July 2015

In a 5-4 decision in Michigan v EPA, the U.S. Supreme Court remanded to the lower court an EPA rule designed to reduce mercury and other air toxic emissions from coal-fired power plants.  The Supreme Court ruled that EPA erred by not including costs when it first considered regulating coal-fired power plants under the Mercury and Air Toxic standards.  While EPA did not consider costs when it first contemplated regulating coal-fired power plants under the mercury and air toxics standard, EPA did include extensive cost-benefit analysis in the development of the rule.  EPA estimated that the rule would cost $9.6 billion annually to comply with and would yield $4-$6 million annually in benefits from mercury reduction and $36 to $90 billion annually in other benefits – primarily ozone and particulate matter pollution reductions.

The short-term practical implications of the Supreme Court decision are limited.  The rule will remain in effect until the lower court – in this case D.C. District Court of Appeals – can reconsider the rule.

The ATS submitted an amicus curiae or friend of the court brief supporting implementation of the EPA Mercury Air Toxics rule.  The ATS brief provided background information to the court about the adverse health effects of mercury and other air toxic exposures.