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

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Other Related Documents

[Federal Register: December 7, 2000 (Volume 65, Number 236)]
[Proposed Rules]
[Page 76797-76829]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07de00-20]

[[Page 76797]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 86, 94, 1048 and 1051

[FRL-6907-6]

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

AGENCY: Environmental Protection Agency.

ACTION: Advance notice of proposed rulemaking.

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SUMMARY: With this advance notice of proposed rulemaking (ANPRM), we
are continuing with our process of establishing standards for nonroad
engines and vehicles that cause or contribute to air pollution. The
ANPRM addresses nonroad engines and vehicles that have yet to be
regulated by EPA, including: Large spark ignition (SI) engines such as
those used in forklifts and airport tugs; Recreational vehicles using
spark ignition engines such as off-highway motorcycles, all-terrain
vehicles, and snowmobiles; and Recreational marine diesel engines and
marine spark ignition sterndrive and inboard engines.
These engines and vehicles contribute to ozone, carbon monoxide
(CO), and particulate matter (PM) nonattainment. We are also concerned
in some cases about personal exposure to high levels on CO, air toxics,
and PM to persons operating or close to this equipment. With this
ANPRM, we invite early input to the process to establishing standards
and programs for these nonroad sources.
We are also seeking comment on whether EPA should pursue rulemaking
to establish more stringent emissions standards for highway
motorcycles. While standards are in place for highway motorcycles, the
current standards were established more than twenty years ago. Since
off-highway motorcycles are included this ANPRM as part of nonroad
recreational vehicles, we believe it may be appropriate to consider
standards for both types of motorcycles together.

DATES: We request comment on this Advance Notice by February 5, 2001.

ADDRESSES: You may send written comments in paper form and/or by e-
mail. Send paper copies of written comments (in duplicate if possible)
to the contact person listed below. You may also submit comments via e-
mail to ``nranprm@epa.gov''. In your correspondence, refer to Docket A-
2000-01.
EPA's Air Docket makes materials related to this rulemaking
available for review in Dockets A-2000-01 and A-98-01. These materials
are located at U.S. Environmental Protection Agency (EPA), Air Docket
(6102), Room M-1500, 401 M Street, SW, Washington, DC 20460 (on the
ground floor in Waterside Mall) from 8:00 a.m. to 5:30 p.m., Monday
through Friday, except on government holidays. You can reach the Air
Docket by telephone at (202) 260-7548 and by facsimile at (202) 260-
4400. We may charge a reasonable fee for copying docket materials, as
provided in 40 CFR part 2.

FOR FURTHER INFORMATION CONTACT: Margaret Borushko, U.S. EPA, National
Vehicle and Fuels Emission Laboratory, 2000 Traverwood, Ann Arbor, MI
48105; Telephone: (734) 214-4334, Fax: (734) 214-4050, e-mail:
borushko.margaret@epa.gov.

SUPPLEMENTARY INFORMATION: Electronic Copies of Documents
This document is also available electronically from the EPA
Internet Web site. This service is free of charge, except for any cost
already incurred for internet connectivity. The electronic version of
this document is made available on the day of publication on the
primary web site listed below. We also publish Federal Register
documents 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 document and the software into which the document may be
downloaded, changes in format, page length, etc., may occur.

Table of Contents

I. Overview
II. Air Quality
III. Recreational Vehicles
IV. Highway Motorcycles
V. Recreational Marine Engines
VI. Large Spark Ignition Engines
VII. Public Participation
VIII. Regulatory Flexibility
IX. Administrative Designation and Regulatory Analysis
X. Statutory Provisions and Legal Authority

I. Overview

A. History of Nonroad Engine Regulations

The process of establishing standards for nonroad engines began in
1991 with a study to determine whether emissions of carbon mononxide
(CO), oxides of nitrogen ( NOX), and volatile organic
compounds (VOCs) from new and existing nonroad engines, equipment, and
vehicles are significant contributors to ozone and CO concentrations in
more than one area that has failed to attain the national ambient air
quality standards for ozone and CO.\1\ In 1994, EPA finalized its
finding that nonroad engines as a whole ``are significant contributors
to ozone or carbon monoxide concentrations'' in more than one ozone or
carbon monoxide nonattainment area.\2\
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\1\ ``Nonroad Engine and Vehicle Emission Study--Report and
Appendices,'' EPA-21A-201, November 1991 (available in Air docket A-
91-24). It is also available through the National Technical
Information Service, referenced as document PB 92-126960.
\2\ 59 FR 31306 (July 17, 1994).
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Upon this finding, EPA was tasked by the Clean Air Act (CAA or the
Act) to establish standards for all classes or categories of new
nonroad engines that cause or contribute to air quality nonattainment
in more than one ozone or carbon monoxide (CO) nonattainment area.
Since the finding in 1994, EPA has been engaged in the process of
establishing programs to control emissions from nonroad engines used in
many different applications. Nonroad categories already regulated
include:
Land-based compression ignition (CI) engines (e.g., farm
and construction equipment),
Small land-based spark-ignition (SI) engines (e.g., lawn
and garden equipment, string trimmers),
Marine engines (outboards, personal watercraft, CI
commercial)
Locomotive engines

B. Today's ANPRM

Today's ANPRM provides an initial overview of possible regulatory
strategies for nonroad vehicles and engines that have yet to be
regulated under EPA's nonroad engine programs. It is a continuation of
the process of establishing standards for nonroad engines and vehicles,
as required by CAA section 213(a)(3). If, as expected, standards for
these engines and vehicles are established, essentially all new nonroad
engines will be required to meet emissions control requirements. The
rulemaking that begins with this ANPRM therefore is the final round of
initial regulations for nonroad engines. The ANPRM covers diesel
engines used in recreational marine applications. The ANPRM also covers
several nonroad spark ignition (SI) engine applications, as follows:
Land-based recreational engines (for example, engines used
in snowmobiles,

[[Page 76798]]

off-highway motorcycles, and all-terrain vehicles (ATVs))
Marine sterndrive and inboard (SD/I) engines \3\
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\3\ As a shorthand notation in this document, we are using
``recreational marine engines'' to mean recreational marine diesel
engines and all gasoline SD/I engines, even though some SD/I
applications could be commercial.
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Land-based engines rated over 19 kw (Large SI) (for
example, engines used in forklifts); this category includes auxiliary
marine engines, which are not used for propulsion.
We have found that the nonroad engines included in this ANPRM cause
or contribute to air quality nonattainment in more than one ozone or
carbon monoxide (CO) nonattainment area.\4\ CAA section 213(a)(3)
requires EPA to establish standards that achieve the greatest degree of
emissions reductions achievable taking cost and other factors into
account. We plan to propose emissions standards and related programs
consistent with the requirements of the Act and, with this ANPRM, are
seeking early input from interested parties.
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\4\ See Final Finding, ``Control of Emissions from New Nonroad
Spark-Ignition Engines Rated above 19 Kilowatts and New Land-Based
Recreational Spark-Ignition Engines'' elsewhere in today's Federal
Register for EPA's finding for Large SI engines and recreational
vehicles. EPA's findings for marine engines are contained in 61 FR
52088 (October 4, 1996) for gasoline engines and 64 FR 73299
(December 29, 1999) for diesel engines.
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In addition to the nonroad vehicles and engines noted above,
today's ANPRM also reviews EPA requirements for highway motorcycles.
The emissions standards for highway motorcycles were established
twenty-three years ago. California recently adopted new emissions
standards for highway motorcycles and new standards have also been
proposed internationally. There may be opportunities to reduce
emissions in a way that also allows manufacturers to benefit from
harmonized requirements, which may reduce product lines and production
costs. In addition, we believe it is important to consider the
emissions standards for highway motorcycles in the context of setting
standards for off-highway motorcycles. We are interested in providing
regulatory programs for off-highway and highway motorcycles that are
consistent, and which may also allow for the transfer of technology
across product lines for manufacturers.
This ANPRM covers engines and vehicles that vary in design and use,
and many readers may only be interested in one or two of the
applications. There are various ways we could group the engines and
present information. For purposes of this ANPRM, we have chosen to
group engines by common applications (e.g, recreational land-based
engines, marine engines, large spark ignition engines used in
commercial applications). We have attempted to organize the document in
a way that allows each reader to focus on the applications of
particular interest. The Air Quality discussion which follows in
section II is general in nature and applies to all the categories
covered by the ANPRM. Sections III through VI of the ANPRM present
self-contained discussions of standards and programs for each of the
vehicle and engine categories. While some of the information may be
repetitive among the discussions, we hope that this structure helps the
reader focus on the categories and information of interest. The
remaining sections VII through X are generally applicable to all of the
engines and vehicles.

II. Air Quality

A. Overview

As directed by the Act, EPA has set National Ambient Air Quality
Standards for, among other pollutants, ground-level carbon monoxide,
ozone, NO2, and particulate matter.\5\ States are divided
into discrete areas for air quality planning purposes. Currently, 17
areas around the U.S. are classified as CO nonattainment areas.
Additionally, 31 areas are not in attainment with ozone air quality
standards.
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\5\ See 42 U.S.C. 7409.
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State and local governmental organizations charged with designing
and implementing emission control programs to bring specific areas into
attainment with these air quality standards have mounted significant
efforts in recent years to reduce CO and ozone concentrations. Their
state implementation plans, combined with federal stationary and mobile
source emission control programs, have yielded encouraging signs of
success. Emissions of the targeted pollutants have been significantly
reduced in many areas. Average carbon monoxide and ozone levels, as
well as the number of nonattainment areas, are beginning to decrease.
We project, however, that emission increases accompanying general
growth and economic expansion will eventually outpace per-source
emission rate reductions. Increases in the number of sources, as well
as increased use of existing sources, mean that even full
implementation of current emission control programs may fall short of
that needed to achieve long term attainment and maintenance of the air
quality standards.
In addition to nonattainment concerns, we are also concerned about
hazardous air pollutants (air toxics). In August 2000, we proposed a
list of Mobile Source Air Toxics (MSATs) of concern, including those
emitted from nonroad engines.\6\ These pollutants are known or
suspected to have serious health impacts. The engines and vehicles
included in this ANPRM are sources of MSATs which are included on the
proposed list, including diesel exhaust and several components of VOC
emissions.
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\6\ 65 FR 48058, August 4, 2000.
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B. Public Health and Welfare Concerns

