The scope of this SAE Information Report is the liquid fuel containment system for gasoline or flexible fuels (up to 85% methanol in gasoline), along with their associated vapors, as designed for use on passenger cars and light trucks. For purposes of this document, fuel containment addresses the fuel tank and components that are directly attached to the fuel tank. These components may include the filler neck, tank, fill vent tube, fuel cap, pump-sender, and rollover control valve closure seals, insofar as they act as closure or containment mechanisms. Emphasis will be on fuel containment and the required system closures. Furthermore, emphasis will be placed on design recommendations as they relate to performance. Mounting and shielding of the "system" components are only included to the extent they affect the containment aspects.