American Trucking and other private companies, with the states of West Virginia, Michigan, and Ohio, responded to the EPA’s administrative revision of the NAAQS for particulate matter and ozone. The respondents held the position that the terms, “adequate margin”, and “requisite”, set forward by congress left room for economic considerations when setting standards under the CAA. The court, however, held an entirely different position. Justice Scalia proclaimed that the respondents must prove a clear textual commitment to the EPA considering costs during revisions, which does not exist. Furthermore, the court believes it improbable that congress would leave such ambiguities given the clear language and intention of the statute. The result was a resounding affirmation of the EPA’s standards.

Using health-based standards, the Clean Air Act is enforced by the EPA, which is charged with the “attainment and maintenance of which are requisite to protect the public health with an adequate margin of safety”. If the plaintiffs had won, the results would have been disastrous for the EPA as well as societies health. Such a precedent would undermine the CAA by making health-based standards subject to economic influence, essentially setting the stage for individual states to usurp the federal preemption of the CAA via private industry. Subsequently, the ruling of the court upheld the standard that societal health concerns hold higher value than the fiscal gains of private firms, which was the initial spirit of the CAA.