The nonroad engines included in this ANPRM and highway motorcycles
all contribute to air pollution with a wide range of adverse health and
welfare impacts. The following sections contain a brief description of
some of the health effects associated with ozone, PM, air toxics and CO
and the importance of continuing to reduce the associated emissions.
This section also contains a brief description of issues that are
unique to the engines and vehicles being considered in this document.
The NPRM will contain a more detailed discussion of the health and
welfare benefits which can be expected from a program regulating these
engines.
1. Ozone and its Precursors
Ground-level ozone, the main ingredient in smog, is formed by
complex chemical reactions of volatile organic compounds (VOC) and
nitrogen oxides ( NOX) in the presence of heat and sunlight.
Ozone forms readily in the lower atmosphere, usually during hot, summer
weather. VOCs are a broad group of compounds composed mainly of
hydrocarbons (HC). Aldehydes, alcohols, and ethers are also present,
but in small amounts. VOCs are emitted from a variety of sources,
including motor vehicles, chemical plants, refineries, factories,
consumer and commercial products, and other industrial sources.
NOX is emitted largely from motor vehicles, nonroad
equipment, power plants, and other sources of combustion.
Ozone is a highly reactive chemical compound which can damage both
biological tissues and man-made materials. When inhaled, ozone can
cause acute respiratory problems; aggravate asthma; cause significant
temporary decreases in lung function of 15 to over 20 percent in some
healthy adults; cause inflammation of lung tissue; may increase
hospital admissions and emergency room visits; and impair the body's
immune system defenses,

[[Page 76799]]

making people more susceptible to respiratory illnesses. In addition to
human health effects, ozone adversely affects crop yield, vegetation
and forest growth, and the durability of materials. Because ground-
level ozone interferes with the ability of a plant to produce and store
food, plants become more susceptible to disease, insect attack, harsh
weather and other environmental stresses. Ozone causes noticeable
foliar damage in many crops, trees, and ornamental plants (i.e., grass,
flowers, shrubs, and trees) and causes reduced growth in plants.
Studies indicate that current ambient levels of ozone are responsible
for damage to forests and ecosystems (including habitat for native
animal species).
Besides their role as an ozone precursor, NOX emissions
produce a wide variety of health and welfare effects.7,8
Nitrogen dioxide can irritate the lungs and lower resistance to
respiratory infection (such as influenza). NOX emissions are
an important precursor to acid rain and may affect both land and water
ecosystems. Atmospheric deposition of nitrogen leads to excess nutrient
enrichment problems (``eutrophication'') in the Chesapeake Bay and
several nationally important estuaries along the East and Gulf Coasts.
Eutrophication can produce multiple adverse effects on water quality
and the aquatic environment, including increased algal blooms,
excessive phytoplankton growth, and low or no dissolved oxygen in
bottom waters. Eutrophication also reduces sunlight, causing losses in
submerged aquatic vegetation critical for healthy estuarine ecosystems.
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\7\ ``U.S. EPA (1995), Review of National Ambient Air Quality
standards for Nitrogen Dioxide, Assessment of Scientific and
Technical Information,'' OAQPS Staff Paper, EPA-452/R-95-005.
\8\ ``U.S. EPA (1993), Air Quality Criteria for Oxides of
Nitrogen,'' EPA/600/8-91/049aF.
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Need for NOX and VOC Control. Photochemical modeling
highlights the fact that ozone pollution is a regional problem, not
simply a local or state problem. Ozone and its precursors are
transported long distances by winds and other meteorological events.
Thus, achieving ozone attainment for an area, and thereby protecting
its citizens from ozone-related health effects, often depends on the
ozone and precursor emission levels of upwind areas. For many areas
with persistent ozone problems, attainment of the ozone NAAQS will
require control strategies for both NOX and VOC that extend
beyond the areas' boundaries.
We expect that reducing NOX and HC emissions from
engines that would be regulated under this potential program would help
reduce the health and welfare effects of ozone.\9\ Manufacturers and
users of snowmobiles provided comments during the ``finding''
rulemaking indicating that snowmobiles should not be regulated for
ozone precursors because snowmobiles are used during cold weather, when
ozone is less of a health concern.\10\ However, ozone precursors are
also responsible for other pollution problems including air toxics,
discussed below, and indirect PM. We are examining the need to reduce
precursors of ozone in the context of this rulemaking and request
comment. In particular, we request comment on whether EPA should
distinguish snowmobiles from other recreational vehicles in regulating
ozone precursors and whether emissions of ozone precursors such as
NOX and VOC should in any case be regulated due to other
pollution problems.
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\9\ The emissions inventory contributions for these sources are
provided in the Final Finding document referenced in footnote 4.
\10\ International Snowmobile Manufacturers Association, Docket
A-98-01, document IV-D-03.
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2. Particulate Matter
Particulate matter (PM) is the general term used for a mixture of
solid particles and liquid droplets found in the air. These particles,
which come in a wide range of sizes, originate from many different
stationary and mobile sources as well as from natural sources. They may
be emitted directly by a source (direct emissions) or formed in the
atmosphere by the transformation of gaseous precursor emissions such as
sulphur dioxide (SO2), nitrogen oxides (NOX), or
organic compounds (secondary particles). Their chemical and physical
compositions vary depending on source location, time of year and
meteorology.
Scientific studies show a link between inhalable PM (alone, or
combined with other pollutants in the air) and a series of significant
health effects. Inhalable PM includes both fine and coarse particles.
Fine particles can be generally defined as those particles with an
aerodynamic diameter of 2.5 microns or less (also known as
PM2.5), and coarse particles are those with an aerodynamic
diameter between 2.5 and 10 microns. All particles 10 microns or
smaller are called PM10. The health and environmental
effects of PM are strongly related to the size of the particles.
Diesel particles are a component of both coarse and fine PM, but
fall mostly in the fine range. Both coarse and fine particles can
accumulate in the respiratory system and are associated with numerous
health effects. Exposure to coarse fraction particles is primarily
associated with the aggravation of respiratory conditions such as
asthma. Fine particles are more deeply inhaled into the lungs than
course particles. They are most closely associated with such health
effects as decreased lung function, increased hospital admissions and
emergency room visits, increased respiratory symptoms and disease, and
premature death. Sensitive groups that appear to be at greatest risk to
such effects include the elderly, individuals with cardiopulmonary
disease such as asthma, and children.
In addition, PM causes adverse impacts to the environment. Fine PM
is the major cause of reduced visibility in parts of the United States,
including many of our National Parks. Other environmental impacts occur
when particles deposit onto soils, plants, water or materials. For
example, particles containing nitrogen and sulphur that deposit on to
land or water bodies may change the nutrient balance and acidity of
those environments. An ecosystem condition known as ``nitrogen
saturation,'' where addition of nitrogen to soil over time exceeds the
capacity of the plants and microorganisms to utilize and retain the
nitrogen, has already occurred in some areas of the United States. When
deposited in sufficient quantities such as near unpaved roads, tilled
fields, or quarries, particles block sunlight from reaching the leaves,
stressing or killing plants. Finally, PM causes soiling and erosion
damage to materials, including culturally important objects such as
carved monuments and statues.
Recreational marine diesel engines tend to be concentrated in
specific areas of the country (ports, coastal areas, lakes and rivers),
so the emissions contribution of these engines in local areas can be
more important. Consequently addressing PM and other emissions from
recreational marine diesel engines can be an important tool toward the
goal of reducing health and environmental hazards.
Considerations For PM From Recreational Two-Stroke Gasoline
Engines. Two-stroke engines used in land-based recreational vehicles
generally use a fuel and oil mixture to both produce power while
lubricating the engine. As much as 30 percent of the intake charge
passes through the engine unburned and exhausts to the atmosphere. As a
consequence, PM emissions from these engines can be very high. Two
stroke gasoline engines are commonly used in off-highway motorcycles
and snowmobiles.
Snowmobile engine emissions are of particular concern in
environmentally

[[Page 76800]]

sensitive areas, such as Yellowstone National Park. Snowmobiles are
typically powered by 2-stroke engines that have high emissions of
hydrocarbons (HC), carbon monoxide (CO) and PM compared to 4-stroke
engines. Recent studies have concluded that particulate emission rates
from a snowmobile engine are more comparable to those of older, pre-
control diesel engines.11,12 Particle diameters were found
to be typically less than 0.1 microns, which is of respirable size and
able to be delivered into the deepest and most sensitive areas of the
human lung. While formation rates of secondary PM may be lower in the
winter months, PM concentrations can be elevated under some
meteorological conditions (e.g., low mixing heights). We request
comment on the health benefits of reducing PM emissions from
recreational vehicle 2-stroke gasoline engines.
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\11\ ``Characterization of Snowmobile Particulate Emissions
conducted for Yellow Stone Park Foundation Inc.,'' James N. Carroll
and Jeff J. White, Southwest Research Institute, June 1999.
\12\ ``Emissions from Snowmobile Engines using bio-based fuels
and lubricants conducted for the Montana department of Environmental
Quality,'' Jeff J. White and James N. Carroll, Southwest Research
Institute, October 1998.
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3. Air Toxics
These engines are also sources of a number of chemical species
which we have proposed to list as mobile source air toxics (MSATs),
that are known or suspected human or animal carcinogens, or have
serious noncancer health effects.\13\ They include pollutants such as
diesel exhaust, benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and
acrolein, described in more detail below. While the harmful effects of
air toxics are of particular concern in areas closest to where they are
emitted, they can also be transported and affect other geographic
areas. Some can persist for considerable time in the environment.
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\13\ 65 FR 48058, August 4, 2000.
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Many of the air toxics discussed below are components of VOC and we
expect that the HC standards discussed in this document would reduce
exposure to air toxics and therefore reduce the incidence of cancer and
noncancer health effects related to emissions from these engines. We
request comment on the need to control air toxics emissions from the
engines and vehicles included in this document.
Considerations for Diesel Exhaust. Diesel exhaust emissions are a
by-product of incomplete combustion and include gaseous and particulate
components. Gaseous components of diesel exhaust include organic
compounds, sulfur compounds, carbon monoxide, carbon dioxide, water
vapor, and excess air (nitrogen and oxygen). Particulate components
include many organic compounds that are mutagenic as well as several
trace metals (including chromium, manganese, mercury and nickel) that
may have general toxicological significance (depending on the specific
chemical species). In addition, small amounts of dioxins have been
measured in diesel exhaust, some of which may partition to the particle
phase.
Because the chemical composition of diesel exhaust includes
hazardous air pollutants, or air toxics, diesel exhaust emissions are
of concern to the agency. There have been health studies specific to
diesel exhaust emissions which indicate potential hazards to human
health that appear to be specific to this emissions source. For chronic
exposure, these hazards include respiratory system toxicity and
carcinogenicity. Acute exposure also causes transient effects (a wide
range of physiological symptoms stemming from irritation and
inflammation mostly in the respiratory system) in humans though they
are highly variable depending on individual human susceptibility.
The EPA draft Health Assessment Document for Diesel Exhaust was
reviewed in a public session by the Clean Air Scientific Advisory
Committee (CASAC) of EPA's Science Advisory Board on October 12-13,
2000.\14\ The CASAC, in public session, found that the Agency's
conclusion that diesel exhaust is likely to be carcinogenic to humans
by inhalation, was scientifically sound. The comments provided by CASAC
on the draft Assessment are being incorporated into the final
Assessment to be released in late 2000 or early 2001. California EPA
has identified diesel PM as a toxic air contaminant.\15\ Several other
agencies and governing bodies have also designated diesel exhaust or
diesel PM as a ``potential'' or ``probable'' human
carcinogen.16,17,18 The International Agency for Research on
Cancer (IARC) considers diesel exhaust a ``probable'' human carcinogen
and the National Institutes for Occupational Safety and Health have
classified diesel exhaust a ``potential occupational carcinogen''.
Thus, the concern for the health hazard resulting from diesel exhaust
exposures is widespread. We request comment on the health benefits of
reducing PM emissions from marine diesel engines.
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\14\ U.S. EPA(2000) Health Assessment Document for Diesel
Exhaust: SAB Review Draft EPA/600/8-90/057 Office of Research and
Development, Washington, D.C. The document is available
electronically at www.epa.gov/ncea/dieslexh.htm.
\15\ ``Proposed Identification of Diesel Exhaust at a Toxic Air
Contaminant, Health risk assessment for diesel exhaust,'' California
Environmental Protection Agency, April 1998.
\16\ ``Carcinogenic effects of exposure to diesel exhaust,''
NIOSH Current Intelligence Bulletin 50. DHHS, Publication No. 88-
116, 1988.
\17\ ``Diesel and gasoline engine exhausts and some
nitroarenes,'' Vol. 46, Monographs on the evaluation of carcinogenic
risks to humans, International Agency for Research on Cancer, World
Health Organization, 1989.
\18\ ``Diesel fuel and exhaust emissions: International program
on chemical safety,'' World Health Organization, 1996.
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Benzene. Benzene is an aromatic hydrocarbon which is present as a
gas in both exhaust and evaporative emissions from motor vehicles.
Benzene in the exhaust expressed as a percentage of total organic gases
(TOG), varies depending on control technology (e.g., type of catalyst)
and the levels of benzene and aromatics in the fuel, but is generally
about four percent from gasoline engines. The benzene fraction of
gasoline evaporative emissions also depends on control technology
(i.e., fuel injector or carburetor) and fuel composition (e.g. benzene
level and Reid Vapor Pressure or RVP) and is generally about one
percent.
The EPA has recently reconfirmed that benzene is a known human
carcinogen by all routes of exposure (including leukemia at high,
prolonged air exposures), and is associated with additional health
effects including genetic changes in humans and animals and increased
proliferation of bone marrow cells in mice.\19\ Respiration is the
major source of human exposure. Long-term exposure to high levels of
benzene in the air has been shown to cause cancer of the tissues that
form white blood cells. Among these are acute nonlymphocytic leukemia,
chronic lymphocytic leukemia and possibly multiple myeloma (primary
malignant tumors in the bone marrow). A number of adverse noncancer
health effects, blood disorders such as preleukemia and aplastic
anemia, have also been associated with low-dose, long-term exposure to
benzene. People with long-term exposure to benzene may experience
harmful effects on the blood-forming tissues, especially the bone
marrow. Many blood disorders associated with benzene exposure may occur
without symptoms.
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\19\ ``U.S. EPA, Carcinogenic Effects of Benzene: An Update,''
National Center for Environmental Assessment, Washington, D.C. 1998.
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OSHA recently conducted an industrial hygiene survey to examine
park employee exposures during winter

