 6,219 100 6,155 100 89,772 100 632 100
=======================================================================================
Total Man-Made Sources.......................................... 16,195 ......... 16,215 ......... 113,440 ......... 3,016 .........
=======================================================================================
Mobile Source percent of Total Man-Made Sources................. 38 ......... 38 ......... 79 ......... 21 .........
--------------------------------------------------------------------------------------------------------------------------------------------------------

D. Regional and Local-Scale Public Health and Welfare Effects

The previous section describes national-scale adverse public health
effects associated with the nonroad engines and vehicles covered by
this proposal. This section describes significant adverse health and
welfare effects arising from the usage patterns of snowmobiles, Large
SI engines, and gasoline marine engines on the regional and local
scale. Studies suggest that emissions from these engines can be
concentrated in specific areas, leading to elevated ambient
concentrations of particular pollutants and associated elevated
personal exposures to operators and by-standers. Recreational vehicles,
and particularly snowmobiles, are typically operating in rural areas
such as national parks and wilderness areas, and emissions from these
vehicles contribute to ambient particulate matter which is a leading
component of visibility impairment.
1. Health and Welfare Effects Related to Snowmobiles
In this section, we describe more localized human health and
welfare effects associated with snowmobile emissions: visibility
impairment and personal exposure to air toxics and CO. We describe the
contribution of snowmobile HC emissions to secondary formation of fine
particles, which are the leading component of visibility impairment and
adverse health effects related to ambient PM2.5 concentrations greater
than 16 ug/m3. We also discuss personal exposure to CO emissions and
air toxics. Gaseous air toxics are components of hydrocarbons, and CO
personal exposure measurements suggest that snowmobile riders and
bystanders are exposed to unhealthy levels of gaseous air toxics (e.g.,
benzene) and CO.
a. Nonroad Engines and Regional Haze. The Clean Air Act established
special goals for improving visibility in many national parks,
wilderness areas, and international parks. In the 1977 amendments to
the Clean Air Act, Congress set as a national goal for visibility the
``prevention of any future, and the remedying of any existing,
impairment of visibility in mandatory class I Federal areas which
impairment results from manmade air pollution'' (CAA section
169A(a)(1)). The Amendments called for EPA to issue regulations
requiring States to develop implementation plans that assure
``reasonable progress'' toward meeting the national goal (CAA Section
169A(a)(4)). EPA issued regulations in 1980 to address visibility
problems that are ``reasonably attributable'' to a single source or
small group of sources, but deferred action on regulations related to
regional haze, a type of visibility impairment that is caused by the
emission of air pollutants by numerous emission sources located across
a broad geographic region. At that time, EPA acknowledged that the
regulations were only the first phase for addressing visibility
impairment. Regulations dealing with regional haze were deferred until
improved techniques were developed for monitoring, for air quality
modeling, and for understanding the specific pollutants contributing to
regional haze.
In the 1990 Clean Air Act amendments, Congress provided additional
emphasis on regional haze issues (see CAA section 169B). In 1999 EPA
finalized a rule that calls for States to establish goals and emission
reduction strategies for improving visibility in all 156 mandatory
Class I national parks and wilderness areas. In that rule, EPA also
encouraged the States to work together in developing and implementing
their air quality plans. The regional haze program is designed to
improve visibility and air quality in our most treasured natural areas.
At the same time, control strategies designed to improve visibility in
the national parks and wilderness areas will improve visibility over
broad geographic areas.
Regional haze is caused by the emission from numerous sources
located over a wide geographic area. Such sources include, but are not
limited to, major and minor stationary sources, mobile sources, and
area sources. Visibility impairment is caused by pollutants (mostly
fine particles and precursor gases) directly emitted to the

[[Page 51111]]

atmosphere by several activities (such as electric power generation,
various industry and manufacturing processes, truck and auto emissions,
construction activities, etc.). These gases and particles scatter and
absorb light, removing it from the sight path and creating a hazy
condition.
Some fine particles are formed when gases emitted to the air form
particles as they are carried downwind (examples include sulfates,
formed from sulfur dioxide, and nitrates, formed from nitrogen oxides).
These activities generally span broad geographic areas and fine
particles can be transported great distances, sometimes hundreds or
thousands of miles. Consequently, visibility impairment is a national
problem. Without the effects of pollution a natural visual range is
approximately 140 miles in the West and 90 miles in the East. However,
fine particles have significantly reduced the range that people can see
and in the West the current range is 33-90 miles and in the East it is
only 14 to 24 miles.
Because of evidence that fine particles are frequently transported
hundreds of miles, all 50 states, including those that do not have
Class I areas, will have to participate in planning, analysis and, in
many cases, emission control programs under the regional haze
regulations. Even though a given State may not have any Class I areas,
pollution that occurs in that State may contribute to impairment in
Class I areas elsewhere. The rule encourages states to work together to
determine whether or how much emissions from sources in a given state
affect visibility in a downwind Class I area.
The regional haze program calls for states to establish goals for
improving visibility in national parks and wilderness areas to improve
visibility on the haziest 20 percent of days and to ensure that no
degradation occurs on the clearest 20 percent of days. The rule
requires states to develop long-term strategies including enforceable
measures designed to meet reasonable progress goals. Under the regional
haze program, States can take credit for improvements in air quality
achieved as a result of other Clean Air Act programs, including
national mobile-source programs.
Nonroad engines (including construction equipment, farm tractors,
boats, planes, locomotives, recreational vehicles, and marine engines)
contribute significantly to regional haze. This is because there are
nonroad engines in all of the states, and their emissions contain
precursors of fine PM and organic carbon that are transported and
contribute to the formation of regional haze throughout the country and
in Class I areas specifically. As illustrated in Table II.D-1, nonroad
engines are expected to contribute 15 percent of national VOC
emissions, 23 percent of national NO_X emissions, 6 percent
of national SOx emissions, and 14 percent of national PM10 emissions.
Snowmobiles alone are estimated to emit 208,926 tons of total
hydrocarbons (THC), 1,461 tons of NO_X, 2,145 tons of SOx,
and 5,082 tons of PM in 2007.

Table II.D-1.--National Emissions of Various Pollutants--2007
[Thousands short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
VOC NO_X SO_X PM₁₀
Source -----------------------------------------------------------------------------------------------
Tons Percent Tons Percent Tons Percent Tons Percent
--------------------------------------------------------------------------------------------------------------------------------------------------------
Heavy-Duty Highway...................................... 413 3 2,969 14 24 0 115 4
Light-Duty Highway...................................... 2,596 18 2,948 14 24 0 82 3
Nonroad................................................. 2,115 15 4,710 23 1,027 6 407 14
Electric General........................................ 35 0 4,254 21 10,780 63 328 12
Point................................................... 1,639 11 3,147 15 3,796 22 1,007 36
Area.................................................... 7,466 52 2,487 12 1,368 8 874 31
------------ ------------ ------------ ------------
Total............................................. 14,265 20,516 17,019 2,814
--------------------------------------------------------------------------------------------------------------------------------------------------------

b. Snowmobiles and Visibility Impairment. As noted above, EPA
issued regulations in 1980 to address Class I area visibility
impairment that is ``reasonably attributable'' to a single source or
small group of sources. In 40 CFR Part 51.301 of the visibility
regulations, visibility impairment is defined as ``any humanly
perceptible change in visibility (light extinction, visual range,
contrast, coloration) from that which would have existed under natural
conditions.'' States are required to develop implementation plans that
include long-term strategies for improving visibility in each class I
area. The long-term strategies under the 1980 regulations should
consist of measures to reduce impacts from local sources and groups of
sources that contribute to poor air quality days in the class I area.
Types of impairment covered by these regulations includes layered hazes
and visible plumes. While these kinds of visibility impairment can be
caused by the same pollutants and processes as those that cause
regional haze, they generally are attributed to a smaller number of
sources located across a smaller area. The Clean Air Act and associated
regulations call for protection of visibility impairment in class I
areas from localized impacts as well as broader impacts associated with
regional haze.
Visibility and particle monitoring data are available for 8 Class I
areas where snowmobiles are commonly used. These are: Acadia, Boundary
Waters, Denali, Mount Rainier, Rocky Mountain, Sequoia and Kings
Canyon, Voyageurs, and Yellowstone.\103\ Visibility and fine particle
data for these parks are set out in Table II.D-2. This table shows the
number of monitored days in the winter that fell within the 20-percent
haziest days for each of these eight parks. Monitors collect data two
days a week for a total of about 104 days of monitored values. Thus,
for a particular site, a maximum of 21 worst possible days of these 104
days with monitored values constitute the set of 20-percent haziest
days during a year which are tracked as the primary focus of regulatory
efforts.\104\ With the exception of Denali in Alaska, we defined the
snowmobile season as January 1 through March 15 and December 15 through
December 31 of the same calendar year, consistent with the methodology
used in the Regional Haze Rule, which is calendar-year based. For
Denali in

[[Page 51112]]

Alaska, the snowmobile season is October 1 to April 30. The Agency
would be interested in comments from the public on the start and end
dates for the typical snowmobile season at each of these national
parks.
---------------------------------------------------------------------------

\103\ No data were available at five additional parks where
snowmobiles are also commonly used: Black Canyon of the Gunnison,
CO, Grant Teton, WY, Northern Cascades, WA, Theodore Roosevelt, ND,
and Zion, UT.
\104\ Letter from Debra C. Miller, Data Analyst, National Park
Service, to Drew Kodjak, August 22, 2001. Docket No. A-2000-01,
Document Number. II-B-28.

Table II.D-2.--Winter Days That Fall Within the 20 Percent Haziest Days at National Parks Used by Snowmobiles
----------------------------------------------------------------------------------------------------------------
Number of sampled wintertime days
within 20 percent haziest days
NPS Unit State(s) (maximum of 21 sampled days)
---------------------------------------
1996 1997 1998 1999
----------------------------------------------------------------------------------------------------------------
Acadia NP........................ ME................................... 4 4 2 1
Denali NP and Preserve........... AK................................... 10 10 12 9
Mount Rainier NP................. WA................................... 1 3 1 1
Rocky Mountain NP................ CO................................... 2 1 2 1
Sequoia and Kings Canyon NP...... CA................................... 4 9 1 8
Voyageurs NP (1989-1992)......... MN................................... 1989 1990 1991 1992
3 4 6 8
--Boundary Waters USFS Wilderness MN................................... 2 5 1 5
Area (close to Voyaguers with
recent data).
Yellowstone NP................... ID, MT, WY........................... 0 2 0 0
----------------------------------------------------------------------------------------------------------------
Source: Letter from Debra C. Miller, Data Analyst, National Park Service, to Drew Kodjak, August 22, 2001.
Docket No. A-2000-01, Document Number. II-B-28.

The information presented in Table II.D-2 shows that visibility
data support a conclusion that there are at least eight Class I Areas
(7 in National Parks and one in a Wilderness Area) frequented by
snowmobiles with one or more wintertime days within the 20-percent
haziest days of the year. For example, Rocky Mountain National Park in
Colorado was frequented by about 27,000 snowmobiles during the 1998-
1999 winter. Of the monitored days characterized as within the 20-
percent haziest monitored days, two (2) of those days occurred during
the wintertime when snowmobile emissions such as hydrocarbons
contributed to visibility impairment. According to the National Park
Service, ``[s]ignificant differences in haziness occur at all eight
sites between the averages of the clearest and haziest days.
Differences in mean standard visual range on the clearest and haziest
days fall in the approximate range of 115-170 km.'' \105\
---------------------------------------------------------------------------

\105\ Letter from Debra C. Miller, Data Analyst, National Park
Service, to Drew Kodjak, August 22, 2001. Docket No. A-2000-01,
Document Number. II-B-28.
---------------------------------------------------------------------------

Ambient concentrations of fine particles are the primary pollutant
responsible for visibility impairment. Five pollutants are largely
responsible for the chemical composition of fine particles: sulfates,
nitrates, organic carbon particles, elemental carbon, and crustal
material. Hydrocarbon emissions from automobiles, trucks, snowmobiles,
and other industrial processes are common sources of organic carbon.
The organic carbon fraction of fine particles ranges from 47 percent in
Western areas such as Denali National Park, to 28 percent in Rocky
Mountain National Park, to 13 percent in Acadia National Park.\106\
---------------------------------------------------------------------------

\106\ Letter from Debra C. Miller, Data Analyst, National Park
Service, to Drew Kodjak, August 22, 2001. Docket No. A-2000-01,
Document Number. II-B-28.
---------------------------------------------------------------------------

The contribution of snowmobiles to elemental carbon and nitrates is
small. Their contribution to sulfates is a function of fuel sulfur and
is small and will decrease even more as the sulfur content of their
fuel decreases due to our recently finalized fuel sulfur requirements.
In the winter months, however, hydrocarbon emissions from snowmobiles
can be significant, as indicated in Table II.D-3, and these HC
emissions can contribute significantly to the organic carbon fraction
of fine particles which are largely responsible for visibility
impairment. This is because they are typically powered by two-stroke
engines that emit large amounts of hydrocarbons. In Yellowstone, a park
with high snowmobile usage during the winter months, snowmobile
hydrocarbon emissions can exceed 500 tons per year, as much as several
large stationary sources. Other parks with less snowmobile traffic are
less impacted by these hydrocarbon emissions.\107\
---------------------------------------------------------------------------

\107\ Technical Memorandum, Aaron Worstell, Environmental
Engineer, National Park Service, Air Resources Division, Denver,
Colorado, particularly Table 1. Docket No. A-2000-01, Document
Number II-G-178.
---------------------------------------------------------------------------

Table II.D-3 shows modeled tons of four pollutants during the
winter season in five Class I national parks for which we have
estimates of snowmobile use. The national park areas outside of Denali
in Alaska are open to snowmobile operation in accordance with special
regulations (36 CFR Part 7). Denali National Park permits snowmobile
operation by local rural residents engaged in subsistence uses (36 CFR
Part 13). Emission calculations are based on an assumed 2 hours of use
per snowmobile visit at 16 hp with the exception of Yellowstone where 4
hours of use at 16 hp was assumed. The emission factors used to
estimate these emissions are identical to those used by the NONROAD
model. Two-stroke snowmobile emission factors are: 111 g/hp-hr HC, 296
g/hp-hr CO, 0.86 g/hp-hr NO_X, and 2.7 g/hp-hr PM. These
emission factors are based on several engine tests performed by the
International Snowmobile Manufacturers Association (ISMA) and the
Southwest Research Institute (SwRI). These emission factors are still
under review, and the emissions estimates may change pending the
outcome of that review.

[[Page 51113]]

Table II.D-3.--Winter Season Snowmobile Emissions
[Tons; 1999 Winter Season]
----------------------------------------------------------------------------------------------------------------
NPS unit HC CO NO_X PM
----------------------------------------------------------------------------------------------------------------
Denali NP & Preserve............................................ >9.8 >26.1 >0.08 >0.24
Grand Teton NP.................................................. 13.7 36.6 0.1 0.3
Rocky Mountain NP............................................... 106.7 284.7 0.8 2.6
Voyageurs NP.................................................... 138.5 369.4 1.1 3.4
Yellowstone NP.................................................. 492.0 1,311.9 3.8 12.0
----------------------------------------------------------------------------------------------------------------
Source: Letter from Aaron J. Worstell, Environmental Engineer, National Park Service, Air Resources Division, to
Drew Kodjak, August 21, 2001, particularly Table 1. Docket No. A-2000-01, Document No. II-G-178.

Inventory analysis performed by the National Park Service for
Yellowstone National Park suggests that snowmobile emissions can be a
significant source of total annual mobile source emissions for the park
year round. Table II.D-4 shows that in the 1998 winter season
snowmobiles contributed 64 percent, 39 percent, and 30 percent of HC,
CO, and PM emissions.\108\ It should be noted that the snowmobile
emission factors used to estimate these contributions are currently
under review, and the snowmobile emissions may be revised down.
However, when the emission factors used by EPA in its NONROAD model are
used, the contribution of snowmobiles to total emissions in Yellowstone
remains significant: 59 percent, 33 percent, and 45 percent of HC, CO
and PM emissions. The University of Denver used remote-sensing
equipment to estimate snowmobile HC emissions at Yellowstone during the
winter of 1998-1999, and estimated that snowmobiles contribute 77% of
annual hydrocarbon emissions at the park.\109\ The portion of
wintertime emissions attributable to snowmobiles is even higher, since
all snowmobile emissions occur during the winter months.
---------------------------------------------------------------------------

\108\ National Park Service, February 2000. Air Quality Concerns
Related to Snowmobile Usage in National Parks. Air Docket A-2000-01,
Document No. II-A-44.
\109\ G. Bishop, et al., Snowmobile Contributions to Mobile
Source Emissions in Yellowstone National Park, Environmental Science
and Technology, Vol. 35, No. 14, at 2873. Docket No. A-2000-01,
Document No. II-A-47.

Table II.D-4.--1998 Annual HC Emissions (tpy), Yellowstone National Park
--------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------
HC
CO
NO_X
PM
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source:
Coaches............................................... 2.69 0% 24.29 1% 0.42 0% 0.01 0%
Autos................................................. 307.17 33% 2,242.12 54% 285.51 88% 12.20 60%
RVs................................................... 15.37 2% 269.61 6% 24.33 7% 0.90 4%
Snowmobiles........................................... 596.22 64% 1,636.44 39% 1.79 1% 6.07 30%
Buses................................................. 4.96 1% 18.00 0% 13.03 4% 1.07 5%
------------ ------------ ------------ ------------
Total........................................... 926.4 4,190.46 325.08 20.25
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: National Park Service, February 2000. Air Quality Concerns Related to Snowmobile Usage in National Parks.
Air Docket A-2000-01, Document No. II-A-44.

The information presented in this discussion indicates that
snowmobiles are significant emitters of pollutants that are known to
contribute to visibility impairment in some Class I areas. Annual and
particularly wintertime hydrocarbon emissions from snowmobiles are high
in the five parks considered in Table II.D-4, with two parks having HC
emissions nearly as high as Yellowstone (Rocky Mountain and Voyageurs).
The proportion of snowmobile emissions to emissions from other sources
affecting air quality in these parks is likely to be similar to that in
Yellowstone.
c. Snowmobiles and personal exposure to air toxics and CO.
Snowmobile users can be exposed to high air toxic and CO emissions,
both because they sit very close to the vehicle's exhaust port and
because it is common for them to ride their vehicles on groomed trails
where they travel fairly close behind other snowmobiles. Because of
these riding patterns, snowmobilers breathe exhaust emissions from
their own vehicle, the vehicle directly in front, as well as those
farther up the trail. This can lead to relatively high personal
exposure levels of harmful pollutants. A study of snowmobile rider CO
exposure conducted at Grand Teton National Park showed that a
snowmobiler riding at distances of 25 to 125 feet behind another
snowmobiler and traveling at speeds from 10 to 40 mph can be exposed to
average CO levels ranging from 0.5 to 23 ppm, depending on speed and
distance. The highest CO level measured in this study was 45 ppm, as
compared to the current 1-hour NAAQS for CO of 35 ppm.\110\ While
exposure levels can be less if a snowmobile drives 15 feet off the
centerline of the lead snowmobile, the exposure levels are still of
concern. This study led to the development of an empirical model for
predicting CO exposures from riding behind snowmobiles.
---------------------------------------------------------------------------

\110\ Snook and Davis, 1997, ``An Investigation of Driver
Exposure to Carbon Monoxide While Traveling Behind Another
Snowmobile.'' Docket No. A-2000-01, Document Number II-A-35.
---------------------------------------------------------------------------

Hydrocarbon speciation for snowmobile emissions was performed for
the State of Montana in a 1997 report.\111\ Using the empirical model
for CO from the Grand Teton exposure study with benzene emission rates
from the State of Montana's emission study, benzene exposures for
riders driving behind a single snowmobile were predicted to range from
1.2E+02 to 1.4E+03 µg/m3. Using the same model to predict
exposures when riding at the end of a line of six snowmobiles spaced 25
feet apart yielded exposure predictions of 3.5E+03, 1.9E+03,

[[Page 51114]]

1.3E+03, and 1.2E+03 µg/m3 benzene. at 10, 20, 30, and 40 mph,
respectively.
---------------------------------------------------------------------------

\111\ Emissions from Snowmobile Engines Using Bio-based Fuels
and Lubricants, Southwest Research Institute, August, 1997, at 22.
Docket No. A-2000-01, Document Number II-A-50.
---------------------------------------------------------------------------

The cancer risk posed to those exposed to benzene emissions from
snowmobiles must be viewed within the broader context of expected
lifetime benzene exposure. Observed monitoring data and predicted
modeled values demonstrate that a significant cancer risk already
exists from ambient concentrations of benzene for a large portion of
the US population. The Agency's 1996 National-Scale Air Toxics
Assessment of personal exposure to ambient concentrations of air toxic
compounds emitted by outside sources (e.g. cars and trucks, power
plants) found that benzene was among the five air toxics that appear to
pose the greatest risk to people nationwide. This national assessment
found that for approximately 50% of the US population in 1996, the
inhalation cancer risks associated with benzene exceeded 10 in one
million. Modeled predictions for ambient benzene from this assessment
correlated well with observed monitored concentrations of benzene
ambient concentrations.
Specifically, the draft National-Scale Assessment predicted
nationwide annual average benzene exposures from outdoor sources to be
1.4 µg/m3.\112\ In comparison, snowmobile riders and those
directly exposed to snowmobile exhaust emissions had predicted benzene
levels two to three orders of magnitude greater than the 1996 national
average benzene concentrations.\113\ These elevated levels are also
known as air toxic ``hot spots,'' which are of particular concern to
the Agency. Thus, total annual average exposures to typical ambient
benzene concentrations combined with elevated short-term exposures to
benzene from snowmobiles may pose a significant risk of adverse public
health effects to snowmobile riders and those exposed on a frequent
basis to exhaust benzene emissions from snowmobiles. We request comment
on this issue.
---------------------------------------------------------------------------

\112\ National-Scale Air Toxics Assessment for 1996, EPA-453/R-
01-003, Draft, January 2001.
\113\ Technical Memorandum, Chad Bailey, Predicted benzene
exposures and ambient concentrations on and near snowmobile trails,
August 17, 2001. Air Docket A-2000-01, Document No. II-B-27.
---------------------------------------------------------------------------

Since snowmobile riders often travel in large groups, the riders
towards the back of the group are exposed to the accumulated exhaust of
those riding ahead. These exposure levels can continue for hours at a
time. An additional consideration is that the risk to health from CO
exposure increases with altitude, especially for unacclimated
individuals. Therefore, a park visitor who lives at sea level and then
rides his or her snowmobile on trails at high-altitude is more
susceptible to the effects of CO than local residents.
In addition to snowmobilers themselves, people who are active in
proximity to the areas where snowmobilers congregate may also be
exposed to high CO levels. An OSHA industrial hygiene survey reported a
peak CO exposure of 268 ppm for a Yellowstone employee working at an
entrance kiosk where snowmobiles enter the park. This level is greater
than the NIOSH peak recommended exposure limit of 200 ppm. OSHA's
survey also measured employees' exposures to several air toxics.
Benzene exposures in Yellowstone employees ranged from 67-600
µg/m3, with the same individual experiencing highest CO and
benzene exposures. The highest benzene exposure concentrations exceeded
the NIOSH Recommended Exposure Limit of 0.1 ppm for 8-hour
exposures.\114\
---------------------------------------------------------------------------

\114\ U.S. Department of Labor, OSHA, Billings Area Office,
``Industrial Hygiene Survey of Park Employee Exposures During Winter
Use at Yellowstone National Park,'' February 19 through February 24,
2000. Docket No. A-2000-01, Document Number II-A-37; see also
Industrial Hygiene Consultation Report prepared for Yellowstone
National Park by Tim Radtke, CIH, Industrial Hygienist, June 1997.
Docket A-2000-01, Document No. A-II-41.
---------------------------------------------------------------------------

d. Summary. For all of the reasons described in this section, we
continue to believe it is appropriate to set emission standards for
snowmobiles. At the national level, these engines contribute to CO
levels in several nonattainment areas. Snowmobiles contribute
significantly to hydrocarbon emissions that are known to contribute to
visibility impairment in Class I areas. In addition, snowmobilers
riding in a trail formation, as well as park attendants and other
bystanders can experience very high levels of CO and benzene for
relatively long periods of time. The proposed standards will help
reduce these emissions and help alleviate these concerns.
2. Recreational Marine
As with snowmobiles, the usage patterns of recreational marine
engine can lead to high personal exposure levels, particularly for CO
emissions. The U.S. Coast Guard reported cases of CO poisoning caused
by recreational boat usage.\115\ These Coast Guard investigations into
recreational boating accident reports between 1989 to1998 show that 57
accidents were reported, totaling 87 injuries and 32 fatalities, that
involved CO poisoning. An article in the Journal of the American
Medical Association also discusses CO poisoning among recreational boat
users.\116\ This study reports 21 incidences of CO poisoning from
sterndrive and inboard engines; two-thirds of these incidences occurred
when the boat was cruising.
---------------------------------------------------------------------------

\115\ Summarized in an e-mail from Phil Cappel of the U.S. Coast
Guard to Mike Samulski of the U.S. Environmental Protection Agency,
October 19, 2000. Docket A-2000-01, Document No. II-A-46.
\116\ Silvers, S., Hampton, N., ``Carbon Monoxide Poisoning
Among Recreational Boaters,'' JAM, November 22/29, 1995, Vol 274,
No. 20. Docket A-2000-01, Document No. 11-A-45.
---------------------------------------------------------------------------

The CO exposure to boaters comes from three general sources. First,
CO may enter the engine compartment and cabin spaces from leaks in the
exhaust system. Second, boaters may be exposed to CO if they are near
the engine when it is idling such as swimming behind the boat. Third,
CO may be drawn into the boat when it is cruising due to a back draft
of air into the boat known as the ``station wagon effect.'' \117\
---------------------------------------------------------------------------

\117\ United States Coast Guard, ``Boating Safety Circular 64,''
December 1986. Docket A-2000-01, Document No. II-A-43.
---------------------------------------------------------------------------

3. Large SI Engines
Exhaust emissions from applications with significant indoor use can
expose individual operators or bystanders to dangerous levels of
pollution. Forklifts, ice-surfacing machines, sweepers, and carpet
cleaning equipment are examples of large industrial spark-ignition
engines that often operate indoors or in other confined spaces.
Forklifts alone account for over half of the engines in this category.
Indoor use may include extensive operation in a temperature-controlled
environment where ventilation is kept to a minimum (for example, for
storing, processing, and shipping produce).
The principal concern for human exposure relates to CO emissions.
One study showed several forklifts operating on liquefied petroleum gas
(LPG) with measured CO emissions ranging from 10,000 to 90,000 ppm (1
to 9 percent).\118\ The threshold limit value for a time-weighted
average 8-hour workplace exposure set by the American Conference of
Governmental Industrial Hygienists is 25 ppm. The recommended limit
adopted by the National Institute for Occupational Safety and Health is
35 ppm for 8-hour exposure and maximum instantaneous exposure of 200
ppm. While these lower numbers refer to ambient concentrations, the
very high documented exhaust concentrations

[[Page 51115]]

would quickly exceed the ambient levels in any operation in enclosed
areas without extraordinary ventilation.
---------------------------------------------------------------------------

\118\ ``Warehouse Workers' Headache, Carbon Monoxide Poisoning
from Propane-Fueled Forklifts,'' Thomas A. Fawcett, et al, Journal
of Occupational Medicine, January 1992, p.12. Docket A-2000-01,
Document No. II-A-36.
---------------------------------------------------------------------------

Large SI engines operating on any fuel can have very high CO
emission levels. While our emission modeling estimates a significantly
lower emission rate for engines fueled by LPG relative to gasoline, the
study described above shows clearly that individual engines that should
have low CO emissions can, through maladjustment or normal degradation,
reach dangerous emission levels.
Additional exposure concerns occur at ice rinks. Numerous papers
have identified ice-surfacing machines with spark-ignition engines as
the source of dangerous levels of CO and NO₂, both for
skaters and for spectators.\119\ This is especially problematic for
skaters, who breathe air in the area where pollutant concentration is
highest, with higher respiration rates resulting from their high level
of physical activity. This problem has received significant attention
from the medical community.
---------------------------------------------------------------------------

\119\ ``Summary of Medical Papers Related to Exhaust Emission
Exposure at Ice Rinks,'' EPA Memorandum from Alan Stout to Docket A-
2000-01. Docket A-2000-01, Document No. II-A-38.
---------------------------------------------------------------------------

In addition to CO emissions, HC emissions from all Large SI engines
can lead to increased exposure to harmful pollutants, particularly air
toxic emissions. Since many gasoline or dual-fuel engines are in
forklifts that operate indoors, reducing evaporative emissions could
have additional health benefits to operators and other personnel. Fuel
vapors can also cause odor problems.

