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 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. 

This CERCLA priority list is revised and published on a 2-year basis, with a yearly informal 

review and revision. Each substance on the CERCLA Priority List of Hazardous Substances is a 

candidate to become the subject of a toxicological profile prepared by ATSDR and subsequently 

a candidate for the identification of priority data needs. This priority list is based on an 

algorithm that utilizes the following three components: 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, which contains information from 

ATSDR's public health assessments and health consultations. 

Thus, it is possible for substances with low toxicity but high NPL frequency of occurrence and 

exposure to be on this priority list. The objective of this priority list is to rank substances across

all NPL hazardous waste sites to provide guidance in selecting which substances will be the 

subject of toxicological profiles 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 document also contains an appendix 

showing the breakdown of the total scores for each substance on the priority list. To view this 

support document, click here. 

It should be noted that this priority list is not a list of "most toxic" substances, but

rather a prioritization of substances based on a combination of their frequency, 

toxicity, and potential for human 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 voiced by community groups 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 

ATSDR - CERCLA Priority List of Hazardous Substances Page 1 of 2

http://www.atsdr.cdc.gov/cercla/ 12/3/2009
 

Page last reviewed: Sept. 1, 2009 

Page last updated: Sept. 1, 2009 

Content source: Centers for Disease Control and Prevention 

Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, 

Atlanta, GA 30341 

Contact CDC: 800-232-4636 / TTY: 888-232-6348 

Contact Information 

Further information can be obtained by contacting the ATSDR Information Center at: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology and Environmental Medicine 

1600 Clifton Road NE, Mailstop F-32 

Atlanta, GA 30333 

Phone: 1-800-CDC-INFO • 888-232-6348 (TTY) 

Email: cdcinfo@cdc.gov

You may also access the previous 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 Hazardous Substances for 1999 

z CERCLA Priority List of Hazardous Substances for 1997

ATSDR - CERCLA Priority List of Hazardous Substances Page 2 of 2

http://www.atsdr.cdc.gov/cercla/ 12/3/2009