[[Page 76801]]

at Yellowstone National Park.\20\ They reported exposure to benzene
above the NIOSH recommended exposure levels (REL) of 0.10 ppm. Since
exhaust emission benzene levels generally decrease as HC emissions
decrease, we expect new emission control technology to substantially
reduce ambient benzene levels.
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\20\ ``U.S. Department of Labor, Industrial Hygiene Survey of
Park Employee Exposures During Winter Use at Yellowstone National
Park,'' February, 2000.
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1,3-Butadiene. 1,3-butadiene is formed in engine exhaust by
incomplete combustion of fuel. It is not present in evaporative and
refueling emissions, because it is not present in any appreciable
amount in gasoline fuel. 1,3-butadiene accounts for 0.4 to 1.0 percent
of total exhaust TOG, depending on control technology and fuel
consumption. Nonroad mobile sources contribute 15.2 percent to the 1,3-
butadiene inventory (baseline NTI).
The Environmental Health Committee of EPA's Scientific Advisory
Board (SAB), in reviewing the draft document, issued a majority opinion
that 1,3-butadiene should be classified as a probable human
carcinogen.21,22 The Agency has revised the draft Health
Risk Assessment of 1,3-butadiene based on the SAB and public comments.
The draft Health Risk Assessment of 1,3-butadiene will undergo the
Agency consensus review, during which time additional changes may be
made prior to its public release and placement on the Integrated Risk
Information System (IRIS).
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\21\ ``U.S. EPA Health Risk Assessment of 1,3-Butadiene,'' EPA/
600/P-98/001A, February 1998.
\22\ ``An SAB Report: Review of the Health Risk Assessment of
1,3-Butadiene,'' EPA-SAB-EHC-98, August 1998.
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Formaldehyde. Nonroad mobile sources contribute 23 percent to the
formaldehyde inventory (baseline NTI). EPA has classified formaldehyde
as a probable human carcinogen based on evidence in humans and in rats,
mice, hamsters, and monkeys.\23\ Epidemiological studies in
occupationally exposed workers suggest that long-term inhalation of
formaldehyde may be associated with tumors of the nasopharyngeal
cavity, nasal cavity and sinus. Formaldehyde exposure also causes a
range of noncancer health effects, including irritation of the eyes
(tearing of the eyes and increased blinking) and mucous membranes.
Sensitive individuals may experience these adverse effects at lower
concentrations than the general population. In persons with bronchial
asthma, the upper respiratory irritation caused by formaldehyde can
precipitate an acute asthmatic attack.
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\23\ ``U.S. EPA Assessment of health risks to garment workers
and certain home residents from exposure to formaldehyde,'' Office
of Pesticides and Toxic Substances, April 1987.
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The OSHA industrial hygiene survey at Yellowstone, described above,
reported exposure to formaldehyde at 0.033 ppm, which is above the
NIOSH recommended exposure level of 0.016 ppm.
Acetaldehyde. Nonroad mobile source emissions are responsible for
27 percent of the total acetaldehyde inventory (Baseline NTI).
Acetaldehyde is classified as a probable human carcinogen and humans
are exposed by inhalation, oral, and intravenous routes. The primary
acute effect of exposure to acetaldehyde vapors is irritation of the
eyes, skin and respiratory tract. At high concentrations, irritation
and pulmonary effects can occur, which could facilitate the uptake of
other contaminants.
Acrolein. Nonroad mobile source emissions are responsible for 11
percent of the total acrolein invenory (Baseline NTI). Acrolein is
extremely toxic to humans when inhaled, with acute exposure resulting
in upper respiratory tract irritation and congestion. The Agency has
developed a reference concentration for inhalation (RfC) of acrolein of
0.02 micrograms/m\3\. Although no information is available on its
carcinogenic effects in humans, EPA considers acrolein a possible human
carcinogen based on laboratory animal data.\24\
---------------------------------------------------------------------------

\24\ ``U.S. EPA Integrated Risk Assessment System (IRIS),''
Office of Health and Environmental Assessment, Cincinnati, OH, 1993.
---------------------------------------------------------------------------

4. Carbon Monoxide (CO)
Carbon monoxide (CO) is a colorless, odorless gas produced through
the incomplete combustion of carbon-based fuels. Carbon monoxide enters
the bloodstream through the lungs and reduces the delivery of oxygen to
the body's organs and tissues. The health threat from CO is most
serious for those who suffer from cardiovascular disease, particularly
those with angina or peripheral vascular disease. Healthy individuals
also are affected, but only at higher CO levels. Exposure to elevated
CO levels is associated with impairment of visual perception, work
capacity, manual dexterity, learning ability and performance of complex
tasks.
Several recent epidemiological studies have shown a link between CO
and premature morbidity (including angina, congestive heart failure,
and other cardiovascular diseases). Several studies in the United
States and Canada have also reported an association of ambient CO
exposures with frequency of cardiovascular hospital admissions,
especially for congestive heart failure (CHF). An association of
ambient CO exposure with mortality has also been reported in
epidemiological studies, though not as consistently or specifically as
with CHF admissions. EPA is reviewing these studies as part of the CO
Criteria Document process.
The toxicity of CO effects on blood, tissues and organs have also
been topics of substantial research efforts. Such studies provided
information for establishing the NAAQS for CO. The current primary
NAAQS for CO are 35 parts per million for the one-hour average and 9
parts per million for the eight-hour average. There are currently 17
designated CO nonattainment areas, with a combined population of 31
million. EPA estimated that emissions from nonroad gasoline engines and
vehicles have increased by 24 percent from 1980 to 1998.\25\
---------------------------------------------------------------------------

\25\ U.S. EPA (March 2000). ``National Air Pollutant Emission
Trends, 1900-1998,'' Office of Air Quality and Standards.
---------------------------------------------------------------------------

In addition to concerns related to air quality standards for broad
areas, exhaust emissions from indoor applications can cause CO
poisoning from individual human exposure. These engines (for example,
engines used in forklifts) routinely operate in warehouses and
production facilities. Unregulated industrial SI engines frequently
have exhaust CO concentrations over 30,000 ppm (3 percent). The maximum
allowable time-weighted average 8-hour workplace exposure set by the
Occupational Safety and Health Administration is 50 ppm. Manufacturers
in some cases may adjust engine calibration for somewhat lower CO
emission levels. Also, engines used indoors are often fueled with LPG,
which typically has lower CO exhaust concentrations than gasoline-
fueled engines. However, improper maintenance or poor calibrations can
lead to even higher levels than the 30,000 ppm level noted above from
any industrial SI engine.
The typical snowmobile, which utilizes a two-stroke engine,
produces significantly more CO than a modern automobile on a unit of
work basis. There has been an increasing concern that snowmobile
emissions in and around some national parks are reaching significant
levels. During the winters of 1994-95 and 1995-96, studies were
conducted at Yellowstone, Flagg Ranch, and Grand Teton National Park
which indicated that snowmobile tourists are potentially exposed to
significant CO

[[Page 76802]]

levels.\26\ While the studies did not record official exceedances of
the CO NAAQs, levels near and in some cases above the 35 ppm NAAQS
standard were observed. These measurements were not considered NAAQS
exceedances because sampling methods and measurement locations did not
meet the criteria for NAAQS measurements. However, the measurements
were reported to be scientifically valid and an indication of
potentially significant exposure to CO.
---------------------------------------------------------------------------

\26\ Exposure to Snowmobile Riders to Carbon Monoxide, Park
Science Volume 17--No. 1, National Park Service, U.S. Department of
the Interior.
---------------------------------------------------------------------------