III. Nonroad: General Concepts

This section describes general concepts concerning the proposed
emission standards and the ways in which a manufacturer would show
compliance with these standards. Clean Air Act Section 213 requires us
to set standards that achieve the greatest degree of emission reduction
achievable through the application of technology that will be
available, giving appropriate consideration to cost, noise, energy, and
safety factors. In addition to emission standards, this document
describes a variety of proposed requirements such as applying for
certification, labeling engines, and meeting warranty requirements to
define a process for implementing the proposed emission-control program
in an effective way.
The discussions in this section are general and are meant to cover
all the nonroad engines and vehicles that would be subject to the
proposed standards. Refer to the discussions of specific engine
programs, contained in Sections IV through VI, for more information
about specific requirements for different categories of nonroad engines
and vehicles. We request comment on all aspects of these general
program provisions.
This section describes general nonroad provisions related to
certification prior to sale or introduction into commerce. Section VII
describes several proposed compliance provisions that apply generally
to nonroad engines, and Section VIII similarly describes general
testing provisions.

A. Scope of Application

As noted in Section I.C.1, this proposal covers recreational marine
diesel engines, nonroad industrial SI engines rated over 19 kW, and
recreational vehicles introduced into commerce in the United States.
The following sections describe generally when emission standards apply
to these products. Refer to the specific program discussion below for
more information about the scope of application and timing of the
proposed standards.
1. Do the Standards Apply to All Engines and Vehicles or Only to New
Engines and Vehicles?
The scope of this proposal is broadly set by Clean Air Act section
213(a)(3), which instructs us to set emission standards for new nonroad
engines and new nonroad vehicles. Generally speaking, the proposed rule
is intended to cover all new engines and vehicles in the categories
listed above (including any associated equipment or vessels).\120\ Once
the emission standards apply to a group of engines or vehicles,
manufacturers must get a certificate of conformity from us before
selling them in the United States.\121\ This includes importation and
any other means of introducing engines and vehicles into commerce. We
also require equipment manufacturers that install engines from other
companies to install only certified engines once emission standards
apply. The certificate of conformity (and corresponding engine label)
provide assurance that manufacturers have met their obligation to make
engines that meet emission standards over the useful life we specify in
the regulations.
---------------------------------------------------------------------------

\120\ For some categories, we are proposing vehicle-based or
vessel-based standards. In these cases, the term ``engine'' in this
document applies equally to the vehicles or vessels.
\121\ The term ``manufacturer'' includes any individual or
company introducing engines into commerce in the United States.
---------------------------------------------------------------------------

2. How Do I Know if My Engine or Equipment Is New?
We are proposing to define ``new'' consistent with previous
rulemakings. Under the proposed definition, a nonroad engine (or
nonroad equipment) is considered new until its title has been
transferred to the ultimate purchaser or the engine has been placed
into service. This proposed definition would apply to both engines and
equipment, so the nonroad equipment using these engines, including all-
terrain vehicles, snowmobiles, off-highway motorcycles, and other land-
based nonroad equipment would be considered new until their title has
been transferred to an ultimate buyer. In Section III.B.1 we describe
how to determine the model year of individual engines and vehicles.
To further clarify the proposed definition of new nonroad engine,
we are proposing to specify that a nonroad engine, vehicle, or
equipment is placed into service when it is used for its intended
purpose. We are therefore proposing that an engine subject to the
proposed standards is used for its functional purpose when it is
installed on an all-terrain vehicle, snowmobile, off-highway
motorcycle, marine vessel, or other piece of nonroad equipment. We need
to make this clarification because some engines are made by modifying a
highway or land-based nonroad engine that has already been installed on
a vehicle or other piece of equipment. For example, someone can install
an engine in a recreational marine vessel after it has been used for
its functional purpose as a land-based highway or nonroad engine. We
believe this is a reasonable approach because the practice of adapting
used highway or land-based nonroad engines may become more common if
these engines are not subject to the standards in this proposal.
In summary, an engine would be subject to the proposed standards if
it is:

Freshly manufactured, whether domestic or imported; this may
include engines produced from engine block cores
Installed for the first time in nonroad equipment after having
powered a car or a category of nonroad equipment subject to different
emission standards
Installed in new nonroad equipment, regardless of the age of
the engine
Imported (new or used)
3. When Do Imported Engines Need To Meet Emission Standards?
The proposed emission standards would apply to all new engines that
are used in the United States. According to

[[Page 51116]]

Clean Air Act section 216, ``new'' includes engines that are imported
by any person, whether freshly manufactured or used. Thus, the proposed
program would include engines that are imported for use in the United
States, whether they are imported as loose engines or if they are
already installed on a marine vessel, recreational vehicle, or other
piece of nonroad equipment, built elsewhere. All imported engines would
need an EPA-issued certificate of conformity to clear customs, with
limited exemptions (as described below).
If an engine or marine vessel, recreational vehicle, or other piece
of nonroad equipment that was built after emission standards take
effect is imported without a currently valid certificate of conformity,
we would still consider it to be a new engine, vehicle, or vessel. This
means it would need to comply with the applicable emission standards.
Thus, for example, a marine vessel manufactured in a foreign country in
2007, then imported into the United States in 2010, would be considered
``new.'' The engines on that piece of equipment would have to comply
with the requirements for the 2007 model year, assuming no other
exemptions apply. This provision is important to prevent manufacturers
from avoiding emission standards by building vessels abroad,
transferring their title, and then importing them as used vessels.
With regard to recreational vehicles, the United States Customs
Service currently allows foreign nationals traveling with their
personal automobiles, trailers, aircraft, motorcycles, or boats to
import such vehicles without having to pay a tariff, so long as they
are used in the United States only for the transportation of such
person.\122\ We propose to use this approach in our regulation of
emissions from recreational vehicles (snowmobiles, off-highway
motorcycles, and all-terrain vehicles). We propose to allow
noncompliant recreational vehicles that are the personal property of
foreign nationals to be imported into the United States as long as the
foreign national bringing them into the country intends to use them
only for his or her recreational purposes and they are not left here
when the person leaves the country (they are either taken back or
destroyed). In other words, such recreational vehicles would not be
considered ``new'' for the purpose of determining whether they must
comply with the proposed emission limits. We propose that a time limit
of one year on this exemption so that recreational vehicles imported
for more than that period of time would be considered imported, and
therefore ``new'' and subject to the proposed emission limits. We are
also proposing that this time period cannot be extended. This time
limit is designed to prevent a person from using the exemption to
effectively circumvent the standards.
---------------------------------------------------------------------------

\122\ Harmonized Tariff Schedule of the United States (2001)
(Rev. 1), subheading 9804.00.35. A copy of this document is included
in Air Docket A-2000-01, at Document No. II-A-82.
---------------------------------------------------------------------------

This exemption generally would not apply to any commercial engines
that would be subject to emission standards. To import noncomplying
engines for commercial applications, the importer would have to meet
the requirements for a different exemption, as described in Section
VII.
4. Do the Standards Apply to Exported Engines or Vehicles?
Engines or vehicles intended for export would generally not be
subject to the requirements of the proposed emission-control program.
However, engines that are exported and subsequently re-imported into
the United States would need to be certified. For example, this would
be the case when a foreign company purchases engines manufactured in
the United States for installation on a marine vessel, recreational
vehicle, or other nonroad equipment for export back to the United
States. Those engines would be subject to the emission standards that
apply on the date the engine was originally manufactured. If the engine
is later modified and certified (or recertified), the engine is subject
to emission standards that apply on the date of the modification. So,
for example, foreign boat builders buying U.S.-made engines without
recertifying the engines will need to make sure they purchase complying
engines for the products they sell in the U.S.
5. Are There Any New Engines or Vehicles That Would Not Be Covered?
We are proposing to extend our basic nonroad exemptions to the
engines and vehicles covered by this proposal. These include the
testing exemption, the manufacturer-owned exemption, the display
exemption, and the national security exemption. These exemptions are
described in more detail in Section VII.C.
In addition, the Clean Air Act does not consider stationary engines
or engines used solely for competition to be nonroad engines, so the
proposed emission standards do not apply to them. Refer to the program
discussions below for a discussion of how these exclusions apply for
different categories of engines.

B. Emission Standards and Testing

1. How Does EPA Determine the Emission Standards?
Our general goal in designing the proposed standards is to develop
a program that will achieve significant emission reductions. We are
guided by Clean Air Act section 213(a)(3), which instructs us to
``achieve the greatest degree of emission reduction achievable through
the application of technology the Administrator determines will be
available for the engines or vehicles to which such standards apply,
giving appropriate consideration to the cost of applying such
technology within the period of time available to manufacturers and to
noise, energy, and safety factors associated with the application of
such technology.'' The Act also instructs us to first consider
standards equivalent in stringency to standards for comparable motor
vehicles or engines (if any) regulated under section 202, taking into
consideration technological feasibility, costs, and other factors.
Engines subject to the proposed exhaust emission standards would
have to meet the standards based on measured emissions of specified
pollutants such as NO_X, HC, or CO, though not all engines
will have standards for each pollutant. Diesel engines generally must
also meet a PM emission standard. In addition, there may be
requirements for crankcase or evaporative emissions, as described
below.
The proposed emission standards would be effective on a model-year
basis. We are proposing to define model year much like we do for
passenger cars. It would generally mean either the calendar year or
some other annual production period based on the manufacturer's
production practices. For example, manufacturers could start selling
2006 model year engines as early as January 2, 2005, as long as the
production period extends until at least January 1, 2006. All of a
manufacturer's engines from a given model year would have to meet
emission standards for that model year. For example, manufacturers
producing new engines in the 2006 model year would need to comply with
the 2006 standards. Refer to the individual program discussions below
or the regulations for additional information about model year periods,
including how to define what model year means in less common scenarios,
such as installing used engines in new equipment.

[[Page 51117]]

2. What Standards Would Apply to Crankcase and Evaporative Emissions?
Due to blow-by of combustion gases and the reciprocating action of
the piston, exhaust emissions can accumulate in the crankcase of four-
stroke engines. Uncontrolled engine designs route these vapors directly
to the atmosphere, where they contribute to ambient levels of these
pollutants. We have long required that automotive engines prevent
emissions from their crankcases. Manufacturers generally do this by
routing crankcase vapors through a valve into the engine's air intake
system. We are proposing to require that engines prevent crankcase
emissions. We request comment on this proposed requirement for
individual types of engines, as described in those sections below.
For industrial spark-ignition engines, we are proposing standards
to limit evaporative emissions. Evaporative emissions result from
heating gasoline (or other volatile fuels) in a tank that is vented to
the atmosphere. See Section IV for additional information.
3. What Duty Cycles Is EPA Proposing for Emission Testing?
Testing an engine for exhaust emissions typically consists of
exercising it over a prescribed duty cycle of speeds and loads,
typically using an engine or chassis dynamometer. The duty cycle used
to measure emissions for certification, which simulates operation in
the field, is critical in evaluating the likely emissions performance
of engines designed to emission standards.
Steady-state testing consists of engine operation for an extended
period at several speed-load combinations. Associated with these test
points are weighting factors that allow calculation of a single
weighted-average steady-state emission level in g/kW. Transient testing
involves a continuous trace of specified engine or vehicle operation;
emissions are collected over the whole testing period for a single mass
measurement.
See Section VIII.C for a discussion of how we define maximum test
speed and intermediate speed for engine testing. Refer to the program
discussions below for more information about the type of duty cycle
required for testing the various engines and vehicles.
4. How Do Adjustable Engine Parameters Affect Emission Testing?
Many engines are designed with components that can be adjusted for
optimum performance under changing conditions, such as varying fuel
quality, high altitude, or engine wear. Examples of adjustable
parameters include spark timing, idle speed setting, and fuel injection
timing. While we recognize the need for this practice, we are also
concerned that engines maintain a consistent level of emission control
for the whole range of adjustability. We are therefore proposing to
require manufacturers to show that their engines meet emission
standards over the full adjustment range.
Manufacturers would also have to provide a physical stop to prevent
adjustment outside the established range. Operators would then be
prohibited by the anti-tampering provisions from adjusting engines
outside this range. Refer to the proposed regulatory text for more
information about adjustable engine parameters. See especially the
proposed sections 40 CFR 1048.115 for industrial SI engines and 40 CFR
1051.115 for recreational vehicles.
5. What Are Voluntary Low-Emission Engines and Blue Sky Standards?
Several state and environmental groups and manufacturers of
emission controls have supported our efforts to develop incentive
programs to encourage the use of engine technologies that go beyond
federal emission standards. Some companies have already significantly
developed these technologies. In the final rule for land-based nonroad
diesel engines, we included a program of voluntary standards for low-
emitting engines, referring to these as ``Blue Sky Series'' engines (63
FR 56967, October 23, 1998). We included similar programs in several of
our other nonroad rules, including commercial marine diesel. The
general purposes of such programs are to provide incentives to
manfuacturers to produce clean products as well as create market
choices and opportunities for environmental information for consumers
regarding such products. The voluntary aspects of these programs, which
in part provides an incentive for manufacturers willing to certify
their products to more stringent standards than necessary, is an
important part of the overall application of ``Blue Sky Series''
programs.
We are proposing voluntary Blue Sky Series standards for many of
the engines subject to this proposal. Creating a program of voluntary
standards for low-emitting engines, including testing and durability
provisions to help ensure adequate in-use performance, will be a step
forward in advancing emission-control technologies. While these are
voluntary standards, they become binding once a manufacturer chooses to
participate. EPA certification will therefore provide protection
against false claims of environmentally beneficial products. For the
program to be most effective, however, incentives should be in place to
motivate the production and sale of these engines. We solicit ideas
that could encourage the creation of these incentive programs by users
and state and local governments. We also request comment on additional
measures we could take to encourage development and introduction of
these engines. Finally, we request comment on the Blue Sky Series
approach in general as it would apply to the engines covered by this
proposed rule.

C. Demonstrating Compliance

We are proposing a compliance program to accompany emission
standards. This consists first of a process for certifying engine
models. In addition to certification testing, we are proposing several
provisions to ensure that emission-control systems continue to function
over long-term operation in the field. Most of these certification and
durability provisions are consistent with previous rulemakings for
other nonroad engines. Refer to the discussion of the specific programs
below for additional information about these requirements for each
engine category.
1. How Would I Certify My Engines?
We are proposing a certification process similar to that already
adopted for other engines. Manufacturers generally test representative
prototype engines and submit the emission data along with other
information to EPA in an application for a Certificate of Conformity.
If we approve the application, then the manufacturer's Certificate of
Conformity allows the manufacturer to produce and sell the engines
described in the application in the U.S.
We are proposing that manufacturers certify their engine models by
grouping them into engine families. Under this approach, engines
expected to have similar emission characteristics would be classified
in the same engine family. The engine family definition is fundamental
to the certification process and to a large degree determines the
amount of testing required for certification. The proposed regulations
include specific engine characteristics for grouping engine families
for each category of engines. To address a manufacturer's unique
product mix, we may approve using broader or narrower engine families.

[[Page 51118]]

Engine manufacturers are generally responsible to build engines
that meet the emission standards over each engine's useful life. The
useful life we adopt by regulation is intended to reflect the period
during which engines are designed to properly function without being
remanufactured. Useful life values, which are expressed in terms of
years or amount of operation (in hours or kilometers), vary by engine
category, as described in the following sections. Consistent with other
recent EPA programs, we would generally consider this useful life value
in amount of operation to be a minimum value and would require
manufacturers to comply for a longer period in those cases where they
design their engines to operate longer than the minimum useful life. As
proposed, manufacturers would be required to estimate the rate of
deterioration for each engine family over its useful life.
Manufacturers would show that each engine family meets the emission
standards after incorporating the estimated deterioration in emission
control.
The emission-data engine is the engine from an engine family that
will be used for certification testing. To ensure that all engines in
the family meet the standards, we are proposing that manufacturers
select the engine most likely to exceed emission standards in a family
for certification testing. In selecting this ``worst-case'' engine, the
manufacturer uses good engineering judgment. Manufacturers would
consider, for example, all engine configurations and power ratings
within the engine family and the range of installed options allowed).
Requiring the worst-case engine to be tested ensures that all engines
within the engine family are complying with emission standards.
We are proposing to require manufacturers to include in their
application for certification the results of all emission tests from
their emission-data engines, including any diagnostic-type measurements
(such as ppm testing) and invalidated tests. This complete set of test
data ensures that the valid tests that form the basis of the
manufacturer's application are a robust indicator of emission-control
performance, rather than a spurious or incidental test result. We
request comment on these data-reporting requirements.
Clean Air Act section 206(h) specifies that test procedures for
certifying engines (including the test fuel) should adequately
represent in-use operation. We are proposing test fuel specifications
intended to represent in-use fuels. Engines would have to meet the
standards on fuels with properties anywhere in the range of proposed
test fuel specifications. The test fuel is generally to be used for all
testing associated with the regulations proposed in this document,
including certification, production-line testing, and in-use testing.
Refer to the program discussions below for a discussion of the test
fuel proposed for different categories of engines.
We are proposing to require engine manufacturers to give engine
buyers instructions for properly maintaining their engines. We are
including limitations on the frequency of scheduled maintenance that a
manufacturer may specify for emission-related components to help ensure
that emission-control systems don't depend on an unreasonable
expectation of maintenance in the field. These maintenance limits would
also apply during any service accumulation that a manufacturer may do
to establish deterioration factors. This approach is common to all our
engine programs. It is important to note, however, that these
provisions would not limit the maintenance an operator could perform.
It would merely limit the maintenance that operators would be expected
to perform on a regularly scheduled basis. Refer to the discussion of
the specific programs below for additional information about the
allowable maintenance intervals for each category of engines.
Once an engine family is certified, we would require every engine a
manufacturer produces from the engine family to have an engine label
with basic identifying information. We request comment on the proposed
requirements for the design and content of engine labels, which are
detailed in Sec. 1048.135 and Sec. 1051.135 of the proposed regulation
text.
2. What Warranty Requirements Apply to Certified Engines?
Consistent with our current emission-control programs, we are
proposing that manufacturers provide a design and defect warranty
covering emission-related components. As required by the Clean Air Act,
the proposed regulations would require that the warranty period must be
longer than the minimum period we specify if the manufacturer offers a
longer mechanical warranty for the engine or any of its components;
this includes extended warranties that are available for an extra
price. See the proposed regulation language for a description of which
components are emission-related.
If an operator makes a valid warranty claim for an emission-related
component during the warranty period, the engine manufacturer is
generally obligated to replace the component at no charge to the
operator. The engine manufacturer may deny warranty claims if the
operator failed to do prescribed maintenance that contributed to the
warranty claim.
We are also proposing a defect reporting requirement that applies
separate from the emission-related warranty (see Section VII.F). In
general, defect reporting applies when a manufacturer discovers a
pattern of component failures, whether that information comes from
warranty claims, voluntary investigation of product quality, or other
sources.
3. Can I Meet Standards With Emission Credits?
Many of our emission-control programs have a voluntary emission-
credit program to facilitate implementation of emission controls. An
emission-credit program is an important factor we take into
consideration in setting emission standards that are appropriate under
Clean Air Act section 213. An emission-credit program can reduce the
cost and improve the technological feasibility of achieving standards,
helping to ensure the attainment of the standards earlier than would
otherwise be possible. Manufacturers gain flexibility in product
planning and the opportunity for a more cost-effective introduction of
product lines meeting a new standard. Emission-credit programs also
create an incentive for the early introduction of new technology, which
allows certain engine families to act as trailblazers for new
technology. This can help provide valuable information to manufacturers
on the technology before they apply the technology throughout their
product line. This early introduction of clean technology improves the
feasibility of achieving the standards and can provide valuable
information for use in other regulatory programs that may benefit from
similar technologies.
Emission-credit programs may involve averaging, banking, or
trading. Averaging would allow a manufacturer to certify one or more
engine families at emission levels above the applicable emission
standards, as long as the increased emissions are offset by one or more
engine families certified below the applicable standards. The over-
complying engines generate credits that are used by the under-complying
engines. Compliance is determined on a total mass emissions basis to
account for differences in production volume, power and useful life
among engine families. The average of all emissions

[[Page 51119]]

for a particular manufacturer's production must be at or below that
level of the applicable emission standards. This calculation generally
factors in sales-weighted average power, production volume, useful
life, and load factor. Banking and trading would allow a manufacturer
to generate emission credits and bank them for future use in its own
averaging program in later years or sell them to another company.
In general, a manufacturer choosing to participate in an emission-
credit program would certify each participating engine family to a
Family Emission Limit. In its certification application, a manufacturer
would determine a separate Family Emission Limit for each pollutant
included in the emission-credit program. The Family Emission Limit
selected by the manufacturer becomes the emission standard for that
engine family. Emission credits are based on the difference between the
emission standard that applies and the Family Emission Limit. We would
expect the manufacturer to meet the Family Emission Limit for all
emission testing. At the end of the model year, manufacturers would
generally need to show that the net effect of all their engine families
participating in the emission-credit program is a zero balance or a net
positive balance of credits. A manufacturer could generally choose to
include only a single pollutant from an engine family in the emission-
credit program or, alternatively, to establish a Family Emission Limit
for each of the regulated pollutants.
An alternative approach to requiring manufacturers to choose Family
Emission Limits would be for us to create a discrete number of emission
levels or ``bins'' above and below the proposed standard that
manufacturers could certify to. These bin levels would then replace the
Family Emission Levels in the credit calculations. We request comment
on whether we should consider this approach for the engines covered by
this proposal. The advantage of bins are that they can be defined by
step changes in technology, which gives more assurance of emission
reduction than Family Emission Limits which can change slightly with
only marginal changes to the engine.
Refer to the program discussions below for more information about
emission-credit provisions for individual engine categories. We request
comment on all aspects of the emission-credit programs discussed in
this proposal. In particular, we request comment on the structure of
the proposed emission-credit programs and how the various provisions
may affect manufacturers' ability to utilize averaging, banking, or
trading to achieve the desired emission-reductions in the most
efficient and economical way.
4. What Are the Proposed Production-Line Testing Requirements?
We are proposing production-line testing for recreational marine
diesel engines, recreational vehicles, and Large SI engines. According
to these requirements, manufacturers would routinely test production-
line engines to help ensure that newly assembled engines control
emissions at least as well as the emission-data engines tested for
certification. Production-line testing serves as a quality-control
step, providing information to allow early detection of any problems
with the design or assembly of freshly manufactured engines. This is
different than selective enforcement auditing, in which we would give a
test order for more rigorous testing for production-line engines in a
particular engine family (see Section VII.E). Production-line testing
requirements are already common to several categories of engines as
part of their emission-control program.
A manufacturer's liability under the production-line testing
program is limited to the test engine and any future production. If an
engine fails to meet an emission standard, the manufacturer must modify
it to bring that specific engine into compliance. If too many engines
exceed emission standards, the engine family is determined to be in
noncompliance and the manufacturer will need to correct the problem for
future production. This correction may involve changes to assembly
procedures or engine design, but the manufacturer must, in any case, do
sufficient testing to show that the engine family complies with
emission standards.
The proposed production-line testing programs would depend on the
Cumulative Sum (CumSum) statistical process for determining the number
of engines a manufacturer needs to test (see the proposed regulations
for the specific calculation methodology). Each manufacturer selects
engines randomly at the beginning of a new sampling period. If engines
must be tested at a facility where final assembly is not yet completed,
manufacturers must randomly select engine components and assemble the
test engine according to their established assembly instructions. A
sampling period may be a quarter or a calendar year, depending
generally on the size of the engine family. The Cumulative Sum program
uses the emission results to calculate the number of tests required for
the remainder of the sampling period to reach a pass or fail
determination. If tested engines have relatively high emissions, the
statistical sampling method calls for an increased number of tests to
show that the engine family meets emission standards. The remaining
number of tests is recalculated after the manufacturer tests each
engine. Engines selected should cover the broadest range of production
configurations possible. Tests should also be distributed evenly
throughout the sampling period to the extent possible.
Under the Cumulative Sum approach, individual engines can exceed
the emission standards without bringing the whole engine family into
noncompliance. Note, however, that we propose to require manufacturers
to adjust or repair every failing engine and retest it to show that it
meets the emission standards. Note also that all production-line
emission measurements must be included in the periodic reports to us.
This includes any type of screening or surveillance tests (including
ppm measurements), all data points for evaluating whether an engine
controls emissions ``off-cycle,'' and any engine tests that exceed the
minimum required level of testing.
We are proposing to further reduce the testing requirements for
engine families that consistently meet emission standards. For engine
families with no production-line tests exceeding emission standards for
two consecutive years, the manufacturer may request a reduced testing
rate. The minimum testing rate is one test per engine family for one
year. Our approval for a reduced testing rate would apply only for a
single model year.
As we have concluded in other engine programs, some manufacturers
may have unique circumstances that call for different methods to show
that production engines comply with emission standards. We therefore
propose to allow a manufacturer to suggest an alternate plan for
testing production-line engines, as long as the alternate program is as
effective at ensuring that the engines will comply. A manufacturer's
petition to use an alternate plan should address the need for the
alternative and should justify any changes from the regular testing
program. The petition must also describe in detail the equivalent
thresholds and failure rates for the alternate plan. If we approved the
plan, we would use these criteria to determine when an engine family
would become noncompliant. It is important to note that this allowance
is intended only as a flexibility, and is not intended

[[Page 51120]]

to affect the stringency of the standards or the production-line
testing program.
Refer to the specific program discussions below for additional
information about production-line testing for different types of
engines.

