On February 25, 2016, EPA published a final rule in the Federal Register that amended the regulatory definition of Volatile Organic Compounds (VOC) under the Clean Air Act to exclude t-butyl acetate (aka tertiary butyl acetate) for all regulatory purposes. The regulatory definition of VOC already excludes t-butyl acetate for purposes of VOC emission limitations and VOC content requirements on the basis that it makes a negligible contribution to ozone formation. However, the current definition still includes t-butyl acetate as a VOC for purposes of recordkeeping, emission reporting, and photochemical dispersion modeling that applied to VOCs in general. The final rule is effective on April 25, 2016. 

EPA noted that its final rule and determination to remove t-butyl acetate from all regulatory requirements relating to VOCs does not indicate that EPA has reached final conclusions about all aspects of the health effects posed by the use of the chemical. EPA noted it is currently awaiting completion of the IRIS assessment associated with the potential risk of exposure to t-butyl acetate and its potential toxicity.