A study of snowmobile rider exposure conducted at Grand Teton
National Park showed that CO levels when trailing a single snowmobile
at distances of 25-125 feet at speeds of 10-40 mph ranged from 0.5-23
ppm, with a maximum level of 45 ppm (as compared to the current NAAQS
for CO of 35 ppm).\27\ Since snowmobile riders typically travel in
large groups, the riders towards the back of the group are likely to
experience significantly higher exposures to CO. An additional
consideration is that the risk to health from CO exposure increases
with altitude, especially for un-acclimated individuals. Therefore, a
park visitor who lives at sea level and then rides his or her
snowmobile on trails at high-altitude is more susceptible to the
effects of CO than local residents. In addition, the OSHA industrial
hygiene survey mentioned earlier reported a peak CO exposure of 268 ppm
for a Yellowstone employee, in exceedance of the NIOSH peak recommended
exposure limit of 200 ppm.
---------------------------------------------------------------------------

\27\ Snook and Davis, 1997, ``An Investigation of Driver
Exposure to Carbon Monoxide While Traveling Behind Another
Snowmobile.''
---------------------------------------------------------------------------

The U.S. Coast Guard reported cases of CO poisoning caused by
recreational boat usage.\28\ These Coast Guard investigations into
recreational boating accident reports between 1989 to1998, show that 57
accidents were reported, totaling 87 injuries and 32 fatalities, that
involved CO poisoning. We believe that controlling CO emissions from
marine engines could provide some benefits to boaters.
---------------------------------------------------------------------------

\28\ Summarized in an e-mail Phil Cappel of the U.S. Coast Guard
to Mike Samulski of the U.S. Environmental Protection Agency,
October 19, 2000.
---------------------------------------------------------------------------

C. National Emissions Inventory

We have estimated the contribution of the sources included in this
ANPRM to the nationwide emissions inventories for the 2000 and 2007
calendar years, as shown in Table II-1.\29\
---------------------------------------------------------------------------

\29\ Inventory data is further provided in Tables 1 and 2 of the
Final Finding (see footnote 4).

Table II-1.--Estimated Nationwide Annual Emission Levels
[in thousand short tons (percent of mobile source inventory)]
--------------------------------------------------------------------------------------------------------------------------------------------------------
NOX HC CO PM
-------------------------------------------------------------------------------------------------------
Tons Percent Tons Percent Tons Percent Tons Percent
--------------------------------------------------------------------------------------------------------------------------------------------------------
Year 2000:
Nonroad Sources in ANPRM.................... 371 2.8 822 11.0 7,15 9.0 8.4 1.2
7
Highway Motorcycles......................... 22 0.2 21 0.3 147 0.2 0.4 0.1
-------------------------------------------------------------------------------------------------------
Year 2000 Total......................... 393 3.0 843 11.3 7,30 9.2 8.8 1.3
4
Year 2007:
Nonroad Sources in ANPRM.................... 444 4.3 870 16.6 7,53 9.7 9.2 1.5
6
Highway Motorcycles......................... 25 0.2 26 0.5 171 0.2 0.5 0.1
-------------------------------------------------------------------------------------------------------
Year 2007 Total......................... 469 4.5 896 17.1 7,70 9.9 9.7 1.6
7
--------------------------------------------------------------------------------------------------------------------------------------------------------

III. Recreational Vehicles

A. Background

1. What Recreational Vehicles Would be Included in This Rulemaking?
The vast majority of vehicles that fall into the land-based
recreational vehicles category are snowmobiles, off-highway motorcycles
(e.g., dirt bikes), and all terrain vehicles (ATVs).\30\ The engines
used in these vehicles are a subset of nonroad SI engines.\31\ Engines
used in recreational vehicles include both Small SI (at or below 19 kW)
and Large SI engines (above 19 kW). These engines, however, were
excluded from our Small SI program (for lawn mowers, chain saws, etc.)
because they have different design characteristics and usage patterns
than other engines in the Small SI category. This suggests that the
recreational engines covered by this ANPRM should be tested differently
than Small SI engines. We would similarly expect to treat them
separately from our Large SI engine program (discussed later in this
ANPRM). We therefore request comment on whether engines used in
recreational vehicles should be tested and regulated differently from
other small and Large SI engines.
---------------------------------------------------------------------------

\30\ ATVs are typically four-wheeled vehicles that are straddled
by the operator.
\31\ Almost all recreational vehicles are equipped with SI
engines. Any diesels used in these applications must meet our
nonroad diesel engine standards.
---------------------------------------------------------------------------

In our rulemaking regulating Small SI engines (defined as nonroad
SI engines below 19 kW), we established criteria that effectively
excluded the types of engines used in the recreational vehicles listed
above.\32\ These criteria, such as normal range of operating engine
rpm, can greatly affect the basic engine design and the opportunities
for emissions control. 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 engines
used in go carts would typically be covered by the Small SI standards.
Engines used in golf carts are also typically included in the Small SI
program due to their design and

[[Page 76803]]

operating characteristics being similar to lawnmower-type applications.
---------------------------------------------------------------------------

\32\ See 40 CFR 90.1(b)(5) for the list of criteria.
---------------------------------------------------------------------------

There may be other types of recreational vehicles that should be
included in the recreational vehicles program in addition to
snowmobiles, off-highway motorcycles, and ATVs. For example, some small
mopeds or motor scooters could be included in the program depending on
their characteristics.\33\ We are interested in information and request
comment about other types of vehicles that may exist so that we may
consider them in developing our proposals.
---------------------------------------------------------------------------

\33\ The definition of motor vehicle excludes ``any vehicle that
cannot exceed a maximum speed of 25 miles per hour over level, paved
surfaces'' (see 40 CFR 85.1703(a)(1)). Such vehicles are therefore
considered nonroad vehicles.
---------------------------------------------------------------------------

There may be some uncertainty surrounding the use of
``recreational'' in distinguishing between vehicle types and in
determining which set of standards a vehicle or engine must meet. ATVs,
for example, may have some utility aspects to their use. We request
comment how to best differentiate among engines types. We could
establish a definition for ``recreational'', for example, based on the
primary intended use of the vehicle model. Under such an approach,
vehicles primarily intended for utility or work use by the manufacturer
would be part of either the Small or Large SI programs, as applicable.
We could also differentiate engines based solely upon engine design and
operating characteristics without regard to usage; this option might
eliminate potential confusion over whether a particular engine should
be appropriately certified as a ``recreational'' or ``utility'' engine.
Hobby engines. The Small SI rule categorized engines used in model
cars, boats, and airplanes as recreational engines and exempted them
from the Small SI program.\34\ Historically, we have exempted hobby
engines from our regulations. The nonroad diesel engine final rule
exempted hobby engines due to feasibility, testing, and compliance
concerns related to regulating such small engines. Also noted in the
nonroad diesel engine rule, because hobby engines are very small with
very low power output relative to other nonroad engines and have low
annual usage rates, they contribute very little to emissions
inventories.\35\ We request comment on how to proceed for SI hobby
engines, including data and information that would allow us to further
consider the potential for establishing standards for them or for
exempting them from this rule.
---------------------------------------------------------------------------

\34\ 80 FR 24292, April 25, 2000.
\35\ 63 FR 56971, October 23, 1998.
---------------------------------------------------------------------------

2. Who Makes Recreational Vehicles?
Based on industry information available to us, the recreational
vehicle industry appears to be dominated by eight manufacturers. Of
these eight manufacturers, seven of them manufacture a combination of
two or more of the three recreational vehicle sub-categories: off-
highway motorcycles, ATVs, and snowmobiles. For example, there are four
major companies that manufacture both off-highway motorcycles and ATVs.
There are three major companies that manufacture ATVs and snowmobiles
and one major company that manufactures all three. These eight
companies represent approximately 95 percent of all domestic sales of
recreational vehicles.
We are aware of five major companies that dominate sales of off-
highway motorcycles. Four of these companies, Honda, Kawasaki, Suzuki,
and Yamaha, are long established, major corporations that manufacture a
number of products including highway and off-highway motorcycles. They
have dominated the off-highway motorcycle market for over thirty years.
The fifth major company, KTM, is also long established but has had a
major impact in domestic sales over the last 10 to 15 years. These five
companies account for approximately 90 to 95 percent of all domestic
sales for off-highway motorcycles. There are also several relatively
small companies that manufacture off-highway motorcycles, many of which
specialize in racing or competition machines.
Based on available industry information, four major manufacturers,
Arctic Cat, Bombardier (also known as Ski-Doo), Polaris, and Yamaha,
account for approximately 99 percent of all domestic snowmobile sales.
The remaining percent comes from very small manufacturers who tend to
specialize in unique designs or racing machines. The ATV sector has the
broadest assortment of major manufacturers. With the exception of KTM,
all of the companies noted above for off-highway motorcycles and
snowmobiles are significant ATV producers. These seven companies
represent over 95 percent of total domestic ATV sales. The remaining 5
percent come from importers who tend to import inexpensive, youth-
oriented ATVs from China and other Asian nations.
3. What Types of Engines Are Used in the Vehicles?
The engines used in recreational vehicles tend to be small, air- or
liquid-cooled, reciprocating Otto-cycle engines that operate on
gasoline.\36\ They are designed to be used in vehicles, where engine
performance is characterized by highly transient operation, with a wide
range of engine speed and load capability. Maximum engine speed is
typically well above 5,000 rpm. Also, the vehicles are equipped with
transmissions to ensure performance under a variety of operating
conditions.
---------------------------------------------------------------------------

\36\ Otto cycle is another name for a spark-ignition engine
which utilizes a piston with homogenous external or internal air and
fuel mixture formation and spark ignition.
---------------------------------------------------------------------------

These engines can be separated into two-stroke and four-stroke
designs. The distinction between two-stroke and four-stoke engines is
important for emissions because two-stroke engines tend to emit much
greater amounts of unburned hydrocarbons (HC) and particulate matter
(PM) than four-stroke engines of similar size and power. Two-stroke
engines also have greater fuel consumption resulting in poorer fuel
economy than four-stroke engines, but they also tend to have higher
power output per unit displacement, lighter weight, and better cold
starting performance. These advantages combined with a simple design
and lower manufacturing costs tend to make two-stroke engines a popular
choice as the power unit for recreational vehicles. Currently,
snowmobiles use two-stroke engines almost exclusively, whereas about 63
percent of all off-highway motorcycles (predominantly in high
performance, youth, and entry-level bikes) and 12 percent of all ATVs
sold in the United States use two-stroke engines. Engine displacement
for off-highway motorcycles and ATVs typically range from 50 cubic
centimeters (cc) to 500 cc for two-stroke engines, and 50 cc to 650 cc
for four-stroke engines. Snowmobile engines range from 100 cc to over
1,000 cc.
The basis for the differences in engine and exhaust emissions
performance 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

[[Page 76804]]

