Clean Air Act

The Attorney General plays a leading role in ensuring that the U.S. Environmental Protection Agency (EPA) carries out its duties under the federal Clean Air Act.

Under the previous administration, EPA refused to acknowledge that it had the power to regulate greenhouse gas (GHG) pollution, forcing Massachusetts, California and other states to file suit. In April, 2007, the U.S. Supreme Court ruled that greenhouse gases are "air pollutants" under the Clean Air Act. Read the Supreme Court's decision, pdf. As a result of California’s victory in Massachusetts v. EPA, EPA has begun regulating GHG pollution.

As the Court in Massachusetts v. EPA held, before EPA can regulate GHG emissions from cars and light trucks, EPA must make a determination that climate change is endangering the public health and welfare. At the end of 2009, EPA made this determination, referred to as an "endangerment" determination. EPA’s determination was quickly challenged. The Attorney General has intervened with 17 other states to defend EPA's determination. The case is currently pending.

The Attorney General’s ongoing enforcement work under the Clean Air Act relates not only to regulation of motor vehicles (see “Clean Cars”), but also to other types of vehicles (vessels, aircraft, and non-road vehicles) and power plants. In addition, the Attorney General is supporting EPA in its efforts to “tailor” the requirements of the Clean Air Act so that they better apply to GHG emissions from stationary (non-vehicle) and industrial sources.