Winston’s Environmental Law Update

EPA’s Mercury and Air Toxics Standards (MATS), which regulates emissions of hazardous air pollutants (HAPs) from coal- and oil-fired electric utility steam generating units (EGUs), was promulgated in 2012. Underpinning the rule was EPA’s determination under § 112(n)(1)(A) of the Clean Air Act that it is appropriate and necessary to regulate HAP emissions from coal- and oil-fired EGUs. In making its appropriate and necessary determination, EPA did not consider costs, which spurred legal challenges.

Following the Supreme Court’s 2015 decision in Michigan v. EPA requiring EPA to consider costs before regulating utilities under Section 112 of the Clean Air Act, litigation regarding the several aspects of the Mercury and Air Toxics Standards (MATS) continues in the U.S. Court of Appeals for the D.C. Circuit.

On June 13, 2016, the Supreme Court of the United States denied an appeal from states and industry in Michigan v. EPA regarding the Mercury & Air Toxics Standards. 

On March 17, 2016, EPA finalized its long-awaited technical corrections to the Mercury and Air Toxics Standards (MATS) which were proposed in December 2014.

On March 18, 2016, a group of 20 states led by Michigan appealed the U.S. Court of Appeals for the D.C. Circuit’s decision to remand the Mercury and Air Toxics Standards to EPA without vacatur.

On March 3, 2016, Chief Justice Roberts denied, without comment, a request from a coalition of 20 states to stay implementation of the Mercury and Air Toxics Standards (MATS) which the D.C. Circuit remanded to EPA on December 15, 2015. 

Today, the Supreme Court of the United States held that EPA unreasonably interpreted the Clean Air Act to not require it to consider costs when determining whether it is appropriate and necessary to regulate hazardous air pollutant emissions from power plants under Section 112 of the Clean Air Act.