The 6-2 decision in EPA v. EME Homer City Generation, written by Justice Ruth Bader Ginsburg, stated CSAPR is a “permissible, workable and equitable interpretation of the Good Neighbor Provision” of the CAA. The Good Neighbor Provision requires state implementation plans to contain adequate provisions to prohibit emissions within a state that would contribute significantly to nonattainment in any other state with respect to any national ambient air quality standards (NAAQS).
CSPAR limits sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions limits in 28 states and was the EPA’s most recent rule designed to prevent emissions from one state from carrying downwind and affecting another. Its previous attempt, the Clean Air Interstate Rule, was also struck down by a federal appeals court but left in place.
Power companies and several states had sued to keep CSAPR from taking effect, claiming the rule exceeded EPA’s authority under the CAA. In 2012, the U.S. Court of Appeals for the D.C. Circuit struck down CSAPR in a 2-1 decision, stating EPA was attempting to require upwind states to reduce their emissions by more than authorized by the CAA act and not allowing upwind states opportunities to develop their own emission reduction requirements though a state implementation plan (SIP).
Ginsburg wrote in the court’s decision that the appeals court was correct in stating the EPA cannot require a state to reduce its output of pollution by more than necessary to achievement attainment in every downwind state, but noted “a degree of imprecision is inevitable in tackling the problem of interstate air pollution.”
“Slight changes in wind patterns or energy consumption, for example, may vary downwind air quality in ways EPA might not have anticipated,” Ginsburg wrote. “The Good Neighbor Provision requires EPA to seek downwind attainment of NAAQS notwithstanding the uncertainties. Hence, some amount of over-control, i.e., emission budgets that turn out to be more demanding than necessary, would not be surprising.”
A state that concludes it has been forced to regulate emissions beyond a point necessary may bring a more narrow challenge to the rule, according to the court.
The court also rejected claims the EPA’s formula could not factor in the cost of pollution control and stated the CAA does not require states be given a second opportunity to file a SIP after EPA has quantified the state’s interstate pollution obligation.
Justice Antonin Scalia wrote the dissent for the Supreme Court’s decision and was joined by Justice Clarence Thomas. Justice Samuel Alito was recused and did not participate in the case.
Scalia criticized the court’s opinion for allowing important federal government decisions to be made “by unelected agency officials exercising broad lawmaking authority, rather than by people’s representatives in Congress.”
“The majority’s conception of administrative discretion is so sprawling that it would allow EPA to subvert state primacy not only with respect to the interstate-pollution concerns of the Good Neighbor Provision, but with respect to the much broader concerns of the NAAQS program more generally,” Scalia wrote in his dissent.
EPA Administrator Gina McCarthy supported the court’s decision on Twitter, calling it “a big win for nation’s public health & proud day for the agency.”
The case will now return to the U.S. Court of Appeals for the D.C. Circuit.