D. Other Concepts

1. What Are the Proposed Emission-Related Installation Instructions?
For manufacturers selling loose engines to equipment manufacturers,
we are proposing to require the engine manufacturer to develop a set of
emission-related installation instructions. This would include anything
that the installer would need to know to ensure that the engine
operates within its certified design configuration. For example, the
installation instructions could specify a total capacity needed from
the engine cooling system, placement of catalysts after final assembly,
or specification of parts needed to control evaporative emissions. We
would approve the installation instructions as part of the
certification process. If equipment manufacturers fail to follow the
established emission-related installation instructions, we would
consider this tampering, which could subject them to significant civil
penalties. Refer to the program discussions below for more information
about specific provisions related to installation instructions.
2. What Is Consumer-Choice Labeling?
California ARB has recently proposed consumer/environmental label
requirements for outboard and personal-watercraft engines. Under this
concept, manufacturers would label their engines or vehicles based on
their certified emission level. California has proposed three different
labels to differentiate varying degrees of emission control--one for
meeting the EPA 2006 standard, one for being 20 percent lower, and one
for being 65 percent below. More detail on this concept is provided in
the docket.\123\
---------------------------------------------------------------------------

\123\ ``Public Hearing to Consider Amendments to the Spark-
Ignition Marine Engine Regulations,'' Mail Out #MSC 99-15, June 22,
1999 (Docket A-2000-01, Document II-A-27).
---------------------------------------------------------------------------

We are considering a similar approach to labeling the engines
subject to this proposal. This would apply especially to consumer
products. Consumer-choice labeling would give people the opportunity to
consider varying emission levels as a factor in choosing specific
models. This may also give the manufacturer an incentive to produce
more of their cleaner engine models. A difficulty in designing a
labeling program is in creating a scheme that communicates information
clearly and simply to consumers. Given the very different emission
levels expected from the various engines, it would be difficult to
create a consistent set of labels for different engines. Also, we are
concerned that other organizations could use the labeling provisions to
mandate certain levels of emission control, rather than relying on
consumer choice as a market-based incentive. We request comment on this
approach for recreational marine engines and vessels and for
recreational vehicles.
An alternative to the promotional-type label adopted by California
ARB would be an approach that simply identifies an engine's certified
emission levels on the emission-control label. This ``informational
label'' could be used with or without defining voluntary emission
standards. This would not provide a standardized way for manufacturers
to promote their cleanest products, but it would give interested
consumers the ability to make informed choices based on a vehicle's
certified emission levels. We are proposing this approach of requiring
an engine's certified emission levels to be on the emission-control
label for engines and vehicles certified to voluntary low emission or
Blue Sky standards. We request comment on this approach and whether we
should extend this requirement to all vehicles and engines, not just
those complying with voluntary low emission standards. Also, we request
comment on the relative advantages of the different approaches to
consumer-choice labeling just discussed.
3. Are There Special Provisions for Small Manufacturers of These
Engines and Vehicles?
The Regulatory Flexibility Act, 5 U.S.C. 601-612, was amended by
the Small Business Regulatory Enforcement Act of 1996 (SBREFA), Public
Law 104-121, to ensure that concerns regarding small entities are
adequately considered during the development of new regulations that
affect them. The scope of this proposal includes many engine and
vehicle manufacturers that have not been subject to our regulations or
certification process. Many of these manufacturers are small businesses
for which a typical regulatory program may be very burdensome. The
sections describing the proposed emission-control program include
discussion of proposed special compliance provisions designed to
address this for the different engine categories. Section XI.B gives an
overview of the inter-agency process in which we developed these small-
volume provisions.

IV. Large SI Engines

A. Overview

This section applies to most nonroad spark-ignition engines rated
over 19 kW (``Large SI engines''). The companies producing Large SI
engines are typically subsidiaries of automotive companies. In most
cases, these companies modify car and truck engines for industrial
applications. However, the Large SI industry has historically taken a
much less centralized approach to designing and producing engines.
Engine manufacturers often sell dressed engine blocks without manifolds
or fuel systems. Fuel system suppliers have played a big role in
designing and calibrating nonroad engines, sometimes participating
directly in engine assembly. Several equipment manufacturers, mostly
forklift producers, also play the role of an engine manufacturer by
calibrating engine models and completing engine assembly.
The proposed emission standards would achieve emission reductions
of about 90 percent for CO, 85 percent for NO_X, and 70
percent for HC. Since the emission standards are based on engine
testing with broadly representative duty cycles, these estimated
reductions apply to all types of equipment using these engines.
Reducing Large SI engine emissions will be especially valuable to
individuals operating these engines in enclosed areas.
The cost of applying the anticipated emission-control technology to
these engines is offset by much greater cost savings from reduced fuel
consumption over the engines' operating lifetime. The large estimated
fuel and maintenance savings relative to the estimated incremental cost
of producing low-emitting engines raise the question of why normal
market forces have failed to induce manufacturers to design and sell
engines with emission-control technologies on the basis of the expected
performance improvements. As described in Chapter 5 of the Draft
Regulatory Support Document, we believe this is largely accounted for
by the difficulty of equipment purchasers to justify increased capital
spending on industrial machines, even with the potential for net
savings over the lifetime of the equipment. This in turn prevents
manufacturers from developing or implementing technologies in light of
the uncertain demand. We request comment on the market dynamics that
would prevent the development of and demand for cost-saving
technologies.
This section describes the proposed requirements that would apply
to engine manufacturers. See Section III for

[[Page 51121]]

a description of our general approach to regulating nonroad engines and
how manufacturers show that they meet emission standards. See Section
VII for additional proposed requirements for engine manufacturers,
equipment manufacturers, and others.

B. Large SI Engines Covered by This Proposal

Large SI engines covered in this section power nonroad equipment
such as forklifts, sweepers, pumps, and generators. This would include
marine auxiliary engines, but does not include marine propulsion
engines or engines used in recreational vehicles (snowmobiles, off-
highway motorcycles, and all-terrain vehicles). These other nonroad
applications are addressed elsewhere in this document.
Even though some aircraft use engines similar to the Large SI
engines described in this proposal, we are not proposing emission
standards for aircraft. Aircraft are covered under a separate part of
the Clean Air Act. EPA's current aircraft regulations define aircraft
as needing airworthiness certification from the Federal Aviation
Administration. However, neither ultra-light airplanes nor blimps are
governed by emission standards under our aircraft regulations. Ultra-
light airplanes are exempt from the airworthiness-certification
requirements in 14 CFR part 91. In contrast, blimps are subject to
airworthiness certification, but EPA's emission standards for aircraft
do not apply to them. Blimps are very likely to be able to use
conventional land-based engines for propulsion and navigation. Our
proposed definition of aircraft in these regulations would exclude all
aircraft from emission standards, including aircraft that do not
receive an airworthiness certificate from FAA. We may address this
issue in a separate Federal Register notice.
This proposal applies only to spark-ignition engines. Our most
recent rulemaking for nonroad diesel engines finalized a definition of
``compression-ignition'' that was intended to address the status of
alternative-fuel engines (63 FR 56968, October 23, 1998). We are
proposing to adopt updated definitions consistent with those already
established in previous rulemakings to clarify that all reciprocating
internal combustion engines are either spark-ignition or compression-
ignition. We request comment on whether we should revise the
definitions that differentiate between these types of engines.
Several types of engines are excluded or exempted from the proposed
requirements. The following sections describe the types of special
provisions that apply uniquely to nonrecreational spark-ignition
engines rated over 19 kW. Section VII.C covers several additional
exemptions that apply generally across programs.
1. Stationary Engine Exclusion
Consistent with the Clean Air Act, we do not treat stationary
engines as nonroad engines, so the proposed emission standards would
not apply to engines used in stationary applications. In general, an
engine is considered stationary if it will be either installed in a
fixed position or if it will be a portable (or transportable) engine
operating in a single location for at least one year. We are proposing
a requirement that these stationary engines have an engine label
identifying their excluded status. This would be especially valuable
for importing excluded engines without complication from U.S. Customs
officials. It would also help us ensure that such engines are
legitimately excluded from the emission standards proposed in this
document.
2. Exclusion for Engines Used Solely for Competition
The Clean Air Act also does not consider engines used solely for
competition to be nonroad engines. We would normally include this
exclusion directly in the regulations. For Large SI engines, however,
it seems unlikely that there would be any need for an explicit
treatment of competition engines in the regulations. Any applications
involving competition with spark-ignition engines would likely fall
under the proposed program for recreational vehicles, which has an
extensive treatment of competition engines. We request comment on the
need for more detailed consideration of Large SI engines that may be
used solely for competition.
3. Motor Vehicle Engine Exemption
In some cases an engine manufacturer may want to modify a certified
automotive engine for nonroad use to sell the engine without
recertifying it as a Large SI engine. We propose to allow for this, as
long as the manufacturer makes no changes to the engine that could
affect its exhaust or evaporative emissions. We propose to require
annual reporting for companies that use this exemption, including a
list of engine models from each company. Manufacturers must generally
meet all the requirements from 40 CFR part 86 that would apply if the
engine were used in a motor vehicle. Section 1048.605 of the proposed
regulations describes the qualifying criteria and responsibilities in
greater detail.
In addition, a vehicle manufacturer may want to produce vehicles
certified to highway emission standards for nonroad use. We propose to
allow this, as long as there is no change in the vehicle's exhaust or
evaporative emission-control systems.
4. Lawn and Garden Engine Exemption
Most Large SI engines have a total displacement greater than one
liter. The design and application of the few Large SI engines currently
being produced with displacement less than one liter are very similar
to those of engines rated below 19 kW, which are typically used for
lawn and garden applications. As described in the most recent
rulemaking for these smaller engines, we propose that manufacturers may
certify engines between 19 and 30 kW with total displacement of one
liter or less to the requirements we have already adopted in 40 CFR
part 90 for engines below 19 kW (see 65 FR 24268, April 25, 2000).
These engines would then be exempt from the requirements proposed in
this document. This approach would allow manufacturers of small air-
cooled engines to certify their engines rated between 19 and 30 kW with
the program adopted for the comparable engines with slightly lower
power ratings. This would also be consistent with the provisions
adopted by California ARB.
We are proposing the 30-kW cap to address our concern that treating
all engines under one liter as Small SI engines may be inadequate. For
example, lawn and garden engines generally don't use turbochargers or
other technologies to achieve very high power levels. However, it may
be possible for someone to design an engine under one liter with
unusually high power, which would more appropriately be grouped with
other Large SI engines with similar power capability rather than with
Small SI engines. Motorcycles, for example, may produce 120 kW from a
750 cc (0.75 liter) engine. The 30-kW maximum power rating to qualify
for treatment as Small SI engines represents a reasonable maximum power
output that is possible from SI engines under one liter with
technologies typical of lawn and garden engines. We request comment on
the suggested power threshold and on any other approaches to addressing
the issue of which standards should apply to engines in this
intermediate size and power range.
We are proposing a temporary expansion of the lawn and garden
exemption for small-volume manufacturers, as described in Section IV.E.

[[Page 51122]]

Technological, economic and environmental issues associated with
the few engine models with rated power over 19 kW, but with
displacement at or below 1 liter were previously analyzed in the
rulemaking for Small Nonroad SI engines. This proposal therefore does
not specifically address the provisions applying to them or repeat the
estimated impacts of adopting emission standards.
Conversely, we are aware that some engines rated below 19 kW may be
part of a larger family of engine models that includes engines rated
above 19 kW. This may include, for example, three- and four-cylinder
engine models that are otherwise identical. To avoid the need to
separate these engines into separate engine families (certified under
completely different control programs), we propose to allow any engine
rated under 19 kW to certify to the more stringent Large SI emission
standards. Such an engine would then be exempt from the requirements of
40 CFR part 90. Since manufacturers exercising this option would be
voluntarily meeting a more stringent emission standard, this does not
affect our earlier conclusions about the appropriate standards for
engines rated under 19 kW.
We may also consider applying the Large SI emission standards to
these smaller engines on a mandatory basis when engines above and below
19 kW share fundamental design features. We request comment on the need
for, and appropriateness of, such an approach.
5. Special Provisions for Non-Integrated Engine Manufacturers
We are aware that several Large SI engine manufacturers rely on
other companies to supply engine blocks or partially assembled engines
that are then modified for the final application. A similar situation
occurs for some marine diesel engine manufacturers. To address this for
the marine engines, we defined these companies as post-manufacture
marinizers and created a variety of provisions to address their
particular concerns (64 FR 73300; December 29, 1999).
The most important concern for these companies is the possibility
that the company supplying the base engines may discontinue production
with minimal notice. Once emission standards are in place, this would
leave the manufacturer with a need to quickly design and certify a
different engine to meet emission standards. One company has reported
that two or three months are required to apply closed-loop catalyst
systems to a new engine. With some additional time to complete the
certification, a manufacturer in this situation would face a possible
shutdown in engine assembly until the new engine is ready for
production. For marine engines, we allow post-manufacture marinizers in
this situation to request permission to produce uncertified engines for
up to one year. The post-manufacture marinizer must show that it is not
at fault and that it would face serious economic hardship without the
exemption. We request comment on the need for such a provision for
Large SI engines and on how to limit such a provision to companies that
rely on partially assembled engines from unrelated companies. If we
adopt provisions to address this concern, they would likely be similar
to those adopted for marine diesel engines (see 40 CFR 94.209(b)). We
also request comment on the potential for the proposed hardship
provisions to address this concern (see Section VII.C and the proposed
regulatory language in 40 CFR part 1068, subpart C).

C. Proposed Standards

In October 1998, California ARB adopted emission standards for
Large SI engines. We are proposing to extend requirements for these
engines to the rest of the U.S. in the near term. We are also proposing
to revise the emission standards and add various provisions in the long
term, as described below. The near-term and the long-term emission
standards are based on the use of three-way catalytic converters with
electronic fueling systems to control emissions, and would differ
primarily in terms of how well the controls are optimized. In addition
to the anticipated emission reductions, we project that these
technologies would provide large savings to operators as a result of
reduced fuel consumption and other performance improvements.
An important element of the proposed control program is the
attempted harmonization with the requirements adopted by California
ARB. We are aware that inconsistent or conflicting requirements could
lead to additional costs. Cooperation between agencies has allowed a
great degree of harmonization, as reflected in this proposed rule. In
addition to the common structure of the programs, the specific
provisions that make up the certification requirements and compliance
programs are consistent with very few exceptions. In most of the cases
where individual provisions differ, the EPA language is more general
than that adopted by California, rather than being incompatible. The
following sections describe the proposed requirements in greater
detail.
1. What Are the Proposed Standards and Compliance Dates?
We propose to adopt standards starting in the 2004 model year
consistent with those adopted by California ARB. These standards, which
apply to testing only with the applicable steady-state duty cycles, are
4 g/kW-hr (3 g/hp-hr) for HC+NO_X emissions and 50 g/kW-hr
(37 g/hp-hr) for CO emissions. See Section IV.D for further discussion
of the steady-state duty cycles. We expect manufacturers to meet these
standards using three-way catalytic converters and electronically
controlled fuel systems. These systems would be similar to those used
for many years in highway applications, but not necessarily with the
same degree of sophistication.
Proposing emission standards for these engines starting in 2004
allows less than the usual lead time for meeting EPA requirements. We
believe, however, that manufacturers will be able to achieve this by
expanding their production of the same engines they will be selling in
California at that time. We have designed our 2004 standards to require
no additional development, design, or testing beyond what California
ARB already requires. We request comment on manufacturers' ability to
produce EPA-compliant engines nationwide in 2004. Any comments should
address whether there are issues related to production capacity as
opposed to additional design or testing needs. As proposed, the
emission standards would allow us to set near-term requirements to
introduce the low-emission technologies for substantial emission
reductions with minimal lead time. We request comment on adopting these
standards for 2004 model year engines.
Testing has shown that additional time to optimize designs to
better control emissions will allow manufacturers to meet significantly
more stringent emission standards that are based on more robust
measurement procedures. Starting with the 2007 model year, we propose
to apply emission standards of 3.4 g/kW-hr (2.5 g/hp-hr) for
HC+NO_X emissions and 3.4 g/kW-hr (2.5 g/hp-hr) for CO
emissions. These standards would apply to emission measurements during
duty-cycle testing under both steady-state and transient
operation.\124\ As described in Chapter 4 of the Draft Regulatory
Support Document, we believe manufacturers can achieve these proposed
emission standards by optimizing currently available three-

[[Page 51123]]

way catalysts and electronically controlled fuel systems. As described
in Section IV.D.5, we propose to apply field-testing standards of 4.7
g/kW-hr (3.5 g/hp-hr) for HC+NO_X emissions and 5.0 g/kW-hr
(3.8 g/hp-hr) for CO emissions for 2007 and later model year engines.
---------------------------------------------------------------------------

\124\ See Section IV.D for a discussion of duty cycles.
---------------------------------------------------------------------------

The proposed 2007 standards described above reflect the importance
of adopting standards that protect human health when regulating engines
that often operate in enclosed areas, but also include numerous
applications that operate predominantly outdoors. Emission-control
technologies for Large SI engines generally pose a tradeoff between
controlling NO_X and CO emissions. Chapter 4 of the
Regulatory Support Document presents multiple scenarios of emission
standards with a comparison of calculated ambient NO, NO₂,
and CO levels. We request comment on a combination of emission
standards that would shift to increase or decrease the emphasis on
controlling CO emissions. To increase the relative control of CO
emissions, we would consider emission standards of 4.0 g/kW-hr (3.0 g/
hp-hr) HC+NO_X and 2.5 g/kW-hr (1.9 g/hp-hr). To focus more
on reducing HC+NO_X emissions, we would consider emission
standards of 2.6 g/kW-hr (2.0 g/hp-hr) HC+NO_X and 4.4 g/kW-
hr (3.3 g/hp-hr) CO. We have narrowed this range of alternative
standards to a relatively narrow range to account for the concern for
individuals who may be exposed to exhaust emissions in enclosed spaces
or other areas with limited airflow. We request comment on the
appropriate emission standards for Large SI engines and our analysis of
CO vs. HC+NO_X tradeoffs found in the RIA. We also request
comment on the potential for manufacturers to take further steps to
adopt automotive-type technologies that would reduce emissions beyond
than the levels proposed in this document, either starting in 2007 or
in a subsequent phase of standards.
Gasoline-fueled engines, which must generally operate with rich
air-fuel ratios at heavy loads to avoid premature engine wear from
overheating components, are further constrained in their ability to
simultaneously control CO and HC+NO_X emissions. Furthermore,
these engines are more likely to be used outdoors, where there is less
concern for elevated exposure levels. We are therefore proposing to
adopt alternate 2007 standards of 1.3 g/kW-hr (1.0 g/hp-hr) for
HC+NO_X emissions and 27 g/kW-hr (20 g/hp-hr) for CO
emissions. These alternate standards are based on preliminary emission
measurements with optimized gasoline-fueled engines showing the
tradeoff of increasing CO emissions at very low NC+NO_X
levels. We are not proposing any restriction on manufacturers' use of
the alternate standards (for example, for specific fuels or
applications). Rather, we expect the marketplace to ensure that low-CO
engines are selected for applications involving significant operation
in enclosed or partially enclosed areas. We believe this approach will
maximize HC+NO emission reductions from engines where that is the most
important emission contribution.
Except for these alternate standards, the proposed emission
standards would apply uniformly to all Large SI engines. As described
in the Draft Regulatory Support Document, based on our current
information, we do not believe variations among engines significantly
affect their potential to reduce emissions or their cost of meeting
emission standards. We request comment on whether it is appropriate to
differentiate between subclasses of engines to more closely tailor
emission standards to the capabilities of individual engines or based
on other relevant criteria, including cost. Also, Large SI engines
power a wide range of equipment. We request comment on the ability of
Large SI engines in various applications to incorporate emission-
control technologies and maintain control of emissions over the full
useful life. We currently have no information indicating that
application-specific emission standards are appropriate for this class
of engines, but we request comment on whether there are relevant
distinctions with respect to different applications. We further request
comment on whether application-specific standards may be relevant for
Large SI engines and, if so, what those standards should be. Commenters
should suggest an appropriate way of addressing any such distinctions
in the regulations. Finally, we have developed this proposal based on
the view that it is appropriate to set standards without regard to fuel
type to prevent incentives for manufacturers to design engines to be
fueled by fuels subject to less stringent standards. We have proposed
standards based on this approach, but request comment on whether there
are advantages to setting separate emission standards for engines
powered by different fuels, and in particular, on the appropriate
levels for such standards. A further discussion of the feasibility,
estimated cost, and emission reductions are in the Draft Regulatory
Support Document.
We believe that three years between phases of emission standards
allows manufacturers enough lead time to meet the more stringent
emission standards. The projected emission-control technologies for the
proposed 2004 emission standards should be capable of meeting the
proposed 2007 emission levels with additional optimization and testing.
In fact, manufacturers may be able to apply their optimization efforts
before 2004, leaving only the additional testing demonstration for
complying with the proposed 2007 standards. The biggest part of the
optimization effort may be related to gaining assurance that engines
will meet field-testing emission standards described in Section IV.D.5,
since engines will not be following a prescribed duty cycle. EPA
requests comment on the timing of the second phase of emission
standards. Commenters should address the need to design and certify
engines, distinguishing between time needed for developing new
technology, recalibration of existing technology, development of test
facilities, and the time needed to conduct testing. We also request
comment on the air quality implications of adjusting the date of the
long-term standards.
For gasoline and LPG engines, we are proposing the emission
standard based on total hydrocarbon measurements, while California ARB
standards are based on nonmethane hydrocarbons. We believe that
switching to measurement based on total hydrocarbons should simplify
testing, especially for field testing of in-use engines with portable
devices (See Section IV.D.5). To maintain consistency with California
ARB standards in the near term, we propose to allow manufacturers to
base their certification through 2006 on either nonmethane or total
hydrocarbons (see 40 CFR 1048.145 of the proposed regulations). Methane
emissions from controlled engines operating on gasoline or LPG are
about 0.1 g/kW&-hr. We request comment on this approach.
Most of the emission data on which we base the proposed emission
standards were generated from engines using liquefied petroleum gas
(LPG). Operation of natural gas engines is very similar to that of LPG
engines, with one noteworthy exception. Since natural gas consists
primarily of methane, these engines have a much higher level of methane
in the exhaust. Methane generally does not contribute to ozone
formation, so it is often excluded from emission measurements. We
therefore propose to use nonmethane hydrocarbon emissions for
comparison with the standard for natural gas engines. While the
proposed emission standards based on measuring emissions

