US Supreme Court considers EPA greenhouse gas emissions regulations

May the U.S. Environmental Protection Agency regulate greenhouse gas emissions from power plants and industry under the Clean Air Act?

The Supreme Court of the United States heard oral argument on this issue yesterday, in the case Utility Air Regulatory Group v. Environmental Protection Agency, Docket No. 12-1146.  How the court rules on the case will shape federal regulation of carbon dioxide and other greenhouse gas emissions in the nation.

The case arises from EPA's decision in 2010 to regulate greenhouse gas emissions from power plants and industrial facilities.  That decision stemmed from a 2007 Supreme Court ruling, Massachusetts v. EPA, requiring EPA to regulate greenhouse gas emissions from motor vehicles under Title II of the Clean Air Act.  Since 1980, EPA has held that once it regulates one type of air pollution (e.g. greenhouse gases from motor vehicles), it may (or must) broaden its regulations to cover all such emissions (e.g. greenhouse gases from all sources).  Applying this precedent in 2010, EPA found that regulating motor vehicle greenhouse gas emission standards under Title II of the Clean Air Act also compelled EPA to regulate greenhouse gas emissions under the Clean Air Act's Title I "prevention of significant deterioration" or PSD program, as well as under its Title V stationary-source permitting program.

Building on its Title II regulation of greenhouse gas emissions from cars and trucks, EPA then promulgated its Title I and Title V regulatory programs for stationary sources.  These rules regulated stationary sources emitting 75,000 tons of carbon dioxide or more per year, but triggered challenges from several states, over 70 non-governmental advocacy groups, and business interests.  While challengers raised a host of objections, one of the key substantive issues raised was whether EPA may truly regulate carbon dioxide as a "pollutant."  Challengers also mounted attacks rooted in law, questioning whether EPA's 2010 decision to regulate motor vehicle greenhouse gas emissions could legally trigger permitting requirements for stationary sources.

After the U.S. Court of Appeals for the D.C. Circuit upheld EPA's rules, challengers appealed that decision to the Supreme Court.  While the Court declined to address most of the issues challengers raised, it decided to entertain argument on one point: "Whether EPA permissibly determined that its regulation of greenhouse gas emissions from new motor vehicles triggered permitting requirements under the Clean Air Act for stationary sources that emit greenhouse gases."

The Court's official docket for Utility Air Regulatory Group v. Environmental Protection Agency can be found here, and unofficial copies of many of the pleadings can be found on SCOTUSBlog.  While the Court has not indicated when it will rule on the case, energy and other industries are watching closely for the ultimate outcome.