American Trucking Ass'n v. EPA

The court holds that the U.S. Environmental Protection Agency's (EPA's) construction of the Clean Air Act (CAA) in promulgating the revised national ambient air quality standards (NAAQS) for ozone and particulate matter (PM) effects an unconstitutional delegation of legislative power and remands the case for EPA to articulate an intelligible principle for setting such standards. The court first holds that in promulgating the standards, EPA construed CAA §§108 and 109 so loosely as to render the NAAQS unconstitutional delegations of legislative power. Although the factors EPA uses in determining the degree of public health concern associated with different levels of ozone and PM are reasonable, EPA appears to have articulated no intelligible principle to channel its application of these factors; nor is one apparent from the statute. The nondelegation principle requires such a principle. On remand, EPA must develop a construction of the CAA that satisfies this constitutional requirement.

The court next holds that in setting NAAQS for ozone and PM, EPA did not err when it failed to consider the costs of implementing those standards or the environmental consequences resulting from the financial impact of those standards on the federal Abandoned Mine Reclamation Act. Moreover, the court holds that EPA did not violate the National Environmental Policy Act, the Unfunded Mandates Reform Act, or the Regulatory Flexibility Act in setting the ozone and PM NAAQS.

The court then holds that the 1990 amendments to the CAA did not alter EPA's power to revise the ozone NAAQS and to designate areas as nonattainment under a revised standard. The court, however, holds that EPA is precluded from enforcing a revised primary ozone NAAQS other than in accordance with the classification, attainment dates, and control measures set out in the 1990 amendments. EPA's authority under CAA §172 to set classifications and attainment dates is limited by the 1990 amendments, which under Subpart 2 of CAA Part D, specifically provides the classifications and attainment dates for any area designated nonattainment under a revised primary ozone NAAQS. Further, the court holds that EPA is precluded from requiring any steps toward compliance with a revised secondary ozone NAAQS prior to an area's attainment of the primary ozone standard. In areas that meet the primary ozone standard, however, Subpart 2 erects no bar to EPA's requiring compliance with a revised secondary ozone NAAQS as expeditiously as practicable. The court also holds that EPA must consider the positive identifiable health effects of a pollutant's presence in the ambient air in formulating air quality criteria under CAA §108 and NAAQS under CAA §109. On remand, EPA must determine whether ozone has a beneficent effect, and if so, must assess ozone's net adverse health effect by whatever criteria it adopts.

The court next holds that the record contains sufficient evidence to justify EPA's decision to regulate coarse particulate pollution. The court, however, holds that EPA's retention of PM with a diameter of 10 micrometers or less (PM[10]) as the indicator for coarse PM simultaneously with its establishment of the new fine particle indicator as PM having a diameter of 2.5 micrometers or less (PM[2.5]) is unsupported by the record and, thus, arbitrary and capricious. The court, therefore, vacates PM[10] standard. The court then holds that EPA is not regulating PM[2.5] for the first time and, thus, does not need to list it separately as a new pollutant under CAA §108. The court also holds that in establishing the fine PM standard, EPA was not required to explain the biological mechanism through which particulate pollution causes adverse health effects. Last, the court holds that Congress did not intend the secondary PM NAAQS to eliminate all adverse visibility effects and, therefore, that EPA acted within the scope of its authority in deciding to rely on the regional haze program to mitigate some of the adverse visibility effects caused by PM[2.5].

A judge dissenting in part would hold that the record demonstrates that in setting the NAAQS for ozone and PM, EPA's construction of CAA §109 was not an unconstitutional delegation of legislative power.

Counsel for Petitioners
Edward W. Warren
Hunton & Williams
1900 K St. NW, Washington DC 20006
(202) 955-1500

Counsel for Respondent
Mary F. Edgar
Environment and Natural Resources Division
U.S. Department of Justice, Washington DC 20530
(202) 514-2000

Before Williams, Ginsburg, and Tatel, JJ.