Alternative Fuels and Underground Storage Tanks (USTs)

Federal & State Resources / Environmental Protection Agency (EPA)

Date posted: 07/27/16

EPA underground storage tank (UST) regulations require that tank systems are compatible with the substances stored in them. The use of alternative fuels in the U.S. is growing, and federal mandates require a significant increase in biofuels production. Many retail facilities, such as gas stations, and private fueling facilities already store and dispense ethanol and biodiesel in their UST systems. Ethanol and biodiesel are commonly blended with gasoline and diesel, respectively, and are referred to by their biofuel percentage of the blend: E10, E15, or B20. These fuels are also available in some retail markets as non-blended biofuels E98 or B100. The development and availability of other alternative fuels, such as isobutanol, are growing rapidly. Each alternative fuel or alternative fuel blend has unique chemical characteristics that may be different from those of purely petroleum derived gasoline or diesel fuel. Those chemical characteristics may affect how the fuel interacts with UST system materials. Some materials in some USTs may actually not perform as intended if storing certain fuels or blends and may be incompatible with those fuels. If UST materials are not compatible with substances stored in USTs, releases to the environment can occur. Prior to storing alternative fuels, UST owners and operators should be aware of potential issues and regulations to ensure fuels are stored safely in USTs. Owners and operators must use an UST system made of or lined with materials that are compatible with the substance stored in the UST system. Compatibility is the ability of two or more substances (for example the tank or piping material and petroleum) to maintain their respective physical and chemical properties upon contact with one another. These substances need to remain compatible for the design life of the tank and under conditions likely to be encountered in the UST. Beginning on October 13, 2015 owners and operators must notify their implementing agency.