FUEL OXYGENATES ARE WIDELY USED in the United States. In the late 1970s and early 1980s, as lead antiknocks were removed from motor gasoline, gasoline producers used oxygenates to offset the loss in octane from the removal of lead. More recently, under the Clean Air Act, oxygenates have been used as an emission control strategy to reduce carbon monoxide (CO) in wintertime oxygenated fuel programs and as a required component in federal reformulated gasoline programs to help reduce ozone. The Clean Air Act Amendments (CAA) of 1990 require states with areas exceeding the national ambient air quality standard for carbon monoxide to implement programs requiring the sale of oxygenated gasoline containing a minimum of 2.7 % oxygen by weight during the winter months. The Clean Air Act Amendments also require the use of reformulated gasoline (RFC) in those areas of the United States with the most severe ozone pollution. Reformulated gasoline is required to contain 2.0 % oxygen by weight on average. Under the Clean Air Act Amendments and the Energy Policy Act of 1992, Congress enacted legislation requiring the use of alternative fuels and alternative fuel vehicles. Fuels containing high concentrations of ethanol or methanol, where oxygen is the primary component of the blend, qualify as alternative fuels. E85, a blend of 85 % ethanol and 15 % hydrocarbons, and M85, a blend of 85 % methanol and 15 % hydrocarbons, may be used in specially designed vehicles to comply with state and local alternative fuel programs.