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An Overview of the IRIS Web site

Welcome to the IRIS Web site & Database! This overview provides you with some information to help you navigate IRIS and understand the subject matter. This website conveys information on assessments posted to the database by the EPA’s IRIS Program as well as assessments under development.

For substances with assessments posted to the database, the IRIS website presents health effects information using three different formats:

• Quick View
• IRIS Summary
• Toxicological Review

For assessments under development, the IRIS website provides a tracking tool to help you monitor the status of upcoming substance assessments:

• IRISTrack

The A to Z List of IRIS Substances provides links to each of these health assessment formats and IRISTrack.

Quick View

The IRIS QuickView presents a snapshot of the information available in the IRIS Summary and is intended to be a quick reference guide to key carcinogenic and noncarcinogenic data for each substance contained in the IRIS database. See either the IRIS Summary or the Toxicological Review for a more complete description and greater context.

The format of the QuickView parallels that of the IRIS Summary.

IRIS Summary

The IRIS Summary provides IRIS toxicity values and brief summaries of the information supporting those values, including the critical effect, the principal and supporting studies, uncertainty factors, and key references.  The IRIS Summary also includes a revision history and list of synonyms for a given substance.

For more thorough analysis and documentation, a link to the pdf of the Toxicological Review is available on the IRIS Summary page for substances posted to the database since 1997.

Toxicological Review

The Toxicological Review provides scientific support and rationale for the hazard and dose-response risk information in IRIS human health assessments. All Toxicological Reviews are subjected to a full and open independent expert peer review process, including opportunity for public review and comment. Included in the document is information on chemical and physical properties, toxicokinetics, available pharmacokinetic modeling, hazard identification, mode-of-action and dose-response, as well as reference doses (RfD), reference concentrations (RfC), cancer slope factors and unit risks, and cancer descriptors that can be utilized in risk assessments. Toxicological Reviews are available for assessments posted to the IRIS database since 1997.

IRISTrack

The IRIS substance assessment tracking system (IRISTrack) is a compilation of status reports for EPA's IRIS assessments currently in progress. The status report shows the anticipated dates of major milestones, detailing where the substance assessment is in its development.

IRISTrack Milestones:

• Step 1 — Draft Development: For each draft assessment, a chemical manager is assigned to work with a team comprised of toxicologists, epidemiologists, and statisticians in reviewing and analyzing the available scientific literature. EPA's risk assessment guidelines form the basis for the analysis. The team develops a draft Toxicological Review. Scientific studies must be peer reviewed and published prior to the commencement of Agency Review (Step 2) in order to be included in the Toxicological Review.
• Step 2 — Agency Review: The purpose of Agency Review is to provide expert internal peer review of the draft assessment and help identify scientific issues that should be raised during external peer review. The draft assessment is reviewed by a standing group of senior health scientists representing EPA's Offices and Regions and by selected EPA scientists with expertise relevant to the substance under review.
• Step 3 — Interagency Science Consultation: EPA submits the draft Toxicological Review and draft external peer review charge questions to other federal agencies and the Executive Office of the White House for a science consultation. A meeting is held to discuss scientific issues of interest to other agencies. All draft materials, interagency comments, and a summary of major comments and EPA's responses are made publicly available on the IRIS Web site when the draft assessment is posted for public comment and external review.
• Steps 4 and 5 — Public Comment and External Peer Review: Each IRIS assessment undergoes a rigorous, open, and independent external peer review. Assessments are made available for public comment prior to external peer review. The public is invited to attend the external peer review meeting and may address the panel at the meeting. Additionally, public comments are made available to the external peer review panel prior to the meeting. Following the meeting, a report of the peer review comments is made publicly available on the IRIS Web site. EPA revises the assessment according to the recommendations of the peer review panel. In addition, all public comments are taken into consideration. At this point, no new studies are incorporated into assessments unless recommended by a peer review panel.
• Step 6 — Final Agency Review/Interagency Science Discussion: Following the external peer review, EPA simultaneously submits the revised draft Toxicological Review for final Agency review and for final interagency science discussion to other federal agencies and the Executive Office of the White House for a review of how EPA has responded to the external peer review and public comments. A second interagency meeting is held. The interagency draft Toxicological Review, interagency comments, and a summary of major comments and EPA's responses are made publicly available on the IRIS Web site when the final assessment is posted.
• Step 7 — Final Assessment: The final assessment is posted to the IRIS Web site. The final IRIS Summary is available to the public along with the supporting Toxicological Review.

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