Natural Resources Defense Council, Inc. v. Environmental Protection Agency

In 1985 the United States Environmental Protection Agency (EPA) (defendant) promulgated a rule establishing that the recommended maximum contaminant level (RMCL) for fluoride in drinking water was 4 milligrams per liter. The EPA passed the rule pursuant to its authority under the Safe Drinking Water Act, which authorized the EPA to set the RMCLs of different contaminants, including fluoride, by considering any known or anticipated adverse health effects caused by the contaminant. In response to the EPA’s promulgation of the rule, the Natural Resources Defense Council, Inc. (the defense council) and the South Carolina Department of Health and Environmental Control (the department) each filed an action against the EPA in federal district court on the ground that the EPA had acted arbitrarily and capriciously in determining the RMCL for fluoride. The defense council claimed that the EPA should have promulgated a lower RMCL because (1) the amount provided did not unequivocally protect individuals against crippling skeletal fluorosis, particularly for those individuals who drank more than average amounts of water, (2) the amount failed to target dental fluorosis, because the EPA had defined adverse health effects as anything amounting to functional rather than cosmetic impairments, and (3) the EPA did not consider other risks associated with fluoride. However, the EPA questioned the accuracy of the data provided and explained the reason it felt the data was inaccurate. The defense council introduced evidence that dental fluorosis could lead to psychological issues, including issues with self-confidence due to a change in one’s physical appearance, and argued that such issues constituted adverse health effects. The department argued that the EPA should not have promulgated any rule establishing an RMCL for fluoride, because the data on RMCLs was inconclusive. The district court returned a verdict in favor of the EPA. The matter was appealed to the United States Court of Appeals for the District of Columbia Circuit.