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Clean Snowmobiles: Reasons for Change
Table of Contents
Background and Overview
Reasons for Change
Preventing Pollution
Where To Go for Help
Complete List of Links

Essential Links:

Clean Snowmobile Facts
Presents objective and balanced information about all aspects of the debate over snowmobile emission...

High emission levels from snowmobiles have been widely publicized since 1997. Some believe that snowmobile emissions are too high and must be reduced. As a result of a law suit filed by the Sierra Club and others, the United States Environmental Protection Agency (EPA) released draft snowmobile emission standards in September 2001 by court order. These became a final regulation with revisions in September 2002.

Snowmobile Controversy

In the late 1990's the Blue Water Network and other conservation groups filed suit against the Department of Interior and National Park Service to ban snowmobiles from National Parks. As part of the response, snow machines were prohibited from the wilderness core of Denali National Park in 2000. In 1997, law suits were filed by the Friends for Animals, the Greater Yellowstone Coalition, and 60 other conservation groups to ban the grooming of trails that allegedly allowed bison to walk out of Yellowstone Park and be destroyed (due to a ruling under USDA regulations). As a result of the negotiation, the National Park Service completed a Winter use Plans Environmental Statement for Yellowstone and Grand Teton National Parks and the John D. Rockefeller Jr. Memorial Parkway signed January 2001. The decision outlined a plan to phase out the use of recreational snowmobiles in the included parks and parkway in favor of mass transit visitation using snowcoaches.

Implementation of the 2001 rule was later suspended by a Wyoming federal court settlement. The State of Wyoming and International Snowmobile Manufacturers Association (ISMA) accused the Park Service of not using the most current emissions data for winter use vehicles. The Park Service addressed this by developing a Supplemental Environmental Impact Statement with a new rule published in the federal register in December 2003. The Supplement EIS rule limited winter visitation to a predetermined number of cleaner, quieter snowmobiles and snowcoaches so that impacts would be no greater than those of the 2001 mass transit ruling (based on then existing, dirtier snowcoaches). Under the EIS, all aspects of winter use would be monitored and visitation would change depending on how the monitoring data impacted the thresholds set out.

The night before the 2003-2004 winter season was to start, a judge in Washington DC ruled on a suit brought by the Fund for Animals and the Greater Yellowstone Association that the 2003 Supplemental EIS was not legal because it failed to be consistent with the Administrative Policy Act (because NPS did not adequately explain why it reversed itself from 2001). He also stated that the 2003 regulations did not meet NEPA requirments because NPS did not consider a “no grooming” alternative. This effectively meant that the 2001 rule had to be implemented, reducing the number of snowmobiles allowed into the parks by half (

The State of Wyoming then went back to the Wyoming District Court, where the judge re-opened and restated his original ruling that the 2001 NPS rule to phase out snowmobiles was invalid. He also ordered NPS to allow more snowmobiles into the Parks this winter ( The result at this time, is that two different federal judges, one in Wyoming and one in Washington DC, have ruled that two different pieces of federal law are invalid making both the ban of snowmobiles, and the select use of cleaner snowmobiles unlawful. The controversy has left Yellowstone Park gateway communities and park staff reeling (

Environmental assessments relating to snowmobile management are also currently underway in Rocky Mountain National Park in Colorado and Mount Rainier National Park in Washington.

Why Cleaner and Quieter

  • Access to existing snowmobile trails and public lands will be protected if snowmobile pollution is reduced.

  • Snowmobilers will have a more pleasant riding experience if their exposure to snowmobile exhaust emissions is decreased. They are currently exposed to significant levels of pollution from their own vehicles.

  • Rental operators may attract new customers by offering cleaner, quieter snowmobiles for rent. Many people who would otherwise enjoy snowmobiling choose not to ride because they find the fumes and sound levels offensive.

Snowmobile rental operators and outfitters who use ethanol-blend and low-emissions lube oil have cut emissions by 16 to 70 percent, maintenance by at least 60 percent, and have gotten a higher resale on the machines due to cleaner engines and less engine wear. Three-season long demonstration projects have shown that use of these products increases engine life, reduces fuel consumption, and increases power by at least five percent. Rental operators and personal use snowmobilers who use the newer technology and four-stroke machines will save money because of the increase in fuel economy from the 9 to 13 mile per gallon average to the 28 to 40 miles per gallon observed in the fleets in and around Yellowstone.


The Topic Hub™ is a product of the Pollution Prevention Resource Exchange (P2Rx)

The Clean Snowmobiles Topic Hub™ was developed by:

Peaks to Prairies Pollution Prevention Center
Peaks to Prairies Pollution Prevention Center
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Hub Last Updated: 11/26/2012