Ethyl Tertiary Butyl Ether (ETBE)

CASRN 637-92-3

  • Status: Ethyl Tertiary Butyl Ether (ETBE) is in step 5 at this time.

IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (Public Comment Draft)

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In September 2016, the U.S. Environmental Protection Agency's (USEPA) released the draft Integrated Risk Information System (IRIS) Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE). Consistent with the 2013 IRIS Enhancements, draft IRIS assessments are released prior to external peer review for a 60-day public comment period and discussed at an upcoming public science meeting. Accordingly, the toxicological review, supplementary information, and other materials pertaining to this draft assessment are posted on this site.


U.S. EPA. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (Public Comment Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-16/184, 2016.


J. Andre Weaver,  Ph:  703-347-0194,  Email:

Kathleen Newhouse,  Ph:  703-347-8641,  Email:

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ETBE is used as a fuel additive for gasoline to increase octane rating and has been used to meet air pollution reduction goals in the U.S. under the Clean Air Act. The use of ether oxygenates such as ETBE in reformulated gasoline in the U.S. was effectively eliminated in 2006; however, use and production of these oxygenates has continued in Europe and Asia for the purpose of increasing octane rating in gasoline. ETBE may be used as a substitute to replace the volume and oxygenate properties of methyl tertiary butyl ether, an oxygenate widely used in the U.S. prior to 2006. The main source of exposure to ETBE in the U.S. is from exposure to contaminated groundwater due to leaking underground storage tanks.


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 held a public listening session to discuss the draft assessment for ETBE as announced in the September 23, 2009 Federal Register Notice.
Jan 2010EPA held an external peer review meeting to discuss the draft report on January 26, 2010, as announced 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.
Aug 2013EPA released preliminary assessment materials (e.g., literature searches and associated search strategies, evidence tables, and exposure response arrays) of ETBE for public discussion at the December 2013 IRIS Bimonthly Public Meeting.
Dec 2013EPA convened public science meeting to discuss preliminary assessment materials.
Sep 2014EPA submitted the draft assessments of ETBE for Interagency Science Consultation.
Sep 2016EPA announced the availability of the draft assessment of ETBE for public comment and discussion and released the interagency science consultation draft, EPA response to select comments, and comments from reviewers. This was announced in a September 1, 2016 Federal Register Notice.
Oct 2016EPA convenes an IRIS Public Science Meeting to discuss the IRIS assessment of ETBE (Public Comment Draft).


Following public comment and external peer review, the assessment will be revised taking into consideration peer review and public comments. The assessment will then undergo a final EPA internal review and a review by other federal agencies and the Executive Office of the President. Once final, the assessment will be posted to the IRIS database.

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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.

Federal Register Notices


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

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