IRIS Toxicological Review of Tert-Butyl Alcohol (TBA) (External Review Draft, 2017)

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The IRIS Toxicological Review of tert-Butyl Alcohol (tert-Butanol or tBA) 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 tBA assessment and release a final report of their review. Information regarding the peer review can be found on the SAB website.

tert-Butyl Alcohol (tBA) is used as a solvent; as a denaturant for ethanol and several other alcohols; in the manufacture of flotation agents, fruit essences, and perfumes; as an octane booster in gasoline; as a dehydrating agent; and as a chemical intermediate in the manufacture of methyl methacrylate. tBA's production for industrial uses may result in its direct release to the environment through various waste streams. tBA is also a likely degradation product of methyl tert-butyl ether (MTBE). Probable routes of human exposure to tBA include inhalation, ingestion, and skin or eye contact.


EPA is conducting an Integrated Risk Information System (IRIS) health assessment for tert-butanol (TBA). The outcome of this project is a Toxicological Review for TBA 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 Tert-Butyl Alcohol (TBA) (External Review Draft, 2017). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-17/015, 2017.


Date Description
01-Aug 2013EPA released preliminary assessment materials (draft literature searches and associated search strategies, evidence tables and exposure response arrays) for discussion at an IRIS Public Science Meeting.
02-Dec 2013EPA discussed tert-butanol at the December 2013 IRIS public science meeting.
03-Sep 2014EPA sent an interagency science consultation draft for review and comment.
04-May 2016EPA released the public comment draft for public review and comment.
05-Jun 2016EPA convened a public science meeting June 29-30, 2016 to discuss the public comment draft.
06-Jun 2017EPA released the external review draft and charge to reviewers prior to the public peer review meeting.[SAB FR Notice Jun 16, 2017]
07-Jul 2017EPA's Science Advisory Board (SAB) hosted a public teleconference to discuss the draft assessment.
08-Aug 2017EPA's SAB hosted a 2-day public meeting on August 15-17, 2017, to discuss the draft assessment.
09-Feb 2019EPA's SAB released a final report of their review of the draft IRIS assessment (see downloads).