Industry
- Briggs and Stratton
- Caterpillar
- Consumers Energy Company
- Cummins
- Daimler
- Detroit Diesel Corporation
- DTE Energy
- DTE Energy Resources
- Entergy Nuclear Operations
- Ford Motor Company
- General Motors
- Holtec International
- International
- Lyondell Chemical Company
- Mack
- Midwest Energy
- POET
- Toyota
- We Energies
- White Energy
Trade Associations
- Alliance of Automobile Manufacturers
- American Association for Clean Coal Electricity
- American Coal Council
- American Petroleum Institute
- Association of International Automobile Manufacturers
- Canadian Vehicle Manufacturers Association
- Engine Manufacturers Association
- Growth Energy
- Minnesota Corn Growers
- National Biodiesel Board
- New Fuels Alliance
- Outdoor Power Equipment Institute
- Pacific Ethanol
- Renewable Fuels Association
- U.S. Chamber of Commerce
- Utility Air Regulatory Group
- Western States Petroleum Association
Government
- Environment Canada
- Environmental Protection Agency
- Southeast Michigan Council of Governments
- State of California
- State of Colorado
- State of Michigan
Other
- American Enterprise Institute
- Annapolis Center
- Coordinating Research Council
- Fraser Institute
- Hunton and Williams
- Kirkland and Ellis
- Moore and VanAllen
- New York Law
- Save Our Shoreline