CASRN 123-91-1

IRIS Toxicological Review of 1,4-Dioxane (with Inhalation Update) (External Review Draft)

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EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of 1,4-Dioxane (with inhalation update) that when finalized will appear on the Integrated Risk Information System (IRIS) database.


U.S. EPA. IRIS Toxicological Review of 1,4-Dioxane (with Inhalation Update) (External Review Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/003A, 2011.


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1,4-Dioxane is commonly used as a solvent, cleaning agent, chemical stabilizer, surface coating, adhesive agent, and an ingredient in chemical manufacture. The IRIS Program completed the assessment for oral exposure to 1,4-dioxane on August 11, 2010 and noted that new inhalation studies would be evaluated separately. Additional information regarding 1,4-dioxane toxicity resulting from exposure via inhalation has now been incorporated into the 2010 assessment without changing the oral toxicity conclusions of the previous assessment.


Date Description
Aug 1988EPA released the assessment for 1,4-Dioxane.
Oct 2003The IRIS reassessment of 1,4-dioxane was initiated.
May 2009EPA released an external review draft for public review and comment.
Sep 2009EPA hosted an interagency science discussion on the review of the draft Toxicological Review of 1,4-dioxane.
Aug 2010EPA released the final assessment of 1,4-dioxane on the IRIS Web site.
May 2011EPA initiated the interagency science consultation on the draft Toxicological Review of 1,4-Dioxane.
Sep 2011EPA released the external review draft (with inhalation update) for public review and comment. EPA concurrently released the interagency science consultation draft toxicological review and charge, and interagency comments with EPA's response.
Sep 2011EPA extended the close of the public comment period to November 15, 2011. [Federal Register Notice Sep16, 2011]
Feb 2012EPA announced that an independent panel of experts will meet in Morrisville, NC on March 19, 2012 to discuss the draft report. [Federal Register Notice Feb 13, 2012]
May 2012EPA released the comments from the public comment period and external review workshop.


Following external peer review and public comment, the assessment will be revised taking into consideration the comments received. It will then undergo a final internal review by EPA and other federal agencies and White House offices. After completing the review it will be posted to the IRIS database.

Additional Information

Comments on the assessment may be submitted and reviewed using the e-Government Web site. From the site, select “Environmental Protection Agency” and the keyword “EPA-HQ-ORD-2011-0390" (for the docket ID) to comment on this report.

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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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