CASRN 18540-29-9

IRIS Toxicological Review of Hexavalent Chromium (2010 External Review Draft)

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Hexavalent chromium has been used historically in the chrome plating of metals, as an ingredient in dyes and pigments, in the leather tanning process, and as a wood preservative. It is often released into the environment following the disposal of chromium-containing materials or as a by-product of the processes that use this metal. EPA had determined some time ago that hexavalent chromium can cause cancer in humans when they are exposed to it by breathing, but until recently, little information was available regarding its potential to cause cancer in humans when ingested.

In September 2010, EPA released a draft IRIS assessment for hexavalent chromium, for the oral route of exposure only, for peer review and public comment. An independent expert peer review panel met in May 2011 to review the draft assessment. In their final report, the peer review panel urged EPA to consider the results of research that would soon be completed and peer-reviewed that could provide relevant scientific information that may inform the findings of the assessment.

EPA takes seriously its commitment to rigorous independent expert peer review. Based on the advice of the peer review panel, EPA will review original primary research related to the health effects of hexavalent chromium that has been published since the release of the draft assessment for external peer review and will incorporate the findings as appropriate into its hexavalent chromium assessment.


U.S. EPA. IRIS Toxicological Review of Hexavalent Chromium (2010 External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-10/004A, 2010.

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The draft Toxicological Review of Hexavalent Chromium provides scientific support and rationale for the hazard and dose-response assessment pertaining to chronic exposure to hexavalent chromium via ingestion.

Chromium is a naturally occurring element in the earth's crust. The three main forms of chromium found in the environment are chromium (0), chromium (III), and chromium (VI), also known as hexavalent chromium. Chromium is widely used in manufacturing processes, and it can be found in many consumer products such as wood treated with copper dichromate, leather tanned with chromic sulfate, and stainless steel cookware. Chromium is released to the environment from natural and anthropogenic sources, with the largest releases occurring from industrial sources. The general population may be exposed to chromium by inhaling ambient air, and ingesting food and drinking water containing chromium. Dermal exposure to chromium can occur from skin contact with certain consumer products or soils that contain chromium.


Date Description
01-Sep 1998The oral RfD for hexavalent chromium was posted to the IRIS database. The inhalation RfC for hexavalent chromium and the carcinogenicity assessment for hexavalent chromium were also posted to the IRIS database.
03-May 2010EPA initiated an interagency science consultation to review the draft toxicological review and charge to external peer reviewers.
04-Sep 2010EPA released the external review draft for public review and comment and the interagency science consultation review draft with comments. EPA also announced a public listening session to be held on November 18, 2010. [Federal Register Sep 30, 2010]
05-Nov 2010EPA extended the public comment period an additional 30-days. [Federal Register Nov 10, 2010]
06-Apr 2011EPA has announced that the peer review panel workshop on the draft assessment for Hexavalent Chromium will be held on May 12, 2011 in Arlington, VA. [Federal Register Apr 12, 2011]
07-Jul 2011EPA releases the comments from the public comment period and external review workshop.


This draft has been archived.

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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.

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