Order Code RL31149
CRS Report for Congress
Received through the CRS Web
Snowmobiles: Environmental Standards
and Access to National Parks

Updated December 9, 2004
James E. McCarthy
Specialist in Environmental Policy
Resources, Science, and Industry Division
Congressional Research Service ˜ The Library of Congress

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Snowmobiles: Environmental Standards
and Access to National Parks
Summary
The use of snowmobiles in national parks has been controversial because of
their potential impacts on wildlife and the absence of standards for their emissions
and noise. This report focuses on the latter set of issues.
Congress has addressed snowmobile issues primarily through provisions in
appropriations bills. On November 20, 2004, the House and Senate approved the
conference report on H.R. 4818, the Consolidated Appropriations Act, 2005 (P.L.
108-447). Among its many provisions, the bill establishes winter use rules for
Yellowstone and Grand Teton National Parks, allowing up to 720 snowmobiles daily
in Yellowstone and 140 in Grand Teton, during the 2004-2005 winter season. Earlier
the House voted twice against amendments to Interior Department appropriation bills
that would have prohibited recreational snowmobiling in the two parks.
Most current model snowmobiles emit significant quantities of pollution. In one
hour, a typical snowmobile emits as much hydrocarbon as a 2001 model auto emits
in about two years (24,300 miles) of driving. On November 8, 2002, the
Environmental Protection Agency (EPA) promulgated regulations limiting air
emissions from snowmobiles. These regulations would require a 30% reduction in
emissions beginning in 2006, with more stringent standards (requiring 50%
reductions) effective in 2010 and 2012. The standards were challenged in court by
both the snowmobile manufacturers and environmental groups and were vacated in
part and remanded to EPA in part by the Court of Appeals for the D.C. Circuit, June
1, 2004. EPA has not promulgated any standards for snowmobile noise.
Regarding national parks, the National Park Service has allowed snowmobile
use in 43 units of the park system, in many cases in apparent violation of Executive
Orders from the Nixon and Carter years. Outside of Alaska (where snowmobiles are
permitted in most national parks by law), the most popular national park for
snowmobiling has been Yellowstone, which saw more than 76,000 snowmobile visits
in the 1999-2000 winter season. Under the Clinton Administration, the National
Park Service decided that the emissions and noise from snowmobiling were
incompatible with protecting the park, and promulgated rules that would have phased
out snowmobiles from Yellowstone, with a complete ban beginning in the winter of
2003-2004. The Bush Administration revisited these rules in settlement of a lawsuit,
and announced modifications in March 2003. The modifications would have allowed
950 cleaner, quieter snowmobiles to enter Yellowstone Park per day. These rules and
the Clinton Administration action have been the subject of conflicting court rulings:
a federal court in Wyoming has vacated and remanded the Clinton Administration’s
phaseout, while a federal court in the District of Columbia has vacated and remanded
the Bush Administration rules.
Efforts to reduce snowmobile emissions and noise remain contentious. This
report discusses snowmobile access to the parks, snowmobile emissions, and the new
EPA standards, and concludes with a discussion of legislative proposals in the 107th
and 108th Congresses. It will be updated as events warrant.

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Contents
Snowmobile Use in National Parks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Park Service Policy on Snowmobile Access . . . . . . . . . . . . . . . . . . . . . . . . . 2
Denali National Park . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Yellowstone/Grand Teton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Clean Air Act and Noise Control Act Regulation . . . . . . . . . . . . . . . . . . . . . 7
Snowmobile Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
EPA’s New Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Reaction to the EPA Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Legislative Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
List of Tables
Table 1. National Park Use by Snowmobiles, Winter 1999-2000 . . . . . . . . . . . . . 2
Table 2. EPA and NPS Snowmobile Emission Limits . . . . . . . . . . . . . . . . . . . . 10

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Snowmobiles: Environmental Standards
and Access to National Parks
Proposals by the National Park Service to enforce long-standing policy that
regulates the use of snowmobiles in national parks have raised a number of questions
regarding the current and potential regulation of such vehicles. National Park System
units account for only about 3% of the land mass of the United States and possess
few trails and roads suitable for snowmobiles, compared to areas available on other
federal lands; but — for both proponents and opponents — the question of
snowmobile access to the parks has taken on a far greater importance. To the
snowmobile industry and to many in communities neighboring national parks,
“Snowmobiling is an important part of the economic engine that supports northern
communities, winter tourism.”1 To environmental groups, snowmobiling “is one of
the most environmentally devastating recreational activities permitted by the Park
Service .... resulting in adverse impacts to Park wildlife, air and water quality,
vegetation, Park ecology, and Park users.”2 Underlying the debate are broader
questions concerning regulation of emissions and noise from the vehicles and the
degree to which restrictions may serve as a precedent or stigma affecting snowmobile
and motorized recreation3 use more generally.
Snowmobile Use in National Parks
In recent years, snowmobiles have been allowed access to 43 units of the
National Park System, including such major parks as Yellowstone, Grand Teton,
Rocky Mountain, Acadia, Zion, Mount Rainier, and Sequoia. While numerous park
units have allowed such access, recreational use of snowmobiles is not widespread
in the park system as a whole. The National Park Service (NPS) administers 388
units (parks, seashores, monuments, etc.). Of these, 345 (89%) have not been open
to snowmobiles. Many units are located in climates unsuitable for them or are too
small to be used for such recreation. Others (e.g., Glacier National Park and
Yosemite) have banned snowmobiles since the 1970s. According to the National
Park Service, use of snowmobiles outside of Alaska is mostly concentrated in five
1 Statement of Ed Klim, President, International Snowmobile Manufacturers Association,
at U.S. EPA Public Hearing, Washington, D.C., October 24, 2001.
2 Petition to Prohibit Snowmobiling and Road Grooming in National Parks, submitted to
the National Park Service, January 21, 1999, by Bluewater Network and 60 other
environmental groups. A copy of the petition is attached to the testimony of Sean Smith,
Public Lands Director, Bluewater Network, submitted to the Subcommittee on National
Parks, Historic Preservation and Recreation, Senate Energy and Natural Resources
Committee, May 25, 2000.
3 Motorized recreation includes all-terrain vehicles, off-road motorcycles, and personal
water craft, in addition to snowmobiles.

