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) (Interagency Science Consultation Draft)

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In September 2016, EPA released the draft IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) for public comment and discussion. The draft assessment was reviewed internally by EPA and by other federal agencies and White House Offices before public release. Consistent with the May 2009 IRIS assessment development process, all written comments on IRIS assessments submitted by other federal agencies and White House Offices are made publicly available. Accordingly, interagency comments and the interagency science consultation materials provided to other agencies, including interagency review drafts of the IRIS Toxicological Review of Ethyl Tertiary Butyl Ether are posted on this site.


U.S. EPA. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (Interagency Science Consultation Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-14/373, 2014.


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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 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 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 United States prior to 2006. The main source of exposure to ETBE in 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.

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