Summary

On April 2, 2007, the U.S.Supreme Court rendered an important envronmental decision. In Massachusetts v. EPA, the Court held that greenhouse gases (GHGs), widely viewed as contributing to climate change, constitute air pollutants as that phrase is used in the Clean Air Act (CAA). As a result, said the Court, the U.S. Environmental Protection Agency (EPA) had improperly denied a petition seeking CAA regulation of GHGs from new motor vehicles by saying the agency lacked authority over such emissions.

This report presents a chronology of major federal agency actions, mainly by EPA, in the wake of Massachusetts v. EPA. Most of the listed actions trace directly or indirectly back to the decision— EPA’s “endangerment finding” for GHG emissions from new motor vehicles, the agency’s standards for GHG emissions from new motor vehicles, its interpretation of the phrase “pollutants subject to regulation” (the CAA trigger for requiring BACT for such pollutants in “prevention of significant deterioration” areas), guidance for determining BACT for GHG emissions, the “tailoring rule” (limiting the stationary sources that initially will have to install BACT and obtain CAA Title V permits based on GHG emissions), and recently announced settlements of litigation seeking to compel EPA to promulgate new source performance standards (NSPSs) for GHG emissions from electric generating units (power plants) and petroleum refineries. A few agency actions were included solely because of their relevance to climate change and their post- Massachusetts occurrence—for example, EPA’s responses to California’s request for a waiver of CAA preemption allowing that state to set its own limits for GHG emissions from new motor vehicles, and EPA’s monitoring rule for GHG emissions.

More analytical treatment of the government actions in this report may be found in Congressional Research Report (CRS Report) RL32764, Climate Change Litigation: A Survey, by Robert Meltz; CRS Report R40984, Legal Consequences of EPA’s Endangerment Finding for New Motor Vehicle Greenhouse Gas Emissions, by Robert Meltz; CRS Report RS22665, The Supreme Court’s Climate Change Decision: Massachusetts v. EPA, by Robert Meltz; CRS Report R40585, Climate Change: Potential Regulation of Stationary Greenhouse Gas Sources Under the Clean Air Act, by Larry Parker and James E. McCarthy; and CRS Report R40506, Cars, Trucks, and Climate: EPA Regulation of Greenhouse Gases from Mobile Sources, by James E. McCarthy.

Note

This summary was taken from the Congressional Research Service Report R41103 by Robert Meltz