[[Page 51124]]

in the field depend on total hydrocarbons, this is inconsistent with
the nonmethane hydrocarbon measurements for certifying natural gas
engines. We therefore propose to set a NO_X-only field-
testing standard for natural gas engines instead of a NO_X+HC
standard. Since control of NO_X emissions poses a
significantly greater challenge for natural gas engines, certification
testing should provide adequate assurance that these engines have
sufficiently low nonmethane hydrocarbon emissions. We request comment
on this proposed arrangement of emission standards and testing
requirements to account for methane.
2. Could I Average, Bank, or Trade Emission Credits?
As described in Section III, we often give manufacturers the option
of showing they meet emission standards using an emission-credit
program that allows them to introduce a mix of technologies with
average emission levels below the standards. The emission standards for
Large SI engines proposed above are based on full compliance by all
engine families without averaging, banking and trading at
certification. (Note the separate discussion of averaging, banking, and
trading that applies to testing in-use engines in Section IV.D.4.) In
determining whether we should adopt an averaging, banking, and trading
program in connection with promulgating a standard, we need to consider
whether the adoption of such a program would affect the determination
of what emission standards would ``achieve the greatest degree of
emission reduction achievable through [available technology]
. . .
giving appropriate consideration to the cost of applying such
technology within the period of time available to manufacturers and to
noise, energy, and safety factors associated with the application of
such technology''. The standards we are proposing for Large SI engines
reflect our assessment of these statutory factors in the absence of an
ABT program for these engines. If, after notice and comment, we decide
that an ABT program is appropriate, we will need to reassess the
appropriate level of these standards considering the statutory factors.
The emission data described in the Draft Regulatory Support Document
show that while all engines in this category are likely to be able to
meet the proposed standard, some engines in this category are likely to
be capable of operating at a level below the level of the proposed
emission standards. Incorporating an emission-credit program without
adjusting the emission standards would allow manufacturers to produce
some engines that have emissions that are higher than the levels we
believe are capable of being met by all engines in the category. Given
the emission data supporting the proposed emission standards, we
believe that we would therefore need to set more stringent emission
standards with averaging, banking, and trading provisions to achieve
the ``greatest degree of emission reduction'' from these engines.
We request comment on including provisions to average, bank, and
trade emission credits. We believe the appropriate standards with an
emission-credit program would be 2.7 g/kW-hr (2.0 g/hp-hr) for
HC+NO_X emissions and 2.7 g/kW-hr (2.0 g/hp-hr) for CO
emissions. See the Draft Regulatory Support Document for further
discussion of this issue. Making the comparable adjustments to the
field-testing measurements described in Section IV.D.5 leads to field-
testing standards under an emission-credit program of 3.8 g/kW-hr (2.8
g/hp-hr) for HC+NO_X emissions and 4.0 g/kW-hr (3.0 g/hp-hr)
for CO emissions.
In addition, considering the frequent use of Large SI engines in
enclosed areas, we may need to cap Family Emission Levels sufficiently
to address concerns for exposure to elevated concentrations of CO, NO,
and NO2 emissions. The Draft Regulatory Support Document shows that
emission levels of 3.4 g/kW-hr for HC+ NO_X and for CO appear
to be appropriate limits related to a scenario of exposure in enclosed
or other limited-air flow areas. We also believe that there is no type
of engine or application in the Large SI field that cannot accommodate
the basic technologies associated with these emission levels, so this
emission level would serve as an appropriate cap on Family Emission
Levels in an emission-credit program for both HC+NO_X and CO
emissions. We request comment on these issues.
For additional, general provisions of an emission-credit program,
see the proposed regulation language in part 1051, subpart H for
recreational vehicles. We request comment on all aspects of averaging,
banking, and trading for Large SI engines. Commenters should address
appropriate emission levels for the potential mix of technologies under
consideration. This should include a discussion of any technology or
market constraints (or incentives) that would lead manufacturers to
differentiate their engines with varying degrees of emission control.
In addition, we request comment on the possibility that small-volume
manufacturers with a limited product offering will be disadvantaged by
an emission-credit program that may give larger companies a competitive
advantage in selected markets.
As an alternative to a program of calculating emission credits for
averaging, banking, and trading, we are proposing a simpler approach to
help manufacturers transition to the proposed 2007 emission standards
(see 40 CFR 1048.145 of the proposed regulations). Under this ``family
banking'' concept, we would allow manufacturers to certify an engine
family early. For each year of certifying an engine family early, the
manufacturer would be able to delay certification of a smaller engine
family by one year. This would be based on the actual sales of the
early family and the projected sales volumes of the late family; this
would require no calculation or accounting of emission credits. The
manufacturer would verify that actual sales are consistent with
projected sales at the end of the model year.
3. Is EPA Proposing Blue Sky Standards for These Engines?
We are proposing a staggered Blue Sky approach aligned with the
introduction of new emission standards. In the 2003 model year,
manufacturers could certify their engines to the requirements that
apply starting in 2004 to qualify for the Blue Sky designation. Since
manufacturers are producing engines with emission-control technologies
starting in 2001, these engines would be available to customers outside
of California desiring emission reductions or fuel-economy
improvements. We request comment on whether we should make this
available to 2002 model year engines. Similarly, for 2003 through 2006
model years, manufacturers could certify their engines to the
requirements that start to apply in 2007. Finally, we propose to set a
target of 1.3 g/kW-hr (1.0 g/hp-hr) HC+NO_X and 3.4 g/kW-hr
(2.5 g/hp-hr) CO as a qualifying level for Blue Sky Series engines for
all model years. The corresponding field-testing standards for Blue Sky
Series engines would be 1.8 g/kW-hr (1.4 g/hp-hr) HC+NO_X and
5.0 g/kW-hr (3.8 g/hp-hr) CO. We request comment on the level of the
voluntary standards starting in 2007. We also request comment on the
advantages of additional labeling provisions that would advertise or
promote these low-emission products.
4. What Durability Provisions Apply?
a. Useful life. We propose to set a minimum useful life period of
seven

[[Page 51125]]

years or until the engine accumulates at least 5,000 operating hours,
whichever occurs first. This figure, which California ARB also adopted,
represents an operating period that is common for Large SI engines
before they undergo rebuild. This also reflects a comparable degree of
operation relative to the useful life values of 100,000 to 150,000
miles that apply to automotive engines (assuming an average driving
speed of 20 to 30 miles per hour).
Some engines are designed for operation in severe-duty applications
with a shorter expected lifetime. Concrete saws in particular undergo
accelerated wear as a result of operating in an environment with high
concentrations of highly abrasive, airborne concrete dust particles. In
a previous rulemaking, we adopted a provision for a manufacturer to ask
us to approve a useful life shorter than the minimum period that would
otherwise apply. This shortened useful life would be based on
information from manufacturers showing how long their engines typically
operated. Extending that provision to Large SI engines would depend on
a manufacturer including only engines from severe-duty applications in
a given engine family. The likely practical benefits of segregating
severe-duty engines would be to shorten the period for establishing
deterioration factors and to avoid in-use testing on engines that are
no longer meeting emission standards. We request comment on the
appropriate approach to useful life values for severe-duty and other
Large SI engines. We also request comment on any other limitations on
manufacturers' ability to meet the proposed requirements that may be
particular to severe-duty engines.
b. Warranty. We are proposing that manufacturers provide an
emission-related warranty for at least the first half of an engine's
useful life (in operating hours) or 3 years, whichever comes first.
These periods must be longer if the manufacturer offers a longer
mechanical warranty for the engine or any of its components; this
includes extended warranties that are available for an extra price. In
addition, we are proposing the warranty provisions adopted by
California ARB for high-cost parts. For emission-related components
whose replacement cost is more than about $400, we are proposing a
minimum warranty period of at least 70 percent of the engine's useful
life (in operating hours) or 5 years, whichever comes first. See
Sec. 1048.120 for a description of which components are emission-
related. We request comment on these proposed warranty provisions.
c. Maintenance instructions. We are proposing to apply minimum
maintenance intervals much like those established by California ARB for
Large SI engines. The minimum intervals define how much maintenance a
manufacturer may specify to ensure that engines are properly maintained
for staying within emission standards. We propose to allow
manufacturers to schedule maintenance on the following components after
4,500 hours of use: catalysts, fuel injectors, electronic controls and
sensors, and turbochargers.
There are two areas of maintenance for which we are especially
concerned. The first is related to the durability of oxygen sensors. We
recognize that if an oxygen sensor degrades or fails, emissions can
increase significantly. It is important to create a strong incentive to
use the most durable oxygen sensors available. That is why we are
proposing to apply the 4,500-hour minimum interval to scheduled
maintenance of oxygen sensors. We are also proposing diagnostic
requirement to ensure that prematurely failing oxygen sensors are
detected and replaced on an as-needed basis. If operators would fail to
replace oxygen sensors after a fault signal, we would not consider that
engine to be properly maintained. This would invalidate the emission-
related warranty and make the engine ineligible for manufacturer in-use
testing. We request comment on this approach.
Our second area of concern is related to the potential need to
clean LPG fuel mixers. We are aware that for some existing designs,
fuel mixers can become fouled to the point that they are unable to
achieve proper control of air-fuel ratios. When this occurs, it can
usually be remedied by simply removing the mixer and cleaning it.
Chapter 4 of the Draft Regulatory Support Document describes this in
further detail, including emission test data showing that fuel systems
can be quite tolerant of deposits from fuel impurities. We request
comment on (1) additional test data showing an effect of mixer fouling
on emissions, (2) whether we should add mixer cleaning as a possible
scheduled-maintenance item, and (3) how manufacturers could ensure that
operators of in-use engines would do this cleaning.
d. Deterioration factors. We are proposing an approach that gives
manufacturers wide discretion to establish deterioration factors for
Large SI engines. The general expectation is that manufacturers will
rely on emission measurements from engines have operated for an
extended period, either in field service or in the laboratory. The
manufacturer should do testing as needed to be confident that their
engines will meet emission standards under the in-use testing program.
We expect to review deterioration factors to ensure that the projected
deterioration is consistent with any engine testing under in-use
testing program. In the first two or three years of certification, we
would rely on manufacturers' technical judgment (instead of results
from in-use testing) to appropriately estimate deterioration factors to
protect themselves from the risk of noncompliance.
e. In-use fuel quality. Gasoline used in industrial applications is
generally the same as that used for automotive applications.
Improvements that have been made to highway-grade gasoline therefore
carry over directly to nonroad markets. This helps manufacturers be
sure that fuel quality will not degrade an engine's emission-control
performance after several years of sustained operation.
In contrast, there are no enforceable industry or government
standards for fuel quality for LPG. As a result, LPG composition can
vary widely. Limited testing data show that this varying fuel quality
has a relatively small direct effect on emissions from a closed-loop
engine with a catalyst. The greater concern is that fuel impurities and
heavy-end hydrocarbons may cause an accumulation of deposits that can
prevent an emission-control system from functioning properly. While an
engine's feedback controls can compensate for some restriction in air-
and fuel-flow, deposits may eventually prevent the engine from
accurately controlling air-fuel ratios at stoichiometry. In any case, a
routine cleaning step should remove deposits and restore the engine to
proper functioning. We are aware of no systematic study of the effect
of these deposits on in-use emissions, either from highway or from
nonroad engines.
We request comment on the following things with respect to the
quality of in-use LPG:

--The degree to which fuel quality affects emission durability, with
supporting data.
--The ability of the proposed diagnostic requirements to alert the
operator to the need for maintenance when the engine is no longer able
to control air-fuel ratios at stoichiometry.
--The need for manufacturers to specify cleaning of fuel systems as
part of critical emission-related maintenance, as described above.
--The possibility of applying engine technology to prevent fuel-related
deposits.

[[Page 51126]]

--The potential to develop an industry-wide specification for in-use
LPG motor fuels.
--The costs and benefits of fuel additives designed to prevent fuel-
related deposits and how we could ensure that in-use fuels consistently
include any appropriate additives.
5. Are There Other Requirements for Large SI Engines?
a. Crankcase emissions. Due to blowby of combustion gases and the
reciprocating action of the piston, exhaust emissions can accumulate in
the crankcase. Uncontrolled engine designs route these vapors directly
to the atmosphere. We have long required that automotive engines
prevent emissions from the engine's crankcase. Manufacturers generally
do this by routing crankcase vapors through a valve into the engine's
air intake system. We propose to require manufacturers to prevent
crankcase emissions from Large SI engines. Since automotive engine
blocks are already tooled for closed crankcases, the cost of adding a
valve for positive-crankcase ventilation is very small. See the Draft
Regulatory Support Document for further discussion of the costs and
emission reductions associated with crankcase emissions.
b. Diagnosing malfunctions. We propose to require that Large SI
engines diagnose malfunctioning emission-control systems starting with
the 2007 model year (see Sec. 1048.110). Three-way catalyst systems
with closed-loop fueling control work well only when the air-fuel
ratios are controlled to stay within a narrow range around
stoichiometry.\125\ Worn or broken components or drifting calibrations
over time can prevent an engine from operating within the specified
range. This increases emissions and can significantly increase fuel
consumption and engine wear. The operator may or may not notice the
change in the way the engine operates.
---------------------------------------------------------------------------

\125\ Stoichimetry is the proportion of a mixture of air and
fuel such that the fuel is fully oxidized with no remaining oxygen.
For example, stoichiometric combustion in gasoline engines typically
occurs at an air-fuel mass ratio of about 14.7.
---------------------------------------------------------------------------

The proposed diagnostic requirement focuses solely on maintaining
stoichiometric control of air-fuel ratios. This kind of design would
detect problems such as broken oxygen sensors, leaking exhaust pipes,
fuel deposits, and other things that would require maintenance to keep
the engine at the proper air-fuel ratio.
Some companies are already producing engines with diagnostic
systems that check for consistent air-fuel ratios. Their initiative
supports the idea that diagnostic monitoring provides a mechanism to
help keep engines tuned to operate properly, with benefits for both
controlling emissions and maintaining optimal performance. There are
currently no inspection and maintenance programs for nonroad engines,
so the most important variable in making the emission control and
diagnostic systems effective is in getting operators to repair the
engine when the diagnostic light comes on. This calls for a relatively
simple design to avoid false failures as much as possible. The proposed
diagnostic requirements therefore focus on detecting inappropriate air-
fuel ratios, which is the most likely failure mode for three-way
catalyst systems. We propose to specify that the malfunction-indicator
light should go on when an engine operates for a full minute without
reaching a stoichiometric air-fuel ratio. If this specified time is too
long, we could be allowing extended open-loop operation with increased
emission levels. We request comment on whether this approach is
appropriate and whether this one-minute period should be longer or
shorter to provide timely detection without causing false failures. In
addition, we request comment on the appropriateness of other
malfunction indicators, such as a measuring the frequency of crossing
stoichiometry or monitoring the voltage range of oxygen sensors.
Some natural gas engines may meet standards with lean-burn designs
that never approach stoichiometric combustion. While manufacturers may
design these engines to operate at specific air-fuel ratios, catalyst
conversion is not as sensitive to air-fuel ratio as with stoichiometric
designs. We request comment on whether these engines should show a
malfunction condition when departing from a targeted air-fuel ratio, or
whether some other parameters would more appropriately detect for any
possible failure modes.
For cars and light-duty trucks, our diagnostic system requirements
call for monitoring of misfire and reduction in catalyst conversion
efficiency. We are not proposing these additional diagnostic features
for nonroad Large SI engines. Requiring misfire and catalyst conversion
monitoring, which are more difficult to detect, would require extensive
development effort to define appropriate failure thresholds and for
manufacturers to design systems to avoid false failures and false
positive detection. In the context of this rulemaking, which proposes
initial standards for nonroad Large SI engines, we believe it is
important for manufacturers to design engines for low emissions before
taking the step of designing a thorough, complex diagnostic system. We
believe that monitoring air-fuel ratio will achieve the majority of the
benefit available from diagnostic systems at a reasonable cost.
Moreover, without a corresponding inspection-and -maintenance program,
operators are most likely to respond to diagnostic warnings with a
system that is clear and simple.
An example illustrates a typical scenario. One forklift operator
driving an LPG-powered lift truck with three-way catalyst and closed-
loop electronic controls noticed that he was able to run two hours
shorter than usual on a standard tank of fuel. Since power
characteristics were not noticeably affected, the operator had done no
maintenance or investigation to correct the problem. Simply replacing
the defective oxygen sensor restored the engine to its original level
of performance (for fuel consumption and emission control). A
diagnostic light would serve to alert operators that the engine needs
attention and would provide help in identifying any specific parts
causing the problem. Since the basic function of a three-way catalyst
system is generally consistent with power and fuel-economy
considerations, operators would have good reason to respond to a
diagnostic light.
The automotive industry has developed a standardized protocol for
diagnostic systems, including hardware specifications, and uniform
trouble codes. Some of these will apply to nonroad engines, but some
will not. In the proposed regulations we reference standards adopted by
the International Organization for Standardization (ISO) for automotive
systems. If these standards do not apply to the simpler diagnostic
design proposed for Large SI engines, we encourage engine manufacturers
to cooperate with each other and with other interested companies to
develop new standards specific to nonroad engines.
As described in the proposed regulatory text, the malfunction light
should go on when the system detects a malfunction and must stay on
until the engine is serviced or until the engine returns to consistent,
normal operation. Stored diagnostic trouble codes would identify as
closely as possible the cause of the malfunction, which could then be
read by any qualified technician.
We request comment on these proposed diagnostic system
requirements.

[[Page 51127]]

c. Evaporative emissions. Evaporative emissions occur when fuel
evaporates and is vented into the atmosphere. They can occur while an
engine or vehicle is operating and even while it is not being operated.
Among the factors that affect evaporative emissions are:
Fuel metering (fuel injectors or carburetor).
The degree to which fuel permeates fuel lines and fuel
tanks.
Proximity of the fuel tank to the exhaust system or other
heat sources.
Whether the fuel system is sealed and the pressure at
which fuel vapors are ventilated.
In addition, some gasoline fuel tanks may be exposed to heat from
the engine compartment and high-temperature surfaces such as the
exhaust pipe. In extreme cases, fuel can start boiling, producing very
large amounts of gasoline vapors vented directly to the atmosphere.
Evaporative emissions from Large SI engines and the associated
equipment represent a significant part of their overall hydrocarbon
emissions. The magnitude of evaporative emissions varies widely
depending on the engine design and application. LPG-fueled equipment
generally has very low evaporative emissions because of the tightly
sealed fuel system. At the other extreme, carbureted gasoline-fueled
equipment can have high rates of evaporation. Southwest Research
Institute measured emissions from several gasoline-fueled Large SI
engines and found them to vary from about 12 g/day up to almost 100 g/
day.\126\ This study did not take into account the possibility of
unusually high fuel temperatures during engine operation, as described
further below.
---------------------------------------------------------------------------

\126\ ``Measurement of Evaporative Emissions from Off-Road
Equipment,'' by James N. Carroll and Jeff J. White, Southwest
Research Institute (SwRI 08-1076), November 1998, Docket A-2000-01,
document II-A-10.
---------------------------------------------------------------------------

We are proposing to require basic measures to reduce evaporative
emissions from gasoline-fueled Large SI engines. The usual approach to
regulating emissions from nonroad and other mobile engines is to define
a measurement procedure and adopt numerical limit values (or standards)
that together determine a minimum required level of performance.
Manufacturers are then free to use any kind of technology to meet these
performance standards.
Since the Act directs us to first consider regulating nonroad
engines with standards similar to those that apply to motor vehicles,
we must consider test-based evaporative emission standards that would
be comparable to those for automobiles. However, we have practical
concerns with requiring that approach as the only option for
manufacturers. These concerns relate primarily to the nonintegrated
nature of these industries and the wide variety of applications in
which the engines are used. Some manufacturers could face difficulties
certifying to specific numerical emission levels because of the large
variation in fuel system components needed to fit the many varied kinds
of equipment. While a test-based standard may be feasible, we believe
we should allow the use of other cost-effective approaches that could
be more appropriate for this industry.
We propose to adopt an evaporative emission standard of 0.2 grams
per gallon of fuel tank capacity for heating a fuel tank from 72 deg.
to 96 deg. F. We further propose that manufacturers can rely on a
design-based certification instead of measuring emissions by adopting
one of the designs described in this paragraph. We have identified four
technologies that would adequately prevent evaporative emissions to
show compliance with the proposed evaporative emission standard. First,
pressurized fuel tanks control evaporative emissions by suppressing
vapor generation. In its standards for industrial trucks operating in
certain environments, Underwriters Laboratories requires that trucks
use self-closing fuel caps with tanks that stay sealed to prevent
evaporative losses; venting is allowed for positive pressures above psi
or for vacuum pressures of at least 1.5 psi.\127\ Any Large SI engines
or vehicles operating with these pressures would satisfy the
certification requirements. Second, for applications where such high
fuel tank pressures are undesirable, manufacturers could instead rely
on an air bladder inside the fuel tank that changes in volume to keep
the system in equilibrium at atmospheric pressure.\128\ Third, an
automotive-type system that stores fuel tank vapors for burning in the
engine would be another alternative technology. Finally, collapsible
bladder tanks, which change in volume to prevent generation of a vapor
space or vapor emissions, are also commercially available. Also,
similar to the Underwriters Laboratories' requirement, we are proposing
that manufacturers must use self-closing or tethered fuel caps to
ensure that fuel tanks designed to hold pressure are not inadvertently
left exposed to the atmosphere. Section 1048.105 of the proposed
regulations describes these design specifications in greater detail. We
request comment on these approaches and on whether we should consider
tank insulation as an alternative or complementary strategy for meeting
the proposed requirements on a design basis.
---------------------------------------------------------------------------

\127\ ``Industrial Trucks, Internal Combustion Engine-Powered,''
UL558, ninth edition, June 28, 1996, paragraphs 26.1 through 26.4,
Docket A-2000-01, document II-A-28. See Section XI.E for our
consideration of incorporating the UL requirements into our
regulations by reference.
\128\ ``New Evaporative Control System for Gasoline Tanks,'' EPA
Memorandum from Charles Moulis to Glenn Passavant, March 1, 2001,
Docket A-2000-01, document II-B-16.
---------------------------------------------------------------------------

In addition, we propose to require that engine manufacturers use
(or specify that equipment manufacturers installing their engines use)
fuel lines meeting the industry performance standard for permeation-
resistant fuel lines developed for motor vehicles.\129\ While metal
fuel lines do not have problems with permeation, manufacturers should
use discretion in selecting materials for grommets and valves
connecting metal components to avoid high-permeation materials.
Evaporative emission standards for motor vehicles have led to the
development of a wide variety of permeation-resistant polymer
components.
---------------------------------------------------------------------------

\129\ SAE J2260 ``Nonmetallic Fuel System Tubing with One or
More Layers,'' November 1996.
---------------------------------------------------------------------------

Finally, manufacturers can take steps to reduce fuel temperatures
during operation. The use of fuel injection and the associated
recirculating fuel lines and in-tank fuel pumps may even increase the
heat load into the fuel tank, which would tend to increase emission
rates generally and may increase the occurrence of fuel boiling. The
Underwriters Laboratories specification for forklifts attempts to
address this concern through a specified maximum fuel temperature, but
the current limit does not prevent fuel boiling.\130\ We are proposing
a standard that prohibits fuel boiling during continuous operation at
30 deg. C (86 deg. F). Engine manufacturers would have to incorporate
designs that reduce the heat load to the fuel tank to prevent boiling.
For companies that sell loose engines, this may involve instructions to
equipment manufacturers to help ensure, for example, that fuel tank
surfaces are exposed to ambient air rather than to exhaust pipes or
direct engine heat. Engine manufacturers may specify a maximum fuel
temperature for the final installation. Such a temperature limit should
be well below 53 deg. C (128 deg. F), the

[[Page 51128]]

temperature at which summer-grade gasoline (9 RVP) typically starts
boiling.
---------------------------------------------------------------------------

\130\ UL558, paragraph 19.1.1, Docket A-2000-01, document II-A-
28.
---------------------------------------------------------------------------

An additional source of evaporative emissions is from carburetors.
Carburetors often have high hot soak emissions (immediately after
engine shutdown). We expect manufacturers to convert carbureted designs
to fuel injection as a result of the proposed exhaust emission
standards. While we are not proposing to mandate this technology, we
believe the need to reduce exhaust emissions will cause engine
manufacturers to use fuel injection on all gasoline engines. This
change alone would eliminate most hot soak emissions. We request
comment on whether the procedure described in the previous paragraphs
would require fuel injection. In addition, we request comment on the
possibility of meeting the 2007 exhaust emission standards with
carbureted engines.
Engine manufacturers using design-based certification would need to
describe in the application for certification the selected design
measures and specifications to address evaporative losses from
gasoline-fueled engines. For loose-engine sales, this would include
emission-related installation instructions that the engine manufacturer
would give to equipment manufacturers.
With the ready availability of automotive technology and the
development effort already in place to meet Underwriters Laboratories'
requirements, we believe the proposed evaporative-control provisions
would not pose a major development burden in most cases. We expect
manufacturers generally to meet the proposed evaporative requirements
with low-cost, off-the-shelf technologies. Individual engines may need
somewhat more development effort to ensure compliance, but the hardware
and testing costs would be minimal. We estimate an average cost of
about $10 per engine for those engines that would be subject to
evaporative-emission standards. Once this program is fully phased in,
we estimate over 7,500 tons of HC reductions annually. See the Draft
Regulatory Support Document for further information about the estimated
costs and benefits of evaporative emission controls.
Reducing evaporative losses would not only provide health and
safety advantages, but would contribute to overall fuel savings from
Large SI engines. We request comment on the proposed measures to
control evaporative emissions, including the potential cost and
effectiveness of (1) an evaporative emission standard at 0.2 g/gal of
fuel, (2) the optional design standards, and (3) the proposed fuel-line
and fuel-temperature requirements. We also request comment on any
additional or complementary approaches.

