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

[Federal Register: November 8, 2002 (Volume 67, Number 217)]
[Rules and Regulations]
[Page 68241-68447]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08no02-12]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 89, 90, 91, 94, 1048, 1051, 1065, and 1068
[AMS-FRL-7380-2]
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: Final rule.

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SUMMARY: In this action, we are adopting emission standards for several
groups of nonroad engines that have not been subject to EPA emission
standards. These engines are large spark-ignition engines such as those
used in forklifts and airport ground-service equipment; recreational
vehicles using spark-ignition engines such as off-highway motorcycles,
all-terrain vehicles, and snowmobiles; and recreational marine diesel
engines. Nationwide, these engines and vehicles cause or contribute to
ozone, carbon-monoxide, and particulate-matter nonattainment, as well
as other types of pollution impacting human health and welfare.
We expect that manufacturers will be able to maintain or even
improve the performance of their products when producing engines and
equipment meeting the new standards. Many engines will substantially
reduce their fuel consumption, partially or completely offsetting any
costs associated with the emission standards. Overall, the gasoline-
equivalent fuel savings associated with the anticipated changes in
technology resulting from this rule are estimated to be about 800
million gallons per year once the program is fully phased in. Health
and environmental benefits from the controls included in today's rule
are estimated to be approximately $8 billion per year once the controls
are fully phased in. There are also several provisions to address the
unique limitations of small-volume manufacturers.

DATES: This final rule is effective January 7, 2003.
The incorporation by reference of certain publications listed in
this regulation is approved by the Director of the Federal Register as
of January 7, 2003.

ADDRESSES: Materials relevant to this rulemaking are contained in
Public Docket Numbers A-98-01 and A-2000-01 at the following address:
EPA Docket Center (EPA/DC), Public Reading Room, Room B102, EPA West
Building, 1301 Constitution Avenue, NW., Washington DC. The EPA Docket
Center Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday
through Friday, except on government holidays. You can reach the
Reading Room by telephone at (202) 566-1742, and by facsimile at (202)
566-1741. The telephone number for the Air Docket is (202) 566-1742.
You may be charged a reasonable fee for photocopying docket materials,
as provided in 40 CFR part 2.
For further information on electronic availability of this action,
see SUPPLEMENTARY INFORMATION below.

FOR FURTHER INFORMATION CONTACT: U.S. EPA, Office of Transportation and
Air Quality, Assessment and Standards Division hotline, (734) 214-4636,
asdinfo@epa.gov; Alan Staut, (734) 214-4805.

SUPPLEMENTARY INFORMATION:

Regulated Entities

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

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NAICS Codes Examples of potentially regulated
Category a SIC Codes b entities
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Industry................................... 333618 3519 Manufacturers of new nonroad spark-
ignition engines, new marine engines.
Industry................................... 333111 3523 Manufacturers of farm equipment.
Industry................................... 333112 3531 Manufacturers of construction
equipment, recreational marine
vessels.
Industry................................... 333924 3537 Manufacturers of industrial trucks.
Industry................................... 811310 7699 Engine repair and maintenance.
Industry................................... 336991 ............ Motorcycle manufacturers.
Industry................................... 336999 ............ Snowmobiles and all-terrain vehicle
manufacturers.
Industry................................... 421110 ............ Independent Commercial Importers of
Vehicles and Parts.
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\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 this action regulates particular activities, you
should carefully examine the regulations. You may direct questions
regarding the applicability of this action to the person listed in FOR
FURTHER INFORMATION CONTACT.

Obtaining Electronic Copies of the Regulatory Documents

The preamble, regulatory language, Final 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 final 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
Final Rule?
D. What Requirements Are We Adopting?
E. Why Is EPA Taking This Action?

[[Page 68243]]

II. Nonroad: General Provisions
A. Scope of Application
B. Emission Standards and Testing
C. Demonstrating Compliance
D. Other Concepts
III. Recreational Vehicles and Engines
A. Overview
B. Engines Covered by This Rule
C. Emission Standards
D. Testing Requirements
E. Special Compliance Provisions
F. Technological Feasibility of the Standards
IV. Permeation Emission Control
A. Overview
B. Vehicles Covered by This Provision
C. Permeation Emission Standards
D. Testing Requirements
E. Special Compliance Provisions
F. Technological Feasibility
V. Large Spark-ignition (SI) Engines
A. Overview
B. Large SI Engines Covered by This Rule
C. Emission Standards
D. Testing Requirements and Supplemental Emission Standards
E. Special Compliance Provisions
F. Technological Feasibility of the Standards
VI. Recreational Marine Diesel Engines
A. Overview
B. Engines Covered by This Rule
C. Emission Standards for Recreational Marine Diesel Engines
D. Testing Equipment and Procedures
E. Special Compliance Provisions
F. Technical Amendments
G. Technological Feasibility
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. Hearings (Part 1068, Subpart G)
VIII. General Test Procedures
A. General Provisions
B. Laboratory Testing Equipment
C. Laboratory Testing Procedures
D. Other Testing Procedures
IX. Projected Impacts
A. Environmental Impact
B. Cost Estimates
C. Cost Per Ton of Emissions Reduced
D. Economic Impact Analysis
E. Do the Benefits Outweigh the Costs of the Standards?
X. Public Participation
XI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act (RFA), as Amended by the Small
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5
U.S.C. 601 et seq.
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Congressional Review Act
K. Plain Language

I. Introduction

A. Overview

Emissions from the engines regulated in this rule contribute to
serious air-pollution problems, and will continue to do so in the
future absent regulation. These air pollution problems include exposure
to carbon monoxide (CO), ground-level ozone, and particulate matter
(PM), which can cause serious health problems, including premature
mortality and respiratory problems. Fine PM has also been associated
with cardiovascular problems, such as heart rate variability and
changes in fibrinogen (a blood clotting factor) levels, and hospital
admissions and mortality related to cardiovascular diseases. These
emissions also contribute to other serious environmental problems,
including visibility impairment and ecosystem damage. In addition, many
of the hydrocarbon (HC) pollutants emitted by these engines are air
toxics.
This rule addresses these air-pollution concerns by adopting
national emission standards for several types of nonroad engines and
vehicles that are currently unregulated. These include large spark-
ignition engines used in industrial and commercial applications such as
those used in forklifts and airport equipment; recreational spark-
ignition vehicles such as off-highway motorcycles, all-terrain
vehicles, and snowmobiles; and recreational marine diesel engines.\1\
These new standards are a continuation of the process of establishing
emission standards for nonroad engines and vehicles, under Clean Air
Act section 213(a).
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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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We conducted a study of emissions from nonroad engines, vehicles,
and equipment in 1991, as directed by the Clean Air Act, section 213(a)
(42 U.S.C. 7547(a)). Based on the results of that study, we determined
that emissions of oxides of nitrogen (NO_X), volatile organic
compounds, and CO from nonroad engines and equipment contribute
significantly to ozone and CO concentrations in more than one
nonattainment area (59 FR 31306, June 17, 1994). Given this
determination, section 213(a)(3) of the Act requires us to establish
(and from time to time revise) emission standards for those classes or
categories of new nonroad engines, vehicles, and equipment that in our
judgment cause or contribute to such air pollution. We have determined
that the engines covered by this final rule cause or contribute to such
air pollution (see the final finding for recreational vehicles and
nonroad spark-ignition engines over 19 kW published on December 7, 2000
(65 FR 76790), the final rule for marine diesel engines published on
December 29, 1999 (64 FR 73301)\2\, Section II of the preamble to the
proposed rule (66 FR 51098, October 5, 2001), this preamble, and the
Final Regulatory Support Document).
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\2\ This rule also found that PM emissions from marine diesel
engines contribute to PM nonattainment.
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Where we determine that other emissions from new nonroad engines,
vehicles, or equipment significantly contribute to air pollution that
may reasonably be anticipated to endanger public health or welfare,
section 213(a)(4) of the Act authorizes EPA to establish (and from time
to time revise) emission standards from those classes or categories of
new nonroad engines, vehicles, and equipment that cause or contribute
to such air pollution. Pursuant to section 213(a)(4) of the Act, we are
finalizing a finding that emissions from new nonroad engines, including
construction equipment, farm tractors, boats, locomotives, marine
engines, nonroad spark-ignition engines over 19 kW, recreational
vehicles (including off-highway motorcycles, all-terrain-vehicles, and
snowmobiles), significantly contribute to regional haze and visibility
impairment in federal Class I areas and where people live, work and
recreate. These engines, particularly recreational vehicles such as
snowmobiles, are significant emitters of pollutants that are known to
impair visibility in federal Class I areas (see Section I.E of this
preamble and the Final Regulatory Support Document). We have also
determined that engines covered by this final rule, particularly
recreational vehicles including snowmobiles, contribute to such
pollution. Thus, we are finalizing HC standards for snowmobiles to
reduce PM-related visibility impairment.

[[Page 68244]]

B. How Is This Document Organized?

This final rule covers engines and vehicles that vary in design and
use, and many readers may be interested in only one or two of the
applications. We have grouped engines by common application (for
example, recreational land-based engines, marine diesel recreational
engines, large spark-ignition engines used in commercial applications).
This document is organized in a way that allows each reader to focus on
the applications of particular interest.
Section II describes general provisions that are relevant to all of
the nonroad engines covered by this rulemaking. Section III through VI
present information specific to each of the affected nonroad
applications, 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
rulemaking. 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 these
sections.
Section IX summarizes the projected impacts and a discussion of the
benefits of this rule. Finally, Sections X and XI contain information
about public participation and various administrative requirements.
The remainder of this section summarizes the new requirements and
the air quality need for the rulemaking.

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

This final rule establishes regulatory programs for new nonroad
vehicles and engines not yet subject to EPA emission standards,
including the following engines:
[sbull]
Land-based spark-ignition recreational engines, including
those used in snowmobiles, off-highway motorcycles, and all-terrain
vehicles. For the purpose of this rule, we are calling this group of
engines ``recreational vehicles,'' even though all-terrain vehicles can
be used for commercial purposes.
[sbull]
Land-based spark-ignition engines rated over 19 kW,
including engines used in forklifts, generators, airport baggage tow
trucks, and various farm, construction, and industrial equipment. This
category also includes auxiliary marine engines, but does not include
propulsion marine engines or engines used in recreational vehicles. For
purposes of this rule, we refer to this category as ``Large SI
engines.''
[sbull]
Recreational marine diesel engines.
This final rule 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'' and
``imported'' that help define the scope of application of this rule is
in Section II of this preamble.
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\3\ For this final rule, 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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D. What Requirements Are We Adopting?

The fundamental requirement for nonroad engines and vehicles is
meeting EPA's emission standards. Section 213(a)(3) of the Act requires
that standards to control emissions related to ozone or CO 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. Section 213
(a)(4) of the Act requires that standards for emissions related to
other air pollution problems be appropriate and take into account
costs, noise, safety, and energy impacts of applying technology that
will be available. Other requirements such as applying for
certification, labeling engines, and meeting warranty requirements
define a process for implementing the program in an effective way.
With regard to Large SI engines, we are adopting a two-phase
program. The first phase of the standards go into effect in 2004 and
are the same as those adopted in October 1998 by the California Air
Resources Board for 2004. These standards will reduce combined HC and
NO_X emissions by nearly 75 percent, based on emission
measurements during steady-state operation. In 2007, we supplement
these standards by setting limits that will require optimizing the same
technologies and will base emission measurements on a transient test
cycle. New requirements for evaporative emissions and engine
diagnostics also start in 2007.
For recreational vehicles, we are adopting separate emission
standards for snowmobiles, off-highway motorcycles, and all-terrain
vehicles. For snowmobiles, we are adopting a first phase of standards
for HC and CO emissions based on a mixture of technologies ranging from
clean carburetion and engine modifications to direct fuel injection
two-stroke technology and some conversion to four-stroke engines, and
second and third phases of emission standards for snowmobiles that will
involve significant use of direct fuel injection two-stroke technology
and conversion to four-stroke engines. For off highway motorcycles and
all-terrain vehicles, we are adopting standards based mainly on moving
these engines from two-stroke to four-stroke technology with the use of
some secondary air injection. We are also adopting requirements to
address permeation emissions from all three types of recreational
vehicles.
The emission standards for recreational marine diesel engines are
comparable to those already established for commercial marine diesel
engines. Manufacturers generally have additional time to meet emission
standards for the recreational models and several specific rulemaking
provisions are tailored to the unique characteristics of these engines.
We are also adopting more stringent voluntary Blue Sky Series
emission standards for recreational marine diesel engines and Large SI
engines. Blue Sky Series emission standards are more stringent than the
mandatory emission standards and are intended to encourage the
introduction and more widespread use of low-emission technologies.
Manufacturers may be motivated to exceed emission 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 not adopting voluntary standards but rather providing consumers
with consumer labeling, which will provide information and opportunity
to buy lower-emissions models.
We have also conducted extensive analysis on the costs and benefits
of this rulemaking effort, with specific details found in Section IX
below and in the Final Regulatory Support Document. In summary, we
estimate that annually, the cost to manufacturers is approximately $210
million, the social gain is approximately $550 million, and the
quantified benefits are approximately $8 billion. Social gain is
defined as the economic cost of the rule minus the estimated fuels
savings. Quantified benefits reflect the health benefits primarily
associated with particulate matter controls.

E. Why Is EPA Taking This Action?

There are important public health and welfare reasons supporting
the new

[[Page 68245]]

emission standards. As described below and in the Final Regulatory
Support Document, these engines contribute to air pollution that causes
public health and welfare problems.
Nationwide, these engines and vehicles are a significant source of
mobile source air pollution. As described below, of all mobile source
emissions in 2000 they accounted for about 9 percent of HC emissions, 4
percent of CO emissions, 3 percent of NO_X emissions, and 2
percent of direct PM emissions. The emissions from Large SI engines
contributed 2 to 3 percent of the HC, NO_X, and CO emissions
from mobile sources in 2000. Recreational vehicles by themselves
account for about 6 percent of national mobile source HC emissions and
about 2 percent of national mobile source CO emissions. By reducing
these emissions, the standards will aid states facing ozone and CO air
quality problems, which can cause a range of adverse health effects,
especially in terms of respiratory disease and related illnesses. The
engine categories subject to this rule contribute to regional haze and
visibility impairment in Class I areas and near where people live, work
and recreate. Within national parks, emissions from snowmobiles in
particular contribute to ambient concentrations of fine PM, a leading
cause of visibility impairment. States are required to develop plans to
address visibility impairment in national parks, and the reductions
required in this rule would assist states in those efforts.
The standards will also help reduce acute exposure to CO and air
toxics for forklift operators, equipment users or riders, national and
state park attendants, and other people who may be at particular risk
because they operate or work or are otherwise in close proximity to
this equipment due to their occupation or as riders. Emissions from
these vehicles and equipment can be very high on a per-engine basis. In
addition, the equipment using these engines (especially forklifts) is
often operated in enclosed areas. Similarly, exposure to CO and air
toxics can be intensified for snowmobile riders who follow a group of
other riders along a trail, since those riders are exposed to the
emissions of all the other snowmobiles riding ahead.
When the emission standards are fully implemented in 2030, we
expect a 75-percent reduction in HC emissions, 82-percent reduction in
NO_X emissions, and 61-percent reduction in CO emissions, and
a 60-percent reduction in direct PM emissions from these engines,
equipment, and vehicles (see Section IX below). These emission
reductions will reduce ambient concentrations of CO, ozone, and PM
fine; fine particles are a public health concern and contributes to
visibility impairment. The standards will also reduce exposure for
people who operate or who work with or are otherwise in close proximity
to these engines and vehicles.
We believe technology can be applied to these engines that will
reduce emissions of these harmful pollutants. Manufacturers can reduce
two-stroke engine emissions by improving fuel management and
calibration. This can be achieved by making improvements to carbureted
fuel systems and/or converting to electronic and direct fuel injection.
In addition, many of the existing two-stroke engines in these
categories can be converted to four-stroke technology. Finally, there
are modifications that can be made to four-stroke engines, often short
of requiring catalysts, that can reduce emissions even further.
1. Health and Welfare Effects
Exposure to CO, ground-level ozone, and PM can cause serious
respiratory problems, including premature mortality and respiratory
problems. Fine PM has also been associated with cardiovascular
problems, such as heart rate variability and fibrinogen (a blood
clotting factor) levels, and hospital admissions and mortality related
to cardiovascular diseases. These emissions also contribute to other
serious environmental problems, including visibility impairment and
ecosystem damage. In addition, some of the HC pollutants emitted by
these engines are air toxics. (The health and welfare effects are
described in more detail in the Final Regulatory Support Document.)
CO 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.
Exposures to ozone has been linked to increased hospital admissions
and emergency room visits for respiratory problems.\4\ Repeated
exposure to ozone can increase susceptibility to respiratory infection
and lung inflammation. It can aggravate preexisting respiratory
diseases, such as asthma. Prolonged (6 to 8 hours), repeated exposure
to ozone can cause inflammation of the lung, impairment of lung defense
mechanisms, and possibly irreversible changes in lung structure, which
over time could lead to premature aging of the lungs and/or chronic
respiratory illnesses such as emphysema and chronic bronchitis.
Children, the elderly, asthmatics and outdoor workers are most at risk
from ozone exposure. Evidence also exists of a possible relationship
between daily increases in ozone levels and increases in daily
mortality levels. In addition to human health effects, ozone adversely
affects crop yield, vegetation and forest growth, and the durability of
materials.
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\4\ U.S. EPA Review of the National Ambient Air Quality
Standards for Ozone: Policy Assessment of Scientific and Technical
Information OAQPS Staff Paper. EPA-452/R-96-007. June 1996. A copy
of this document can be found in Docket A-99-06, Document II-A-22.
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PM, like ozone, has been linked to a range of serious respiratory
health problems.\5\ The key health effects 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 non-cancer
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.
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\5\ U.S. EPA 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. 1996.
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.
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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 and in places where people live
and work. Visibility effects are manifest in two principal ways: (1) as
local impairment (for example,

[[Page 68246]]

localized hazes and plumes) and (2) as regional haze. The emissions
from engines covered by this rule can contribute to both types of
visibility impairment.
The engines covered by this rule also emit air toxics that are
known or suspected human or animal carcinogens, or have serious non-
cancer health effects. These include benzene, 1,3-butadiene,
formaldehyde, acetaldehyde, and acrolein.
2. What Is the Inventory Contribution From the Nonroad Engines and
Vehicles That Would Be Subject to This Rule?
The contribution of emissions from the nonroad engines and vehicles
that will be subject to this final rule to the national inventories of
pollutants is considerable. To estimate nonroad engine and vehicle
emission contributions, we used the latest version of our NONROAD
emissions model, updated with information received during the public
comment period. 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 Final Regulatory Support Document.
Baseline emission inventory estimates for the year 2000 for the
categories of engines and vehicles covered by this rule are summarized
in Table I.E-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 rule contribute
about 9 percent, 3 percent, 4 percent, and 2 percent of HC,
NO_X, CO, and PM emissions, respectively, in the year 2000.
The results for Large SI engines indicate they contribute approximately
2 to 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 about 6
percent of HC emissions and 2 percent of CO from mobile sources.
Recreational marine diesel engines contribute less than 1 percent to
NO_X mobile source inventories. When only nonroad emissions
are considered, the engines and vehicles that will be subject to the
standards account for a larger share.
Our draft emission projections for 2020 and 2030 for the nonroad
engines and vehicles subject to this rule show that emissions from
these categories are expected to increase over time if left
uncontrolled. The projections for 2020 and 2030 are summarized in
Tables I.E-2 and I.E-3, respectively. The projections for 2020 and 2030
indicate that the categories of engines and vehicles covered by this
rule are expected to contribute approximately 25 percent, 10 percent, 5
percent, and 5 percent of mobile source HC, NO_X, CO, and PM
emissions, respectively, if left uncontrolled. Engine population growth
and the effects of other regulatory control programs are factored into
these projections. The relative importance of uncontrolled nonroad
engines in 2020 and 2030 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.
Regarding PM specifically, this information and information in
Section I.3(ii) below show that the engines being regulated in this
rule, snowmobiles and other recreational vehicles in particular,
contribute to PM concentrations that may reasonably be anticipated to
endanger public health and welfare both because of the health effects
associated with PM and because of the effects on visibility discussed
below.

Table I.E-1.--Modeled Annual Emission Levels for Mobile Source Categories in 2000
[Thousand short tons]
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NO_X HC CO PM
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Category Percent Percent Percent Percent
1000 tons of mobile 1000 tons of mobile 1000 tons of mobile 1000 tons of mobile
source source source source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total for engines subject to this final rule[hairsp][hairsp]*... 351 2.6 645 8.8 2,860 3.8 14.6 2.1
============
Highway Motorcycles............................................. 8 0.1 84 1.2 331 0.4 0.4 0.1
Nonroad Industrial SI £19 kW[hairsp][hairsp]*......... 308 2.3 226 3.1 1,734 2.3 1.6 0.2
Recreational SI[hairsp][hairsp]*................................ 5 0.0 418 5.7 1,120 1.5 12.0 1.7
Recreational Marine Diesel[hairsp][hairsp]*..................... 38 0.3 1 0.0 6 0.0 1 0.1
Marine SI Evap.................................................. 0 0.0 100 1.4 0 0.0 0 0.0
Marine SI Exhaust............................................... 32 0.2 708 9.7 2,144 2.8 38 5.4
Nonroad SI <19 kW............................................... 106 0.8 1,460 20.0 18,359 24.3 50 7.1
Nonroad diesel.................................................. 2,625 19.5 316 4.3 1,217 1.6 253 35.9
Commercial Marine Diesel........................................ 963 7.2 30 0.4 127 0.2 41 5.8
Locomotive...................................................... 1,192 8.9 47 0.6 119 0.2 30 4.3
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Total Nonroad................................................... 5,269 39 3,305 45 24,826 33 427 60
Total Highway................................................... 7,981 59 3,811 52 49,813 66 240 34
Aircraft........................................................ 178 1 183 3 1,017 1 39 6
------------
Total Mobile Sources............................................ 13,428 100 7,300 100 75,656 100 706 100
============
Total Man-Made Sources.......................................... 24,532 ......... 18,246 ......... 97,735 ......... 3,102 .........
============
Mobile Source percent of Total Man-Made Sources................. 55 ......... 40 ......... 77 ......... 23
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 68247]]

Table I.E-2.--Modeled Annual Baseline Emission Levels for Mobile Source Categories in 2020
[thousand short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
NO_X HC CO PM
---------------------------------------------------------------------------------------
Category Percent Percent Percent Percent
1000 tons of mobile 1000 tons of mobile 1000 tons of mobile 1000 tons of mobile
source source source source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total for engines subject to this final rule*................... 547 8.8 1,305 24.1 4,866 5.6 34.1 5.2
============
Highway Motorcycles............................................. 14 0.2 142 2.6 572 0.7 0.8 0.1
Nonroad Industrial SI £ 19 kW*........................ 472 7.6 318 5.9 2,336 2.7 2.3 0.4
Recreational SI*................................................ 14 0.2 985 18.2 2,521 2.9 30.2 4.6
Recreational Marine Diesel*..................................... 61 1.0 2 0.0 9 0.0 1.6 0.2
Marine SI Evap.................................................. 0 0.0 114 2.1 0 0.0 0 0.0
Marine SI Exhaust............................................... 58 0.9 284 5.2 1,985 2.3 28 4.3
Nonroad SI < 19 Kw.............................................. 106 1.7 986 18.2 27,352 31.7 77 11.8
Nonroad Diesel.................................................. 1,791 28.8 142 2.6 1,462 1.7 261 40.0
Commercial Marine Diesel........................................ 819 13.2 35 0.6 160 0.2 46 7.0
Locomotive...................................................... 611 9.8 35 0.6 119 0.1 21 3.2
------------
Total Nonroad................................................... 3,932 63 2,901 54 35,944 42 467 71
Total Highway................................................... 2,050 33 2,276 42 48,906 56 145 22
Aircraft........................................................ 232 4 238 4 1,387 2 43 7
------------
Total Mobile Sources............................................ 6,214 100 5,415 100 86,237 100 655 100
============
Total Man-Made Sources.......................................... 16,190 ......... 15,475 ......... 109,905 ......... 3,039 .........
============
Mobile Source percent of Total Man-Made Sources................. 38 ......... 35 ......... 79 ......... 22 .........
--------------------------------------------------------------------------------------------------------------------------------------------------------

Table I.E-3.--Modeled Annual Emission Levels for Mobile Source Categories in 2030
[Thousand short tons]
--------------------------------------------------------------------------------------------------------------------------------------------------------
NO_X HC CO PM
---------------------------------------------------------------------------------------
Category Percent Percent Percent Percent
1000 tons of mobile 1000 tons of mobile 1000 tons of mobile 1000 tons of mobile
source source source source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total for engines subject to this final rule*................... 640 10.0 1,411 23.5 5,363 5.4 36.5 4.8
============
Highway Motorcycles............................................. 17 0.3 172 2.9 693 0.7 1.0 0.1
Nonroad Industrial SI £ 19 kW*........................ 553 8.6 371 6.2 2,703 2.7 2.7 0.4
Recreational SI*................................................ 15 0.2 1,038 17.3 2,649 2.7 31.9 4.2
Recreational Marine Diesel*..................................... 72 1.1 2 0.0 11 0.0 1.9 0.3
Marine SI Evap.................................................. 0 0.0 122 2.0 0 0.0 0 0.0
Marine SI Exhaust............................................... 64 1.0 269 4.5 2,083 2.1 29 3.8
Nonroad SI < 19 kW.............................................. 126 2.0 1,200 20.0 32,310 32.4 93 12.3
Nonroad Diesel.................................................. 1,994 31.0 158 2.6 1,727 1.7 306 40.4
Commercial Marine Diesel........................................ 1,166 18.1 52 0.9 198 0.2 74 9.8
Locomotive...................................................... 531 8.3 30 0.5 119 0.1 18 2.4
------------
Total Nonroad................................................... 4,521 70 3,242 54 41,800 42 557 74
Total Highway................................................... 1,648 26 2,496 42 56,303 56 158 21
Aircraft........................................................ 262 4 262 4 1,502 2 43 6
------------
Total Mobile Sources............................................ 6,431 100 6,000 100 99,605 100 758 100
============
Total Man-Made Sources.......................................... 16,639 -- 17,020 -- 123,983 -- 3,319 --
============
Mobile Source percent of Total Man-Made Sources................. 39 -- 35 -- 80 -- 23 --
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 68248]]

3. Why are Controls to Protect against CO Nonattainment and to Protect
Visibility Needed From the Nonroad Engines and Vehicles That Would Be
Subject to This Rule?
i. Why are We Controlling CO Emissions from Nonroad Engines and
Vehicles that Would be Subject to this Rule?
Engines subject to this rule contributed about 3.8 percent of CO
from mobile sources in 2000. Over 22.4 million people currently live in
the 13 nonattainment areas for the CO National Ambient Air Quality
Standard (NAAQS). Industry association comments questioned the need for
CO control and snowmobile contribution, in particular. First, the
statute envisions that categories should be considered in determining
contribution because otherwise, it would be possible to continue to
arbitrarily divide subcategories until the contribution from any
subcategory becomes minimal while the cumulative effect of the air
pollution remains. EPA previously determined that the category of Large
SI engines and recreational vehicles cause or contribute to ambient CO
and ozone in more than one nonattainment area (65 FR 76790, December 7,
2000). EPA also examined recreational vehicles separately and found
that recreational vehicles subject to this rule contribute to CO
nonattainment in areas such as Los Angeles, Phoenix, Anchorage, and Las
Vegas (see RSD chapter 2). Thus, if considered as a category,
recreational vehicles contribute to CO nonattainment.\6\ Moreover, when
we examined snowmobiles separately, they met the contribution criteria.
---------------------------------------------------------------------------

\6\ Likewise, Large SI equipment and recreational marine diesel
engines also contribute to CO in nonattainment areas.
---------------------------------------------------------------------------

The International Snowmobile Manufacturers Association (ISMA)
stated in its public comments that snowmobiles in particular are not
operated in many of the CO nonattainment areas because of lack of snow
(although they may be stored in those areas). The commenters also
contended that northern areas have experienced improved CO air quality.
Many areas are making progress in improving their air quality. However,
an area cannot be redesignated to attainment until it can show EPA that
it has had air quality levels within the level required for attainment
and that it has a plan in place to maintain such levels. Until areas
have been redesignated, they remain nonattainment areas.\7\ Snowmobiles
contribute to CO nonattainment in more than one of these areas.
---------------------------------------------------------------------------

\7\ There are important reasons to focus on redesignation
status, as compared to just current air quality. Areas with a few
years of attainment data can and often do have exceedances following
such years of attainment because of several factors including
different climatic events during the later years, increases in
inventories, etc. Control of emissions from nonroad engines can help
to avoid potential future air quality problems.
---------------------------------------------------------------------------

Snowmobiles have relatively high per-engine CO emissions, and they
can be a significant source of ambient CO levels in CO nonattainment
areas. Despite the fact that snowmobiles are largely banned in CO
nonattainment areas by the state of Alaska, the state estimated (and a
National Research Council study confirmed) that snowmobiles contributed
0.3 tons/day in 2001 to Fairbanks' CO nonattainment area or 1.2 percent
of a total inventory of 23.3 tons per day in 2001.\8,9\ While Fairbanks
has made significant progress in reducing ambient CO concentrations,
existing climate conditions make achieving and maintaining attainment
challenging. Anchorage, AK, reports a similar contribution of
snowmobiles to their emissions inventories (0.34 tons per day in 2000).
Furthermore, a recent National Academy of Sciences report concludes
that ``Fairbanks will be susceptible to violating the CO health
standards for many years because of its severe meteorological
conditions. That point is underscored by a December 2001 exceedance of
the standard in Anchorage which had no violations over the last 3
years.''\10\
---------------------------------------------------------------------------

\8\ 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.
\9\ National Research Council. The Ongoing Challenge of Managing
Carbon Monoxide Pollution in Fairbanks, AK. May 2002. Docket A-2000-
01, Document No. IV-A-115.
\10\ National Research Council. The Ongoing Challenge of
Managing Carbon Monoxide Pollution in Fairbanks, AK. May 2002.
Docket A-2000-01, Document IV-A-115.
---------------------------------------------------------------------------

ISMA commented that it agreed with EPA that there is a snowmobile
trail within the Spokane, WA, CO nonattainment area, although they
noted that snowmobile operation alone would not result in CO
nonattainment. However, emissions from regulated categories need only
contribute to, not themselves cause, nonattainment. Concentrations of
NAAQS-related pollutants are by definition a result of multiple sources
of pollution.
Several states that contain CO nonattainment areas also have large
populations of registered snowmobiles and nearby snowmobile trails in
adjoining counties, which are an indication of where they are operated
(see Table I.E-4). EPA requested comment on the volume and nature of
snowmobile use in these and other CO nonattainment areas. ISMA
commented on the proximity of trails to northern CO nonattainment
areas, assuming that snowmobiles are operated only on trails. A search
of the available literature indicates that snowmobiles are ridden in
areas other than trails. For example, a 1998 report by the Michigan
Department of Natural Resources indicates that from 1993 to 1997, of
the 146 snowmobile fatalities studied, 46 percent occurred on a state
or county roadway (another 2 percent on roadway shoulders) and 27
percent occurred on private lands. Furthermore, accident reports in CO
nonattainment area Fairbanks, AK, demonstrate that snowmobiles driven
on streets have collided with motor vehicles. On certain days there may
be concentrations of snowmobiles operated in nonattainment areas due to
public events such as snowmachine races (such as the Iron Dog Gold Rush
Classic, which finishes in Fairbanks, AK), during which snowmobiles
will be present and operated.

Table I.E-4.--Snowmobile Use in Selected CO Nonattainment Areas
----------------------------------------------------------------------------------------------------------------
2001 State
City and state CO nonattainment classification snowmobile
population\a\
----------------------------------------------------------------------------------------------------------------
Anchorage, AK
Fairbanks, AK................. Serious...................................................... \b\ 35576
Spokane, WA................... Serious...................................................... 31532
Fort Collins, CO.............. Moderate..................................................... 32500
Medford, OR................... Moderate..................................................... 16809

[[Page 68249]]

Missoula, MT.................. Moderate..................................................... 23440
----------------------------------------------------------------------------------------------------------------
\a\ Source: ISMA U.S. Snowmobile Registration History, May 15, 2001; various studies prepared for state
snowmobile associations included in Docket A-2000-01.
\b\ Point of sale registration was not mandatory in Alaska prior to 1998, so the statewide registered population
is likely to underestimate the total population.

Exceedances of the 8-hour CO standard were recorded in three of
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.\11\ 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.\12\
---------------------------------------------------------------------------

\11\ 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.
\12\ Air Quality Criteria for Carbon Monoxide, U.S. 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.
---------------------------------------------------------------------------

In addition, there are 6 areas that have not been classified as
nonattainment where air quality monitoring indicated a need for CO
control. For example, CO monitors in northern locations such as Des
Moines, IA, and Weirton, WV/Steubenville, OH, registered levels above
the level of the CO standards in 1998.
ii. Why are Controls Needed From the Nonroad Engines and Vehicles
That Would Be Subject to this Rule to Protect Visibility?
(1) Visibility is Impaired by Fine PM and Precursor Emissions From
Nonroad Engines and Vehicles That Would Be Subject to This Rule.
Visibility can be defined as the degree to which the atmosphere is
transparent to visible light.\13\ Visibility degradation is an easily
noticeable effect of fine PM present in the atmosphere, and fine PM is
the major cause of reduced visibility in parts of the United States,
including many of our national parks and in places across the country
where people live, work, and recreate. Fine particles with significant
light-extinction efficiencies include organic matter, sulfates,
nitrates, elemental carbon (soot), and soil.
---------------------------------------------------------------------------

\13\ National Research Council, 1993. Protecting Visibility in
National Parks and Wilderness Areas. National Academy of Sciences
Committee on Haze in National Parks and Wilderness Areas. National
Academy Press, Washington, DC. This document is available on the
internet at http://www.nap.edu/books/0309048443/html/. See also U.S.
EPA Air Quality Criteria Document for Particulate Matter (1996) and
Review of the National Ambient Air Quality Standards for Particulate
Matter: Policy Assessment of Scientific and Technical Information.
These documents can be found in Docket A-99-06, Documents No. II-A-
23 and IV-A-130-32.
---------------------------------------------------------------------------

Visibility is an important effect because it has direct
significance to people's enjoyment of daily activities in all parts of
the country. Individuals value good visibility for the well-being it
provides them directly, both in where they live and work, and in places
where they enjoy recreational opportunities. Visibility is highly
valued in significant natural areas such as national parks and
wilderness areas, because of the special emphasis given to protecting
these lands now and for future generations.
To quantify changes in visibility, we compute a light-extinction
coefficient, which shows the total fraction of light that is decreased
per unit distance. Visibility can be described in terms of PM
concentrations, visual range, light extinction or deciview.\14\ In
addition to limiting the distance that one can see, the scattering and
absorption of light caused by air pollution can also degrade the color,
clarity, and contrast of scenes.
---------------------------------------------------------------------------

\14\ Visual range can be defined as the maximum distance at
which one can identify a black object against the horizon sky. It is
typically described in miles or kilometers. Light extinction is the
sum of light scattering and absorption by particles and gases in the
atmosphere. It is typically expressed in terms of inverse megameters
(Mm-1), with larger values representing worse visibility. The
deciview metric describes perceived visual changes in a linear
fashion over its entire range, analogous to the decibel scale for
sound. A deciview of 0 represents pristine conditions. Under many
scenic conditions, a change of 1 deciview is considered perceptible
by the average person.
---------------------------------------------------------------------------

Visibility effects are manifest in two main ways: as local
impairment (for example, localized hazes and plumes) and as regional
haze. In addition, visibility impairment has a time dimension in that
it might relate to a short-term excursion or to longer periods (for
example, worst 20 percent of days or annual average levels).
Local-scale visibility degradation is commonly seen as a plume
resulting from the emissions of a specific source or small group of
sources, or it is in the form of a localized haze such as an urban
``brown cloud.'' Plumes are comprised of smoke, dust, or colored gas
that obscure the sky or horizon relatively near sources. Impairment
caused by a specific source or small group of sources has been
generally termed as ``reasonably attributable.''
The second type of impairment, regional haze, results from
pollutant emissions from a multitude of sources located across a broad
geographic region. It impairs visibility in every direction over a
large area, in some cases over multi-state regions. Regional haze masks
objects on the horizon and reduces the contrast of nearby objects. The
formation, extent, and intensity of regional haze is a function of
meteorological and chemical processes, which sometimes cause fine
particulate loadings to remain suspended in the atmosphere for several
days and to be transported hundreds of kilometers from their sources.
On an annual average basis, the concentrations of non-anthropogenic
fine PM are generally small when compared with concentrations of fine
particles from anthropogenic sources. Anthropogenic contributions
account for about one-third of the average extinction coefficient in
the rural West and more than 80 percent in the rural East. Because of
significant differences related to visibility conditions in the eastern
and western U.S., we present information about visibility by region.
Furthermore, it is important to note that even in those areas with
relatively low

[[Page 68250]]

concentrations of anthropogenic fine particles, such as the Colorado
plateau, small increases in anthropogenic fine particle concentrations
can lead to significant decreases in visual range. This is one of the
reasons Class I areas have been given special consideration under the
Clean Air Act.
Nonroad engines that are subject to this final rule contribute to
ambient fine PM levels in two ways. First, they contribute through
direct emissions of fine PM. As shown in Table I.E-1, these engines
emitted 14,600 tons of PM (over 2 percent of all mobile source PM) in
2000. Second, these engines contribute to indirect formation of PM
through their emissions of gaseous precursors which are then
transformed in the atmosphere into particles. For example, these
engines emitted over 8 percent of the HC tons from mobile sources.
Furthermore, recreational vehicles, such as snowmobiles and all-terrain
vehicles emit high levels of organic carbon (as HC) on a per-engine
basis. Some organic emissions are transformed into particles in the
atmosphere and other volatile organics can condense if emitted in cold
temperatures, as is the case for emissions from snowmobiles, for
example. Organic carbon accounts for between 27 and 36 percent of
ambient fine particle mass depending on the area of the country.
(A) Visibility Impairment Where People Live, Work and Recreate
The secondary PM NAAQS is designed to protect against adverse
welfare effects such as visibility impairment. In 1997, the secondary
PM NAAQS was set as equal to the primary (health-based) PM NAAQS (62
Federal Register No. 138, July 18, 1997). EPA concluded that PM can and
does produce adverse effects on visibility in various locations,
depending on PM concentrations and factors such as chemical composition
and average relative humidity. In 1997, EPA demonstrated that
visibility impairment is an important effect on public welfare and that
visibility impairment is experienced throughout the U.S., in multi-
state regions, urban areas, and remote Federal Class I areas.
In many cities having annual mean PM_2.5 concentrations
exceeding 17 [mu]g/m\3\, improvements in annual average visibility
resulting from the attainment of the annual PM_2.5 standard
are expected to be perceptible to the general population (e.g., to
exceed 1 deciview). Based on annual mean monitored PM_2.5
data, many cities in the Northeast, Midwest, and Southeast as well as
Los Angeles would be expected to experience perceptible improvements in
visibility if the PM_2.5 annual standard were attained. For
example, in Washington, DC, where the IMPROVE monitoring network shows
annual mean PM_2.5 concentrations at about 19 [mu]g/m\3\
during the period of 1992 to 1995, approximate annual average
visibility would be expected to improve from 21 km (29 deciview) to 27
km (27 deciview), a change of 2 deciviews. The PM_2.5 annual
average in Washington, DC, was 18.9 [mu]g/m\3\ in 2000.
The updated monitored data and air quality modeling presented in
the RSD confirm that the visibility situation identified during the
NAAQS review in 1997 is still likely to exist. Thus, the determination
in the NAAQS rulemaking about broad visibility impairment and related
benefits from NAAQS compliance are still relevant. Levels above the
fine PM NAAQS cause adverse welfare impacts, such as visibility
impairment (both regional and localized impairment).
Furthermore, in setting the PM NAAQS, EPA acknowledged that levels
of fine particles below the NAAQS may also contribute to unacceptable
visibility impairment and regional haze problems in some areas, and
Clean Air Act Section 169 provides additional authorities to remedy
existing impairment and prevent future impairment in the 156 national
parks, forests and wilderness areas labeled as Class I areas.
In making determinations about the level of protection afforded by
the secondary PM NAAQS, EPA considered how the Section 169 regional
haze program and the secondary NAAQS would function together. Regional
strategies are expected to improve visibility in many urban and non-
Class I areas as well. The following recommendation for the National
Research Council, Protecting Visibility in National Parks and
Wilderness Areas (1993), addresses this point:
Efforts to improve visibility in Class I areas also would benefit
visibility outside these areas. Because most visibility impairment is
regional in scale, the same haze that degrades visibility within or
looking out from a national park also degrade visibility outside it.
The 1999-2000 PM_2.5 monitored values, which cover about
a third of the nation's counties, indicate that at least 82 million
people live in areas where long-term ambient fine particulate matter
levels are at or above 15 [mu]g/m\3\.\15\ Thus, these populations (plus
those who travel to those areas) could be experiencing visibility
impairment that is unacceptable, and emissions of PM and its precursors
from engines in these categories contribute to this unacceptable
impairment.\16\
---------------------------------------------------------------------------

