Ethyl Tertiary Butyl Ether (ETBE)

Overview

In August 2013, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for ETBE to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in comments on the following:

• Draft literature search strategies
• The approach for identifying studies
• The screening process for selecting pertinent studies
• The resulting list of pertinent studies
• Preliminary evidence tables
  • The process for selecting studies to include in evidence tables
  • The quality of the studies in the evidence tables

The literature search strategy, which describes the processes for identifying scientific literature, contains the studies that EPA considered and selected to include in the evidence tables. The preliminary evidence tables and exposure-response arrays present the key study data in a standardized format. The evidence tables summarize the available critical scientific literature. The exposure-response figures provide a graphical representation of the responses at different levels of exposure for each study in the evidence table.

Background

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.

History/Chronology

Date	Description
2004	The IRIS Assessment of ethyl tertiary butyl ether was initiated in 2004.
Aug 2009	EPA released the ETBE external review draft for public review and comment.
Oct 2009	EPA held a public listening session on October 7, 2009 as announced in the September 23, 2009 Federal Register Notice.
Dec 2009	EPA 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 2010	EPA 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 2013	EPA 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.

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.

• Draft literature search and associated strategy and evidence tables for ETBE (PDF)  (58  pp, 1.4 MB, about PDF)
• All references sorted by author (ETBE) (dynamic literature link - generated by HERO, leaving the IRIS website)
• Literature selection process for ETBE - (generated by HERO, leaving the IRIS website)
• IRIS December Bimonthly Meeting -- ETBE Presentations

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Document Related Link(s)

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

Federal Register Notices

• FR Notice: Aug 9, 2013

Docket

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