The Agency for Toxic Substances and Disease Registry (ATSDR) studies the health effects of hazardous substances in general and at specific locations. As indicated by its title, the Agency maintains a registry of people exposed to toxic chemicals. Along with the Environmental Protection Agency (EPA), ATSDR prepares and updates profiles of toxic substances. In addition, ATSDR assesses the potential dangers posed to human health by exposure to hazardous substances at Superfund sites. The Agency will also perform health assessments when petitioned by a community. Though ATSDR's early health assessments have been criticized, the Agency's later assessments and other products are considered more useful.

ATSDR was created in 1980 by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), also known as the Superfund, as part of the U.S. Department of Health and Human Services. As originally...