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CRS-2
units of the park system: Yellowstone National Park, Voyageurs National Park,
Rocky Mountain National Park, Pictured Rocks National Lakeshore, and the John D.
Rockefeller Memorial Parkway (see Table 1).
Table 1. National Park Use by Snowmobiles, Winter 1999-2000
Park Service Unit
Location
Number of Snowmobiles
Entering the Park
Yellowstone National Park
Wyoming
76,571
Voyageurs National Park
Minnesota
35,000
Rocky Mountain National Park
Colorado
27,000
Pictured Rocks National
Michigan
26,000
Lakeshore
John D. Rockefeller Memorial
Wyoming
23,399
Parkway
Sources: National Park Service, National Parks Conservation Association.
Park Service Policy on Snowmobile Access
Although recreational access by snowmobiles has been permitted in these units
of the park system, the Park Service in recent years has concluded that such use has
generally been in violation of Executive Orders 11644 and 11989, issued by
Presidents Nixon and Carter respectively. The Nixon Order directed that use of off-
road vehicles on public lands “be controlled and directed so as to protect the
resources of those lands, to promote the safety of all users of those lands, and to
minimize conflicts among the various uses of those lands.”4 It specified that off-
road vehicle “areas and trails shall be located in areas of the National Park system ...
only if the respective agency head determines that off-road vehicle use in such
locations will not adversely affect their natural, aesthetic, or scenic values,” and it
directed the Park Service to “monitor the effects of the use of off-road vehicles” and
to rescind or limit this use “as necessary to further the policy of this order.”
In January 1999, the Park Service received a rulemaking petition from the
Bluewater Network and 60 other environmental organizations seeking a ban on
snowmobiles from all units of the National Park Service. In response, the Service
surveyed units of the System to assess the extent to which they were complying with
the Executive Orders. According to Interior Department testimony: “The results
graphically demonstrated that the National Park Service was not complying with its
statutory and regulatory mandates.... Consequently, maintaining the status quo with
regard to snowmobiling was simply not an option.”5 On April 27, 2000, the
4Executive Order 11644, “Use of Off-Road Vehicles on the Public Lands,” 37 Federal
Register 2877, February 9, 1972.
5 Statement of Donald J. Barry, Assistant Secretary for Fish and Wildlife and Parks, U.S.
(continued...)

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CRS-3
Department of the Interior and the National Park Service announced that
“snowmobiling for general recreational purposes will be prohibited throughout the
Park System, with a limited number of narrow exceptions.”6 By July 2000, the
Department had backed away from its strict enforcement stance with a clarification:
there would be no snowmobile ban in park units pending a formal rulemaking and
public comment period, and snowmobile practices prior to the April 2000
announcement (i.e., access to more than 40 parks) would continue in place through
the 2000-2001 winter season.7 NPS has taken no further action to enunciate a general
policy.
Since the summer of 2000, the focus has been on Denali National Park in
Alaska and the Yellowstone/Grand Teton area. Both of these areas had been
considered exceptions subject to special consideration even under the April 2000
policy announced by the Park Service. Whether snowmobile access to these parks
will be allowed to continue has generated substantial public interest.
Denali National Park. In Alaska, vast distances, lack of roads, abundant
snow cover, and small dispersed populations make snow machine use ubiquitous.
In general, national parks in Alaska allow snowmobile access under the provisions
of the Alaska National Interest Lands Conservation Act (ANILCA, P.L. 96-487).
However, access to the 2 million acres formerly known as Mt. McKinley National
Park (now the core of Denali National Park) has been an issue. Prior to passage of
ANILCA (1980), snowmobiles had been banned from this park. In 1999, the Park
Service reinstated this policy, banning snowmobiles first on a temporary and later on
a permanent basis.8 Litigation regarding access to Denali was initiated by
snowmobile user groups, but was withdrawn in June 2001, on the assumption that
legislation would be introduced to address the issue. Legislation (H.R. 4677 / S.
2589, 107th Congress) was introduced in the spring of 2002 that would have allowed
access to some portions of the old Park, while continuing the ban elsewhere. No
action was taken on these bills, however, and similar legislation was not introduced
in the 108th Congress.
5(...continued)
Department of the Interior, before the House Committee on Resources, Subcommittee on
National Parks and Public Lands, and the Senate Committee on Energy and Natural
Resources, Subcommittee on National Parks, Historic Preservation, and Recreation, May
25, 2000.
6 U.S. Department of the Interior, Office of the Assistant Secretary, “National Park Service
Puts the Brakes on Escalating Snowmobile Use in the National Park System,” Press Release,
April 27, 2000, p. 2. In addition to Alaska parks and the three Yellowstone area units
discussed below, Voyageurs National Park in Minnesota was also exempted because of the
express authorization of snowmobiles in its enabling legislation.
7 Statement of Denis P. Galvin, Deputy Director, National Park Service before the
Subcommittee on National Parks and Public Lands, House Committee on Resources,
Oversight Hearing on General Issues Involving Access to National Parks, July 20, 2000, p.
2.
8 The temporary closure was instituted on February 3, 1999. The permanent closure was
finalized June 19, 2000, at 65 Federal Register 37863.

