The Renewable Fuel Standard—which brought Americans mandated ethanol-blended fuels—would disappear under a bill introduced by U.S. Reps. John Shimkus (R-Ill.) and Bill Flores (R-Texas).

A draft of the bill reveals a shift toward octane mandates in place of biofuel requirements.

The draft bill—called the 21st Century Transportation Fuels Act—also includes a provision requiring car makers to build vehicles capable of using 95-octane E20 fuel (20 percent ethanol by volume) for the 2023 model year and beyond.

The draft bill also would hold the renewable volume obligations at 15 million gallons of ethanol a year from 2020 through 2022 and allow the sale of E15 fuel year-round.