\15\ 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.
\16\ These populations would obviously also be exposed to PM
concentrations associated with the adverse health impacts related to
PM_2.5.
---------------------------------------------------------------------------

Because the chemical composition of the PM affects visibility
impairment, we used EPA's Regulatory Model System for Aerosols and
Deposition (REMSAD)\17\ model to project visibility conditions in 2030
accounting for the chemical composition of the particles and to
estimate visibility impairment directly as changes in deciview. Our
projections included anticipated emissions from the engines subject to
this rule, and although our emission predictions reflected our best
estimates of emissions projections at the time the modeling was
conducted, we now have new estimates, as discussed in the RSD Chapter
1. Based on public comment for this rule and new information, we have
revised our emissions estimates in some categories downwards and other
categories upwards; however, on net, we believe the modeling
underestimates the PM air quality levels that would have been predicted
if new inventories were used.
---------------------------------------------------------------------------

\17\ 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/disel.htm#documents.
---------------------------------------------------------------------------

The most reliable information about the future visibility levels
would be in areas for which monitoring data are available to evaluate
model performance for a base year (e.g., 1996). Accordingly, we
predicted that in 2030, 49 percent of the population will be living in
areas where fine PM levels are above 15 [mu]g/m\3\ and monitors are
available.\18\ This can be compared with the 1996 level of 37 percent
of the population living in areas where fine PM levels are above 15
[mu]g/m\3\ and monitors are available. Thus, a substantial percent of
the population would experience unacceptable visibility impairment in
areas where they live, work and recreate.
---------------------------------------------------------------------------

\18\ 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.
---------------------------------------------------------------------------

As shown in Table I.E-5, in 2030, we expect visibility in the East
to be about

[[Page 68251]]

19 deciviews (or visual range of 60 kilometers) on average, with poorer
visibility in urban areas, compared to the visibility conditions
without man-made pollution of 9.5 deciviews (or visual range of 150
kilometers). Likewise, we expect visibility in the West to be about 9.5
deciviews (or visual range of 150 kilometers) in 2030, compared to the
visibility conditions without man-made pollution of 5.3 deciviews (or
visual range of 230 kilometers).
Nonroad engines contribute significantly to these effects. As shown
in Tables I.E-1 through I.E-3, nonroad engines emissions contribute a
large portion of the total PM emissions from mobile sources and
anthropogenic sources, in general. These emissions occur in and around
areas with PM levels above the annual PM_2.5 NAAQS. The
engines subject to the final rule will contribute to these effects.
They are estimated to emit 36,500 tons of direct PM in 2030, which is
1.1 percent of the total anthropogenic PM emissions in 2030. Similarly,
for PM precursors, the engines subject to this rule will emit 640,000
tons of NO_X and 1,411,000 tons HC in 2030, which are 3.8 and
8.3 percent of the total anthropogenic NO_X and HC emissions,
respectively, in 2030. Recreational vehicles in particular contribute
to these levels. In Table I.E-1 through I.E-3, we show that
recreational vehicles emitted about 1.7 percent of mobile source PM
emissions in 2000. Similarly, recreational vehicles are modeled to emit
over 4 percent of mobile source PM in 2020 and 2030. Thus, the
emissions from these sources contribute to the visibility impairment
modeled for 2030 summarized in the table.
Furthermore, 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 [mu]g/m\3\, the level of
the PM_2.5 NAAQS.\19\ 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.20, 21
---------------------------------------------------------------------------

\19\ 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
PM_2.5 Annual Mean and 98th Percentile 24-Hour Average
Concentrations. Docket No. A-2000-01, Document No. II-B-17.
\20\ This information also shows that snowmobiles contribute to
concentrations of fine PM that are above the primary health-related
NAAQS, which indicates that emissions from snowmobiles also
contribute to primary and secondary PM pollution that may reasonably
be anticipated to endanger public health and welfare.
\21\ Review of the National Ambient Air Quality Standards for
Particulate Matter: Policy Assessment for Scientific and Technical
Information, OAQPS Staff Paper, EPA-452[bs]R-96-
013, July, 1996, at IV-7. This document is available from Docket A-
99-06, Document II-A-23.

Table I.E-5--Summary of 2030 National Visibility Conditions Based on
REMSAD Modeling
[Deciviews]
------------------------------------------------------------------------
Predicted 2030
visibility b Natural
Regions a (annual background
average) visibility
------------------------------------------------------------------------
Eastern U.S............................. 18.98 9.5
Urban............................... 20.48
Rural............................... 18.38
Western U.S............................. 9.54 5.3
Urban............................... 10.21
Rural............................... 9.39
------------------------------------------------------------------------
a Eastern and Western Regions are separated by 100 degrees north
longitude. Background visibility conditions differ by region.
b The results incorporate earlier emissions estimates from the engines
subject to this rule, as discussed in the Final Regulatory Support
Document. We have revised our estimates both upwards for some
categories and downwards for others based on public comment and
updated information; however, we believe that the net results would
underestimate future PM emissions.

(B) Visibility Impairment in Class I Areas
The Clean Air Act establishes 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 this rule, EPA
established a ``natural visibility'' goal. In that rule, EPA also
encouraged the States to work together in developing and implementing
their air quality plans. The regional haze program is focused on long-
term emissions decreases from the entire regional emissions inventory
comprised of major and minor stationary sources, area sources and
mobile sources. The regional haze program is designed to improve
visibility and air quality in our most treasured natural areas from
these broad sources. At the same time, control strategies designed to
improve visibility in the national parks and wilderness areas will
improve visibility over broad geographic areas. In the 1997 PM NAAQS
rulemaking, EPA also anticipated the need in addition to the NAAQS and
Section 169 regional haze program to continue to address localized
impairment that may relate to unique circumstances in some Western
areas. For mobile sources, there is a need for a Federal role in
reduction of those emissions, particularly because mobile source
vehicles are regulated primarily at the federal level.
Visibility impairment is caused by pollutants (mostly fine
particles and precursor gases) directly emitted to the 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.
Visibility impairment is caused by both regional haze and localized
impairment. As described above, regional haze is caused

[[Page 68252]]

by the emission from numerous sources located over a wide geographic
area.\22\
---------------------------------------------------------------------------

\22\ U.S. EPA 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. 1996.
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.
---------------------------------------------------------------------------

Because of evidence that fine particles are frequently transported
hundreds of miles, all 50 states, including those that do not have
Class I areas, 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 (64 FR 35722.
July 1, 1999). The rule requires states to develop long-term strategies
including enforceable measures designed to meet reasonable progress
goals toward natural visibility conditions. 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.\23\
---------------------------------------------------------------------------

\23\ In a recent case, American Corn Growers Association v. EPA,
291 F. 3d 1 (D.C. Cir 2002), the court vacated the BART provisions
of the Regional Haze rule, but the court denied industry's challenge
to EPA's requirement that state's SIPs provide for reasonable
progress towards achieving natural visibility conditions in national
parks and wilderness areas and the ``no degradation'' requirement.
Industry did not challenge requirements to improve visibility on the
haziest 20 percent of days. A copy of this decision can be found in
Docket A-2000-01, Document IV-A-113.
---------------------------------------------------------------------------

In the PM air quality modeling described above, we also modeled
visibility conditions in the Class I areas, and we summarize the
results by region in Table I.E-6.

Table I.E-6--Summary of 2030 Visibility Conditions in Class I Areas
Based on REMSAD Modeling
[Annual Average Deciview]
------------------------------------------------------------------------
Natural
Region a Predicted 2030 background
visibility b visibility
------------------------------------------------------------------------
Eastern .............. 9.5
Southeast............................... 25.02 ..............
Northeast/Midwest....................... 21.00 ..............
Western .............. 5.3
Southwest............................... 8.69 ..............
California.............................. 11.61 ..............
Rocky Mountain.......................... 12.30 ..............
Northwest............................... 15.44 ..............
-----------------
National Class I Area Average....... 14.04 ..............
------------------------------------------------------------------------
a Regions are depicted in Figure VI-5 in the Regulatory Support Document
for the highway Heavy Duty Engine/Diesel Fuel RIA (EPA 420-R-00-026,
December 2000.) Background visibility conditions differ by region:
Eastern natural background is 9.5 deciviews (or visual range of 150
kilometers) and in the West natural background is 5.3 deciviews (or
visual range of 230 kilometers).
b The results incorporate earlier emissions estimates from the engines
subject to this rule, as discussed in the Final Regulatory Support
Document. We have revised our estimates both upwards for some
categories and downwards for others based on public comment and
updated information; however, we believe that the net results
underestimate future PM emissions.

Nonroad engines represent a sizeable portion of the total inventory
of anthropogenic emissions related to PM2.5, as shown in the tables
above. Numerous types of nonroad engines may operate near Class I areas
(e.g., mining equipment, recreational vehicles, and agricultural
equipment). We have reviewed contributions from snowmobile in
particular.
Emissions from nonroad engines, in particular snowmobiles,
contribute significantly to visibility impairment in Class I areas.\24\
Visibility and PM monitoring data are available for eight 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.\25\ Fine particle monitoring data
for these parks are set out in Table I.E-7. This table shows the number
of monitored days in the winter that fell within the 20-percent worst
visibility days for each of these eight parks. Monitors collect data 2
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 worst
visibility days during a year which are tracked as the primary focus of
regulatory efforts.\26\ 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 Alaska, the snowmobile season is October 1 to
April 30.
---------------------------------------------------------------------------

\24\ The results incorporate earlier emissions estimates from
the engines subject to this rule, as discussed in the Final
Regulatory Support Document. We have revised our estimates both
upwards for some categories and downwards for others based on public
comment and updated information; however, we believe that the net
results would underestimate future PM emissions.
\25\ No data were available at five additional parks where
snowmobiles are also commonly used: Black Canyon of the Gunnison,
CO, Grand Teton, WY, Northern Cascades, WA, Theodore Roosevelt, ND,
and Zion, UT.
\26\ 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.

[[Page 68253]]

Table I.E-7--Winter Days That Fall Within the 20 Percent Worst Visibility Days At National Parks Used by
Snowmobiles
----------------------------------------------------------------------------------------------------------------
Number of sampled wintertime days within 20
percent worst visibility days (maximum of 21
NPS unit States out of 104 monitored 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 Area MN...................... 2 5 1 5
(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.

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.'' \27\ We examined future air quality predictions to whether the
emissions from recreational vehicles, such as snowmobiles, contribute
to regional visibility impairment in Class I areas. We present results
from the future air quality modeling described above for these Class I
areas in addition to inventory and air quality measurements.
Specifically, in Table I.E-8, we summarize the expected future
visibility conditions in these areas without these regulations.
---------------------------------------------------------------------------

\27\ 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 I.E-8--Estimated 2030 Visibility in Selected Class I Areas a,b
----------------------------------------------------------------------------------------------------------------
Natural
Predicted 2030 background
visibility visibility
Class I area County State (annual (annual
average average
deciview) deciview)
----------------------------------------------------------------------------------------------------------------
Eastern areas ..................... ..................... .............. 9.5
Acadia............................ Hancock Co........... ME................... 23.42 ..............
Boundary Waters................... St. Louis Co......... MN................... 22.07 ..............
Voyageurs......................... St. Louis Co......... MN................... 22.07 ..............
Western areas ..................... ..................... .............. 5.3
Grand Teton NP.................... Teton Co............. WY................... 11.97 ..............
Kings Canyon...................... Fresno Co............ CA................... 10.39 ..............
Mount Rainier..................... Lewis Co............. WA................... 16.19 ..............
Rocky Mountain.................... Larimer Co........... CO................... 8.11 ..............
Sequoia-Kings..................... Tulare Co............ CA................... 9.36 ..............
Yellowstone....................... Teton Co............. WY................... 11.97 ..............
----------------------------------------------------------------------------------------------------------------
a Natural background visibility conditions differ by region because of differences in factors such as relative
humidity: Eastern natural background is 9.5 deciviews (or visual range of 150 kilometers) and in the West
natural background is 5.3 deciviews (or visual range of 230 kilometers).
b The results incorporate earlier emissions estimates from the engines subject to this rule. We have revised our
estimates both upwards for some categories and downwards for others based on public comment and updated
information; however, on net, we believe that HD07 analyses would underestimate future PM emissions from these
categories.

The information presented in Table I.E-7 shows that visibility data
support a conclusion that there are at least 8 Class I Areas (7
national parks and one wilderness area) frequented by snowmobiles with
one or more wintertime days within the 20-percent worst visibility days
of the year, and in many cases several days. 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 worst visibility monitored days,
2 of those days occurred during the wintertime when snowmobile
emissions such as hydrocarbons contributed to visibility impairment.
The information in Table I.E-8 shows that these areas also are
predicted to have high annual average deciview levels in the future.
Emissions from snowmobiles and other recreational vehicles, as well as
other nonroad engines contributed to these levels.\28\
---------------------------------------------------------------------------

\28\ See Chapter 1 in the RSD for a discussion or U.S. EPA
Technical Support Document for Heavy-duty Engine and Vehicle
Standards and Highway Diesel Fuel Sulfur Control Requirements--Air
Quality Modeling Analyses December 2000. Docket No. A-2000-01,
Docket Number IV-A-218. This document is also avaiable at
www.epa.gov/otaq/hdmodels.htm.

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

[[Page 68254]]

Ambient concentrations of fine particles are the primary pollutant
responsible for visibility impairment. The classes of fine particles
principally responsible for visibility impairment are 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.\29\
---------------------------------------------------------------------------

\29\ 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.
---------------------------------------------------------------------------

In the winter months, HC emissions from snowmobiles can be
significant, and these HC emissions can be more than half of the
organic carbon fraction of fine particles which are largely responsible
for visibility impairment. In Yellowstone, a park with high snowmobile
usage during the winter months, snowmobile HC emissions can exceed 500
tons per year, as much as several large stationary sources.\30\ Other
parks with less snowmobile traffic are also impacted although to a
lesser extent by these HC emissions.\31\
---------------------------------------------------------------------------

\30\ Emissions of NO_X from snowmobiles contribute to
the total amount of particulate nitrate, although the total
NO_X emissions from snowmobiles are considerably less than
HC or direct PM emissions from these engines.
\31\ 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 I.E-9 shows estimated 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).

Table I.E-9.--Winter Season Snowmobile Emissions
[tons; 1999 Winter Season]
------------------------------------------------------------------------
NPS unit HC CO NO_X PM
------------------------------------------------------------------------
Denali NP & Preserve............ X standard for snowmobiles. This
standard will essentially cap NO_X emissions from these
engines to prevent backsliding. We are not promulgating standards that
would require substantial reductions in NO_X because we
believe that standards which force substantial NO_X
reductions would likely not lead to reductions in PM and may in fact
increase PM levels. NO_X emissions from snowmobiles are very
small, particularly compared to levels of HC. In fact, technologies
that reduce HC and CO are likely to increase levels of NO_X
and vice versa, because technologies to reduce HC and CO emissions
would result in leaner operation. A lean air and fuel mixture causes
NO_X emissions to increase. These increases are minor,
however, compared to the reductions of HC (and therefore PM) that
result from these techniques.
On the other hand, substantial control of NO_X emissions
may have the counter-effect of increasing HC emissions and the greater
PM emissions associated with those HC emissions. The only way to reduce
NO_X emissions from four-stroke engines (at the same time as
reducing HC and CO levels) would be to use a three-way catalytic
converter. We do not have enough information at this time on the
durability or safety implications of using a three-way catalyst with a
four-stroke engine in snowmobile applications. Three-way catalyst
technology is well beyond the technology reviewed for this rule and
would need substantial additional review before being contemplated for
snowmobiles. Thus, given the overwhelming level of HC compared to
NO_X, and the secondary PM expected to result from these
levels, it would be premature and possibly counterproductive to
promulgate NO_X standards that require significant
NO_X reductions from snowmobiles at this time. We have
therefore decided to structure our long term HC+NO_X standard
for 2012 and later model year snowmobiles to require only a cap on
NO_X emissions from the advanced technology engines which
will be the dominant technology in the new snowmobiles certified at
that time.

II. Nonroad: General Provisions

This section describes general provisions concerning the emission
standards adopted in this final rule and the ways in which a
manufacturer shows compliance with these standards. Clean Air Act
section 213(a)(3) 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. Section
202(a)(4) provides further authority to adopt standards for pollution
beyond that regulated under section 202(a)(3). In addition to emission
standards, this document describes a variety of other provisions
necessary for implementing the proposed emission-control program in an
effective way, such as applying for certification, labeling engines,
and meeting warranty requirements.
The discussions in this section are general and are meant to cover
all the nonroad engines and vehicles subject to the new standards. In
this Section II, the term engine is sometimes used to include both
nonroad engines and nonroad vehicles. Refer to the discussions of
specific programs, contained in Sections III through VI, to determine
whether the regulations are being applied to the entire vehicle or just
the engine, as well as for more information about specific requirements
for different categories of nonroad engines and vehicles.
This section describes general nonroad provisions related to
certification prior to sale or introduction into commerce. Section VII
describes several compliance provisions that apply generally to nonroad
engines, and Section VIII similarly describes general testing
provisions.

A. Scope of Application

This final rule covers recreational marine diesel engines, nonroad
spark-ignition engines rated over 19 kW, and recreational spark-
ignition vehicles introduced into commerce in the United States. The
following sections describe generally when emission standards apply to
these products. These provisions are generally consistent with prior
nonroad and motor-vehicle rulemakings. Refer to the specific program
discussion below for more information about the scope of application
and timing of new standards.
1. What Engines and Vehicles Are Subject to the Standards?
The scope of this rule is broadly set by Clean Air Act section
213(a), which instructs us to set emission standards for new nonroad
engines and new nonroad vehicles. Generally speaking, this rule is
intended to cover all new engines and vehicles in the categories listed
above (including any associated equipment or vessels) for their entire
useful lives, as defined in the regulations.\33\ Once the emission
standards apply to a group of engines or vehicles, manufacturers of a
new engine must have an approved certificate of conformity from us
before selling them in the United States.\34\ This also applies to
importation by any person and any other means of introducing new
engines and vehicles into commerce. We also require equipment
manufacturers that install engines from other companies to install only
certified engines into new equipment once emission standards

[[Page 68256]]

apply. The information we require of manufacturers applying for
certification (with the corresponding engine labels) provides assurance
that manufacturers have met their obligation to make engines that meet
emission standards over the useful life we specify in the regulations.
---------------------------------------------------------------------------

\33\ For recreational vehicles, we are adopting vehicle-based
standards. For these applications, the term ``engine'' in this
document applies equally to the vehicles.
\34\ The term ``manufacturer'' includes any individual or
company that manufactures any new engine for sale or otherwise
introduces a new engine into commerce in the United States. It also
includes importers for resale.
---------------------------------------------------------------------------

2. How Do I Know if My Engine or Equipment Is New?
We are defining ``new'' consistent with previous rulemakings. We
will consider a nonroad engine (or nonroad equipment) to be new until
its title has been transferred to the ultimate purchaser or the engine
has been placed into service. This definition applies 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 will be considered new until their title
has been transferred to an ultimate buyer. In Section II.B.1 we
describe how to determine the model year of individual engines and
vehicles.
To further clarify the definition of new nonroad engine, we specify
that a nonroad engine, vehicle, or equipment is placed into service
when it is used for its intended purpose. An engine subject to emission
standards is used for its functional purpose when it is installed in 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 our
approach is reasonable because the practice of adapting used highway or
land-based nonroad engines may become more common if these engines are
not subject to emission standards.
In summary, an engine may be subject to emission 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 an automobile or a category of nonroad equipment subject
to different emission standards
. Installed in new nonroad equipment, regardless of the age
of the engine
. Imported (freshly manufactured or used) and was originally
manufactured after the effective date of our standards
3. When Do Imported Engines Need To Meet Emission Standards?
The emission standards apply to all new engines sold in the United
States. Consistent with Clean Air Act section 216, engines that are
imported by any person, whether freshly manufactured or used are
considered ``new'' engines.\35\ Thus, we 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 manufactured after our standards begin
to apply need an EPA-issued certificate of conformity to clear customs,
with limited exemptions (as described below).
---------------------------------------------------------------------------

\35\ The definition in Clean Air Act section 216 applies
specifically to ``new motor vehicles,'' but we have interpreted
``new nonroad engine'' consistently with the definition in section
216.
---------------------------------------------------------------------------

An engine or marine vessel, recreational vehicle, or other piece of
nonroad equipment that was built after emission standards take effect
cannot be imported without a currently valid certificate of conformity.
We would consider it to be a new engine, vehicle, or vessel, which
would trigger a requirement 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 vessel 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 or vehicles
abroad, transferring their title, and then importing them as used
vessels or vehicles.
Imported engines are generally subject to emission standards.
However, we are not adopting a definition of ``import'' in this
regulation. We will defer to the U.S. Customs Service for
determinations of when an engine or vehicle is imported into the U.S.
4. Do the Standards Apply to Exported Engines or Vehicles?
Engines or vehicles intended for export are generally not required
to meet the emission standards or other requirements adopted in this
rule. However, engines that will be exported and subsequently re-
imported into the United States must be covered by a certificate of
conformity. For example, this would occur 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 the modification is complete. 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. We also do not exempt engines exported to countries
that share our emission standards.
5. Are Any New Engines or Vehicles in the Applicable Categories Not
Subject to Emission Standards of This Rule?
We are extending our basic nonroad exemptions to the engines and
vehicles covered by this rulemaking. 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
emission standards do not apply to them. Refer to the program
discussions below for a description of how these exclusions or
exemptions apply for different categories of engines.

B. Emission Standards and Testing

1. Which Pollutants Are Covered by Emission Standards?
Engines subject to the exhaust emission standards must meet
standards based on measured levels of specified pollutants, such as
NO_X, HC, or CO, though not all engines have standards for
each pollutant. Diesel engines generally must also meet a PM emission
standard. In addition, there may be standards or other requirements for
crankcase, evaporative, or permeation emissions, as described below.
The emission standards are effective on a model-year basis. We
define model year much like we do for passenger cars. It generally
means either the calendar year or some other annual production period
based on the manufacturer's production practices. A model year may
include January 1 from only one year.

[[Page 68257]]

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 must meet emission standards for that model year. For
example, manufacturers producing new engines in the 2006 model year
need to comply with the 2006 standards. The model year of a particular
engine is determined based on the date that the engine is fully
assembled. In the case of recreational vehicles, this generally applies
to the final assembly of the whole vehicle, since the emission
standards apply to the vehicle. 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.
2. What Standards Apply to Crankcase, Evaporative, Permeation, and
Other Emissions?
Blow-by of combustion gases and the reciprocating action of the
piston can cause exhaust emissions to 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
hydrocarbons. We have long required that automotive engines prevent
emissions from their crankcases. Manufacturers typically do this by
routing crankcase vapors through a valve into the engine's air intake
system. We generally require in this rulemaking that engines control
crankcase emissions.
Vehicles with spark-ignition engines use fuel that is volatile and
the unburned fuel can be released into the ambient air. We are adopting
standards to limit evaporative emissions from the fuel. Evaporative
emissions result from heating gasoline or other volatile fuels in a
tank that is vented to the atmosphere or from permeation through
plastic fuel tanks and rubber hoses. Section IV describes the
permeation standards for recreational vehicles. Section V provides
additional information on the evaporative emission standards for Large
SI engines.
We are also adopting a general requirement that all engines subject
to this final rule may not cause or contribute to an unreasonable risk
to public health, welfare, or safety, especially with respect to
noxious or toxic emissions that may increase as a result of emission-
control technologies. The regulatory language has been modified
consistent with the alternate language suggested in the proposal. This
alternate language implements sections 202(a)(4) and 206(a)(3) of the
Act and clarifies that the purpose of this requirement is to prevent
control technologies that would cause unreasonable risks, rather than
to prevent trace emissions of any noxious compounds. For example, this
requirement would prevent the use of emission-control technologies that
produce high levels of pollutants for which we have not set emission
standards, but nevertheless pose a risk to the public. However, it
should be noted that this would generally not apply to exhaust gas
recirculation systems on gasoline- or diesel-fueled engines.
3. What Duty Cycles Is EPA Adopting 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 is generally derived from
typical operation from the field, is critical in evaluating the likely
emissions performance of engines designed to emission standards.
Testing for recreational marine diesel engines and Large SI engines may
also include additional operation not included in the specific duty
cycles.
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. Those sections
also include information regarding testing provisions that do not rely
on specific operating cycles (i.e., field-testing, not-to exceed
testing, and evaporative testing).
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 an appropriate level of emission
control for the whole range of adjustability. Manufacturers must
therefore show that their engines meet emission standards over the full
adjustment range. Manufacturers must also provide a physical stop to
prevent adjustment outside the established range. Operators are then
prohibited by the anti-tampering provisions from adjusting engines
outside this range.
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 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 for commercial
marine diesel engines. The general purposes of such programs are to
provide incentives to manufacturers to produce clean products, as well
as to create market choices and opportunities for environmental
information for consumers regarding such products.
We are adopting voluntary Blue Sky Series standards for some of the
engines subject to this final rule. 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.

C. Demonstrating Compliance

We are adopting a compliance program to accompany the final
emission standards. This consists first of a process for demonstrating
that new engine models comply with the emission standards. In addition
to new-engine testing, several provisions ensure that emission-control
systems will continue to function over long-term

[[Page 68258]]

operation in the field. Most of these certification 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 Do I Certify My Engines?
We are adopting a certification process similar to that already
established for other nonroad 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, EPA issues a Certificate of
Conformity which allows the manufacturer to produce and sell the
engines described in the application in the U.S.
Manufacturers certify their engine models by grouping them into
engine families that have similar emission characteristics. The engine
family definition is fundamental to the certification process and to a
large degree determines the amount of testing required for
certification. The 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.
Engine manufacturers are 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
or the average service life. 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 generally consider this useful life
value in amount of operation to be a minimum value, requiring
manufacturers to comply for a longer period in those cases where their
engines operate longer than the minimum useful life.
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, manufacturers must 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 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 helps the manufacturer be sure that all engines within the
engine family are complying with emission standards. Manufacturers
estimate the rate of deterioration for each engine family over its
useful life and show that engines continue to meet standards after
incorporating the estimated deterioration. We may also test the engines
ourselves.
Manufacturers must include in their application for certification
the results of emission tests showing that the engine family meets
emission standards. In addition, we may ask the manufacturer to include
any additional data 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
forming the basis of the manufacturer's application are a robust
indicator of emission-control performance, rather than a spurious or
incidental test result.
We are adopting test-fuel specifications intended to represent in-
use fuels. Engines must be able to meet the standards on fuels with
properties anywhere in the specified ranges. The test fuel is generally
to be used for all testing associated with the regulations, including
certification, production-line testing, and in-use testing. Refer to
the program discussions below related to test fuel specifications.
We 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 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 don't limit the
maintenance an operator may perform; it merely limits the maintenance
that operators can 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 require every engine a
manufacturer produces from the engine family to have a label with basic
identifying information. The design and content of engine labels is
specified in the regulations.
2. What Warranty Requirements Apply to Certified Engines?
Consistent with our current emission-control programs,
manufacturers must provide a design and defect warranty covering
emission-related components for a minimum period specified in the
regulations. This minimum period is generally half of the useful life
period. The regulations also provide that the manufacturer's emission
warranty period could be adjusted to a value higher than the minimum
period for those cases where the manufacturer provides a longer
mechanical warranty for the engine or any of its components; this
includes extended warranties that are available for an extra price. Any
such adjustment would be dependent on the average service life of the
vehicle as well. The manufacturer generally does not need to include
scheduled maintenance or other routine maintenance under the emission
warranty. See the regulation language for a detailed description of the
components that are considered to be 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, however, if
the operator caused the component failure by misusing the engine or
failing to do necessary maintenance.
We are also adopting 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 Use Emission Averaging To Show That I Meet Emission Standards?
Many of our mobile source emission-control programs include
voluntary use of emission credits 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 improve the technological feasibility and reduce the cost of
achieving standards, allowing us to consider a more stringent emission
standard than might otherwise be

[[Page 68259]]

appropriate, including a compliance date for the standards earlier than
would otherwise be appropriate. Manufacturers gain flexibility in
product planning and 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 allows a manufacturer to certify one or more engine
families at emission levels above the applicable emission standards, as
long as the increased emissions from that engine family are offset by
one or more engine families certified below the applicable standards.
The over-complying engine families generate credits that are used by
the under-complying engine families. Compliance is determined taking
into account differences in production volume, power and useful life
among engine families. The average of all the engine families for a
particular manufacturer's production must be at or below the level of
the applicable emission standards. This calculation generally factors
in sales-weighted average power, production volume, and useful life.
Banking allows a manufacturer to generate emission credits and bank
them for future use in its own averaging program in later years.
Trading allows transfer of credits to another company.
In general, a manufacturer choosing to participate in an emission-
credit program certifies each participating engine family to a Family
Emission Limit. In its certification application, a manufacturer
determines 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 each engine in that
engine family. Emission credits are based on the difference between the
emission standard that applies to the family and the Family Emission
Limit. Manufacturers must meet the Family Emission Limit for all
emission testing of any engine in that family. At the end of the model
year, manufacturers must 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 may 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. Refer to the
program discussions below for more information about emission-credit
provisions for individual engine categories.
4. What Are the Production-Line Testing Requirements?
We are adopting production-line testing requirements for
recreational marine diesel engines, recreational vehicles, and Large SI
engines. Manufacturers must 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 a small subset of production-line engines in a
particular engine family (see Section VII.E). Production-line testing
requirements are already common to several categories of nonroad
engines as part of their emission-control program.
If an engine fails to meet an emission standard, the manufacturer
must modify it to bring that specific engine into compliance.
Manufacturers may adjust the engine family's Family Emission Limit to
take into account the results from production-line testing (if
applicable). If too many engines exceed emission standards, this
indicates it is more of a family-wide problem and the manufacturer must
correct the problem for all affected engines. The remedy 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 before producing more engines. The
remedy may also need to address engines already produced since the last
showing that production-line engines met emission standards.
The production-line testing programs for Large SI engines and for
recreational vehicles depend on the Cumulative Sum (CumSum) statistical
process for determining the number of engines a manufacturer needs to
test (see the regulations for the specific calculation methodology).
Each manufacturer generally selects engines randomly at the beginning
of each new quarter.\36\ 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. The Cumulative Sum program uses the
emission results to calculate the number of tests required for the
remainder of the year to reach a pass or fail determination for
production-line testing. If tested engines have emissions close to the
standard, the statistical sampling method calls for an increased number
of tests to show whether to make a pass or fail determination for the
engine family. 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.
---------------------------------------------------------------------------

\36\ We consider an engine to be randomly selected if it
undergoes normal assembly and manufacturing procedures. An engine is
not randomly selected if it has been built with any kind of special
components or procedures.
---------------------------------------------------------------------------

If an engine family fails the production-line testing criteria, we
may suspend the Certificate of Conformity. Under the CumSum approach,
individual engines can exceed the emission standards without causing
the whole engine family to exceed the production-line testing criteria.
The production-line testing criteria are designed to determine if there
is a problem that applies broadly across the engine family. Whether or
not the production-line testing criteria are met, manufacturers must
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.
The regulations allow us to reduce testing requirements for engine
families that consistently pass the production-line testing criteria.
For engine families that pass all of the production-line test
requirements 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 may be
limited to a single model year,

[[Page 68260]]

but manufacturers may continue to request reduced testing rates.
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. A manufacturer
may therefore 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 approve the plan, we will use these criteria
to determine when an engine family passes or fails the production-line
testing criteria. It is important to note that this allowance is
intended only as a flexibility, and is not intended 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 Emission-Related Installation Instructions?
Manufacturers selling loose engines to equipment manufacturers must
develop a set of emission-related installation instructions. These
instructions include anything the installer needs 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
or permeation emissions. We approve emission-related installation
instructions as part of the certification process. If equipment
manufacturers fail to follow the established emission-related
installation instructions, we will consider this tampering, which may
subject them to significant civil penalties. Refer to the program
discussions below for more information about specific provisions
related to installation instructions.
2. Are There Special Provisions for Small Manufacturers of These
Engines and Vehicles?
The scope of this rule includes many engine and vehicle
manufacturers that have previously not been subject to our mobile
source regulations or certification process. Some of these
manufacturers are small businesses, with unique concerns relating to
the compliance burden from the general regulating program. The sections
describing the emission-control program include discussion of special
compliance provisions designed to address this for the different engine
categories.

III. Recreational Vehicles and Engines

A. Overview

We are adopting new exhaust emission standards for snowmobiles,
off-highway motorcycles, and all-terrain vehicles (ATVs). The engines
used in these vehicles are a subset of nonroad SI engines.\37\ In our
program to set exhaust emission standards for nonroad spark-ignition
engines below 19 kW (Small SI), we excluded recreational vehicles
because they have different design characteristics and usage patterns
than certain other engines in the Small SI category. For example,
engines typically found in the Small SI category are used in lawn
mowers, chainsaws, trimmers, and other lawn and garden applications.
These engines tend to have low power outputs and operate at constant
loads and speeds, whereas recreational vehicles can have high power
outputs with highly variable engine loads and speeds. This suggests
that these engines should be regulated differently than Small SI
engines. In the same way, we treat snowmobiles, off-highway
motorcycles, and ATVs separately from our Large SI engine program,
which is described in Section V. Recreational vehicles that are not
snowmobiles, off-highway motorcycles, or ATVs, will be subject to the
standards that otherwise apply to small nonroad spark-ignition engines
(see Section III.B.2).
---------------------------------------------------------------------------

\37\ Almost all recreational vehicles are equipped with spark-
ignition engines. Any diesel engines used in these applications must
meet our emission standards for nonroad diesel engines.
---------------------------------------------------------------------------

We are adopting exhaust emission standards for HC and CO from all
recreational vehicles. We are adopting an additional requirement to
control NO_X from off-highway motorcycles and ATVs. We
believe that vehicle and engine manufacturers will be able to use
technology already established for other types of engines, such as
highway motorcycles, small spark-ignition engines, and marine engines,
to meet these standards. We recognize that some small businesses
manufacture recreational vehicles; we are therefore adopting several
special compliance provisions to reduce the burden of emission
regulations on small businesses.
1. What Are Recreational Vehicles and Who Makes Them?
We are adopting new exhaust emission standards for off-highway
motorcycles, ATVs, and snowmobiles. Eight large manufacturers dominate
the sales of these recreational vehicles. Of these eight manufacturers,
seven of them manufacture two or more of the three main types of
recreational vehicles. For example, there are four companies that
manufacture both off-highway motorcycles and ATVs. There are three
companies that manufacture ATVs and snowmobiles; one company
manufactures all three. These eight companies represent approximately
95 percent of all domestic sales of recreational vehicles.
a. Off-highway motorcycles. Motorcycles are two-wheeled, self-
powered vehicles that come in a variety of configurations and styles.
Off-highway motorcycles are similar in appearance to highway
motorcycles, but there are several important distinctions between the
two types of machines. Off-highway motorcycles are not street-legal and
are primarily operated on public and private lands over trails and open
areas. A significant number are used in competition events. Off-highway
motorcycles tend to be much smaller, lighter and more maneuverable than
their larger highway counterparts. They are equipped with relatively
small-displacement single-cylinder two- or four-stroke engines ranging
from 48 to 650 cubic centimeters (cc) in size. The exhaust systems for
off-highway motorcycles are distinctively routed high on the frame to
prevent damage from brush, rocks, and water. Off-highway motorcycles
are designed to be operated over varying surfaces, such as dirt, sand,
or mud, and are equipped with knobby tires to give better traction in
off-road conditions. Unlike highway motorcycles, off-highway
motorcycles have fenders mounted far from the wheels and closer to the
rider to keep dirt and mud from spraying the rider and clogging between
the fender and tire. Off-highway motorcycles are also equipped with
more advanced suspension systems than those for highway motorcycles.
This allows the operator to ride over obstacles and make jumps safely.
Five companies dominate sales of off-highway motorcycles. They are
long-established, large corporations that manufacture several different
products including highway and off-highway motorcycles. These five
companies account for 90 to 95 percent of all

[[Page 68261]]

domestic sales of off-highway motorcycles. There are also several
relatively small companies that manufacture off-highway motorcycles,
many of which specialize in competition machines.
b. All-terrain vehicles. The earliest ATVs were three-wheeled off-
highway models with large balloon tires that existed in the early
1970's. Due to safety concerns, the three-wheeled ATVs were phased-out
in the mid-1980s and replaced by the current and more popular four-
wheeled vehicle known as ``quad runners'' or simply ``quads.'' Quads
resemble the earlier three-wheeled ATVs except that the single front
wheel was replaced with two wheels. The ATV steering system uses
motorcycle handlebars, rather than a steering wheel. The operator sits
on and rides the quad much like a motorcycle. The engines used in quads
tend to be very similar to those used in off-highway motorcycles--
relatively small, single-cylinder two- or four-stroke engines. Quads
are typically divided into utility and sport models. The utility quads
are designed for multi-function use and have the ability to perform
many utility functions, such as plowing snow, tilling gardens, and
mowing lawns in addition to use for recreational riding. They are
typically heavier and equipped with relatively large four-stroke
engines and automatic transmissions with a reverse gear. Sport quads
are smaller and lighter and designed primarily for recreational
purposes. They are equipped with two- or four-stroke engines and manual
transmissions. Presently utility ATVs comprise about 75 percent of the
market and sport models about 25 percent.
Of all of the types of recreational vehicles, ATVs have the largest
number of major manufacturers. All but one of the companies noted above
for off-highway motorcycles and below for snowmobiles are significant
ATV producers. These seven companies represent over 95 percent of total
domestic ATV sales. The remaining 5 percent of sales come from
importers, which tend to import less expensive, youth-oriented ATVs.
As discussed below, we are requiring utility vehicles capable of
speeds above 25 mph to comply the regulations for ATVs.
c. Snowmobiles. Snowmobiles, also referred to as ``sleds,'' are
tracked vehicles designed to operate over snow. Snowmobiles have some
similarities to off-highway motorcycles and ATVs. A snowmobile rider
sits on and rides a snowmobile similar to an ATV. Snowmobiles use high-
powered two- and three-cylinder two-stroke engines that look similar to
off-highway motorcycle engines. Rather than wheels, snowmobiles are
propelled by a track system similar to what is used on a bulldozer. The
snowmobile is steered by two skis at the front of the sled. Snowmobiles
use handlebars similar to off-highway motorcycles and ATVs. The typical
snowmobile seats two riders comfortably. Over the years, snowmobile
performance has steadily increased to the point that many snowmobiles
currently have engines over 100 horsepower and are capable of exceeding
100 miles per hour. The definition for snowmobiles includes a limit of
1.5-meter width to differentiate conventional snowmobiles from ice-
grooming machines and snow coaches, which use very different engines.
There are four major snowmobile manufacturers, accounting for more
than 99 percent of all domestic sales. The remaining sales come from
very small manufacturers who tend to specialize in high-performance
designs.
d. Other recreational vehicles. Currently, our Small SI nonroad
engine regulations cover all recreational engines that are under 19 kW
(25 hp) and have either an installed speed governor or a maximum engine
speed less than 5,000 revolutions per minute (rpm). Recreational
vehicles currently covered by the Small SI standards include go-carts,
golf carts, and small mini-bikes. Although some off-highway
motorcycles, ATVs and snowmobiles have engines with rated horsepower
less than 19 kW, they all have maximum engine speeds greater than 5,000
rpm. Thus they have not been included in the Small SI regulations. The
only other types of small recreational engines not covered by the Small
SI rule are those engines under 19 kW that aren't governed and have
maximum engine speed of at least 5,000 rpm. There are relatively few
such vehicles with recreational engines not covered by the Small SI
regulations. The best example of vehicles that fit in this category are
stand-on scooters and skateboards that have been equipped with very
small gasoline spark-ignition engines. The engines used on these
vehicles are typically the same as those used in string trimmers or
other lawn and garden equipment, which are covered under the Small SI
regulations. Because these engines are generally already covered by the
Small SI regulations and are the same as, or very similar to, engines
as those used in lawn and garden applications, we are revising the
Small SI rules to cover these engines under the Small SI regulations.
To avoid any problems in transitioning to meet emission standards, we
are applying these standards beginning in 2006. We did not receive any
comments on this approach.
2. What Is the Regulatory History for Recreational Vehicles?
The California Air Resources Board (California ARB) established
standards for off-highway motorcycles and ATVs, which took effect in
January 1997 (1999 for vehicles with engines of 90 cc or less).
California has not adopted standards for snowmobiles. The standards,
shown in Table III.A-1, are based on the highway motorcycle chassis
test procedures. Manufacturers may certify ATVs to optional standards,
also shown in Table III.A-1, which are based on the utility engine test
procedure.\38\ This is the test procedure over which Small SI engines
are tested. The stringency level of the standards was based on the
emission performance of small four-stroke engines and advanced two-
stroke engines with a catalytic converter. California ARB anticipated
that the standards would be met initially by using high-performance
four-stroke engines.
---------------------------------------------------------------------------

\38\ 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).

