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Environmental Assessment

IRIS Toxicological Review of n-Butanol (External Review Draft, 2011)


EPA has released the Toxicological Review of n-Butanol (External Review Draft) for public review and comment. EPA has reopened the public comment period, announced in the November 16, 2011, Federal Register Notice until December 7, 2011.

Report Information

EPA is conducting a peer review of the scientific basis supporting the human health hazard and dose-response assessment of n-butanol that will appear in the Integrated Risk Information System (IRIS) database. Please refer to IRISTrack - n-Butanol for the latest schedule updates.

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Ambuja Bale
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  • by email at:  bale.ambuja@epa.gov


The draft Toxicological Review of n-Butanol provides scientific support and rationale for the hazard and dose-response assessment pertaining to chronic exposure to n-butanol. n-Butanol is widely used as an organic solvent and is an intermediate in the manufacture of other organic chemicals such as acetates, acrylates and glycol ethers. n-Butanol is also a natural component of many foods and formed during the fermentation of carbohydrates.


Mar 1987A RfD was posted for n-butanol to the IRIS Database.
Mar 1991The cancer assessment for n-butanol was posted to the IRIS Database.
Jun 2011EPA initiated the interagency science consultation on the draft Toxicological Review of n-Butanol.
Sep 2011EPA released the external review draft for public review and comment. EPA concurrently released the interagency science consultation draft toxicological review and charge, and interagency comments with EPA's response.

Next Steps

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 Regulations.gov Web site. From the site, select “Environmental Protection Agency” and the keyword “EPA-HQ-ORD-2011-0671" (for the docket ID) to comment on this report.


U.S. EPA. IRIS Toxicological Review of n-Butanol (External Review Draft, 2011). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-11/081A, 2011.


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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