Ethyl tertiary butyl ether (ETBE)

CASRN 637-92-3

  • Status: Ethyl tertiary butyl ether (ETBE) is in step 4 at this time.

IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (External Review Draft, 2009)

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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 ethyl tertiary butyl ether (ETBE) that when finalized will appear on the Integrated Risk Information System (IRIS) database.


U.S. EPA. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (External Review Draft, 2009). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-08/019A, 2009.


Scott C. Wesselkamper,  Ph:  513-569-7256,  Email:

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The draft Toxicological Review of Ethyl Tertiary Butyl Ether provides scientific support and rationale for the hazard and dose-response assessment pertaining to chronic exposure to ethyl tertiary butyl ether. Ethyl tertiary butyl ether is used as a fuel additive for gasoline to increase octane rating and has been used to meet air pollution reduction goals under the Clean Air Act. The use of ether oxygenates such as ethyl tertiary butyl ether in reformulated gasoline in the United States was effectively eliminated in 2006; however, use and production of these oxygenates has continued for the purpose of increasing octane rating in gasoline. Ethyl tertiary butyl ether has been used extensively in Europe and may be used as a substitute to replace the volume and oxygenate properties of methyl tertiary butyl ether, an oxygenate widely used in the United States prior to 2006. Plastic plumbing pipe, particularly silane cross-linked polyethylene (PEX), represents an additional potential source of ethyl tertiary butyl ether in drinking water.


Date Description
2004The IRIS Assessment of ethyl tertiary butyl ether was initiated in 2004.
Aug 2009EPA released the ETBE external review draft for public review and comment.
Oct 2009EPA announces a public listening session to be held on October 7, 2009 as explained in the September 23, 2009 Federal Register Notice.
Dec 2009EPA announces the details of an external peer review workshop to be held on January 26, 2010 in a December 22, 2009 Federal Register Notice.
Mar 2010EPA released the comments from the public comment period and external review workshop. Development of this draft was then halted pending the completion of several new studies that were identified during the peer review.


This draft has been archived.

Additional Information

Note: On August 31, 2009, EPA posted an updated version of the report that includes an update on pages 40-45 of 9 missing lines due to a figure placement. Please contact the email or phone listed under contacts for more specific information.

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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.


Comments on the assessment may be submitted and reviewed using the Docket ID EPA-HQ-ORD-2009-0229

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