What’s underground

Underground storage tanks, which can hold 50,000 gallons, most often — but not always — contain petroleum products. These are among chemicals and compounds in underground tanks:

* Gasoline, diesel fuel, kerosene, aviation fuel.

* Pesticides.

* Herbicides.

* Chemicals to be used in manufacturing processes.

* Waste liquids such as oils, plating solutions, solvents, waste paints, thinners.

Health threats

The most common hazard in underground tanks is benzene. Some industries use benzene to make other chemicals, which are in turn are used to make plastics, resins, and nylon and synthetic fibers. Benzene also used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Benzene is a natural part of crude oil, gasoline, and cigarette smoke.

Eating or drinking foods containing high levels of benzene can cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsions, rapid heart rate, and death. The major effect of benzene from long-term exposure is on the blood. Benzene causes harmful effects to bone marrow and can cause a decrease in red blood cells, leading to anemia. It can also cause excessive bleeding and affect the immune system, increasing the chance for infection.

Benzene contamination increases the risk of cancer.

Sources: U.S. EPA; Agency for Toxic Substances and Disease Registry