&EPA
Office of Underground Storage Tanks, Washington, D.C. 20460
www.epa.gov/oust
June 2011
Guidance On Compatibility Of UST Systems
With Ethanol Blends Greater Than 10 Percent
And Biodiesel Blends Greater Than 20 Percent
This guidance discusses how owners and operators of underground
storage tanks (USTs) regulated under 40 CFR part 280 can demonstrate Background
compliance with EPA's compatibility requirement (40 CFR 280.32) when
storing gasoline containing greater than 10 percent ethanol or diesel
containing greater than 20 percent biodiesel. In 1988, EPA promulgated
the compatibility requirement (and all other UST requirements) under the
authority of Subtitle I of the Solid Waste Disposal Act, as amended.
This guidance applies in Indian country and in states that do not have
state program approval (SPA). Because SPA states must have a
compatibility requirement that is similar to the Federal compatibility
requirement, SPA states may find this guidance relevant and useful to
them as well.
The discussion in this document is intended solely as guidance. The
statutory provisions and EPA regulations described in this document
contain legally binding requirements. This document is not a regulation
itself, nor does it change or substitute for those provisions and
regulations. Thus, it does not impose legally binding requirements on
EPA, states, or the regulated community.
In March 2009, EPA received a Clean Air Act (CAA) waiver application to
increase the allowable ethanol content of a gasoline-ethanol blended fuel
from 10 percent ethanol to 15 percent ethanol.1 In October 2010 and
January 2011, EPA conditionally granted partial waivers, allowing gasoline-
ethanol blends that contain greater than 10 percent ethanol up to 15
percent ethanol (E15) to be introduced into commerce for use in 2001 and
newer model year light-duty motor vehicles (which include passenger
cars, light-duty trucks, and medium-duty passenger vehicles such as some
sport utility vehicles).2 If other state, Federal, and industry practices also
support this introduction, E15 may become available in the marketplace.
As a result, EPA anticipates that some UST system owners and operators
may choose to store higher percentages of ethanol in their UST systems.
In the JulvS. 2011 Federal
Register, EPA published
guidance regarding
compatibility of underground
storage tank (UST) systems
with biofuel blends. The entire
Federal Register notice (signed
by Mathy Stanislaus, Assistant
Administrator, Office of Solid
Waste and Emergency
Response on June 17, 2011)
includes general information,
background, response to public
comments, and the final
guidance. For convenience,
here is the final guidance
excerpted from the Federal
Register.
The guidance discusses how
owners and operators who
wish to store gasoline
containing more than 10
percent ethanol or diesel
containing more than 20
percent biodiesel in their UST
systems may demonstrate
compliance with the
compatibility requirement in 40
CFR 280.32. The guidance
reflects public comments EPA
received as a result of our
November 17. 2010 Federal
Register notice of draft
guidance.
Please note that EPA's partial waiver under the CAA has no legal bearing on an UST owner or operator's
requirement to comply with all applicable Federal UST regulations, including the UST compatibility
requirement in 40 CFR 280.32. Specifically, in order to ensure the safe storage of higher ethanol and
1 See 74FR18228 (April 21, 2009).
2 See 75FR68093 (November 4, 2010), and 76FR4662 (January 26, 2011).
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&EPA
Office of Underground Storage Tanks, Washington, D.C. 20460 June 2011
www.epa.gov/oust
biodiesel blends, or any other regulated substance, owners and operators must meet the existing
compatibility requirement for UST systems.
The UST compatibility requirement in 40 CFR 280.32 states, "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." Because the chemical and physical properties of ethanol and biodiesel blends may make them
more aggressive to certain UST system materials than petroleum, it is important that all UST system
components in contact with ethanol or biodiesel blends are materially compatible with that fuel.
UST System Components That May Be Affected by Biofuel Blends
To be in compliance with 40 CFR 280.32, owners and operators of UST systems storing ethanol-blended
fuels greater than 10 percent ethanol or biodiesel-blended fuels greater than 20 percent biodiesel must
use compatible equipment. EPA considers the following parts of the UST system to be critical for
demonstrating compatibility:
• Tank or internal tank lining
• Piping
• Line leak 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 sumps and under dispenser containment)
• Release detection floats, sensors, and probes
• Fill and riser caps
• Product shear valve
For newly installed equipment comprised of multiple individual components such as submersible
turbine pump assemblies, UST system owners and operators may obtain a certification from the
equipment manufacturer documenting compatibility for the entire assembly. If equipment requires
maintenance and components of that equipment (for example, sealants and gaskets) are subsequently
added or replaced, manufacturer approval of the overall component is not sufficient to demonstrate
compatibility.
Options for Meeting the Compatibility Requirement
Acceptable methods for owners and operators of UST systems storing ethanol-blended fuels greater
than 10 percent ethanol or biodiesel-blended fuels greater than 20 percent biodiesel to demonstrate
compatibility under 40 CFR 280.32 are:
• Use components that are certified or listed by a nationally recognized, independent testing
laboratory (for example, Underwriters Laboratories) for use with the fuel stored;
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&EPA
Office of Underground Storage Tanks, Washington, D.C. 20460 June 2011
www.epa.gov/oust
• Use components approved by the manufacturer to be compatible with the fuel stored. EPA
considers acceptable forms of manufacturer approvals to:
o Be in writing;
o Indicate an affirmative statement of compatibility;
o Specify the range of biofuel blends the component is compatible with; and
o Be from the equipment manufacturer, not another entity (such as the installer or
distributor); or
• Use another method determined by the implementing agency to sufficiently protect human
health and the environment. EPA will work with states as they evaluate other acceptable
methods.
Currently, a note in 40 CFR 280.32 allows owners and operators to use the American Petroleum
Institute's (API) Recommended Practice 1626, an industry code of practice, to meet the compatibility
requirement for ethanol-blended fuels. The original version of API 1626 (1st ed. 1985, reaffirmed in
2000) applies to up to 10 percent ethanol blended with gasoline and is not applicable to meet the
compatibility requirement for ethanol blends greater than 10 percent. In August 2010, API published a
second edition of API 1626. The second edition addresses ethanol blends greater than 10 percent and
may be used to demonstrate compatibility for UST systems storing ethanol blends.
If the UST owner and operator is not able to demonstrate that the UST system is made of materials that
are compatible with the ethanol blend or biodiesel blend stored, according to 40 CFR 280.32, the UST
owner and operator may not use the system to store those fuels.
State UST program regulations may be more stringent than the Federal UST regulations. In addition to
state and Federal UST requirements, UST system owners and operators may be subject to other Federal,
state, or local regulatory requirements (for example, U.S. Occupational Safety and Health
Administration, National Fire Prevention Association, and International Fire Code). UST system owners
and operators should check with their state and local agencies to determine other requirements.
If you have questions about this guidance, please contact Andrea Barbery at barbery.andrea@epa.gov
or(703)603-7137.
Dated: June 17, 2011
Mathy Stanislaus
Assistant Administrator, Office of Solid Waste and Emergency Response
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