Environmental Defense Fund v. EPA

The Toxic Substances Control Act (TSCA) contained provisions defining the scope of regulation for a class of chemicals called polychlorinated biphenyls (PCBs). If PCBs were used in ways that did not result in any leakage, these uses were deemed totally enclosed uses, a designation that exempted the uses from regulation under the TSCA. By contrast, uses of PCBs that resulted in leakage were referred to as non-totally enclosed uses, and these uses were not exempt from regulation under the TSCA. Pursuant to the TSCA, the Environmental Protection Agency (EPA) (defendant) enacted a rule banning non-totally enclosed uses that contained concentrations of PCBs greater than 50 parts per million (ppm). However, although the EPA found that any exposure to PCBs might have adverse health and environmental effects, it was not aware of the amount of PCBs left unregulated by the 50 ppm cutoff. The EPA also enacted a rule identifying certain commercial uses of PCBs as totally enclosed uses, such that these uses were not subject to the 50 ppm cutoff. Yet, because the EPA did not have any procedures for inspecting leaks, it had no idea which PCB uses were in fact totally enclosed. The Environmental Defense Fund (plaintiff) brought suit, contending that the EPA’s rules were invalid. The court of appeals had original jurisdiction to hear the case.