The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) mandates that the Agency for Toxic Substances and Disease Registry (ATSDR) shall assess whether adequate information on health effects is available for the priority hazardous substances. Where such information is not available or under development, ATSDR shall, in cooperation with the National Toxicology Program, initiate a program of research to determine these health effects. The Act further directs that where feasible, ATSDR shall develop methods to determine the health effects of substances in combination with other substances with which they are commonly found. The Food Quality Protection Act (FQPA) of 1996 requires that factors to be considered in establishing, modifying, or revoking tolerances for pesticide chemical residues shall include the available information concerning the cumulative effects of substances that have a common mechanism of toxicity, and combined exposure levels to the substance and other related substances. The FQPA requires that the Administrator of the Environmental Protection Agency consult with the Secretary of the Department of Health and Human Services (which includes ATSDR) in implementing some of the provisions of the act.

To carry out these legislative mandates, ATSDR’s Division of Toxicology (DT) has developed a chemical mixtures program. As part of the mixtures program, ATSDR developed a guidance manual that outlines the latest methods for mixtures assessment. In addition, a series of documents called Interaction Profiles are being developed for certain priority mixtures that are of special concern to ATSDR. The purpose of the Interaction Profile is to evaluate data on the toxicology of the 'whole' priority mixture (if available) and on the joint toxic action of the chemcials in the mixture in order to recommend approaches for the exposure-based assessment of the potential hazard to public health.

1. DRAFTS: The interaction profiles are first produced as drafts. ATSDR announces in the Federal Register the release of these draft profiles for a 90-day public comment period. For more information about the public comment process, see below.
2. FINALS: After the 90-day comment period, ATSDR considers incorporating all comments into the final profile.

Although key studies for each of the 'Draft' Interaction Profiles were considered during the profile development oprocess, ATSDR now solicits any additional studies and comments, which will be evaluated for possible addition to the 'Final' Profiles.

The Public Comment period for some began on or about June 1, 2002 and continued through September 2, 2002.

The Public Comment period for others began on or about August 30, 2002 and continues through November 30, 2002.

Check the individual interaction profile Web pages listed below for the exact dates that apply to that specific profile.

Written comments and other data submitted in response to these 'Draft' Interaction Profiles and the Guidance Assessment should bear the docket control number ATSDR-182.

Send one copy of all comments and three copies of all supporting documents by the end of the comment period to

Division of Toxicology (DT),
Agency for Toxic Substances and Disease Registry
1600 Clifton Road, Mailstop F-32
Atlanta, GA 30333

• Arsenic, Cadmium, Chromium, Lead
• Benzene, Toluene, Ethylbenzene, Xyelene
• Lead, Manganese, Zinc, Copper
• Persistent chemicals found in breast milk
• Persistent chemicals found in fish
• 1,1,1-TCE, 1,1-DCE, TCE, PERC
• Cesium, Cobalt, Polychlorinated Biphenyls, Strontium, and Trichloroethylene
• Arsenic, Hydrazines, Jet Fuels, Strontium-90, and Trichloroethylene
• Cyanide, Fluoride, Nitrate, and Uranium

• Guidance Manual for the Assessment of the Joint Toxic Action of Chemical Mixtures