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UST Program - Ethanol-Blend Fuel Compatibility

UST Program - Ethanol-Blend Fuel Compatibility

March 2000


The purpose of this advisory is to notify you that some underground storage tank and piping (UST) systems may not be compatible with ethanol-blend fuels. As MTBE is phased out of gasoline, ethanol is a likely replacement fuel oxygenate. Gasoline supplied to some parts of California already has ethanol added at concentrations as high as 10 percent by volume. If your UST system is not compatible with this fuel, there is a higher risk of damage to your UST system and the environment. Therefore, we strongly urge you to verify that your entire system is compatible with the ethanol-blend fuel before you store it in your UST system. You may be able to obtain compatibility information from the equipment manufacturer (see list attached). If you are unsure whether your current or future supply of fuel contains or will contain ethanol, you should check with your fuel supplier.

Based on the review of available compatibility testing information, industry literature, and other published research papers, the compatibility of some of the following UST system components with the ethanol-blend fuels should be verified:

    • Single-wall fiberglass tanks installed prior to 1/1/1984
    • Single-wall fiberglass and flexible piping installed prior to 1/1/1984
    • Lining material used to line old single-wall tanks for repairs or upgrade
    • Adhesives, glues, sealants, and gaskets used around the piping and other parts of the UST system (more of a concern for older systems, but may be an issue for the new installations as well if the contractor failed to use proper material)
    • Pump heads and other auxiliary equipment, including certain metals (e.g., aluminum, copper, some brasses/bronzes, etc.), that come in contact with the product
    • Older models of some leak detection equipment that may not operate properly or its parts that may wear out with exposure to ethanol-blend fuels.

If you don't have compatibility records in your files, we strongly recommend that as UST owners/operators you ask the respective equipment manufacturer(s) for a written compatibility statement for ethanol-blend fuels before you begin storing that type of fuel. You should also ask for information regarding maximum concentrations of ethanol that your system can be exposed to, the industry testing standard, and the testing process by which the manufacturer supports the above statement. Keep a copy of this information for your records.

If you have difficulty obtaining this information in writing from the manufacturer you may seek assistance from your local agency. You may address your questions regarding this advisory to your local agency or Shahla Farahnak at (916) 227-4350.



James George Giannopoulos, Chief
Regulatory Programs Branch