EPA will propose federal restrictions for perchlorate allowed in drinking water by Oct. 31, 2018, according to a legal settlement reached last week. More than five years ago, EPA announced its intention to regulate the chemical in drinking water because of public health concern, but the agency has since missed deadlines under the Safe Drinking Water Act. Perchlorate is an oxidizer used in rocket fuel, explosives, and fireworks. The chemical has been found in public drinking water systems that serve some 16 million people in the U.S., according to the Natural Resources Defense Council (NRDC), an environmental group that sued EPA for inaction. EPA has identified perchlorate as a contaminant in drinking water, and the National Research Council concluded that perchlorate contamination in drinking water could affect thyroid function. According to the settlement with NRDC, the agency will set a maximum contaminant level in drinking water and an enforceable national water regulation for perchlorate no later than Dec. 19, 2019. The regulations are likely to create cleanup liability obligations for the military, NASA, the Department of Energy, and defense contractors with operations that released perchlorate.