## CERCLA Priority List of Hazardous Substances

What is the CERCLA List? The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) section 104 (i), as amended by the Superfund Amendments and Reauthorization Act (SARA), requires ATSDR and the EP A to prepare a list, in order of prio rity, of substances that are most commonly found at facilities on the National Priorities List (NPL) and which are determined to pose the most significant potent ial 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 b e revised periodically to re flect additional in formation on hazard ous substances. This CERCLA priority li st is revised and published on a 2-ye ar basis, with a yearly informal review and revision. Each substance on the CERCLA Priority List of Hazardous Substances is a candidate to become the su bject of a toxicological p rofile p re p ared b y

ATSDR and subse q uentl y a candidate for the identification of priority data needs. This priority list is based on an algorithm that utilizes the following three com ponents: frequency of occurrence at NPL sites, toxicity, and potential for human exposure to the substances found at NPL sites. This algorithm utilizes data from ATSDR's HazDat database, whic h contains information from A

TSDR's p ublic health assessments an d health consultations.

Thus, it is possible for substa nces with low toxicity but high NPL frequency of occurrence and exposure to be on this priority li st. The objective of this priority list is to rank substances across all NPL hazardous waste sites to provide guidance in selectin g which substances will be the subject of toxicological prof iles prepared by ATSDR. There is a Support Document to the CERCLA Priority List of Hazardous Substances that describes in detail how the list is developed. This support docu ment also contains an appendix showing the breakdown of the total scores for each substance on the priori ty list. To view this support document, click here

. It should be noted that this priority list is not a list of "m ost toxic" substances, but rather a prioritization of substances based on a combin ation of their frequency, toxicity, and potential for hu man exposure at NPL sites.



### Related information The ATSDR Division of Toxicology has prepared several sets of publications that provide answers to many health concerns that are vo iced by community grou ps and give general information on various properties of each of these substances. Those publications are listed and may be accessed online at the following links:

z ATSDR ToxFAQsTM Sheets

z ATSDR Public Health Statements

z ATSDR Toxicological Profiles Page 1 of 2 ATSDR - CERCLA Priority Li st of Hazardous Substances

12/3/2009 htt p ://www.atsdr.cdc. g ov/cercla /Page last reviewed: Sept. 1, 2009 Page last updated: Sept. 1, 2009 Content source: Centers for Disease Control and Prevention

A gency for Toxic Substances and Dise ase Registry, 4770 Buford Hwy NE, A

tlanta, GA 30341 Contact CDC: 800-232-46 36 / TTY: 888-232-6348 

### Contact Information Further information can be obtained by cont acting the ATSDR Info rmation Center at: Ag enc y

for Toxic Substances and Disease Registry Division of Toxicology an d Environmental Medicine 1600 Clifton Road NE, Mailstop F-32 A

tlanta, GA 30333 Phone: 1-800-CDC-INFO • 888-232-6348 (TTY) Email: cdcinfo@cdc.gov Y

ou ma y

also access the p revious lists online:

z CERCLA Priority List of Hazardous Substances for 2007

z CERCLA Priority List of Hazardous Substances for 2005

z CERCLA Priority List of Hazardous Substances for 2003

z CERCLA Priority List of Hazardous Substances for 2001

z CERCLA Priority List of Haza rdous Substances for 1999

z CERCLA Priorit y

List o f Hazardous Substances for 1 997 Page 2 of 2 ATSDR - CERCLA Priority Li st of Hazardous Substances

12/3/2009 htt p ://www.atsdr.cdc. g ov/cercla /