Endangerment Finding

On April 2, 2007, the Supreme Court ruled in Massachusetts v. EPA that the Clean Air Act gives the Environmental Protection Agency the authority to regulate tailpipe emissions of greenhouse gases. The Court required that the EPA Administrator determine whether emissions from new motor vehicles contribute to air pollution that may endanger public health or welfare; however, the Bush administration failed to exercise this authority.

On April 17, 2009 the EPA Administrator signed a proposed endangerment finding for greenhouse gases. During the 60-day comment period that followed, the EPA received over 380,000 public comments. Following consideration and review of these comments and scientific evidence, the EPA issued final findings on December 7, 2009. The two final findings for greenhouse gases are as follows:

• Six greenhouse gases – carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride – taken in combination endanger both the public health and public welfare of current and future generations
• The combined emissions of these greenhouse gases from new motor vehicles contribute to the greenhouse gas air pollution that endangers public health and welfare under the Clean Air Act.

The threats to public health and welfare from climate change cited by the EPA include increased drought, more heavy downpours and flooding, more frequent and intense heat waves and wildfires, greater sea level rise, more intense storms, and harm to water resources, agriculture, wildlife, and ecosystems.

The issuing of these findings does not in itself require any action by industry or other entities. However, it does allow the EPA to finalize greenhouse gas emissions standards for light-duty vehicles that were proposed in September 2009 along with improved Corporate Average Fuel Economy standards.

The Supreme Court ruling made clear that the EPA can use the Clean Air Act as a tool to reduce harmful global warming pollution. In response, Sen. Murkowski (R-AK) and Representatives Moran (R-KS), Blackburn (R-TN), and Pomeroy (D-NC) have introduced legislation aimed at blocking the EPA’s ability to regulate greenhouse gases under the Clean Air Act. Click here to learn more about these Dirty Air Act proposals and how to voice your opposition.