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CRS-4
Yellowstone/Grand Teton. The other exception to the National Park
Service’s general policy was the Yellowstone/Grand Teton National Park area. The
NPS had been sued in May 1997 by groups who alleged that the Service was
violating the National Environmental Policy Act, the Endangered Species Act, the
National Park Service Organic Act, and the Yellowstone Act in allowing use of
snowmobiles in the two parks and on the Rockefeller Memorial Parkway (which
links them). The lawsuit was settled within months when the NPS agreed to conduct
an Environmental Impact Study (EIS) of winter use of the parks. Upon completion
of the study, the Clinton Administration promulgated a final rule in January 2001,
banning snowmobiles from Yellowstone, Grand Teton, and the Rockefeller Parkway
beginning in the winter of 2003-2004, but allowing continued visitor access through
the use of “snowcoaches” — guided tour-vans that run on rubber treads.9
Snowmobile manufacturers, represented by the International Snowmobile
Manufacturers Association (ISMA), have suggested that “cleaner, quieter”
snowmobiles — a phrase not initially defined — be allowed continued access to the
parks. Their suggestion found a receptive audience in the Bush Administration. On
June 29, 2001, the Administration responded to a suit filed by ISMA and the State
of Wyoming by agreeing to reopen the decision to ban the vehicles from the three
Yellowstone area units. The Park Service agreed to prepare a Supplemental EIS and
reach a new Record of Decision by November 15, 2002 (a deadline subsequently
extended to March 15, 2003).
The Record of Decision was signed March 25, 2003, and a final rule
implementing it was promulgated December 11, 2003.10 Despite receiving 104,802
comments on the final proposal, 91% of which “believed the proposed regulation
does not adequately protect park resources due to the presence of snowmobiles,”11
the Park Service reversed the ban in favor of daily limits on entrants, emission
standards for the snowmobiles, other access requirements, and an “adaptive
management strategy,” allowing park managers to take remedial action if monitoring
indicates unacceptable impacts from implementation. In explaining its position, the
NPS stated: “We are trying to provide a range of appropriate activities in the parks,
while protecting park resources and values.”12
The new rule would set a daily limit of 950 snowmobile entrance passes for
Yellowstone Park, 115 in Grand Teton National Park, and 400 on Rockefeller
Memorial Parkway.13 On most days, this limit would result in no reduction of
snowmobile users; but on weekends and holidays, when as many as 1,700
snowmobiles have entered the three park units, it could limit the number of entrants.
9 Special Regulations, Areas of the National Park System, 66 Federal Register 7260,
January 22, 2001.
10 Special Regulations, Areas of the National Park System, 68 Federal Register 69268,
December 11, 2003.
11 Ibid., p. 69269.
12 Ibid.
13 Seventy-five of the passes are for the Continental Divide Snowmobile Trail, which lies
in both Grand Teton National Park and the Parkway. These are counted in each unit’s total.

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Snowmobile users would generally be required to be accompanied by trained guides
(although the regulations would allow group members to be as much as 1/3 of a mile
from the guide, and the rule preamble concedes, given the noise of a snowmobile,
that communication is difficult if not impossible even between passengers on the
same machine). To discourage irresponsible behavior, alcohol use by snowmobile
users would be strictly limited.
The machines themselves would be required to achieve a 90% reduction in
hydrocarbon emissions and a 70% reduction in carbon monoxide under the Bush
Administration rules. Noise emissions would be limited to 73 dB(A), which the NPS
estimates is about a 50% reduction compared to conventional snowmobiles. To
implement these provisions, the Yellowstone Park Superintendent released a list of
10 snowmobile models approved for use during the 2003-2004 winter season, on
September 16, 2003.14 (The list was updated on October 6, 2004, and now contains
16 models.15)
A hearing on the new rules was held in the U.S. District Court for the District
of Columbia on December 15, 2003. The rules were vacated and remanded to the
National Park Service by Judge Emmett Sullivan on December 16. The judge held
that there was no evidence in the record to support the Bush Administration reversal
of the previous agency position and that the decision, therefore, was “arbitrary and
capricious.” The court also held that the Supplemental EIS accompanying the
changes was “flatly inadequate” under NEPA and that the snowmobile decision was
“completely politically driven and result oriented.”16 The judge also ordered NPS to
respond to Bluewater Network’s 1999 rulemaking petition (seeking a ban on
snowmobiles in all National Park System units) by February 17, 2004.17 Judge
Sullivan’s decision reinstated the Clinton Administration rule and cut the number of
snowmobiles entering the three Yellowstone area park units in half for the 2003-2004
winter season in preparation for a complete ban in 2004-5.
Both ISMA and the State of Wyoming appealed the court’s ruling. Their
request for a stay of the Clinton-era rules pending resolution of their appeal was
denied by Judge Sullivan in late December 2003 and by a three-judge panel of the
14 [http://www.nps.gov/yell/press/03115.htm].
15 [http://www.nps.gov/yell/planvisit/todo/winter/batlist_current.htm].
16 Fund for Animals v. Norton, 2003 U.S. Dist. LEXIS 22557 (D. D.C. December 16, 2003).
17 NPS denied the petition February 17, 2004, stating that given the differences among
parks, “a service-wide directive to prohibit all forms of recreational snowmobile use in the
National Park System is no longer warranted and ... with requirements for monitoring and
increased use of newer technology snowmobiles, recreational uses can continue to be a part
of the NPS winter experience. This will allow decisions to be made on a park-by-park basis,
relying on the professional judgment of each park’s staff. They will be able to consider the
lessons from Yellowstone, such as the use of Best Available Technology requirements,
guiding requirements, and adaptive management, as well as overall technological
improvements and any other new information, and will then be able to determine whether
any review or revision of their special regulations is needed.” See “Snowmobile Use in the
National Park System,” Memorandum from Assistant Secretary for Fish and Wildlife and
Parks to the Director, National Park Service, February 17, 2004, pp. 4-5.

