ELR Citation: 42 ELR 20141
No(s). 09-1322 et al (D.C. Cir. Jun 26, 2012)

The D.C. Circuit upheld four EPA rulemakings governing greenhouse gases. EPA issued the rules following the U.S. Supreme Court's decision in Massachusetts v. EPA, 549 U.S. 497 (2007), in which the Court clarified that greenhouse gases meet the definition of an air pollutant under the CAA. Petitioners, various states and industry groups, challenged these rules, arguing that they are based on improper constructions of the CAA and are otherwise arbitrary and capricious. Specifically, they challenged: (1) EPA's endangerment finding, in which it determined that greenhouse gases may "reasonably be anticipated to endanger public health or welfare;" (2) the Agency's tailpipe rule, which set greenhouse gas emission standards for cars and light trucks; (3) EPA's determination that the CAA requires major stationary sources of greenhouse gases to obtain construction and operating permits; and (4) the timing and tailoring rules, in which EPA determined that only the largest stationary sources would initially be subject to permitting requirements. The court ruled that the endangerment finding and tailpipe rule are neither arbitrary nor capricious. EPA's interpretation of the governing CAA provisions is unambiguously correct. As for the timing and tailoring rules, the petitioners lack standing.