ATSDR’s Substance Priority List
US CDC - Agency for Toxic Substances and Disease Registry’s Substance Priority List
The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) section 104 (i), as amended by the Superfund Amendments and Reauthorization Act (SARA), requires Agency for Toxic Substances and Disease Registry (ATSDR) and the EPA to prepare a list, in order of priority, of substances that are most commonly found at facilities on the National Priorities List (NPL) and which are determined to pose the most significant potential threat to human health due to their known or suspected toxicity and potential for human exposure at these NPL sites. CERCLA also requires this list to be revised periodically to reflect additional information on hazardous substances. In CERCLA, it is called the priority list of hazardous substances that will be candidates for toxicological profiles.
This substance priority list is generally revised and published every two years, with an informal review and revision each year. Each substance on the list is a candidate to become the subject of a toxicological profile prepared by ATSDR. The listing algorithm prioritizes substances based on frequency of occurrence at NPL sites, toxicity, and potential for human exposure to the substances found at NPL sites. The SPL algorithm ranks the substances in this list to compute total points based on site frequency, toxicity(based on EPA Reportable Quantity), source contribution, and exposure; this list is not a list of "most toxic".