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Court of Appeals January 13, 2004. Meanwhile, however, the same groups
petitioned the Federal District Court for Wyoming to overturn the Clinton-era rules.
That court responded February 10, 2004, when Judge Clarence Brimmer issued a
temporary restraining order against the Clinton rules and ordered the National Park
Service to develop temporary rules for the remainder of the 2004 winter season. On
February 11, the Park Service issued such rules, allowing 780 snowmobiles to enter
Yellowstone Park each day, an increase of 287 machines. Grand Teton Park and the
Rockefeller Parkway were allowed 140 snowmobiles, an increase of 90. An appeal
of Judge Brimmer’s order was denied by the 10th Circuit Court in Denver on March
10. (The Wyoming court vacated and remanded the Clinton rules on October 14,
2004.)
As a result of the court decisions, snowmobile use in the three parks was
substantially reduced during the 2003-2004 winter season. According to NPS, an
average of 258 snowmobiles entered Yellowstone in January and February 2004, a
reduction of two-thirds from the historic average. In Grand Teton and the
Rockefeller Parkway, the reduction was almost total: through February 10, only about
5 snowmobiles a day entered the two parks. After the February 10 court decision,
this number increased to about 20.18
Another result of the court decisions was that the Park Service began additional
studies to develop new winter use plans. On June 2, 2004, the National Park Service
began additional studies to establish a Temporary Winter Use Plan for 2004-2005
and up to two additional winter seasons.19 During this three-year period, NPS expects
to complete a long-term analysis of the environmental impacts of winter use,
culminating in a permanent decision about snowmobile access. An Environmental
Assessment and proposed Temporary Winter Use Plan were made available for
public review September 7, 2004,20 and final regulations were published November
10, 2004.21
The Temporary Plan would allow 720 snowmobiles per day in Yellowstone, all
commercially guided, and 140 snowmobiles in Grand Teton National Park and the
John D. Rockefeller, Jr., Memorial Parkway. With minor exceptions, all of the
snowmobiles would be required to meet NPS best available technology (BAT)
requirements shown below in Table 2.22 Snowcoaches would also be allowed. NPS
says the combination of snowmobiles and snowcoaches “should provide a viable
18 Yellowstone National Park, “Winter Use Plans Environmental Assessment and Proposed
Rule,” December 6, 2004, p. 2 at [http://www.nps.gov/yell/planvisit/winteruse/].
19 See [http://www.nps.gov/yell/press/0448.htm].
20 69 Federal Register 54072.
21 Department of the Interior, National Park Service, “Special Regulations; Areas of the
National Park System; Final Rule,” 69 Federal Register 65347, November 10, 2004.
Hereafter, “November 2004 Regulations.”
22 The exceptions are primarily for snowmobiles accessing other public lands or private
property by way of specific road or trail segments. See November 2004 Regulations, p.
65351.

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program for winter access to the parks, and ... the opportunity for achieving historic
visitor use levels.”23
Further developments in both the Wyoming and D.C. court cases are expected,
but Congress has insured that any such decisions will not affect the rules for the
2004-2005 winter season. On November 20, 2004, both the House and Senate
approved language, in Section 146 of Title I of Division E of the Consolidated
Appropriations Act, 2005 (H.R. 4818, H.Rept. 108-792), providing that the
Temporary Winter Use Rules described above “shall be in force and effect for the
winter use season of 2004-2005.” The President signed the bill December 8 (P.L.
108-447).
Clean Air Act and Noise Control Act Regulation
In reversing the Clinton Administration rules on Yellowstone access, the
National Park Service set limits on emissions and noise from the snowmobiles that
would be allowed in the three Yellowstone area park units. Simultaneously, EPA has
developed emission limits applicable to all new snowmobiles beginning in 2006.
The following sections of this report describe the EPA proposals and look at the
broader issue of snowmobile emissions.
The Clean Air Act gives EPA authority to regulate emissions from mobile
sources of pollution, including off-road sources such as snowmobiles; but
snowmobiles, until now, have not been subject to any federal or state emission
regulations. Nor have they ever been subject to noise regulations. EPA has authority
under Section 6 of the Noise Control Act of 1972 to regulate noise from
“transportation equipment (including recreational vehicles and related equipment).”
But the Agency’s Office of Noise Abatement and Control was disbanded in 1982,
and EPA has not issued any regulations under the statute in the 22 years since then.
Snowmobile Emissions
Snowmobiles generally run on two-stroke engines — the type of engine that
traditionally has powered outboard motors and lawnmowers. In a two-stroke engine,
fuel enters the combustion chamber at the same time that exhaust gases are expelled
from it. As a result, as much as one-third of the fuel passes through the engine
without being combusted.24 This causes poor fuel economy and high levels of
emissions, particularly hydrocarbons and carbon monoxide. In one hour, a typical
snowmobile emits as much hydrocarbon as a 2001 model automobile emits in 24,300
miles of driving.25 In a day of use, a snowmobile may emit as much hydrocarbon as
23 November 2004 Regulations, p. 65350.
24 In a four-stroke engine (used in automobiles and some newer outboard motors and lawn
mowers, but not generally used in snowmobiles) the combustion chamber takes in fuel,
compresses it, ignites it, and exhausts it in separate cycles, leading to far more complete
combustion and lower emissions, even without the application of emission controls.
25 U.S. EPA, Office of Air and Radiation, Draft Regulatory Support Document: Control of
(continued...)