III.A-1--California Off-highway Motorcycle and ATV Standards for Model Year 1997 and later
[1999 and later for engines at or below 90 cc]
----------------------------------------------------------------------------------------------------------------
HC NO_X CO PM
----------------------------------------------------------------------------------------------------------------
Off-highway motorcycle and ATV standards (g/km). \a\ 1.2 .............. 15 ..............
----------------------------------------------------------------------------------------------------------------

[[Page 68262]]

----------------------------------------------------------------------------------------------------------------
HC + NO_X CO PM
--------------------------------------------------------------------------------------------------
Optional standards for ATV engines below 225 cc (g/ \a\ 12.0 300 ..............
bhp-hr)..........................................
Optional standards for ATV engines at or above 225 \a\ 10.0 300 ..............
cc (g/bhp-hr)....................................
----------------------------------------------------------------------------------------------------------------
a Corporate-average standard.

California revisited the program because a lack of certified off-
highway motorcycles from manufacturers was reportedly creating economic
hardship for dealerships. The number of certified off-highway
motorcycle models was particularly inadequate.\39\ In 1998, California
revised the program, allowing the uncertified products in off-highway
vehicle recreation areas with regional/seasonal use restrictions.
Currently, noncomplying vehicles may be 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
with green and red stickers, respectively. Only about one-third of off-
highway motorcycles selling in California are certified. All certified
products have four-stroke engines.
---------------------------------------------------------------------------

\39\ 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, document II-D-08).
---------------------------------------------------------------------------

B. Engines Covered by This Rule

We are adopting new emission standards for new off-highway
motorcycles, ATVs, and snowmobiles. (We are also applying existing
Small SI emission standards to other recreational equipment, as
described above.) The engines used in recreational vehicles tend to be
small, air- or liquid-cooled, reciprocating Otto-cycle engines that
operate on gasoline.\40\ Engines used in vehicle applications
experience engine performance that is characterized by highly transient
operation, with a wide range of engine speed and load capability.
Maximum engine speed are typically well above 5,000 rpm. Also, with the
exception of snowmobiles, the vehicles are typically equipped with
transmissions rather than torque converters to ensure performance under
a variety of operating conditions.\41\
---------------------------------------------------------------------------

\40\ Otto-cycle is another name for a reciprocating, internal-
combustion engine that uses a spark to ignite a homogeneous air and
fuel mixture, in which air-fuel mixing may occur inside or outside
the combustion chamber.
\41\ Snowmobiles use continuously variable transmissions, which
tend to operate like torque converters.
---------------------------------------------------------------------------

1. Two-Stroke vs. Four-Stroke Engines
The engines used by recreational vehicles can be separated into two
distinct designs: two-stroke and four-stroke. The distinction between
two-stroke and four-stroke engines is important for emissions because
two-stroke engines tend to emit much greater amounts of unburned HC and
PM than four-stroke engines of similar size and power. Two-stroke
engines have lower NO_X emissions than do four-stroke engines
because they experience a significant amount of internal exhaust gas
recirculation resulting from exhaust gases being drawn back into the
combustion chamber on the piston's downward stroke while the exhaust
port is uncovered. Exhaust gas is inert and displaces fresh fuel and
air that could otherwise be combusted, which creates lower in-cylinder
temperatures and thus less NO_X. Two-stroke engines also have
greater fuel consumption than four-stroke engines, but they also tend
to have higher power output per-unit displacement, lighter weight, and
better cold-starting performance. These, and other characteristics,
tend to make two-stroke engines popular as a power unit for
recreational vehicles. With the exception of a few youth and touring
models, almost all snowmobiles use two-stroke engines. Currently, about
63 percent of all off-highway motorcycles (predominantly in high-
performance, youth, and entry-level bikes) and 20 percent of all ATVs
sold in the United States use two-stroke engines.
The basis for the differences in engine performance and exhaust
emissions between two-stroke and four-stroke engines can be found in
the fundamental differences in how two-stroke and four-stroke engines
operate. Four-stroke operation takes place in four distinct steps:
intake, compression, power, and exhaust. Each step corresponds to one
up or down stroke of the piston or 180[deg]
of crankshaft rotation. The
first step of the cycle is for an intake valve in the combustion
chamber to open during the intake stroke, allowing a mixture of air and
fuel to be drawn into the cylinder while the piston moves down the
cylinder. The intake valve then closes and the momentum of the
crankshaft causes the piston to move back up the cylinder, compressing
the air and fuel mixture. At the very end of the compression stroke,
the air and fuel mixture is ignited by a spark from a spark plug and
begins to burn. As the air and fuel mixture burns, increasing
temperature and pressure cause the piston to move back down the
cylinder. This is referred to as the ``power'' stroke. At the bottom of
the power stroke, an exhaust valve opens in the combustion chamber and
as the piston moves back up the cylinder, the burnt gases are pushed
out through the exhaust valve to the exhaust manifold, and the cycle is
complete.
In a four-stroke engine, combustion and the resulting power stroke
occur only once every two revolutions of the crankshaft. In a two-
stroke engine, combustion occurs every revolution of the crankshaft.
Two-stroke engines eliminate the intake and exhaust strokes, leaving
only compression and power strokes. This is due to the fact that two-
stroke engines do not use intake and exhaust valves. Instead, they have
intake and exhaust ports in the sides of the cylinder walls. With a
two-stroke engine, as the piston approaches the bottom of the power
stroke, it uncovers exhaust ports in the wall of the cylinder. The high
pressure combustion gases blow into the exhaust manifold. As the piston
gets closer to the bottom of the power stroke, the intake ports are
uncovered, and fresh mixture of air and fuel are forced into the
cylinder while the exhaust ports are still open. Exhaust gas is
``scavenged'' or forced into the exhaust by the pressure of the
incoming charge of fresh air and fuel. In the process, however, some
mixing between the exhaust gas and the fresh charge of air and fuel
takes place, so that some of the fresh charge is also emitted in the
exhaust. Losing part of the fuel out of the exhaust during scavenging
causes very high hydrocarbon emission characteristics of two-stroke
engines. The other major reason for high HC emissions from two-stroke
engines is their tendency to misfire under low-load conditions due to
greater combustion instability.
2. Applicability of Small SI Regulations
In our regulations for Small SI engines, we established criteria,
such as rated engine speed at or above 5,000 rpm and the use of a speed
governor, that excluded engines used in certain types of recreational
vehicles (see 40 CFR 90.1(b)(5)). Engines used in some other types of
recreational vehicles may be covered by the Small SI standards,
depending on the characteristics of the engines. For example,
lawnmower-type

[[Page 68263]]

engines used in go carts are typically covered by the Small SI
standards because they don't operate above 5000 rpm. Similarly, engines
used in golf carts are included in the Small SI program. As discussed
above, we are revising the Small SI regulations to include all
recreational engines except those in off-highway motorcycles, ATVs,
snowmobiles, and hobby engines. Golf cart and go-cart engines will
remain in the Small SI program because the vehicles are not designed
for operation over rough terrain and do not meet the definition of ATV.
We are accordingly removing the 5,000 rpm and speed governor criteria
from the applicability provisions of the Small SI regulations.
3. Utility Vehicles
We proposed to define ATV as a ``nonroad vehicle with three or more
wheels and a seat designed for operation over rough terrain and
intended primarily for transportation'', and that it would include
``both land-based and amphibious vehicles''. We requested comment on
the proposed definition and based on comments, we are modifying the
definition to clearly exclude utility vehicles not capable of reaching
25 mph. Utility vehicles differ from ATVs in several ways. As stated
earlier, an ATV is operated and ridden very similar to a motorcycle,
with the rider straddling the seat and using handlebars to steer the
vehicle. The throttle and brakes are located on the handle bars,
similar to a motorcycle and snowmobile. Utility vehicles look and
operate very similarly to golf carts. The operator sits on a bench seat
with a back support that holds two or more passengers. Rather than
handlebars, utility vehicles use a steering wheel and have throttle and
brake pedals on the floor, similar to an automobile. Utility vehicles
also typically have a cargo box or bed (similar to that found on a
pick-up truck) used for hauling cargo. We define an off-highway utility
vehicle as a ``nonroad vehicle that has four or more wheels, seating
for two or more persons, is designed for operation over rough terrain,
and has either a rear payload of 350 pounds or more or seating for six
or more passengers.'' We are requiring utility vehicles capable of high
speed operation (speeds greater than 25 mph) to meet ATV standards. For
utility vehicles that are permanently governed and not capable of
reaching 25 mph, manufacturers must either continue to certify them to
the Small SI standards (or Large SI standards, if applicable) or
optionally certify them to the new ATV standards.
We received comments from the Outdoor Power Equipment Institute
(OPEI) that the definition should be clarified to exclude utility
vehicles. Most utility vehicles are equipped with engines that are
currently required to meet EPA Small SI standards. OPEI commented that
utility vehicles are designed specifically for work related tasks and
are equipped with seating for passengers, a bed for cargo, and riding-
mower-style controls.
The industry differentiates between utility vehicles based on
vehicle speed. The vast majority of utility vehicles are considered
``low-speed utility vehicles'' (LUVs) and are vehicle speed governed
with maximum speed of less than 25 mph. The engines used in such
vehicles are generally below 25 hp and are typically used in other lawn
and garden or utility applications such as generators or lawn tractors.
The engines differ significantly from those used in recreational
products which are designed for higher rpm operation with an emphasis
on higher performance. OPEI also provided comment on a newer type of
utility vehicle, which uses a more powerful (over 19kW) ATV-based
engine and is capable of speeds of up to 40 mph.
We are finalizing the approach described. The engines used in low-
speed utility vehicles are more similar in design and use to utility
engines than ATVs. The engines used to power these vehicles are often
used in other utility applications, such as lawn and garden tractors
and generators and are typically produced by companies that specialize
in utility and lawn equipment rather than power sport vehicles. These
products are already certified to the Small SI standards.
However, we have some concerns with continuing to use the Small SI
program test cycle for engines used in applications that operate at
broad engine speeds. The cycle was developed primarily for push
lawnmowers and other equipment that operates in a narrow band of engine
speeds. The Small SI test cycle measures emissions only at a single
high engine speed. We are concerned that the Small SI test cycle may
not achieve the same emission reductions for off-highway utility
vehicles in use as it would for lawnmowers, especially as more
stringent standards go into effect. The concern also applies to other
large ride-on equipment in the Small SI program, such as riding lawn
mowers, where engine speed is inherently variable. While the ATV
program may not be appropriate for these low-speed utility applications
due to operating and design differences, the Small SI program as it is
currently designed may not be completely appropriate either. Since we
did not propose changes for the Small SI program which currently
applies to utility vehicles and need to further study the issues, we
are not finalizing such changes to the Small SI program in this Final
Rule. We plan to continue to study the issue and, if necessary, address
it through a future rulemaking for the Small SI program.
In addition to test cycle, there are other reasons we plan to
continue to examine the appropriateness of the Small SI program for
large ride-on equipment. With respect to useful life, we are concerned
that off-highway utility vehicles may be designed to last significantly
longer than the typical lawnmower. 40 CFR 90.105 specifies useful life
values that vary by application with the longest useful life being 1000
hours. It is not clear that this maximum value is high enough to
address the expected life of in-use off-highway utility vehicles,
especially those that are used commercially. Finally, with respect to
the level of the standards, we are concerned about the relative
stringency of the Small SI standards relative to the long-term
standards for ATVs and other nonroad vehicles. Nevertheless, given the
low-speed operation of these vehicles, and other differences, we do not
believe that they should be treated the same as higher speed ATVs. We
did not propose changes for the Small SI program to address the above
issues and need to study them further. However, these vehicles are
unique in many ways, and should be addressed in a future rulemaking.
Given the utility nature of the low-speed vehicles, we believe that
at least for now, it is appropriate to continue to certify them under
40 CFR part 90. For vehicles capable of higher speeds (e.g., greater
than 25 mph), the engine designs and vehicle in-use operation is likely
to be more like ATVs. The test procedures and standards for ATVs will
better fit these high speed vehicles than those in the Small SI
program. For regulatory purposes, we are defining an off-highway
utility vehicle as a nonroad vehicle that has four or more wheels,
seating for two or more persons, is designed for operation over rough
terrain, and has either a rear payload capacity of 350 pounds or more
or total seating for six or more passengers.
4. Hobby Engines
The Small SI rule categorized spark-ignition engines used in model
cars, boats, and airplanes as recreational engines and exempted them
from the

[[Page 68264]]

Small SI program.\42\ We are continuing to exclude hobby engines from
the Small SI program because of significant engine design and use
differences. We also believe that hobby engines are substantially
different than engines used in recreational vehicles and, as proposed,
we are not including spark-ignition hobby engines in this final rule.
We received no comment on our proposed treatment of hobby engines or
any additional information on their design or use.
---------------------------------------------------------------------------

\42\ 80 FR 24292, April 25, 2000.
---------------------------------------------------------------------------

There are about 8,000 spark-ignition engines sold per year for use
in scale-model aircraft, cars, and boats.\43\ This is a very small
subsection of the overall model engine market, most of which are glow-
plug engines that run on a mix of castor oil, methyl alcohol, and nitro
methane.\44\ A typical spark-ignition hobby engine is approximately 25
cc with a horsepower rating of about 1-3 hp, though larger engines are
available. These spark-ignition engines are specialty products sold in
very low volumes, usually not more than a few hundred units per engine
line annually. Many of the engines are used in model airplanes, but
they are also used in other types of models such as cars and boats.
These engines, especially the larger displacement models, are
frequently used in competitive events by experienced operators. The
racing engines sometimes run on methanol instead of gasoline. In
addition, the engines are usually installed and adjusted by the
hobbyist who selects an engine that best fits the particular model
being constructed.
---------------------------------------------------------------------------

\43\ Comments submitted by Hobbico on behalf of Great Plains
Model Distributors and Radio Control Hobby Trade Association,
February 5, 2001, Docket A-2000-01, document II-D-58.
\44\ Hobby engines with glow plugs are considered compression-
ignition (diesel) engines because they lack a spark-ignition system
and a throttle (see the definition of compression-ignition, 40 CFR
89.2). The nonroad diesel engine regulations 40 CFR part 89
generally do not apply to hobby engines, so these engines are
unregulated.
---------------------------------------------------------------------------

The average annual hours of operation has been estimated to be
about 12.2 hours per year.\45\ The usage rate is very low compared to
other recreational or utility engine applications due to the nature of
their use. Much of the hobby revolves around building the model and
preparing the model for operation. The engine and model must be
adjusted, maintained, and repaired between uses.
---------------------------------------------------------------------------

\45\ Comments submitted by Hobbico on behalf of Great Plains
Model Distributors and Radio Control Hobby Trade Association,
February 5, 2001, Docket A-2000-01, document II-D-58.
---------------------------------------------------------------------------

Spark-ignition model engines are highly specialized and differ
significantly in design compared to engines used in other recreational
or utility engine applications. While some of the basic components such
as pistons may be similar, the materials, airflow, cooling, and fuel
delivery systems are considerably different.46 47 Some
spark-ignition model engines are scale replicas of multi-cylinder
aircraft or automobile engines and are fundamentally different than
spark-ignition engines used in other applications. Model-engine
manufacturers often select lighter-weight materials and simplified
designs to keep engine weight down, often at the expense of engine
longevity. Hobby engines use special ignition systems designed
specifically for the application to be lighter than those used in other
applications. To save weight, hobby engines typically lack pull
starters that are found on other engines. Hobby engines must be started
by spinning the propeller. In addition, the models themselves vary
significantly in their design, introducing packaging issues for engine
manufacturers.
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\46\ E-mail from Carl Maroney of the Academy of Model
Aeronautics to Christopher Lieske, of EPA, June 4, 2001, Docket A-
2000-01, document II-G-144.
\47\ Comments submitted by Hobbico on Behalf of Great Plains
Model Distributors and Radio Control Hobby Trade Association,
February 5, 2001, Docket A-2000-01, document II-D-58.
---------------------------------------------------------------------------

We are not including spark-ignition hobby engines in the
recreational vehicles program. The engines differ significantly from
other recreational engines in their design and use, as noted above.
Emission-control strategies envisioned for other recreational vehicles
may not be well suited for hobby engines because of their design,
weight constraints, and packaging limitations. Approaches such as using
a four-stroke engine, a catalyst, or fuel injection all would involve
increases in weight, which would be particularly problematic for model
airplanes. The feasibility of these approaches for these engines is
questionable. Reducing emissions, even if feasible, would likely
involve fundamental engine redesign and substantial R&D efforts. The
costs of achieving emission reductions are likely to be much higher per
engine than for other recreational applications because the R&D costs
would be spread over very low sales volumes. The cost of fundamentally
redesigning the engines could double the cost of some engines.
By contrast, because of their very low sales volumes, annual usage
rates, and relatively short engine life cycle, spark-ignition hobby
engine emission contributions are extremely small compared to
recreational vehicles. The emission reductions possible from regulating
such engines would be minuscule (we estimate that spark-ignition hobby
engines as a whole account for less than 30 tons of HC nationally per
year, much less than 0.01 percent of mobile source HC emissions).\48\
---------------------------------------------------------------------------

\48\ For further information on the feasibility, emission
inventories, and costs, see ``Analysis of Spark Ignition Hobby
Engines'', Memorandum from Chris Lieske to Docket A-2000-01,
document II-G-144.
---------------------------------------------------------------------------

In addition, hobby engines differ significantly in their in-use
operating characteristics compared to small utility engines and other
recreational vehicle engines. It is unclear if the test procedures
developed and used for other types of spark-ignition engine
applications would be sufficiently representative or even technically
practical for hobby engines. We are not aware of any efforts to develop
an emission test cycle or conduct any emission testing of these
engines. Also, because installing, optimizing, maintaining, and
repairing the engines are as much a part of the hobby as operating the
engine, emission standards could fundamentally alter the hobby itself.
Engines with emission-control systems would be more complex and the
operator would need to be careful not to make changes that would cause
the engine to exceed emission standards. EPA will continue to review
these issues, as necessary, in the future and reconsider adoption of
regulations if appropriate.
5. Competition Exemptions
a. Off-Highway motorcycles. Currently, a large portion of off-
highway motorcycles are designed as competition/racing motorcycles.
These models often represent a manufacturer's high-performance
offerings in the off-highway market. Most such motorcycles are of the
motocross variety, although some high-performance enduro models are
marketed for competition use.49 50 These high-performance
motorcycles are

[[Page 68265]]

largely powered by two-stroke engines, though some four-stroke models
have been introduced in recent years.
---------------------------------------------------------------------------

\49\ A motocross bike is typically a high-performance off-
highway motorcycle that is designed to be operated in motocross
competition. Motocross competition is defined as a circuit race
around an off-highway closed-course. The course contains numerous
jumps, hills, flat sections, and bermed or banked turns. The course
surface usually consists of dirt, gravel, sand, and mud. Motocross
bikes are designed to be very light for quick handling and easy
maneuverability. They also come with large knobby tires for
traction, high fenders to protect the rider from flying dirt and
rocks, aggressive suspension systems that allow the bike to absorb
large amounts of shock, and are powered by high-performance engines.
They are not equipped with lights.
\50\ An enduro bike is very similar in design and appearance to
a motocross bike. The primary difference is that enduros are
equipped with lights and have slightly different engine performance
that is more geared towards a broader variety of operation than a
motocross bike. An enduro bike needs to be able to cruise at high
speeds as well as operate through tight woods or deep mud.
---------------------------------------------------------------------------

Competition events for motocross motorcycles mostly involve closed-
course or track racing. Other types of off-highway motorcycles, such as
enduros and trials bikes, are usually marketed for trail or open-area
use. When used for competition, these models are likely to be involved
in point-to-point competition events over trails or stretches of open
land. There are also specialized off-highway motorcycles that are
designed for competitions such as ice racing, drag racing, and observed
trials competition. A few races involve professional manufacturer-
sponsored racing teams. Amateur competition events for off-highway
motorcycles are also held frequently in many areas of the U.S.
Clean Air Act subsections 216 (10) and (11) exclude engines and
vehicles ``used solely for competition'' from nonroad engine and
nonroad vehicle regulations. In the proposal we stated that in previous
nonroad engine emission-control programs, we have generally defined the
term as follows:
Used solely for competition means exhibiting features that are not
easily removed and that would render its use other than in competition
unsafe, impractical, or highly unlikely.
Most motorcycles marketed for competition do not appear to have
obvious physical characteristics that constrain their use solely to
competition. In fact, they are usually sold by dealers from the
showroom floor. Upon closer inspection, however, there are several
features and characteristics for many competition motorcycles that make
recreational use unlikely. For example, motocross bikes are not
equipped with lights or a spark arrester, which prohibits them from
legally operating on public lands (such as roads, parks, state land,
and federal land).\51\ Vehicle performance of modern motocross bikes is
so advanced (for example, with extremely high power-to-weight ratios
and advanced suspension systems) that it is highly unlikely that these
machines will be used for recreational purposes. In addition, motocross
and other competition off-highway motorcycles typically do not come
with a warranty, which further deters purchasing and using competition
bikes for recreational operation.\52\ We believe these features are
sufficient in distinguishing competition motorcycles from recreational
motorcycles. Therefore, we are specifically adopting the following
features as indicative of motorcycles used solely for competition:
absence of a headlight or other lights; the absence of a spark
arrester; suspension travel greater than 10 inches; an engine
displacement greater than 50 cc; absence of a manufacturer warranty;
and the absence of a functional seat.
---------------------------------------------------------------------------

\51\ A spark arrester is a device located in the end of the
tailpipe that catches carbon sparks coming from the engine before
they get out of the exhaust system. This is important when a bike is
used off-highway, where hot carbon sparks falling in grassy or
wooded areas could result in fires.
\52\ Most manufacturers of motocross racing motorcycles do not
offer a warranty. Some manufacturers do, however, offer very limited
(1 to 3 months) warranties under special conditions.
---------------------------------------------------------------------------

Manufacturers must specifically request and receive an exemption
from EPA to sell off-highway motorcycles without a certificate under
the competition exemption. Vehicles not meeting the applicable criteria
listed above will be exempted only in cases where the manufacturer has
clear and convincing evidence that the vehicles for which the exemption
is being sought will be used solely for competition. Examples of this
type of evidence may be technical rationale explaining the differences
between a competition and non-competition motorcycle, marketing and
sales information indicating the intent of the motorcycle for
competition purposes, and survey data from users indicating the
competitive nature of the motorcycle.
Although there are several features that generally distinguish
competition motorcycles from recreational motorcycles, several parties
have commented that they believe motorcycles designed for competition
use are also used for recreational purposes, rather than solely for
competition. This is of particular concern because competition
motorcycles represent about 29 percent of total off-highway motorcycle
sales or approximately 43,000 units per year. However, a study on the
characterization of off-highway motorcycle usage found that there are
numerous--and increasingly popular--amateur off-highway motorcycle
competitions across the country, especially motocross.\53\ The
estimated number of off-highway motorcycle competitors is as high as
80,000. Since it is very common for competitive riders to replace their
machines every one to two years, the sale of 43,000 off-highway
competition motorcycles appears to be a reasonable number, considering
the number of competitive participants. We are therefore confident
that, although we are excluding a high percentage of off-highway
motorcycles as being competition machines, the criteria laid out above
are indicative of motorcycles used solely for competition.
---------------------------------------------------------------------------

\53\ ``Characterization of Off-Road Motorcycle Use,'' ICF
Consulting, September 2001, A-2000-1 document II-A-81.
---------------------------------------------------------------------------

However, we do recognize that it is possible that some competition
motorcycles will be used for recreational purposes. We are therefore
adopting a provision within the regulations that allows the Agency to
deny a manufacturer's claim for exemption from the standards for any
models, including models that meet the six specified criteria, where
other information is available that indicates these off-highway
motorcycle models are not used solely for competition. This same
provision allows the Agency to deny claims for exemptions in later
years even if they had been granted previously. Examples of this type
of information can be state registration data that indicate a
significant number of competition exempt models being registered to
operate on public lands. Off-highway competition motorcycles designed
for motocross competition are not typically required to be registered
with states, since most motocross competitions occur on closed-circuit
courses on private, not public land, and motocross machines lack spark
arresters which are required to operate on public land. We believe the
possibility of losing an exemption for competition motorcycles will
encourage manufacturers to take proper actions in promoting, marketing,
and guaranteeing that competition machines are sold to those
individuals who will use them solely for competition.
b. Snowmobiles and ATVs. Snowmobiles and ATVs are also used in
competition events; however, the percentage of snowmobiles or ATVs used
solely for competition is not nearly as large as that for off-highway
motorcycles. Since snowmobile and ATV competition have typically not
been as popular as off-highway motorcycle competitions, there has not
been the demand for competition machines that exists with off-highway
motorcycles. As a result, manufacturers have not manufactured and sold
directly from their dealers competition snowmobiles and ATVs like they
have off-highway motorcycles. Most snowmobiles and ATVs used in
competition events are modified recreational vehicles, rather than
stock racing machines bought directly from the dealer, as is the case
with off-highway motorcycles. As a result, there isn't the same concern
over potential misuse of competition snowmobiles and ATVs for
recreational purposes.

[[Page 68266]]

Competition snowmobiles and ATVs aren't currently sold directly at
the dealership. Therefore, manufacturers can receive a competition
exemption from EPA for snowmobiles and ATVs meeting all of the
following criteria: the vehicle or engine may not be displayed for sale
in any public dealership; sale of the vehicle must be limited to
professional racers or other qualified racers; and the vehicle must
have performance characteristics that are substantially superior to
noncompetitive models.
As with off-highway motorcycles, snowmobiles and ATVs not meeting
the applicable criteria listed above will be exempted only in cases
where the manufacturer has clear and convincing evidence that the
vehicles for which the exemption is being sought will be used solely
for competition. We are also adopting the same provision as for off-
highway motorcycles within the regulations that allows the Agency to
deny a manufacturer's claim for exemption from the standards for any
models where other information is available that indicates these
snowmobiles and ATVs models are not used solely for competition. As
with off-highway motorcycles, this same provision allows the Agency to
deny claims for exemptions in later years even if they had been granted
previously.

C. Emission Standards

1. What Are the Emission Standards and Compliance Dates?
a. Off-highway motorcycles. We are adopting HC plus NO_X
and CO standards for off-highway motorcycles. We expect the largest
benefit to come from reducing HC emissions from two-stroke engines.
Two-stroke engines have very high HC emission levels. Baseline
NO_X levels are relatively low for engines used in these
applications and therefore including NO_X in the standard
serves only to cap NO_X emissions for these engines.
Comparable CO reductions can be expected from both two-stroke and four-
stroke engines, as CO levels are similar for the two engine types. We
are also adopting averaging, banking and trading provisions for off-
highway motorcycles, as discussed below.
In the current off-highway motorcycle market, consumers can choose
between two-stroke and four-stroke models in most sizes. Each engine
type offers unique performance characteristics. Some manufacturers
specialize in two-stroke or four-stroke models, while others offer a
mix of models. The HC standard is likely to be a primary determining
factor for what technology manufacturers choose to employ to meet
emission standards overall. HC emissions can be reduced substantially
by switching from two-stroke to four-stroke engines. Four-stroke
engines are very common in off-highway motorcycle applications.
Approximately 55 percent of non-competition off-highway motorcycles are
four-stroke. Certification results from California ARB's emission-
control program for off-highway motorcycles, combined with our own
baseline emission testing, provides ample data on the emission-control
capability of four-stroke engines in off-highway motorcycles. Off-
highway motorcycles certified to California ARB standards for the 2000
model year have HC certification levels ranging from 0.4 to 1.0 g/km.
These motorcycles have engines ranging in size from 48 to 650 cc; none
of these use catalysts.
The emission standards for off-highway motorcycles take effect
beginning in the 2006 model year. We will allow a phase-in of 50-
percent implementation in the 2006 model year with full implementation
in 2007. These standards apply to testing with the highway motorcycle
Federal Test Procedure (FTP) test cycle. For HC+NO_X
emissions, the standard is 2.0 g/km (3.2 g/mi). For CO emissions, the
standard is 25.0 g/km (40.5 g/mi). Both of these standards are based on
averaging with a cap on the Family Emission Limit (FEL) of 20 g/km for
HC+NO_X and 50 g/km for CO. Banking and trading provisions
are also included in the program, as described in Section III.C.2.
These emission standards allow us to set near-term requirements to
introduce the low-emission technologies for substantial emission
reductions with minimal lead time. We expect manufacturers to meet
these standards using four-stroke engines with some low-level
modifications to fuel-system calibrations. These systems are similar to
those used for many years in highway motorcycle applications, but with
less overall sophistication for off-highway applications.
We received comments from several states and environmental groups
encouraging us to harmonize our off-highway motorcycle standards with
California. The comments focused on the perceived difference in
stringency between the two programs. For California, the standard is an
HC-only standard of 1.2 g/km. Our standard is a HC+NO_X
standard of 2.0 g/km. We believe it is prudent to set a
HC+NO_X standard in lieu of a HC-only standard since the main
emission-control strategy is expected to be the use of four-stroke
engines in lieu of two-stroke engines. Two-stroke engines emit
extremely low levels of NO_X. Four-stroke engines, on the
other hand, have higher NO_X emission levels, in the range of
0.3 g/km on average. This is part of the reason why we proposed a
somewhat higher numeric standard compared to California.
The California standards, which were adopted in 1994, were
stringent enough that manufacturers were unable to certify several
models of off-highway motorcycles, even some with four-stroke engine
technology. The result was a substantial shortage of products for
dealers to sell in California. The shortage led California to change
their program to allow manufacturers to sell noncompliant off-highway
motorcycles under some circumstances. As a result, approximately a
third of the off-highway motorcycles sold in California are compliant
with the standards. The uncertified models being sold in California
include both two-stroke and four-stroke machines.
EPA received comments from dealers and consumers concerned that a
similar shortage could arise nationwide if EPA adopted the California
standards. EPA shared this concern and proposed standards that were
somewhat less stringent than that of California, based on test data
from high-performance four-stroke machines. We are finalizing this
approach to ensure the four-stroke technology can be implemented
broadly across the product line in the 2006 time-frame. Although the
approach we are finalizing contains somewhat less stringent standards
than the California program, we believe it will achieve reductions
beyond that of the California program because more products will be
certified (even when the competition exemption is taken into account).
The vast majority of the HC reductions achieved by the program come
from shifting away from conventional two-stroke engines which have HC
emissions levels in the range of 35 g/km. The 2.0 g/km standard
represents about a 95-percent reduction in emissions for these
vehicles.
If we were to go beyond this level of reduction, manufacturers
would need to employ on a widespread basis additional technology that
presents significant technical issues concerning their application to
off-highway motorcycles given their extreme usage patterns and issues
such as safety, packaging, and weight. For example, technologies such
as electronic fuel injection and secondary air injection raise concerns
about their durability and reliability in the harsh operating
environments to which off-highway motorcycles are sometimes exposed.

