Ethanol Blended Fuels May Present Problems to Some Underground Storage Tanks

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With the introduction of ethanol alcohol to replace MTBE in gasoline comes the problem of storage tank compatibility. Gasoline blended with 10%, 15%, and now 85% ethanol may not be compatible with many older fiberglass and lined steel tanks.

The push is on from state-to-state to eliminate the MTBE in gasoline and replace it with ethanol. This 10% ethanol / 90 % gasoline fuel is known as E10. Ethanol, an alcohol distilled mostly from corn crops, is the same liquor moonshiners made in “stills” back in the early 1900’s, especially during prohibition. Not far behind, with over 900 retail outlets already in the USA, is E85 fuel, which is 85% ethanol and 15% of a gasoline-like hydrocarbon primer. A number of the cars and light trucks built since 1998 can run on this fuel product. Each year a wider base of models are being produced as “E85 compatible” vehicles.

There has been a lot written lately about the pros and cons of the E10 and E85 fuels. Whether ethanol fuels are good for the environment, economy or corn farmers isn’t the issue addressed here. We were looking for information about another ethanol fuel issue – the problem some underground fuel tanks have storing E10 and E85. We had heard that there were tanks out there that are not compatible with the alcohol-blended fuels.

I went looking for answers, which took me to Jeff Colner of the Armor Shield Tank Lining Network. This network of specially trained tank lining applicators has served the storage tank industry since the late 1960’s, and has lined thousands of fuel storage tanks for such companies as ExxonMobil, Chevron, Shell and Texaco as well as hundreds of regional and local companies with fuel storage tanks.

We asked Jeff who should be concerned about the compatibility issue, “As a rule of thumb, fiberglass tanks, and single-wall fiberglass and flexible piping installed prior to 1/1/1984 should be investigated to find out if they are compatible before changing over to the newer blended fuels. Also, if a steel tank has been internally lined in the past, checkout the paperwork just to make sure the lining product is compatible to contain what you’re going to be storing in it.”    

Jeff added, “In addition, there were some adhesives, glues, sealants, and gaskets used around the piping and other parts of older UST systems that should be a concern, and may even be an issue for some new installations if the contractor failed to use proper materials.”

He continued, “Technically, some older fiberglass tanks and lined steel tanks were made or lined using resins that can’t be immersed in these alcohol-blended fuels for an extended length of time without loosing structural integrity and possibly failing. Tanks made or lined in the 1970’s and early 1980’s have a chance of not being compatible with alcohol fuels, and tanks made or lined even years after that may have trouble with the higher alcohol content E85.”

“Over a period of time these un-compatible tanks or linings can “pickle”, or saturate with the alcohol product, loosing strength and other necessary physical characteristics.    An un-compatible fiberglass tank may be a ticking time bomb when used to store alcohol blended fuels, and an un-compatible lining system on a steel tank can fail, making the tank legally non-compliant and susceptible to failure at previously repaired pitted and permeated areas.”

When asked if all of these un-compatible tanks should be removed from the ground and not used for storing alcohol blended fuels, Jeff commented, “Well, that’s a decision to be made by the tank owners and their professional advisors. Also, the individual States may have some input to how to handle this situation. From my perspective, the first thing that tank owners should do is determine whether their tanks are set to store alcohol blended fuels, and that’s not always easy.”

When ask why, Jeff continued, “Different companies used different resin materials to make their fiberglass tanks or steel tank lining material. Some manufacturers were using compatible material during the same time others weren’t, so there aren’t hard dates when tanks started being compatible. Also, there are many different types of lining materials manufactured. Some independent lining companies out there may have used materials blended to line heating oil tanks, which is a big part of the tank lining market. These products may be fine even for gasoline with non-alcohol additives, but once the switch to ethanol blends is made, you’re definitely in un-chartered waters.”

“The good news is that there is a fix, and it does not involve having to permanently remove the tanks from service. Fiberglass tanks can be entered, re-gel coated with ethanol compatible materials, and returned to service. Lined steel tanks can basically be upgraded in the same manner, putting a compatible top layer on the existing lining system. In most cases this only takes the tanks out of service for a few days.”

In ending our phone interview, I asked Jeff if the governmental agencies overseeing tanks used for fuel storage had made any public statements about this problem, where the general public was mostly unaware. He told me, “In March of 2000, the California State Water Resources Control Board issued an Advisory to Underground Storage Tank Owners/Operators Regarding Ethanol-Blend Fuel Compatibility. The purpose for this advisory was to notify tank owners that ‘some underground storage tank and piping (UST) systems may not be compatible with ethanol-blend fuels’. The office of the Illinois State Fire Marshal issued an advisory to let tank owners know that components of their fuel delivery system may not be compatible with E85, even if it is compatible with E10. Also, the Iowa Department of Natural Resources released a bulletin titled ‘Converting Existing Underground Storage Tank (UST) Systems to Ethanol Compatible’. Most of the States have publications or bulletins that included the issue of tank compatibility. No, when the dust settles on the ethanol compatibility issue, it will be the actual tank owner that is ultimately responsible for whatever happens to their tanks."

To get more information on Armor Shield Tank Lining services log on to, or call their customer service hotline toll-free 1-888-839-0373.

Interview conducted by C.R. Manning

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