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CRS-8
an automobile emits in 8-10 years of operation. Snowmobiles also emit as much
carbon monoxide in an hour as a 2001 model auto does in 1,520 miles of driving.
The impact of these emissions on ambient air quality (as described below) is of at
least equal concern as that of hydrocarbons because of the tendency for atmospheric
accumulation of CO in winter.
The hydrocarbons (gasoline) emitted by snowmobiles contain benzene,
formaldehyde, and at least three other substances that are known or suspected human
carcinogens. Carbon monoxide, on the other hand, is a poisonous gas that, at low
levels, can affect those who suffer from cardiovascular disease, such as angina.
In preparing the 2000 Environmental Impact Statement for the decision on
snowmobile access to Yellowstone, the National Park Service measured emissions
from snowmobiles and compared them to other emission sources in the park. The
Service also estimated the concentrations (ambient levels) of carbon monoxide (CO)
and particulate matter (PM) present in the air and compared these concentrations to
air quality standards. The EIS concluded that the 8-hour maximum concentration of
carbon monoxide at the West Yellowstone entrance to the park exceeded the National
Ambient Air Quality Standard for CO by nearly 70% (a concentration of 15.15 parts
per million vs. the standard of 9).26 The analysis also concluded that snowmobiles
accounted for 97.9% of the CO at West Yellowstone during winter months.
Noise has also been an issue. Opponents of allowing snowmobiles in
Yellowstone and other units of the national park system argue that the parks are
special places whose remoteness, beauty, and quiet inspire reflection and awe. The
noise of engines is incompatible with this atmosphere, they argue. Snowmobile
enthusiasts counter that the parks cover vast areas and that snowmobiles are restricted
to a few roads — the same roads traversed by cars, recreational vehicles, and buses
in summer. They also assert that snowmobile use is compatible with the NPS
responsibility to promote visitor use and enjoyment of park resources. Park Service
studies indicate that the sound of snowmobiles can be heard for significantly greater
distances than that of automobiles, however, and is essentially continuous during the
winter at key locations in Yellowstone: snowmobile noise can be heard 95% of the
time by visitors at Old Faithful and 87% of the time at the Grand Canyon of the
Yellowstone.27
25(...continued)
Emissions from Unregulated Nonroad Engines, September 2001, p. I-25, available at
[http://www.epa.gov/otaq/regs/nonroad/proposal/cleanrec.htm#rsd].
26 U.S. Department of the Interior, National Park Service, Winter Use Plans, Final
Environmental Impact Statement for the Yellowstone and Grand Teton National Parks and
John D. Rockefeller, Jr., Memorial Parkway, Volume 1, Chapter 4, p. 224, available at
[http://www.planning.nps.gov/document/yellwinterusevol1.pdf]. Ambient air quality
standards were not exceeded elsewhere in the park.
27 National Park Service, Proposed Rule, Special Regulations, Areas of the National Park
System, 65 Federal Register 79026, December 18, 2000.

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EPA’s New Regulations
Regulations for snowmobile and other non-road engine emissions were signed
by EPA Administrator Whitman September 13, 2002 and appeared in the Federal
Register November 8, 2002.28 As shown in Table 2, the regulations would reduce
both carbon monoxide and hydrocarbon emissions from new snowmobiles a little
more than 30% starting in 2006 and an average of 50% by 2012, with an intermediate
step in 2010. (The regulations do not require any controls on snowmobiles sold
before 2006.) For comparison, Table 2 also shows the Yellowstone-specific
standards that have been imposed by the National Park Service.
According to EPA, the 2006/2007 reductions can be achieved without major
changes in technology, in part because they apply to the average of a manufacturer’s
fleet emissions, rather than to individual machines. This will allow manufacturers
to provide a range of models, some with advanced emission controls and others
without: “While some advanced technologies such as two-stroke direct injection and
four-stroke engines, would be found in some models, many models would still be
equipped with two-stroke engines with relatively minor engine modifications
resulting in minimum emission reductions, while some models may not even have
any emission controls.”29 EPA estimates the cost of these Phase 1 controls at $73 per
snowmobile. Vehicles meeting the standards will be more fuel-efficient, resulting
in an average reduction in operating cost of $57, thus offsetting most of the initial
cost increase.
The 2010 and 2012 standards, which also are fleet averages, can also be met
without eliminating two-stroke engines, according to the Agency. Because two-
stroke engines produce more power than similar size four-strokes and are easy to start
in cold weather, the Agency expects the industry to continue to manufacture mostly
two-stroke engines even in 2012, although many would be modified with direct
injection technology to reduce emissions. According to the Agency, “A potential
scenario for meeting these standards could be a mixture of 50 percent direct injection,
20 percent four-stroke engines, and 30 percent with engine modifications.”30 The
cost of these changes would average an additional $131 per snowmobile in 2010,
28 U.S.EPA, Control of Emissions from Nonroad Large Spark-Ignition Engines, and
Recreational Engines (Marine and Land-Based), Final Rule, 67 Federal Register 68241,
available at [http://www.epa.gov/fedrgstr/EPA-AIR/2002/November/Day-08/a23801.htm].
29 Notice of Proposed Rulemaking: Control of Emissions from Nonroad Large Spark
Ignition Engines and Recreational Engines (Marine and Land-based), Preamble, 66 Federal
Register 51154, October 5, 2001. Further discussion, including the cost estimates, is found
on pp. 51169-51170. The preamble to the final standards says that one scenario for meeting
the 2006/2007 standards would be 15% four-stroke engines, 15% direct injection two-
strokes, 60% conventional two-strokes with improved carburetion, enleanment strategies,
and engine modifications; presumably, the other 10% would have no modifications at all.
Control of Emissions from Nonroad Large Spark-ignition Engines, and Recreational Engines
(Marine and Land-based), Final Rule, as signed September 13, 2002, Preamble, p. 93,
available at [http://www.epa.gov/otaq/regs/nonroad/2002/preamble.pdf].
30 Preamble to the Final Rule, ibid., p. 94.

