U.S. EPA authority to use cumulative risk assessments in environmental decision-making

Abstract

Conventionally, in its decision-making, the U.S. EPA has evaluated the effects and risks associated with a single pollutant in a single exposure medium. In reality, people are exposed to mixtures of pollutants or to the same pollutant through a variety of media, including the air, water, and food. It is now more recognized than before that environmental exposure to pollutants occurs via multiple exposure routes and pathways, including inhalation, ingestion, and dermal absorption. Moreover, chemical, biologic, radiologic, physical, and psychologic stressors are all acknowledged as affecting human health. Although many EPA offices attempt to consider cumulative risk assessment and cumulative effects in various ways, there is no Agency-wide policy for considering these risks and the effects of exposure to these risks when making environmental decisions. This article examines how U.S. courts might assess EPA's general authority and discretion to use cumulative risk assessment as the basis for developing data in support of environmental decision-making, and how courts might assess the validity of a cumulative risk assessment methodology itself.

Keywords: U.S. Environmental Protection Agency; cumulative effects; cumulative risk; environmental justice; statutory authority.

Figure 1

Chevron test—Two-part framework for resolving agency interpretations of statutes.

Figure 2

Under the APA, the court will conduct a “searching and careful” review and ask whether the agency made a decision that was not “arbitrary and capricious”. (Note that the steps are not necessarily sequential.)