ELR Citation: 45 ELR 20072
No(s). 98-1322 et al (D.C. Cir. Apr 10, 2015)

The D.C. Circuit, in light of the U.S. Supreme Court's decision in Utility Air Regulatory Group v. EPA, No. 12-1146, 44 ELR 20132 (2014), amended a prior decision in which it upheld four EPA rulemakings governing greenhouse gases (GHGs). The four rules are: (1) EPA's endangerment finding, in which it determined that GHGs may "reasonably be anticipated to endanger public health or welfare"; (2) the Agency's tailpipe rule, which set GHG emission standards for cars and light trucks; (3) EPA's determination that the CAA requires major stationary sources of GHGs 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. In Utility Air Regulatory Group, the Supreme Court held that EPA's regulation of GHG emissions from new motor vehicles did not automatically trigger the CAA's permitting requirements for stationary sources that emit GHGs. The Court vacated portions of the Agency's "tailoring" rule mandating PSD permits for stationary sources that emit more than 100,000 tons of GHGs per year. The D.C. Circuit, therefore, ordered that the four regulations at issue here be vacated only to the extent they: (1) require a stationary source to obtain a PSD permit if GHGs are the only pollutant that the source emits or has the potential to emit above the applicable major source thresholds, or for which there is a significant emissions increase from a modification; (2) require a stationary source to obtain a title V permit solely because the source emits or has the potential to emit GHGs above the applicable major source thresholds; and (3) require EPA to consider further phasing-in the requirements identified in (1) and (2) above, at lower GHG emission thresholds. The underlying petitions for review by various states and industry groups were otherwise vacated in their entirety.