Today, June 29, 2015, the U.S. Supreme Court issued a 5-to-4 decision reversing the D.C. Circuit’s decision to uphold EPA’s rule establishing mercury and air toxics standards (MATS) for electric generating units. The case is Michigan, et al. v. EPA, et al., No. 14-46.

The Court granted review on a single issue: "Whether the Environmental Protection Agency unreasonably refused to consider costs in determining whether it is appropriate to regulate hazardous air pollutants emitted by electric utilities."

Writing for the majority, Justice Scalia held that EPA “strayed far beyond” the “bounds of reasonable interpretation” when the Agency interpreted the Clean Air Act to mean that it “could ignore costs when deciding to regulate power plants.” The Court remanded the case to the D.C. Circuit for further proceedings consistent with the Court’s opinion.

Click here to view the decision.