Supreme Court Strikes Down EPA's Mercury And Air Toxics Standard

Delivering a sharp blow to President Obama's efforts to regulate coal plants, the U.S. Supreme Court invalidated the Environmental Protection Agency's (EPA's) 2012 Mercury and Air Toxics Standards (MATS) rule, finding that the agency improperly failed to consider compliance costs in determining that the regulation of coal- and oil-fired power plants was “appropriate and necessary” under the Section 112 of the Clean Air Act, 42 U.S.C. § 7412(n)(1)(A).

In a 5-4 opinion by Justice Scalia, the Supreme Court held in Michigan v. EPA, No. 14-46 (June 29, 2015), that the EPA's decision not to consider costs when determining that regulation of power plants under the hazardous-air-pollutants program wasappropriate and necessary was an unreasonable...