[[Page 68267]]

The use of catalytic converters poses concerns over packaging,
durability and safety. Off-highway motorcycles are very light and
narrow. These attributes are necessary for operating through tight
forest trails and other harsh conditions. This leaves little room for
packaging a catalyst so that it won't be damaged from engine vibration,
shock resulting from jumps and hopping logs, and falling over and
hitting objects, such as trees and rocks. These technologies may become
compatible for off-highway motorcycles in the future, but we do not
believe that it is appropriate to promulgate emission standards based
on these technologies at this time, given the technical problems
currently associated with their use. Four-stroke engine technology has
advanced considerably since the California regulations went into
effect. Manufacturers are now capable of offering four-stroke engines
that provide excellent performance. This performance can be achieved
only as long as manufacturers are allowed to operate four-stroke
engines with a slightly rich air and fuel mixture, which can result in
somewhat higher HC and CO emissions. Although the standards we are
setting are higher than those in California, we believe they will
require four-stroke engines that are well calibrated for emissions
control without significantly sacrificing performance. For these
reasons, we believe the standards we are establishing are appropriate.
As discussed above in Section III.B.5, the Clean Air Act requires
us to exempt from emission standards off-highway motorcycles used for
competition. We expect several competition two-stroke off-highway
motorcycle models to continue to be available. We are concerned that
setting standards as stringent as California's would result in a
performance penalty for some four-stroke engines that would be
unacceptable to the consumers. This could encourage consumers who want
performance-oriented off-highway motorcycles to purchase competition
vehicles (and use them recreationally) in lieu of purchasing compliant
machines that don't provide the desired performance. We believe that
our emission standards will allow the continued advancement of four-
stroke technology and properly considers available emission-control
technology while taking vehicle performance into consideration and
avoiding significant adverse impacts on performance.
As proposed, we are also finalizing an option allowing off-highway
motorcycles with an engine displacement of 50 cc or less to be
certified using the Small SI emission standards for non-handheld Class
I engines. These youth-oriented models may not be able to operate over
the FTP due to the higher speeds of the test cycle. We did not receive
comment on this provision.
Optional Standards
During the comment period, we received several comments expressing
concern that our proposed standard of 2.0 g/km HC+NO_X for
off-highway motorcycles would effectively prohibit the use of two-
stroke engines in non-competition applications. These engines currently
have typical HC+NO_X levels of about 35 g/km. The commenters
argued that two-stroke engines possess several unique attributes, such
as high power and light weight, that make two-stroke powered off-
highway motorcycles more desirable to some operators, especially
smaller, lighter riders, than heavier four-stroke powered off-highway
motorcycles.
We also received comments from several states and environmental
organizations expressing strong concern over the number of competition
off-highway motorcycles that would be exempt from our regulations as a
result of our competition exemption. They felt that people purchasing
exempt competition motorcycles would use them for recreational purposes
instead of solely for competition.
One manufacturer indicated that they were planning on building
high-performance off-highway motorcycles equipped with direct fuel-
injection two-stroke engines that would potentially be capable of
meeting a HC+NO_X standard of 4.0 g/km. To enable use of this
technology, they suggested that we should adopt a standard of 4.0 g/km
instead of the proposed standard of 2.0 g/km. The commenter believes
that direct injection could be used to make clean competition machines
and also argued that the technology is robust and not as susceptible to
user modifications as other technologies such as catalysts. The
commenter wanted an opportunity to develop and certify their product
because it perceives a benefit to the purchaser not only in performance
but also in the ability for the owner to resell the competition vehicle
into the secondary market without concerns about potential misuse. In
addition, the owner would be able to use the vehicle both for
competition and recreation.
It is clear that if manufacturers were able to certify and bring to
market clean competition machines as described by the commenter,
significant reductions in emissions would be gained over conventional
two-stroke technology. Some competition models we tested had baseline
HC and CO emissions in excess of 50 g/km and 40 g/km, respectively. We
believe it is appropriate to provide an avenue for the development and
voluntary certification of clean competition motorcycles. Therefore, we
are finalizing an optional set of standards for off-highway motorcycles
of 4.0 g/km HC+NO_X and 35.0 g/km CO. For manufacturers to
utilize this option, however, they must certify all of their models,
including their competition models, to the optional standards. To
qualify for this option, a manufacturer must show that ten percent or
more of their sales would otherwise meet the competition definition.
The optional standard was derived from the fact that non-
competition four-stroke engines can meet a 2.0 g/km level and
competition two-stroke machines with advanced direct fuel-injection
technology could meet a 8.0 g/km level. Since approximately one-third
of the total off-highway motorcycle fleet are competition machines and
the other two-thirds would be non-competition four-stroke recreational
machines, the weighting of the 2.0 g/km level by two-thirds and the 8.0
g/km level by one-third results in a weighted standard of 4.0 g/km.
This presumes that emissions from four-stroke engines will not increase
under this option and that non-competition engines will be almost
exclusively four-stroke engines. These assumptions are discussed below.
The significant reductions in otherwise unregulated competition engines
means that this option should produce even greater overall reductions
than the base 2.0 g/km standard. We recognize that for some
manufacturers this program will increase opportunities to make a
limited number of non-competition recreational two-stroke machines;
however, we believe that the number of two-stroke non-competition
engines developed under this program will be limited by the fact that
the required technology (direct fuel-injection) would be too expensive
and complex for the recreational motorcycle market. The majority of
non-competition recreational off-highway motorcycles that use two-
stroke engines are entry-level and youth motorcycles, where cost and
simplicity are important factors. There is also the fact that for every
two stroke non-competition engine manufactured under this program, a
manufacturer must make one less competition engine or must make more
four-stroke engines. Further, we believe that any increase in the
number of non-competition two-stroke engines is justified given the
fact that this program will overall bring levels from off-highway
engines down

[[Page 68268]]

considerably and the fact that the technology needed to reduce
emissions from competition machines will only be made available and
used if, under this optional approach, manufacturers have an incentive
to use the technologies.
One major incentive in using this approach is the fact that once
these machines are certified, a consumer will be able to use these
machines legally for non-competition uses, which increases the value of
the competition machines. This approach thus will also reduce the
incentive for manufacturers to manufacturer all of their two-stroke
machines as competition machines to avoid regulation, and thus reduce
the incentive for users to circumvent the regulations. This may mean
that any increase in two-stroke non-competition engines under this
approach would not lead to an increase in total two-stroke sales,
because manufacturers will not have an incentive to increase the number
of two-stroke competition vehicles to avoid regulation.
We believe this approach is responsive to all of the above
comments. It directly addresses the concerns of the manufacturer
developing the new competition motorcycle and also helps address the
concerns of users, states, and environmental groups. The successful
development and certification of clean competition models increases the
choices for consumers in the marketplace. Offered the option of a
certified high-performance two-stroke off-highway motorcycle that can
be used both for competition and recreation, consumers may not feel the
need to purchase exempt competition motorcycles. This option has the
potential to significantly decrease the number of conventional two-
stroke competition machines sold under the competition exemption and is
likely to decrease the potential for misuse of competition machines.
Conventional competition two-stroke motorcycles generate extremely high
levels of HC emissions, as noted above. For every conventional two-
stroke competition machine replaced by a certified competition machine,
HC emissions would be reduced by 80 percent, or more.
While the 4.0 g/km standard is higher than the 2.0 g/km standard
contained in the base program, we do not expect any loss in emissions
reductions from four-stroke models. We continue to believe most off-
highway motorcycles will continue to be powered by four-stroke engines.
Most non-competition off-highway motorcycles are already four-stroke
motorcycles, and the trend towards four-stroke is continuing even in
the absence of these regulations. We are convinced that there will be
no backsliding of emissions control for motorcycles using four-stroke
engines, because the dirtiest of the four-stroke models tend to be
competition machines, and our emissions testing indicates that
competition four-stroke off-highway motorcycles have HC+NO_X
emission levels below 2.0 g/km. Since these motorcycles are optimized
for power and racing conditions, there is no incentive for
manufacturers to increase HC+NO_X emissions from their
current levels. In fact, increasing the emission levels would mean
increasing the air-to-fuel mixture, which would tend to reduce the
engines performance.
As with the primary program, these optional standards would take
effect in 2006 with 50-percent implementation and full implementation
in 2007 and manufacturers could switch between the options from model
year to model year. The HC+NO_X standard can be met through
averaging with some families certified above the standards and some
below. If averaging is used, the FEL cap would be 8.0 g/km.
We are retaining the averaging approach for this option because it
may be a critical flexibility for manufacturers pursuing clean
competition products. The commenter based its recommendation for a 4.0
g/km standard on their projections for a single prototype model
equipped with a medium sized engine. This engine is in the early stages
of development and there is some uncertainty as to what emissions level
the final product can achieve. Also, manufacturers may want to apply
their approach to other engines that may not be able to achieve this
same level of control. Manufacturers could find that they can produce
competition products that are very clean relative to the baseline but
with higher emissions than 4.0 g/km. For example, larger engine sizes
could have emissions levels somewhat higher than the 4.0 g/km suggested
by the commenter. We are not satisfied at this time that two-stroke
off-highway motorcycles, particularly those used in competition could
meet the 4.0 g/km standard, especially considering the special
performance needs of competition motorcycles. Therefore, rather than
keeping a 2.0 g/km standard for four-stroke engines and having a
standard higher than 4.0 g/km for two-stroke engines (a standard as
high as 8.0 g/km might be appropriate), we are using a 4.0 g/km
standard that permits averaging. Averaging provides flexibility for
manufacturers to bring cleaner two-stroke, particularly cleaner
competition two-stroke, engines to market without creating a
disincentive to building four-stroke engines. One way of taking
advantage of the averaging program in this way would be for a
manufacturer to maximize its sales of four-stroke models as part of its
sales mix, and average the emissions from these engines against the
higher emissions of the two-stroke competition engines which still
would need to be much cleaner than if they were unregulated. This
approach therefore requires the substantial use of cleaner four-stroke
technologies while at the same time encouraging manufacturers to
substantially reduce emissions from motorcycles that would otherwise be
unregulated competition motorcycles. We have capped the emissions
levels at 8.0 g/km HC+NO_X because we want to ensure that
products certified under this option provide large emissions reductions
compared to baseline levels and that the option provides environmental
benefits in all cases. Competition motorcycles certified to the 8.0 g/
km level would continue to provide over a 75-percent reduction in HC
emissions over baseline levels.
One of the challenges facing manufacturers selecting this option is
the potentially high CO emissions from competition machines. We tested
competition models and found CO emissions to be in the range 25 to 50
g/km. Although this option contains a somewhat higher CO standard (35
g/km compared to 25 g/km) than the base program, manufacturers are
still expected to need to control CO emissions through tight engine
calibrations. We are not including averaging for the less stringent CO
standard. As noted by the manufacturer supporting the 4.0 g/km option,
direct injection technology is likely to reduce CO from two-stroke
engines. We believe that through proper calibration, the 35 g/km
standard will be achievable and will not significantly impede
manufacturers in selecting this option.
b. ATVs. We are adopting HC plus NO_X and CO standards
for ATVs. We expect the largest benefit to come from reducing HC
emissions from two-stroke engines. Two-stroke engines have very high HC
emission levels. Baseline NO_X levels are relatively low for
engines used in these applications and therefore including
NO_X in these standards serves only to cap NO_X
emissions for these engines. Comparable CO reductions can be expected
from both two-stroke and four-stroke engines, as CO levels are similar
for the two engine types. We are also adopting averaging, banking and
trading provisions for ATVs, as discussed below.
In the current ATV market, consumers can choose between two-stroke
and four-stroke models, although the

[[Page 68269]]

majority, approximately eighty-percent of sales, are four-stroke. Each
engine type offers unique performance characteristics. Some
manufacturers specialize in two-stroke or four-stroke models, but most
manufacturers offer a mix of models. The HC standard is likely to be a
primary determining factor for which technology manufacturers choose to
employ to meet emission standards overall. HC emissions can be reduced
substantially by switching from two-stroke to four-stroke engines.
Certification results from California ARB's emission-control program
for ATVs, combined with our own baseline emission testing, provides
ample data on the emission-control capability of four-stroke engines in
ATVs.
In the proposal we included two phases of ATV standards. The first
phase of standards, 2.0 g/km HC+NO_X and 25 g/km CO, was
proposed to be phased in at 50 percent of production in 2006 with the
remainder phased-in for 2007. We proposed a second set of standards
that included a more stringent 1.0 g/km HC+NO_X standard with
no change to the CO standards. It was to be met in 2009/2010 using the
same 50-percent and 100-percent phase-in scheme as Phase 1. We proposed
that both phases of HC+NO_X standards could be met through
averaging.
We received comments from several environmental groups stating that
we should harmonize our Phase 1 standards with the California FTP-based
standards. Manufacturers did not comment on the level of our proposed
Phase 1 HC+NO_X standards. However, in a letter sent to the
Agency in August 6, 2001, just before we published the proposal, the
Motorcycle Industry Council stated that the most cost-effective
approach to setting standards for ATVs would be to adopt the California
HC standards of 1.2 g/km. They did comment on the fact that almost all
of the CO nonattainment areas identified in the Draft Regulatory
Support Document are now in compliance and that ATV activity is
typically so far removed from congested urban areas, that we should
delete the proposed CO standard.\54\ Manufacturers stated generally
that CO standards will make it more difficult to meet the
HC+NO_X standards but did not provide additional specific
comments on the feasibility or costs of the CO level proposed. In
subsequent meetings with manufacturers, they suggested that if we were
not going to delete the CO standard, it should be set sufficiently high
so that it would not be an impediment to meeting the HC+NO_X
standard. They suggested a level of 50.0 g/km.
---------------------------------------------------------------------------

\54\ We respond to these comments in Section II of the Summary
and Analysis of Comments.
---------------------------------------------------------------------------

We have decided to finalize only one set of HC+NO_X
emission standards for the 2006 model year that are essentially
equivalent to the California standard. The emission standards for ATVs
take effect beginning in the 2006 model year. We will allow a phase-in
of 50-percent implementation in the 2006 model year with full
implementation in 2007. These standards apply to testing with the
highway motorcycle Class I FTP test cycle. For HC+NO_X
emissions, the standard is 1.5 g/km (2.4 g/mi). The California program
has a HC-only standard of 1.2 g/km. We have made the standard 1.5 g/km
to account for NO_X emissions. For CO emissions, we agree
with manufacturers that CO standards can make it more difficult to meet
the HC+NO_X standard. Based on our emission test data, we
feel that a standard of 35.0 g/km (56.4 g/mi) is more appropriate than
the 25.0 g/km standard we proposed or the 50.0 g/km standard suggested
by the manufacturers. A standard of 35.0 g/km will still result in an
overall reduction in CO emissions from high emitting ATVs, but will
also allow manufacturers to balance CO control with the need to meet
stringent NO_X levels. The HC+NO_X standard may be
met through averaging. Banking and trading provisions for
HC+NO_X are also being included in the program, as discussed
in C.2., below.
Our decision to finalize a 1.5 g/km value rather than the 2.0 g/km
value is consistent with the manufacturers technical capability in the
2006/2007 time-frame. The 1.5 g/km HC+NO_X and 35 g/km CO
standards require the use of engine technology changes and add-on
devices such as secondary air systems, which are clearly available for
ATV application in this time frame. We proposed a 1.0 g/km
HC+NO_X standard for a 2009/2010 phase-in which could require
use of catalytic converter technology in many models of ATVs. As
discussed below, we are not finalizing that proposal now, and thus find
it appropriate to finalize more stringent Phase 1 standards which are
technologically feasible and otherwise consistent with statutory
criteria related to cost, safety, noise, and energy considerations.
Aligning our emission standards with those currently in place in
California allows us to set requirements to introduce the low-emission
technologies for substantial emission reductions with reasonable lead
time and will for the most part allow manufacturers to sell one model
in all fifty states. This ``harmonization'' between federal and
California requirements is valued by industry because it allows the
development and production of one emission-control technology per
model/family. However, in a few cases, we expect emissions reductions
under the EPA program that go beyond that of the California program
because California allows the sale of uncertified ATVs, including two-
stroke models, under their red sticker provisions. With the exception
of competition exempt ATVs, all ATV models subject to the EPA program
will need to be certified. We expect manufacturers to meet these
standards using four-stroke engines with some modifications to fuel-
system calibrations and some limited use of secondary air systems.
These systems are similar to those used for many years in highway
applications, but will likely require lesser sophistication than used
in highway motorcycle applications.
In addition to being consistent with the California standards, we
feel the 1.5 g/km HC+NO_X standard is more appropriate than
the proposed 2.0 g/km standard because our testing has shown that
emission levels from four-stroke ATVs can vary considerably. We stated
in the proposed rule that a standard of 2.0 g/km HC+NO_X
would be a four-stroke enforcing standard, which would most likely
result in the elimination of any two-stroke engines, but not
necessarily require any additional control from the four-stroke
engines. As stated above, a standard of 1.5 g/km HC+NO_X will
require the use of engine technology changes and add-on devices such as
secondary air systems, which are clearly available for ATV application
in this time frame.
At this point, we do not believe it is appropriate to promulgate
Phase 2 standards. In the proposal, we projected significant use of
secondary air systems and catalysts for meeting the Phase 2 standards.
Since that time, we have been conducting testing on ATVs with the type
of catalysts and secondary air systems we envisioned for the Phase 2
standards to demonstrate feasibility. However, the testing we have done
to date has not been sufficient to reach an affirmative conclusion on
the feasibility of the Phase 2 standards. Testing with secondary air
systems and catalysts have not shown consistent results and we have had
only partial success in demonstrating the feasibility of the proposed
Phase 2 standards using these technologies. In testing on a utility-
type ATV, these technologies have provided only small emissions
reductions.\55\ The

[[Page 68270]]

results of our preliminary testing are discussed further in Section
III.F and in the Final Regulatory Support Document. It is unclear if
the level of technology we projected in the proposal would be
sufficient to meet the Phase 2 standards. We have not done enough
research or testing on other potential technologies, such as electronic
or direct fuel injection, to finalize a decision based on these
technologies. We plan to continue to evaluate the technologies that
would be needed to meet the Phase 2 levels and determine if those
levels can be met with the level of technology we projected in the
proposal or with other technology. We also received comments that we
underestimated costs for Phase 2 and we will continue to evaluate costs
as well.
---------------------------------------------------------------------------

\55\ Utility-type ATVs, it should be noted, are not the same as
utility vehicles. Utility vehicles are not considered ATVs due to
fundamental differences in the vehicle characteristics. Most utility
vehicles are currently regulated by the Small SI program, with a
small subset of utility vehicles required by the Final Rule to meet
ATV standards. See section III.B.3. above, for a complete discussion
of utility vehicles. When we say utility-type ATV, we are referring
to ATVs that have features that are work related such as cargo
racks. These ATVs are often somewhat larger and bulkier than sport
models and may have transmissions geared more for work related tasks
rather than for high performance. However, they have ATV features
such as four low pressure tires, a seat designed to be straddled by
the operator, handlebars for steering controls, and are intended for
use by a single operator. These vehicle must meet ATV requirements.
---------------------------------------------------------------------------

In addition, we received comments that the emissions inventories we
projected for ATVs were too large, and that if we adjusted them
appropriately, we would see that Phase 2 was not needed. This is
provided in detail in the public docket.\56\ We have studied and
evaluated in-depth the new and additional information provided by the
commenters after we published the proposal. As is shown in our revised
analysis, the emissions inventory projections for ATVs have been
reduced by more than 75 percent in response to the significant new
information we received after publishing the proposal. Our analysis of
the appropriate standards for 2006/2007 described above was made using
this new information, and future analysis of Phase 2 standards would
also use these revised inventory numbers. However, it is important to
note that the revised inventories still show that these vehicles
contribute to nonattainment.
---------------------------------------------------------------------------

\56\ Comments of the Motorcycle Industry Council, Inc., and the
Specialty Vehicle Institute of America on the Notice of Proposed
Rulemaking to Establish Mandatory Emission Standards for Nonroad
Large Spark-Ignition Engines and Recreational Engines (Marine and
Land-Based), Air Docket A-2000-01, IV-D-214.
---------------------------------------------------------------------------

Engine-based Standards
California allows ATVs to be optionally tested using the California
ARB utility engine test cycle (SAE J1088) and procedures. In
California, manufacturers using the J1088 engine test cycle option must
meet the California Small Off-Road Engine emission standards. Some
manufacturers do not have chassis testing facilities and at the time
California finalized its program were concerned about the cost of doing
FTP testing for California-only requirements. To use this option,
manufacturers were required by California to submit some emission data
from the various modes of the J1088 test cycles to show that emissions
from these modes were comparable to FTP emissions. Although a good
correlation was not found between the two test cycles, California
allowed this option because the goal of their program was to encourage
four-stroke engine technology in ATVs.
As described above, we are finalizing standards based on vehicle
testing over the FTP that are essentially harmonized with the
California FTP standards. We did not propose a permanent option of
engine testing using J1088 due to strong concerns that the test cycle
misses substantial portions of ATV operation because it contains test
points at only one engine speed. We understand that vehicle testing
would be a significant change for manufacturers who currently conduct
emissions testing on the engine rather than the vehicle for California.
Due to the costs and lead-time requirements associated with switching
to vehicle-based testing, we proposed a transitional program to allow
the J1088 option for models years 2006 through 2008. To facilitate the
phase-in of ATV standards, we proposed to allow manufacturers to
optionally certify ATVs using the California utility cycle and
standards, shown in Table III.C-1, instead of the FTP standards.

Table III.C-1.--California Utility Engine Emission Standards
------------------------------------------------------------------------
Engine displacement HC+NO_X CO
------------------------------------------------------------------------
Less than 225 cc............. 12.0 g/hp-hr.... 300 g/hp-hr
(16.1 g/kW-hr)... (400 g/kW-hr)
Greater than 225 cc.......... 10.0 g/hp-hr..... 300 g/hp-hr
(13.4 g/kW-hr)... (400 g/kW-hr)
------------------------------------------------------------------------

We are finalizing this approach, but will eliminate the J1088
option (including both the test cycle and the utility engine emission
standards) for certification in model year 2009. The last model year to
use the J1088 cycle and emission standards is 2008. We received
comments that the FTP is also not representative of ATV operation and
that the J1088 option should remain available until a new test cycle
and accompanying standards can be developed and made available to
manufacturers. Although it may not be completely representative of ATV
operation, we believe the FTP to be greatly superior to the J1088 test
cycle because the cycle is transient, emissions are measured at a
variety of speeds and it is more likely to result in robust emission-
control designs that reduce emissions in-use. We continue to be very
concerned that the vast majority of ATV operation is missed with the
J1088 test because the engine is tested at only one engine speed. ATV
operation is inherently transient in nature because the user controls
the throttle position to vary vehicle speed. We believe the J1088 test
is not sufficient to ensure robust emissions control development and
use for ATVs. Given the choice of available test procedures for the
long-term, we could not justify retaining the J1088 option.
For small displacement ATVs of 70 cc or less, we proposed that they
would have the permanent option to certify to the proposed FTP-based
ATV standards discussed above or meet the Phase 1 Small SI emission
standards for non-handheld Class 1 engines. These standards are 16.1 g/
kW-hr HC+NO_X and 610 g/kW-hr CO. Manufacturers argued that
ATVs with engine displacements between 70 cc and 99 cc also should be
allowed to certify to the Small SI standards, since the differences
between a 70 cc and 99 cc engine is very small and the ATVs equipped
with 99

[[Page 68271]]

cc engines face the same obstacles with the FTP test cycle as the 70 cc
and below ATVs. They also argued that the Phase 1 Small SI standards
are too stringent for these engines and recommended that EPA adopt the
Phase 2 standards for Class 1B engines of 40 g/kW-hr for
HC+NO_X and 610 g/kW-hr for CO.
We recognize that the vast majority of engine families, including
4-stroke engines, below 100 cc are not certified to the California
standards, which is an indication to us that the standards proposed may
not be feasible for most engines in this size range given the lead time
provided. However, manufacturers did not provide supporting data and we
do not have data to confirm that the level recommended by the
manufacturers would result in an appropriate level of control. We
examined the 2002 model year certification data for non-handheld Small
SI engines certified to the Phase 2 Class I-A and I-B engine standards
(engines below 100 cc). We found that the five engine families
certified to these standards had average emissions for
HC+NO_X of about 25 g/kW-hr. All of these engine families had
CO emissions below 500 g/kW-hr and well below the 610 g/kW-hr level
recommended by manufacturers. We believe these levels are more
representative of the levels that can be achieved with the lead time
provided through the use of 4-stroke engines than the standards
recommended by the manufacturers. Therefore, we are finalizing a 25.0
g/kW-hr HC+NO_X standard and a 500 g/kW-hr CO standard for
ATVs with engine displacements of 99 cc or less. These standards will
be optional to the FTP-based standards and, unlike the J-1088 standards
option for larger displacement engines, the option will not expire. We
are retaining averaging for the HC+NO_X standard but do not
believe averaging would be appropriate for the CO standard. This is
consistent with the approach outlined above for J-1088 standards for
engines above 100 cc.
The ATV standards are phased in at 50% of a manufacturer's
production in 2006 and 100% in 2007. This phase-in applies to a
manufacturer's overall ATV production regardless engine size or which
option a manufacturer chooses for standards for particular models.
New Test Procedure for ATVs
We are comfortable with retaining the FTP as the basis of the long-
term ATV program. However, EPA understands the manufacturers' concerns
regarding the additional facility costs associated with FTP testing for
ATVs. We also recognize that this approach is a significant deviation
from their current practice in the California program. Throughout the
development of the final rule, we have met with manufacturers and the
State of California and have discussed the possibility of developing a
new test cycle for ATVs. We intend to work further with all interested
parties to determine whether a new test cycle and accompanying
standards is appropriate. The standards, if developed for the new test
cycle, would be of equivalent stringency to the FTP standards discussed
above. If we do propose a new test cycle and accompanying standards for
ATVs, it is likely that we would do so in concert with a decision on
whether a second phase of standards is appropriate for ATVs. We are now
developing a Memorandum of Understanding with manufacturers which
describes in detail the steps that will be taken in furtherance of this
task.\57\ Other interested parties including the state of California
will also be invited to participate in this process.
---------------------------------------------------------------------------

\57\ See item IV-G-114, docket A-2000-01.
---------------------------------------------------------------------------

By finalizing the temporary availability of J1088, we are providing
time to develop, and if appropriate, finalize and implement an
alternative to the FTP that meets both the needs of the Agency,
manufacturers and other parties. This allows for our program to remain
harmonized with California during the transition to the new test
procedure. However, we do not support allowing the use of J1088 for a
period any longer than necessary to make this transition. We expect
that developing a new test cycle will be relatively straightforward and
that the MOU process cited above will provide a road map of how we will
proceed. We expect to initiate this effort next year and conclude the
work on the new test cycle in enough time to promulgate it through
rulemaking and to provide industry adequate lead time to implement it
in an orderly manner (nominally three years lead time). If we encounter
unforeseen and unavoidable delays or complications in this process, we
will consider extending the J1088 temporarily as part of our process of
adopting changes to the ATV test cycle through rulemaking. We would
expect such an extension to be at most for one model year.
c. Snowmobiles. We are adopting CO and HC emission standards for
snowmobiles, effective in three phases, as discussed below. As
discussed below, we are also adopting an emissions averaging banking
and trading program for snowmobiles which includes provisions for the
early generation of credits prior to the effective date of the
standards. We are not adopting PM standards for snowmobiles at this
time, because limits on HC emissions will serve to simultaneously
reduce PM and because there are significant complications in accurately
measuring PM that make requiring PM standards difficult in this time
frame. Finally, we are not adopting limits for NO_X for the
first two phases of standards, but manufacturers are required to
measure NO_X emissions and report them in the application for
certification. However, we have included NO_X in the Phase 3
standards to effectively cap NO_X emissions from snowmobiles.
The three phases of standards we are adopting will require
progressively broader application of advanced technologies such as
direct injection two-stroke technology, and four stroke engines. Only
about two percent of current snowmobile production utilizes these
advanced technologies. We expect that about seven percent of new
snowmobiles will have them by 2005. With the Phase 1 standards we
expect that ten percent of snowmobiles will require advanced
technologies (in addition to less advanced emissions controls on most
other snowmobiles). We project that the Phase 2 and Phase 3 standards
will require the application of advanced technology on 50 and 70
percent of new snowmobiles, respectively.
Phase 1 Standards
We are adopting Phase 1 standards largely as proposed for
snowmobiles to take effect for all models starting in the 2006 model
year. However, given that the manufacturers will effectively have only
three years to design and certify snowmobiles prior to the 2006 model
year, as well as the fact that snowmobiles are currently unregulated,
we believe that requiring 100 percent of models to certify in 2006 is
not reasonable. Thus, we are including a phase in of the Phase 1
standards with 50 percent of sales required to comply with the 30
percent reduction standards in 2006 and 100 percent compliance required
in 2007. The standards of 275 g/kW-hr (205 g/hp-hr) for CO and 100 g/
kW-hr (75 g/hp-hr) for HC are to be met on average by each
manufacturer. As described in the proposal, these standards represent a
30-percent reduction from the baseline CO and HC emission rates for
uncontrolled snowmobiles. We expect manufacturers to meet these
standards using a variety of technologies and strategies across their
product lines. For the reasons

[[Page 68272]]

described below, we believe these are the most stringent standards
feasible beginning in the 2006 model year.
Snowmobiles pose some unique challenges for implementing emission-
control technologies and strategies. Snowmobiles are very sensitive to
weight, power, and packaging constraints. Current snowmobile designs
have very high power-to-weight ratios, to address performance
considerations. The desire for low weight has been stated to be a
concern, since weight (and weight distribution) affects handling and
operators occasionally have to drag their sleds out of deep snow. This
has especially been mentioned as a concern in the context of four-
stroke engines given that they are heavier than their two-stroke
counterparts of similar power. However, four-stroke engines have
significantly better fuel economy than two-stroke engines, and for
identical fuel tank sizes, would have significantly greater range. This
of course would be a positive attribute. The size of a fuel tank on a
four-stroke powered snowmobile could be reduced to provide similar
range to that of a similarly powered two-stroke snowmobile, resulting
in offsetting weight savings from both the smaller fuel tank and less
fuel on board. However, this could still represent a change in the
distribution of weight compared to current sleds.
The approach used to control emissions in compliance with the Phase
1 standards will vary according to a given manufacturers product line,
technological capability, long term plans, and other factors. However,
we expect all manufacturers to pursue a mix of technologies. Some
manufacturers may focus more on clean carburetion and associated engine
modifications and apply those widely across their entire product line
with more limited implementation of advanced technology such as four-
stroke and semi direct injection engines. Others may choose to be more
aggressive in applying advanced technologies in their more expensive,
high-performance sleds and be less aggressive in pursuing emission
reductions from their lower-priced offerings to optimize the fit of
different technologies (and their associated costs) to the various
product offerings in the near term. As can be seen on their
websites\58\, all large manufacturers now have limited product
offerings of advanced emissions technology snowmobiles. Snowmobiles
must, on average and according to the phase in schedule, meet the first
phase of emission standards beginning with the 2006 model year. Given
the relative inexperience this industry has with designing effective
snowmobile engines with advanced emissions controls and in certifying
to EPA requirements, it is unlikely that any manufacturer could market
enough of these advanced snowmobiles for model year 2006 to enable it
to meet significantly more stringent standards. Due to the unique
performance requirements for snowmobiles and the relatively short lead
time to modify current engines or design new products, we believe our
2006/2007 standards will be technologically challenging for
manufacturers and will result in cleaner snowmobiles.
---------------------------------------------------------------------------

\58\ http://www.arcticcat.com, http://www.polarisindustries.com,
http://www.skidoo.com, and http://www.yamaha-motor.com.
---------------------------------------------------------------------------

Phase 2 and Phase 3 Standards
We believe the two most viable advanced technologies for use in
snowmobiles are two-stroke direct (or semi-direct) injection technology
and four-stroke engines. All four major snowmobile manufacturers either
currently offer or are planning to offer in the next year or two one or
more of these technologies on a limited number of snowmobile models.
With sufficient resources and lead time for manufacturers, we believe
it would be technologically possible to eventually apply such advanced
technology broadly across most or all of the snowmobile fleet.
Manufacturers have indicated that with enough investment and
sufficient time to design and implement direct injection technology for
snowmobile use, two-stroke engines equipped with direct fuel injection
systems can reduce HC emissions by 70 to 75 percent and reduce CO
emissions by 50 to 70 percent. These projections are based largely on
laboratory prototypes and generally do not account for in-use
deterioration or the need for production compliance margins in the
ultimate certification levels. Certification results for 2002 model
year outboard engines and personal water craft support these
projections.\59\
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\59\ See the snowmobile feasibility discussion in the Final
Regulatory Support Document.
---------------------------------------------------------------------------

In addition to the direct injection two-stroke, a few four-stroke
models are currently available, and more are expected to be introduced
in the next few years. Based on testing of prototypes and other low-
hour engines it appears that advanced four-stroke snowmobiles are
capable of HC reductions ranging from 70 to 95 percent relative to
current technology two-stroke snowmobile engines. However, CO
reductions from four stroke engines vary quite a bit. For four-stroke
engines used in low-power applications, CO reductions of 50 to 80
percent from baseline levels have been reported. However, the majority
of the snowmobile market is for higher-powered performance machines,
and CO reductions from higher powered four stroke engines are lower
than those from low powered four strokes, with expected reductions of
20 to 50 percent from baseline levels. As discussed further in the RSD
and Summary and Analysis of Comments document, we expect that many of
the four-stroke snowmobile models offered in the future will not be
current two-stroke models which have been modified to utilize a four-
stroke engine, but rather new models designed specifically to take
advantage of the unique characteristics of four-stroke engines. Thus,
we expect that the lead time associated with the conversion to four-
stroke engines and optimized sleds is even longer than that needed for
conversion to direct injection two-stroke technology.
It is not obvious to us that either of these advanced technologies
is better than the other or more suited to broad application in the
snowmobile market. Each has its strong points regarding emissions
performance, power, noise, cost, etc. For example, two-stroke engines
equipped with direct fuel injection have the potential to have greater
CO emission reductions than a comparably powered four-stroke engine,
although they would have less HC reductions. For those applications
where a light, powerful, compact engine is desired, a direct injection
two-stroke engine may be preferred. However, for applications where
pure power and speed is desired, a high-performance four-stroke engine
may be preferred. Given the broad range of snowmobile model designs and
applications it is apparent that one of these technologies could be
preferable to the other in some situations. Further, given the broad
range of snowmobile types offered, a mix of advanced technologies would
provide the best opportunity for substantial average emission
reductions while still maintaining customer satisfaction across the
entire range of snowmobile types. Thus, we believe it is most
appropriate to set emission standards for snowmobiles that are not
based entirely on the use of either direct injection two-stroke
technology or four-stroke engines, but rather a mix of the

[[Page 68273]]

two, along with some other technologies in certain applications.
It is our belief that with sufficient resources and lead time,
manufacturers can successfully implement technologies such as two-
stroke direct injection and four-stroke engines in many models in their
respective snowmobile fleets. The question at hand is how broadly this
technology can be practically applied across the snowmobile fleet in
the near term, taking into account factors such as the number of engine
and snowmobile models currently available, and the capacity of the
industry to perform the research and development efforts required to
optimally apply advanced technology to each of these models.
Currently there are only four major snowmobile manufacturers, and
each has different technological capabilities. Of these four, only two
currently manufacturer all of their own engines, one has limited in-
house engine manufacturing operations, the other has none. Beyond this,
there are only two advanced technologies (direct injection two-stroke,
and four stroke) that at this time appear to be feasible to provide
significant reductions in snowmobile emissions. Further, given the
small volume of snowmobile sales compared to other vehicles and
equipment which use similar sized engines, these manufacturers may have
difficulty in working with their engine suppliers to develop and
optimize four-stroke or direct injection two-stroke technology quickly.
Clearly, the nature of the relationship between these snowmobile
manufacturers and their suppliers would result in a less efficient use
of available lead time as compared to the manufacturers that have both
technology and engine manufacturing available in-house. Thus, there is
varying capability within the snowmobile industry to develop and
implement advanced technology in the next five to ten years.
The amount of engine redesign or development work is another
factor. While one snowmobile manufacturer currently offers four
different engine models, the other three, including the two that do not
manufacture their own engines, currently offer eight to twelve engine
models each. Additionally, each of these engine models typically goes
into more than one type of snowmobile. There are a variety of basic
snowmobile types specifically designed for a variety of riding styles
and terrains including high-performance trail riding, high-performance
off-trail riding (including designs specifically for deep snow),
mountain riding, touring (two person snowmobiles designed for use on
groomed trails), and entry level snowmobiles (lower-powered and lower
priced snowmobiles which utilize simpler technology and are
specifically designed to appeal to first time buyers). Some snowmobile
manufacturers also offer snowmobile models specifically for youth, and
utility models for work in cold climates or to facilitate winter sports
such as hauling winter camping gear, or hunting and fishing equipment.
It is not surprising that some of these snowmobile models are much more
popular than others. Thus, there can be quite a difference in the
production volumes of the different snowmobile types, with performance
models typically having large sales volumes, and more unique models
such as utility and youth models selling far fewer units.
Considering the number of snowmobile types, and the fact that each
engine model is typically used in several different snowmobile models,
each manufacturer has potentially dozens of different engine/snowmobile
combinations that it offers. An analysis of the manufacturers current
product offerings shows that while one manufacturer has only about
twelve unique engine/snowmobile model combinations, the other three
offer significantly more--from around 30 to over 50. Each of these
different snowmobile models is designed with specific power needs in
mind, with the engine and clutching specifically suited for the
application style for which the snowmobile was intended. This means
that a given engine model may require slightly different calibrations
for each different snowmobile model in which it is used. While the
advanced technologies are known, they are not ``one size fits all''
technologies. These technologies need to be optimized not only for the
specific engine model, but in some cases for the snowmobile the engine
will be used in as well, as just described.
For all of the reasons just discussed, we believe that it is
necessary to allow two additional years of lead time for compliance
with the proposed Phase 2 standards, and are therefore adopting the
ultimate phase of snowmobile standards effective for the 2012 model
year rather than the 2010 model year as proposed. However, we expect
that between the 2006 and 2012 model years there can and will be
substantial development and application of advanced technologies on
snowmobiles beyond that required in compliance with the Phase 1
standards. We believe that it is important to capture the emission
benefits that these advances present, and are therefore adopting a new
set of Phase 2 standards, effective with the 2010 model year, which
will require 50 percent HC reductions and 30 percent CO reductions from
average baseline levels. The Phase 2 standards are 275 g/kW-hr (205 g/
hp-hr) for CO and 75 g/kW-hr (56 g/hp-hr) for HC. These Phase 2
standards will be followed by Phase 3 standards in 2012 which will
effectively require the equivalent of 50 percent reductions in both HC
and CO as compared to average baseline levels.
We believe that the 2010 and 2012 model years are appropriate for
the second and third phases of snowmobile standards because they allow
an additional four to six years beyond the Phase 1 standards for the
further development and application of advanced emissions control
technology. We expect that the manufacturers will utilize some level of
advanced technology in compliance with the Phase 1 standards, and this
will give the manufacturers some time to evaluate how the advanced
technology they have already applied works in the field as well as give
them several years to work with the certification and compliance
programs before more stringent Phase 2 standards take effect in 2010.
We believe that by the 2010/2012 time frame manufacturers could, at
least in theory, apply advanced technology across essentially their
entire product lines. However, the manufacturers are resource
constrained, and they will need to focus their efforts on compliance
with the Phase 1 and Phase 2 standards prior to the 2010 model year.
There is a need for significant technology development and
manufacturing learning to occur, and there is concern that in this time
frame such technology could not be performance, emissions, and safety
optimized for each application given the number of engine and
snowmobile model combinations that would require optimization. This
would be especially challenging for those manufacturers who rely on
outside suppliers for their engines. Rather, we expect that by the 2012
model year the manufacturers could both apply and optimize advanced
technology to their larger volume families while applying clean
carburetion and electronic fuel injection technology to the rest of
their production. Under this scenario we expect that the manufacturers
could apply optimized advanced technology on around 50 percent of their
production by the 2010 model year, and an additional 20 percent of
their production by the 2012 model year. We do not believe that having
only two

[[Page 68274]]

years lead time between the Phase 2 and Phase 3 standards presents any
problems because compliance with the Phase 3 standards will be achieved
through the broader application of technologies which will already be
applied in compliance with the Phase 2 standards, rather than through
the introduction of new technologies altogether.
As was previously discussed, four-stroke technology has the
potential to significantly reduce HC emissions, even below levels
expected from direct injection two-stroke technology. However, higher
powered four-stroke engines are not currently capable of CO reductions
on the order of those expected from direct injection two-stroke
technology. This is significant given that a very large segment of the
snowmobile market is in higher powered performance sleds. We are
concerned that a straight 50 percent reduction in CO in the Phase 3
standards may deter technology development and constrain the use of
four-stroke technology in this key portion of the snowmobile market. As
the emissions standards become more stringent we believe that it is
important to provide additional flexibility to assure compliance in a
manner which minimizes costs and is consistent with the availability of
technology and the realities of the snowmobile marketplace. Thus, to
allow snowmobile manufacturers the flexibility to base their future
product lines on higher percentages of four-stroke models, we are
adopting a flexible Phase 3 standards scheme that will allow
manufacturers to certify their production to levels which nominally
represent 50 percent reductions in HC and CO. This overall reduction
could be met by other combinations summing to 100 percent such as 70
percent reductions in HC and 30 percent reductions in CO, or any level
between these two points (for example, 60 percent reductions in HC and
40 percent reductions in CO). However, in no case may a manufacturer's
corporate average for the individual pollutants for Phase 3 be less
than 50 percent on HC and 30 percent on CO (the Phase 2 standards).
Some manufacturers have raised safety concerns regarding the use of
advanced technologies on snowmobiles, particularly four-stroke engines
used in high-performance and mountain sleds. In particular, they raised
issues regarding weight and the ability to start the snowmobile in cold
weather. However, we believe these issues can be overcome with
sufficient time and technology. For example, as noted above, smaller
fuel tanks can significantly reduce the weight of four-stroke
snowmobiles. The use of new light-weight materials can also reduce
weight for four-stroke designs. Manufacturers have raised concerns over
cold starting for four-stroke engines because the typical four-stroke
design uses an oil distribution system where the pump and oil are
located in the crankcase (referred to as a ``wet'' sump). During
extremely cold temperatures, the oil becomes thick and provides an
additional load the engine must overcome when starting. However, by
using a ``dry'' sump, where the oil and pump are located in a separate
tank (not in the crankcase), the concern over cold temperature starting
loads due to thickened oil in the crankcase are gone. The new Yamaha
RX-1 four-stroke snowmobile uses a smaller fuel tank and lighter
materials to reduce weight and a dry sump to help cold starting, so
clearly these issues can be addressed.
We believe that, given enough resources and lead time, it is
ultimately feasible at some point beyond the 2012 model year to apply
advanced technology successfully to all snowmobiles and perhaps to even
resolve current design and operating issues with regard to the use of
aftertreatment devices such as catalytic converters. However, it is
difficult to predict at this point when this would be feasible,
especially given the number of smaller volume snowmobile models that
would need development effort once the larger volume models were
optimized in compliance with the Phase 3 standards in 2012. We did
consider standards based on the full application of optimized advanced
technology to all snowmobiles, for example by setting the Phase 3
standards at a level that would require the full application of
advanced technology to all snowmobiles. However, we believe that such
standards are not feasible by 2012 and, we are not confident that we
could choose the appropriate model year beyond 2012 for such standards
given how far in the future such a requirement would be. Such an
approach would also serve to eliminate the benefits associated with the
Phase 3 standards in 2012. There are diverse capabilities and limiting
factors within the industry, and time is needed for an orderly
development and prove out of this advanced technology across the
various models and applications before standards are set which require
its use in all models. Additionally, as these engines have never
previously been regulated or used advanced emission control
technologies in large numbers, we believe it is appropriate to monitor
the development and use of such technologies on snowmobiles before
requiring these technologies for the entire fleet. Thus, we chose not
to set standards at this time based on the optimized application of
advanced technology to all snowmobiles. Nevertheless, we will monitor
the development and application of the advanced technology as
manufacturers work to comply with the Phase 3 standards in 2012 and
will consider a fourth phase of snowmobile standards to take effect
sometime after the 2012 model year.
We have not included a NO_X standard for the first two
phases of the snowmobile regulations because NO_X emissions
from snowmobiles, particularly two-stroke engines, are very small
compared to levels of HC, CO and PM and we believe that stringent
NO_X standards may require the use of technologies that will
lead to increases in HC, PM and CO levels. Technologies that reduce
NO_X are likely to increase levels of HC, PM and CO and vice
versa, because technologies to reduce HC, PM and CO emissions would
result in leaner operation. A lean air and fuel mixture causes
NO_X emissions to increase. These increases are minor,
however, compared to the reductions of HC, CO and PM that result from
these techniques. On the other hand, any attempt to control the
NO_X emissions may have the counter-effect of increasing HC,
CO, and PM emissions, as well as causing the greater secondary PM
concentrations associated with increased HC emissions. This is
especially critical for HC and PM, because NO_X would be
regulated primarily for its effect on secondary PM levels.
We are promulgating a NO_X standard (actually an HC plus
NO_X standard) as part of the third phase of the snowmobile
standards. This standard will essentially cap NO_X emissions
from these engines. The reason we are including such standards in the
final phase of the rule as that the third phase of the rule will result
in increases in the use of four-stroke engines. While four-stroke
engines greatly reduce HC and direct PM levels, they increase levels of
NO_X. While NO_X levels remain substantially lower
than HC and CO levels, they are higher than levels for two-stroke
engines.
Thus, it is appropriate to place a cap on such levels to ensure
that levels do not become so high as to become a substantial concern.
While we are promulgating an effective cap on such emissions, the
standard will not mandate substantial reductions in NO_X.
This is because the

