On October 29, 1999, a nine-judge panel of the Court of Appeals for the District of Columbia Circuit denied, in part, EPA's motion for rehearing on the court's prior decision regarding the Clean Air Act's public health-based standard for determining pollutant levels.
Significantly, in denying the rehearing, the court let stand its prior decision that, with respect to the factors the agency uses to determine the degree of public health concern associated with different levels of a pollutant, EPA "appears to have articulated no 'intelligible principle' to channel its application of these factors, nor is one apparent from the statute." American Trucking Ass'ns v. USEPA, 175 F.3d 1027, 1034 (D.C. Cir., 1999).
The court's ruling questions whether the Clean Air Act's Section 109 language regarding promulgating national ambient air quality standards and EPA's existing interpretation of that language involves an unconstitutional delegation of power. The court's most recent decision lets stand the court's prior decision vacating portions of EPA's revised national ambient air quality standard for ozone and particulate matter, and remanding the matter to EPA. EPA has indicated that it will appeal the court's decision to the Supreme Court.
