US EPA

In October 2022, EPA publicly released the draft hexavalent chromium assessment for review and comment. The IRIS Toxicological Review of Hexavalent Chromium provides the scientific support and rationale for the hazard and dose-response assessment of exposure to hexavalent chromium. Following public comment, the assessment will undergo an independent external scientific peer review managed by EPA’s Science Advisory Board (SAB).

U.S. EPA. IRIS Toxicological Review of Hexavalent Chromium (External Review Draft, 2022). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-22/191, 2022.

Cr(VI) is a naturally occurring metal that has been most commonly used commercially to prevent rust and corrosion and can be found in a variety of industries, including pigment manufacturing, chrome plating, and stainless-steel production. The general population may be exposed to Cr(VI) compounds when they inhale ambient air, and ingest water or food containing Cr(VI). EPA’s previous IRIS assessment on Cr(VI) was posted in 1998. This new draft assessment updates the information based on the latest science. The draft assessment provides a comprehensive systematic review of hundreds of studies on cancer and multiple noncancer health effects of inhalation and oral exposure to Cr(VI), resulting in a state-of-the-science human health assessment.

Date	Description
01-Apr 2014	EPA released preliminary meeting materials for chromium (VI), part 1, in preparation for the June 2014 Bimonthly Public Science Meeting.
02-Jun 2014	EPA hosted a public science meeting to discuss preliminary meeting materials for chromium (VI), part 1.
03-Aug 2014	EPA released preliminary meeting materials for chromium (VI), part 2, in preparation for the October 2014 Bimonthly Public Science Meeting.
04-Oct 2014	EPA hosted a public science meeting to discuss preliminary meeting materials for chromium (VI), part 2.
05-Mar 2019	EPA released the Systematic Review Protocol for the Hexavalent Chromium IRIS Assessment (Preliminary Assessment Materials). [Federal Register Notice Mar 15, 2019]
06-Apr 2019	EPA announced that they will host a public science meeting on April 24, 2019 (by webinar) to discuss the draft document.
07-Feb 2022	EPA initiated an interagency science consultation on the draft IRIS Toxicological Review of Hexavalent Chromium.
08-Oct 2022	EPA released an update to the CrVI protocol (preliminary assessment materials), see related links for details.
09-Oct 2022	EPA released the draft IRIS Toxicological Review of Hexavalent Chromium (External Review Draft) for public comment and subsequent external peer review by EPA’s Science Advisory Board (SAB). Also, the EPA-led Interagency Science Consultation draft was released with comments. [Federal Register Notice Oct 20, 2022]

Following public comment and external peer review, the assessment will be revised prior to final posting to the IRIS Web site.

This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.

• IRIS Toxicological Review of Hexavalent Chromium (External Review Draft) (PDF)  (507 pp, 7 MB, about PDF)
• IRIS Toxicological Review of Hexavalent Chromium Supplemental Information (External Review Draft) (PDF)  (433 pp, 14 MB, about PDF)
• Charge to the External Reviewers (PDF)  (8 pp, 242 KB, about PDF)
• Appendix A: Systematic Review Protocol for the Hexavalent Chromium IRIS Assessment (Updated Oct 2022) (PDF)  (158 pp, 2 MB, about PDF)
• Review of EPA’s Draft IRIS Toxicological Review of Hexavalent Chromium (Report Number EPA-Sab-23-009)

If you have a disability and the format of any material on our web pages interferes with your ability to access the information, please reach out to us using the Contact us about IRIS form for assistance. To enable us to respond in a manner most helpful to you, please indicate the nature of the accessibility problem, the web address of the requested material, your preferred format in which you want to receive the material (electronic format (ASCII, etc.), standard print, large print, etc.), and your contact information.

• IRIS Toxicological Review of Hexavalent Chromium Part 1: Experimental Animal Studies (Preliminary Assessment Materials, 2014)
• IRIS Toxicological Review of Hexavalent Chromium Part 2: Human, Toxicokinetic, and Mechanistic Studies (Preliminary Assessment Materials, 2014)
• Updated Systematic Review Protocol for the Hexavalent Chromium IRIS Assessment (Preliminary Assessment Materials, 2019)
• IRIS Toxicological Review of Hexavalent Chromium (Interagency Science Consultation Draft, 2022)

• Primary Literature Search References Sorted By Author (Chromium VI)

• FR Notice: Oct 20, 2022

Comments on the assessment may be submitted and reviewed using the Docket ID EPA-HQ-ORD-2014-0313