Chlorine Chemistry Council v. Ep

206 F.3d 1286 (2000)

Facts

The Safe Drinking Water Act directs D to set standards for the regulation of covered drinking water contaminants. D sets a 'maximum contaminant level goal' ('MCLG'), defined as 'the level at which no known or anticipated adverse effects on the health of persons occur and which allows an adequate margin of safety.' After having set it, EPA is to promulgate an enforceable standard, known as a maximum contaminant level ('MCL'), which takes practical considerations into account while remaining 'as close to the [MCLG] as is feasible.' In March 1998, D concluded that chloroform, a drinking water contaminant, exhibits a 'nonlinear mode of carcinogenic action.' Exposures to chloroform below some threshold level pose no risk of cancer. In repromulgating the MCLG, it retained the existing standard of zero, which was based on the previously held assumption that there was no safe threshold. Ps, a trade association comprised of chlorine and chlorine product manufacturers, appealed arguing that D violated its statutory mandate to use the 'best available' evidence when implementing the provisions of the Safe Drinking Water Act.