This specification prescribes performance and regulatory requirements as well as the corresponding test methods for natural gasoline to be used as a hydrocarbon blendstock in ethanol fuel blends for flexible-fuel automotive spark-ignition engines. In the United States, these blends are known commercially as Ethanol Flex Fuel.

This specification also covers natural gasoline intended for use as a denaturant in denatured fuel ethanol for blending with gasoline to be used as automotive spark-ignition engine fuel. The products shall conform to specified requirements for workmanship, distillation, corrosion (for silver), sulfur, vapor pressure, solvent-washed gum content, and benzene.