[[Page 68275]]

emissions effect on reducing NO_X from four-stroke engines is
the same as for two-stroke engines; that is, technologies that
substantially reduce NO_X will increase levels of other
pollutants of concern. The only way to reduce NO_X emissions
from four-stroke engines (at the same time as reducing HC and CO
levels) would be to use a three-way catalytic converter. We don't have
enough information at this time on the durability or safety
implications of using a three-way catalyst with a four-stroke engine in
snowmobile applications. Three-way catalyst technology is well beyond
the technology reviewed for this rule and would need substantial
additional review before being contemplated for snowmobiles. Thus,
given the overwhelming level of HC and CO compared to NO_X,
and the secondary PM expected to result from these levels, it would be
premature and possibly counterproductive to require substantial
NO_X reductions from snowmobiles at this time.
2. Are There Opportunities for Averaging, Emission Credits, or Other
Flexibilities?
a. Averaging, banking and trading. Historically, voluntary
emission-credit programs have allowed a manufacturer to certify one or
more engine families at emission levels above the applicable emission
standards, provided that the increased emissions are offset by one or
more engine families certified below the applicable standards. With
averaging alone, the average of all engine families for a particular
manufacturer's production must be at or below that level of the
applicable emission standards. We are adopting separate emission-credit
programs for snowmobiles, off-highway motorcycles, and ATVs. We are
adopting an emission-credit program for the optional ATV engine-based
standards as well as the chassis-based standards.
In addition to the averaging program just described, the emission-
credit program contains banking and trading provisions, which allow
manufacturers to generate emission credits and bank them for future use
in their own averaging program or sell them to another entity. We are
not adopting a credit life limit or credit discounting for these
credits. Unlimited credit life and no discounting increases the
incentive to introduce the clean technologies needed to gain credits.
To generate credits, the engine family's emissions level must be below
the standard, so any credits will result from reducing emissions more
than necessary to meet the standards.
ATVs and Off-highway Motorcycles
Emission credits from off-highway motorcycle and ATVs will be
averaged separately because there are differing degrees of stringency
in the standards for ATVs and off-highway motorcycles long-term and we
do not want off-highway motorcycle credits to dilute the effectiveness
of the ATV standards. This also avoids providing an advantage in the
market to companies that offer both types of products over those that
produce only one type. Also, ATVs certified to the chassis-based
standards or engine-based standards are considered separate averaging
groups with no credit exchanges between the two. We are not allowing
credit exchanges between engine and chassis-based testing because there
is little, if any, correlation between the two test cycles. Without a
strong correlation, it is not possible to establish an exchange rate
between the two programs. For the engine-based (J-1088) ATV standards,
the standards vary by engine size (less than 100 cc, 100 cc up to 225
cc, and 225 cc and greater). We are allowing averaging, banking, and
trading for each of the separate engine-based HC+NO_X
standards with no credit exchanges or averaging between the engine size
categories.
We did not propose an averaging, banking, and trading program for
CO for ATVs and off-highway motorcycles because it was not clear if
such provisions would be needed to implement the expected technologies
or if the need would warrant the additional complexity of an averaging
program. We received comments that the 25 g/km CO standard could be
technologically limiting in some instances. Manufacturers recommended
that EPA drop CO the standard from the program and provided no comments
regarding CO averaging. In addition, our recent testing indicates that
the level of the standards may represent a significant technological
challenge to the manufacturers in some cases.
We are retaining CO standards in the final program, and are
establishing different CO standards for off-highway motorcycles and
ATVs, as discussed in Section III.C.1. For ATVs, we are addressing the
feasibility issues by finalizing a standard of 35 g/km. We are not
including averaging or a credits program at this level. We are also
adopting the 35 g/km CO standard for the optional off-highway
motorcycle program with no averaging or credits program. At the 35 g/km
level, we believe averaging is unnecessary and would greatly reduce the
need to control CO, especially for larger manufacturers who have
several engine families with which to average. The engine-based (J-
1088) standards for CO also do not represent levels of stringency where
we believe averaging would be appropriate or necessary. California
certification test data shows that the engine-based (J-1088) CO
standards can be achieved with reasonable compliance margins.
For the primary off-highway motorcycle program, we are retaining
the proposed 25 g/km CO standard. We are providing the option of
averaging for the 25 g/km CO standard, to help manufacturers balance
the need to control CO while meeting stringent NO_X
requirements. We believe that the final program with averaging for CO
will enable manufacturers to develop a unified emission-control
strategy to control HC, NO_X, and CO, rather than requiring
them to develop unique control strategies driven by the need to meet
the CO standards.
We are adopting FEL caps where we are allowing averaging standards.
For ATVs certified to the 1.5 g/km FTP standard, there will be an FEL
cap of 20 g/km HC+NO_X. This cap will also apply to off-
highway motorcycles certified to the 2.0 g/km NO_X+HC
standard. For off-highway motorcycles certified to the 25 g/km CO
standard, the CO cap will be 50 g/km. For off-highway motorcycles, we
are also finalizing an option that allows manufacturers to certify to
an average HC+NO_X standard of 4.0 g/km, if the manufacturer
certifies all off-highway motorcycles including competition machines.
Under this option, we are limiting FELs to 8.0 g/km. The goal of the
option is to encourage the development and certification of clean
competition products. Without a reasonable FEL limit, manufacturers
could certify two-stroke machines at, or close to, baseline levels.
This is a concern because the majority of manufacturers' product
offerings are likely to be certified below the 4.0 g/km level and
significant credits could be available. We believe the 8.0 g/km limit
ensures significantly cleaner products compared to baseline levels for
competition machines, while providing manufacturers with the incentive
and flexibility to pursue innovative technologies for their competition
products.
As noted above, we have also included engine-based J-1088 standards
for ATVs. The HC+NO_X portion of the J-1088 standards can be
met through averaging and we have included reasonable emissions caps
for these standards as well. For engines certified to the permanent
optional J-1088 standards for ATV engines below 100 cc, the emissions
cap is 40.0 g/kW-hr.

[[Page 68276]]

The NO_X+HC emissions cap is 32.2 g/kW-hr for engine
certified to the temporary J-1088 standards which are available for all
engine sizes.
Snowmobiles
For snowmobiles, we are adopting an emissions averaging and credit
program for all three phases of standards. Averaging is available for
each phase of standards. Once the program begins in 2006, manufacturers
will make a demonstration of compliance with the applicable corporate
average standards at the end of the model year. If a manufacturer has
achieved a corporate average level below the corporate average
standards, then the manufacturer may bank credits. Manufacturers may
bank credits for use in a current phase of standards based on the
difference between their corporate average and the standards. In order
to bank credits for future use under a subsequent phase of standards,
manufacturers may pull engines from their corporate average for the
current phase of standards and certify them early to a future phase of
standards. The credits must be generated based on the difference
between the FEL for those engines and the phase of standards for which
they are intended to be used. The credits may not be carried forward
for use to meet a subsequent phase of standards.
For example, manufacturers may bank Phase 2 credits in 2007 by
removing engines from their 2007 corporate average for one or both
pollutants and certifying the engines to the Phase 2 standards early.
These Phase 2 credits may then be saved for Phase 2, but may not be
used for Phase 3. Manufacturers may also remove only part of an engine
family for purposes of banking credits. Manufacturers may bank credits
after the end of the model year when they have completed their
demonstration of compliance for that year. The Final Rule includes
provisions for banking credits for a single pollutant, with the other
pollutant remaining in the averaging program for the current model
year. For Phase 3, if a manufacturer chooses to bank credits for only
one pollutant, the manufacturer must use an assigned value for the
other pollutant in the Phase 3 standards formula. We are specifying a
value of 90 g/kW-hr for HC+NO_X and 275 g/kW-hr for CO. These
levels ensure no windfall credits using the Phase 3 formula for the
credit-generating engines.
Starting with Phase 3, Family Emission Limits may be set up to the
current average baseline emission levels of 400 g/kW-hr (300 g/hp-hr)
CO and 150 g/kW-hr (110 g/hp-hr) HC. These caps ensure a minimum level
of control for each snowmobile certified under the long-term program.
We believe this is appropriate due to the potential for personal
exposure to very high levels of emissions as well as the potential for
high levels of emissions in areas where several snowmobiles are
operated in a group. We proposed that these limits would be effective
beginning in 2006. We received comments from manufacturers recommending
that we drop the FEL limits because they would create a tremendous near
term workload burden. They commented that manufacturers would need to
modify all product lines for 2006 just to meet the FEL limit. EPA
recognizes that this could be a significant issue in the early years of
the program and could detract from manufacturers' efforts to develop
much cleaner technologies. Thus, we are finalizing the FEL limits only
for Phase 3 and later, beginning in 2012. We believe this helps resolve
the lead-time and workload issues while maintaining the integrity of
the long-term program.
b. Early credits. We believe that allowing manufacturers to
generate credits prior to 2006 has some merit in that it encourages
them to produce cleaner snowmobiles earlier than they otherwise might
and provides early environmental benefits. It would also allow for a
smoother transition to new emission standards in a previously
unregulated industry. However, in the proposal we expressed concern
that an early-credit program could result in the generation of windfall
credits, especially if the credits were generated relative to the
average baseline emissions rates. A manufacturer could choose those
engine families that already emit below the average baseline levels and
certify those families for credit generation purposes without doing
anything to actually reduce their emissions. Clearly this would
undermine any environmental advantages of an early-credit program.
However, we believe that it is possible to design an early-credit
program which provides incentive for the early introduction of cleaner
snowmobiles and also helps ease the transition into the first ever
phase of snowmobile standards while preventing the generation of
windfall credits. The early-credit program described in the following
paragraphs will be available beginning with the 2003 model year. As
with the standard snowmobile emissions averaging, banking and trading
program, credits generated under the early-credit program will be
calculated on a power-weighted basis.
A manufacturer can choose to certify one or more engine families
early for purposes of credit generation. An engine family must at least
meet the Phase 1 standards for both HC and CO to qualify for early
credits, and the credits will be calculated based on the difference
between the certification FEL and the Phase 1 standards. Credits
generated under this option can be used only in compliance with the
Phase 1 standards. Thus, such early credits will expire at the end of
the 2009 model year.
The above discussion of early credits primarily addresses those
snowmobiles that will meet the Phase 1 standards early. However, we
also expect that there will be some engine families introduced prior to
the 2006 model year which could meet Phase 2 standards. For such
engines, a manufacturer may elect to split credits between Phase 1 and
Phase 2. A manufacturer may save credits generated between the
certification FELs and the actual Phase 2 standards for use in Phase 2.
Credits generated between the Phase 1 and Phase 2 standards could be
used for Phase 1 only. Credits generated prior to the start of the
program in 2006 may not be used for Phase 3.
EPA did not receive comments on such programs for off-highway
motorcycle or ATVs and we are not finalizing any additional provisions.
The majority of products currently offered for sale are equipped with
four-stroke engines which raises concerns over the potential for
windfall credits. Due to this issue and the lack of suggestions or
input on the part of commenters, we are not finalizing early credits or
other types of flexibilities for these programs.
c. Nonconformance penalties for recreational vehicles. Section
206(g) of the Act, 42 U.S.C. 7525(g), authorizes EPA to establish
nonconformance penalties (NCPs) for motorcycles and heavy-duty engines
which exceed the applicable emission standard, provided that their
emissions do not exceed an appropriate upper limit. NCPs allow
manufacturers that are technological laggards to temporarily sell their
vehicles by payment of a penalty, rather than being forced out of the
marketplace. One manufacturer suggested that we consider establishing
NCPs for recreational vehicles. Section 213(d) of the Act makes nonroad
standards subject to the provisions of section 206, and directs EPA to
enforce nonroad standards in the same manner as highway vehicles. We
therefore believe that the Act authorizes us to establish NCPs in
appropriate circumstances for nonroad engines and vehicles.
Recreational vehicles are

[[Page 68277]]

similar technologically to highway motorcycles, and NCPs might be
appropriate for recreational vehicles under certain circumstances.
We will consider the need for NCPs two or three years before
compliance with these standards is required. Manufacturers that
determine in that time frame that they are likely to be unable to
comply with the standards should notify us. If we determine that NCPs
are appropriate for recreational vehicles, we would establish
regulations that would specify how to calculate the penalties. While we
have not determined the content of such regulations, it is likely that
they would be similar to our existing NCP regulations for heavy-duty
engines, which are set forth in 40 CFR part 86, subpart L.
3. Are There Voluntary Low-Emission Standards for These Engines?
In the proposal we included a Voluntary Low-Emission Standards
program for recreational vehicles. We did this for two reasons: to
encourage new emission-control technology and to aid the consumer in
choosing clean technologies. We received numerous comments on this
proposed program. The environmental community was supportive of
voluntary standards and encouraged us to adopt permanent labels which
identify the emission performance of the vehicle in a simplistic manner
that would be easily understood by the initial purchaser and any
purchases of used recreational vehicles. Manufacturers of recreational
vehicles ATVs, off-highway motorcycles, and snowmobiles), on the other
hand, did not support voluntary standards. They were supportive of
providing initial purchasers with emission performance information via
temporary consumer labeling, but were opposed to voluntary standards.
Their concern was that voluntary standards or permanent labels could be
used by federal, state, local or any other jurisdictions to limit the
use of recreational vehicles from public lands by allowing access only
to recreational vehicles that meet certain emission criteria.
Manufacturers further argued that our proposed mandatory emission
standards were stringent enough that they would encourage and result in
the use of advanced emission-control technology and that the voluntary
standards would provide no additional incentives.
As stated above, the general purpose of the Voluntary Low-Emission
Standards program is to provide incentives to manufacturers to produce
clean products and thus create market choices for consumers to purchase
these products.\60\ For all three recreational vehicle categories, but
especially for snowmobiles, we are expecting a variety of emission-
control technologies to be used to meet the standards. In all three
categories we expect consumers to have a choice of which technologies
to purchase and that they will base that purchase on an understanding
of key attributes such as cost, performance, noise levels, safety, and
emissions. Thus, an important factor for informing consumer decision is
to provide them information on the relative emissions attributes of a
given model. We believe this can be achieved through a temporary
consumer labeling program without voluntary standards. Therefore, we
are not finalizing a voluntary standard program for recreational
vehicles at this time. We will consider this issue again in the future,
once experience is gained under this program. In addition, given the
manufacturer's opposition, it is not clear that voluntary standards by
themselves would be an effective incentive for manufacturers.
---------------------------------------------------------------------------

\60\ The snowmobile industry (see docket item II-G-221) and a
group of public health and environmental organizations (see docket
item II-G-139) have both expressed their general support for
labeling programs that can provide information on the environmental
performance of various products to consumers.
---------------------------------------------------------------------------

Instead, we will be adopting a consumer labeling program. A label
must be fixed securely to the product prior to arriving at the
dealership but does not have to be permanent and may be removed by the
consumer when placed into use. The label can be in the form of a
removable sticker or decal, or a hang tag affixed to the handlebars or
fuel cap. If a hang tag is used, it must be attached by a cable tie
that cannot be easily removed, except by the ultimate retail consumer.
The label, at a minimum, must include the following information: U.S.
EPA; Clean Air Index (appropriate pollutant, e.g., HC+NO_X,
etc.); manufacturer name; vehicle model with engine description (e.g.,
500 cc two-stroke with direct fuel injection); emission performance
rating scale; explanation of scale; and notice stating that label must
be on vehicle prior to sale and can be removed only by the ultimate
retail consumer. In section 1051.135(g) of the regulations, titled
``How must I label and identify the vehicles I produce?,'' we have
developed several equations that determine what the emission
performance rating scale will be for each category. The scale is based
on a rating system of 1.0 through 10.0. A value of 1.0 would be
assigned for the cleanest vehicle, while the dirtiest vehicle would get
a rating of 10.0.
4. What Durability Provisions Apply?
We are adopting several additional provisions to ensure that
emission controls will be effective throughout the life of the vehicle.
This section discusses these provisions for recreational vehicles. More
general certification and compliance provisions, which apply across
different vehicle categories, are discussed in Sections II and VII,
respectively.
a. How long do my engines have to comply. Manufacturers must
produce off-highway motorcycle and ATV engines that comply over a
useful life of 5 years or until the vehicle accumulates 10,000
kilometers, or for ATVs 1,000 hours, whichever occurs first. We
consider the 10,000-kilometer and 1,000 hour values to be minimum
values for useful life, with the requirement that manufacturers must
comply for a longer period if the average life of their vehicles is
longer than this minimum value.
The values being finalized will harmonize EPA's useful life
intervals with those contained in the California program. We proposed a
significantly longer useful life intervals of 30,000 kilometers based
on our understanding of usage rates for the vehicles at the time of the
proposal. We received comments from manufacturers that we overestimated
vehicle usage and commenters recommended that we harmonize the useful
life intervals with California's. We have lowered our estimate of usage
rates based on available data, including new data provided during the
comment period.
Based on our current estimates of usage, we concur with
manufacturers that harmonization with California is the best approach
for establishing minimum useful life intervals. Generally, this will
allow the same emission test data to be used for certification under
both programs. However, this remains the minimum useful life and longer
useful life intervals could be required in cases where the basic
mechanical warranty of the engine or the advertised operating life is
longer than the minimum interval. Average service life information will
help in making such a determination. The manufacturer can alternatively
base the longer useful life on the average service life of the vehicles
where necessary data are available.
For snowmobiles, the minimum useful life is 5 years, 8,000 km, or
400 hours of operation, whichever occurs first. We based these values
on

[[Page 68278]]

discussions with manufacturers regarding typical snowmobile life, and
on emission-modeling data regarding typical snowmobile usage rates.\61\
As with ATVs and off-highway motorcycles, longer useful life intervals
are required where the basic mechanical warranty of the engine or the
advertised operating life is longer than the minimum interval and the
manufacturer may alternatively base the longer useful life on the
average service life of the vehicles where necessary data are
available.
---------------------------------------------------------------------------

\61\ EPA memorandum, ``Emission Modeling for Recreational
Vehicles,'' from Linc Wehrly to Docket A-2000-01, November 13, 2000
(document II-B-19).
---------------------------------------------------------------------------

b. What are the minimum warranty periods for emission controls. For
off-highway motorcycle, ATVs, and snowmobiles, manufacturers must
provide an emission-related warranty for at least half of the minimum
useful life period. These periods could 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. See Sec. 1051.120 for a description of which components
are emission-related.
We have included in our final rule an optional set of standards for
off-highway motorcycles that would require the certification of
competition motorcycles. However, for those individual vehicles
actually used in organized competition events, it may be appropriate to
exclude competition motorcycles from warranty coverage. Machines used
in competition, even part of the time, may be subject to usage that can
cause premature degradation of the engine and related components.
Competition riders may place a premium on winning at the expense of
engine durability or could otherwise damage the vehicle during the
competition events. In fact, most manufacturers do not offer any
mechanical warranty on vehicles used in competition. In addition,
motorcycles used only for competition may be modified by the user in
ways that alter the emissions characteristics of the vehicle.\62\ We do
not believe it is reasonable to hold manufacturers responsible for the
emission warranty for such vehicles.
---------------------------------------------------------------------------

\62\ While it is possible that the user could make modifications
to their competition off-highway motorcycle that alter the emissions
characteristics of the vehicle, we do not expect tampering to be a
problem for those competition vehicles certifying to our voluntary
standard of 4.0 g/km HC+NO_X because the technologies
required to meet this standard, four-stroke engines and direct fuel
injection two-stroke engines, are inherent to the engine and will be
optimized for maximum engine performance as well as emissions
performance. Thus, any modifications would actually reduce rather
than improve engine performance.
---------------------------------------------------------------------------

c. How do I demonstrate emission durability during certification.
Durability demonstration for off-highway motorcycles, ATVs, and
snowmobiles includes a requirement to run the engines long enough to
develop and justify the full life deterioration factor. This allows
manufacturers to generate a deterioration factor that helps ensure that
the engines will continue to control emissions over a lifetime of
operation. Snowmobiles also must run out to the end of the useful life
for purposes of durability demonstration and generating deterioration
factors.
d. What maintenance is allowed during service accumulation. For
vehicles certified to the minimum useful life, emission-related
maintenance is generally not allowed during service accumulation. The
only maintenance that may be done must be (1) regularly scheduled, (2)
unrelated to emissions, and (3) technologically necessary. This
typically includes changing engine oil, oil filter, fuel filter, and
air filter.
5. Do These Standards Apply to Alternative-Fueled Engines?
These standards apply to all spark-ignited recreational vehicles,
without regard to the type of fuel used. However, because we are not
aware of any alternative-fueled recreational vehicles sold into the
U.S. market, we are not adopting extensive special provisions to
address them at this time.
6. Is EPA Controlling Crankcase Emissions?
We are requiring that new off-highway motorcycles and ATVs not emit
crankcase vapors directly to the atmosphere. This requirement will
phase in beginning in 2006 and be fully phased in by 2007. California's
regulations for off-highway motorcycles and ATVs, which has been in
effect since 1997, also prohibits the venting of crankcase vapors into
the atmosphere. The major ATV manufacturers sell many of their
California certified ATV models federally as 50-state applications.
Thus, many ATVs sold federally already control crankcase emissions. The
only exceptions could be some of the small youth ATV models that are
imported from Asia.
The typical control strategy used to control crankcase emissions is
to route the crankcase vapors back to the engine intake. This is
consistent with our previous regulation of crankcase emissions from
such diverse sources as highway motorcycles, outboard and personal
water craft marine engines, locomotives, and passenger cars. We have
data from California ARB showing that a performance-based four-stroke
off-highway motorcycle experienced considerably higher tailpipe
emission results when crankcase emissions were routed back into the
intake of the engine, illustrating the potentially high levels of
crankcase emissions that exist.\63\
---------------------------------------------------------------------------

\63\ ``Closed Crankcase Exhaust Emissions from Four-Stoke
Competition Off-highway Motorcycle,'' EPA memo from L. Wehrly to
Docket A-2000-01, September 10, 2001 (document II-B-25).
---------------------------------------------------------------------------

New snowmobiles must also have closed crankcases, beginning in
2006. This requirement is relevant only for four-stroke snowmobiles,
however, since two-stroke engines, by virtue of their operation, have
closed crankcases. Information on the costs and benefits of this action
can be found in the Final Regulatory Support Document.

D. Testing Requirements

1. What Duty Cycles Are Used To Measure Emissions?
Testing a vehicle or engine for emissions typically consists of
exercising it over a prescribed duty cycle of speeds and loads,
typically using a chassis or engine dynamometer. The nature of the duty
cycle used for determining compliance with emission standards during
the certification process is critical in evaluating the likely emission
performance of engines designed to those standards. Duty cycles must be
relatively comparable to the way equipment is actually used because if
they are not, then compliance with emission standards would not assure
that emissions from the equipment are actually being reduced in use as
intended.
a. Off-highway Motorcycles and ATVs. For testing off-highway
motorcycles and ATVs, we specify the current highway motorcycle test
procedure be used for measuring emissions. The highway motorcycle test
procedure is very similar to the test procedure as used for light-duty
vehicles (i.e., passenger cars and trucks) and is referred to as the
Federal Test Procedure (FTP). The FTP for a particular class of engine
or equipment is actually the aggregate of all of the emission tests
that the engine or equipment must meet to be certified. However, the
term FTP has also been used traditionally to refer to the exhaust
emission test based on the Urban Dynamometer Driving Schedule (UDDS),
also referred to as the LA-4 (Los Angeles Driving Cycle i4).
The UDDS is a chassis dynamometer driving cycle that consists of
numerous ``hills''

[[Page 68279]]

which represent a driving event. Each hill includes accelerations,
steady-state operation, and decelerations. There is an idle between
each hill. The FTP consists of a cold start UDDS, a 10-minute soak, and
a hot start. The emissions from these three separate events are
collected into three unique bags. Each bag represents one of the
events. Bag 1 represents cold transient operation, Bag 2 represents
cold stabilized operation, and Bag 3 represents hot transient
operation.
For highway motorcycles, we have three classes based on engine
displacement, with Class I (50 to 169 cc) being the smallest and Class
III (280 cc and over) being the largest. The highway motorcycle
regulations allow Class I motorcycles to be tested on a less severe
UDDS cycle than the Class II and III motorcycles. This is accomplished
by reducing the acceleration and deceleration rates on some the more
aggressive ``hills.'' We proposed to use this same class/cycle
distinction for off-highway motorcycles and ATVs. In other words, we
proposed that off-highway motorcycles and ATVs with an engine
displacement at or below 169 cc would be tested over the FTP test cycle
for Class I highway motorcycles. We proposed that off-highway
motorcycles and ATVs with engine displacements greater than 169 cc
would be tested over the FTP test cycle for Class II and Class III
highway motorcycles. We requested comment on the appropriateness of
allowing the use of the Class I test cycle for all ATVs.
Manufacturers have expressed concerns over the appropriateness of
testing ATVs using the FTP and the ability of some ATVs to be run on
the test cycle. Manufacturers recommended for FTP testing, that all
ATVs be tested over the Class I cycle. Manufacturers stated that the
Class I cycle top speed of 36 mph would be ``much more representative''
of ATV operation than the 57 mph top speed of the Class III cycle.
Manufacturers also noted that California FTP testing is based on the
use of the Class I cycle for all ATVs and that the EPA program would
need to be changed allow for harmonization. Manufacturers did not raise
these same concern for off-highway motorcycles which are tested in
accordance with the highway motorcycle classifications for California.
After considering this issue further, we concur with the
manufacturer's comments and are finalizing the Class I cycle for all
ATVs. One of the objectives of the final program is to allow
harmonization with California and this change is fundamental in the
manufacturers' ability to use the same FTP test data for both programs.
Also, the average speeds of in-use ATVs appear to be significantly
lower than we estimated in the analysis for the proposal (8-13 mph
compared to 20 mph). The new data on ATV usage alleviates concerns that
the lower speeds of the Class I test cycle might miss significant high-
speed ATV operation. The change in the test procedure is directionally
consistent with this new data. In addition, the change in test
procedure will enable ATVs in general to be tested over the FTP with
fewer issues concerning the ability of the vehicles to operate over the
driving cycle. We are finalizing the test procedure requirements as
proposed for off-highway motorcycles. We believe that the
manufacturer's concerns regarding the FTP are also addressed by the
option to test the smallest ATVs (up to 100 cc) to J-1088 standards
permanently. These vehicles are typically governed to top speeds below
the 36 mph contained in the Class I FTP cycle. Also, the small
displacement ATVs may be most strenuously tested (i.e., more operation
at high loads) on the FTP due to their lower horsepower output.
We acknowledge that chassis dynamometers for ATVs could be costly
to purchase and difficult to put in place in the near term, especially
for smaller manufacturers. As discussed in Section III.C.1.b, we are
allowing the use of the J1088 engine test cycle as a transitional
option through model year 2008. The J1088 option expires after 2008 and
the FTP becomes the required test cycle in 2009. As noted above, EPA is
currently in discussions with ATV manufacturers to determine whether a
new test cycle is appropriate. The J1088 may be discontinued earlier
than 2009 if another test procedure is implemented.
b. Snowmobiles. We are adopting the snowmobile duty cycle developed
by Southwest Research Institute (SwRI) in cooperation with the
International Snowmobile Manufacturers Association (ISMA) for all
snowmobile emission testing.\64\ The test procedure consists of two
main parts; the duty cycle that the snowmobile engine operates over
during testing and other testing protocols surrounding the measurement
of emissions (sampling and analytical equipment, specification of test
fuel, atmospheric conditions for testing, etc.). While the duty cycle
was developed specifically to roughly approximate snowmobile operation,
many of the testing protocols are well established in other EPA
emission-control programs and have been simply adapted where
appropriate for snowmobiles.
---------------------------------------------------------------------------

\64\ ``Development and Validation of a Snowmobile Engine
Emission Test Procedure,'' Jeff J. White, Southwest Research
Institute and Christopher W. Wright, Arctic Cat, Inc., Society of
Automotive Engineers paper 982017, September, 1998. (Docket A-2000-
1; document II-D-05).
---------------------------------------------------------------------------

The snowmobile duty cycle was developed by instrumenting several
snowmobiles and operating them in the field in a variety of typical
riding styles, including aggressive (trail), moderate (trail), double
(trail with operator and one passenger), freestyle (off-trail), and
lake driving. A statistical analysis of the collected data produced the
five mode steady-state test cycle is shown in Table III.D-1. This duty
cycle is the one that was used to generate the baseline emissions
levels for snowmobiles, and we believe it is the most appropriate for
demonstrating compliance with the snowmobile emission standards at this
time.

Table III.D-1.--Snowmobile Engine Test Cycle
----------------------------------------------------------------------------------------------------------------
Mode
Engine parameter ---------------------------------------------------------------------
1 2 3 4 5
----------------------------------------------------------------------------------------------------------------
Normalized Speed.......................... 1.00 0.85 0.75 0.65 Idle
Normalized Torque......................... 1.00 0.51 0.33 0.19 0.00
Relative Weighting (in percent)........... 12 27 25 31 5
----------------------------------------------------------------------------------------------------------------

The rest of the testing protocol is largely derived from our
regulations for marine outboard and personal water craft engines, as
recommended in the SwRI/ISMA test cycle development work (61 FR 52088,
October 4, 1996).

[[Page 68280]]

The testing equipment and procedures from that regulation are generally
appropriate for snowmobiles, including the provisions for raw exhaust
gas sampling which are being adopted here for snowmobiles.
Unlike marine engines, however, snowmobiles tend to operate in cold
ambient temperatures. Thus, some provision needs to be made in the
snowmobile test procedure to account for the colder ambient
temperatures typical of snowmobile operation. Since snowmobile
carburetors are jetted for specific ambient temperatures and pressures,
appropriate accounting for typical operating temperatures is important
to assure that anticipated emissions reductions actually occur in use.
We proposed that snowmobile engine inlet air temperature be between -
15[deg]
C and -5[deg]
C (5[deg] F and 23[deg] F), but that the ambient
temperature in the test cell not be required to be refrigerated. We
received comments stating that this approach would be expensive due to
the need for refrigeration equipment, pointing out that the snowmobile
manufacturers do not currently have the capacity for cold testing.
Further, we received comments that accurate emissions results can be
obtained using appropriate jetting determined by extrapolating from the
manufacturer's jet chart (if necessary).
We agree that emissions can be accurately measured at higher
ambient temperatures provided that the proper compensation be made in
the fueling system. For carbureted engines this means jetting the
engine appropriately for the test temperature. For electronically
controlled engines this doesn't tend to be an issue because such
technology generally includes temperature compensation in its control
algorithms. However, one manufacturer stated that for snowmobiles that
have electronically controlled engines, it would be preferable and
environmentally appropriate to test with colder inlet temperatures.
Thus, we are adopting the option to allow snowmobile testing using
either cold engine inlet air temperatures between -15[deg]
C and -
5[deg]
C (5[deg]
F and 23[deg] F) or warm engine inlet air temperatures
between 20[deg]
C and 30[deg]
C (68[deg] F and 86[deg] F). However,
depending on the location of the air box where inlet air enters the
engine intake system, the inlet temperature could be considerably
warmer than ambient conditions. For a snowmobile that does not have
temperature compensating capabilities, it could be possible to get a
moderate emission reduction due to the increase in air density that
results at colder temperatures from the artificially induced test inlet
air. These emission reductions would not occur in real operation since
actual inlet air would be warmer. Therefore, to use the colder inlet
temperature option, a manufacturer must demonstrate that for the given
engine family, the temperature of the inlet air within the air box is
consistent with the inlet-air temperature test conditions.
2. What Fuels Will Be Used During Exhaust Emission Testing?
We are adopting fuel specifications as proposed for all
recreational vehicles that we have specified for 2004 and later light-
duty vehicles.
3. Are There Production-Line Testing Provisions for These Engines?
Recreational vehicle or engine manufacturers must perform emission
tests on a small percentage of their production as it leaves the
assembly line to ensure that production vehicles operate at certified
emission levels. The broad outline of this program is discussed in
Section II.C.4 above. Production-line testing must be performed using
the same test procedures as for certification testing.

E. Special Compliance Provisions

As described in Section XI.B, the report of the inter-agency Small
Business Advocacy Review Panel addresses the concerns of small-volume
manufacturers of recreational vehicles. We proposed to adopt the
provisions recommended by the panel and received comments on the
proposals. We are finalizing the provisions below as proposed, with the
modifications as noted.
Off-Highway Motorcycles and ATVs
To identify representatives of small businesses for this process,
we used the definitions provided by the Small Business Administration
for motorcycles, ATVs, and snowmobiles (fewer than 500 employees).
Eleven small businesses agreed to serve as small-entity
representatives. These companies represented a cross-section of off-
highway motorcycle, ATV, and snowmobile manufacturers, as well as
importers of off-highway motorcycles and ATVs.
As discussed above, our emission standards for off-highway
motorcycles and ATVs will likely necessitate the widespread use of
four-stroke engines. Most small-volume off-highway motorcycle and ATV
importers--and to a lesser degree, small-volume manufacturers--
currently use two-stroke engines. While four-stroke engines are common
in motorcycles and ATVs in general, their adoption by any manufacturer
is still a significant business challenge. Small manufacturers of these
engines may face additional challenges in certifying engines to
emission standards, because the cost of certification would be spread
over the relatively few engines they produce. These higher per-unit
costs may place small manufacturers at a competitive disadvantage
without specific provisions to address this burden.
We are applying the flexibilities described below to engines
produced or imported by small entities with combined off-highway
motorcycle and ATV annual sales of fewer than 5,000 units. The inter-
agency panel recommended these provisions to address the potentially
significant adverse effects on small entities of an emission standard
that may require conversion to four-stroke engines. The 5,000-unit
threshold is intended to focus these flexibilities on those segments of
the market where the need is likely to be greatest and to ensure that
the flexibilities do not result in significant adverse environmental
effects during the period of additional lead-time recommended
below.\65\ In addition, we are limiting some or all of these
flexibilities to companies that are in existence or have product sales
at the time we proposed emission standards to avoid creating arbitrary
opportunities in the import sector, and to guard against the
possibility of corporate reorganization, entry into the market, or
other action for the sole purpose of circumventing emission standards.
---------------------------------------------------------------------------

\65\ For example, importers may have access to large supplies of
vehicles from major overseas manufacturers and potentially could
substantially increase their market share by selling less expensive
noncomplying products.
---------------------------------------------------------------------------

Snowmobiles
There are only a few small snowmobile manufacturers and they sell
only a few hundred sleds a year, which represents less than 0.5 percent
of total annual production. Therefore, the per-unit cost of regulation
may be significantly higher for these small entities because they
produce very low volumes. Additionally, these companies do not have the
design and engineering resources to tackle compliance with emission
standard requirements at the same time as large manufacturers and tend
to have limited ability to invest the capital necessary to conduct
emission testing related to research, development, and certification.
Finally, the requirements of the snowmobile program may be infeasible
or highly impractical because some small-volume

[[Page 68281]]

manufacturers may have typically produced engines with unique designs
or calibrations to serve niche markets (such as mountain riding). The
new snowmobile emission standards may impose significant economic
hardship on these few manufacturers whose market presence is small. We
therefore believe significant flexibility is necessary and appropriate
for this category of small entities, as described below.
Flexibilities
1. Additional lead time. We are adopting a delay of two years
beyond the date larger businesses must comply to ease the burden for
small businesses. This will provide extra time to develop technology
and, in the case of importers, extra time to resolve supplier issues
that may arise. The two-year delay also applies to the timing of the
Phase 2 standards for snowmobiles.
In addition, for small snowmobile manufacturers, the emission
standards phase in over an additional two years at a rate of 50
percent, then 100 percent. Phase 1 phases in at 50/50/100 percent in
2008/2009/2010 and Phase 2 phases in at 50/50/100 percent in 2012/2013/
2014.
2. Design-based certification. The process of certification is a
business cost and lead time issue that may place a disproportionate
burden on small entities, particularly importers. Certification is a
fixed cost of doing business, which is potentially more burdensome on a
unit-cost basis for small entities. It is potentially an even greater
challenge, since some small entities will either contract emission
testing to other parties or, in the case of importers, perhaps rely on
off-shore manufacturers to develop and certify imported engines.
Small-volume manufacturers may use design-based certification,
which allows us to issue a certificate to a small business for the
emission-performance standard based on a demonstration that engines or
vehicles of a similar design criteria meet the standards of the
individual engine family. The small vehicle manufacturer must
demonstrate that their engine uses a design similar to or superior to
one that is being used by other manufacturers that has been shown
through prior emission testing to meet the standards. The demonstration
must be based in part on emission test data from engines of a similar
design. Under a design-based certification program, a manufacturer
provides evidence in the application for certification that an engine
or vehicle meets the applicable standards for its useful life based on
comparing its design (for example, the use a four-stroke engine,
advanced fuel injection, or any other particular technology or
calibration) to that of a previously tested engine. The design criteria
might include specifications for engine type, calibrations (spark
timing, air /fuel ratio, etc.), and other emission-critical features,
including, if appropriate, catalysts (size, efficiency, precious metal
loading). Manufacturers submit adequate engineering and other
information about their individual designs showing that they will meet
emission standards for the useful life.
3. Broaden engine families. Small businesses may define their
engine families more broadly, putting all their models into one engine
family (or more) for certification purposes. Manufacturers may then
certify their engines using the ``worst-case'' configuration within the
family.
A small manufacturer might need to conduct certification emission
testing rather than pursuing design-based certification. Such a
manufacturer would likely find broadened engine families useful.
4. Production-line testing waiver. As discussed above,
manufacturers must test a small sampling of production engines to
ensure that production engines meet emission standards. We are waiving
production-line testing requirements for small manufacturers. This will
eliminate or substantially reduce production-line testing requirements
for small businesses.
5. Use of assigned deterioration factors for certification. Small
manufacturers may use deterioration factors assigned by EPA. Rather
than performing a durability demonstration for each family for
certification, manufacturers may elect to use deterioration factors
determined by us to demonstrate emission levels at the end of the
useful life, thus reducing the development and testing burden. This
might be a very useful and cost-beneficial option for a small
manufacturer opting to perform certification emission testing instead
of design-based certification.
6. Using emission standards and certification from other EPA
programs. A wide array of engines certified to other EPA programs may
be used in recreational vehicles. For example, there is a large variety
of engines certified to EPA lawn and garden standards (Small SI).
Manufacturers of recreational vehicles may use engines certified to any
other EPA standards for five years. Under this approach, engines
certified to the Small SI standards may be used in recreational
vehicles. These engines would then meet the Small SI standards and
related provisions rather than those adopted in this document for
recreational vehicles. Small businesses using these engines will not
have to recertify them, as long as they do not alter the engines in a
way that might cause it to exceed the emission standards it was
originally certified to meet. Also, the recreational vehicle
application may not be the primary intended application for the engine.
Additionally, a certified snowmobile engine produced by a large
snowmobile manufacturer may be used by a small snowmobile manufacturer,
as long as the small manufacturer did not change the engine in a way
that might cause it to exceed the snowmobile emission standards. This
provides a reasonable degree of emission control. For example, if a
manufacturer changed a certified engine only by replacing the stock
exhaust pipes with pipes of similar configuration or the stock muffler
and air intake box with a muffler and air box of similar air flow, the
engine would still be eligible for this flexibility option, subject to
our review. The manufacturer may also change the carburetor to have a
leaner air-fuel ratio without losing eligibility. The manufacturer in
such cases could establish a reasonable basis for knowing that
emissions performance is not negatively affected by the changes.
However, if the manufacturer changed the bore or stroke of the engine,
it would no longer qualify, as emissions might increase beyond the
level of the standard.
7. Averaging, banking, and trading. For the overall program, we are
adopting corporate-average emission standards with opportunities for
banking and trading of emission credits. We expect the averaging
provisions to be most helpful to manufacturers with broad product
lines. Small manufacturers and small importers with only a few models
might not have as much opportunity to take advantage of these
flexibilities. However, we received comment from one small manufacturer
supporting these types of provisions as a critical component of the
program. Therefore, we are adopting corporate-average emission
standards with opportunities for banking and trading of emission
credits for small manufacturers.
8. Hardship provisions. We are adopting provisions to address
hardship circumstances, as described in Section VII.C.
9. Unique snowmobile engines. Even with the broad flexibilities
described above, there may be a situation where a small snowmobile
manufacturer cannot comply. Therefore, we are adopting an additional
provision to allow a small

[[Page 68282]]

snowmobile manufacturer to petition us for relaxed standards for one or
more engine families. The manufacturer must justify that the engine has
unique design, calibration, or operating characteristics that make it
atypical and infeasible or highly impractical to meet the emission-
reduction requirements, considering technology, cost, and other
factors. At our discretion, we may then set an alternative standard at
a level between the prescribed standard and the baseline level, which
would likely apply until the engine family is retired or modified in a
way that might alter emissions. These engines will be excluded from
averaging calculations. We proposed that this provision be limited to
300 snowmobiles per year. However, we received comment that this limit
is too restrictive to be of much assistance to small businesses. Based
on this comment we are adopting a limit for this provision of 600
snowmobiles per year.

