On March 29, 2018, EPA published a notice in the Federal Register seeking public comment on any aspect of the use of isobutanol in gasoline. Butamax Advanced Biofuels, LLC (“Butamax”), a manufacturer of isobutanol, has submitted an application pursuant to the regulations titled “Registration of Fuels and Fuel Additives” for the registration of isobutanol as a gasoline additive at up to 16 volume percent. Butamax has submitted information that would likely satisfy the applicable registration requirements. The Clean Air Act requires the EPA to register a fuel or fuel additive once all the applicable registration requirements have been met by the manufacturer. Due to the potential for the widespread introduction of isobutanol into commerce, EPA is taking steps to make the public aware of the likelihood of this registration. They are seeking public comment regarding any issues they should take into consideration for this registration and any supplemental actions they should consider under the Clean Air Act to further protect public health and welfare. Comments must be received on or before April 28, 2018. Docket ref: EPA-HQ-OAR-2018-0131. EPA contact: James W. Caldwell, Compliance Division, Office of Transportation and Air Quality, (202) 343-9303; Email address: caldwell.jim@epa.gov.