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
only occur once every two revolutions of the crankshaft. In a two-
stroke engine, on the other hand, combustion occurs in 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. The loss of part of the fuel out of the exhaust during
scavenging is one of the major reasons for the 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.
4. What Are the Pollutants of Interest for Each Type of Vehicle?
Recreational vehicles utilizing two-stroke engines, such as
snowmobiles and some models of off-highway motorcycles and ATVs, emit
significant quantities of fine particulate matter (PM), unburned
hydrocarbons (HC), and carbon monoxide (CO). Recreational vehicles
utilizing four-stroke engines, such as some models of off-highway
motorcycles and most ATVs, also emit significant quantities of CO,
however, they tend to emit considerably lower levels of HC and PM than
their two-stroke counterparts. Both engine types emit oxides of
nitrogen ( NOX). Two-stroke engines tend to emit very low
levels of NOX whereas four-stroke engines emit greater
quantities, similar to four-stroke HC emission levels. Exhaust
hydrocarbon emissions also include significant quantities of toxic air
contaminants including benzene, formaldehyde, acetaldehyde, and 1,3
butadiene. The most important source of recreational vehicle emissions
is the engine exhaust, but HC emissions are also produced from the
crankcase in four-stroke engines, by evaporation from the fuel system,
and by vapor displacement during refueling.
5. What Programs Are in Place in California and Elsewhere To Control
Emissions from Recreational Vehicles?
California established standards for off-highway motorcycles and
ATVs which took effect in January 1997 (1999 for vehicles with engines
of 90 cc or less). The standards, shown in Table III-1, are based on
the highway motorcycle chassis test procedures. Manufacturers may
certify ATVs to optional standards, also shown in Table III-1, which
are based on the utility engine test procedure.\37\ This is the test
procedure over which Small SI engines are tested. The stringency level
of the standards was based on the emissions performance of 4-stroke
engines and advanced 2-stroke engines equipped with a catalytic
converter. California anticipated that the standards would be met
initially through the use of high performance 4-stroke engines.
---------------------------------------------------------------------------

\37\ 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 Air Resources Board (Docket A-2000-01, document II-D-06).

Table III-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 NOX CO PM
----------------------------------------------------------------------------------------------------------------
Off-highway motorcycle and ATV standards (g/km)............. a 1.2 ........... 15 ...........
----------------------------------------------------------------------------------------------------------------
HC + NOX CO PM
----------------------------------------------------------------------------------------------------------------
Optional standards for ATV engines below 225 cc (g/bhp-hr).. a 10.0 300 ...........
Optional standards for ATV engines below 225 cc (g/bhp-hr).. a 12.0 300 ...........
Optional standards for ATV engines at or above 225 cc (g/bhp- 300 ...........
hr)........................................................ a 10.0
----------------------------------------------------------------------------------------------------------------
a Corporate-average standard.

California revisited the program in the 1997 time frame because a
lack of certified product from manufacturers was reportedly creating
economic hardship for dealerships. The number of certified off-highway
motorcycle models was particularly inadequate.\38\ In 1998, California
revised the program, allowing the use of uncertified products in off-
highway vehicle recreation areas with regional/seasonal use
restrictions. Currently, noncomplying vehicles can be legally sold in
California and used in attainment areas year-round and in nonattainment
areas during months when exceedances of the state ozone standard are
not expected. For enforcement purposes, certified and uncertified
products are identified respectively with green and red stickers. Only
about one-third of off-highway motorcycles sold in California are
certified. All certified products are powered by 4-stroke engines.
---------------------------------------------------------------------------

\38\ Initial Statement of Reasons, Public Hearing to Consider
Amendments to the California Regulations for New 1997 and Later Off-
highway Recreational Vehicles and Engines, State of California Air
Resources Board, October 23, 1998 (Docket A-2000-01, II-D-08).
---------------------------------------------------------------------------

California has not adopted standards for snowmobiles. In addition,
EPA is not aware of emission control programs for nonroad recreational
vehicles that have been adopted in other countries.

[[Page 76805]]

B. Technology

1. What Are the Baseline Technologies and Emissions Levels?
As discussed earlier, recreational vehicles are equipped with
relatively small high performance two- or four-stroke engines that are
either air- or liquid-cooled.\39\ The fuel system used on these engines
are almost exclusively carburetors. Two-stroke engines lubricate the
piston and crankshaft by mixing oil with the air and fuel mixture. This
is accomplished by most contemporary 2-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. In fact, because performance and
durability are such important qualities for recreational vehicle
engines, they all 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.
---------------------------------------------------------------------------

\39\ 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
would range from 0.05 liters to 0.65 liters.

Table III-2.--Typical Range of Exhaust Emissions for Recreational Vehicles
----------------------------------------------------------------------------------------------------------------
Recreational vehicle type Engine type HC CO NOX PM Units
----------------------------------------------------------------------------------------------------------------
Snowmobiles.................. 2-stroke...... 67-200 196-400 0.3-1.62 0.7-6.1 g/hp-hr
Off-highway Motorcycles/ATVs. 2-stroke...... 8-26 16-37 0.01-0.1 0.002-0.025 g/km a
4-stroke...... 0.4-3 7-50 0.03-0.2 0.006-0.025 g/km
----------------------------------------------------------------------------------------------------------------
a Emission measurement for motorcycles is in grams per kilometer rather than grams per mile because the
motorcycle industry, as well as Federal, California, and international motorcycle emission standards use
``Systeme International d'Unites'' or SI units, which measure distance in kilometers rather than miles.

2. What Technology Approaches Are Available To Control Emissions?
A number of approaches are available to control emissions from
recreational vehicles. The simplest approach would consist of
modifications to the base engine, fuel system, cooling system, and
recalibration of the air and fuel mixture. These could, for example,
consist of changes to valve timing for four-stroke engines, changing
from air to liquid cooling, and the use of advanced carburetion
techniques and electronic fuel injection (EFI) in lieu of traditional
carburetion systems. Other approaches could include using an oxidation
catalyst alone or in conjunction with secondary air. The engine
technology that may have the most potential for maximizing emission
reductions from two-stroke engines is the use of direct fuel injection
(DI). 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. The use of oxidation catalysts in conjunction with
direct injection could potentially reduce emissions even further.
Finally, because four-stroke engines emit significantly lower levels of
HC than two-stroke engines, the conversion of two-stroke engine
technology to four-stroke engine technology could be a desirable
approach.
We request comment as to whether there are any other approaches to
emission reduction for recreational vehicles that have not been
discussed here. We are interested in information on feasibility, cost
and corresponding emission reduction potential, and other issues
associated with the above and other technologies. Specifically, we
request comment on the effectiveness and durability of oxidation
catalysts for these applications, the cost, corresponding emission
reductions, and feasibility of direct fuel injection for two-stroke
engine applications, and the cost and feasibility of switching from 2-
stroke to 4-stroke engines. Any data on engines similar to those used
in recreational equipment using these technologies is also requested.
3. What Level of Control May Be Feasible?
Calibration changes and engine modifications can reduce HC and CO
emissions somewhat, in the range of 10 to 30 percent. While the precise
level of control anticipated from recreational vehicles is not yet
known, further HC reductions in the 70 to 90 percent range may be
achievable from current two-stroke engines. We expect that the bulk of
the HC reductions would occur through the elimination of scavenging
losses, with additional reductions possible through the use of an
oxidation catalyst. Because four-stroke engines already have low HC
emissions relative to two-stroke engines, we would expect more modest
HC reductions from four-stroke engines as a result of new emission
standards. Control strategies that would reduce HC emissions would also
generally reduce PM and toxics. This is especially true for 2-stroke
engines where high levels of PM and toxics are the result of scavenging
losses.
We believe that similar levels of control can be expected for CO
emissions as for HC emissions. The bulk of CO reductions will come from
improvements to the fuel system, either through enleanment (i.e., less
fuel) of the air and fuel mixture, from now on referred to as A/F
ratio, or the improvement of fuel atomization (i.e., smaller fuel
droplets), with additional reductions possible through the use of an
oxidation catalyst.40-41 Such strategies are also likely to
reduce HC and PM emissions as well.
---------------------------------------------------------------------------

\40-41\ Fuel atomization refers to the size of individual fuel
droplets. The smaller the fuel droplet is, the better it is
combusted or burned.
---------------------------------------------------------------------------

The NOX levels emitted from recreational vehicles,
especially for those equipped with two-stroke engines, are very low
since most recreational vehicles typically operate using a ``rich''
calibration (i.e., with excess fuel) for performance and durability
purposes.
Some emission reduction techniques such as changes in engine design
and calibration aimed at reducing HC and CO emissions may increase
NOX. However, we expect that any increases

[[Page 76806]]

resulting from HC and CO standards would be minimal. To ensure
continued low NOX performance, we request comment on the
appropriateness of setting a capping standard for NOX
emissions or combining NOX control with HC by setting a HC +
NOX standard.
We request comment on the various strategies available to reduce
emissions and the costs and potential corresponding emissions
reductions of those strategies.

