The EPA last week approved higher amounts of ethanol blended into gasoline to be sold at gas stations in the U.S. during summer months, but many automakers warn against using fuel with more than 10 percent ethanol content in their vehicles.
The EPA said that it will allow fuel with 15 percent ethanol content—marketed as E15 at pumps—to be sold between June 1 through the end of September. Previously, the standard was 10 percent, or E10. Ethanol-free gas is legal but unusual in most urban areas.
Some areas specifically ban E15 use.
"EPA is not pre-empting state and local rules on the matter," the EPA told Green Car Reports.
Ethanol for fuel is obtained from corn and soybean. The EPA's move is considered a boon to farmers, but it has drawn the ire of oil industry and clean-air advocates, however. The fuel has been linked to increased air pollution in urban areas, especially during hot summer months. When ethanol is mixed with gasoline at higher rates, the fuel evaporates quicker, which leads to smog.
Ethanol is approved by the EPA for use in all vehicles from the 2001 model year and newer, but not older cars. Automakers recommend verifying if cars are approved for E15 use by looking through owner's manuals. Green Car Reports listed BMW, Mini, Mazda, Mitsubishi, and Subaru as brands that do not approve of E15 use in many their vehicles, although many models made by other automakers are not E15-compatible, either.