F. Technological Feasibility of the Standards

1. Off-highway Motorcycles and ATVs
We believe the new emission standards are technologically feasible
given the availability of emission-control technologies, as described
below.
a. What are the baseline technologies and emission levels? As
discussed earlier, off-highway motorcycles and ATVs are equipped with
relatively small (48 to 650 cc) high-performance two-or four-stroke
single cylinder engines that are either air-or liquid-cooled.\66\ Since
these vehicles are unregulated outside of the state of California, the
main emphasis of engine design is on performance, durability, and cost
and thus they generally have no emission controls. The fuel systems
used on these engines are almost exclusively carburetted. Two-stroke
engines lubricate the piston and crankshaft by mixing oil with the air
and fuel mixture. This is accomplished by most contemporary two-stroke
engines with a pump that sends two-cycle oil from a separate oil
reserve to the carburetor where it is mixed with the air and fuel
mixture. Some less expensive two-stroke engines require that the oil be
mixed with the gasoline in the fuel tank. Four-stroke engines inject
oil via a pump throughout the engine as the means of lubrication. With
the exception of those vehicles certified in California, most of these
engines are unregulated and thus have no emission controls. For ATVs,
approximately 80-percent use four-stroke engines while only 55 percent
of off-highway motorcycles use four-stroke engines. The average HC
emissions for two-stroke engines are about 35 g/km, while the average
for four-stroke engines are 1.5 g/km. CO emissions levels are very
similar between the types of engines with two-stroke levels of
approximately 34 g/km and four-stroke levels of 30 g/km. For
performance and durability reasons, off-highway motorcycle and ATV
engines all tend to operate with a ``rich'' air and fuel mixture. That
is, they operate with excess fuel, which enhances performance and
allows engine cooling to promote longer engine life. However, rich
operation results in high levels of HC, CO, and PM emissions. Also,
two-stroke engines tend to have high scavenging losses, where up to a
third of the unburned air and fuel mixture goes out of the exhaust
resulting in high levels of HC emissions.
---------------------------------------------------------------------------

\66\ The engines are small relative to automotive engines. For
example, automotive engines typically range from one liter to well
over five liters in displacement, whereas off-highway motorcycles
range from 0.05 liters to 0.65 liters.
---------------------------------------------------------------------------

b. What technology approaches are available to control emissions?
Several approaches are available to control emissions from off-highway
motorcycles and ATVs. The simplest approach consists of modifications
to the base engine, fuel system, cooling system, and recalibration of
the air and fuel mixture. These changes may include adjusting valve
timing for four-stroke engines, changing from air-to liquid-cooling,
and using advanced carburetion techniques or electronic fuel injection
instead of traditional carburetion systems. Other approaches may
include secondary air injected into the exhaust, an oxidation or three-
way catalyst, or a combination of secondary air and a catalyst. The
engine technology that may have the most potential for maximizing
emission reductions from two-stroke engines is direct fuel injection.
Direct fuel injection is able to reduce or even eliminate scavenging
losses by pumping only air through the engine and then injecting fuel
into the combustion chamber after the intake and exhaust ports have
closed. Using oxidation catalysts with direct injection may reduce
emissions even further. Finally, converting from two-stroke to four-
stroke engine technology will significantly reduce HC emissions. All of
these technologies have the capability to reduce HC and CO emissions.
We expect none of these technologies to negatively affect noise,
safety, or energy factors. Fuel injection can improve the combustion
process which can result in lower engine noise. The vast majority of
four-stroke engines used in off-highway motorcycles and ATVs are
considerably quieter than their two-stroke counterparts. Fuel injection
has no impact on safety and four-stroke engines often have a more
``forgiving'' power band which means the typical operator may find the
performance of the machine to be more reasonable and safe. Fuel
injection, the enleanment of the air and fuel mixture and four-stroke
technology all can result in significant reductions in fuel
consumption.
c. What technologies are most likely to be used to meet emission
standards?
Four-Stroke Engines
Most manufacturers have experience with four-stroke engine
technology and currently have several models powered by four-stroke
engines. This is especially true in the ATV market where four-stroke
engines account for 80 percent of sales. Because four-stroke engines
have been so prevalent over the last 10 years in the off-highway
motorcycle and ATV industry, manufacturers have developed a high level
of confidence in four-stroke technology and its application.
Manufacturers of off-highway motorcycles and ATVs utilizing four-
stroke engines will need to make some minor calibration changes and
improvements to the carburetor to meet emission standards for the 2006
model year. Some of these modifications may have already been
incorporated in response to California requirements. The calibration
changes will most likely consist of reducing the amount of fuel in the
air-fuel mixture. This is commonly referred to as leaning out the air-
fuel ratio. Although four-stroke engines produce considerably lower
levels of HC than two-stroke engines, the four-stroke engines used in
off-highway motorcycles and ATVs all tend to be calibrated to operate
with a rich air-fuel ratio for performance and durability benefits.
This rich operation results in high levels of CO, since CO is formed in
the engine when there is a lack of oxygen to complete combustion. We
believe that many of these engines are calibrated to operate richer
than needed, because they have either never had to consider emissions
when optimizing air-fuel ratio or those that are certified to the
California standards can operate richer because the California ATV CO
standards are fairly lenient. Carburetors with tighter tolerances
ensure more precise flow of fuel and air, resulting in better fuel
atomization (i.e., smaller fuel droplets), better combustion, and lower
emissions.
In addition to converting to four-stroke technology and making some
minor calibration and carburetion improvements to meet the 2006

[[Page 68283]]

emission standards, manufacturers may need to use secondary air
injection on some models. Secondary air has been used by passenger cars
and highway motorcycles for many years as a means to help control HC
and CO. The hot exhaust gases coming from the combustion chamber
contain significant levels of unburned HC and CO. If sufficient oxygen
is present, these gases will continue to react in the exhaust system,
reducing the amount of pollution emitted into the atmosphere. To assure
that sufficient oxygen is present in the exhaust, air is injected into
the exhaust system. For off-highway motorcycles and ATVs, the
additional air can be injected into the exhaust manifold using a series
of check valves which use the normal pressure pulsations in the exhaust
manifold to draw air from outside, commonly referred to as pulse air
injection. We have tested several four-stroke ATVs with secondary air
injected into the exhaust manifold and found that the HC and CO
emission levels were below the standards (further details of our
secondary air testing are described in the Final Regulatory Support
Document).
A small number of models in California have been equipped with
secondary air technology. It is likely that some manufacturers will opt
to use secondary air systems to reduce emissions in addition to
enleanment strategies to meet EPA standards. We believe this may be
especially true for ATVs meeting the 1.5 g/km HC+NO_X
standard. Using these systems would also provide manufacturers with
more flexibility within the averaging scheme and would allow them to
avoid any negative affects on performance that could accompany
excessive enleanment. Also, several models are not certified to
California standards, including some four-stroke models. Manufacturers
may use secondary air on a more widespread basis to bring all models
into compliance.
Since the emission standards address HC + NO_X, as well
as CO, manufacturers will have to use an emission-control strategy or
technology that doesn't cause NO_X emissions to increase
disproportionately. However, since all of these vehicles operate with
rich air-fuel ratios, as discussed above, NO_X levels from
these engines are generally low and strategies designed to focus on HC
reduction allow manufacturers to meet emission standards with no
significant increase in NO_X levels.
Two-Stroke Engines
Off-highway motorcycles and ATVs using two-stroke engines will
present a greater challenge for compliance with emission standards.
Since baseline HC and CO emission levels are so high for two-stroke
engines, it would be very difficult for any two-stroke engine to meet
our standards with current production technologies. Although catalysts
have been used for two-stroke powered mopeds, scooters, and small
displacement highway motorcycles in Europe and Asia, the standards and
test cycles are significantly different from ours and there is no way
to make reasonable comparisons. We have not performed any testing, nor
are we aware of any emission test data on the use of catalysts on ATV
and off-highway motorcycle two-stroke engines. Therefore, we do not
believe that catalysts would be available for two-stroke engines that
would meet our standards in the time frame necessary to comply with our
program. Direct fuel injection has been successfully applied to two-
stroke engines used in marine personal water craft, outboard engines,
and small mopeds and scooters and is just now being looked at for off-
highway motorcycle applications. However, as discussed below, even this
advanced technology cannot meet our standards alone.
As described in Section III.C.1.a, we are including an optional
standard for off-highway motorcycles of 4.0 g/km HC + NO_X,
for manufacturers willing to certify competition motorcycles that would
otherwise be exempt from emission standards. We received comment from
REV! Motorcycles in support of this level. Rev! plans to manufacture
two-stroke off-highway motorcycles equipped with direct injection.
Based on an early analysis of the technology, REV! requested that EPA
consider establishing a 4.0 g/km standard to allow them to pursue the
technology and have a realistic opportunity to meet emission standards.
According to their comments, they believe that their engines will be
capable of meeting the 4.0 g/km standard without the use of a catalyst.
Perhaps most importantly, REV! believes that this is a viable
technology approach for competition models, which have very high
baseline emissions.
REV! shared their plans and emissions projections for a single
prototype model of competition motorcycle. Production units, additional
models, or motorcycles produced by other manufacturers using similar
technologies may not be able to achieve the 4.0 g/km level. The 4.0 g/
km level represents an HC reduction of 90 percent or more from baseline
levels for some competition motorcycles, which is likely to be very
challenging. This is one reason EPA is also allowing averaging,
banking, and trading for this option. Averaging will provide
flexibility to manufacturers who have some models that, while very
clean relative to baseline levels, are above the 4.0 g/km standard.
Manufacturers will be able to use credits, for example, from the sale
of four-stroke machines with emissions below 4.0 g/km to achieve the
4.0 g/km standard on average.
2. Snowmobiles
a. What are the baseline technologies and emission levels? As
discussed earlier, snowmobiles are equipped with relatively small high-
performance two-stroke two and three cylinder engines that are either
air-or liquid-cooled. Since these vehicles are currently unregulated,
the main emphasis of engine design is on performance, durability, and
cost and thus they have no emission controls. The fuel system used on
these engines are almost exclusively carburetors, although some have
electronic fuel injection. Two-stroke engines lubricate the piston and
crankshaft by mixing oil with the air and fuel mixture. This is
accomplished by most contemporary two-stroke engines with a pump that
sends two-cycle oil from a separate oil reserve to the carburetor where
it is mixed with the air and fuel mixture. Some less expensive two-
stroke engines require that the oil be mixed with the gasoline in the
fuel tank. Snowmobiles currently operate with a ``rich'' air and fuel
mixture. That is, they operate with excess fuel, which enhances
performance and allows engine cooling which promotes longer lasting
engine life. However, rich operation results in high levels of HC, CO,
and PM emissions. Also, two-stroke engines tend to have high scavenging
losses, where up to a third of the unburned air and fuel mixture goes
out of the exhaust resulting in high levels of raw HC. Current average
snowmobile emission rates are 400 g/kW-hr (296 g/hp-hr) CO and 150 g/
kW-hr (111 g/hp-hr) HC. There are however, at least two snowmobile
models that use four-stroke engines. Two companies currently have a
moderate-powered four-stroke touring model that has very low emissions.
One sled uses a small advanced automotive engine, while the other uses
a modified ATV engine. Both engines are very sophisticated, using
electronic fuel injection and computer-based closed-loop control. The
other snowmobile manufacturers are planning to release four-stroke
models for the 2003 model year, but are focusing on higher performing
models that, according to

[[Page 68284]]

the manufacturers, may not have as good of emissions control as the
production four-stroke touring models.
b. What technology approaches are available to control emissions?
We believe the new emission standards are technologically feasible. A
variety of technologies are currently available or in stages of
development to be available for use on two-stroke snowmobiles. These
include improvements to carburetion (improved fuel control and
atomization, as well as improved production tolerances), enleanment
strategies for both carbureted and fuel injected engines, and semi-
direct and direct fuel injection. In addition to these two-stroke
technologies, converting to four-stroke engines is also feasible. Each
of these is discussed in the following paragraphs.
There are several ways to improve carburetion in snowmobile
engines. First, strategies to improve fuel atomization promote more
complete combustion of the fuel/air mixture. Additionally, improved
production tolerances enable more consistent fuel metering. Both of
these changes allow more accurate control of air-fuel ratios.
Snowmobile engines are currently calibrated with rich air-fuel ratios
for durability reasons. Leaner calibrations to CO and HC emissions pose
a challenge for maintaining engine durability, but many engine
improvements are available to prevent problems. These include changes
to the cylinder head, pistons, ports and pipes to reduce knock. In
addition critical engine components can be made more robust to improve
durability.
The same calibration changes to the air-fuel ratio just discussed
for carbureted engines can also be employed, possibly with more
accuracy, by using fuel injection. At least one major snowmobile
manufacturer currently employs electronic fuel injection on several of
its snowmobile models.
In addition to rich air-fuel ratios, one of the main reasons that
two-stroke engines have such high HC emission levels is that they
release a substantial amount of unburned fuel into the atmosphere as a
result from scavenging losses, as described above. One way to reduce or
eliminate such losses is to inject the fuel into the cylinder after the
exhaust port has closed. This can be done by injecting the fuel into
the cylinder through the transfer port (semi-direct injection) or
directly into the cylinder (direct injection). Both of these approaches
are currently being used successfully in two-stroke personal water
craft engines. We believe these technologies hold promise for
application to snowmobiles. In fact, one company is offering a
snowmobile with a semi-direct injection two-stroke engine for the 2003
model year. Manufacturers must address a variety of technical design
issues for adapting the technology to snowmobile operation, such as
operating in colder ambient temperatures and at variable altitude. The
averaging approach and the several years of lead time give
manufacturers time to incorporate these development efforts into their
overall research plan as they apply these technologies to snowmobiles.
In addition to the two-stroke technologies just discussed, using
four-stroke engines in snowmobiles is another feasible approach to
reduce emissions. Since they do not scavenge the exhaust gases with the
incoming air-fuel mixture, four-stroke engines have inherently lower HC
emissions compared to two-stroke engines. Four-stroke engines have a
lower power-to-displacement ratio than two-stroke engines and are
heavier. Thus, initially they may be more appropriate for snowmobile
models where extreme power and acceleration are not the primary selling
points. Such models include touring and sport trail sleds. However, one
company has developed a four-stroke engine based off one of their sport
highway motorcycle engines that produces 150 horsepower and will be
used in their high-performance snowmobiles in the 2003 model year.
c. What technologies are most likely to be used to meet emission
standards?
2006 Standards
We expect that, in the context of an emissions averaging program,
manufacturers might choose to take different paths to meet the 2006
emission standards. We expect manufacturers to use a mix of
technologies that will include improved carburetion and enleanment
strategies, combined with engine modifications, the use of direct
injection, and the use of four-stroke engine technology. For example,
depending on their emission rates, one scenario for meeting our
standards could be a mixture of 60 percent using improved carburetion,
enleanment strategies, and engine modifications, 15 percent using
direct injection, and another 15 percent using four-stroke engines.
Manufacturers can expect moderate emission reductions from engine
modifications and enleanment strategies. Most two-stroke snowmobile
engines are designed to operate with a rich air and fuel mixture, which
result in high levels of HC, CO, and PM. By reducing the amount of fuel
in the air and fuel mixture (i.e., enleanment), these emissions can be
reduced. Because manufacturers use the extra fuel in the air and fuel
mixture to help cool the engine, some modifications such as the use of
more robust materials, may be necessary. Manufacturers have indicated
to us that direct injection strategies can result in emission
reductions of 70 to 75 percent for HC and 50 to 70 percent for CO.
Certification results from 2000 model year outboard engines and
personal water craft (PWC) support such reductions. We believe that as
manufacturers learn to apply direct injection strategies they may
choose to implement those technologies on some of their more expensive
sleds and use less aggressive technologies, such as improved
carburetion and enleanment on their lower performance models.
It appears that the use of four-stroke engines in snowmobiles will
be more prevalent than we initially anticipated. For the 2003 model
year, all four of the major snowmobile manufacturers will offer a four-
stroke engine. Two manufacturers have already sold limited quantities
of their four-stroke snowmobiles in 2002. All of these engines will be
appearing in at least two different models and in some cases up to
three or four models. The size and design of these engines is quite
varied. All of the engines range in size from 650 cc to 1000 cc. There
are two cylinder and four cylinder engines, fuel injected and
carbureted, moderate horsepower and high horsepower. Manufacturers have
indicated that depending on their success, four-stroke engines will
play a large role in meeting our standards.
2010 Standards
As with the 2006 standards, we expect that manufacturers will use a
mix of technologies to meet our 2010 standards. To meet the 2010
standards, manufacturers will need to employ the use of advanced
technologies such as direct fuel-injection and four-stroke engines on a
larger portion of their production. As noted above, manufacturers are
beginning to introduce these technologies and will be gaining
experience with them over the next several years. Because we are
offering manufacturers the option to choose between two sets of
standards in 2010, the mixture of technologies will be very
manufacturer and engine family specific. For example, direct injection
typically reduces CO significantly but does not reduce HC to the same
extent as four-stroke engines. Engine families that manufacturers
believe will be most compatible with direct injection technology would
likely meet the 75 g/kW-hr HC and 200 g/kW-hr CO

[[Page 68285]]

standards. A potential scenario for meeting these standards could be a
mixture of 50 percent direct injection, 20 percent four-stroke engines,
and 30 percent with engine modifications. Engine families that
manufacturers believe will be more compatible with four-stroke
technology, which typically has superior HC emissions levels but do not
necessarily have exceptionally good CO performance, will likely meet
the 45 g/kW-hr HC and 275 g/kw-hr CO standards. Under either option, it
is possible that manufacturers will continue to sell two-stroke models
with lesser levels of technology. Manufacturers are likely to reduce
emissions where possible from at least a portion of the remaining two-
stroke engines through the use of engine modifications, calibration
optimization, and secondary air systems. In some cases this will be
necessary just to meet the FEL cap. A potential scenario for meeting
these standards could be a mixture of 70 percent four-stroke engines,
10 percent direct fuel injection, and 20 percent with engine
modifications.

IV. Permeation Emission Control

A. Overview

In the proposal we specified only exhaust emission controls for
recreational vehicles. However, several commenters raised the issue of
control of evaporative emissions related to permeation from fuel tanks
and fuel hoses. The commenters stated that work done by California ARB
on permeation emissions from plastic fuel tanks and rubber fuel line
hoses for various types of nonroad equipment as well as portable
plastic fuel containers raised a new emissions concern. Our own
investigation into the hydrocarbon emissions related to permeation of
fuel tanks and fuel hoses from recreational land-based and marine
applications supports the concerns raised by the commenters. Therefore,
on May 1, 2002, we reopened the comment period and requested comment on
possible approaches to regulating permeation emissions from
recreational vehicles. As a result of our investigations and the
comments received, we have determined that it is appropriate to
promulgate standards regulating permeation emissions from these
vehicles.
This section describes the provisions for 40 CFR part 1051, which
would apply only to recreational vehicle manufacturers. This section
also discusses test equipment and procedures (for anyone who tests fuel
tanks and hoses to show they meet emission standards) and general
compliance provisions.
We are adopting performance standards intended to reduce permeation
emissions from recreational vehicles. The standards, which apply to new
vehicles starting in 2008, are nominally based on manufacturers
reducing these permeation emissions from new vehicles by about 90
percent overall.\67\ We also recognize that there are many small
businesses that manufacture recreational vehicles. We are therefore
adopting several special compliance provisions to reduce the burden of
permeation emission regulations on small businesses. These special
provisions are the same as for the exhaust emission standards, as
applicable, and are discussed in Section III.E.
---------------------------------------------------------------------------

\67\ Estimated reductions in permeation are 95 percent when not
considering competition vehicles, which are exempt from the
standard.
---------------------------------------------------------------------------

B. Vehicles Covered by This Provision

We are adopting new permeation emission standards for new off-
highway motorcycles, all-terrain vehicles, and snowmobiles. These
provisions apply even if the recreational vehicle manufacturer
exercises the option to use an engine certified under another program
such as the small spark ignition requirements in 40 CFR part 90. These
standards would require these vehicle manufacturers to use low
permeability fuel tanks and hoses. We include vehicles and fuel systems
that are used in the United States, whether they are made domestically
or imported.
Even though snowmobiles do not usually experience year around use,
as is the case with ATVs and off-highway motorcycles, we are including
snowmobiles in this standard because it is common practice among
snowmobile owners to store their snowmobiles in the off-season with
fuel in the tank (typically half full to full tank). A fuel stabilizer
is typically added to the fuel to prevent gum, varnish, and rust from
occurring in the engine as a result of the fuel sitting in the fuel
tank and fuel system for an extended period of time; however, this does
not reduce permeation. Thus, snowmobiles experience fuel permeation
losses just like off-highway motorcycles and ATVs.
We are extending our basic nonroad exemptions to the engines and
vehicles covered by this rule. These include the testing exemption, the
manufacturer-owned exemption, the display exemption, and the national
security exemption. These exemptions are described in more detail under
Section VII.C. In addition, vehicles used solely for competition are
not considered to be nonroad vehicles, so they are exempt from meeting
the emission standards (but see discussion in Section III.C.1.a
regarding the voluntary program for certification of all off-highway
motorcycles).

C. Permeation Emission Standards

1. What Are the Emission Standards and Compliance Dates?
We are finalizing new standards that will require an 85-percent
reduction in plastic fuel tank permeation and a 95-percent reduction in
fuel system hose permeation from new recreational vehicles beginning in
2008. These standards and their implementation dates are presented in
Table IV.C-1. Section IV.D presents the test procedures associated with
these standards. Test temperatures are presented in Table IV.C-1
because they represent an important parameter in defining the emission
levels.
We will base the permeation standards on the inside surface areas
of the hoses and fuel tanks. We sought comment on whether the potential
permeation standards for fuel tanks should be expressed as grams per
gallon of fuel tank capacity per day or as grams per square meter of
inside surface area per day. Although volume is generally used to
characterize fuel tank emission rates, we base the standard on inside
surface area because permeation is a function of surface area. In
addition, the surface to volume ratio of a fuel tank changes with
capacity and geometry of the tank. Two similar shaped tanks of
different volumes or two different shaped tanks of the same volume
could have different g/gallon/day permeation rates even if they were
made of the same material and used the same emission-control
technology. Therefore, we believe that using a g/m\2\/day form of the
standard more accurately represents the emissions characteristics of a
fuel tank and minimizes complexity. This approach was supported by the
commenters.

[[Page 68286]]

Table IV.C-1.--Permeation Standards for Recreational Vehicles
----------------------------------------------------------------------------------------------------------------
Implementation
Emission component date Standard Test temperature
----------------------------------------------------------------------------------------------------------------
Fuel Tank Permeation................... 2008 1.5 g/m2/day............. 28 [deg]C (82 [deg]F)
Hose Permeation........................ 2008 15 g/m2/day.............. 23 [deg]C (73 [deg]F)
----------------------------------------------------------------------------------------------------------------

These standards are revised compared to the values we sought
comment on in the notice. In the reopening of the comment period, we
identified the need to accommodate variability and deterioration in
setting the fuel tank permeation standard. Since the notice, we have
received test information that suggests that a tank permeation standard
representing an 85 rather than a 95-percent reduction would fully
accommodate these factors. Nonetheless, we continue to believe that
manufacturers will target control technologies and strategies focused
on achieving reductions of 95 percent in production tanks. With regard
to the permeation standard for hoses, we have adjusted the standard
slightly to give the manufacturers more freedom in selecting their hose
material and to accommodate the fact that we selected a certification
test fuel based on a 10-percent ethanol blend, which would be prone to
greater permeation than straight gasoline.
Cost-effective technologies exist to significantly reduce
permeation emissions. Because essentially all of these vehicles use
high density polyethylene (HDPE) fuel tanks, manufacturers would be
able to choose from several technologies for providing a permeation
barrier in HDPE tanks. The use of metal fuel tanks would also meet the
standards, because metal tanks do not experience any permeation losses.
The hose permeation standard can be met using barrier hose technology
or through using low permeation automotive-type tubing. These
technologies are discussed in Section IV.F. The implementation dates
give manufacturers three to four years to comply. This will allow
manufacturers time to implement controls in their tanks and hoses in an
orderly business manner.
2. Will I Be Able to Average, Bank, or Trade Emissions Credits?
Averaging, banking, and trading (ABT) refers to the generation and
use of emission credits based on certified emission levels relative to
the standard. The general ABT concept is discussed in detail in Section
II.C.3. In many cases, an ABT program can improve technological
feasibility, provide manufacturers with additional product planning
flexibility, and reduce costs which allows us to consider emission
standards with the most appropriate level of stringency and lead time,
as well as providing an incentive for the early introduction of new
technology.
We are finalizing ABT for fuel tanks to facilitate the
implementation of the standard across a variety of tank designs which
include differences in wall thickness, tank geometry, material quality,
and pigment in plastic fuel tanks. To meet the standard on average,
manufacturers would be able to divide their fuel tanks into different
emission families and certify each of their emission families to a
different Family Emissions Level (FEL). The emission families would
include fuel tanks with similar characteristics, including wall
thickness, material used (including additives such as pigments,
plasticizers, and UV inhibitors), and the emission-control strategy
applied. The FELs would then be weighted by sales volume and fuel tank
inside surface area to determine the average level across a
manufacturer's total production. An additional benefit of a corporate-
average approach is that it provides an incentive for developing new
technology that can be used to achieve even larger emission reductions
or perhaps to achieve the same reduction at lower costs or to achieve
some reductions early.
Any manufacturer could choose to certify each of its evaporative
emission control families at levels which would meet the standard. Some
manufacturers may choose this approach as the could see it as less
complicated to implement.
We are also finalizing a voluntary program intended to give an
opportunity for manufacturers to prove out technologies earlier than
2008. Manufacturers will be able to use permeation control strategies
early, and even if they do not meet the standard, they can earn credit
through partial emission reduction that will give them more lead time
to meet the standard. This program will allow a manufacturer to certify
fuel tanks early to a less stringent standard and thereby delay the
fuel tank permeation standard. Therefore, a manufacturer can earn more
time to meet the 1.5 g/m\2\/day standard if they have an alternative
approach that will reduce permeation by a lesser amount earlier than
2008. Specifically, if a manufacturer certifies fuel tanks early to a
standard of 3.0 g/m\2\/day, they can delay the 1.5 g/m\2\/day standard
for these fuel tanks by 1 tank-year for every tank-year of early
certification. As an alternative, this delay could be applied to other
fuel tanks provided that these tanks have an equal or smaller inside
surface area and meet a level of 3.0 g/m\2\/day. As an example, suppose
a manufacturer were to sell 50 vehicles in 2006 and 75 vehicles in 2007
with fuel tanks that meet a level of 3.0 g/m\2\/day. This manufacturer
would then be able to sell 125 vehicles with fuel tanks that meet a
level of 3.0 g/m\2\/day in 2008 and later years. No uncontrolled tanks
could be sold after 2007. In addition to providing implementation
flexibility to manufacturers, this option, if used, would result in
additional and earlier emission reductions.
For hoses, we do not believe that ABT provisions would result in a
significant technological benefit to manufacturers. We believe that all
fuel hoses can meet the permeation standards using straight forward
technology as discussed in Section IV.F. From EPA's perspective,
including an ABT program in the rule creates a long-term administrative
burden that is not worth taking on since it does not provide the
industry with useful flexibility.
3. How Do I Certify My Products?
We are finalizing a certification process similar to our existing
program for other mobile sources. Manufacturers test representative
prototype designs and submit the emission data along with other
information to EPA in an application for a Certificate of Conformity.
As discussed in Section IV.D.3, we will allow manufacturers to certify
based on either design (for which there is already data) or by
conducting its own emissions testing. If we approve the application,
then the manufacturer's Certificate of Conformity allows the
manufacturer to produce and sell the vehicles described in the
application in the U.S.
Manufacturers certify their fuel systems by grouping them into
emission families that have similar emission characteristics. The
emission family definition is fundamental to the certification process
and to a large

[[Page 68287]]

degree determines the amount of testing required for certification. The
regulations include specific characteristics for grouping emission
families for each category of tanks and hoses. For fuel tanks, key
parameters include wall thickness, material used (including additives
such as pigments, plasticizers, and UV inhibitors), and the emission-
control strategy applied. For hoses, key parameters include material,
wall thickness, and emission-control strategy applied. To address a
manufacturer's unique product mix, we may approve using broader or
narrower engine families. The certification process for vehicle
permeation is similar as for the process for certifying engines (see
Section II.C.1).
4. What Durability Provisions Apply?
We are adopting several additional provisions to ensure that
emission controls will be effective throughout the life of the vehicle.
This section discusses these provisions for permeation from
recreational vehicles. More general certification and compliance
provisions, which apply across different vehicle categories, are
discussed in Sections II and VII, respectively.
a. How long do my vehicles have to comply? Manufacturers would be
required to build fuel systems that meet the emission standards over
each vehicle's useful life. For the permeation standards, we use the
same useful life as discussed in Section III.C.4.a for exhaust
emissions from recreational vehicle engines based on the belief that
fuel system components and engines are intended to have the same design
life. Further, we are applying the same warranty period for permeation
emission related components of the fuel system as for exhaust emission-
related components of the vehicle (See Section III.C.4.b).
b. How do I demonstrate emission durability? We are adopting
several additional provisions to ensure that emission controls will be
effective throughout the life of the vehicle. Vehicle manufacturers
must demonstrate that the permeation emission-control strategies will
last for the useful life of the vehicle. Any deterioration in
performance would have to be included in the family emissions limit.
This section discusses durability provisions for fuel tanks and hoses.
For plastic fuel tanks, we are specifying a preconditioning and
four durability steps that must be performed in conjunction with the
permeation testing for certification to the standard. These steps,
which include fuel soaking, slosh, pressure-vacuum cycling, temperature
cycling, and ultra-violet light exposure, are described in more detail
in Section IV.D.1. The purpose of these preconditioning steps is to
help demonstrate the durability of the fuel tank permeation control
under conditions that may occur in use. For fuel hoses, the only
preconditioning step that we are requiring is a fuel soak to ensure
that the permeation rate is stabilized prior to testing. Data from
before and after the durability tests would be used to determine
deterioration factors for the certified fuel tanks. The durability
factors would be applied to permeation test results to determine the
certification emission level of the fuel tank at full useful life. The
manufacturer would still be responsible for ensuring that the fuel tank
and hose meet the permeation standards throughout the useful life of
the vehicle.
We recognize that vehicle manufacturers will likely depend on
suppliers/vendors for treated tanks and fuel hoses. We believe that, in
addition to normal business practices, our testing requirements will
help assure that suppliers/vendors consistently meet the performance
specifications laid out in the certificate.

D. Testing Requirements

To obtain a certificate allowing sale of products meeting EPA
emission standards, manufacturers generally must show compliance with
such standards through emission testing. The test procedures for
determining permeation emissions from fuel tanks and hoses on
recreational vehicles are described below. This section also discusses
design-based certification as an alternative to performing specific
testing.
1. What Are the Test Procedures for Measuring Permeation Emissions From
Fuel Tanks?
Prior to testing the fuel tanks for permeation emissions, the fuel
tank must be preconditioned by allowing the tank to sit with fuel in it
until the hydrocarbon permeation rate has stabilized. Under this step,
the fuel tank must be filled with a 10-percent ethanol blend in
gasoline (E10), sealed, and soaked for 20 weeks at a temperature of 28
+/- 5[deg]C. Once the soak period has ended, the fuel tank is drained,
refilled with fresh fuel, and sealed. The permeation rate from fuel
tanks is measured at a temperature of 28 +/- 2[deg]C over a period of
at least 2 weeks. Consistent with good engineering judgment, a longer
period may be necessary for an accurate measurement for fuel tanks with
low permeation rates. Permeation loss is determined by measuring the
weight of the fuel tank before and after testing and taking the
difference. Once the mass change is determined it is divided by the
manufacturer provided tank surface area and the number of days of soak
to get the emission rate. As an option, permeation may be measured
using alternative methods that will provide equivalent or better
accuracy. Such methods include enclosure testing as described in 40 CFR
part 86. The fuel used for this testing will be a blend of 90-percent
gasoline and 10-percent ethanol. This fuel is consistent with the test
fuel used for highway evaporative emission testing.
To determine permeation emission deterioration factor, we are
specifying three durability tests: slosh testing, pressure-vacuum
cycling, and ultra-violet exposure. The purpose of these deterioration
tests is to help ensure that the technology is durable and the measured
emissions are representative of in-use permeation rates. For slosh
testing, the fuel tank is filled to 40-percent capacity with E10 fuel
and rocked for 1 million cycles. The pressure-vacuum testing contains
10,000 cycles from -0.5 to 2.0 psi. These two durability tests are
based on draft recommended SAE practice.\68\ The third durability test
is intended to assess potential impacts of UV sunlight (0.2 [mu]m--0.4
[mu]m) on the durability of the surface treatment. In this test, the
tank must be exposed to a UV light of at least 0.40 W-hr/m2 /min on the
tank surface for 15 hours per day for 30 days. Alternatively, it can be
exposed to direct natural sunlight for an equivalent period of time.
---------------------------------------------------------------------------

\68\ Draft SAE Information Report J1769, ``Test Protocol for
Evaluation of Long Term Permeation Barrier Durability on Non-
Metallic Fuel Tanks,'' (Docket A-2000-01, document IV-A-24).
---------------------------------------------------------------------------

We originally sought comment on applying the procedures in 49 CFR
part 173, appendix B, but upon further evaluation and receipt of
additional information found these inadequate for our purposes. The 49
CFR part 173 test procedure is designed for testing plastic receptacles
for transporting hazardous chemicals. This test focus on temperatures
and durability procedures that do not represent recreational vehicle
use.
2. What Are the Test Procedures for Measuring Permeation Emissions From
Fuel System Hoses?
The permeation rate of fuel from hoses would be measured at a
temperature of 23 +/- 2[deg]C using SAE

[[Page 68288]]

method J30\69\ with E10. The hose must be preconditioned with a fuel
soak to ensure that the permeation rate has stabilized. The fuel to be
used for this testing would be a blend of 90-percent gasoline and 10-
percent ethanol. This fuel is consistent with the test fuel used for
highway evaporative emission testing. Alternatively, for purposes of
submission of data at certification, permeation could be measured using
alternative equipment and procedures that provide equivalent results.
To use these alternative methods, manufacturers would have to apply to
us and demonstrate equivalence. Examples of alternative approaches that
we anticipate manufacturers may use are the recirculation technique
described in SAE J1737,\70\ enclosure-type testing such as in 40 CFR
part 86, or weight loss testing such as described in SAE J1527.\71\
---------------------------------------------------------------------------

\69\ SAE Recommended Practice J30, ``Fuel and Oil Hoses,'' June
1998, (Docket A-2000-01, document IV-A-92).
\70\ SAE Recommended Practice J1737, ``Test Procedure to
Determine the Hydrocarbon Losses from Fuel Tubes, Hoses, Fittings,
and Fuel Line Assemblies by Recirculation,''1997, (Docket A-2000-01,
document, IV-A-34).
\71\ SAE Recommended Practice J1527, ``Marine Fuel Hoses,''1993,
(Docket A-2000-01, document IV-A-19).
---------------------------------------------------------------------------

3. Can I Certify Based on Engineering Design Rather Than Through
Testing?
In general, test data would be required to certify fuel tanks and
hoses to the permeation standards. Test data could be carried over from
year to year for a given emission-control design. We do not believe the
cost of testing tanks and hose designs for permeation would be
burdensome especially given that the data could be carried over from
year to year, and that there is a good possibility that the broad
emission family concepts would lead to minimum testing. However, there
are some specific cases where we would allow certification based on
design. These special cases are discussed below.
We would consider a metal fuel tank to meet the design criteria for
a low permeation fuel tank because fuel does not permeate through
metal. However, we would not consider this design to be any more
effective than any other low permeation fuel tank for the purposes of
any sort of credit program. Although metal is impermeable, seals and
gaskets used on the fuel tank may not be. The design criteria for the
seals and gaskets would be that either they would not have a total
exposed surface area exceeding 1000 mm\2\, or the seals and gaskets
would have to be made of a material with a permeation rate of 10 g/
m\2\/day or less at 23[deg]C as measured under ASTM D814.\72\ A metal
fuel tank with seals that meet this design criteria would readily pass
the standard.
---------------------------------------------------------------------------

\72\ ASTM Standard Test Method D 814-95 (Reapproved 2000),
``Rubber Property--Vapor Transmission of Volatile Liquids,'' (Docket
A-2000-01, document IV-A-95).
---------------------------------------------------------------------------

Fuel hoses can be certified by design as being manufactured in
compliance with certain accepted SAE specifications. Specifically, a
fuel hose meeting the SAE J30 R11-A or R12 requirements could be
design-certified to the standard. In addition, fuel line meeting the
SAE J2260\73\ Category 1 requirements could be design-certified to the
standard. These fuel hoses and fuel line specifications are based on
15-percent methanol fuel and higher temperatures. We believe that fuel
hoses and lines that are tested and meet these requirements would also
meet our hose permeation standards because both are generally
acknowledged as representing more stringent test parameters. In the
future, if new SAE specifications are developed which are consistent
with our hose permeation standards, we would consider including hoses
meeting the new SAE requirements as being able to certify by design.
---------------------------------------------------------------------------

\73\ SAE Recommended Practice J2260, ``Nonmetallic Fuel System
Tubing with One or More Layers,''1996, (Docket A-2000-01, document
IV-A-18).
---------------------------------------------------------------------------

At certification, manufacturers will have to submit an engineering
analysis showing that the tank or hose designs will meet the standards
throughout their full useful life. The tanks and hoses will remain
subject to the emission standards throughout their useful lives. The
design criteria relate only to the issuance of a certificate.

