EPA has promulgated various requirements for motor vehicle fuel under the Clean Air Act, which apply to both gasoline and diesel fuel. However, most of these requirements apply only during part of the year or to only certain geographic areas. If the fuels waiver criteria have been met, EPA may grant a waiver to allow use of a fuel that normally is not allowed in a particular time period or geographic area.
For example, the volatility of gasoline is controlled each year during the high ozone season of June 1st through September 15th. In addition, the gasoline used in certain urban areas is subject to volatility standards that are more stringent than in surrounding rural areas. A fuels waiver may allow use of higher volatility gasoline from rural areas to address a fuels supply shortage in an urban area. Similarly, a waiver of the summer volatility requirements could allow winter grade gasoline to be used during the summer high ozone season. However, gasoline volatility standards are necessary to control the emissions of volatile organic compounds (VOC), which contributes to ozone pollution. Fuels waivers that allow use of gasoline with higher volatility may result in increased VOC emissions.
For this reason, the Clean Air Act provides strict criteria for when fuels waivers may be granted, and requires that waivers be limited as much as possible in terms of their geographic scope and duration.