US EPA

The IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) was released for external peer review in June 2017. EPA’s Science Advisory Board’s (SAB) Chemical Assessment Advisory Committee (CAAC) will conduct a peer review of the scientific basis supporting the ETBE assessment and release a final report of their review. Information regarding the peer review can be found on the SAB website.

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.

EPA is conducting an Integrated Risk Information System (IRIS) health assessment for Ethyl Tertiary Butyl Ether (ETBE). The outcome of this project is a Toxicological Review for ETBE that will be entered into the IRIS database for use in decision making and risk assessment by EPA program and regional offices, as well as state, federal, and international agencies.

Following external peer review, the assessment will be revised. 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.

U.S. EPA. IRIS Toxicological Review of Ethyl Tertiary Butyl Ether (ETBE) (External Review Draft, 2017). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-17/016, 2017.