E. Special Compliance Provisions

We believe that the permeation control requirements will be
relatively easy for small businesses to meet, given the relatively low
cost of the requirements and the availability of materials and
treatment support by outside vendors. Low permeation fuel hoses are
available from vendors today, and we would expect that surface
treatment would be applied through an outside company. However, to
minimize any additional burden these requirements may impose on small
manufacturers, we are implementing, where they are applicable to
permeation, the same options we proposed for the exhaust emission
standards. These options for small recreational vehicle manufacturers
are described in detail in Section III.E.

F. Technological Feasibility

We believe there are several strategies that manufacturers can use
to meet our permeation emission standards. This section gives an
overview of this technology. See Chapters 3 and 4 of the Final
Regulatory Support Document for more detail on the technology discussed
here.
1. Implementation Schedule
The permeation emission standards for fuel tanks become effective
in the 2008 model year. Several technologies are available that could
be used to meet this standard. Surface treatments to reduce tank
permeation are widely used today in other container applications, and
the technology and production facilities needed to conduct this process
exist. Selar is used by at least one portable fuel tank manufacturer
and has also been used in automotive applications. Plastic tanks with
coextruded barriers have been used in automotive applications for
years. However, fuel tanks used in recreational vehicles are primarily
(but not exclusively) high-density polyethylene tanks with no
permeation control. We received comments from manufacturers that they
would not be able to comply with permeation standards until 2008 or
2009. They stated that, especially for fuel tanks, they would need this
extra lead time to ensure that the useful life requirement can be met
on their products. At the same time, others commented that the
technology is already available and that the permeation standards
should apply in 2004. We believe it is appropriate to give
manufacturers until the 2008 model year for the fuel tank permeation
standards. Manufacturers will need lead time to allow for durability
testing and other development work associated with applying this
technology to recreational vehicles. This is especially true for
manufacturers or vendors who choose to set up their own sulfonation or
fluorination facilities in-house.
We believe that the low permeation hose technology can also be
applied in the 2008 time frame. A lower permeation fuel hose exists
today known as the SAE R9 hose that is as flexible as the SAE R7 hose
used in most recreational applications today. These SAE hose
specifications are contained in SAE J30 cited above. This hose would
meet our permeation standard on gasoline, but probably not on a 10-
percent ethanol blend. As noted in Chapter 4 of the Final Regulatory
Support Document, barrier materials typically used in R9 hose today may
have permeation rates 3 to 5 times

[[Page 68289]]

higher on a 10-percent ethanol blend than on straight gasoline.
However, there are several lower permeability barrier materials that
can be used in rubber hose that will comply with the hose permeation
requirement on a 10-percent ethanol blend and still be flexible enough
for use in recreational vehicles. This hose is available for automotive
applications at this time, but some lead time may be required to apply
these hoses to recreational vehicles if hose connection fitting changes
were required. For these reasons, we are implementing the hose
permeation standard on the same schedule as the tank permeation
standards.
2. Standard Levels
We have identified several strategies for reducing permeation
emissions from fuel tanks and hoses. We recognize that some of these
technologies may be more desirable than others for some manufacturers,
and we recognize that different strategies for equal emission
reductions may be better for different applications. A specific example
of technology that could be used to meet the fuel tank permeations
would be surface barrier treatments such as sulfonation or
fluorination. With these surface treatments, more than a 95-percent
reduction in permeation emissions from new fuel tanks is feasible.
However, variation in material tolerances and in-use deterioration can
reduce this effectiveness. Given the lead time for the standards,
manufacturers will be able to provide fuel tanks with consistent
material quality, and the surface treatment processes can be optimized
for a wide range of material qualities and additives such as pigments,
plasticizers, and UV inhibitors. We do not expect a large deterioration
in use; however, data on slosh testing suggest that some deterioration
may occur. To accommodate variability and deterioration, we are
finalizing a standard that represents about an 85-percent reduction in
permeation emissions from plastic fuel tanks. It is our expectation
that manufacturers will aim for a surface treatment effectiveness rate
as near to 100 percent a practical for new tanks. Therefore, even with
variability and deterioration in use, control rates are likely to
exceed 85 percent. Several materials are available today that could be
used as a low permeation barrier in rubber hoses. We present more
detail on these and other technological approaches below.
3. Technological Approaches
a. Fuel tanks. Blow molding is widely used for the manufacture of
small fuel tanks of recreational vehicles. Typically, blow molding is
performed by creating a hollow tube, known as a parison, by pushing
high-density polyethylene (HDPE) through an extruder with a screw. The
parison is then pinched in a mold and inflated with an inert gas. In
highway applications, non-permeable plastic fuel tanks are produced by
blow molding a layer of ethylene vinyl alcohol (EVOH) or nylon between
two layers of polyethylene. This process is called coextrusion and
requires at least five layers: the barrier layer, adhesive layers on
either side of the barrier layer, and HDPE as the outside layers which
make up most of the thickness of the fuel tank walls. However, multi-
layer construction requires two additional extruder screws which
significantly increases the cost of the blow molding process. Multi-
layer fuel tanks can also be formed using injection molding. In this
method, a low viscosity polymer is forced into a thin mold to create
each side of the fuel tank. The two sides are then welded together. To
add a barrier layer, a thin sheet of the barrier material is placed
inside the mold prior to injection of the poleythylene. The
polyethylene, which generally has a much lower melting point than the
barrier material, bonds with the barrier material to create a shell
with an inner liner.
A less expensive alternative to coextrusion is to blend a low
permeable resin in with the HDPE and extrude it with a single screw.
The trade name typically used for this permeation control strategy is
Selar. The low permeability resin, typically EVOH or nylon, creates
non-continuous platelets in the HDPE fuel tank which reduce permeation
by creating long, tortuous pathways that the hydrocarbon molecules must
navigate to pass through the fuel tank walls. Although the barrier is
not continuous, this strategy can still achieve greater than a 90-
percent reduction in permeation of gasoline. EVOH has much higher
permeation resistance to alcohol than nylon; therefore, it would be the
preferred material to use for meeting our standard which is based on
testing with a 10-percent ethanol fuel.
Another type of low permeation technology for fuel tanks would be
to treat the surfaces of a plastic fuel tanks with a barrier layer. Two
ways of achieving this are known as fluorination and sulfonation. The
fluorination process causes a chemical reaction where exposed hydrogen
atoms are replaced by larger fluorine atoms which creates a barrier on
the surface of the fuel tank. In this process, a batch of fuel tanks
are generally processed post production by stacking them in a steel
container. The container is then voided of air and flooded with
fluorine gas. By pulling a vacuum in the container, the fluorine gas is
forced into every crevice in the fuel tanks. As a result of this
process, both the inside and outside surfaces of the fuel tank would be
treated. As an alternative, fuel tanks can be fluorinated on-line by
exposing the inside surface of the fuel tank to fluorine during the
blow molding process. However, this method may not prove as effective
as off-line fluorination which treats the inside and outside surfaces.
Sulfonation is another surface treatment technology where sulfur
trioxide is used to create the barrier by reacting with the exposed
polyethylene to form sulfonic acid groups on the surface. Current
practices for sulfonation are to place fuel tanks on a small assembly
line and expose the inner surfaces to sulfur trioxide, then rinse with
a neutralizing agent. However, sulfonation can also be performed using
a batch method. Either of these processes can be used to reduce
gasoline permeation by more than 95 percent.
Over the first month or so of use, polyethylene fuel tanks can
expand by as much as three percent due to saturation of the plastic
with fuel. Manufacturers have raised the concern that this hydrocarbon
expansion could affect the effectiveness of surface treatments like
fluorination or sulfonation. We believe this will not have a
significant effect on the effectiveness of these surface treatments.
California ARB has performed extensive permeation testing on portable
fuel containers with and without these surface treatments. Prior to the
permeation testing, the tanks were prepared by first performing a
durability procedure where the fuel container is cycled a minimum of
1000 times between -1 psi and 5 psi. In addition, the fuel containers
are soaked with fuel for a minimum of four weeks prior to testing.
Their test data, presented in Chapter 4 of the Final Regulatory Support
Document show that fluorination and sulfonation are still effective
after this durability testing.
Manufacturers have also commented that fuel sloshing in the fuel
tank, under normal in-use operation, could wear off the surface
treatments. However, we do not believe that this is likely. These
surface treatments actually result in an atomic change in the structure
of the

[[Page 68290]]

outside surface of the fuel tank. To wear off the treatment, the
plastic would need to be worn away on the outside surface. In addition,
testing by California ARB shows that the fuel tank permeation standard
can be met by fuel tanks that have been sloshed for 1.2 million cycles.
Test data on an sulfonated automotive HDPE fuel tank after five years
of use showed no deterioration in the permeation barrier. This data are
presented in Chapter 4 of the Final Regulatory Support Document.
Permeation can also be reduced from fuel tanks by constructing them
out of a lower permeation material than HDPE. For instance, metal fuel
tanks would not permeate. In addition, there are grades of plastics
other than HDPE that could be molded into fuel tanks. One commenter
suggested nylon; however, although nylon has excellent permeation
resistance on gasoline, it has poor chemical resistance to alcohol-
blended fuels. Other materials, which have excellent permeation even
with alcohol-blended fuels are acetal copolymers and thermoplastic
polyesters. At this time, these materials are generally much more
expensive than HDPE.
b. Hoses. Fuel hoses produced for use in recreational vehicles are
generally extruded nitrile rubber with a cover for abrasion resistance.
Lower permeability fuel hoses produced today for other applications are
generally constructed in one of two ways: either with a low
permeability layer or by using a low permeability rubber blend. By
using hose with a low permeation thermoplastic layer, permeation
emissions can be reduced by more than 95 percent. Because the
thermoplastic layer is very thin, on the order of 0.1 to 0.2 mm, the
rubber hose retains its flexibility. Two thermoplastics which have
excellent permeation resistance, even with an alcohol-blend fuel, are
ETFE and THV.\74\
---------------------------------------------------------------------------

\74\ ethylene-tetrafluoro-ethylene (ETFE), tetra-fluoro-
ethylene, hexa-fluoro-propylene, and vinyledene fluoride (THV).
---------------------------------------------------------------------------

In automotive applications, multilayer plastic tubing, made of
fluoropolymers is generally used. An added benefit of these low
permeability lines is that some fluoropolymers can be made to conduct
electricity and therefore can prevent the buildup of static charges.
Although this technology can achieve more than an order of magnitude
lower permeation than barrier hoses, it is relatively inflexible and
may need to be molded in specific shapes for each recreational vehicle
design. Manufacturers have commented that they would need flexible hose
to fit their many designs, resist vibration, and to simplify the hose
connections and fittings.
An alternative approach to reducing the permeability of fuel hoses
would be to apply a surface treatment such as fluorination or
sulfonation. This process would be performed in a manner similar to
discussed above for fuel tanks.
4. Conclusions
The standards for permeation emissions from recreational vehicles
reasonably reflect what manufacturers can achieve through the
application of available technology. Manufacturers will have several
years of lead time to select, design, and produce permeation emission-
control strategies that will work best for their product lines. We
expect that meeting these requirements will pose a challenge, but one
that is feasible taking into consideration the availability and cost of
technology, lead time, noise, energy, and safety. The role of these
factors is presented in detail in Chapters 3 and 4 of the Final
Regulatory Support Document.
The permeation standards are based on the effective application of
low permeable materials or surface treatments. This is a step change in
technology; therefore, we believe that even if we set a less stringent
permeation standard, these technology options would likely still be
used. In addition, this technology is relatively inexpensive and can
achieve meaningful emission reductions. The standards are expected to
achieve more than an 85-percent reduction in permeation emissions from
fuel tanks and more than 95 percent from hoses. We believe that more
stringent standards could result in significantly more expensive
materials without corresponding additional emission reduction. In
addition, the control technology would generally pay for itself over
time by conserving fuel that would otherwise evaporate. The projected
costs and fuel savings are discussed in Chapter 5 of the Final
Regulatory Support Document.

V. Large Spark-Ignition (SI) Engines

A. Overview

This section applies to most nonroad spark-ignition engines rated
over 19 kW (``Large SI engines''). The emission standards will lead to
emission reductions of about 90 percent for CO, NO_X, and 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 help reduce ozone and CO concentrations and will also be
valuable to individuals operating these engines in areas with limited
fresh air circulation. 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, as described in the Final Regulatory Support Document.
This section describes the requirements that apply to engine
manufacturers. See Section II for a description of our general approach
to regulating nonroad engines and how manufacturers show that they meet
emission standards. See Section VII for additional requirements for
engine manufacturers, equipment manufacturers, and others. See Section
VIII for general provisions related to testing equipment and
procedures.

B. Large SI Engines Covered by This Rule

Large SI engines covered in this section power nonroad equipment
such as forklifts, sweepers, pumps, and generators. This includes
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.
This final rule applies only to spark-ignition engines. Our most
recent rulemaking for nonroad diesel engines adopted a definition of
``compression-ignition'' that addressed the status of alternative-fuel
engines (63 FR 56968, October 23, 1998). We are adopting 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.\75\ These
new definitions apply to 40 CFR parts 89 and 1048. Spark-ignitions
include gasoline-fueled engines and any others that control power with
a throttle and follow the theoretical Otto cycle. Compression-ignition
engines are any reciprocating internal-combustion engines that are not
spark-ignition engines. Under these definitions, it is possible for a
diesel-derived engine to fall under the spark-ignition program. We
believe the requirements adopted in this rule are feasible and
appropriate for these engines. However, we will allow such engines over
250 kW to instead meet the requirements that apply to nonroad

[[Continued on page 68291]]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]
]

[[pp. 68291-68340]]
Control of Emissions From Nonroad Large Spark-Ignition Engines,
and Recreational Engines (Marine and Land-Based)

[[Continued from page 68290]]

[[Page 68291]]

diesel engines. We believe this is appropriate for several reasons.
First, the technology requirements are comparable between programs. The
nonroad diesel emission standards, which apply over the longer useful
life characteristic of diesel engines, are slightly more stringent for
CO and slightly less stringent for HC+NO_X. The calibration
changes needed to adjust these emission levels are not fundamental to
the overall design of the emission-control system. Second, the diesel
engine manufacturers producing these engines are already set up to do
testing based on test procedures that apply to diesel engines. To the
extent that they would incur costs to be able to run test procedures
specified for Large SI engines, these costs would likely not correspond
with improving emission-controls. Third, these engines share important
technical characteristics with diesel engines and are likely to
experience in-use operation that is more like that of nonroad diesel
engines. In addition, they are installed in applications that also use
diesel engines, not Large SI engines.
---------------------------------------------------------------------------

\75\ Gas turbines are non-reciprocating internal combustion
engines.
---------------------------------------------------------------------------

Several types of engines are excluded or exempted from these new
regulations. 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, stationary-source engines are
not nonroad engines, so the emission standards don't apply to engines
used in stationary applications. In general, an engine that would
otherwise be considered a Large SI engine is not considered a nonroad
engine if it will be either installed in a fixed position or if it will
be a portable (or transportable) engine operating for at least one-year
periods without moving throughout its lifetime. We are adopting the
same definitions for these engines that have already been established
for other programs. These stationary engines (that would otherwise
qualify as Large SI engines) must have an engine label identifying
their excluded status. This is especially valuable for importing
excluded engines without complication from U.S. Customs officials. It
also helps us ensure that such engines are legitimately excluded from
emission standards.
2. Exclusion for Engines Used Solely for Competition
For Large SI engines we proposed the existing regulatory definition
for nonroad engines, with excludes engines used solely for competition.
As described in the proposed rule, we are not aware of any
manufacturers producing new engines that are intended only for
competition. As a result, we are not adopting any specific provisions
addressing a competition exclusion for manufacturers. Part 1068 of the
regulations includes provisions addressing the practice of modifying
certified engines for competition (see Section VII.C).
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 are therefore adopting an
exemption from the Large SI standards in 40 CFR part 1048 for engines
that are already certified to the emission standards in 40 CFR part 86
for highway applications. To qualify for this exemption from separately
certifying to nonroad standards, the manufacturer must makes no changes
to the engine that might affect its exhaust or evaporative emissions.
Companies using this exemption must report annually to us, including a
list of its exempted engine models. For engines included under this
provision, manufacturers of the vehicle or engine 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 regulations
describes the qualifying criteria and responsibilities in greater
detail.
We generally prohibit equipment or vehicle manufacturers from
producing new nonroad equipment that does not have engines certified to
nonroad emission standards. However, in some cases a manufacturer may
want to produce vehicles certified to highway emission standards for
nonroad use. We are providing an exemption for these manufacturers, as
long as there is no change in the vehicle's exhaust or evaporative
emission-control systems. For example, a mining company may want to use
a pickup truck for dedicated work at a mine site, but special-order the
trucks from the manufacturer with modifications that cause the truck to
no longer qualify as a motor vehicle. Manufacturers may produce such a
modified version of a truck that has been certified to the motor-
vehicle standards, as long as the modifications don't affect its
emissions.
4. Lawn and Garden Engine Exemption
Most Large SI engines, rated over 19 kW, 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, 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). We
are not changing this provision, and engines so certified would not be
subject to the requirements that apply to Large SI engines. This
approach allows 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 is also
consistent with the provisions adopted by California ARB, except for
the addition of the 30-kW cap to prevent treating high-power engines
under the program that applies to lawn and garden engines.
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 nonroad spark-ignition engines below 19 kW. This rule
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), manufacturers may certify any
engine rated under 19 kW to the more stringent Large SI emission
standards. Such an engine is then exempt from the requirements of 40
CFR part 90.

C. Emission Standards

In October 1998, California ARB adopted emission standards for
Large SI engines. We are extending these requirements to the rest of
the U.S. in the near term. We are also revising the

[[Page 68292]]

emission standards and adding various provisions in the long term, as
described below. The near-term and the long-term emission standards are
based on three-way catalytic converters with electronic fueling systems
to control emissions, and differ primarily in terms of how well the
controls are optimized. In addition to the anticipated emission
reductions, we project that these technologies will provide large
savings to operators as a result of reduced fuel consumption and other
performance improvements.
An important element of the control program is the attempted
harmonization with the requirements adopted by California ARB. We are
aware that inconsistent or conflicting requirements may lead to
additional costs. Cooperation between agencies has allowed a great
degree of harmonization. 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
requirements in greater detail.
1. What Are the Emission Standards and Compliance Dates?
a. Exhaust emissions. We are adopting 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 4.0 g/kW-hr (3.0 g/hp-hr) for HC+NO_X
emissions and 50 g/kW-hr (37 g/hp-hr) for CO emissions. See Section V.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
are similar to those used for many years in highway applications, but
not necessarily with the same degree of sophistication.
Adopting emission standards for these engines starting in 2004
allows a relatively short lead time. However, 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. Adopting these near-term
emission standards allows us to set early requirements to introduce the
low-emission technologies for substantial emission reductions with
minimal lead time. The final requirements includes two principal
adjustments to align with the California ARB standards. First, we
specify that manufacturers' deterioration factors for 2004 through 2006
model years should be based on emission measurements over 3500 hours of
engine operation, rather than the full useful life of 5000 hours.
Second, for those same model years, we are applying an emission
standard of 5.4 g/kW-hr (4.0 g/hp-hr) HC+NO_X for any in-use
testing to account for the potential for additional deterioration
beyond 3500 hours. This allowance for higher in-use emissions is a
temporary provision to ensure the feasibility of compliance in the
early years of the program. Testing has shown that with additional
design time, manufacturers can incorporate emission-control
technologies with sufficient durability that the long-term standards do
not require a separate in-use standard. This is separate from the
field-testing standards described below.
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. We are therefore adopting a second tier of
standards to require additional emission reductions. These later
standards require manufacturers to control emissions under both steady-
state and transient engine operation, as described in Section V.D
below). Setting the emission standards to require additional control
involves separate consideration of the achievable level of control for
HC+NO_X and CO emissions. While HC+NO_X emissions
contribute to nonattainment of ozone air quality standards, CO
emissions contribute to nonattainment of CO air quality standards and
potentially harmful exposures of individuals where engines are
operating in areas where fresh airflow may be restricted. Emission-
control technology is able to simultaneously control these three
pollutants, but a tradeoff between NO_X and CO emissions
persists for any given system. This relationship is determined by an
engine's precise control of air-fuel ratios--shifting to air-fuel
ratios slightly lean of stoichiometric increases NO_X
emissions but decreases CO emissions and vice versa. Engines using
different fuels face this same situation, though gasoline engines
operating under heavy load generally need to shift to richer air-fuel
ratios to prevent accelerated engines wear from very high combustion
temperatures.
Our primary focus in setting the level of the emission standards is
reductions in emissions that contribute to ambient air-pollution
problems. At the same time, we recognize that these engines are used in
many applications where there are concerns about personal exposure to
the engine exhaust, including workplace exposure, focusing primarily on
CO exposure. It is appropriate to take such concerns into consideration
in setting the level of the standards. In this case, where the
equipment using these engines can vary substantially and where the
emission-control technology means there is a trade-off between
HC+NO_X control and CO control, it is difficult to set a
single, optimal standard for all three pollutants. In such a situation
it is reasonable to have more than one set of standards to allow an
engine to use technologies focused on controlling the pollutants of
most concern for a specific application.
We are not in a position, however, to readily identity the specific
levels of alternative standards that are appropriate for each
application or to pick specific applications that should go with
different standards. We also want to ensure that engines significantly
reduce emissions of all three pollutants.
To address this, we are setting a combination of standards
requiring more effective emission controls starting with the 2007 model
year. First, we are setting benchmark emission standards of 2.7 g/kW-hr
(2.0 g/hp-hr) for HC+NO_X emissions and 4.4 g/kW-hr (3.3 g/
hp-hr) for CO emissions. The emission standards apply to measurements
during duty-cycle testing under both steady-state and transient
operation, including certification, production-line testing, and in-use
testing.\76\ These emission levels provide for substantial control of
HC+NO_X emissions (in fact, these standards are more
stringent than those proposed), but also contain substantial control of
CO emissions to protect against individual exposure as well as CO
nonattainment.
---------------------------------------------------------------------------

\76\ See Section V.D for a discussion of duty cycles.
---------------------------------------------------------------------------

We are also including an option for manufacturers to certify their
engines to different emission levels to allow manufacturers to build
engines whose emission controls are more weighted toward controlling
NO_X emissions to reflect the inherent tradeoff of
NO_X and CO emissions. Generally this involves meeting a less
stringent CO standard if a manufacturer certifies an engine with lower
HC+NO_X emissions. Table V.C-1 shows several examples of
possible combinations of HC+NO_X and CO emission standards.
The highest allowable CO standard is 20.6 g/kW-hr (15.4 g/hp-hr), which
corresponds with HC+NO_X emissions below 0.8 g/kW-hr

[[Page 68293]]

(0.6 g/hp-hr). Manufacturers certify to any HC+NO_X level
between and including 0.8 and 2.7 g/kW-hr, rounding to the nearest 0.1
g/kW-hr. They will certify also to the corresponding CO level, as
calculated using the formula below, again rounding to the nearest 0.1
g/kW-hr.

Table V.C-1.--Samples of Possible Alternative Duty-Cycle Emission
Standards for Large SI Engines(g/kW-hr)*
------------------------------------------------------------------------
HC+NO_X CO
------------------------------------------------------------------------
2.7.......................................................... 4.4
2.2.......................................................... 5.6
1.7.......................................................... 7.9
1.3.......................................................... 11.1
1.0.......................................................... 15.5
0.8.......................................................... 20.6
------------------------------------------------------------------------
* As described in the Final Regulatory Support Document and the
regulations, the values in the table are related by the following
formula: (HC+NO_X) x CO0.784 = 8.57. These values follow directly from
the logarithmic relationship presented with the proposal in the Draft
Regulatory Support Document.

We believe this flexible approach to setting standards is the most
appropriate and efficient way to allocate the different design
strategies to achieve effective reductions of HC+NO_X
emissions while providing for the best control of CO emissions where it
is most needed. Testing has shown that emission controls are more
likely to experience degradation with respect to controlling CO
emissions than HC or NO_X emissions. Manufacturers therefore
have a natural incentive to certify engine families with an
HC+NO_X emission level as low as possible to increase the
compliance margin for meeting the CO standard. In addition, many of
these engines will be used in applications where ozone is of more
concern. As a result, we expect manufacturers to design most of their
engines to operate substantially below the 2.7 g/kW-hr standard for
HC+NO_X emissions. This approach also encourages
manufacturers to continually improve their control of HC+NO_X
emissions over time. At the same time, to the extent that purchasers
want engines with low CO emission levels, particularly for exposure-
related concerns, manufacturers will be able to produce compliant
engines that will provide appropriate protection. Note that engines
operating at the highest allowable CO emission levels under the 2007
standards will still be substantially reducing CO emissions compared
with baseline levels. The emission standards in this final rule will
achieve substantial reductions, but are not designed to guarantee
workplace safety or to set a safety standard. Rather, we intend to
facilitate the use of engine-based control technologies so that owners
and operators can purchase equipment to help them address these
concerns.
We are not adopting any controls or limits to restrict the sale of
engines meeting certain requirements into certain applications. We
believe that the manufacturers and customers for these products will
together make educated choices regarding the appropriate mix of
emission controls for each application and that market forces will
properly balance emission controls for the different pollutants in
specific applications. We believe that customers for these
applications, some of whom are subject to occupational air-quality
standards for related pollutant concentrations, will be well placed to
make informed choices regarding air-pollution control, especially given
their ability to make choices based on the specific environmental
circumstances of each particular customer.\77\
---------------------------------------------------------------------------

\77\ While the emission standards in this final rule require
substantial emission reductions of CO and other harmful pollutants
from nonroad engines, this does not replace the need for ongoing
regulation of air quality to protect occupational safety and health.
More specifically, in accordance with the limitations provided in
Section 310(a) of the Clean Air Act (42 U.S.C. section 7610(a)),
nothing in this rule affects the Occupational Safety and Health
Administration's authority to enforce standards and other
requirements under the Occupational Safety and Health Act of 1970
(29 U.S.C. sections 651 et seq.).
---------------------------------------------------------------------------

We are adopting field-testing standards of 3.8 g/kW-hr (2.8 g/hp-
hr) for HC+NO_X and 6.5 g/kW-hr (4.9 g/hp-hr) for CO. As
described above for duty-cycle testing, field-testing allows for the
same pattern of optional emission standards to reflect the tradeoff of
CO and NO_X emissions. See Section V.D.5 for more information
about field testing.
As described in Chapter 4 of the Final Regulatory Support Document,
we believe manufacturers can achieve these emission standards by
optimizing currently available three-way catalysts and electronically
controlled fuel systems.
Two additional provisions apply to specific situations. First, some
engines need to operate with rich air-fuel ratios at high loads to
protect the engine from overheating. This is especially true for
gasoline-fueled engines, which typically experience higher combustion
temperatures. When operating at such air-fuel ratios, the engines may
be unable to meet the CO emission standard during steady-state testing
because the steady-state duty cycle involves sustained operation under
high-load conditions, unlike the transient duty cycle. If a
manufacturer shows us that this type of engine operation keeps it from
meeting the CO emission standard shown above for specific models, we
will approve a separate CO emission standard of 31.0 g/kW-hr that would
apply only to steady-state testing. This standard reflects the
adjustment needed at high-load operation and would apply to any steady-
state tests for certification, production-line testing, or in-use
testing. To prevent high in-use emission levels, we are adopting
several additional provisions related to this separate CO standard.
Manufacturers must show that enrichment is necessary to protect the
engine from damage and that enrichment will be limited to operating
modes that require additional cooling to protect the engine from
damage. In addition, manufacturers must show in their application for
certification that enrichment will rarely occur in the equipment in
which your engines are installed (for example, an engine that is
expected to operate 5 percent of the time in use with enrichment would
clearly not qualify). Finally, manufacturers must include in the
emission-related installation instructions any steps necessary for
someone installing the engines to prevent enrichment during normal
operation. This option does not apply to transient or field testing, so
these engines would need to meet the same formula for HC+NO_X
and CO standards that apply to other engines for transient testing and
for field testing. By tying the CO standard for these engines to the
highest allowable CO emission level for field testing, we are
effectively requiring that manufacturers ensure that in-use engines
employ engine-protection strategies no more frequently than is
reflected in the steady-state duty cycles for certification.
Second, equipment manufacturers have made it clear that some
nonroad applications involve operation in severe environments that
require the use of air-cooled engines. These engines rely on air
movement instead of an automotive-style water-cooled radiator to
maintain acceptable engine temperatures. Since air cooling is less
effective, these engines rely substantially on enrichment to provide
additional cooling relative to water-cooled engines. At these richer
air-fuel ratios, catalysts are able to reduce NO_X emissions
but oxidation of CO emissions is much less effective. As a result, we
are adopting emission standards for these ``severe-duty'' engines of
2.7 g/kW-hr for HC+NO_X and 130 g/kW-hr for CO. These
standards apply to duty-cycle

[[Page 68294]]

emission testing for both steady-state and transient measurements (for
certification, production-line, and in-use testing). The corresponding
field-testing standards are 3.8 g/kW-hr for HC+NO_X and 200
g/kW-hr for CO. Severe-duty applications include concrete saws and
concrete pumps. These types of equipment are exposed to high levels of
concrete dust, which tends to form a thick insulating coat around any
heat-exchanger surfaces and exposes engines to highly abrasive dust
particles. Manufacturers may request approval in identifying additional
severe-duty applications subject to these less stringent standards if
they can provide clear evidence that the majority of installations need
air-cooled engines as a result of operation in a severe-duty
environment. This arrangement generally prevents these higher-emitting
engines from gaining a competitive advantage in markets that don't
already use air-cooled engines.
We believe 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 2004
emission standards should be capable of meeting the 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 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 V.D.5, since engines will not be
following a prescribed duty cycle.
For engines fueled by gasoline and liquefied petroleum gas (LPG),
we specify emission standards based on total hydrocarbon measurements,
while California ARB standards are based on nonmethane hydrocarbons. We
believe that switching to measurement based on total hydrocarbons
simplifies testing, especially for field testing of in-use engines with
portable devices (See Section V.D.5). To maintain consistency with
California ARB standards in the near term, we will allow manufacturers
to base their certification through 2006 on either nonmethane or total
hydrocarbons (see 40 CFR 1048.145). Methane emissions from controlled
engines operating on gasoline or LPG are about 0.1 g/kW-hr.
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 have
therefore specified nonmethane hydrocarbon emissions for comparison
with the standard for natural gas engines. However, the emission
standards based on measuring emissions in the field depend on total
hydrocarbons. We are therefore adopting a NO_X-only field-
testing standard for natural gas engines instead of a HC+NO_X
standard. Since control of NO_X emissions for natural gas
engines poses a significantly greater challenge than controlling
nonmethane hydrocarbons, duty-cycle testing provides adequate assurance
that these engines have sufficiently low hydrocarbon emission levels.
Manufacturers must show that they meet these duty-cycle standards for
certification and the engines remain subject to the nonmethane
hydrocarbon standard in-use when tested over the same duty-cycles.
b. Evaporative emissions. We are adopting requirements related to
evaporative and permeation emissions from gasoline-fueled Large SI
engines. For controlling diurnal emissions, we are adopting an emission
standard of 0.2 grams of hydrocarbon per gallon of fuel tank capacity
during a 24-hour period. In addition, we specify that manufacturers use
fuel lines meeting an industry standard for permeation-resistance.
Finally, we require that manufacturers take steps to prevent fuel from
boiling. We expect certification of manufacturers' equipment to be
design-based, as compared with conducting a full emission-measurement
program during certification. As such, meeting these evaporative
requirements is much more like meeting the requirements related to
controlling crankcase emissions and is therefore discussed in detail in
Section V.C.4 below.
2. May I Average, Bank, or Trade Emission Credits?
We are not including an averaging, banking, and trading program for
certifying engines. As described in Chapter 4 of the Final Regulatory
Support Document, we believe that manufacturers will generally be able
to rely on a relatively uniform application of emission-control
technology to meet emission standards. The standards were selected
based on the capabilities of all manufacturers to comply with all their
models without an emission-credit program. Moreover, overlaying an
emission-credit program on the flexible standards described above would
be highly impractical. If such a program could be devised it would need
to be very complex and would achieve little, if any, advantage to
manufacturers beyond the advantages already embodied in the flexible
approach we are adopting.
However, as an alternative to a program of calculating emission
credits for averaging, banking, and trading, we are adopting a simpler
approach of ``family banking'' to help manufacturers transition to new
emission standards (see 40 CFR 1048.145 of the regulations).
Manufacturers may certify an engine family early, which would allow
them to delay certification of smaller engine families. This would be
based on the actual sales of each engine family; this requires no
calculation or accounting of emission credits. The manufacturer would
have actual sales figures for the early family at the end of the
production year, which would yield a total number of allowable sales
for the engine family with delayed compliance. Manufacturers may
certify engines to the 2004 standards early, but this would provide
benefits only for complying with the 2004 standards. These ``credits''
would not apply to engines for meeting the 2007 standards.
3. Is EPA Adopting Voluntary Blue Sky Standards for These Engines?
We are adopting voluntary Blue Sky standards for Large SI engines.
We are setting a target of 0.8 g/kW-hr (0.6 g/hp-hr) HC+NO_X
and 4.4 g/kW-hr (3.3 g/hp-hr) CO as a qualifying level for Blue Sky
Series engines. The corresponding field-testing standards for Blue Sky
Series engines are 1.1 g/kW-hr (0.8 g/hp-hr) HC+NO_X and 6.6
g/kW-hr (4.9 g/hp-hr) CO. These voluntary standards are based on
achieving the maximum control of both HC+NO_X and CO
emissions, as described in Section V.C.1. To achieve these emission
levels, manufacturers will need to apply significantly additional
technology beyond that required for the mandatory standards.
Manufacturers may start producing engines to these voluntary
standards immediately after this final rule becomes effective. In
addition, we are adopting interim voluntary standards corresponding
with the introduction of new emission standards. Since manufacturers
will not be complying early to bank emission credits, voluntary
emission standards are an appropriate way to encourage manufacturers to
meet emission standards before the regulatory deadline. If
manufacturers certify engines to these voluntary standards, they are
not eligible for participation in the family-banking program described

[[Page 68295]]

above. In the 2003 model year, manufacturers may 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 are
available to customers outside of California desiring emission
reductions or fuel-economy improvements. Similarly, for 2003 through
2006 model years, manufacturers may certify their engines to the
requirements that start to apply in 2007.
4. 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 (mostly
hydrocarbons) can accumulate in the crankcase. These crankcase
emissions are significant, representing about 33 percent of total
exhaust hydrocarbon. Uncontrolled engines route these vapors directly
to the atmosphere. We have long required that automotive engines
prevent crankcase emissions. Manufacturers typically do this by routing
crankcase vapors through a valve into the engine's air intake system
where they are burned in the combustion process.
Manufacturers may choose one of two methods for controlling
crankcase emissions. First, adding positive-crankcase ventilation
prevents crankcase emissions. Since automotive engine blocks are
already tooled for closed crankcases, the cost of adding a valve for
positive-crankcase ventilation for most engines is very small. An
alternative method addresses specific concerns related to turbocharged
engines or engines operating in severe-duty environments. Where closed
crankcases are impractical, manufacturers may therefore measure
crankcase emissions during any emission testing to add crankcase
emissions to measured exhaust emissions for comparing with the
standards.
b. Diagnosing malfunctions. Manufacturers must design their Large
SI engines to 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.\78\ 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. We are not requiring similar
diagnostic controls for recreational vehicles or recreational marine
diesel engines, because the anticipated emission-control technologies
for these other applications are generally less susceptible to drift
and gradual deterioration.
---------------------------------------------------------------------------

\78\ Stoichiometry 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.
---------------------------------------------------------------------------

This diagnostic requirement focuses solely on maintaining
stoichiometric control of air-fuel ratios. This kind of design detects
problems such as broken oxygen sensors, leaking exhaust pipes, fuel
deposits, and other things that 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 the signaling of false failures as much as
possible. The diagnostic requirements in this rule therefore focus on
detecting inappropriate air-fuel ratios, which is the most likely
failure mode for three-way catalyst systems. The malfunction-indicator
light must go on when an engine runs for a full minute under closed-
loop operation without reaching a stoichiometric air-fuel ratio.
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 (with two-way catalysts) would not be as sensitive to air-
fuel ratio as with stoichiometric designs. For these or other engines
that rely on emission-control technologies incompatible with the
diagnostic system described above, manufacturers must devise an
alternate system that alerts the operator to engine malfunctions that
would prevent the emission-control system from functioning properly.
The automotive industry has developed a standardized protocol for
diagnostic systems, including hardware specifications, and uniform
trouble codes. In the regulations we reference standards adopted by the
International Organization for Standardization (ISO) for automotive
systems. If manufacturers find that these standards are not applicable
to the simpler diagnostic design specified 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. Manufacturers may request approval to use systems that don't
meet the automotive specifications if those specifications are not
practical or appropriate for their engines.
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. In 1998, 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.\79\

[[Page 68296]]

This study did not take into account the possibility of unusually high
fuel temperatures during engine operation, as described further below.
---------------------------------------------------------------------------

\79\ ''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 adopting basic measures to reduce evaporative emissions from
gasoline-fueled Large SI engines. First, we are adopting an evaporative
emission standard of 0.2 grams per gallon of fuel tank capacity for 24-
hour day when temperatures cycle between 72[deg]
and 96[deg]
F. For
purposes of certification, manufacturers may choose, however, to rely
on a specific design for certification instead of measuring emissions.
We have identified a technology that adequately prevents evaporative
emissions such that the design itself would be enough to show
compliance with the evaporative emission standard for purposes of
certification. Specifically, 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 3.5 psi or for vacuum pressures of at least
1.5 psi.\80\ We know that any Large SI engines or vehicles operating
with these pressures would meet the standard because test data confirm
the basic chemistry principles related to phase-change pressure
relationships showing that fuel tanks will remain sealed at all times
during the prescribed test procedure. Also, similar to the Underwriters
Laboratories' requirement, we specify 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.
---------------------------------------------------------------------------

