On October 15, 2013, the Supreme Court granted certiorari in a case reviewing EPA’s greenhouse gas rule for stationary sources. Following the Supreme Court’s 2007 decision in Massachusetts v. EPA, 549 U.S. 497 (2007), where the court found that greenhouse gases could be an air pollutant under the Clean Air Act, EPA promulgated a greenhouse gas rule for motor vehicles. EPA believed that regulating greenhouse gas emissions from motor vehicles also required EPA to regulate greenhouse gas emissions from stationary sources, such as power plants and factories. EPA then promulgated rules incorporating greenhouse gas limits into the Prevention of Significant Deterioration and Title V air permitting schemes.

Several states and industry groups challenged EPA’s new rules in the Court of Appeals for the District of Columbia Circuit. That court upheld the rules, prompting the Supreme Court to grant certiorari on the narrow issue of “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 high court denied other petitions for certiorari seeking review of other greenhouse gas issues, including EPA’s finding that greenhouse gases pose a danger.