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. The final rule, which has not yet been published in the Federal Register, makes a number of key changes to the MATS requirements. For example, EPA has finalized revisions to the emissions averaging equations and changed the requirements concerning use of clean fuels during startup. EPA also removed the rule’s affirmative defense for malfunctions in light of the D.C. Circuit’s April 2014 decision in NRDC v. EPA. The final rule will become effective once published in the Federal Register.

Meanwhile, EPA sent its final supplemental MATS cost analysis to the White House Office of Management & Budget (OMB) for review on March 22, 2016. The Agency was required to perform the cost analysis after the Supreme Court’s decision in Michigan v. EPA, which held that EPA erred by failing to consider the costs of regulating hazardous air pollutant emissions from the utility industry in its “appropriate and necessary” determination under the Clean Air Act. OMB is expected to complete its review of the cost analysis in May 2016, after which it will be published in the Federal Register.