On August 21, 2012, in a highly unusual disagreement with a rulemaking action by a Federal agency, the D.C. Circuit Court of Appeals sent the Environmental Protection Agency’s (“EPA”) Cross-State Air Pollution, or Transport, Rule, governing sulfur dioxide (“SO2”) and oxides of nitrogen (“NOx”) emissions, back to the agency with firm instructions to try again, and, next time, do a better job. What makes this decision somewhat unusual is that cross-state rules had previously been implemented by EPA for PM2.5 and ozone, and upheld by the D.C. Circuit, see, e.g., Michigan v. EPA, 213 F.3d 663 (D.C. Cir. 2000) and North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008).
In its decision in EME Homer City Generating, L.P., et al. v. EPA, et al., Case No. 11-1302, the D.C. Circuit took strong issue with EPA’s attempt to meet its responsibility under Clean Air Act § 110(a)(2)(D)(i)(I), 49 U.S.C. § 7410(a)(2)(D). That section, the “good neighbor” provision, requires, in pertinent part, that, after EPA sets National Ambient Air Quality Standards (“NAAQS”), 42 U.S.C. § 7409, and designates areas within each state which exceed the NAAQS, 42 U.S.C. § 7407(d), or “nonattainment” areas, states must develop a state implementation plan (“SIP”), 42 U.S.C. § 7410, which includes provisions prohibiting any emissions source or activity “which will – contribute significantly to nonattainment in, or interfere with maintenance by, any other state with respect to any such national primary or secondary ambient air quality standard.” The D.C. Circuit found major legal flaws in EPA’s Transport Rule.