\80\ ''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.I for our
consideration of incorporating the UL requirements into our
regulations by reference.
---------------------------------------------------------------------------

In some applications, manufacturers may want to avoid high fuel-
tank pressures. Manufacturers may be able to meet the standard using an
air bladder inside the fuel tank that changes in volume to keep the
system in equilibrium at atmospheric pressure.\81\ We have data showing
that these systems also would remain sealed at all times during the
prescribed test procedure. However, the permeation levels related to
the air bladder and the long-term durability of this type of system are
still unknown. Once these parameters are established with test data,
perhaps with some additional product development, this technology may
then qualify as an option for design-based certification. Similarly,
collapsible bladder tanks, which change in volume to prevent generation
of a vapor space or vapor emissions, may eventually be available as a
technology for design-based certification once permeation data are
available to confirm that systems with these tanks would meet the
standard. Finally, an automotive-type system that stores fuel tank
vapors for burning in the engine would be another alternative
technology, though it is unlikely that such a system can be simply
characterized and included as an option for design-based certification.
---------------------------------------------------------------------------

\81\ ''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, engine manufacturers must 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.\82\ 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. These permeation requirements
are based on manufacturers using a more effective emission controls
than that specified for recreational vehicles. This is appropriate
because Large SI manufacturers are able to use automotive-grade
materials across their product line, while recreational vehicle
manufacturers have pointed out various limitations in incorporating
automotive-grade materials. Conversely, Large SI manufacturers are not
subject to permeation requirements related to fuel tanks, since almost
all of these tanks are made of metal.
---------------------------------------------------------------------------

\82\ SAE J2260 ``Nonmetallic Fuel System Tubing with One or More
Layers,'' November 1996 (Docket A-2000-01, document II-A-03).
---------------------------------------------------------------------------

Finally, based on available technologies, manufacturers must take
steps to prevent 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.\83\ We are adopting a standard that prohibits
fuel boiling during continuous operation at 30[deg]
C (86[deg]
F).
Engine manufacturers must 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 temperature at which summer-grade gasoline (9 RVP)
typically starts boiling.
---------------------------------------------------------------------------

\83\ 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 exhaust emission standards. While
we do not 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 will eliminate most hot soak
emissions.
Engine manufacturers using design-based certification 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 includes
emission-related installation instructions that the engine manufacturer
gives to equipment manufacturers. While equipment manufacturers must
follow these installation instruction, the engine manufacturer has the
responsibility to certify a system that meets the evaporative-related
requirements described in this section. This should work in practice,
because engine manufacturers already provide equipment manufacturers a
variety of specifications and other instructions to ensure that engines
operate properly in-use after installation in the equipment. The
alternative approach of requiring equipment manufacturers to certify is
impractical because of the very large number of companies involved.
5. What Durability Provisions Apply?
a. Useful life. We are adopting a useful life period of seven years
or until the engine accumulates at least 5,000 operating hours,
whichever comes first. This figure represents a minimum value and may
increase as a result of data showing that an engine model is designed
to last longer. This figure,

[[Page 68297]]

which California ARB has already 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. We
are allowing manufacturers to request a shorter useful life for an
engine family based on information showing that engines in the family
rarely operate beyond the alternative useful-life period. For example,
if engines powering concrete saws are typically scrapped after 2000
hours of operation, this would form the basis for establishing a
shorter useful-life period for those engines.
Manufacturers relying on design-based certification to meet the
evaporative requirements must use good engineering judgment to show
that emission controls will work for at least seven years. This may,
for example, be based on warranty or product-performance history from
component suppliers. This also applies for systems designed to address
crankcase emissions.
b. Warranty. Manufacturers must provide an emission-related
warranty for at least the first half of an engine's useful life (in
operating hours) or three 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. The emission-related
warranty includes components related to controlling evaporative and
crankcase emissions. In addition, we are adopting the warranty
provisions adopted by California ARB for high-cost parts. For emission-
related components whose replacement cost is more than about $400, we
specify 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.
c. Maintenance instructions. We are specifying 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. Manufacturers may schedule
maintenance on catalysts, fuel injectors, electronic control units and
turbochargers after 5,000 hours. For oxygen sensors and cleaning of
fuel-system components, the minimum maintenance interval is 2,500
hours. This fuel-system cleaning must be limited to steps that can be
taken without disassembling components. We have relaxed this from the
proposed interval of 4,500 hours to take into account comments
emphasizing that these maintenance steps will be necessary more
frequently than the proposed interval; this shorter interval also
reflects the comparable provisions that apply to automotive systems.
We are also proposing a diagnostic requirement to ensure that
prematurely failing oxygen sensors or other components are detected and
replaced on an as-needed basis. If operators fail to address faulty
components after a fault signal, we would not consider that engine to
be properly maintained. This could the engine ineligible for
manufacturer in-use testing.
d. Deterioration factors. We are adopting an approach that gives
manufacturers wide discretion in how to establish deterioration factors
for Large SI engines. The general expectation is that manufacturers
will rely on emission measurements from engines that 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.
In deciding to certify an engine family, we can review deterioration
factors to ensure that the projected deterioration accurately predicts
in-use deterioration. We will use results under the in-use testing
program to verify the appropriateness of deterioration factors.
In the first two or three years of certification, manufacturers
will not yet have data from the in-use testing program. Moreover,
manufacturers may choose to rely on technologies and calibrations for
meeting the long-term standards well before 2007 to simplify their
product-development efforts. We are therefore allowing manufacturers to
rely on an assigned deterioration factor to meet the 2004 standards,
while continuing to require manufacturers to meet the applicable
emission standards throughout the useful life for these engines. The
assigned deterioration factor may be derived from any available data
that would help predict the way these systems would perform in the
field, using good engineering judgment.
Manufacturers may develop deterioration factors for crankcase and
evaporative controls. However, we do not expect these control
technologies to experience degradation that would cause a deterioration
factor to be appropriate.
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 LPG fuel quality. Testing data indicate that varying fuel
quality has a 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. As described
in the Final Regulatory Support Document, test data show that emission-
control systems can tolerate substantial fuel-related deposits before
there is any measurable effect on emissions. Moreover, the engine
diagnostic systems described in the next section will notify the
operator when fuel-related deposits prevent an engine from operating at
stoichiometry. In any case, a routine cleaning step should remove
deposits and restore the engine to proper functioning.
Data from in-use testing will provide additional information
related to the effects of varying fuel quality on emission levels. This
information will be helpful in making sure that the deterioration
factors for certifying engines accurately reflect the whole range of
in-use operating variables, including varying fuel quality. Our testing
shows that fuel properties of conventional commercial LPG fuel allow
for durable, long-term control of emissions. However, to the extent
that engines operating in specific areas have inferior fuel quality
that prevents them from meeting emission standards, we will be pursuing
nationwide requirements to set minimum quality standards for in-use LPG
fuel.

[[Page 68298]]

D. Testing Requirements and Supplemental Emission Standards

1. What Duty Cycles Are Used To Measure Emissions?
For 2004 through 2006 model years, we specify the same steady-state
duty cycles adopted by California ARB. For variable-speed engines, this
involves the testing based on the ISO C2 duty 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. A separate duty cycle for the large number of Large SI
engine providing power for constant-speed applications, such as
generators, welders, compressors, pumps, sweepers, and aerial lifts.
Constant-speed testing is 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 must generally test engines on both the C2 and D2
duty cycles. 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. Manufacturers may,
however, choose to certify their engines on only one of these two
steady-state duty cycles. In this case, they would need to take steps
to make sure C2-certified engines are installed only in variable-speed
applications and D2-certified engines are installed only in constant-
speed applications. Engine manufacturers would do this by labeling
their engines appropriately and providing installation instructions to
make sure equipment manufacturers and others are aware of the
restricted certification. Equipment manufacturers are required under
the regulations to follow the engine manufacturer's emission-related
installation instructions.
Starting in 2007, we specify an expanded set of duty cycles, again
with separate treatment for variable-speed and constant-speed
applications. The test procedure is 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 same emission standards that apply to all
duty cycles. In general, the duty cycles are intended to represent
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.
Ambient temperatures in the laboratory must be between 20[deg]
and
30[deg]
C (68[deg]
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 V.D.5.
The warm-up segment begins with a cold-start. This means that the
engine should be near room temperature before the test cycle begins.
(Starting with an engine that is still warm from previous testing is
allowed if good engineering judgment indicates that this will not
affect emissions.) Once the engine is started, it operates 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. For severe-duty engines, the warm-up period is extended up to 15
minutes to account for the additional time needed to stabilize
operating temperatures from air-cooled engines. The 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. In addition, we require manufacturers to
activate emission-control systems as soon as possible after engine
starting to make clear that it is not acceptable to design the
emission-control system to start working only after the defined warm-up
period is complete. In addition, we may measure emissions during the
warm-up period to evaluate whether manufacturers are employing defeat
devices. In contrast, transient testing of heavy-duty highway engines
requires separate cold-start and hot-start measurements, with an 86-
percent weighting assigned to the hot-start portion in calculating an
engine's composite emission level. We believe this approach for nonroad
engines serves to limit cold-start emissions without forcing
manufacturers to focus design and testing resources on this portion of
operation.
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 as fork-lifts and constant-speed engines represent
about 90 percent of the Large SI market. 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. 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.
A separate transient duty cycle applies to engines that are
certified for constant-speed applications only. These engines maintain
a constant speed, but can experience widely varying loads. The
transient duty cycle for these engines includes 20 minutes of engine
operation based on the way engines work in a welder. Note that
manufacturers selling engines for both constant-speed and variable-
speed applications may omit the constant-speed transient test, since
that type of operation is included in the general transient test.
A subset of constant-speed engines are designed to operate only at
high

[[Page 68299]]

load. To address the operating limitations of these engines, we are
adopting a modified steady-state duty cycle if the manufacturer
provides clear evidence showing that engines rarely operate below 75
percent of full load at rated speed. Since most Large SI engines are
clearly capable of operating for extended periods at light loads, we
expect these provisions to apply to very few engines. This modified
duty cycle consists of two equally weighted points, 75 percent and 100
percent of full load, at rated speed. Since the transient cycle
described above involves extensive light-load operation, engines
qualifying for this high-load duty cycle would not need to measure
emissions over the transient cycle. Note that the field-testing
emission standards still apply to engines that don't certify to
transient duty-cycle standards.
Some diesel-derived engines operating on natural gas with power
ratings up to 1,500 or 2,000 kW may be covered by these emission
standards. Engine dynamometers with transient-control capabilities are
generally limited to testing engines up to 500 or 600 kW. At this time
emission standards and testing requirements related to transient duty
cycles will not apply for engines rated above 560 kW. We will likely
review this provision for Large SI engines once we have reached a
conclusion on the same issue for nonroad diesel engines. For example,
if we propose provisions for nonroad diesel engines that address
testing issues for these very large engines, we would likely propose
those same provisions for Large SI engines.
Test procedures related to evaporative emissions are described in
Section V.C.4 above. In general, this involves measuring evaporative
losses during a three-day period of cycling ambient temperatures
between 72[deg]
and 96[deg]
F.
2. What Fuels Are Used During Emission Testing?
For gasoline-fueled Large SI engines, we are adopting the same
specifications we have established 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). These fuel
specifications apply for both exhaust and evaporative emissions.
For LPG, we are adopting the same specifications established by
California ARB. We understand that in-use fuel quality for LPG 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
Final 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. At certification manufacturers provide deterioration factors
that take into account any effects related to the varying quality of
commercially available fuels.
For natural gas, we are adopting specifications similar to those
adopted by California ARB. As described in the Summary and Analysis of
Comments, we have adjusted some of the detailed specifications from the
proposal to reflect new data submitted after the proposal regarding
ranges of fuel properties reflecting current commercial fuels.
Unlike California ARB, we apply the fuel specifications to testing
only for emission measurements, not to service accumulation. Service
accumulation between emission tests may involve certification fuel or
any commercially available fuel of the appropriate type. We similarly
allow manufacturers to choose between certification fuel and any
commercial fuel for in-use measurements to show compliance with field-
testing emission standards.
Since publishing the proposal, we learned about issues related to
Large SI engines that operate around landfills or oil wells, where
engines may burn naturally occurring gases that are otherwise emitted
to the atmosphere. These gases generally consist of methane, but a wide
range of other constituents may also be mixed in. As a result, engines
may require adjustment over a wide range of settings for spark timing
and air-fuel ratio to maintain consistent combustion. We generally
believe that engine manufacturers should design their engines to
operate with automatic feedback controls as much as possible to avoid
the need for operators to manually adjust engines. However, in cases
involving these noncommercial fuels, there is no way to improve the
quality of the fuel to conform to any standardized specifications.
Also, it is clearly preferred to capture and burn these gases than to
emit them directly to the atmosphere, both to prevent greenhouse-gas
emissions and to avoid wasting this source of fuel. To address this
concern, we are adopting special provisions for engines burning
noncommercial fuels if they are unable to meet emission standards over
the full range of adjustability needed to accommodate the varying fuel
properties. Manufacturers would show that these engines can meet
emission standards using normal certification fuels, but the normal
provisions related to adjustable parameters would not apply. To
properly constrain this provision, we are including four requirements.
First, manufacturers would need to add information on an engine label
instructing operators how to make adjustments that would allow for
maintained emission control and overall engine performance. Second,
manufacturers would include additional label language to warn operators
that the engine may be used only in applications involving
noncommercial fuels. Third, manufacturers must separate these engines
into a distinct engine family. Fourth, manufacturers must keep a record
of individual sales of such engines.
3. Are There Production-Line Testing Provisions for Large SI Engines?
The provisions described in Section II.C.4 apply to Large SI
engines. These 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 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 do not require routine transient testing of
production-line engines. Transient testing of production-line engines
would add a substantial burden, since many manufacturers have limited
emission-sampling capability at production facilities; also, these
production facilities might be located at multiple sites. We believe
that steady-state emission measurements will give a good indication of
the manufacturers' ability to build engines consistent with the
prototypes on which their certification data are based. We reserve the
right, however, 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 recommend doing
transient tests to better ensure that in-use tests will not reveal
problems in controlling emissions during transient

[[Page 68300]]

operation. Manufacturers need not make any measurements to show that
production-line engines meet field-testing emission standards.
We expect manufacturers generally to certify their engines to the
evaporative requirements using a design-based approach. Accordingly,
the technologies we expect manufacturers to use for controlling
evaporative emissions are not subject to variation as a result of
production procedures, so we are not requiring production-line testing
related to the evaporative requirements.
4. Are There 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 requiring engine manufacturers to
conduct emission tests on a small number of field-aged engines to show
they meet emission standards.
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. Most
companies will 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.
Manufacturers in unusual circumstances may 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.
While the regulations allow us to select an engine family every
year from an engine manufacturer, there are several reasons why small-
volume manufacturers may 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 may provide adequate data to show
compliance for that engine family for a number of years, provided that
the manufacturer continues to produce those engines without
significantly redesigning them in a way that might affect their in-use
emissions performance and that we do not have other reason to suspect
noncompliance. Also, where we have evidence that a manufacturer's
engines are likely in good in-use compliance, we 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 may expect us to select their
engine families less frequently, especially if other available data
pointed toward in-use compliance. 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 is 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.
As an alternative, manufacturers may use the specified equipment
and procedures for testing engines without removing them from the
equipment (referred to in this document as field testing). See Section
V.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 is demonstrated by comparing the measured emission levels to
the field-testing emission standards, which 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 are not eligible to participate in the in-use averaging,
banking, and trading program (described below).
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). Along with the in-use testing program, we would allow
manufacturers to demonstrate that they have designed their engines to
control emissions substantially below the emission standards that
apply. If manufacturers are able to show that they have already been
reducing emissions more than required by the standards, including
appropriate consideration for deterioration and compliance margins,
this may allow us to conclude that these accumulated additional
emission reductions are sufficient to offset the high emissions from a
failing engine family. In concept, this approach serves much like a
banking program to recognize manufacturers' efforts to go beyond the
minimum required emission reductions.
This approach differs from the specific in-use emission-credit
program that we proposed. This more general approach is preferred for
two primary reasons. First, while we proposed to limit the in-use
emission-credit program to transient testing in the laboratory,
manufacturers will now be able to use emission data generated from
field testing to characterize an engine family's average emission
level. This becomes necessarily more subjective, but allows us to
consider a wider range of information in evaluating the degree to which
manufacturers are complying with emission standards across their
product line. Second, this approach makes clearer the role of the
emission credits in our consideration to recall failing engines. As we
described in the proposal, we plan to consider average emission levels
from multiple engine families in deciding whether to recall engines
from a failing engine family. We therefore believe it is not
appropriate to have a detailed emission-credit program defining
precisely how and when to calculate, generate, and use credits that do
not necessarily have value elsewhere.
The regulations do not specify how manufacturers would generate
emission credits to offset a nonconforming engine family. This gives us
the ability to consider any appropriate test data in deciding what
action to take. In generating this kind of information, some general
guidelines would apply. For example, we would expect manufacturers to
share test data from all engines and all engine families tested under
the in-use testing program, including nonstandard tests that might be
used to screen engines for later measurement. This allows us to
understand the manufacturers' overall level of performance in
controlling emissions to meet emission standards. Average emission
levels should be calculated over a running three-year period to include
a broad range of

[[Page 68301]]

testing without skewing the results based on old designs. Emission
values from engines certified to different tiers of emission standards
or tested using different measurement procedures should not be combined
to calculate a single average emission level. Average emission levels
should be calculated according to the following equation, rounding the
results to 0.1 g/kW-hr:
[GRAPHIC]
[TIFF OMITTED]
TR08NO02.000

Where:
Average EL=Average emission level in g/kW-hr.
Sales_i=The number of eligible sales, tracked to the point of
first retail sale in the U.S., for the given engine family during the
model year.
_i(STD-CL)=The difference between the emission standard and
the average emission level for an in-use testing family in g/kW-hr.
UL_i=Useful life in hours.
Power_i=The sales-weighted average rated brake power for an
engine family in kW.
LF_i=Load factor or fraction of rated engine power utilized
in use; use 0.50 for engine families used only in constant-speed
applications and 0.32 for all other engine families.

The anticipated crankcase and evaporative emission-control
technologies generally are best evaluated simply by checking whether or
not they continue to function as designed, rather than implementing a
program to measure these emissions from in-use engines. As a result, we
may inspect in-use engines to verify that these systems continue to
function properly throughout the useful life, but are not requiring
manufacturers to include crankcase or evaporative measurements as part
of the in-use testing program described in this section.
5. What Are the Field-Testing Emission Standards and Test Procedures?
To address concerns for controlling emissions outside of the
certification duty cycles and to enable field-testing of Large SI
engines, we are adopting 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, testing of
in-use engines has shown that emissions can vary dramatically under
certain modes of operation.
Second, this provides a low-cost method of testing in-use engines,
which facilitates in-use compliance programs.
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 a framework for
requiring that engines 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
adopting supplemental emission standards that apply more broadly than
the duty-cycle standard, as detailed below. These standards apply to
all regulated pollutants (NO_X, HC, and CO) under all normal
operation (steady-state or transient). We exclude abnormal operation
(such as very low average power and extended idling time), but do not
restrict operation to any specific combination of speeds and loads. In
addition, the field-testing standards 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. How do the field-testing standards apply? 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 adopting specific field-
testing standards for 2004 through 2006 model year engines, we will
allow this as an option. In this case, manufacturers would conduct the
field testing as described here to show that their engines meet the 5.4
g/kW-hr HC+NO_X standard and the 50 g/kW-hr CO standard. This
may 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 expect any
additional variability in field-testing measurements not to affect
manufacturers' ability to meet the same emission standards.
The 2007 field-testing standards are based on emission data
measured on engines with the same emission-control technology used to
establish the duty-cycle standards. As described above for the duty-
cycle standards, we are adopting a flexible approach to address the
tradeoff between HC+NO_X and CO emissions. Table V.D-1 shows
the range of values that define the standard for showing compliance for
field-testing measurements. The higher numerical values of the Tier 2
standards for field testing (compared with duty-cycle testing) reflect
the observed variation in emissions for varying engine operation, and
the projected effects of ambient conditions on the projected
technology. 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).

Table V.D-1.--Samples of Possible Alternative Field-Testing Emission
Standards for Large SI Engines(g/kW-hr) *
------------------------------------------------------------------------
HC+NO_X CO
------------------------------------------------------------------------
3.8......................................................... 6.5
3.1......................................................... 8.5
2.4......................................................... 11.7
1.8......................................................... 16.8
1.4......................................................... 23.1

[[Page 68302]]

1.1......................................................... 31
------------------------------------------------------------------------
* As described in the Final Regulatory Support Document and the
regulations, the values in the table are related by the following
formula: (HC+NO_X) x CO0.791 = 16.78. These values follow directly from
the logarithmic relationship presented with the proposal in the Draft
Regulatory Impact Analysis.

We generally require manufacturers to show at certification that
they are capable of meeting all standards that apply for the useful
life. 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, manufacturers must show in their
application for certification that they are able to meet the field-
testing standards. Manufacturers must 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. Manufacturer will provide a detailed description of
any testing, engineering analysis, and other information that forms the
basis for the statement. This will 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 are
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. Manufacturers
must design their engines to broadcast instantaneous speed and torque
values to the onboard computer and ensure that emission sampling is
possible after engine installation.
The test 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 may use the field-
testing equipment and procedures to get a low-cost, valid emission
measurement at the production line. Manufacturers may also 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 II.C.4
for more information.
c. What limits are placed on field testing? The field-testing
standards apply to all normal operation. This may 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 adopting several
parameters to narrow the range of engine operation that is subject to
the field-testing standards. For example, emission sampling for field
testing does not include engine starting.
Engines can often operate at extreme environmental and geographic
conditions (temperature, altitude, etc.). To narrow the range of
conditions for the design engineer, we are limiting 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.
Some additional limits to define ``normal'' operation apply to
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 field-testing standards is feasible. These
restrictions apply to both variable-speed and constant-speed engine
applications.
First, measurements with more than 2 minutes of continuous idle are
excluded. This means that an emission measurement from a forklift while
it idled for 5 minutes will not be considered valid. On the other hand,
an emission measurement from a forklift that idled for multiple 1-
minute periods 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 therefore do 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 is significantly less
effective. 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, 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. The data presented in Chapter 4
of the Final Regulator Support Document show that engines can meet the
emission standards when operating above 5 percent of rated power.
Third, some 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 adopting provisions allowing
manufacturers to meet separate standards for these engines for steady-
state operation. For engines qualifying for these different steady-
state standards, we specify that a valid sample for field testing must
include less than 10 percent of operation at 90 percent or more of
maximum power. We 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 can 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. Manufacturers may request a different
threshold to allow more open-loop operation. Before we approve such a
request, the engine manufacturer would need to have a plan for ensuring
that the engines in their final installation do not routinely operate
at loads above the specified threshold.
An additional parameter to consider is the minimum sampling time
for field testing. A longer period allows for

[[Page 68303]]

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 applying 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 do not specify a maximum sampling time. We expect manufacturers
testing in-use engines to select an approximate sampling time before
measuring emissions; however, the standards apply for any sampling time
that meets the minimum. When selecting an engine family for the in-use
testing program, we will develop a plan with direction related to the
way manufacturers conduct the emission-sampling effort, such as
sampling time or specific types of engine operation, to ensure that
testing provides relevant data.
d. How do I test engines in the field? To test engines without
removing them from equipment, analyzers are connected to the engine's
exhaust to detect emission concentrations during normal operation.
Exhaust volumetric flow rate and continuous power output are also
needed to convert the analyzer responses to units of g/kW-hr for
comparing to emission standards. These values can be calculated from
measurements of the engine intake flow rate, the exhaust air-fuel ratio
and the engine speed, and from torque information.
Available small analyzers and other equipment may be adapted for
measuring emissions from field equipment. A portable flame ionization
detector can measure total hydrocarbon concentrations. Methane
measurement currently requires more expensive laboratory equipment that
is impractical for field measurements. Field-testing standards are
therefore be based on total hydrocarbon emissions. A portable analyzer
based on zirconia technology measures NO_X emissions. A
nondispersive infrared (NDIR) unit can measure CO. Emission samples can
best be drawn from the exhaust flow directly downstream of the catalyst
material to avoid diluting effects from the end of the tailpipe.
Installing a sufficiently long tailpipe extension is also an acceptable
way to avoid dilution. Mass flow rates also factor into the torque
calculation; this may 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. Manufacturers must
therefore design their engines to continuously monitor engine speed and
torque. The tolerance for speed measurements, which is relatively
straightforward, is +/-5 percent. For torque, the onboard computer
needs to convert measured engine parameters into useful units.
Manufacturers generally will 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, manufacturers must 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 Final Regulatory Support Document.

E. Special Compliance Provisions

We are adopting hardship provisions to address the particular
concerns of small-volume manufacturers, which generally have limited
capital and engineering resources. These hardship provisions are
generally described in Section VII.C. For Large SI engines, we are
adopting a longer available extension of the deadline, up to four
years, for meeting emission standards for companies that qualify for
special treatment under the hardship provisions. We will, however, not
extend the deadline for compliance beyond the four-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.
We are not finalizing the proposed interim emission standards
proposed for small-volume manufacturers. We believe we can accomplish
the same objectives with more flexibility, and potentially with greater
net emission reductions, by relying on the hardship provisions.
In addition, we are waiving the requirement for small-volume
manufacturers to broadcast engine speed and torque values. These
companies may choose to do this to enable field-testing of their
products, but may be constrained in developing this capability to the
extent that they rely on component suppliers to provide systems that
meet EPA requirements.

F. Technological Feasibility of the Standards

We are adopting 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 is not 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.
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 Final 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
emission standards nationwide in 2004 will therefore generally require
manufacturers only to produce greater numbers of the engines complying
with the California standards.
Chapter 4 of the Final Regulatory Support Document further
describes data and rationale showing why we believe that the 2007 model
year emission standards under the steady-state and transient duty-
cycles and field-testing procedures are feasible. In

[[Page 68304]]

summary, testing from Southwest Research Institute 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 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 does not allow manufacturers enough stability between
introduction of different phases of emission standards to prepare for
complying with the full set of requirements in this final rule and to
amortize their fixed costs. 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 new standards including new test cycle requirements. The
provisions to allow ``family banking'' for early compliance provide an
additional tool for companies that choose to spread out their design
and certification efforts.
The new emission standards will either have no impact or a positive
impact with respect to noise, energy, and safety, as described in
Chapter 4 of the Final Regulatory Support Document. In particular, the
anticipated fuel savings associated with the expected emission-control
technologies will 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
near-term and long-term emission standards allows manufacturers enough
time to optimize these designs to most effectively reduce emissions
from the wide range of Large SI equipment applications.

VI. Recreational Marine Diesel Engines

This section describes the new provisions for 40 CFR part 94, which
apply to engine manufacturers and importers. We are applying the same
general compliance provisions from 40 CFR part 94 for engine
manufacturers, equipment manufacturers, operators, rebuilders, and
others. See Section II for a description of our general approach to
regulating nonroad engines and how manufacturers show that they meet
emission standards.

A. Overview

We are adopting exhaust and crankcase emission standards for
recreational marine diesel engines with power ratings greater than or
equal to 37 kW. We are adopting emission standards for HC,
NO_X, CO, and PM beginning in 2006. We believe manufacturers
will be able to use technology developed for land-based nonroad and
commercial marine diesel engines. To encourage the introduction of low-
emission technology, we are also adopting voluntary ``Blue Sky''
standards which are 40 percent lower than the mandatory standards. We
also recognize that there are many small businesses that manufacture
recreational marine diesel engines. We are therefore including several
regulatory options for small businesses that will help minimize any
unique burdens caused by emission regulations.
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 Rule

The standards in this section apply to recreational marine diesel
engines. We excluded these engines from the requirements applying to
commercial marine diesel engines because at the time we thought their
operation in planing mode might impose design requirements on
recreational boat builders and to allow us more time for further
evaluation prior to setting standards (64 FR 73300, December 29, 1999).
Commercial marine vessels tend to be displacement-hull vessels,
designed and built for a unique commercial application (such as towing,
fishing, or general cargo). Power ratings for engines used on these
vessels are analogous to land-based applications, and these engines
generally have warranties for 2,000 to 5,000 hours of use. Recreational
vessels, on the other hand, tend to be planing vessels. 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, so recreational marine engines have shorter warranties than
their commercial counterparts. In our previous rulemaking, recreational
engine industry representatives raised concerns about the ability of
these engines to meet the commercial standards without substantial
changes in the size and weight of the engine. Such changes may 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 with fiberglass molds, this may be a significant burden for
recreational vessel builders.
Our further evaluation of these issues leads us to conclude that
recreational marine diesel engines can achieve those same emission
standards without significant impacts on engine size and weight, and
therefore without significant impacts on vessel design. Section VI.G of
this document, Chapters 3 and 4 of the Final Regulatory Support
Document, and Section II.A of the Summary and Analysis of Comments
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 establishing a separate
regulatory program for recreational marine diesel engines in this rule,
with most aspects the same as for commercial marine diesel engines but
with certain aspects of the program tailored to these applications,
notably the not-to-exceed emissions requirements.
To distinguish between commercial and recreational marine diesel
engines for the purpose of emission controls, it is necessary to define
``recreational marine diesel engine.'' The commercial marine diesel
engine rule defined recreational marine engine as 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

[[Page 68305]]

VIOLATION OF FEDERAL LAW SUBJECT TO PENALTY.''
We are revising this definition to include a requirement that a
recreational marine engine must be a Category 1 marine engine (have a
displacement of less than 5 liters per cylinder). Category 2 marine
engines are generally designed with characteristics similar to
commercial marine engines. Vessels using engines of this size generally
require engines that can operate longer at higher power than typical
recreational boats; therefore, these engines generally have a lower
power density and are not offered in a ``recreational'' rating.
For the purpose of the recreational marine diesel engine definition
included in the proposal, 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.'' Because certain vessels that are used for pleasure
may have operating characteristics that are more similar to commercial
marine vessels (such as 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'' does 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 that carry one or more passengers; or (3)
vessels used solely for competition. For the purposes 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 this rulemaking on these
definitions. Engine manufacturers were concerned that the definitions
may be unworkable for engine manufacturers, because 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 corresponding characteristics for planing,
power density, and performance requirements.
We are not revising our existing definition of recreational marine
vessel. As discussed in the Summary and Analysis of Comments, a vessel
will be considered recreational if the boat builder intends that the
customer will operate it consistent with the recreational-vessel
definition. Relying on the boat builder's intent is necessary because
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. The engine manufacturer will not be
expected to ensure that their engines are used only in recreational
craft; however, they would be required to label their recreational
engines as described above. The vessel builders will then be required
to install properly certified recreational (or commercial) marine
engines in recreational vessels and certified commercial marine engines
in commercial vessels.

C. Emission Standards for Recreational Marine Diesel Engines

This section describes the new emission standards and
implementation dates, with an outline of the technology that can be
used to achieve these levels. The technological feasibility discussion
below (Section VI.G) describes our technical rationale in more detail.
1. What Are the Emission Standards and Compliance Dates?
The emission standards for recreational marine diesel engines are
the same as the Tier 2 standards for commercial marine diesel engines
with two years additional lead time. We are setting the standards at
the same level because recreational marine diesel engines can use all
the technologies projected for Tier 2 and these technologies are
expected to lead to compliance. As with commercial marine engines this
technology will be available in the lead time provided to allow
compliance with the emission standards. 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. However, the technology listed
above can be used to meet the emission standards while still meeting
the performance requirements of a recreational engine.
We are adopting the commercial marine engine standards for
recreational marine diesel engines, allowing two years beyond the dates
that standards apply for the commercial engines. This gives engine
manufacturers additional lead time in adapting technology to their
recreational marine diesel engines. For manufacturers producing only
recreational marine engines the implementation dates provide three to
six years of lead time beyond this notice. Based on our evaluation of
the industry, we believe that manufacturers who produce only
recreational marine engines would likely be small businesses and would
have the option of additional lead time, and other flexibility, as
discussed in Section VI.E. The emission standards and implementation
dates for recreational marine diesel engines are presented in Table
VI.C-1. The subcategories refer to engine displacement in liters per
cylinder.

Table VI.C-1.--Recreational Marine Diesel Emission Standards and Implementation Dates
----------------------------------------------------------------------------------------------------------------
HC+NO_X g/kW- Implementation
Subcategory hr PM g/kW-hr CO g/kW-hr date
----------------------------------------------------------------------------------------------------------------
power £= 37 kW disp < 0.9............. 7.5 0.40 5.0 2007
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 £= 2.5........................... 7.2 0.20 5.0 2009
----------------------------------------------------------------------------------------------------------------

[[Page 68306]]

Manufacturers commented that engines with less than 2.5 liters per
cylinder, but more than 560 kW would have no lead time beyond the land-
based nonroad diesel engine standards and that some commercial marine
engines in this category would actually have to certify two years
before nonroad engines. In this case this is caused by the way we
define subclasses, but has technology and cost implications for the
engines involved. To address this, we are providing an optional
implementation date of 2008 for certain commercial and recreational
marine engines (see the Summary and Analysis of Comments for more
detail). To be eligible for this option, the engine must be derived
from a land-based nonroad engine with a rated power greater than 560 kW
and have a displacement of 2.0 to 2.5 liters per cylinder. To use this
option, we are requiring that engines certified under this option meet
an HC+NO_X standard of 6.4 g/kW-hr through model year 2012.
We believe this emission level, which matches the Tier 2 level for
land-based nonroad engines, should be achievable given the extra lead
time for development. Testing would still be performed on the
appropriate marine duty cycles. Based on our analysis in the Final
Regulatory Impact Analysis for commercial marine engines,
HC+NO_X emissions measured over the marine duty cycles should
be similar to those measured over the land-based nonroad duty cycle.
We are also adopting not-to-exceed emission standards and related
requirements similar to those finalized for commercial marine diesel
engines. This is discussed below in Section VI.C.8.
2. Will I Be Able To Average, Bank, or Trade Emissions Credits?
Manufacturers may use emission credits from recreational marine
diesel engines to show that they meet emission standards. Section
II.C.3 gives an overview of the emission-credit program, which is
consistent with what we have adopted for Category 1 commercial marine
diesel engines. The emission-credit program covers HC+NO_X
and PM emissions, but not CO emissions.
Consistent with our land-based nonroad and commercial marine diesel
engine regulations, manufacturers may not simultaneously generate
HC+NO_X credits while using 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 are adopting 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 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 may cause increased emissions in areas such as ports that may
have a need for PM or NO_X emission reductions. Nonetheless,
it is acknowledged that recreational marine diesel engines constitute a
small fraction of PM and HC + NO_X emissions in nonattainment
areas.
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 more options in
implementing their engine designs. However, if we revisit these
standards later, we will have to reevaluate this issue in the context
of whether future advances in technology would result in a large amount
of accumulated credits that would adversely impact the timely
implementation of any new requirements.
Consistent with the land-based nonroad diesel rule, we will also
not allow manufacturers to use credits generated on land-based engines
for demonstrating compliance with marine diesel engines. In addition,
credits may not be exchanged between recreational and commercial marine
engines. The emission standards for recreational engines are based on
the baseline levels of current recreational marine engines and the
capability of technology to reduce emissions from recreational marine
engines. The standard is, therefore, premised on the capability and use
of recreational marine technology and not on the capability and use of
technology on other engines. Emissions from land-based, commercial, and
recreational marine engines are measured over different duty cycles and
have different useful lives. Correction factors would be difficult to
generate and they would add complexity and uncertainty to the value of
the credits. Furthermore, we are concerned that allowing cross program
trading could create an inequity between manufacturers with diverse
product lines and those with more limited offerings, thereby
potentially creating a competitive advantage for diverse companies over
small companies selling only recreational marine engines. If a
manufacturer were to do this, we do not believe it is likely that they
would sell emission credits at a price that would be economical for
small manufacturers.
We will allow early banking of emission credits relative to the
standard. Early banking of emission credits may allow for a smoother
implementation of the recreational marine standards. These credits are
generated relative to the new emission standards and are undiscounted.
We will also allow manufacturers to generate early credits relative
to their pre-control emission levels. If manufacturers choose this
option they will have to develop baseline emission levels specific to
each participating engine family. 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 certify to
the standards to generate credits, but the credits will be calculated
relative to the generated baseline rather than the standards. 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 as well as other sources of potential uncertainty
about the representativeness if the baseline. Manufacturers commented
that credits should not be generated under the early banking program
for the portion of NO_X reductions above the MARPOL Annex VI
standard. We believe this approach is reasonable since this should be a
common upper limit for all engines. Therefore, if manufacturers use
this option, any baseline NO_X levels determined to be above
the MARPOL Annex VI standard must be adjusted to that level for
determining early credits.
3. Is EPA Proposing Voluntary Standards for These Engines?
a. Blue Sky. We are adopting voluntary emission standards based on
a 45-percent reduction beyond the mandatory standards. An engine family
meeting the voluntary standards

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qualifies for designation as Blue Sky Series engines. These voluntary
standards are the same as those adopted for commercial marine diesel
engines (see Table VI.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 that apply to
this category of engines, including allowable maintenance, warranty,
useful life, rebuild, and deterioration factor provisions. This program
is effective immediately when we publish this rule. To maximize the
potential for other groups to create incentive programs, without
double-counting, we do not allow manufacturers to earn marketable
credits for their Blue Sky Engines.

Table VI.C-2.--Blue Sky Voluntary Emission Standards for Recreational
Marine Diesel Engines
[g/kW-hr]
------------------------------------------------------------------------
Rated brake power (kW) HC+NO_X PM
------------------------------------------------------------------------
power £= 37 kW displ.<0.9............... 4.0 0.24
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 for
NO_X emissions from marine diesel engines rated above 130 kW.
We encourage engine manufacturers to make Annex VI-compliant engines
available and boat builders to purchase and install them before we
apply the EPA Tier 2 standards. If the treaty enters into force, the
standards 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.
4. What Durability Provisions Apply?
Several provisions help ensure that engines control emissions
throughout a lifetime of operation. Section II.C gives a general
overview of durability provisions associated with emissions
certification. This section discusses these provisions specifically for
recreational marine diesel engines.
a. How long do my engines have to comply? Manufacturers must
produce engines that comply over a useful life of ten years or until
the engine accumulates 1,000 operating hours, whichever occurs first.
The hours requirement is a minimum value for useful life, and
manufacturers must 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
1,000 hour value, we will consider evidence such as whether the engines
continue to reliably deliver the necessary power output without an
increase in fuel consumption that the user would find unacceptable and
thus might trigger a maintenance or rebuild action by the user.
b. How do I demonstrate emission durability? We are extending the
durability demonstration requirements for commercial marine diesel
engines to also cover recreational marine diesel engines. This means
that recreational marine engine manufacturers, using good engineering
judgment, will generally need to test one or more engines for emissions
before and after accumulating the number of hours consistent with the
engine useful life (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 may 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 also specify that manufacturers must collect durability data and
generate deterioration factors using the same methods established for
commercial marine diesel engines. 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