Special Topics in Environmental Management

Compatibility Demonstration is Mandatory for USTs Storing Biofuels

Facilities that are covered the UST regulations at 40 CFR part 280 and that also store biofuels have additional compliance concerns when compared to storing pure petroleum-based fuels. Storage of both diesel blends above 20-percent biodiesel and ethanol and ethanol blends above 10-percent ethanol require that UST operators demonstrate biofuels compatibility with their storage tanks and system components.

There are several events that trigger the demonstration of compatibility including:

  • When a new UST is brought online,
  • When existing USTs are converted to biofuels storage, and
  • When repairs are made to any of the following UST system components, all of which must be                compatible with biofuels as described above:
    • Tank or internal tank lining
    • Piping
    • Line detector
    • Flexible connectors
    • Drop tube
    • Spill and overfill prevention equipment
    • Submersible turbine pump and components
    • Sealants (including pipe dope and thread sealant), fittings, gaskets, o-rings, bushings, couplings,               and boots,
    • Containment sumps (including submersible turbine pumps and under dispenser containment)
    • Release detection floats, sensors and probes,
    • Fill and riser caps, and
    • Product shear valve.

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According to the EPA, demonstrating compatibility can be achieved in three ways:

1) By using UST system components that are certified or listed by a nationally recognized, independent testing laboratory (e.g., Underwriters Laboratories) for use with the fuel to be stored.

2) By using components approved by the manufacturer to be compatible with the fuel to be stored. The Environmental Protection Agency (EPA) accepts manufacturer approvals that:

  • Are in writing
  • Indicate an affirmative state,
  • Specify the range of biofuel blends that component is compatible with,
  • Are from the equipment manufacturer, not an installer/distributer or other entity.

3) By using another method determined by the agency with jurisdiction that is sufficient to protect human health and the environment.


Join us for an in-depth webinar on February 5. Our speaker, an experienced EHS professional who has helped companies understand UST regulations and develop comprehensive, compliant UST programs, will provide a clear path forward for preparing to comply with the potential UST regulations.


Regarding ethanol fuels specifically, the EPA noted in its June 2011 Guidance on Compatibility of UST Systems with Ethanol Blends Greater than 10 Percent and Biodiesel Blends Greater than 20 Percent, that the American Petroleum Institute’s (API’s) second edition of API 1626, an industry code of practice for meeting ethanol blend compatibility, may be used to demonstrate compatibility for ethanol fuel blends above 10 percent.

Also in that Guidance, the EPA stressed that UST operators that cannot demonstrate compatibility between the UST systems and intended biofuels may not store such biofuels in that system. In  addition, many states have more stringent UST requirements and there may also be additional local, state and federal regulations that apply, such as those related to health and safety and fire codes.

The EPA offers a wide variety of compatibility-related information on its web site at http://www.epa.gov/oust/altfuels/ethcompat.htm,  including links to industry associations, state programs and other agencies involved in different aspects of UST/biofuels compatibility research, technology and industry standards.

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