The U.S. Environmental Protection Agency (EPA) defines E15 as gasoline blended with 10.5% to 15% ethanol. In 2011, EPA approved E15 for use in light-duty conventional vehicles of model year 2001 and newer, through a Clean Air Act waiver request, based on significant testing and research funded by the U.S. Department of Energy. Stations are not required to sell E15, but some have started offering E15 due to equipment grants and better profit margins when compared with regular gasoline. E10 remains the limit for passenger vehicles older than model year 2001 and for other non-road and small engines and vehicles that use gasoline, such as lawn mowers, motorcycles, and boats. E15 is not widely available, but it is currently sold at more than 1,700 stations in 30 states. Through the U.S. Department of Agriculture's Biofuels Infrastructure Partnership, $210 million was set aside for the installation of new ethanol infrastructure, which began in 2016 and is expected to be completed in 2019.

Vehicles approved for E15 use:
  • Flexible fuel vehicles
  • Conventional vehicles of model year 2001 and newer.
Vehicles prohibited from using E15:
  • All motorcycles
  • All vehicles with heavy-duty engines, such as school buses and delivery trucks
  • All off-road vehicles, such as boats and snowmobiles
  • All engines in off-road equipment, such as chain saws and gasoline lawn mowers
  • All conventional vehicles older than model year 2001.

There are additional regulations for stations selling blends above E10. For more information, visit the Codes, Standards, and Safety page.