D. Proposed Testing Requirements and Supplemental Emission Standards

1. What Duty Cycles Would Be Used To Measure Emissions?
For 2004 through 2006 model years, we are proposing to use the same
steady-state duty cycles adopted by California ARB. For most engines
this involves the testing based on the ISO C2 duty cycle, with a
separate duty cycle for constant-speed applications based on the ISO D2
duty cycle. These duty cycles are described further below.
Starting in 2007, we are proposing an expanded set of duty cycles,
again with separate treatment for variable-speed and constant-speed
applications. These duty-cycles are each comprised of three segments:
(1) A warm-up segment, (2) a transient segment, and (3) a steady-state
segment. Each of these segments, described briefly in this section,
include specifications for the speed and load of the engine as a
function of time. Measured emissions during the transient and steady-
state segments must meet the emission standards that apply. In general,
the proposed duty-cycles are intended to include representative
operation from the wide variety of in-use applications. This includes
highly transient low-speed forklift operation, constant-speed operation
of portable equipment, and intermediate-speed vehicle operation.
Chapter 4 of the Draft Regulatory Support Document describes the duty
cycles in greater detail. We request comment on the proposed duty
cycles.
Ambient temperatures in the laboratory must be between 20 deg. and
30 deg. C (68 and 86 deg. F) during duty-cycle testing. This improves
the repeatability of emission measurements when the engine runs through
its prescribed operation. We nevertheless expect manufacturers to
design for controlling emissions under broader ambient conditions, as
described in Section IV.D.5.
The warm-up segment begins with a cold-start. This means that the
engine should be very near room temperature before the test cycle
begins. Once the engine is started, it would be operated over the first
3 minutes of the specified transient duty cycle without emission
measurement. The engine then idles for 30 seconds before starting the
prescribed transient cycle. The purpose of the warm-up segment is to
bring the engine up to normal operating temperature in a standardized
way. The 3-minute warm-up period allows enough time for engine-out
emissions to stabilize, for the catalyst to warm up enough to become
active, and for the engine to start closed-loop operation. This serves
as a defined and achievable target for the design engineer to limit
cold-start emissions to a relatively short period.
The transient segment of the general duty cycle is a composite of
forklift and welder operation. This duty cycle was developed by
selecting segments of measured engine operation from two forklifts and
a welder as they performed their normal functions. This transient
segment captures the wide variety of operation from a large majority of
Large SI engines. Emissions measured during this segment are averaged
over the entire transient segment to give a single value in g/kW.
Steady-state testing consists of engine operation for an extended
period at several discrete speed-load combinations. Associated with
these test points are weighting factors that allow a single weighted-
average steady-state emission level in g/kW. The principal duty cycle
is based on the ISO C2 cycle, which has five modes at various
intermediate speed points, plus one mode at rated speed and one idle
mode. The combined intermediate-speed points at 10, 25, and 50 percent
account for over 70 percent of the total modal weighting. While any
steady-state duty cycle is limited in how much it can represent
operation of engines that undergo transient operation, the distribution
of the C2 modes and their weighting values aligns significantly with
expected and measured engine operation from Large SI engines. In
particular, these engines are generally not designed to operate for
extended periods at high-load, rated speed conditions. Field
measurement of engine operation shows, however, that forklifts operate
extensively at lower speeds than those included in the C2 duty cycle.
While we believe the test points of the C2 duty cycle are
representative of engine operation from many applications of Large SI
engines, supplementing the steady-state testing with a transient duty
cycle is necessary to adequately include engine operation
characteristic of what occurs in the field.
Engines such as generators, welders, compressors, and pumps are
governed to operate only at a single speed with varying loads. We are
proposing a combination of transient and steady-state testing that
applies specifically to constant-speed engines. The transient duty-
cycle segment includes 20 minutes of engine operation based on measured

[[Page 51129]]

welder operation. We expect to propose this same transient duty cycle
for constant-speed nonroad diesel engines. Manufacturers would also
test constant-speed Large SI engines with steady-state operation based
on the ISO D2 duty cycle, which specifies engine operation at rated
speed with five different load points. This same steady-state duty
cycle applies to constant-speed, nonroad diesel engines. Emission
values measured on the D2 duty cycle are treated the same as values
from the C2 duty cycle; the same numerical standards apply to both
cycles. Manufacturers selling engines for both constant-speed and
variable-speed applications would omit the constant-speed transient
test, since that operation is included in the general transient test.
We are concerned that engines certified with the C2 duty cycle may
be installed in constant-speed applications; or, similarly that engines
certified with the D2 duty cycle may be installed in variable-speed
applications. Since the C2 cycle includes very little operation at
rated speed, it is not effective in ensuring control of emissions for
constant-speed engines. The D2 cycle is even less capable of predicting
emission performance from variable-speed engines. To address this, we
are proposing that manufacturers routinely test engines on both the C2
and D2 duty cycles.\131\ Manufacturers selling only a variable-speed or
only constant-speed engines in an engine family would be allowed to
omit testing with the duty cycle that would not apply. With a more
limited certification, however, we would require the manufacturer to
add information to the engine label and any emission-related
installation instructions to clarify that the engine has a limited
certification. We request comment on this approach to variable- and
constant-speed engines.
---------------------------------------------------------------------------

\131\ It would not be necessary to repeat the warm-up and
transisent segments for additional steady-state duty cycles.
---------------------------------------------------------------------------

Some diesel-derived engines operating on natural gas with power
ratings up to 1,500 or 2,000 kW may be covered by the proposed emission
standards. Engine dynamometers with transient-control capabilities are
generally limited to testing engines up to 500 or 600 kW. We propose at
this time to waive emission standards and testing requirements related
to transient duty cycles for engines above 560 kW. We would likely
review this provision for Large SI engines once we have reached a
conclusion on the same issue for nonroad diesel engines. We would
expect to treat both types of engines the same way. Note that the
field-testing emission standards still apply to engines that don't
certify to transient duty-cycle standards.
2. What Fuels Would Be Used During Emission Testing?
For gasoline-fueled Large SI engines, we are proposing to use the
same specifications we have adopted for testing gasoline-fueled highway
vehicles and engines. This includes the revised specification to cap
sulfur levels at 80 ppm (65 FR 6698, February 10, 2000).
For LPG and natural gas, we are proposing to use the same
specifications adopted by California ARB. We understand that in-use
fuel quality for LPG and natural gas varies significantly in different
parts of the country and at different times of the year. Not all in-use
fuels outside California meet California ARB specifications for
certification fuel, but fuels meeting the California specifications are
nevertheless widely available. Test data show that LPG fuels with a
much lower propane content have only slightly higher NO_X and
CO emissions (see Chapter 4 of the Draft Regulatory Support Document
for additional information). These data support our belief that engines
certified using the specified fuel will achieve the desired emission
reduction for a wide range of in-use fuels.
Unlike California ARB, we propose to apply the fuel specifications
to testing only for emission measurements, not to service accumulation.
We propose to allow service accumulation between emission tests with
certification fuel or any commercially available fuel of the
appropriate type. We would similarly allow manufacturers to choose
between certification fuel and any commercial fuel for in-use
measurements to show compliance with field-testing emission standards.
We request comment on appropriate fuel specifications for all types
of engine testing.
3. Are There Proposed Production-Line Testing Provisions for Large SI
Engines?
The provisions described in Section III.C.4 apply to Large SI
engines. These proposed requirements are consistent with those adopted
by California ARB. One new issue specific to Large SI engines relates
to the duty cycles for measuring emissions from production-line
engines.
For routine production-line testing, we propose to require emission
measurements only with the steady-state duty cycles used for
certification. Due to the cost of sampling equipment for transient
engine operation, we are not proposing to require routine transient
testing of production-line engines. We believe that steady-state
emission measurements will give a good indication of manufacturers'
ability to build engines consistent with the prototypes on which their
certification data are based. We also propose, however, to reserve the
right to direct a manufacturer to measure emissions with a transient
duty cycle if we believe it is appropriate. One indication of the need
for this transient testing would be if steady-state emission levels
from production-line engines are significantly higher than the emission
levels reported in the application for certification for that engine
family. For manufacturers with the capability of measuring transient
emission levels at the production line, we would recommend doing
transient tests to better ensure that in-use tests will not reveal
problems in controlling emissions during transient operation.
Manufacturers would not need to make any measurements to show that
production-line engines can meet field-testing emission standards.
We request comment on all aspects of the proposed production-line
testing requirements, including engine sampling rates and options for
using alternative testing methods.
4. Are There Proposed In-Use Testing Provisions for Large SI Engines?
While the certification and production-line compliance requirements
are important to ensure that engines are designed and produced in
compliance with established emission limits, there is also a need to
confirm that manufacturers build engines with sufficient durability to
meet emission limits as they age in service. Consistent with the
California ARB program, we are proposing to require engine
manufacturers to conduct emission tests on a small number of field-aged
engines to show they meet emission standards.
Under the proposed program, we may generally select up to 25
percent of a manufacturer's engine families in a given year to be
subject to in-use testing (see Table IV.D-1). Most companies would need
to test at most one engine family per year. Manufacturers may conduct
in-use testing on any number of additional engine families at their
discretion. We request comment on this maximum rate of testing engines
under the proposed in-use testing program.

[[Page 51130]]

Table IV.D-1.--Maximum In-Use Testing Rate
------------------------------------------------------------------------
Maximum
number of
families
Number of engine families for a manufacturer subject to
in-use
testing
each year
------------------------------------------------------------------------
1.......................................................... 1
2.......................................................... 1
3.......................................................... 1
4.......................................................... 1
5.......................................................... 1
6.......................................................... 1
7.......................................................... 1
8.......................................................... 2
9.......................................................... 2
10......................................................... 2
11......................................................... 2
12......................................................... 3
------------------------------------------------------------------------

We are also proposing that manufacturers in unusual circumstances
have the ability to develop an alternate plan to fulfill any in-use
testing obligations, consistent with a similar program we have adopted
for outboard and personal watercraft marine engines. These
circumstances include total sales for an engine family below 200 per
year, installation only in applications where testing is not possible
without irreparable damage to the vehicle or engine, or any other
unique feature that prevents full emission measurements. We request
comment on these provisions.
While this flexibility for alternate measurements would be
available to small-volume manufacturers, we also request comment on
applying in-use testing requirements to very small-volume engine
families in general. While the proposed regulations would allow us to
select an engine family every year from an engine manufacturer, there
are several reasons why small volume manufacturers could expect a less
demanding approach. These manufacturers may have only one or two engine
families. If a manufacturer shows that an engine family meets emission
standards in an in-use testing exercise, that could provide adequate
data to show compliance for that engine family for a number of years,
provided the manufacturer continues to produce those engines without
significantly redesigning them in a way that could affect their in-use
emissions performance and that we do not have other reason to suspect
noncompliance. Also, where we had comfort that a manufacturer's engines
were likely in good in-use compliance, we would generally take the
approach of selecting engine families based on some degree of
proportionality. To the extent that manufacturers produce a smaller
than average proportion of engines, they could expect that we would
select their engine families less frequently, especially if other
available data pointed toward clear in-use compliance.
We are also proposing that manufacturers in unusual circumstances
have the ability to develop an alternate plan to fulfill any in-use
testing obligations. These include total sales for an engine family
below 200 per year, installation only in applications where testing is
not possible without irreparable damage, or any other unique feature
that prevents full emission measurements. We request comment on these
provisions. While this flexibility would be available to small-volume
manufacturers, we also request comment on applying in-use testing
requirements to these companies in general. While the proposed
regulations would allow us select an engine family every year from an
engine manufacturer, there are reasons why these companies could expect
a less demanding approach. First, to avoid unfair treatment of
individual manufacturers, we would generally take the approach of
selecting engine families based on some degree of proportionality. To
the extent that manufacturers produce a smaller than average proportion
of engines, they could expect that we would select their engine
families less frequently. In addition, our experience in implementing a
comparable testing program for recreational marine engines provides a
history of how we implement in-use testing requirements.
Engines can be tested one of two ways. First, manufacturers can
remove engines from vehicles or equipment and test the engines on a
laboratory dynamometer using certification procedures. For 2004 through
2006 model year engines, this would be the same steady-state duty cycle
used for certification; manufacturers may optionally test engines on
the dynamometer under transient operating conditions. For 2007 and
later model year engines, manufacturers must test engines using both
steady-state and transient duty cycles, as in certification.
Second, manufacturers may use the proposed equipment and procedures
for testing engines without removing them from the equipment (referred
to in this document as field-testing). See Section IV.D.5 for a more
detailed description of how to measure emissions from engines during
normal operation in the field. Since engines operating in the field
cannot be controlled to operate on a specific duty cycle, compliance
would be demonstrated by comparing the measured emission levels to the
proposed field-testing emission standards, which would have higher
numerical value to account for the possible effects of different engine
operation. Because the engine operation can be so variable, however,
engines tested to show compliance only with the field-testing emission
standards would not be eligible to participate in the in-use averaging,
banking, and trading program (described below).
We could give directions to include specific types of normal
operation to confirm that engines are controlling emissions in real
operation. For example, for testing to show compliance with field-
testing emission standards, we may identify specific types of operation
on specific days or times to sample emissions, as long as these fall
within the range of normal operation for the application. Dynamometer
testing might include operation over a torque-speed trace measured from
any appropriate equipment. If we don't provide specific direction,
manufacturers would use their discretion to show that engines comply
with the field-testing standards, much like for certification (see
Section IV.D.5).
Along with the in-use testing program, we are proposing an in-use
credit program designed to reduce compliance cost without reducing
environmental benefits. The program would provide manufacturers with
flexibility in addressing potential in-use noncompliance in a way that
we agree would avoid the need for a determination of nonconformity
under Clean Air Act section 207(c), and thereby avoid a recall.
Participation in this program would be voluntary.
The flexibility of the proposed in-use credit program is
appropriate given the particular circumstances of the Large SI engine
industry. For an engine family failing in-use testing, we believe
recalling the nonconforming engines may be particularly burdensome and
impractical for this industry, mainly due to the difficulty of tracking
the nonconforming engines. Recalling the engines would therefore
require substantial resources, yet may not be highly effective in
remedying the excess emissions.
Clean Air Act section 213 requires engines to comply with emission
standards throughout their regulatory useful lives, and section 207
requires a manufacturer to remedy in-use nonconformity when we
determine that a substantial number of properly maintained and used
engines fail to conform with the applicable emission standards (42
U.S.C. 7541). Once we make this determination, recall would be
necessary to remedy the

[[Page 51131]]

nonconformity. However, under these circumstances, where it is expected
that recall would be impractical and largely ineffective, it is
appropriate not to make a determination of substantial nonconformity
where a manufacturer uses emission credits to offset in-use
noncompliance. Thus, under the Clean Air Act, we may choose to make no
section 207(c) determination of substantial nonconformity where an
engine manufacturer uses emission credits to offset any noncompliance
with the statute's in-use performance requirements. Though the language
of section 213(d) is silent on the issue of emission credits, it
generally allows considerable discretion in determining what
modifications to the highway regulatory scheme are appropriate for
nonroad engines.
In-use credits would be based on in-use testing conducted by the
manufacturer. For a given engine family, the in-use compliance level
would be determined by averaging the results from in-use testing
performed for that engine family. If the in-use compliance level is
below the applicable standard, the manufacturer would generate in-use
credits for that engine family. If the in-use compliance level is above
the standard, the engine family would experience a credit deficit.
Manufacturers calculate credits based on the measured emission levels
(when compared with applicable emission standards) and several
additional variables, such as rated power, useful life, and engine
family population. To ensure that emission credits show a real degree
of emission control relative to the emission standard, we are proposing
that emission credits must be based on transient duty-cycle operation
on a dynamometer. An exception would apply for averaging emission
levels from 2004 through 2006 model year engines, where we would allow
for emission credits based on steady-state emission testing.
While we are proposing the in-use credit program adopted by
California ARB, an additional concern relates to the status of emission
credits over the long term. This would be our first step in setting
emission standards for this category of engines, which increases the
uncertainty of setting standards requiring the ``greatest degree of
emission reduction achievable,'' as called for in the Clean Air Act. If
manufacturers are able to use the projected technologies to
consistently achieve emission levels even lower than we require, in-use
testing over several years can lead to a large pool of in-use emission
credits. To avoid making the in-use testing program meaningless for
some engines, especially in the context of a transition to a next tier
of emission standards , we would not intend to use credits older than
three model years in deciding whether to take administrative action
under section 207(c). This should address the concern for accumulating
credits without taking away EPA and the manufacturers' substantial
flexibility to use credits to offset marginally noncompliant engines.
We request comment on all aspects of the proposed in-use testing
requirements.
5. What About Field-Testing Emission Standards and Test Procedures?
To enable field-testing of Large SI engines and to address concerns
for controlling emissions outside of the specific duty cycles proposed
to measure emissions for certification, we are proposing procedures and
standards that apply to a wider range of normal engine operation.
a. What is the field-testing concept? Measuring emissions from
engines in the field as they undergo normal operation while installed
in nonroad equipment addresses two broad concerns. First, this provides
a low-cost method of testing in-use engines. Second, testing has shown
that emissions can vary dramatically under certain modes of operation.
Field-testing addresses this by including emission measurements over
the broad range of normal engine operation. This may include varying
engine speeds and loads according to real operation and may include a
reasonable range of ambient conditions, as described below.
No engine operating in the field can follow a prescribed duty cycle
for a consistent measure of emission levels. Similarly, no single test
procedure can cover all real-world applications, operations, or
conditions. Specifying parameters for testing engines in the field and
adopting an associated emission standard provides manufacturers with a
framework for showing that their engines will control emissions under
the whole range of normal operation in the relevant nonroad equipment.
To ensure that emissions are controlled from Large SI engines over
the full range of speed and load combinations seen in the field, we are
proposing supplemental emission standards that apply more broadly than
the duty-cycle standard. These standards would apply to all regulated
pollutants (NO_X, HC, and CO) under all normal operation
(steady-state or transient). We propose to exclude abnormal operation
(such as very low average power and extended idling time), but not
restrict operation to any specific combination of speeds and loads. In
addition, we are proposing that the field-testing standards would apply
under a broad range of in-use ambient conditions, both to ensure robust
emission controls and to avoid overly restricting the times available
for testing. These provisions are described in detail below.
b. What are the field-testing emission standards? Starting with the
2007 model year, we propose to apply field-testing emission standards
of 4.7 g/kW-hr (3.5 g/hp-hr) for HC+NO_X emissions and 6.7 g/
kW-hr (5.0 g/hp-hr) for CO emissions. As described above for the duty-
cycle standards, we believe manufacturers will be able to use the
additional time beyond 2004 to optimize their designs to control
emissions under the full range of normal in-use operation. As described
in Chapter 4 of the Draft Regulatory Support Document, we believe
manufacturers can achieve these proposed emission standards using
currently available three-way catalysts and electronically controlled
fuel systems.
As described above, we are proposing alternate emission standards
for those engines operating predominantly outdoors. The corresponding
proposed field-testing standards are 1.8 g/kW-hr (1.3 g/hp-hr) for
HC+NO_X emissions and 41 g/kW-hr (31 g/hp-hr) for CO
emissions.
Manufacturers have expressed an interest in using field-testing
procedures before the 2007 model year to show that they can meet
emission standards as part of the in-use testing program. While we are
not proposing specific field-testing standards for 2004 through 2006
model year engines, we are proposing to allow this as an option. In
this case, manufacturers would conduct the field testing as described
here to show that their engines meet the 4 g/kW-hr HC+ NO_X
standard and the 50 g/kW-hr CO standard. This could give manufacturers
the opportunity to do testing at significantly lower cost compared with
laboratory testing. Preliminary certification data from California ARB
show that manufacturers are reaching steady-state emission levels well
below emission standards, so we would expect any additional variability
in field-testing measurements not to affect manufacturers' ability to
meet the same emission standards. We request comment on the need for
and appropriateness of this provision. We also request comment on
whether there should be a separate field-testing standard, higher or
lower than the proposed duty-cycle standards, to provide adequate
assurance that the

[[Page 51132]]

engines operate with the required level of emission control.
These proposed field-testing standards are based on emission data
measured with the same emission-control technology used to establish
the duty-cycle standards. The higher numerical standard for field
testing reflects the observed variation in emissions for varying engine
operation, the projected effects of ambient conditions on the projected
technology, and the accuracy limitations of in-use testing equipment
and procedures. Conceptually, we believe that field-testing standards
should primarily require manufacturers to adjust engine calibrations to
effectively manage air-fuel ratios under varying conditions. The
estimated cost of complying with emission standards includes an
allowance for the time and resources needed for this recalibration
effort (see Section IX.B. for total estimated costs per engine).
EPA generally requires manufacturers to show at certification that
they are capable of meeting requirements that apply for any in-use
testing. This adds a measure of assurance to both EPA and manufacturers
that the engine design is sufficient for any in-use engines to pass any
later testing. For Large SI engines, we are proposing that
manufacturers show in their application for certification that they
meet the field-testing standards. Manufacturers would submit a
statement that their engines will comply with field-testing emission
standards under all conditions that may reasonably be expected to occur
in normal vehicle operation and use. The manufacturer would provide a
detailed description of any testing, engineering analysis, and other
information that forms the basis for the statement. This would likely
include a variety of steady-state emission measurements not included in
the prescribed duty cycle. It may also include a continuous trace
showing how emissions vary during the transient test or it may include
emission measurements during other segments of operation manufacturers
believe is representative of the way their engines normally operate in
the field.
Two additional provisions are necessary to allow emission testing
without removing engines from equipment in the field. We are proposing
to require manufacturers to design their engines to broadcast
instantaneous speed and torque values to the onboard computer. We are
also proposing a requirement to add an emission sampling port
downstream of the catalyst.
The equipment and procedures for showing compliance with field-
testing standards also hold promise to reduce the cost of production-
line testing. Companies with production facilities that have a
dynamometer but no emission measurement capability could use the field-
testing equipment and procedures to get a low-cost, valid emission
measurement at the production line. Manufacturers may choose to use the
cost advantage of the simpler measurement to sample a greater number of
production-line engines. This would provide greater assurance of
consistent emissions performance, but would also provide valuable
quality-control data for overall engine performance. See the discussion
of alternate approaches to production-line testing in Section III.C.4
for more information.
c. What limits are placed on field testing? The field-testing
standards would apply to all normal operation. This could include
steady-state or transient engine operation. Given a set of field-
testing standards, the goal for the design engineer is to ensure that
engines are properly calibrated for controlling emissions under any
reasonably expected mode of engine operation. Engines may not be able
to meet the emissions limit under all conditions, however, so we are
proposing several parameters that would narrow the range of engine
operation that would be subject to the field-testing standards. For
example, emission sampling for field testing would not include engine
starting.
Engines can often operate at extreme engine conditions (summer,
winter, high altitude, etc.). To narrow the range of conditions for the
design engineer, we are proposing to limit emission measurements during
field testing to ambient temperatures from 13 deg. to 35 deg. C
(55 deg. to 95 deg. F), and to ambient pressures from 600 to 775
millimeters of mercury (which should cover almost all normal pressures
from sea level to 7,000 feet above sea level). This allows testing
under a wider range of conditions in addition to helping ensure that
engines are able to control emissions under the whole range of
conditions under which they operate.
We are proposing some additional limits to define ``normal''
operation that could be included in field testing. These restrictions
are intended to provide manufacturers with some certainty about what
their design targets are and to ensure that compliance with the
proposed field-testing standards would be feasible. These restrictions
would apply to both variable-speed and constant-speed engine
applications.
First, measurements with more than 2 minutes of continuous idle
would be excluded. This means that an emission measurement from a
forklift while it idled for 5 minutes would not be considered valid. On
the other hand, an emission measurement from a forklift that idled for
1 minute (continuous or intermittent) and otherwise operated at 40
percent power for several minutes would be considered a valid
measurement. Measurements with in-use equipment in their normal service
show that idle periods for Large SI engines are short, but relatively
frequent. We should therefore not automatically exclude an emission
sample if it includes an idling portion. At the same time, controlling
emissions during extended idling poses a difficult design challenge,
especially at low ambient temperatures. Exhaust and catalyst
temperatures under these conditions can decrease enough that catalyst
conversion rates decrease significantly. Since extended idling is not
an appropriate focus of extensive development efforts at this stage, we
believe the 2-minute threshold for continuous idle appropriately
balances the need to include measurement during short idling periods
with the technical challenges of controlling emissions under difficult
conditions.
Second, we are proposing that the measured power during the
sampling period must be above 5 percent of maximum power for an
emission measurement to be considered valid. Brake-specific emissions
(g/kW-hr) can be very high at low power because they are calculated by
dividing the g/hr emission rate by a very small power level (kW). By
ensuring that brake-specific emissions are not calculated by dividing
by power levels less than 5 percent of the maximum, we can avoid this
problem.
Third, gasoline-fueled engines need to run rich of stoichiometric
combustion during extended high-load operation to protect against
engine failure. This increases HC and CO emissions. We are accordingly
proposing for gasoline-fueled engines that operation at 90 percent or
more of maximum power must be less than 10 percent of the total
sampling time. We would expect it to be uncommon for engine
installations to call for such high power demand due to the shortened
engine lifetime at very high-load operation. A larger engine could
generally produce the desired power at a lower relative load, without
compromising engine lifetime. Alternatively, applications that call for
full-load operation typically use diesel engines. We propose to allow
manufacturers to request a different threshold to allow more open-loop
operation. Before we could approve