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Table 2. EPA and NPS Snowmobile Emission Limits
Year
Carbon Mon-
%
Hydrocarbons
%
oxide (CO)
Reduction
(HC)
Reduction
current average
397 g/kW-hr
150 g/kW-hr
2006/2007*
275 g/kW-hr
30.7%
100 g/kW-hr
33.3%
2010
275 g/kW-hr
30.7%
75 g/kW-hr
50%
2012**
200 g/kW-hr*
49.6%
75 g/kW-hr*
50%
Yellowstone/
120 g/kW-hr
70%
15 g/kW-hr
90%
2003 (NPS)
g/kW-hr = grams per kilowatt-hour.
* Half of snowmobiles sold in 2006 must comply with the EPA standards. With a few exceptions, all
snowmobiles sold in 2007 must comply.

** EPA’s 2012 standards allow manufacturers to trade additional reductions in HC for increases in
CO emissions, provided that CO emissions are reduced at least 30%, HC emissions are reduced at least
50%, and the total of HC+CO emissions sums to 100%. Thus, for example, HC reductions of 60%
and CO reductions of 40% would satisfy the requirement, as would HC reductions of 70% and CO
reductions of 30%.
__________________________________________________________________
according to EPA, but the costs would be offset by $286 in fuel savings and
improved performance, so that lifetime costs would actually be $155 lower. The
same is true of the 2012 standards: the added cost of $89 per snowmobile is offset
by $191 in fuel savings and improved performance, according to EPA, for a net
savings of $102 per vehicle.31
The costs of each of the three phases are incremental. Thus, when fully
implemented, the standards would cost an additional $293 per snowmobile,
according to the Agency; lifetime operating costs, however, would decline by $534.
Combining these two factors, the standards would decrease total costs by $241 per
snowmobile when fully implemented.
As compared to the standards EPA proposed in 2001, the final standards were
weakened or made more flexible in three respects, and strengthened in two. First, the
2006 standards are to be phased in, with only 50% of 2006 model snowmobiles
required to meet the standard, and full compliance delayed until the 2007 model year.
Second, the 2010 standard for carbon monoxide remains at the 2006 level of 275
grams per kilowatt-hour; in EPA’s original proposal, it would have been reduced to
200. Third, in 2012, manufacturers will have to meet the standards originally
proposed for 2010, but, within limits, they will be allowed to trade reductions in CO
for additional reductions in hydrocarbons. Thus, reductions of CO may not reach the
31 Ibid., Table IX.B-1, p. 179.

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50% level originally proposed; if they don’t, however, the extra CO emissions would
be offset by additional reductions in hydrocarbons.
The standards were strengthened in two respects. First, EPA added a
permeation emission standard for fuel tanks and hoses. Fuel evaporates through
hoses and through the walls of plastic containers (such as those used as fuel tanks on
snowmobiles). The tank and hose standards require an 85% reduction in plastic fuel
tank permeation emissions and a 95% reduction in fuel system hose permeation
beginning in 2008, in order to lower hydrocarbon emissions from evaporation. The
cost of this standard is estimated at $7 per vehicle, with cost savings of $11.32 The
second, relatively minor, strengthening was the addition of a cap on emissions of
nitrogen oxides (NOx) in 2012. The NOx cap was set at approximately the current
level of emissions. It was added because some of the technologies that might be used
to lower HC and CO could simultaneously increase NOx. To prevent that, the
Agency added a cap at current levels.33
The standards do not include noise limits. While acknowledging that the
Agency has the authority to set noise standards, the proposal stated that “at this time
we do not have funding to pursue noise standards for nonroad equipment that does
not have an existing noise requirement.”34 An Agency source confirmed that the
proposed standards would have essentially no impact on noise.35 Despite receiving
comments from a number of organizations that the standards should address noise,
the Agency restated in its response to public comments that it would not address the
issue, adding that Congress would need to provide appropriations for the Agency to
begin any noise control initiative.36 (As noted, the National Park Service
promulgated noise standards applicable to snowmobiles entering its three
Yellowstone area park units beginning December 17, 2003, under the winter use rule
that was vacated; it restated these standards in its Temporary Winter Use Plan in
effect for the 2004-2005 season.37 According to Park Service estimates, these
standards would require a reduction of about 50% in noise emitted by the affected
snowmobiles, compared to conventional uncontrolled snowmobiles.)
Reaction to the EPA Standards
Both the snowmobile industry and environmentalists have challenged EPA’s
standards in court. On June 1, 2004, the U.S. Court of Appeals for the D.C. Circuit
vacated the standard for nitrogen oxides and remanded the standards for
32 Ibid.
33 Ibid., p. 73.
34 Ibid., p. 135.
35 Personal communication, John Mueller, U.S. EPA Office of Transportation and Air
Quality, September 28, 2001.
36 U.S. EPA, Office of Air and Radiation, Summary and Analysis of Comments: Control of
Emissions from Unregulated Nonroad Engines, September 2002, p.II-78, available at
[http://www.epa.gov/otaq/regs/nonroad/2002/r02023.pdf].
37 36 CFR 7.13(a)(6)(C)(ii), November 2004 Regulations, p. 65361.