C. Standards and Program Approaches

Although off-highway motorcycles, ATVs, and snowmobiles are all
categorized as recreational vehicles, we expect to establish separate
emissions standards for them. The most fundamental reason for varying
standards is that the operating characteristics are significantly
different. Since we typically try to evaluate and control emissions
performance under normal operating conditions, it is likely we will
adopt different test procedures for the different applications. Also,
the level of stringency and the timing of the standards may vary
depending on the types of emissions control technology available, cost
impacts, industry make-up, and other factors that we must consider in
establishing the program. We request comments on the appropriateness of
separate emission standards for off-highway motorcycles, ATVs, and
snowmobiles.
Generally, we will be considering what level of emissions control
is appropriate and the lead-time necessary for manufacturers to achieve
those emissions reductions. There are a number of approaches that have
been used in programs for other nonroad engines to effectively reduce
emissions, both in the near term and long term. These approaches often
incorporate some level of flexibility into the program which has
allowed manufacturers to achieve lower overall emissions levels,
perhaps at less cost. Programs have been tailored to the particulars of
the engine categories and industries being regulated to achieve the
overall goals of the program.
In many programs, we have established either a single set (tier) of
standards, or multiple tiers of standards that progressively achieve
further reductions over a number of years. We have also established
corporate-average standards, including declining fleet averages where
manufacturers must calculate fleet average emissions levels and reduce
those emissions incrementally each year over several model years. Also,
in some cases, standards have been phased-in over a number of years as
a percentage of sales or by an engine characteristic such as size. Some
programs also include averaging, banking and trading, discussed below
in section III.C.4.
We have used such mechanisms, in part, to allow manufacturers to
plan their research, development, and product introductions. Such
program approaches may allow manufacturers to achieve long-term
emission reductions that may not otherwise be achievable. For example,
a declining fleet average approach over several years may provide near
term reductions and also provide manufacturers with lead-time needed to
employ advanced technology in an orderly and efficient manner. Also,
averaging can provide flexibility by allowing manufacturers to certify
some engines to levels above the standard as long as excess emissions
are offset by sales of engines certified to emissions levels below the
standard. However, such approaches may be of limited value to small
businesses or companies offering only a few models and may not be
justified for some programs. We encourage you to consider these
approaches, and any others, in commenting on the standards discussed
below.
1. Off-Highway Motorcycles and ATVs
We are considering establishing HC, NOX, and CO
standards for off-highway motorcycles and ATVs. PM is discussed
separately in section III.C.3, below. We expect the largest benefit in
terms of reducing the ozone precursors NOX and HC to come
from reducing HC emissions from two-stroke engines. Two-stroke engines
have very high HC emissions levels. Baseline NOX levels are
relatively low for engines used in these applications and therefore
initial NOX standards may serve to cap NOX
emissions. CO reductions can be expected from both 2-stroke and 4-
stroke engines, as CO levels are somewhat similar for the two engine
types.
HC Standard. In the current off-highway motorcycle and ATV market,
consumers can choose between 2-stroke and 4-stroke models in most sizes
and categories. Each engine type offers unique performance
characteristics. Some manufacturers specialize in 2-stroke or 4-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 emissions
standards overall. As described in the previous section, a variety of
technological approaches appear promising to control HC emissions. HC
emissions can be reduced substantially by switching from 2-stroke to 4-
stroke engines. The California emissions control program for off-
highway vehicles provides ample data on the emissions performance
capability of 4-stroke engines in off-highway motorcycles and ATVs.
Off-highway motorcycles certified to California standards for the 2000
model year have HC certification levels ranging from 0.4 to 1.0 g/km.
The motorcycles have engines ranging in size from 50 cc to 650 cc and
none of these motorcycles are equipped with catalyst technology.
Technologies are also available for the two stroke engine that may
reduce HC emissions levels to near those provided by 4-stroke engines.
Technologies such as direct fuel injection and catalysts have been
applied to 2-stroke engines used in other applications, such as
personal watercraft and outboard marine engines, in response to
emissions control requirements. However, only vehicles equipped with 4-
stroke engines have been certified to the California standards. Two
stroke models are sold in California, but only under California's
allowance for the sales and use of uncertified products under certain
circumstances (discussed above in section III.A.5).
In determining what standards to propose, we will be carefully
examining the feasibility and cost of both 2-stroke and 4-stroke
technologies. Modest reductions (up to 30 percent) appear feasible
through the use of engine modifications and calibration changes. We are
also interested in approaches that would reduce HC emissions
substantially (for example, 75 to 90 percent) from baseline 2-stroke
engine levels. Clearly, switching to 4-stroke engines achieves this
goal and some manufacturers would likely choose this approach to
meeting such standards.
However, some manufacturers may want an opportunity to achieve HC
reductions through the use of advanced technology 2-stroke engines.
This approach may require more time and investment in research and
development than switching to 4-stroke engines entirely, but could
result in more cost effective emissions control in the long term. Also,
if such engines were developed, consumers may benefit from having a
variety of engine types from which to choose. We request comment on
whether EPA should attempt to set standards in a manner that would
encourage the development of clean 2-stroke technology, and if so, how
that objective could best be accomplished.
We request comments on the appropriate level of HC control for off-

[[Page 76807]]

highway motorcycles and ATVs. We are interested in perspectives on
whether an HC standard should be based on the capabilities of 4-stroke
or 2-stroke engine emissions control technologies. We are also
interested in comment on establishing separate standards for the two
engine types. In making their recommendations, commenters are
encouraged to consider the level of emission reductions currently
achieved under the California emissions control program, described
above, and the need and opportunity for further emissions reductions.
Commenters are also encouraged to consider the benefits of aligning
highway motorcycle HC standards, discussed in section IV below, with
the HC standards for off-highway motorcycles and ATVs. We are
interested in comments on technology, cost, corresponding emission
reduction potential, necessary lead-time, phase-in, and performance
implications, including supporting rationale and data, where possible.
Commenters are also invited to address the cost and corresponding
emissions reductions of various other potential strategies.
As described above, we may propose averaging approaches such as
corporate-average standards and averaging, banking, and trading. We
request comment on the appropriateness of averaging ATVs and off-
highway motorcycles together, assuming they are required to meet the
same standards, or standards of similar stringency. Comments on other
aspects of averaging as it might apply to HC compliance are requested
(for example, averaging recreational vehicles with other engines
identified in this document).
NOX standard. While the focus of the program would be on
achieving HC reductions, we also request comment on the need for and
appropriateness of NOX control for these engines. We are
considering standards in the form of HC plus NOX. We would
expect a small NOX increase when going from uncontrolled
two-stroke engines to engine designs which meet new emissions
standards. This NOX increase is due to engine efficiency
improvements and emission control strategies available for 2-stroke
engines. A NOX plus HC standard recognizes this trade-off.
Also, 4-stroke engines typically have higher NOX emissions
than 2-stroke engines.
When we established the HC plus NOX standard for
personal watercraft, we adjusted the level of the standard to account
for the inclusion of NOX. We request comment on this
approach for establishing an HC plus NOX limit for
motorcycles and ATVs. We also request comment on how much of an
adjustment to the standard is needed to account for NOX
emissions or what level would be appropriate for a NOX cap.
We also request comment on a NOX plus HC standard in the
context of averaging approaches for compliance. Finally, we request
comment on the cost implications and corresponding emission reduction
potential of NOX control strategies.
CO standard. We expect to establish a CO limit for motorcycles and
ATVs, along with HC and NOX standards. We will be
considering the levels established by California for these vehicles and
the standards for highway motorcycles. We request comment on what level
of CO control would be appropriate for these vehicles, considering
costs (and other statutory factors). We also request comment on whether
or not the CO standard should be established as a separate technology
driver or based on the performance of technologies likely to be needed
to achieve low HC emissions levels. We request comment on the cost
implications and corresponding emission reduction potential of CO
control strategies. As with HC and NOX, we are interested in
the usefulness of considering averaging approaches for CO emissions
compliance.
Test procedures. The form and numeric level of the standards depend
on the test procedures and test cycle over which emissions are
measured. As described above in section III.A.5., California off-
highway motorcycle and ATV standards are based on the highway light-
duty vehicle test procedure (the FTP). This is a chassis-based test
procedure, which requires the vehicle to be tested rather than only the
engine.
Some manufacturers have noted that they do not currently have
chassis-based test facilities capable of testing ATVs. California
provides manufacturers with the option of certifying ATVs using the
engine-based, utility engine test procedure (SAE J1088), and most
manufacturers use this option for certifying their ATVs. Manufacturers
have facilities to chassis test motorcycles and therefore California
does not provide an engine testing certification option for
motorcycles. Manufacturers have noted that requiring chassis-based
testing for ATVs would require them to invest in additional testing
facilities which can handle ATVs, since ATVs do not fit on the same
roller(s) as motorcycles used in chassis testing.
Currently, for off-highway motorcycles and ATVs, we are planning to
use the FTP test cycle, as it appears to be the best available test
cycle for these vehicles. We will be carefully examining the potential
pros and cons of using an engine-based test procedure for ATVs and
request comment on this issue. We request comment on whether or not the
approach taken by California is suitable for the federal program,
including the use of the above test procedures and their effectiveness
in ensuring in-use emissions reductions.
We are particularly interested in comments on the use of the
utility engine cycle for ATVs, and whether or not a different engine-
based test cycle, such as the one being considered for snowmobiles
(discussed below), may be more suitable. The utility engine cycle is a
5-mode steady-state test cycle which includes testing at only one
engine speed (85 percent of rated speed). Such a test procedure is
appropriate for engines used in lawn and garden applications, but may
not be appropriate for engines used in vehicle applications. The
snowmobile engine test procedure is also a 5-mode steady-state test
procedure but the engine speed varies by mode along with torque. We
believe this is generally more representative of how an engine behaves
in a vehicle application.
2. Snowmobiles
Emissions standards established by EPA through this rulemaking will
be the first for snowmobiles. Unlike off-highway motorcycles and ATVs,
there are no emissions standards for snowmobiles in California to use
as a point of reference. Snowmobiles are almost entirely equipped with
two-stroke engines which have very high HC and CO emission levels. Our
focus for snowmobiles will be to reduce those emission levels.
NOX emissions are much less of a concern because of the
seasonal nature of snowmobile use and low baseline levels.
CO standard. CO emissions may be a larger concern for snowmobiles
than for off-highway motorcycles and ATVs due to their high CO
emissions levels and the general concern of high ambient CO level in
some areas during cold weather. In initial discussions with the
International Snowmobile Manufacturers Association (ISMA),
manufacturers have suggested setting standards that would result in CO
reductions of 10 to 30 percent, phased in over model years 2004-2006.
As described in section III.B. above, promising technologies are
available which have the potential to reduce emissions to significantly
lower levels. These technologies go beyond minor engine modifications
and calibration changes and may require additional lead time to
implement. However, with

[[Page 76808]]

appropriate lead time, further CO emission reductions may be reasonably
achievable.
We will be evaluating potential technologies and the costs of those
technologies during the development of our proposal for snowmobiles. We
will consider the timing of the standards in the context of the level
of stringency we propose, recognizing that more lead-time would likely
be needed to apply and prove-out the application of certain advanced
technologies. Also, as described above, we will consider the value of
implementation flexibilities such as averaging and phase-in schedules
in allowing manufacturers to meet more stringent standards in an
orderly manner. We request comment on what level of CO emissions
control is feasible and appropriate for snowmobiles, on the cost and
corresponding emissions reduction potential of various strategies, on
the lead time needed to achieve new standards, and on the usefulness of
implementation flexibility in meeting the standards.
HC standard. As mentioned in section II, we received comments
indicating that HC control for snowmobiles for purposes of reducing
ozone may not be necessary due to their seasonal use. However, we
believe that there may be a need to control HC emissions from
snowmobiles. In particular, even if we accept the commenters' argument
regarding ozone, HC emissions may result in increased exposure to air
toxics. As discussed in section II, hydrocarbons are made up of
numerous components, some of which have been identified as toxic air
pollutants.
We anticipate that many of the technology approaches available to
manufacturers to reduce CO emission levels would also reduce HC
emissions levels. The two-stroke engines used in snowmobiles have very
high HC levels and we believe that establishing standards to reduce
those levels would be appropriate. Manufacturers have suggested an HC
reduction of up to 30 percent by 2008, in addition to the 30 percent
reduction in CO by 2006, discussed above. As with CO, we believe
technology is likely to be available to achieve a greater degree of
control, especially with several years lead time or phase-in.
Reductions in CO and HC of 70 percent or more may be feasible.
We request comment on what level of HC emissions control is
feasible and appropriate for snowmobiles, the cost and corresponding
emissions reductions associated with such levels of emissions control,
the lead time needed to achieve new standards, and the usefulness of
implementation flexibility in meeting the standards. In particular, we
request comment on the appropriateness of requiring any control of HC
for snowmobiles given the seasonal nature of their use versus air toxic
concerns for riders.
Test Procedures. Snowmobile manufacturers, in conjunction with
Southwest Research Institute, have developed a test procedure for
measuring snowmobile emissions.\42\ This effort was undertaken due to
increasing interest in snowmobile engine emission levels and a lack of
a test procedure based on a representative duty-cycle. The test cycle
is a 5-mode steady-state cycle, with different engine speed and torque
points chosen and weighted to reflect in-use engine operation (see
table below). The study also found that the utility engine cycle
(J1088), which had previously been used, was not appropriate for
snowmobiles.
---------------------------------------------------------------------------

\42\ ``Development and Validation of a Snowmobile Engine
Emission Test Procedure,'' Christopher W. Wright and Jeff J. White,
SAE Paper 982017.