[[Page 51133]]

such a request, the engine manufacturer would need to have a plan for
ensuring that the engines in their final installation would not
routinely operate at loads above the specified threshold.
Fourth, as a part of the ``normal operation'' limitation, we are
considering a limit on the frequency of accelerations. Very frequent
acceleration events can make it difficult to consistently get enough
air for combustion. Engine dynamometers also place a practical limit on
the degree of transient operation that can be simulated in the
laboratory. It would not be appropriate to exclude normal driving
patterns, but drawing a line at the upper end of what happens in the
field may be an appropriate constraint for field testing. This would
likely take the form of a maximum frequency of acceleration events
during the emission sampling period. We request comment on defining the
most severe accelerations that we should include in field-testing as
normal operation.
An additional parameter to consider is the minimum sampling time
for field testing. A longer period allows for greater accuracy, due
mainly to the smoothing effect of measuring over several transient
events. On the other hand, an overly long sampling period can mask
areas of engine operation with poor emission-control characteristics.
To balance these concerns, we are proposing a minimum sampling period
of 2 minutes. In other rules for diesel engines, we have allowed
sampling periods as short as 30 seconds. Spark-ignition engines
generally don't have turbochargers and they control emissions by
maintaining air-fuel ratio with closed-loop controls through changing
engine operation. Spark-ignition engines are therefore much less prone
to consistent emission spikes from off-cycle or unusual engine
operation. We believe the 2-minute sampling time requirement will
ensure sufficient measurement accuracy and will allow for more
meaningful measurements from engines that may be operated with very
frequent but brief times at idle. We are not proposing a maximum
sampling time. We would expect manufacturers testing in-use engines to
select an approximate sampling time before measuring emissions. When
selecting an engine family for the in-use testing program, we may add
further direction related to the emission-sampling effort, such as
sampling time or specific types of engine operation.
We request comment on whether these are appropriate constraints on
sampling emissions using field-testing procedures. In particular, we
request comment on whether the limitations described are necessary or
sufficient to target the whole range of normal operation that should be
subject to emission standards.
d. How do I test engines in the field? To test engines without
removing them from equipment, analyzers would be connected to the
engine's exhaust to detect emission concentrations during normal
operation. Exhaust volumetric flow rate and continuous power output
would also be needed to convert the analyzer responses to units of g/
kW-hr for comparing to emission standards. We are proposing to
calculate these values from measurements of the engine intake flow
rate, the exhaust air/fuel ratio and the engine speed, and from torque
information.
Small analyzers and other equipment are already available that
could be adapted for measuring emissions from field equipment. A
portable flame ionization detector could measure total hydrocarbon
concentrations. Methane measurement currently requires more expensive
laboratory equipment that is impractical for field measurements. Field-
testing standards would therefore be based on total hydrocarbon
emissions. A portable analyzer based on zirconia technology measures
NO_X emissions. A nondispersive infrared (NDIR) unit could
measure CO. Emission samples could best be drawn from the exhaust flow
directly downstream of the catalyst material to avoid diluting effects
from the end of the tailpipe. For this reason we request comment on a
requirement for manufacturers to produce all their engines with this
kind of sampling port in the exhaust pipe or at the end of the
catalytic converter. Mass flow rates would also factor into the torque
calculation; this could either be measured in the intake manifold or
downstream of the catalyst.
Calculating brake-specific emissions depends on determining
instantaneous engine speed and torque levels. We therefore propose to
require that manufacturers design their engines to continuously monitor
engine speed and torque. The proposed tolerance for speed measurements,
which is relatively straightforward is ±5 percent. For
torque, the onboard computer would need to convert measured engine
parameters into useful units. The manufacturer would probably need to
monitor a surrogate value such as intake manifold pressure or throttle
position (or both), then rely on a look-up table programmed into the
onboard computer to convert these torque indicators into newton-meters.
Manufacturers may also want to program the look-up tables for torque
conversion into a remote scan tool. Because of the greater uncertainty
in these measurements and calculations, we are proposing that
manufacturers produce their systems to report torque values that are
within 85 and 105 percent of the true value. This broader range allows
appropriately for the uncertainty in the measurement, while providing
an incentive for manufacturers to make the torque reading as accurate
as possible. Under-reporting torque values would over-predict
emissions. These tolerances are taken into account in the selection of
the field-testing standards, as described in Chapter 4 of the Draft
Regulatory Support Document. We request comment on this approach to
measuring in-use emissions and on any alternate approaches.
We request comment on all aspects of field-testing standards and
procedures.

E. Special Compliance Provisions

We are proposing a variety of provisions to address the particular
concerns of small-volume manufacturers of Large SI engines. These
provisions are generally designed to address the limited capital and
engineering resources of companies that produce very few engines.
As described in Section IV.B.4, we are proposing a provision to
allow manufacturers to certify Large SI engines to emission standards
for engines below 19 kW if they have displacement below 1 liter and
rated power between 19 and 30 kW. We are proposing to expand this
flexibility to include a limited number of engines up to 2.5 liters.
This provision would be available for manufacturers producing 300 or
fewer Large SI engines annually nationwide for the 2004 through 2006
model years. We request comment on this arrangement, especially in
three areas. First, we request comment on the possible need to adjust
the 30 kW cap for these engines to ensure that we include the
appropriate engines. Second, we request comment on the sales threshold
and whether a greater allowance would be necessary to accommodate the
sales levels of small-volume manufacturers. Finally, since many of
these engines may be used in places where individual exposure to CO
emissions is a concern, we request comment on adopting an intermediate
CO emission standard for these engines. The CO emission standard for
engines rated below 19 kW is currently about 600 g/kW-hr. Engines with
displacement between 1 and 2.5 liters generally have much lower CO
emissions than small lawn and garden engines. Baseline emission levels
on

[[Page 51134]]

small automotive-type engines shows that uncontrolled emission levels
are about 130 g/kW-hr. We request comment on adopting this as a CO
standard for engines that use the provision described in this
paragraph.
Starting in 2007, we propose to discontinue the provisions
described above for engines between 1 and 2.5 liters. In their place,
we propose to adopt for three model years the standards that would
otherwise apply in 2004 (4 g/kW-hr HC+NO_X and 50 g/kW-hr CO
with steady-state duty cycles). Starting in 2010, there would no longer
be separate emission standards for small-volume manufacturers. Since
upgrading to the anticipated emission-control technology substantially
improves performance, we expect that small-volume manufacturers may
find it advantageous to introduce these technologies ahead of the
schedule described here.
We are proposing several additional provisions to reduce the burden
of complying with emission standards; we propose to apply these
provisions to all manufacturers. These include (1) reduced production-
line testing rates after consistent testing with good emission results,
(2) allowance for alternative, low-cost testing methods to test
production-line engines, (3) a flexible approach to developing
deterioration factors, which gives the manufacturer broad discretion to
develop appropriate emission-durability estimates.
We are also proposing provisions to address hardship circumstances,
as described in Section VII.C. For Large SI engines, we are proposing a
longer available extension of the deadline for meeting emission
standards for small-volume manufacturers. Under this provision, we
would extend the deadline by three years for companies that qualify for
special treatment under the hardship provisions. We would, however, not
extend the deadline for compliance beyond the three-year period. This
approach considers the fact that, unlike most other engine categories,
qualifying small businesses are more likely to be manufacturers
designing their own products. Other types of engines more often involve
importers, which are limited more by available engine suppliers than
design or development schedules.

F. Technological Feasibility of the Standards

Our general goal in designing the proposed standards is to develop
a program with technologically feasible standards that will achieve
significant emission reductions. Our standards must comply with Clean
Air Act section 213(a)(3), as described in Section III.B. The Act also
instructs us to first consider standards equivalent in stringency to
standards for comparable motor vehicles or engines (if any) regulated
under section 202 of the Act, taking into consideration technological
feasibility, costs, and other factors (the relevant engines regulated
under section 202 are automotive and highway truck engines). We are
proposing emission standards that depend on the industrial versions of
established automotive technologies. The most recent advances in
automotive technology have made possible even more dramatic emission
reductions. However, we believe that transferring some of these most
advanced technologies would not be appropriate for nonroad engines at
this time, especially considering the much smaller sales volumes for
amortizing fixed costs and the additional costs associated with the
first-time regulation of these engines. On the other hand, the proposed
emission standards for Large SI align well with standards we have
adopted for the next tier of heavy-duty highway gasoline engines (64 FR
58472, October 29, 1999). We have also adopted long-term standards for
these engines that require significant further reductions with more
sophisticated technologies (66 FR 5002, January 18, 2001).
To comply with the 2004 model year standards, manufacturers should
not need to do any development, testing, or certification work that is
not already necessary to meet California ARB standards in 2004. As
shown in Chapter 4 of the Draft Regulatory Support Document,
manufacturers can meet these standards with three-way catalysts and
closed-loop fuel systems. These technologies have been available for
industrial engine applications for several years. Moreover, several
manufacturers have already completed the testing effort to certify with
California ARB that their engines meet these standards. Complying with
the proposed standards nationwide in 2004 would therefore require
manufacturers only to produce greater numbers of the engines complying
with the California standards.
Chapter 4 of the Draft Regulatory Support Document further
describes data and rationale showing why we believe that the proposed
2007 model year emission standards under the steady-state and transient
duty-cycles and field-testing procedures are feasible. In summary, SwRI
testing and other data show that the same catalyst and fuel-system
technologies needed to meet the 2004 standards can be optimized to meet
more stringent emission standards. Applying further development allows
the design engineer to fine-tune control of air-fuel ratios and address
any high-emission modes of operation to produce engines that
consistently control emissions to very low levels, even considering the
wide range of operation experienced by these engines. The proposed
numerical emission standards are based on measured emission levels from
engines that have operated for at least 5,000 hours with a functioning
emission-control system. These engines demonstrate the achievable level
of control from catalyst-based systems and provide a significant degree
of basic development that should help manufacturers in optimizing their
own engines.
We believe it is appropriate to initiate the second stage of
standards in 2007, because we believe that applying these emission
standards earlier would not allow manufacturers enough stability
between introduction of different phases of emission standards to
amortize their fixed costs and prepare for complying with the full set
of requirements proposed in this notice. Three years of stable emission
standards, plus the remaining lead time before 2004, allows
manufacturers enough time to go through the development and
certification effort to comply with the proposed standards. The
proposed provisions to allow ``family banking'' for early compliance
should provide an additional tool for companies that choose to spread
out their design and certification efforts.
The proposed emission standards would either have no impact or a
positive impact with respect to noise, energy, and safety, as described
in Chapter 4 of the Draft Regulatory Support Document. In particular,
the anticipated fuel savings associated with the expected emission-
control technologies would provide a very big energy benefit related to
new emission standards. The projected technologies are currently
available and are consistent with those anticipated for complying with
the emission standards adopted by California ARB. The lead time for the
proposed interim and final emission standards allows manufacturers
enough time to optimize these designs to most effectively reduce
emissions from the wide range of Large SI equipment applications.

V. Recreational Marine Diesel Engines

This section describes the new provisions proposed for 40 CFR part
94, which would apply to engine manufacturers and other certificate
holders. This section also discusses

[[Page 51135]]

proposed test equipment and procedures for anyone who tests engines to
show they meet emission standards. We are proposing the same general
compliance provisions from 40 CFR part 94 for engine manufacturers,
equipment manufacturers, operators, rebuilders, and others. Similar
general compliance provisions are described for the other engines
included in this proposal in Section VII. See Section III for a
description of our general approach to regulating nonroad engines and
how manufacturers show that they meet emission standards.

A. Overview

We are proposing exhaust and crankcase emission standards for
recreational marine diesel engines with power ratings greater than or
equal to 37 kW. We are proposing emission standards for hydrocarbons
(HC), oxides of nitrogen ( NO_X), carbon monoxide (CO), and
particulate matter (PM) beginning in 2006. We believe manufacturers
will be able to use technology developed for use on land-based nonroad
and commercial marine diesel engines. To encourage the introduction of
low-emission technology, we are also proposing voluntary ``Blue Sky''
standards which are 40 percent lower than the proposed standards. We
also recognize that there are many small businesses that manufacture
recreational marine diesel engines; we are therefore proposing several
regulatory flexibility options for small businesses that should help
minimize any unique burdens caused by emission regulation. A history of
environmental regulation for marine engines is presented in Section I.
We have determined there are at least 16 companies manufacturing
marine diesel engines for recreational vessels. Six of the identified
companies are considered small businesses as defined by the Small
Business Administration (fewer than 1000 employees). Nearly 75 percent
of diesel engines sales for recreational vessels in 2000 can be
attributed to three large companies. Based on sales estimates for 2000,
the six small businesses represent approximately 4 percent of
recreational marine diesel engine sales. The remaining companies each
comprise between two and seven percent of sales for 2000.
Diesel engines are primarily available in inboard marine
configurations, but may also be available in sterndrive and outboard
marine configurations. Inboard diesel engines are the primary choice
for many larger recreational boats.

B. Engines Covered by This Proposal

The standards we are proposing in this section apply to
recreational marine diesel engines. These engines were excluded from
our final standards for commercial marine diesel engines finalized in
1999 because we thought their operation in planing mode might impose
design requirements on recreational boat builders (64 CFR 73300,
December 29, 1999). Commercial marine vessels tend to be displacement-
hull vessels, designed and built for a unique commercial application
(e.g., towing, fishing, general cargo). Power ratings for engines used
on these vessels are analogous to land-based applications, and these
engines are generally warranted for 2,000 to 5,000 hours of use.
Recreational vessels, on the other hand, tend to be planing vessels,
and engines used on these vessels are designed to achieve higher power
output with less engine weight. This increase in power reduces the
lifetime of the engine; recreational marine engines are therefore
warranted for fewer hours of operation than their commercial
counterparts. In our previous rulemaking, recreational engine industry
representatives raised concerns about the ability of these engines to
meet the standards without substantial changes in the size and weight
of the engine. Such changes could have an impact on vessel builders,
who might have to redesign vessel hulls to accommodate the new engines.
Because most recreational vessel hulls are made on fiberglass molds,
this could be a significant burden for recreational vessel builders.
Since we finalized the commercial marine diesel engine standards,
we determined that recreational marine diesel engines can achieve those
same emission standards without significant impacts on engine size and
weight. Section V.G of this document and Chapters 3 and 4 of the Draft
Regulatory Support Document describe the several technological changes
we anticipate manufacturers will use to comply with the new emission
standards. None of these technologies has an inherent negative effect
on the performance or power density of an engine. As with engines in
land-based applications, we expect that manufacturers will be able to
use the range of technologies available to maintain or even improve the
performance capabilities of their engines. We are nevertheless
proposing to establish a separate program for recreational marine
diesel engines in this rule. This will allow us to tailor certain
aspects of the program to these applications, notably the not-to-exceed
requirements. We seek comment on whether this approach is appropriate
or if we should remove the distinction and apply identical emission-
control requirements to both commercial and recreational marine diesel
engines.
To distinguish between commercial and recreational marine diesel
engines for the purpose of emission controls, it is necessary to define
``recreational marine diesel engine.'' According to the definition we
finalized in our commercial marine diesel engine rule, recreational
marine engine means a propulsion marine engine that is intended by the
manufacturer to be installed on a recreational vessel. The engine must
be labeled to distinguish it from a commercial marine diesel engine.
The label must read: ``THIS ENGINE IS CATEGORIZED AS A RECREATIONAL
ENGINE UNDER 40 CFR PART 94. INSTALLATION OF THIS ENGINE IN ANY
NONRECREATIONAL VESSEL IS A VIOLATION OF FEDERAL LAW SUBJECT TO
PENALTY.''
We are also including in the proposed definition that a
recreational marine engine must be a Category 1 marine engine (have a
displacement of less than 5 liters per cylinder). One manufacturer
commented after the ANPRM that only engines less than 2.5 liters per
cylinder in displacement should be considered recreational. We request
comment on this size cut-off and we request comment on allowing
manufacturers flexibility in defining the upper limit of their
recreational product line provided that it is between 2.5 and 5 liters
per cylinder.
For the purpose of the recreational marine diesel engine
definition, recreational vessel was defined as ``a vessel that is
intended by the vessel manufacturer to be operated primarily for
pleasure or leased, rented, or chartered to another for the latter's
pleasure.'' To put some boundaries on that definition, since certain
vessels that are used for pleasure may have operating characteristics
that are more similar to commercial marine vessels (e.g., excursion
vessels and charter craft), we drew on the Coast Guard's definition of
a ``small passenger vessel'' (46 U.S.C 2101(35)) to further delineate
what would be considered to be a recreational vessel. Specifically, the
term ``operated primarily for pleasure or leased, rented or chartered
to another for the latter's pleasure'' would not include the following
vessels: (1) Vessels of less than 100 gross tons that carry more than 6
passengers; (2) vessels of 100 gross tons or more than carry one or
more passengers; or (3) vessels used solely for competition. For the
purposes

[[Page 51136]]

of this definition, a passenger is defined by 46 U.S.C 2101 (21, 21a)
which generally means an individual who pays to be on the vessel.
We received several comments in response to the ANPRM on these
definitions. Engine manufacturers were concerned that the definitions
may be unworkable for engine manufacturers, since they cannot know
whether a particular recreational vessel might carry more than six
passengers at a time. All they can know is whether the engine they
manufacture is intended by them for installation on a vessel designed
for pleasure and having the planing, power density and performance
requirements that go along with that use.
We responded to similar concerns in the Summary and Analysis of
Comments for the commercial marine diesel engine rule, explaining that
a vessel would be considered a recreational vessel if the boat builder
intends that the customer will operate the boat consistent with the
recreational-vessel definition.\132\ Relying on the boat builder's
intent is necessary since manufacturers need to establish a vessel's
classification before it is sold, whereas the Coast Guard definitions
apply at the time of use. The definition therefore relies on the intent
of the boat builder to establish that the vessel will be used
consistent with the above criteria. If a boat builder manufactures a
vessel for a customer who intends to use the vessel for recreational
purposes, we would always consider that a recreational vessel
regardless of how the owner (or a subsequent owner) actually uses it.
---------------------------------------------------------------------------

\132\ Summary and Analysis of Comments: Control of Emissions
from Marine Diesel Engines. EPA420-R-99-028, November 1999, Docket
A-97-50, document V-C-1.
---------------------------------------------------------------------------

We are proposing to retain our existing definition of recreational
marine vessel. We request comment on all aspects of this definition. We
are also requesting comment on how to verify the validity of the vessel
manufacturer's original intent. One option, as noted in the Summary and
Analysis of Comments for the previous rule, would be written assurance
from the buyer.
We are also requesting comment on two alternative approaches for
the definition of recreational marine vessel that were suggested by
ANPRM commenters. The first recommends that we follow the definition in
46 U.S.C. 2101(25), which defines a recreational vessel as one ``being
manufactured or operated primarily for pleasure, or leased, rented, or
chartered to another for the latter's pleasure.''\133\ The second
recommends that we define recreational vessel as one (1) which by
design and construction is intended by the manufacturer to be operated
primarily for pleasure, or to be leased, rented, or chartered to
another for the latter's pleasure; and (2) whose major structural
components are fabricated and assembled in an indoor production-line
manufacturing plant or similar land-side operation and not in a dry
dock, graving dock, or marine railway on the navigable waters of the
United States.\134\ We request comment on whether either of these
definitions is preferable to the existing definition and, more
specifically, on whether either of these alternative definitions would
be sufficient to ensure that recreational marine diesel engines are
installed on vessels that will be used only for recreational purposes.
---------------------------------------------------------------------------

\133\ Statement of the Engine Manufacturers Association, Docket
A-2000-01, Document No. II-D-33.
\134\ Comments of the National Marine Manufacturers Association,
Docket A-2000-01, Document II-D-27.
---------------------------------------------------------------------------

C. Proposed Standards for Marine Diesel Engines

We are proposing technology-forcing emission standards for new
recreational marine diesel engines with rated power greater than or
equal to 37 kW. This section describes the proposed standards and
implementation dates and gives an outline of the technology that can be
used to achieve these levels. We request comment on these standards and
dates. In particular, commenters should address whether the dates
provide sufficient lead time. The technological feasibility discussion
below (Section V.G) describes our technical rationale in more detail.
1. What Are the Proposed Standards and Compliance Dates?
To propose emission standards for recreational marine diesel
engines, we first considered the Tier 2 standards for commercial marine
diesel engines. Recreational marine diesel engines can use all the
technologies projected for Tier 2 and many of these engines already use
this technology. This includes electronic fuel management,
turbocharging, and separate-circuit aftercooling. In fact, because
recreational engines have much shorter design lives than commercial
engines, it is easier to apply raw-water aftercooling to these engines,
which allows manufacturers to enhance performance while reducing
NO_X emissions.
Engine manufacturers will generally increase the fueling rate in
recreational engines, compared to commercial engines, to gain power
from a given engine size. This helps bring a planing vessel onto the
water surface and increases the maximum vessel speed without increasing
the weight of the vessel. This difference in how recreational engines
are designed and used affects emissions.
We are proposing to implement the commercial marine engine
standards for recreational marine diesel engines, allowing two years
beyond the dates that standards apply for the commercial engines. This
would provide engine manufacturers with additional lead time in
adapting technology to their recreational marine diesel engines. The
proposed standards and implementation dates for recreational marine
diesel engines are presented in Table V.C-1. The subcategories refer to
engine displacement in liters per cylinder.