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hydrocarbons and carbon monoxide. The court directed EPA “to clarify (1) the
statutory and evidentiary basis of the Agency’s assumption that the standards must
be sufficiently lenient to permit the continued production of all existing snowmobile
models, and (2) the analysis and evidence underlying the Agency’s conclusion that
advanced technologies can be applied to no more than 70% of new snowmobiles by
2012.”38
The International Snowmobile Manufacturers Association (ISMA) has argued
that EPA grossly underestimated the costs of compliance, and that the standards
would lead to the elimination of entry-level snowmobiles from the market. Cleaner,
quieter machines can be made, according to ISMA, but they cost more, are heavier,
and can only be ridden on groomed roads. ISMA estimates that the cleanest four-
stroke engines cost an additional $1,700 (about 30% more than current average
prices). Even modest improvements to two-stroke engines will cost $350-$400 per
machine, according to the Association.39
Bluewater Network, on the other hand — the environmental group most
identified with snowmobile issues — feels the rules should be much stronger.40 In
comments submitted to EPA, Bluewater encouraged the Agency to set standards “that
can only be met using the best available technology, which we believe to be four-
stroke engines with particle traps and three-way catalysts.”41 They also want
mandatory emission labels for the machines, and are disappointed that the Agency
chose not to set noise standards.
Bluewater points to the Clean Snowmobile Challenge, an annual design contest
open to college engineering students and sponsored by the Society of Automotive
Engineers, as demonstrating that machines far cleaner than EPA’s proposed standards
are feasible. The winning entry in the 2001 Challenge reduced CO 78.8% and
unburned hydrocarbons 97.6% and significantly reduced noise, at a cost of $600.42
“If college students are able to build cleaner and quieter machines, surely the billion-
dollar snowmobile industry can do as well,” says Bluewater Public Land Director
Sean Smith.43
Both Bluewater and the snowmobile manufacturers argue that EPA has
misinterpreted the legal authority on which the new standards rely. Bluewater (as
well as other environmental groups and STAPPA, the association representing state
38 Bluewater Network v. EPA, D.D.C., No. 03-1003, June 1, 2004, p. 4.
39 Personal communication, Ed Klim, President, ISMA, September 27, 2001.
40 Personal communication, Sean Smith, Bluewater Network, September 27, 2001. Also see
“Bush Administration Fails to Protect Public Health, Folds to Industry Interests,” Press
Release, September 13, 2002, available at [http://www.bluewaternetwork.org/press_releases/
pr2002sep13_pl_eparule.pdf].
41 Bluewater Network, “Comments on the Environmental Protection Agency’s Advanced
Notice of Proposed Rulemaking, Docket A-2000-01,” p. 2.
42 See “ ‘Clean’ Snowmobile Produces Lower Emissions than the Average Car at SAE
Clean Snowmobile Challenge 2001,” Press Release, April 10, 2001.
43 Personal communication, Sean Smith, Bluewater Network, September 27, 2001.

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air pollution program administrators) argues that EPA is promulgating standards that
are less stringent than the law requires. Section 213(a)(3) of the Clean Air Act
requires the Agency to promulgate standards that “achieve the greatest degree of
emission reduction achievable ... giving appropriate consideration to the cost ... and
to noise, energy, and safety factors....” Four-stroke engine technology, achieving
greater emission reductions than the Agency proposed, is already available, they note
— machines using this technology are on the market. Cost, noise, and energy factors
cannot be used as arguments against adoption of this technology: the lifetime cost of
such engines would be lower than that of current engines, according to the Agency’s
own analysis; the technology uses far less energy, and could be substantially quieter
than current engines. Thus, according to these groups, the Agency’s standards do not
meet the requirements of the act.
Snowmobile and other nonroad-vehicle manufacturers, on the other hand, focus
on Section 213(a)(2) of the act, which ties the Agency’s authority to regulate nonroad
engines to a finding by the Administrator that emissions from such engines or
vehicles “are significant contributors to ozone or carbon monoxide concentrations in
more than 1 area which has failed to attain the national ambient air quality standards
for ozone or carbon monoxide.” EPA addressed this issue before beginning the
process of developing regulations: on June 17, 1994, the Agency made an affirmative
determination that emissions from nonroad engines and vehicles are significant
contributors to ozone, CO, and particulate matter in more than one nonattainment
area.44 On December 7, 2000, the Agency issued a finding that recreational vehicles
(including snowmobiles) are among the specific categories of nonroad vehicles that
contribute to such pollution.45 In its October 5, 2001 Federal Register notice, which
proposed the snowmobile standards, the Agency identified 7 areas in Alaska,
Washington, Colorado, Oregon, and Montana that have significant populations of
snowmobiles and have failed to attain the air quality standard for CO.46
Manufacturers of snowmobiles and other nonroad vehicles note, however, that
carbon monoxide concentrations have declined [chiefly as a result of auto emission
standards] and that none of the 7 areas identified by the Agency has exceeded the CO
standard in recent years, even if they are still formally classified as nonattainment.
CO nonattainment today is essentially a problem in urban “hot spots,” according to
manufacturers, and snowmobiles make no contribution to that problem.47
44 59 Federal Register 31306, June 17, 1994.
45 65 Federal Register 76790, December 7, 2000.
46 66 Federal Register 51105-51107, October 5, 2001. The Preamble to the final rule revised
the list of 7 areas, identifying 6 nonattainment areas in which the Agency believes
snowmobiles are significant contributors to CO concentrations; the Agency added that there
are 6 additional areas that have not been classified nonattainment, but where air quality
monitoring indicates a need for CO control. See Preamble to the Final Rule, previously
cited, p. 18.
47 Statement of Ed Klim, President, ISMA, at EPA Public Hearing, Washington, D.C.,
October 24, 2001.

