On August 18, EPA filed a brief in the U.S. Court of Appeals for the DC Circuit arguing that the agency adhered strictly to Section 202(a)(1) of the Clean Air Act’s guidelines for science-based decision-making in determining that GHG emissions from vehicles endanger public health and the environment. EPA argued its determination was “a protective, science-based judgment (not a fact-finding exercise) that is focused solely on potential threats to public health and welfare posed by air pollution.”