Nearby the spill was an old tank battery. All of the tanks had long since been removed but the original containment berm was still in place. The soil in the berm was free of hydrocarbon or salt contamination. In May, 1996 the contaminated soil was excavated and replaced with soil form the berm. The excavated soil was land treated within the confines of the old tank battery using standard methods with the addition of hay and N-P-K fertilizers. After 46 days of treatment average TPH levels were reduced to about 7,000 mg/kg on average. The most recent TPH measurements (June, 2001) showed residual concentrations ranging from 2,000 to 9,800 mg/kg.

Both the land treatment cell and the excavation site have partially revegetated since active intervention ceased. This poster compares the current status of the two disturbed sites relative to unimpacted prairie in terms of aboveground biomass of grasses and forbs and species diversity.