Chemical Manufacturers Association v. NRDC

The EPA created a “fundamentally different factors” (FDF) variance to let indirect dischargers of toxic pollutants seek individualized relief from otherwise-applicable effluent limitations, addressing the practical impossibility of accounting for every atypical discharger when setting categorical standards under strict statutory timetables. The Natural Resources Defense Council (plaintiff) argued this variance rule violated § 301(l) of the Clean Water Act, which barred the EPA from “modifying any requirements” for toxic pollutants; the court of appeals agreed and struck down the rule, and the Supreme Court granted certiorari.