Legend has it that during Prohibition, bootleggers used to put their brew in the gas tanks of their getaway cars.⁷ Today, almost half of all gasoline sold in the U.S. contains ethanol.⁸ Most of that gasoline is what’s known as “E10” – a mixture that is 90 percent or more unleaded gasoline and ten percent or less ethanol. The ethanol in E10 raises both the oxygen and the octane content of gasoline, allowing it to burn more efficiently and produce fewer toxic emissions. Most of the 240 million passenger cars and trucks on the road today can safely use E10 without violating the terms of their manufacturers’ warranties.⁹ Six million of those cars can safely use E85, a blend that is 85 percent ethanol and 15 percent unleaded gasoline.