Table V.C-1.--Proposed Recreational CI Marine Emission Standards and Implementation Dates
----------------------------------------------------------------------------------------------------------------
HC+NO_X g/ Implemen-
Subcategory kW-hr PM g/kW-hr CO g/kW-hr tation date
----------------------------------------------------------------------------------------------------------------
power ³ 37 kW..................................... 7.5 0.40 5.0 2007
0.5 £ disp 0.9
0.9 £ disp 1.2................................... 7.2 0.30 5.0 2006
1.2 £ disp 2.5................................... 7.2 0.20 5.0 2006
disp ³ 2.5........................................ 7.2 0.20 5.0 2009
----------------------------------------------------------------------------------------------------------------

[[Page 51137]]

2. Will I Be Able To Average, Bank, or Trade Emissions Credits?
Section III.C.3 gives an overview of the proposed emission-credit
program, which is consistent with what we adopted for Category 1
commercial marine diesel engines. We are proposing that the emission-
credit program be limited to HC+NO_X and PM emissions.
Consistent with our land-based nonroad and commercial marine diesel
engine regulations, we are proposing to disallow simultaneous
generation of HC+NO_X credits and use of PM credits on the
same engine family, and vice versa. This is necessary because of the
inherent trade-off between NO_X and PM emissions in diesel
engines. We request comment on whether an engine should be allowed to
generate credits on one pollutant while using credits on another, and
whether allowing such an additional flexibility would necessitate a
reconsideration of the stringency of the proposed emission limits.
We are proposing the same maximum value of the Family Emission
Limit (FEL) as for commercial marine diesel engines. For engines with a
displacement of less than 1.2 liters/cylinder, the maximum values are
11.5 g/kW-hr HC+NO_X and 1.2 g/kW-hr PM; for larger engines,
the maximum values are 10.5 g/kW-hr HC+NO_X and 0.54 g/kW-hr
PM. These maximum FEL values were based on the comparable land-based
emission-credit program and will ensure that the emissions from any
given family certified under this program not be significantly higher
than the applicable emission standards. We believe these proposed
maximum values will prevent backsliding of emissions above the baseline
levels for any given engine model. Also, we are concerned that the
higher emitting engines could result in emission increases in areas
such as ports that may have a need for PM or NO_X emission
reductions. Balancing this concern is the fact that recreational marine
diesel engines constitute a small fraction of PM and HC+NO_X
emissions in nonattainment areas. Thus, if a few engine families have
higher emissions then our proposed FEL cap, the incremental emissions
in these areas may not be significant. Also, if we do not promulgate
FEL caps for this category, manufacturers will need to offset high
emitting engines with low-emitting engines to meet the average
standard. We are interested in comments on these issues, on the degree
to which FEL caps would hinder manufacturer flexibility and impose
costs, and the environmental impact of FEL caps. We ask commenters to
address whether we should promulgate FEL caps.
As an alternative, we are requesting comment on whether we should
consider using the MARPOL Annex VI NO_X standard as the
appropriate NO_X FEL upper limit. Under this approach we
would continue to use the land-based Tier 1 PM standard as the
recreational marine diesel engine FEL upper limit. As part of this
approach we would have to accommodate the fact that the MARPOL Annex VI
standard is for NO_X only and these proposed standards are
HC+NO_X. We further request comment under this approach as to
how best to deal with this inconsistency.
We are proposing that emission credits generated under this program
have no expiration, with no discounting applied. This is consistent
with the commercial marine credit program and gives manufacturers
greater flexibility in implementing their engine designs. However, if
we were to revisit the standards proposed today at a later date, we
would have to reevaluate this issue in the context of spillover of
credits in the new program.
Consistent with the land-based nonroad diesel rule, we are also
proposing to disallow using credits generated on land-based engines for
demonstrating compliance with marine diesel engines. In addition, we
propose that credits may not be exchanged between recreational and
commercial marine engines. We are concerned that manufacturers
producing land-based and/or commercial marine engines in addition to
recreational marine engines could effectively trade out of the
recreational marine portion of the program, thereby potentially
obtaining a competitive advantage over small companies selling only
recreational marine engines. In addition, there are two differences in
the way that land-based, commercial marine, and recreational marine
credits are calculated that make the credits somewhat incompatible. The
first is that the difference in test duty cycles means there is an
difference in calculated load factors for each of these categories of
engines. The second is that there are significant differences in the
useful lives. EPA seeks comment on the need for these restrictions and
on the degree to which imposing them may create barriers to low-cost
emission reductions.
We are proposing to allow early banking of emission credits once
this rule is finalized. We believe that early banking of emission
credits will allow for a smoother implementation of the recreational
marine standards. These credits are generated relative to the proposed
standards and are undiscounted. We are aware that there are already
some marine diesel engines that meet the proposed standards, and we are
concerned about windfall credits from engines that generate early
credits without any modifications to reduce emissions. We request
comment on whether or not these engines should be able to generate
credits.
We also propose that manufacturers have the option of generating
credits relative to their pre-control emission levels. If manufacturers
choose this option they will have to develop engine family-specific
baseline emission levels. Credits will then be calculated relative to
the manufacturer-generated baseline emission rates, rather than the
standards. To generate the baseline emission rates, a manufacturer must
test three engines from the family for which the baseline is being
generated. The baseline will be the average emissions of the three
engines. Under this option, engines must still meet the proposed
standards to generate credits, but the credits will be calculated
relative to the generated baseline rather than the standards. However,
any credits generated between the level of the standards and the
generated baseline will be discounted 10 percent. This is to account
for the variability of testing in-use engines to establish the family-
specific baseline levels, which may result from differences in hours of
use and maintenance practices. We request comment on all aspects of the
proposed emission-credit program.
One engine manufacturer commented after the ANPRM that all their
recreational engine product lines fall into the per-cylinder
displacement range with the proposed implementation date of 2006. This
manufacturer expressed concern that it would be burdensome to introduce
all their product lines at one time and presented the idea of phasing
in their product lines from 2005 through 2007 instead. An alternative
to early banking or a revised phase-in would be ``family-banking.''
Under the ``family-banking'' concept, we would allow manufacturers to
certify an engine family early. For each year of certifying an engine
family early, the manufacturer would be able to delay certification of
a smaller engine family by one year. This would be based on the actual
sales of the early family and the projected sales volumes of the late
family; this would require no calculation or accounting of emission
credits. We request comment on this approach or any other approach that
would help manufacturers bring the product lines into compliance to the
proposed standards without

[[Page 51138]]

compromising emissions reductions (see Sec. 1048.145 of the proposed
regulations).
3. Is EPA Proposing Voluntary Standards for These Engines?
a. Blue Sky. Section III.B.5 gives an overview of Blue Sky
voluntary standards. We are proposing to target about a 45-percent
reduction beyond the mandatory standards as a qualifying level for Blue
Sky Series engines to match the voluntary standards already adopted for
commercial marine diesel engines (see Table V.C-2). While the Blue Sky
Series emission standards are voluntary, a manufacturer choosing to
certify an engine under this program must comply with all the
requirements proposed for this category of engines, including allowable
maintenance, warranty, useful life, rebuild, and deterioration factor
provisions. This program would become effective immediately once we
finalize this rule. We request comment on the Blue Sky Series approach
as it would apply to recreational marine diesel engines.

Table V.C.-2.--Blue Sky Voluntary Emission Standards for Recreational
Marine Diesel Engines
[g/kW-hr]
------------------------------------------------------------------------
Rated Brake Power (kW) HC+NO_X PM
------------------------------------------------------------------------
power ³ 37 kW.................................. 4.0 0.24
displ.0.9
0.9£displ.1.2.................................. 4.0 0.18
1.2£displ.2.5.................................. 4.0 0.12
2.5£displ...................................... 5.0 0.12
------------------------------------------------------------------------

b. MARPOL Annex VI. The MARPOL Annex VI standards are discussed
above in Section I.F.3 for marine diesel engines rated above 130 kW. We
are not proposing to adopt the MARPOL Annex VI NO_X emission
limits as Clean Air Act standards at this time. However, we encourage
engine manufacturers to make Annex VI-compliant engines available and
boat builders to purchase and install them prior to the implementation
of our proposed standards. If the international standards are ratified
in the U.S., they would go into effect retroactively to all boats built
January 1, 2000 or later. One advantage of using MARPOL-compliant
engines is that if this happens, users will be in compliance with the
standard without having to make any changes to their engines.
To encourage boat manufacturers to purchase MARPOL Annex VI-
compliant engines prior to the date the Annex goes into force for the
United States, we are proposing a voluntary certification program that
will allow engine manufacturers to obtain a Statement of Voluntary
Compliance to the MARPOL Annex VI NO_X limits. This voluntary
approach to the MARPOL Annex VI emission limits depends on the
assumption that manufacturers will produce MARPOL-compliant engines
before the emission limits go into effect internationally. Engine
manufacturers can use this voluntary certification program to obtain a
Statement of Voluntary Compliance to the MARPOL NO_X
limits.\135\
---------------------------------------------------------------------------

\135\ For more information about our voluntary certification
program, see ``guidance for Certifying to MARPOL Annex VI,'' VPCD-
99-02. This letter is available on our website: http://www.epa.gov/
otaq/regs/nonroad/marine/ci/imolettr.pdf.
---------------------------------------------------------------------------

We request comment on whether or not we should apply the MARPOL
Annex VI standards as a first Tier to this proposed regulation. We also
request comment on reasons for whether or not the MARPOL Annex VI
standards should apply to recreational marine at all.
4. What Durability Provisions Apply?
There are several related provisions that would be needed to ensure
that emission control would be maintained throughout the life of the
engine. Section III gives a general overview of durability provisions
associated with emissions certification. This section discusses these
proposed provisions specifically for recreational marine diesel
engines.
a. How long would my engine have to comply? We propose to require
that manufacturers produce engines that comply over the full useful
life of ten years or until the engine accumulates 1,000 operating
hours, whichever occurs first. We would consider the hours requirement
to be a minimum value for useful life, and would require manufacturers
to comply for a longer period in those cases where they design their
engines to be operated longer than 1,000 hours. In making the
determination that engines are designed to last longer than the
proposed hour limit, we would look for evidence that the engines
continue to reliably deliver the necessary power output without an
unacceptable increase in fuel consumption.
b. How would I demonstrate emission durability? We are proposing
the same durability demonstration requirements for recreational marine
diesel engines as already exist for commercial marine diesel engines.
This means that recreational marine engine manufacturers, using good
engineering judgment, would generally need to test one or more engines
for emissions before and after accumulating 1,000 operating hours
(usually performed by continuous engine operation in a laboratory). The
results of these tests are referred to as ``durability data,'' and are
used to determine the rates at which emissions are expected to increase
over the useful life of the engine for each engine family (the rates
are known as deterioration factors). However, in many cases,
manufacturers would be allowed to use durability data from a different
engine family, or for the same engine family in a different model year.
Because of this allowance to use the same data for multiple engine
families, we expect durability testing to be very limited.
We are also proposing the same provisions from the commercial
marine rulemaking for how durability data are to be collected and how
deterioration factors are to be generated. These requirements are in 40
CFR 94.211, 94.218, 94.219, and 94.220. These sections describe when
durability data from one engine family can be used for another family,
how to select to the engine configuration that is to be tested, how to
conduct the service accumulation, and what maintenance can be performed
on the engine during this service accumulation.
c. What maintenance would be allowed during service accumulation?
For engines certified to a 1,000-hour useful life, the only maintenance
that would be allowed is regularly scheduled maintenance unrelated to
emissions that is technologically necessary. This could typically
include changing engine oil, oil filter, fuel filter, and air filter.
We request comment on the allowable maintenance during service
accumulation.
d. Would production-line testing be required? We are proposing to
apply the production-line testing requirements for commercial marine
engines to recreational marine diesel engines, with the additional
provisions described in Section III.C.4. A manufacturer would have to
test one percent of its total projected annual sales of Category 1
engines each year to meet production-line testing requirements. We are
proposing that manufacturers combine recreational and commercial engine
families in calculating their sample sizes for production-line testing.
We are not proposing a minimum number of tests, so a manufacturer could
produce up to 100 marine diesel engines without doing any production-
line testing.
5. Do These Standards Apply to Alternative-Fueled Engines?
These proposed standards apply to all recreational marine diesel
engines,

[[Page 51139]]

without regard to the type of fuel used. While we are not aware of any
alternative-fueled recreational marine engines that are currently being
sold into the U.S. market, we are proposing alternate forms of the
hydrocarbon standards to address the potential for natural gas-fueled
and alcohol-fueled engines. In our regulation of highway vehicles and
engines, we determined it is not appropriate to apply total hydrocarbon
standards to engines fueled with natural gas (which is comprised
primarily of methane), but rather that nonmethane hydrocarbon (NMHC)
standards should be used (59 FR 48472, September 21, 1994). These
alternate forms follow the precedent set in previous rulemakings to
make the standards similar in stringency and environmental impact.
Similarly, we determined that alcohol-fueled highway engines and
vehicles should be subject to HC-equivalent (HCE) standards instead of
HC standards (54 FR 14426, April 11, 1989). HC-equivalent emissions are
calculated from the oxygenated organic components and non-oxygenated
organic components of the exhaust, summed together based on the amount
of organic carbon present in the exhaust. Thus, we are proposing that
alcohol-fueled recreational marine engines comply with total
hydrocarbon equivalent (THCE) plus NO_X standards instead of
THC plus NO_X standards.
6. Is EPA Controlling Crankcase Emissions?
We are proposing to require manufacturers to prevent crankcase
emissions from recreational marine diesel engines, with one exception.
We are proposing to allow turbocharged recreational marine diesel
engines to be built with open crankcases, as long as the crankcase
ventilation system allows measurement of crankcase emissions. For these
engines with open crankcases, we will require crankcase emissions to be
either routed into the exhaust stream to be included in the exhaust
measurement, or to be measured separately and added to the measured
exhaust mass. These measurement requirements would not add
significantly to the cost of testing, especially where the crankcase
vent is simply routed into the exhaust stream prior to the point of
exhaust sampling. This proposal is consistent with our previous
regulation of crankcase emissions from such diverse sources as
commercial marine engines, locomotives, and passenger cars.
7. What Are the Smoke Requirements?
We are not proposing smoke requirements for recreational marine
diesel engines. Marine diesel engine manufacturers have stated that
many of their engines, though currently unregulated, are manufactured
with smoke limiting controls at the request of customers. Users seek
low smoke emissions both because they dislike the exhaust residue on
decks and because they can be subject to penalties in ports with smoke
emission requirements. In many cases, marine engine exhaust gases are
mixed with water prior to being released. This practice reduces smoke
visibility. Moreover, we believe the PM standards proposed here for
diesel engines will have the effect of limiting smoke emissions as
well. We request comment on this position and, specifically, on whether
there is a need at this time for additional control of smoke emissions
from recreational marine diesel engines, and if so, what the
appropriate limits should be.
We also request comment on an appropriate test procedure for
measuring smoke emissions, in case we choose to pursue smoke limits.
There is currently no established test procedure for a marine engine to
measure compliance with a smoke limit. Most propulsion marine engines
operate over a torque curve governed by the propellor. Consequently, a
vessel with an engine operating at a given speed will have a narrow
range of torque levels. Some large propulsion marine engines have
variable-pitch propellers, in which case the engine operates much like
constant-speed engines. Note that the International Organization for
Standardization (ISO) is working on a proposed test procedure for
marine diesel engines.\136\ As this procedure is finalized by ISO and
emission data become available, we may review the issue of smoke
requirements for all marine diesel engines. We request comment on this
overall approach to smoke emissions from marine diesel engines, as well
as comment on the draft ISO procedures.
---------------------------------------------------------------------------

\136\ International Standards Organization, 8178-4,
``Reciprocating internal combustion engines--Exhaust emission
measurement--Part 4: Test cycles for different engine
applications,'' Docket A-2000-01, Document II-A-19.
---------------------------------------------------------------------------

8. What Are the Proposed Not-To-Exceed Standards and Related
Requirements?
We are proposing not-to-exceed requirements similar to those
finalized for commercial marine diesel engines. At the time of
certification, manufacture would have to submit a statement that its
engines will comply with these requirements under all conditions that
may reasonably be expected to occur in normal vessel operation and use.
The manufacturer would provide a detailed description of all testing,
engineering analysis, and other information that forms the basis for
the statement. This certification could be based on testing or on other
research which could be used to support such a statement that is
consistent with good engineering judgment. We request comment on
applying the proposed NTE requirements to recreational marine diesel
engines and on the application of the requirements to these engines.
a. Concept. Our goal is to achieve control of emissions over the
broad range of in-use speed and load combinations that can occur on a
recreational marine diesel engine so that real-world emission control
is achieved, rather than just controlling emissions under certain
laboratory conditions. An important tool for achieving this goal is an
in-use program with an objective standard and an easily implemented
test procedure. Prior to this concept, our approach has been to set a
numerical standard on a specified test procedure and rely on the
additional prohibition of defeat devices to ensure in-use control over
a broad range of operation not included in the test procedure.
We are proposing to apply the defeat device provisions established
for commercial marine engines to recreational marine diesel engines in
addition to the NTE requirements (see 40 CFR 94.2). A design in which
an engine met the standard at the steady-state test points but was
intentionally designed to approach the NTE limit everywhere else would
be considered to be defeating the standard. Electronic controls that
recognize when the engine is being tested for emissions and adjust the
emissions from the engine would be an example of a defeat device,
regardless of the emissions performance of the engine.
No single test procedure can cover all real-world applications,
operations, or conditions. Yet to ensure that emission standards are
providing the intended benefits in use, we must have a reasonable
expectation that emissions under real-world conditions reflect those
measured on the test procedure. The defeat-device prohibition is
designed to ensure that emission controls are employed during real-
world operation, not just under laboratory or test-procedure
conditions. However, the defeat-device prohibition is not a quantified
standard and does not have an associated test procedure, so it does not
have the clear objectivity and ready

[[Page 51140]]

enforceability of a numerical standard and test procedure. As a result,
using a standardized test procedure alone makes it harder to ensure
that engines will operate with the same level of control in the real
world as in the test cell.
Because the ISO E5 duty cycle uses only five modes on an average
propeller curve to characterize marine engine operation, we are
concerned that an engine designed to the duty cycle would not
necessarily perform the same way over the range of speed and load
combinations seen on a boat. These duty cycles are based on average
propeller curves, but a propulsion marine engine may never be fitted
with an ``average propeller.'' For instance, an engine fit to a
specific boat may operate differently based on how heavily the boat is
loaded.
To ensure that emissions are controlled from recreational marine
engines over the full range of speed and load combinations seen on
boats, we propose to establish a zone under the engine's power curve
where the engine may not exceed a specified emission limit. This limit
would apply to all of the regulated pollutants under steady-state
operation. In addition, we propose that the whole range of real ambient
conditions be included in this ``not-to-exceed'' (NTE) zone testing.
The NTE zone, limit, and ambient conditions are described below.
We believe there are significant advantages to taking this
approach. The test procedure is very flexible so it can represent the
majority of in-use engine operation and ambient conditions. Therefore,
the NTE approach takes all of the benefits of a numerical standard and
test procedure and expands it to cover a broad range of conditions.
Also, laboratory testing makes it harder to perform in-use testing
because either the engines would have to be removed from the vessel or
care would have to be taken that laboratory-type conditions can be
achieved on the vessel. With the NTE approach, in-use testing and
compliance become much easier since emissions may be sampled during
normal vessel use. Because this approach is objective, it makes
enforcement easier and provides more certainty to the industry of what
is expected in use versus over a fixed laboratory test procedure.
Even with the NTE requirements, we believe it is still important to
retain standards based on the steady-state duty cycles. This is the
standard that we expect the certified marine engines to meet on average
in use. The NTE testing is more focused on maximum emissions for
segments of operation and should not require additional technology
beyond what is used to meet the proposed standards. We believe basing
the emission standards on a distinct cycle and using the NTE zone to
ensure in-use control creates a comprehensive program. In addition, the
steady-state duty cycles give a basis for calculating credits for
averaging, banking, and trading.
b. Shape of the NTE zone. Figure V-C-1 illustrates our proposed NTE
zone for recreational marine diesel engines. We based this zone on the
range of conditions that these engines could typically see in use.
Also, we propose to divide the zone into subzones of operation which
have different limits as described below. Chapter 4 of the Draft
Regulatory Support Document describes the development of the boundaries
and conditions associated with the proposed NTE zone. We request
comment on the proposed NTE zone.
BILLING CODE 6560-50-P
[GRAPHIC]
[TIFF OMITTED] TP05OC01.000

BILLING CODE 6560-50-C
We propose to allow manufacturers to petition to adjust the size
and shape of the NTE zone for certain engines if they can certify that
the engine will not see operation outside of the revised NTE zone in
use. This way, manufacturers could avoid having to test their engines
under operation that they would never see in use. However,
manufacturers would still be responsible for all operation of an engine
on a vessel that

[[Page 51141]]

would reasonably be expected to be seen in use and would be responsible
for ensuring that their specified operation is indicative of real-world
operation. In addition, if a manufacturer designs an engine for
operation at speeds and loads outside of the proposed NTE zone (i.e.,
variable-speed engines used with variable-pitch propellers), the
manufacturer would be responsible for notifying us so their NTE zone
can be modified appropriately to include this operation.
c. Transient operation. We are proposing that only steady-state
operation be included in the NTE testing. We are basing the test for
determining certification emissions levels on the ISO E5 steady-state
duty cycles. The goal of the NTE, for this proposal, is to cover the
operation away from the five modes on the assumed propeller curve. Our
understanding is that the majority of marine engine operation is
steady-state; however, we recognize that recreational marine use would
likely be more transient than commercial marine use. At this time we do
not have enough data on marine engine operation to accurately determine
the amount of transient operation that occurs. We are aware that the
high-load transient operation seen when a boat comes to plane would not
be included in the NTE zone as defined, even if we would require
compliance with NTE standards during transient operation. We are also
aware that these speed and load points could not be achieved under
steady-state operation for a properly loaded boat in use.
Our proposal to exclude transient operation from NTE testing is
consistent with the commercial marine diesel requirements. Also, the
proposed standards are technology-forcing and are for a previously
unregulated industry. We believe excluding transient operation will
simplify the requirements on this industry while still maintaining
proportional emission reductions due to the technology-forcing nature
of this proposal. We intend to study marine operation to understand
better the effects of transient operation on emissions. If we find that
excluding transient operation from the compliance requirements results
in a significant increase in emissions, we will revisit this provision
in the future. We request comment on the appropriateness of excluding
transient operation from NTE requirements.
d. Emission standards. We are proposing emission standards for an
NTE zone representing a multiplier times the weighted test result used
for certification. Because an emission level is an average of various
points over a test procedure, a multiplier of is inconsistent with the
idea of a Federal Test Procedure standard as an average. This is
consistent with the concept of a weighted modal emission test, such as
the steady-state tests included in this proposal.
Consistent with the requirements for commercial marine engines, we
propose that recreational marine diesel engines must meet a cap of 1.5
times the certified level for HC+NO_X, PM, and CO for the
speed and power subzone below 45 percent of rated power and a cap of
1.2 times the certified levels at or above 45 percent of rated power.
However, we are proposing an additional subzone, when compared to the
commercial NTE zone, at speeds greater than 95 percent of rated. We are
proposing a cap of 1.5 times the certified levels for this subzone.
This additional subzone addresses the typical recreational design for
higher rated power. We understand that this power is needed to ensure
that the engine can bring the boat to plane.
We are aware that marine diesel engines may not be able to meet the
emissions limit under all conditions. Specifically, there are times
when emission control must be compromised for startability or safety.
We are not proposing that engine starting be included in the NTE
testing. In addition, manufacturers would have the option of
petitioning the Administrator to allow emissions to increase under
engine protection strategies such as when an engine overheats. This is
also consistent with the requirements for commercial marine engines.
e. Ambient conditions. Variations in ambient conditions can affect
emissions. Such conditions include air temperature, humidity, and
(especially for aftercooled engines) water temperature. We are
proposing to apply the commercial marine engine ranges for these
variables. Chapter 4 of the Draft Regulatory Support Document provides
more detail on how we determined these ranges. Within the ranges, there
is no calculation to correct measured emissions to standard conditions.
Outside of the ranges, emissions can be corrected back to the nearest
end of the range. The proposed ambient variable ranges are 13 to
35 deg.C (55 to 95 deg.F) for intake air temperature, 7.1 to 10.7 g
water/kg dry air (50 to 75 grains/pound dry air) for intake air
humidity, and 5 to 27 deg.C (41 to 80 deg.F) for ambient water
temperature.

D. Proposed Testing Requirements

40 CFR part 94 details specifications for test equipment and
procedures that apply generally to commercial marine engines. We
propose to base the recreational marine diesel engine test procedures
on this part. Section VIII gives a general discussion of the proposed
testing requirements; this section describes procedures that are
specific to recreational marine such as the duty cycle for operating
engines for emission measurements. Chapter 4 of the Draft Technical
Support Document describes these duty cycles in greater detail.
1. Which Duty Cycles Are Used To Measure Emissions?
For recreational marine diesel engines, we are proposing to use the
ISO E5 duty cycle. This is a 5-mode steady state cycle, including an
idle mode and four modes lying on a cubic propeller curve. ISO intends
for this cycle to be used for all engines in boats less than 24 meters
in length. We propose to apply it to all recreational marine diesel
engines to avoid the complexity of tying emission standards to boat
characteristics. A given engine may be used in boats longer and shorter
than 24 meters; engine manufacturers generally will not know the size
of the boat into which an engine will be installed. Also, we expect
that most recreational boats will be under 24 meters in length. Chapter
4 of the Draft Regulatory Support Document provides further detail on
the ISO E5 duty cycle. We request comment on the appropriateness of
this duty cycle.
2. What Fuels Will Be Used During Emission Testing?
We are proposing to use the same specifications for recreational
marine diesel engines as we have used previously for commercial marine
diesel engines. That means that the recreational engines will use the
same test fuel that is required for testing Category 1 commercial
marine diesel engines, which is a standard nonroad test fuel with
moderate sulfur content. We are not aware of any difference in fuel
specifications for recreational and commercial marine engines of
comparable size.
3. How Would In-Use Testing Be Performed?
We have the authority to perform in-use testing on marine engines
to ensure compliance in use. This testing may include taking in-use
marine engines out of the vessel and testing them in a laboratory, as
well as field testing of in use engines on the boat, in a marine
environment. We request comments on the proposed in-use testing
provisions described below.
We propose to use field-testing data in two ways. First, we would
use it as a

[[Page 51142]]

screening tool, with follow-up laboratory testing over the ISO E5 duty
cycle where appropriate. Second, we would use the data directly as a
basis for compliance determinations provided that field testing
equipment and procedures are capable of providing reliable information
from which conclusions can be drawn regarding what emission levels
would be in laboratory-based measurements.
For marine engines that expel exhaust gases underwater or mix their
exhaust with water, we propose to require manufacturers to equip
engines with an exhaust sample port where a probe can be inserted for
in-use exhaust emission testing. It is important that the location of
this port allow a well-mixed and representative sample of the exhaust.
The purpose of this proposed provision is to simplify in-use testing.
One of the advantages of the not-to-exceed requirements will be to
facilitate in-use testing. This will allow us to perform compliance
testing in the field. As long as the engine is operating under steady-
state conditions in the NTE zone, we will be able to measure emissions
and compare them to the NTE limits.

