DC Circuit Remands PM2.5 Implementation Rules To EPA

On January 4, 2013, the U.S. Court of Appeals for the District of Columbia Circuit held in Natural Resources Defense Council v. EPA, No. 08-1250, that the U.S. Environmental Protection Agency (EPA) had improperly promulgated two rules implementing standards for fine particulate matter (PM2.5) under the Clean Air Act (CAA). Because of this ruling, the EPA will have to reissue the challenged rules under different provisions of the CAA, which is likely to result in the imposition of more stringent requirements on the regulated community. In addition, the court discussed when statements made in the preamble to a rulemaking can be considered “final actions” that are subject to appeal.

Background