University of Wisconsin - Extension

Underground storage tanks, used for vehicle fuel and heating oil on farms and rural residences throughout Wisconsin, can pose serious problems if they are neglected. Experts estimate that there are more than 9,000 leaking underground fuel storage tanks in Wisconsin.

"The Wisconsin Department of Commerce, which regulates storage tanks, estimates that underground gasoline tanks begin leaking after 12 to 17 years,? says Tom Blewett, University of Wisconsin-Extension Community Resource Development assistant program leader and waste reduction specialist.

?Even small leaks can add up to big problems,? explains Blewett. ?A tank leaking one drop every 10 seconds could release 60 gallons per year. Unfortunately, it takes only a few quarts of gasoline to severely contaminate a family?s drinking water or a nearby steam or lake. One gallon of gasoline can contaminate up to 10 million gallons of water."

Groundwater contamination also can occur from leaks or spills from above-ground tanks for gasoline, diesel fuel and home heating oil.

"The most conspicuous problem is the odor or taste of water tainted by a spill or leak, but some elements of fuel such as benzene, a carcinogen, can be dangerous at levels below those that can be detected by smell or taste," Blewett adds.

The financial risks of a leaking underground fuel storage tank can be overwhelming. Typical cleanup costs for buried, leaking tanks ranges from $10,000 to $100,000 for commercial and private sites.

Smaller underground storage tanks, less than 1,100 gallons, must be upgraded, replaced or closed by May 1, 2001. Many smaller farms have gasoline or diesel fuel storage in smaller underground storage tanks. Heating oil tanks over 4,000 gallons also must be upgraded, replaced or closed by May 1, 2001. Heating oil tanks less than 4,000 gallons not in compliance with current EPA underground regulations must be upgraded, replaced or closed by May 1, 2006.

Farmers may call the Department of Commerce for help at the following numbers: Adams - Eau Claire (01-18), call (608) 267-2051. Florence - Marquette (19-39), call (608) 267-1383. Milwaukee - Rusk (40-54), call (608) 276-5280. Menominee and St. Croix - Wood (55-72), call (608) 267-1382.

The Wisconsin Department of Commerce Bureau of Storage Tank Regulation can provide more information regarding storage tank regulations, including installation and removal requirements.