The U.S. Supreme Court’s June 29th decision in Michigan v. EPA, taken together with another significant CAA opinion from last term, Utility Air Regulatory Group v. EPA, demonstrates the Court’s proclivity for subjecting agency interpretations to more rigorous scrutiny under Chevron deference. This approach could influence the Court’s analysis in other challenges to environmental regulation, including expected lawsuits regarding EPA’s “Clean Power Plan” rule, which would require reductions in carbon dioxide emissions from power plants.

Background -

The Clean Air Act (CAA) authorizes the U.S. Environmental Protection Agency (EPA) to establish standards for hazardous air pollutant emissions from stationary sources. With regard to power plants, the CAA directs EPA to conduct a study of “the hazards to public health reasonably anticipated to occur as a result of emissions” and to regulate hazardous air pollutant emissions from power plants if, based on the study, EPA determines “such regulation is appropriate and necessary.”