This litigation by the NAM and other business groups against the EPA went all the way to the U.S. Supreme Court in 2001 (see Whitman v. American Trucking Associations, Inc.)
. The Court remanded it to the D.C. Circuit for further proceedings regarding the validity of EPA's standard for ozone and particulate matter. On 3/26/02, the D.C. Circuit found that the EPA's 1997 NAAQS rules for PM2.5 and ozone are neither arbitrary nor capricious. The Court denied petitions for review except to the extent the Supreme Court’s 2001 decision and the D.C .Circuit’s 1999 decisions require further action by the EPA.The D.C. Circuit began by pointing out that its earlier decisions addressed only whether the Clean Air Act (or the EPA’s reading of the CAA) adequately limits the EPA’s discretion. However, the 3/26 decision involves whether the EPA reasonably exercised its discretion under the CAA. The Court found that the agency was not arbitrary and capricious in promulgating either rule.
With respect to PM2.5, the Court said that the EPA need not “identify perfectly safe levels of pollutants” and need not “definitively identify pollutant levels below which risks to public health are negligible.” Importantly, the Court also rejected environmental groups’ challenges to the PM2.5 standard as insufficiently stringent.
On ozone, the Court found that the EPA had a basis for its conclusion that the existing one-hour standard was inadequate. Based on the rulemaking docket, the Court concluded that the EPA’s choice of the 0.08 parts per million level was not arbitrary and capricious. Earlier holdings that the 8-hour ozone implementation policy is unlawful and that the EPA must consider evidence of ground-level ozone’s beneficial effects are left undisturbed by this ruling.