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Fact Sheet
Integrated Risk Information System (IRIS)

IRIS is a toxicology data file on the National Library of Medicine's (NLM) Toxicology Data Network (TOXNET®). It contains data in support of human health risk assessment, including hazard identification and dose-response assessments. It is compiled by the U.S. Environmental Protection Agency (EPA) and contains over 500 chemical records with descriptive and quantitative information related to human cancer and non-cancer health effects that may result from exposure to substances in the environment. IRIS data, focusing on hazard identification and dose-response assessment, is reviewed by work groups of EPA scientists and represents EPA consensus. Among the key data provided in IRIS are EPA carcinogen classifications, unit risks, slope factors, oral reference doses, and inhalation reference concentrations. More information can be found at the EPA's IRIS website.

Web Access/Searching

IRIS is accessible, free of charge, via TOXNET at:

Users can search by chemical or other name, chemical name fragment, Chemical Abstracts Service Registry Number (RN), and/or subject terms. Search results can easily be viewed, printed or downloaded. Search results are displayed in relevancy ranked order. Users may select to display exact term matches, complete records, or any combination of data from the following broad groupings:

  • Chronic Health Hazard Assessment for Noncarcinogenic Effects
  • Carcinogenicity Assessment for Lifetime Exposure
  • Oral RfD References
  • Inhalation RfC References
  • Carcinogenicity Assessment References

Users can conduct their IRIS search strategy against other databases: Hazardous Substances Data Bank®, Chemical Carcinogenesis Research Information System, GENE-TOX, TOXLINE®, ChemIDplus®, and ITER®.

Further Information

For further information about IRIS or TOXNET, contact:

IRIS Representative
Specialized Information Services
National Library of Medicine
Two Democracy Plaza, Suite 510
6707 Democracy Boulevard, MSC 5467
Bethesda, MD 20892-5467
Fax: (301) 480-3537
Telephone: (301) 496-1131

For comments on IRIS content, contact:

IRIS Hotline at the EPA

For general information on NLM services, contact:

National Library of Medicine
Customer Service
8600 Rockville Pike
Bethesda, MD 20894
Telephone: 1-888-FINDNLM (1-888-346-3656)
NLM Customer Service Form at Contact NLM

A complete list of NLM Fact Sheets is available at:
(alphabetical list)
(subject list):

Or write to:

Office of Communications and Public Liaison
National Library of Medicine
8600 Rockville Pike
Bethesda, Maryland 20894

Phone: (301) 496-6308
Fax: (301) 496-4450