The Hazards of Old Capped Oil Tanks

Old fuel tanks, even if no longer in use, can pose health and environmental hazards to those living near the tanks. In some cases, if the tank is partially filled, or filled with volatile fuel oil fumes, the old tanks can even create an explosive hazard. Property owners are responsible for tanks on their land whether the tank is in use or not. Before purchasing a property, buyers should have a thorough inspection which includes looking for the presence of old oil tanks.

Potential Tank Leakage

• Steel fuel oil tanks were commonplace household fixtures before natural gas pipelines were laid across the nation, and liquid propane technology was developed. Inexpensive, less volatile and easy to transport, tanks for home fuel oil were installed in a home's basement, or outside both above and below ground near the home. According to home inspectors, a common life expectancy of buried oil tanks is 10 to 15 years. After 20 years, a buried tanks is more likely to leak as the corrosion eats at the seams from the outside of the tank, and any condensed water collecting in the bottom of the steel tank creates oxidation from within. Damage can be catalyzed at any time during the tank's life span as a result of tank damage that may have occurred during installation.

Soil Contamination

• Metal fuel oil tanks eventually corrode, which leads to the possibility of leakage. The average tank was designed for up to 20 years of use, and after this threshold passes, the likelihood of tank leakage increases substantially. According to Fuel Oil and Oil Heat Magazine, a survey in New England carried out during 1984 to 1985 among customers with buried heating oil tanks, surveyors found an average of 1.7 fuel tank leaks per 1,000 customers, and 2.5 fuel line leaks per 1,000 customers. Fuel oil leakage into the soil is considered a hazardous material spill. Cleanup is very expensive, and regulated by federal statutes.

Groundwater Contamination

• A small amount of fuel oil can contaminate a large amount of ground water. The fuel oil does not disperse or dissolve in the water. Rather, it stays on the surface of the water, and thereby contaminates water, and underground organic materials. The consequences of few gallons of fuel oil leaching into a ground water supply results in contaminating the ground water for hundreds of customers. In a recent study in Maine, a state where over 50 percent of residents get their drinking water from ground water sources, a single fuel oil contamination travels an average of 75 feet from the contamination source.

Disposal and Removal Liability

• The owner of a property is responsible for the removal and cleanup of any existing tank and contaminated ground. This means the tank must be removed from the ground, and any contaminated dirt treated as hazardous material and removed from the property as well. In the event of a property sale, once a property is purchased, the liability for any existing or future tank leaks becomes the responsibility of the new owner. For these reasons, an existing, non-functional tank should be removed by an owner before property is sold. Functioning tanks should be replaced with a double wall, above ground tank that can be closely monitored during their lifetime.