On October 15, the U.S. Supreme Court agreed to hear the most significant case on the regulation of greenhouse gases since Massachusetts v. EPA in 2007. In that case, the Court ruled that the EPA was required under the Clean Air Act to determine whether greenhouse gases endanger public health or welfare, and if so, regulate emissions. EPA subsequently found that greenhouse gases do endanger “current and future generations” and established emissions regulations for both stationary (power plants) and mobile sources (new vehicles).
Those rules were challenged by several states and industry groups who argued that the EPA did not have support for its endangerment finding and that the agency did not have the authority to regulate emissions from stationary sources. Industry groups say the regulations will cost tens of billions of dollars each year. The Court of Appeals for the District of Columbia Circuit unanimously rejected the challenges.
The Supreme Court agreed to hear the appeal from the D.C. Circuit on a limited basis regarding only the issue of whether the regulation of emissions from vehicles triggered permitting requirements for stationary sources under the Clean Air Act. The decision left intact EPA endangerment finding. Oral arguments will be heard next year and a decision issued by July.