In a brief order, the U.S. Court of Appeals for the D.C. Circuit has allowed the EPA to continue implementing its Mercury and Air Toxics Standards (MATS) for fossil-fuel power plants while the Agency works on finalizing a proposed determination that consideration of cost does not alter EPA’s previous determination that it is appropriate to proceed with such implementation.
![]() |
In a brief order, the U.S. Court of Appeals for the D.C. Circuit has allowed the EPA to continue implementing its Mercury and Air Toxics Standards (MATS) for fossil-fuel power plants while the Agency works on finalizing a proposed determination that consideration of cost does not alter EPA’s previous determination that it is appropriate to proceed with such implementation.
The D.C. Circuit’s order follows a June 2015 majority ruling by the U.S. Supreme Court, which found that the EPA erred when it determined that compliance costs were irrelevant to the requirements of the 2012 final MATS. That ruling overturned an earlier opinion in which the D.C. Circuit found that EPA’s position that it was necessary and appropriate to require that power plants control emissions of air toxics did not require cost considerations.
The EPA won its point in the circuit court by noting, among other things, that when Congress wrote Clean Air Act (CAA) Section 112, it included no specific instructions to consider costs in setting the standards. Section 112 requires that the Agency establish maximum achievable control technology (MACT) requirements to reduce emissions of hazardous air pollutants emitted by sources in specific industrial sectors.