Your underground storage tanks can potentially leak and create a serious, extremely costly pollution hazard. A small leak could go undetected for a long time and cause severe damage to the environment, especially water resources. As past cases have proven, a single incident can result in a multimillion dollar damage settlement.

The integrity of an underground storage tank (UST) has become a concern countrywide. Many housing authorities use underground storage tanks to store oil, gasoline, and other liquids that can present pollution exposure. Many underground tanks are constructed of bare steel. This offers no corrosion protection and buried bare steel corrodes rapidly. Inadequate backfill and poor pipe fittings are examples of installation mistakes that result in leaks.

There are a variety of ways to help prevent underground storage tanks from leaking or to detect leaks when they occur. Some of these are presented below.

Preventative measures

 Cathodic Protection: If your underground tanks are made of steel, cathodic protection is needed to reduce corrosion. There are several different types of cathodic protection systems, but the general principles remain the same. Their purpose is to introduce into the soil a second metal more electrically active than steel. This will cause the decay of the metal in the cathodic protection system instead of the tank. You should not depend on the tank’s coating as a substitute for cathodic protection. Coated steel tanks should never be installed without cathodic protection. However, tanks which are made of nonmetallic, noncorrodible material such as fiberglass reinforced plastic or other noncorrodible materials do not require cathodic protection.

Underground Liners: A liner impervious to the substance being stored can be placed below the tank. It prevents the leaking substance from reaching the ground water.

Schedule Tank replacement: Replace tanks before they reach their expected life, according to the manufacturer’s or installer’s recommendations.

Monitoring Wells: Where ground water is close to the surface, wells can be dug and sensors placed on the surface of the ground water. These sensors detect the presence of hydrocarbons and warn when a leak has occurred.

Leak Detection

Inventory Control: One method of detecting tank leaks is a daily inventory of tank contents. This is possible only if the volume going in and out of the tank is metered.

It must be determined if a discrepancy is actually caused by a leak. Temperature change, evaporation, or theft can also be responsible for a decrease in volume. In most cases, a leak will show a constant discrepancy, while a loss due to other causes will be sudden and periodic.

The federal government and many states have passed legislation regulating underground storage tanks. If your state has not done so, it most likely will in the near future. Check with your state authorities to examine the regulations that have been passed. Meanwhile, it is a prudent choice to follow and comply with the regulation that is the most stringent.

Precision Leak Test: A precision leak test, which can detect a leak as small as 0.06 gallons per hour, can help you determine the integrity of your underground tank and piping system without excavation.

Spill and Overfill protection: The purpose of spill and overfill protection equipment is to eliminate the potential for a release during fuel deliveries. The equipment must be in working order and used properly to provide adequate protection from spills and overfill. Periodic spills over a period of a year can result in a significant area of contaminated soil. Proper maintenance of this equipment is essential in decreasing the possibility of contamination.

Underground Tanks

A large number of companies are available to test tanks with varying degrees of accuracy. There are many different types of testing equipment and contractors. Before you have someone test your underground system, confirm that their test(s) will comply with all the requirements of NFPA 329. This will ensure that the test equipment used is capable of producing accurate results.

Even with all the prevention and detection discussed, do not assume your exposure has gone away. You still have work to do. There is still a need for continued monitoring to be assured that the systems in place are functioning and that early warning devices are operational to prevent future release.