Table III-3.--Snowmobile Engine Test Cycle
(SAE paper 982017)
----------------------------------------------------------------------------------------------------------------
mode 1 2 3 4 5
----------------------------------------------------------------------------------------------------------------
normalized speed............................... 1.0 0.85 0.75 0.65 idle
normalized torque.............................. 1.0 0.51 0.33 0.19 0
Weight, %...................................... 12 27 25 31 5
----------------------------------------------------------------------------------------------------------------

We request comment on the use of this test procedure as the basis
of future snowmobile standards. This test procedure appears to be the
best currently available for snowmobiles, but we request comment on the
need for additional tests or test modes to ensure in-use emissions
control. For example, idle CO emissions have been highlighted as a
particular concern for snowmobiles and we request comment on the need
for additional emphasis on idle CO emissions within the test procedure.
3. The Need for PM Standards
As discussed in section II, Air Quality, we are very concerned
about current high particulate matter levels in snowmobile exhaust.
High PM levels are primarily attributable to the use of traditional 2-
stroke engines. PM emissions are also a concern for off-highway
motorcycles and ATVs to the extent that 2-stroke engines are used in
those applications.
We believe that the technology changes that would be needed to
significantly reduce CO and HC levels, such as direct injection or 4-
stroke engines, may also dramatically reduce PM levels. If HC and CO
standards were established at a level only requiring minor
modifications to the engines, PM could remain a problem for snowmobiles
and a PM standard may be necessary. We request comment on whether or
not we should establish a PM standard for snowmobile engines and what
level of stringency would be appropriate. We also request comment on
the cost implications (equipment costs, etc.) associated with measuring
PM as part of the certification procedure.
4. Averaging, Banking, and Trading
Depending on the structure of the proposed program, the level of
stringency of the proposed standards, and other considerations, we may
propose averaging, banking, and trading provisions (ABT) for
recreational vehicles/engines. We have established ABT programs in many
of our engine-based emissions control programs in cases where we have
set standards that require significant technology changes. The ABT
programs allow manufacturers

[[Page 76809]]

to earn credits by introducing clean engines sooner than required or by
certifying engines to levels below the standards. Manufacturers may use
the credits to certify engines to levels above the standards in the
same model year (averaging), keep the credits for use in a later model
year (banking), or transfer the credits to another manufacturer
(trading).
In some cases, we have not established ABT programs because we
believed the standards we were adopting were achievable without the
additional flexibility. In such cases, EPA found that the added
complexity inherent in having an ABT program, both for EPA and the
manufacturers, would outweigh the potential benefits of the program.
ABT can be beneficial in providing incentive to manufacturers for
the early introduction of new technologies, allowing certain engine
families to be trail blazers for new technology. This flexibility can
allow us to consider a more stringent program than would otherwise be
appropriate under CAA section 213. The programs also provide
flexibility to manufacturers for product planning and can provide
opportunity for more cost effective introduction of product lines. ABT
is tailored to meet the specific needs of standards and programs being
established. This is necessary to avoid issues such as windfall credits
and the potential of stockpiling credits which could result in a
significant delay of the standards being adopted or future standards
not yet considered. We request comment on integrating ABT into the
programs for recreational vehicles. We are interested in comment on the
scope of ABT, including any particular issues we should consider in
developing such a program, and whether or not credit trading among
different vehicle types should be allowed.

D. Additional Program Considerations

1. Competition Off-Highway Motorcycles
Currently, a large portion of off-highway motorcycles are marketed
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,\43\ although some
high performance enduro models \44\ are marketed for competition use.
These high performance motorcycles are largely powered by 2-stroke
engines, though some 4-stroke models have been introduced in recent
years.
---------------------------------------------------------------------------

\43\ 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
manueverability. 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.
\44\ 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.
---------------------------------------------------------------------------

When used for competition, motocross motorcycles are mostly
involved in closed course or track racing. Other types of off-highway
motorcycles 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 sections 216 (10) and (11) exclude engines and
vehicles ``used solely for competition'' from nonroad engine and
vehicle regulations. For purposes of past nonroad engine emissions
control regulatory programs (for example, the nonroad CI, recreational
marine, and Small SI programs), EPA has defined the term ``used solely
for competition'' 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.
If retained for the recreational vehicles program, the above
definition may be useful for identifying certain models that are
clearly used only for competition. For example, there are motorcycles
identified as ``observed trials'' motorcycles which are designed
without a standard seat because the rider does not sit down during
competition. This feature would make recreational use unlikely. Most
motorcycles marketed for competition, however, do not appear to have
physical characteristics that constrain their use to competition.
Without such distinguishing characteristics, determining that a vehicle
is used solely for competition becomes more challenging.
Manufacturers have recommended that EPA use the definition for
competition motorcycle that EPA has previously established for purposes
of exempting motorcycles from its noise regulations, as follows:
Competition motorcycle means any motorcycle designed and marketed
solely for use in closed course competition events.\45\
---------------------------------------------------------------------------

\45\ 40 CFR 205.151(a)(3).
---------------------------------------------------------------------------

Manufacturers further recommended that closed course competition
include ``any organized competition event covering a closed, repeated,
or defined route intended for easy viewing of the route by spectators.
Such events could include, but are not limited to, motocross, enduro,
hare scrambles, observed trials, short track, dirt track, drag race,
hill climb, ice race, and land speed trials * * *''. Manufacturers
recommended that EPA require labels designating the vehicles for
competition use only.\46\
---------------------------------------------------------------------------

\46\ ``MIC Recommended Definitions for Pending EPA Recreation
Vehicle Exhaust Emissions Proposal,'' Motorcycle Industry Council,
Draft, June 1, 2000. Docket A-2000-01.
---------------------------------------------------------------------------

Based on confidential sales information, we believe that vehicles
designated for competition by manufacturers could exceed 50 percent of
total sales under their recommended approach. We believe that many
``competition'' style motorcycles are likely to also be used, at least
by many end users, primarily or often for recreational riding. Section
216(10) of the Act excludes from the definition of nonroad engines
vehicles used solely for competition. We are concerned that the
approach suggested by manufacturers may be overly broad and therefore
would not meet the conditions of this exclusion.
In a recent rulemaking for marine diesel engines, we addressed
competition engines by providing exclusions for engines used in
professional competitions only.\47\ Engines used for amateur
competition or occasional competition are not excluded under that rule.
The exclusion is available both to manufacturers and to someone
modifying an engine for professional competition use (normally, we
would prohibit someone from making changes to a certified engine in
ways that adversely affect emissions control). This would be one
possible

[[Page 76810]]

approach to address the competition use issue for recreational
vehicles.
---------------------------------------------------------------------------

\47\ 64 FR 73305, December 29, 1999.
---------------------------------------------------------------------------

We are very interested in receiving input on the competition
exemption issue described above. We request comment on ways the program
can be established to provide an exclusion for motorcycles used solely
for competition, consistent with the Act, without excluding vehicles
that are often used for other purposes. Ideally, the program can be
established in a way that provides reasonable certainty at time of
certification. However, approaches could include reasonable measures at
time of sale or in-use that would provide assurance that the
competition exemption is being applied appropriately. We request
information and data on the use of off-highway motorcycles for
competition and recreation that would inform the rulemaking process.
2. Crankcase Emissions From Recreational Vehicles
We will be considering proposing the elimination of crankcase
emissions from recreational vehicles. Venting the crankcase to the
atmosphere is a source of HC emissions that has been cost effectively
controlled in many other engine applications. Rather than venting these
emissions to the atmosphere, they can be routed back to the engine for
combustion. We believe that any effect on exhaust emission levels due
to the additional hydrocarbons which are routed to the engine through
the crankcase emissions control system can be substantially reduced, if
not eliminated, through the recalibration of the engine. We are not
aware of any issues particular to closing the crankcase on engines used
in recreational vehicles. California has required the elimination of
crankcase emissions on off-highway motorcycles and ATVs as part of
their program. We request comments on the costs, emission reductions,
and any other issues associated with requiring the elimination of
crankcase emissions from recreational vehicles.
3. Compliance Measures
Along with emissions standards, we will be considering requirements
to ensure in-use compliance with those standards over the useful life
of the recreational vehicles/engines. The goal of these measures would
be to promote high quality engine design, production, and in-use
emissions performance. Compliance programs typically include
certification, production line testing, and in-use testing components.
Under these programs, manufacturers must submit data and other
information prior to introducing the engine into commerce certifying
that the engine meets applicable standards, and there is the ability to
verify compliance through engine testing at the production line and in-
use. We expect to examine the structure and effectiveness of compliance
programs contained in other nonroad emissions control programs in
determining what types of measures would be most appropriate for
recreational vehicles.
Because of similarities in the applications, engine
characteristics, and production volumes, we will carefully consider
whether the compliance programs for recreational vehicles should be
modeled after the programs adopted to control emissions from marine
outboard engines and personal watercraft.\48\ Some manufacturers making
these marine products also make recreational vehicles, and are
therefore familiar with the structure of the marine engines program.
---------------------------------------------------------------------------

\48\ 61 FR 52088, October 4, 1996.
---------------------------------------------------------------------------

We encourage interested parties to review the compliance program in
place for outboard engines and personal watercraft and provide input to
EPA on the potential for applying the same types of compliance measures
to these other recreational vehicles. In particular, we are interested
in comments on requirements for manufacturer production line and in-use
testing. For outboard engines and personal watercraft, the production
line testing program requires manufacturers to test engines as they
leave the production line. This process is used to provide a quality
control check on the manufacturer's production processes to ensure that
engines are routinely assembled in a way such that they continue to
meet emission performance requirements when coming off the assembly
line. The manufacturer in-use testing program requires manufacturers to
select engines from the in-use fleet and test a portion of their engine
families each year. These requirements focus resources on ensuring in-
use compliance and are key components to the overall compliance program
we have established for recreational marine engines.
4. Consumer Modifications
We are aware that consumers sometimes modify engines and exhaust
systems on their recreational vehicles. Some of these changes are done
to enhance operating performance. Others are to maintain optimal
performance under varying operating conditions (i.e., changes in
altitude, weather, etc.). We request information on the types of
modifications that are common for the different types of recreational
vehicles and any information on their impact on emission performace. We
are especially interested in those modifications that would affect the
emissions performance of the vehicle, and could be considered tampering
under the Act for engines certified to emissions standards. We also
request information that would help us better understand how common
these practices are for the different types of vehicles. Understanding
the scope of these practices will help us establish standards and
program requirements that achieve in-use emissions reductions.
5. Useful Life
For highway motorcycles, we currently have three distinct useful
life categories that are based on engine displacement. The useful life
for all three categories are five years or 12,000 km, 18,000 km, or
30,000 km depending on which category the motorcycle falls under.
California has established a useful life of 5 years or 10,000 km for
off-highway motorcycles and ATVs. For some of our nonroad engine
regulations, we have based useful life on time (i.e., hours). We
request information that would help us determine the most appropriate
method for establishing useful life for recreational vehicles. For
example, a certain number of hours may be appropriate for snowmobiles
and possibly ATVs, whereas a useful life similar to that used for
highway motorcycles or California off-highway motorcycles may be more
appropriate for off-highway motorcycles. We request comment on what the
appropriate useful life levels and values would be for the various
types of recreational vehicles.
6. Consumer Labeling
We request comment on the potential for a consumer labeling program
for recreational vehicles. We are also interested in comment on this
topic for recreational marine engines, as discussed in section V.E.10.
The purpose of a labeling program would be to educate consumers so that
they could make informed decisions concerning engine emissions when
they purchase a recreational vehicle. One example of a consumer
labeling program is the California Air Resources Board's requirement
that personal watercraft and outboard engines sold in California
starting in 2001 be labeled as either low, very-low, or ultra-low
depending on their emission levels.
We request comment on the merit and cost of including such a
program in our proposal for recreational vehicles and