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Legislative Issues
Members of Congress, both from western and other states, have expressed an
interest in whether there will be continued snowmobile access to national parks.
Four hearings have been held on these issues since the 106th Congress. In November
2004, Congress approved language in the Consolidated Appropriations Act, 2005
(H.R. 4818, H.Rept. 108-792), providing that the Temporary Winter Use Rules
permitting snowmobiles in Yellowstone and Grand Teton National Parks and the
Rockefeller Memorial Parkway “shall be in force and effect for the winter use season
of 2004-2005.”48 Previously, a provision was attached to the FY2001 Consolidated
Appropriations Act (P.L. 106-554) to block the National Park Service from reducing
snowmobile use in any units of the National Park System during the 2000-2001 or
2001-2002 winter seasons.49
In the 108th Congress, Representative Holt has twice attempted to amend Interior
Department Appropriation bills to prohibit spending to manage recreational
snowmobile use in the three Yellowstone area park units except in accordance with
the Clinton Administration rule phasing out snowmobiles. The first such amendment
(H.Amdt. 266 to H.R. 2691) was defeated on a tie vote, 210-210, July 17, 2003. The
second attempt (H.Amdt. 563 to H.R. 4568) was defeated on June 17, 2004, by a vote
of 224-198.
Other legislation has been introduced, but not acted on. In the first session of the
107th Congress, two bills addressing snowmobile use were introduced: S. 365,
introduced by Senator Thomas, to require the National Park Service to allow
continued access to snowmobiles; and H.R. 1465, introduced by Representative Holt,
with the opposite intention — to codify proposed NPS restrictions. The Holt bill
would have set forth a general prohibition on snowmobile access to national parks,
with a limited number of exceptions — for parks in Alaska, for Voyageurs National
Park, for access to private inholdings for owners and their guests, and for designated
routes that provide direct access to public lands open to public snowmobile use in the
vicinity of a park. These restrictions would have applied to all snowmobiles
irrespective of their emission or noise levels. S. 365, on the other hand, assumed that
EPA regulations would result in cleaner, quieter machines. The bill would have
preserved access to the parks for current unregulated snowmobiles for a period of at
least five years after the date of enactment, and would have directed the National
Park Service, at the completion of that period, to propose noise standards for
snowmobile use in national parks “taking into account noise reductions achieved in
conjunction with” EPA’s emission standards. Neither of these bills was reintroduced
in the 108th Congress.
Bills addressing snowmobile issues were also introduced in the second session
of the 107th Congress. In response to the draft Supplemental EIS on access to Grand
Teton, Yellowstone, and the Rockefeller Parkway and the NPS plan to allow
48 Section 146 of Title I of Division E of the Consolidated Appropriations Act, 2005 (H.R.
4818, H.Rept. 108-792).
49 The text of the snowmobile provision can be found in the conference report, H.Rept. 106-
1033, which contains the text of nine bills incorporated by reference in the act.

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snowmobiles access, H.R. 5044 was introduced. This bill, introduced by
Representative Holt, would have banned snowmobile access to the three areas. An
identical bill, S. 2697, was introduced in the Senate by Senator Reid. Bills similar
to these (H.R. 1130 and S. 965) were reintroduced in the 108th Congress by the same
sponsors, but no action was taken on them.
Finally, two bills were introduced during the second session of the 107th
Congress in response to the closure to snowmobiles of a portion of Denali National
Park, discussed previously. Representative Don Young’s H.R. 4677 would have
opened portions of the closed sections of Denali to snowmobiles, but continued to
prohibit use in other portions of the closed sections; a similar bill, S. 2589, was
introduced in the Senate by Senator Murkowski. These bills were not acted on, and
have not been reintroduced.
Conclusions
Despite actions by Congress, EPA, NPS, and the courts, snowmobile issues
remain far from resolved. Congress has provided a temporary resolution of the
Yellowstone access issue, but since it affects only the current winter season, the issue
is likely to return in the 109th Congress. EPA and the National Park Service have
been charged by the courts with revising emission standards and developing
snowmobile access requirements, respectively. Their actions will provide further
opportunities for public and congressional involvement. The courts will also
continue to be involved in these issues, with the continuing legal proceedings over
Yellowstone access, as well as the suits filed regarding emission standards for
snowmobiles.
Public interest in snowmobile issues remains significant: the reopening of the
Yellowstone area Winter Use Plan in early 2003, for example, generated 350,000
public comments. Thus, Congress can be expected to retain an interest in the
resolution of these issues.

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