D.C. Circuit Upholds EPA Greenhouse Gas Regulations

On June 26, 2012, the U.S. Court of Appeals for the D.C. Circuit upheld a suite of U.S. Environmental Protection Agency (EPA) actions related to the regulation of greenhouse gas (GHG) emissions under the federal Clean Air Act (CAA).¹ In particular, the court upheld the EPA's "Endangerment Finding" and "Tailpipe Rule," and dismissed petitions for review of the "Timing Rule" and "Tailoring Rule." With the D.C. Circuit's decision, all challenged aspects of the EPA's GHG regulations will remain in effect, dealing a heavy blow to opponents of the agency's policy on climate change.

Regulatory Background

The consolidated appeals before the D.C. Circuit had been brought by large group of industrial actors and states who were dissatisfied with the agency's GHG-related rulemakings under the CAA subsequent to the U.S. Supreme Court's landmark decision in Massachusetts v. EPA, 549 U.S. 497 (2007), which established GHGs as "pollutants" under the CAA and required the EPA to