UNDERGROUND OIL SPILL INVESTIGATION AND CLEANUP1

ABSTRACT In April 1978, the U.S. Environmental Protection Agency (EPA) Region I office received an oil spill report which involved a sheen leaching from an industrial park into a river in Connecticut. Initial investigation revealed only two 10,000-gallon and one 11,000-gallon buried storage tanks as possible sources. All were located relatively close together about 200 feet from the river. The maintenance man reported that one of the 10,000-gallon tanks had spilled an estimated 500 gallons into the ground the previous year. EPA responded and initially worked with the property owner and the Connecticut Department of Environmental Protection in addressing the problem. Although the leaching seemed to be relatively minor at first, it gradually increased after July 1978. The property owner was unable to finance cleanup actions after the first few months. EPA assumed cleanup responsibility, using federal funds, and eventually took over all investigation and recovery efforts in 1980. The incident has involved many phases, including locating and estimating the volume of the underground contamination, attempted source identification through sample analysis, installing recovery systems, excavating the oil storage tanks, winter operations of the recovery systems, disposal of product, and river cleanup. Analyses of test boring data in 1979 indicated the maximum volume of spilled product on the groundwater to be between 50,000 and 150,000 gallons. Since 1980, the recovery systems alone have yielded more than 90,000 gallons of oil, making this innocuous incident one of the largest inland oil spills ever in Region I. It also has been the most expensive federally-funded inland spill in the region. Recovery from the groundwater is expected to continue through 1982, albeit at a decreasing rate. The total observed volume of oil involved in the spill will probably exceed 110,000 gallons.