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Environmental Assessment

IRIS Toxicological Review of 1,4-Dioxane (External Review Draft, 2009)

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Archived files are provided for reference purposes only. The file was current when produced, but is no longer maintained and may now be outdated. Persons with disabilities having difficulty accessing archived files may contact the NCEA Webmaster for assistance. Please visit http://epa.gov/ncea to access current information.

Report Information

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 that when finalized will appear on the Integrated Risk Information System (IRIS) database. Please refer to IRISTrack - 1,4-dioxane for the latest schedule updates.

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Eva Mclanahan
  • by phone at:   919-541-1396
  • by fax at:   919-541-0245
  • by email at:  mclanahan.eva@epa.gov


The draft Toxicological Review of 1,4-dioxane provides scientific support and rationale for the hazard and dose-response assessment pertaining to chronic exposure to 1,4-dioxane. 1,4-Dioxane is commonly used as a solvent, cleaning agent, chemical stabilizer, surface coatings, adhesive agent, and an ingredient in chemical manufacture. Human health risk concerns for 1,4-dioxane are primarily related to exposure from drinking, ground, and surface waters, although these exposure concerns have not been well characterized.

This assessment contains the derivation of a chronic reference dose and cancer oral slope factor.


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.
Jun 2009EPA announced a public listening session to be held July 6, 2009 and an external peer review workshop to be held on August 17, 2009 for the draft review report. A correction notice was posted on June 17, 2009 to confirm the listening session date as July 6, 2009.
Nov 2009EPA releases the comments from the public comment period and external review workshop.

Next Steps

Following external peer review of the report, the final assessment will be posted to the IRIS database.

Additional Information

Comments on the assessment may be submitted and reviewed using the e-Government Regulations.gov Web site. From the site, select Environmental Protection Agency and the key word EPA- HQ-ORD-2009-0210 (for the docket ID).


U.S. EPA. IRIS Toxicological Review of 1,4-Dioxane (External Review Draft, 2009). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-09/005A, 2009.


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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