E. Special Compliance Provisions

The provisions discussed here are designed to minimize regulatory
burdens on manufacturers needing added flexibility to comply with the
proposed engine standards. These manufacturers include engine dressers,
small-volume engine marinizers, and small-volume boat builders.
1. What Are the Proposed Burden Reduction Approaches for Engine
Dressers?
Many recreational marine diesel engine manufacturers take a new,
land-based engine and modify it for installation on a marine vessel.
Some of the companies that modify an engine for installation on a boat
make no changes that would affect emissions. Instead, the modifications
may consist of adding mounting hardware and a generator or reduction
gears for propulsion. It can also involve installing a new marine
cooling system that meets original manufacturer specifications and
duplicates the cooling characteristics of the land-based engine, but
with a different cooling medium (i.e., water). In many ways, these
manufacturers are similar to nonroad equipment manufacturers that
purchase certified land-based nonroad engines to make auxiliary
engines. This simplified approach of producing an engine can more
accurately be described as dressing an engine for a particular
application. Because the modified land-based engines are subsequently
used on a marine vessel, however, these modified engines will be
considered marine diesel engines, which then fall under these proposed
requirements.
To clarify the responsibilities of engine dressers under this rule,
we propose to exempt them from the requirement to certify engines to
the proposed emission standards, as long as they meet the following
seven proposed conditions.
(1) The engine being dressed (the ``base'' engine) must be a
highway, land-based nonroad, or locomotive engine, certified pursuant
to 40 CFR part 86, 89, or 92, respectively, or a marine diesel engine
certified pursuant to this part.
(2) The base engine's emissions, for all pollutants, must be at
least as good as the otherwise applicable recreational marine emission
limits. In other words, starting in 2005, a dressed nonroad Tier 1
engine will not qualify for this exemption, because the more stringent
standards for recreational marine diesel engines go into effect at that
time.
(3) The dressing process must not involve any modifications that
can change engine emissions. We would not consider changes to the fuel
system to be engine dressing because this equipment is integral to the
combustion characteristics of an engine.
(4) All components added to the engine, including cooling systems,
must comply with the specifications provided by the engine
manufacturer.
(5) The original emissions-related label must remain clearly
visible on the engine.
(6) The engine dresser must notify purchasers that the marine
engine is a dressed highway, nonroad, or locomotive engine and is
exempt from the requirements of 40 CFR part 94.
(7) The engine dresser must report annually to us the models that
are exempt pursuant to this provision and such other information as we
deem necessary to ensure appropriate use of the exemption.
We propose that any engine dresser not meeting all these conditions
be considered an engine manufacturer and would accordingly need to
certify that new engines comply with this rule's provisions.
Under this proposal, an engine dresser violating the above criteria
might be liable under anti-tampering provisions for any change made to
the land-based engine that affects emissions. The dresser might also be
subject to a compliance action for selling new marine engines that are
not certified to the required emission standards.
2. What Was the Small Business Advocacy Review Panel?
As described in Section XI.B, the August 1999 report of the Small
Business Advocacy Review Panel addresses the concerns of sterndrive and
inboard engine marinizers, compression-ignition recreational marine
engine marinizers, and boat builders that use these engines.
To identify representatives of small businesses for this process,
we used the definitions provided by the Small Business Administration
for engine manufacturers and boat builders. We then contacted companies
manufacturing internal-combustion engines employing fewer than 1,000
people to be small-entity representatives for the Panel. Companies
selling or installing such engines in boats and employing fewer than
500 people were also considered small businesses for the Panel. Based
on this information, we asked 16 small businesses to serve as small-
entity representatives. These companies represented a cross-section of
both gasoline and diesel engine marinizers, as well as boat builders.
With input from small-entity representatives, the Panel drafted a
report with findings and recommendations on how to reduce the potential
small-business burden resulting from this proposed rule. The Panel's
recommended flexibility options are described in the following
sections.
3. What Are the Proposed Burden Reduction Approaches for Small-Volume
Engine Marinizers?
We are proposing several flexibility options for small-volume
engine marinizers. The purpose of these options is to reduce the burden
on companies for which fixed costs cannot be distributed over a large
number of engines. For this reason, we propose to define a small-volume
engine manufacturer based on annual U.S. sales of engines. This
production count would include all engines (automotive, other nonroad,
etc.) and not just recreational marine engines. We propose to consider
small businesses to be those that produce fewer than 1000 internal
combustion engines per year. Based on our characterization of the
industry, there is a natural break in production volumes above 500
engine sales where the next smallest manufacturers make tens of
thousands of engines. We chose 1000 engines as a limit because it
groups together all the marinizers most needing the proposed burden
reduction approaches, while still allowing for reasonable sales growth.

[[Page 51143]]

The proposed flexibility options for small-volume marinizers are
discussed below and would be used at the manufacturers' discretion. We
request comment on the appropriateness of these flexibility options or
other options.
a. Broaden engine families. We propose to allow small-volume
marinizers to put all of their models into one engine family (or more
as necessary) for certification purposes. Marinizers would then certify
using the ``worst-case'' configuration. This approach is consistent
with the flexibility offered to post-manufacture marinizers under the
commercial marine regulations. The advantage of this approach is that
it minimizes certification testing because the marinizer can certify a
single engine in the first year to represent their whole product line.
As for large companies, the small-volume manufacturers would then be
able carry-over data from year to year until engine design changes
occur that would significantly affect emissions.
We understand that this flexibility alone may not be able to reduce
the burden enough for all small-volume manufactures because it would
still require a certification test. We consider this to be the foremost
cost concern for some small-volume manufacturers, because the test
costs are spread over low sales volumes. Also, we recognize that it may
be difficult to determine the worst-case emitter without additional
testing.
b. Minimize compliance requirements. We propose to waive
production-line and deterioration testing for small-volume marinizers.
We would assign a deterioration factor for use in calculating end-of-
life emission factors for certification. The advantages of this
approach would be to minimize compliance testing. Production-line and
deterioration testing would be more extensive than a single
certification test.
There are also some disadvantages of this approach, because there
would be no testing assurance of engine emissions at the production
line. This is especially a concern without a manufacturer-run in-use
testing program. Also, assigned deterioration factors would not be as
accurate as deterioration factors determined by the manufacturer
through testing. We request comment on appropriate deterioration
factors for the technology discussed in this proposal.
c. Expand engine dresser flexibility. We propose to expand the
engine dresser definition for small-volume marinizers to include water-
cooled turbochargers where the goal is to match the performance of the
non water-cooled turbocharger on the original certified configuration.
We believe this would provide more opportunities for diesel marinizers
to be excluded from certification testing if they operate as dressers.
There would be some potential for adverse emissions impacts because
emissions are sensitive to turbo-matching; however, if the goal of the
marinizer is to match the performance of the original turbocharger,
this risk should be small. We recognize that this option would not
likely benefit all diesel marinizers because changes to fuel management
for power would not qualify under engine dressing.
d. Streamlined certification. We are requesting comment on allowing
small-volume marinizers to certify to a performance standard by showing
their engines meet design criteria rather than by certification
testing. The goal would be to reduce the costs of certification
testing. We are concerned that this approach must be implemented
carefully to work effectively. This would put us in the undesirable
position of specifying engine designs for marinizers, which we have
historically avoided by setting performance standards.
We are not clear on how to set meaningful design criteria for
marine diesel engines. We expect that emission reductions in diesel
engines will be achieved through careful calibration of the engine fuel
and air management systems using strategies such as timing retard and
charge-air cooling. It may not be feasible to specify criteria for
ignition timing, charge-air temperatures, and injection pressures that
would ensure that every engine can achieve the targeted level of
emission control. While we do not believe design criteria can be set to
provide sufficient assurance of emission control from these engines, we
ask for comment on any possible approaches.
We propose to allow small-volume marinizers to certify to the
proposed not-to-exceed (NTE) requirements with a streamlined approach.
We believe small-volume marinizers could make a satisfactory showing
that they meet NTE standards with limited test data. Once these
manufacturers test engines over the proposed five-mode certification
duty cycle (E5), they could use those or other test points to
extrapolate the results to the rest of the NTE zone. For example, an
engineering analysis could consider engine timing and fueling rate to
determine how much the engine's emissions may change at points not
included in the E5 cycle. For this streamlined NTE approach, we propose
that keeping all four test modes of the E5 cycle within the NTE
standards would be enough for small-volume marinizers to certify
compliance with NTE requirements, as long as there are no significant
changes in timing or fueling rate between modes. We request comment on
this approach.
e. Delay standards for five years. We propose that small-volume
marinizers not have to comply with the standards for five years after
they take effect for larger companies. Under this plan the proposed
standards would take effect from 2011 to 2014 for small-volume
marinizers, depending on engine size. We propose that marinizers would
be able to apply this delay to all or just a portion of their
production. They could therefore still sell engines that meet the
standards when possible on some product lines while delaying
introduction of emission-control technology on other product lines.
This option provides more time for small marinizers to redesign their
products, allowing time to learn from the technology development of the
rest of the industry.
While we are concerned about the loss of emission control from part
of the fleet during this time, we recognize the special needs of small-
volume marinizers and believe the added time may be necessary for these
companies to comply with the proposed emission standards. This
additional time will allow small-volume marinizers to obtain and
implement proven, cost-effective emission-control technology. Some
small-volume marinizers have expressed concern to the Small Business
Advocacy Panel that large manufacturers could have competitive
advantage if they market their engines as cleaner than the small-
business engines. Other small-volume manufacturers commented that this
provision would be useful to them.
We are also requesting comment on limited exemptions for small-
volume marinizers. Under this sort of flexibility, upon request from a
small-volume marinizer, we would exempt a small number of engines per
year for 8 to 10 years. An example of a small-volume exemptions would
be 50 marine diesel engines per year. We are concerned, however, that
this approach may not be appropriate given our goal of reducing burden
on small businesses without significant loss in emission control.
f. Hardship provisions. We are proposing two hardship provisions
for small-volume marinizers. Marinizers would be able to apply for this
relief on an annual basis. First, we propose that small marinizers
could petition us for additional time to comply with the standards. The
marinizer would have to make the case that it has taken all

[[Page 51144]]

possible steps to comply but the burden of compliance costs would have
a major impact on the company's solvency. Also, if a certified base
engine were available, we propose that the marinizer would have to use
this engine. We believe this provision would protect small-volume
marinizers from undue hardship due to certification burden. Also, some
emission reduction could be gained if a certified base engine becomes
available.
Second, we propose that small-volume marinizers could also apply
for hardship relief if circumstances outside their control caused the
failure to comply (such as a supply contract broken by parts supplier)
and if failure to sell the subject engines would have a major impact on
the company's solvency. We would consider this relief mechanism as a
option to be used only as a last resort. We believe this provision
would protect small-volume marinizers from circumstances outside their
control.
g. Use of emission credits. We request comment on the
appropriateness of allowing small-volume manufacturers to purchase
credits under the streamlined certification approach described above.
Under this approach, the engine's emission performance for purposes of
certification is determined on the basis of design features rather than
emission test results alone. Certification would therefore depend on
engineering analysis and design criteria. Without a full set of
emission test data, however, it would not be possible for these
manufacturers to participate in an emission-credit program.
We believe the level of credits necessary to offset emissions from
uncontrolled engines could be established conservatively to maximize
assurance of compliance. For this reason, the baseline emissions of the
uncontrolled engine could be based on the worst-case baseline data we
are aware of, which would currently be 20 g/kW-hr HC+NO_X and
1 g/kW-hr PM. The credits needed would then be calculated using the
proposed standards and the usage assumptions presented in Chapter 6 of
the Draft Regulatory Support Document.
Under this limited emission-credit program, we propose that the
participating manufacturer would be able to buy credits offered for
sale by recreational marine diesel engine manufacturers certifying only
on the basis of emission tests (not using the streamlined certification
described above). We propose that cross-trading outside of recreational
marine not be allowed, because it could prevent emission reductions
from being achieved in areas where boats contribute most significantly
to local air pollution and it could prevent new technology from being
applied to recreational marine engines. However, we request comment on
whether or not small-volume marinizers should be able to use credits
generated from other sectors such as land-based nonroad engines.
4. What Are the Proposed Burden Reduction Approaches for Small-Volume
Boat Builders Using Recreational Marine Diesel Engines?
The SBAR Panel Report recommends that we propose burden reduction
approaches for small-volume boat builders. This recommendation was
based on the concern that, although boat builders would not be directly
regulated under the proposed engine standards, they may need to
redesign engine compartments on some boats if engine designs were to
change significantly. Based on comments from industry, we believe these
flexibility options may be appropriate; however, they may also turn out
to be unnecessary.
We are proposing four flexibility options for small-volume vessel
manufacturers using recreational marine diesel engines. The purpose of
these options is to reduce the burden on companies for which fixed
costs cannot be distributed over a large number of vessels. For this
reason, we propose to define a small-volume boat builder as one that
produces fewer than 100 boats for sale in the U.S. in one year and
meets the Small Business Administration definition of a small business
(fewer than 500 employees). The production count would include all
engine-powered recreational boats. We propose that these flexibility
options be used at the manufacturer's discretion. The proposed
flexibility options for small-volume boat builders are discussed below.
We request comment on the appropriateness of these or other flexibility
options.
a. Percent-of-production delay. This proposed flexibility would
allow manufacturers, with written request from a small-volume boat
builder and prior approval from us, to produce a limited number of
uncertified recreational marine engines. We propose that, over a period
of five years (2006-2010), small-volume boat builders would be able to
purchase uncertified engines to sell in boats for an amount equal to 80
percent of engine sales for one year. For example, if the small boat
builder sells 100 engines per year, a total of 80 uncertified engines
may be sold over the five-year period. This should give small boat
builders flexibility to delay using new engine designs for a portion of
business.
We currently believe this flexibility is appropriate, however, it
is possible that this flexibility could turn out to be unnecessary if
the standards do not result in significant changes in engine size,
power-to-weight ratio, or other parameters that would affect boat
design. Moreover, custom boat builders may not need this flexibility if
they design each boat from the ground up. We are also concerned that
this flexibility could reduce the market for the certified engines
produced by the engine manufacturers and could make it difficult for
customs inspectors to know which uncertified engines can be imported.
We therefore propose that engines produced under this flexibility would
have to be labeled as such.
b. Small-volume allowance. This proposed flexibility is similar to
the percent-of-production allowance, but is designed for boat builders
with very small production volumes. The only difference with the above
flexibility would be that the 80-percent allowance described above
could be exceeded as long as sales do not exceed either 10 engines per
year or 20 engines over five years (2006-2010). This proposed
flexibility would apply only to engines less than or equal to 2.5
liters per cylinder.
c. Existing inventory and replacement engine allowance. We propose
that small-volume boat builders be allowed to sell their existing
inventory after the implementation date of the new standards. However,
no purposeful stockpiling of uncertified engines would be permitted.
This provision is intended to allow small boat builders flexibility to
turn over engine designs.
d. Hardship relief provision. We propose that small boat builders
could apply for hardship relief if circumstances outside their control
caused the problem (for example, if a supply contract were broken by
the engine supplier) and if failure to sell the subject vessels would
have a major impact on the company's solvency. This relief would allow
the boat builder to use an uncertified engine and would be considered a
mechanism of last resort. These hardship provisions are consistent with
those currently in place for post-manufacture marinizers of commercial
marine diesel engines.

F. Technical Amendments

The proposed regulations include a variety of amendments to the
programs already adopted for marine spark-ignition and diesel engines,
as described in the following paragraphs.

[[Page 51145]]

1. 40 CFR Part 91
We have identified three principal amendments to the requirements
for outboard and personal watercraft engines. First, we are proposing
to add a definition of United States. This is especially helpful in
clearing up questions related to U.S. territories in the Carribean Sea
and the Pacific Ocean. Second, we have found two typographical errors
in the equations needed for calculating emission levels in 40 CFR
91.419. Finally, we are proposing to clarify testing rates for the in-
use testing program. The regulations currently specify a maximum rate
of 25 percent of a manufacturer's engine families. We are proposing to
clarify that for manufacturers with fewer than four engine families,
the maximum testing rate should be one family per year in place of the
percentage calculation. We request comment on these amendments.
Specifically, we request comment on whether there is a need to delay
the effectiveness of any of these amendments to allow manufacturers
time to comply with new requirements.
2. 40 CFR Part 94
We are proposing several regulatory amendments to the program for
commercial marine diesel engines. Several of these are straightforward
edits for correct grammar and cross references.
We propose to change the definition of United States, as described
in the previous section.
We are proposing to add a definition for spark-ignition, consistent
with the existing definition for compression-ignition. This would allow
us to define compression-ignition as any engine that is not spark-
ignition. This would help ensure that marine emission standards for the
different types of engines fit together appropriately. We do not expect
this change to affect any current engines.
The discussion of production-line testing in Section III includes a
proposal to reduce testing rates after two years of consistent good
performance. We propose to extend this provision to commercial marine
diesel engines as well.
The test procedures for Category 2 marine engines give a cross-
reference to 40 CFR part 92, which defines the procedures for testing
locomotives and locomotive engines. Part 92 specifies a wide range of
ambient temperatures for testing, to allow for outdoor measurements. We
expect all testing of Category 2 marine engines to occur indoors and
are therefore proposing to adopt a range of 13 deg. to 30 deg. C
(55 deg. to 86 deg. F) for emission testing.
We request comment on modifying the language prohibiting emission
controls that increase unregulated pollutants. The existing language
states:

An engine with an emission-control system may not emit any
noxious or toxic substance which would not be emitted in the
operation of the engine in the absence of such a system, except as
specifically permitted by regulation.

Amended regulatory language would focus on preventing emissions that
would endanger public welfare, rather than setting a standard that
allows no tradeoff between pollutants. We are considering this also in
emission-control programs for other types of engines, since various
prospective engine technologies require more careful consideration of
this issue.

You may not design your engines with emission-control devices,
systems, or elements of design that cause or contribute to an
unreasonable risk to public health, welfare, or safety while
operating. This applies especially if the engine emits any noxious
or toxic substance it would otherwise not emit.

After completing the final rule for commercial marine diesel
engines, manufacturers expressed a concern about the phase-in schedule
for engine models under 2.5 liters per cylinder. Some of these engine
models include ratings above 560 kW (750 hp). When we proposed emission
standards for these engines, we suggested that the larger engines could
certify according to an earlier schedule, since the lower-power engines
from those product lines would need to meet emission standards for
marine and land-based nonroad engines earlier. We received no comment
on this position. We request comment on the need to accommodate
manufacturers' calibration, certification, and production schedules in
aligning the marine and land-based nonroad diesel engine emission
standards and on what offsets are appropriate.

G. Technological Feasibility

We believe the emission-reduction strategies expected for land-
based nonroad diesel engines and commercial marine diesel engines can
also be applied to recreational marine diesel engines. Marine diesel
engines are generally derivatives of land-based nonroad and highway
diesel engines. Marine engine manufacturers and marinizers make
modifications to the engine to make it ready for use in a vessel. These
modifications can range from basic engine mounting and cooling changes
to a restructuring of the power assembly and fuel management system.
Chapters 3 and 4 of the Draft Regulatory Support Document discuss this
process in more detail. Also, we have collected emission data
demonstrating the feasibility of the not-to-exceed requirements. These
data are presented in Chapter 4 of the Draft Regulatory Support
Document.
1. Implementation Schedule
For recreational marine diesel engines, the proposed implementation
schedule allows an additional two years of delay beyond the commercial
marine diesel standards. This represents up to a five-year delay in
standards relative to the implementation dates of the land-based
nonroad standards. This should reduce the burden of complying with the
proposed regulatory scheme by allowing time for carryover of technology
from land-based nonroad and commercial marine diesel engines. In
addition, the proposed implementation dates represent four or more
years of lead time beyond the planned date for our final rule.
2. Standard Levels
Marine diesel engines are typically derived from or use the same
technology as land-based nonroad and commercial marine diesel engines
and should therefore be able to effectively use the same emission-
control strategies. In fact, recreational marine engines can make more
use of the water they operate in as a cooling medium compared with
commercial marine, because they are able to make use of raw-water
aftercooling. This can help them reduce charge-air intake temperatures
more easily than the commercial models and much more easily than land-
based nonroad diesel engines. Cooling the intake charge reduces the
formation of NO_X emissions.
3. Technological Approaches
We anticipate that manufacturers will meet the proposed standards
for recreational marine diesel engines primarily with technology that
will be applied to land-based nonroad and commercial marine diesel
engines. Much of this technology has already been established in
highway applications and is being used in limited land-based nonroad
and marine applications. Our analysis of this technology is described
in detail in Chapters 3 and 4 of the Draft Regulatory Support Document
for this proposed rule and is summarized here. We request comment on
the applicability of the technology discussed below for CI recreational
marine engines.
Our cost analysis is based on the technology package which we
believe

[[Page 51146]]

most manufacturers will apply and is described in Chapter 5 of the
Draft Regulatory Support Document. Our estimated costs of control are
an ``average'' based on this technology package. This assumes that
reductions from the package are all necessary and that the performance
in the area of emission reductions is linear. While we believe this is
a reasonable approach for estimating the overall costs of compliance,
we are also seeking comment on whether there are different technologies
or different application of the technologies in our package which could
affect the marginal costs of compliance. That is to say, is there an
incremental difference in technology which would reduce (or increase)
costs significantly, and thus significantly affect the costs of control
for a small given margin of additional emission reduction.
By proposing standards that don't go into place until 2006, we are
providing engine manufacturers with substantial lead time for
developing, testing, and implementing emission-control technologies.
This lead time and the coordination of standards with those for land-
based nonroad engines allows time for a comprehensive program to
integrate the most effective emission-control approaches into the
manufacturers' overall design goals related to durability, reliability,
and fuel consumption.
Engine manufacturers have already shown some initiative in
producing limited numbers of low-NO_X marine diesel engines.
More than 80 of these engines have been placed into service in
California through demonstration programs. The Draft Regulatory Support
Document further discusses these engines and their emission results.
Through the demonstration programs, we were able to gain some insight
into what technologies can be used to meet the proposed emission
standards.
Highway engines have been the leaders in developing new emission-
control technology for diesel engines. Because of the similar engine
designs in land-based nonroad and marine diesel engines, it is clear
that much of the technological development that has led to lower-
emitting highway engines can be transferred or adapted for use on land-
based nonroad and marine engines. Much of the improvement in emissions
from these engines comes from ``internal'' engine changes such as
variation in fuel-injection variables (injection timing, injection
pressure, spray pattern, rate shaping), modified piston bowl geometry
for better air-fuel mixing, and improvements intended to reduce oil
consumption. Introduction and ongoing improvement of electronic
controls have played a vital role in facilitating many of these
improvements.
Turbocharging is widely used now in marine applications, especially
in larger engines, because it improves power and efficiency by
compressing the intake air. Turbocharging may also be used to decrease
particulate emissions in the exhaust. Today, marine engine
manufacturers generally have to rematch the turbocharger to the engine
characteristics of the marine version of a nonroad engine and often
will add water jacketing around the turbocharger housing to keep
surface temperatures low. Once the nonroad Tier 2 engines are available
to the marine industry, matching the turbochargers for the engines will
be an important step in achieving low emissions.
Aftercooling is a well established technology for reducing
NO_X by decreasing the temperature of the charge air after it
has been heated during compression. Decreasing the charge-air
temperature directly reduces the peak cylinder temperature during
combustion, which is the primary cause of NO_X formation.
Air-to-water and water-to-water aftercoolers are well established for
land-based applications. For engines in marine vessels, there are two
different types of aftercooling: jacket-water and raw-water
aftercooling. With jacket-water aftercooling, the fluid that extracts
heat from the aftercooler is itself cooled by ambient water. This
cooling circuit may either be the same circuit used to cool the engine
or it may be a separate circuit. By moving to a separate circuit,
marine engine manufacturers would be able to achieve further reductions
in the charge-air temperature. This separate circuit could result in
even lower temperatures by using raw water as the coolant. This means
that ambient water is pumped directly to the aftercooler. Raw-water
aftercooling is currently widely used in recreational applications.
Because of the access that marine engines have to a large ambient water
cooling medium, we anticipate that marine diesel engine manufacturers
will largely achieve the reductions in NO_X emissions for
this proposal through the use of aftercooling.
Electronic controls also offer great potential for improved control
of engine parameters for better performance and lower emissions. Unit
pumps or injectors would allow higher-pressure fuel injection with rate
shaping to carefully time the delivery of the whole volume of injected
fuel into the cylinder. Marine engine manufacturers should be able to
take advantage of modifications to the routing of the intake air and
the shape of the combustion chamber of nonroad engines for improved
mixing of the fuel-air charge. Separate-circuit aftercooling (both
jacket-water and raw-water) will likely gain widespread use in
turbocharged engines to increase performance and lower NO_X.
4. Our Conclusions
The proposed standards for recreational marine diesel engines
reasonably reflect what manufacturers can achieve through the
application of available technology. Recreational marine diesel engine
manufacturers will need to use the available lead time to develop the
necessary emission-control strategies, including transfer of technology
from land-based nonroad and commercial marine CI engines. This
development effort will require not only achieving the targeted
emission levels, but also ensuring that each engine will meet all
performance and emission requirements over its useful life. The
proposed standards clearly represent significant reductions compared
with baseline emission levels.
Emission-control technology for diesel engines is in a period of
rapid development in response to the range of emission standards in
place (and under consideration) for highway and land-based nonroad
engines in the years ahead. This development effort will automatically
transfer to some extent to marine engines, because marine engines are
often derivatives of highway and land-based nonroad engines.
Regardless, this development effort would need to expand to meet the
proposed standards. Because the technology development for highway and
land-based nonroad engines will largely constitute basic research of
diesel engine combustion, the results should generally find direct
application to marine engines.
Based on information currently available, we believe it is feasible
for recreational marine diesel engine manufacturers to meet the
proposed standards using combinations of technological approaches
discussed above and in Chapters 3 and 4 of the Draft Regulatory Support
Document. To the extent that the technologies described above may not
yield the full degree of emission reduction anticipated, manufacturers
could still rely on a modest degree of fuel-injection timing retard as
a strategy for complying with the proposed emission standards.
In addition, we believe the flexibilities incorporated into this
proposal will permit marinizers and boat builders to respond to engine
changes in an orderly way. We expect that meeting these requirements
will

[[Continued on page 51147]]

Notices For
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2003
2002
2001
2000
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1996
1995
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Control of Emissions From Nonroad Large Spark Ignition Engines and Recreational Engines (Marine and Land-Based)

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