[[Page 76811]]

whether the program should be voluntary or mandatory. We also request
comment on programmatic aspect of labeling such as the content of the
label, the number of tiers that would be useful in distinguishing among
recreational vehicle models, and the pollutant(s) that should be used
in establishing those tiers. Finally, we request comment on any other
appropriate incentives for introducing new clean technologies that may
be available.

IV. Highway Motorcycles

A. What Is a Highway Motorcycle, and Who Makes Them?

Motorcycles come in a variety of two-and three-wheeled
configurations and styles. For the most part, however, they are two-
wheeled self-powered vehicles. Federal regulations currently define a
motorcycle as ``any motor vehicle with a headlight, taillight, and
stoplight and having: two wheels, or three wheels and a curb mass less
than or equal to 680 kilograms (1499 pounds).'' (See 40 CFR 86.402-
86.478). Vehicles that otherwise meet the motorcycle definition but
have engine displacements less than 50 cubic centimeters (cc)
(generally, youth motorcycles, most mopeds, and some motor scooters)
are currently not covered by federal regulations. Also currently
excluded are motorcycles which, ``with an 80 kg (176 lb) driver, * * *
cannot: (1) Start from a dead stop using only the engine; or (2) Exceed
a maximum speed of 40 km/h (25 mph) on level paved surfaces' (e.g.,
some mopeds). Most scooters and mopeds have very small engine
displacements and are typically used as short-distance commuting
vehicles. Motorcycles with larger engine displacement are more
typically used for recreation (racing or touring) and may travel long
distances. Both EPA and California regulations further sub-divide
highway motorcycles into classes based on engine displacement. Table
IV-1 shows how these classes are defined.
The currently regulated highway category includes motorcycles
termed ``dual-use'' or ``dual-sport,'' meaning that their designs
incorporate features that enable them to be reasonably competent on and
off road. Dual-sport motorcycles generally can be described as street-
legal dirt bikes, since they tend to bear a closer resemblance in terms
of design features and engines to true off-highway motorcycles than to
highway cruisers or sport bikes. However, another category of
motorcycle, referred to as ``enduros,'' are very similar in appearance
to dual-sport motorcycles, but are typically equipped with higher
performance engines and have traditionally been categorized as nonroad
motorcycles and not been subject to the highway emission standards.
Therefore, we request comment as to how we can better determine which
motorcycles are street-legal and which are not.
Throughout this ANPRM the term ``highway motorcycle'' is intended
to include all motorcycles covered by the current federal regulations;
thus, dual-sport motorcycles are included in this definition. We
currently believe that all highway motorcycle engines sold in the U.S.,
including those that power dual-sport motorcycles, are four-stroke
engines.

Table IV-1.--Motorcycle Classes
------------------------------------------------------------------------
Engine displacement (cubic
Motorcycle class centimeters)
------------------------------------------------------------------------
Class I................................ 50--169.
Class II............................... 170--279.
Class III.............................. 280 and greater.
------------------------------------------------------------------------

Highway motorcycles are dominated by larger engines, with engine
displacements exceeding 1000 cc for the most powerful ``superbikes.''
According to the Motorcycle Industry Council (MIC), in 1998 there were
about 5.4 million highway motorcycles in use in the United States (only
565,000 of these were dual-sport), more than three-fourths of which had
an engine displacement of over 449 cc.\49\ Sixty percent had an engine
displacement greater than 749 cc. Inclusion of the dual-sport
motorcycles in this figure tends to skew the numbers somewhat, even
despite the fact that their total numbers are relatively small, because
their dirt bike heritage leads them to be weighted towards smaller
engines. According to the MIC data, three-fourths of dual-sport
motorcycles had an engine displacement of less than 350 cc, whereas
two-thirds of the remaining motorcycles (those purely designed for road
use) had a displacement of over 749 cc. Total sales in 1998 of highway
motorcycles was estimated to be about 411,000, or about 72 percent of
motorcycle sales. About 13,000 of these were dual-sport motorcycles.
The remaining 28 percent of sales were strictly off-highway
motorcycles, which are currently unregulated.
---------------------------------------------------------------------------

\49\ ``1999 Motorcycle Statistical Annual,'' Motorcycle Industry
Council.
---------------------------------------------------------------------------

We are aware of a half-dozen companies, Honda, Harley Davidson,
Yamaha, Kawasaki, Suzuki, and BMW, which account for near 95 percent of
all motorcycles sold. Dozens of other minor players make up the
remaining few percent. Based on available information, over half of all
motorcycles sold in 1998 were made by Honda and Harley Davidson, with
the two companies maintaining almost equal market shares of about 25
percent each.

B. What Is the Regulatory History?

1. Environmental Protection Agency Regulations
In 1974 EPA issued an advance notice of proposed rulemaking that
discussed the possible implementation of emission controls for highway
motorcycles for the first time and requested comment on a number of
issues. Taking into account the comments received on the ANPRM, EPA
issued an NPRM the following year for the control of exhaust and
crankcase emissions from new motorcycles. The proposal addressed
standards for HC, CO, and NOX, proposing a set of interim
standards for 1978 and 1979 and final standards equivalent to the
light-duty vehicle standards in effect at that time. The NPRM was
followed by a Final Rule promulgated in 1977 (42 FR 1126, Jan. 5, 1977)
which established interim standards effective for the 1978 and 1979
model years and ultimate standards effective starting with the 1980
model year. The interim standards ranged from 5.0 to 14.0 g/km HC
depending upon engine displacement,

[[Page 76812]]

while the CO standard of 17.0 g/km applied to all motorcycles. The 1980
standards, which were more lenient than those that were proposed and
which lacked a NOX standard, are essentially those that
remain in effect today. While the final standards did not differ based
on engine displacement, the useful life over which these standards must
be met ranged from 12,000 km (7,456 miles) for Class I motorcycles to
30,000 km (18,641 miles) for Class III motorcycles. These standards
were updated in 1989 to include methanol-fueled motorcycles starting
with the 1990 model year, then again in 1994 to include natural gas-
fueled and liquefied petroleum gas-fueled motorcycles starting with the
1997 model year. Crankcase emissions from motorcycles are also
prohibited. There are no current federal standards for evaporative
emissions from motorcycles. The current federal standards are shown in
Table IV-2.

Table IV-2.--Current Federal Exhaust Emission Standards for Motorcycles
------------------------------------------------------------------------
Engine size HC (g/km) CO (g/km)
------------------------------------------------------------------------
All........................................... 5.0 12.0
------------------------------------------------------------------------

2. Regulation by the California Air Resources Board
Motorcycle emission standards in California were originally
identical to the federal standards that applied to the 1978 through
1981 model years. The definitions of motorcycle classes used by
California continue to be identical to the federal definitions.
However, California has revised their standards several times to bring
them to their current levels. In 1982 the standards were modified to
reduce the HC standard from 5.0 g/km to 1.0 or 1.4 g/km, depending upon
engine displacement. California adopted an evaporative emission
standard of 2.0 g/test for 1983 and later model year motorcycles. In
1984 California amended the regulations for 1988 and later model year
motorcycles to further lower emission standards and provide additional
compliance flexibility to manufacturers. The 1988 and later standards
could be met on a corporate-average basis, and the larger (Class III)
bikes (280 cc and above) were split into two separate categories: 280
cc to 699 cc and 700 cc and greater. These are the standards being met
in California today. Like the federal standards, there are no currently
applicable NOX standards for highway motorcycles in
California. Under the corporate-averaging scheme, no individual engine
family is allowed to exceed a cap of 2.5 g/km. Like the federal
program, California also prohibits crankcase emissions.

Table IV-3.--Current California Highway Motorcycle Exhaust Emission
Standards
------------------------------------------------------------------------
Engine size (cc) HC (g/km) CO (g/km)
------------------------------------------------------------------------
50-279.......................................... 1.0 12.0
280-699......................................... 1.0 12.0
700 and above................................... 1.4 12.0
------------------------------------------------------------------------

In 1998 the California Air Resources Board (CARB) proposed new
standards for Class III highway motorcycles that would take effect in
two phases--a ``Tier 1'' to start with the 2004 model year, followed by
a ``Tier 2'' that would take effect starting with the 2008 model year.
These standards were finalized with minor modifications on November 22,
1999. Existing California standards for Class I and II motorcycles
remained unchanged. As with the current standards, manufacturers will
be able to meet the requirements on a corporate-average basis. Perhaps
most significantly, this recent CARB action brings some level of
NOX control to motorcycles by establishing a combined
HC+NOX standard. No changes were made by the CARB action to
the CO standard, which remains at 12.0 g/km. In addition, CARB is
providing an incentive program to encourage the introduction of
motorcycles compliant with the Tier 2 standard prior to the 2008 model
year. This incentive program allows the accumulation of credits that
manufacturers can use to meet the 2008 standards. Like the federal
program, these standards will also apply to dual sport motorcycles.

Table IV-4.--Tier 1 and Tier 2 California Class III Highway Motorcycle Exhaust Emission Standards
----------------------------------------------------------------------------------------------------------------
HC+NOX (g/
Model year Engine displacement km) CO (g/km)
----------------------------------------------------------------------------------------------------------------
2004 through 2007 (Tier 1)..................... 280 cc and greater..................... 1.4 12.0
2008 and subsequent (Tier 2)................... 280 cc and greater..................... 0.8 12.0
----------------------------------------------------------------------------------------------------------------

California also adopted a new definition of small volume that would
take effect with the 2008 model year. Historically, California had a
definition of small volume that applied to the 1984 through 1987 model
years (5,000 units per model year), but no definition that has applied