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implementing agency 30 days before storing the fuel. Owners and operators must also keep
records demonstrating that their UST system is compatible with the substance stored. Ensuring
compatibility of UST systems with these fuels—knowing the materials that make up the UST
system will maintain their respective chemical and physical properties when in contact with the
substance stored —is essential. Storing a fuel that is not compatible with the UST system may
jeopardize the integrity of the UST system and cause a release to the environment.
Demonstrating compatibility of an UST system means identifying what equipment is installed as
part of your UST system. You must show that a component is approved by either the
manufacturer of the component or by a nationally-recognized independent testing laboratory,
such as Underwriters Laboratory (UL), for use with the fuel to be stored. See details about
these requirements in 40 CFR 280.32. Please note that compatibility extends beyond the fuel
tank. Owners and operators must demonstrate compatibility for the components below to
store substances containing more than 10 percent ethanol or more than 20 percent biodiesel.
•	Tank
•	Piping carrying product from the tank
•	Piping containment sumps entered by the piping
•	Pumping equipment, including the submersible pump or suction pump, depending on
the type of system
•	Release detection equipment, including automatic tank gauging (ATG) probes, sump
sensors, and line leak detectors
•	Spill equipment, such as spill buckets, for the tank
•	Overfill equipment, including ball float valves or flapper valves
The federal UST regulation does not require owners and operators to demonstrate the
compatibility of dispensers or associated aboveground equipment. However, compatibility
requirements for these components may exist in other local regulations, such as the fire code.
Owners and operators should check for these requirements with their implementing agency.
To learn more about compatibility compliance requirements, see EPA's website:
•	2015 UST regulation www.epa.gov/ust/revising~underground~storage~tank~regulation~
revisions-existing-requirements-and-new
•	Plain language booklet about compatibility www.epa.gov/ust/ust~svstem~compatibility-
biofuels
•	Questions and answers about compatibility and pipe dope and sealants
www.epa.gov/ust/underground~storage~tank~ust~technical~compendium~about~2015~
ust~regulation#compatibility
•	Emerging fuels and USTs www.epa.gov/ust/emerging~fuels~and~underground~storage~
tanks-usts
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What Are The Compliance Concerns?
Compliance concerns include those related to the compatible storage of ethanol-biofuel blends
containing more than 10 percent ethanol in UST systems.
Disclaimer
This compliance advisory addresses select provisions of EPA regulatory requirements using
plain language. Nothing in this compliance advisory is meant to replace or revise any EPA
regulatory provisions or any other part of the Code of Federal Regulations, the Federal Register,
or the Solid Waste Disposal Act. For more information on underground storage tanks, see EPA's
website www.epa.gov/ust. For more information on enforcement, see EPA's website
www.epa.eov/enforcement.
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