Special Topics in Environmental Management

Biofuel Considerations: Safe Handling of Ethanol—For Your Tank

Ethanol is a renewable, domestically produced fuel that can be made from grains, such as corn or wheat, or from cellulose sources, such as prairie grass or agricultural, forestry, or municipal wastes. In the United States, ethanol is primarily made from corn.

EPA’s Office of Underground Storage Tanks regulates tanks storing petroleum and biofuels. Under EPA UST regulations, USTs must be compatible with the fuel stored. States administer the UST program, and compatibility is the responsibility of the tank owner.

There is much controversy about the extent of damage that ethanol can do to your storage tank, however, no one debates that E85, E15, and all midlevel ethanol blends between the two required special considerations related to storage, dispensing, handling, and vehicle operation, as compared to gasoline.

Tank owners and operators must take precautions before adding a high percent ethanol blend, such as E85, to a storage tank. Following are eight tips for converting a UST for E85 and three tips for maintenance of the tanks.


Attend the Ethanol and Biodiesel in Your ASTs and USTs webinar on April 15 to learn how to prevent and respond to tank damage from alternative fuels. Learn more.


Tips for Converting a UST for E85

  1. Notify your licensed installer (some states do not require installers to have a license) and the state UST program of your intent to dispense E85. Print a copy of the statement of compatibility from your tank manufacturer.
  2. Notify your UST insurance carrier to determine whether it has additional requirements for E85 fuels.
  3. Obtain an amended insurance certificate showing coverage of E85 storage and dispensing.
  4. In the case of a conversion, clean the tank of all water and sediment. Ensure no water is present to protect the quality of your ethanol-blended fuels and your customers’ vehicles. Standards that are helpful when cleaning a tank include API Publication 2015, Cleaning Petroleum Storage Tanks, and NFPA 326, Standard for the Safeguarding of Tanks and Containers for Entry, Cleaning, or Repair, 2010 Edition.
  5. Ensure all visible fittings and connections at the top of the tank are tight (no vapors escape and no water enters).
  6. Ensure the sump and spill containment covers will prevent water from entering the system. Identify the E85 fill port and paint the access cover according to API RP 1637 (the API color-symbol system for marking equipment and vehicles). Make certain transport drivers cannot make fuel deliveries to the wrong fill pipe. Misfueling is a concern for vehicles older than model year 2001.
  7. As a precaution to address residual sludge and gum deposits that will be dissolved by ethanol, industry recommends the tank to be filled to 80% of capacity and kept as full as possible for 7 to 10 days. The residual impurities will be more diluted in a larger quantity of E85, reducing the risk of vehicle problems. This practice is also likely to expose any problems related to sludge and gum deposits during the initial inspection period.
  8. Conduct a precision test of the tank system (0.1 gallon/hour leak rate) with an automatic tank gauging system within 7 days after the tank is filled, to confirm the integrity of the system and that the leak detection equipment is operating properly. Report any fail results as required by the agency that has jurisdiction over your UST.


Ethanol and Biodiesel in Your ASTs and USTs: How to Prevent Corrosion and Achieve Compliance

Properly store alternative fuels in both aboveground and underground storage tanks while maintaining compliance with regulations. Register today!


Maintenance Tips for USTs Storing E85

  1. Check for water regularly. Ensure that no water is contaminating your fueling system. If water is suspected or detected, track down its source and fix the problem immediately. The best way to guard against contamination is to properly clean and maintain the fueling system. Confirm no leaks exist in the tank fill cap and containment reservoir before beginning your E85 operation.
  2. If the product seems to pump slowly, check and replace filters. Persistently clogged filters could indicate moisture or another source of contamination.
  3. If installing a blender pump, ensure that the ethanol content is updated in the control system as the percentage changes according to geography and season.