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S PROJECT BACKGROUND The former Mobil Oil Bulk Terminal is presently a fenced, vacant lot, located on the south side of East Grantline Road at an elevation of approximately 33 feet above mean sea level (NGVD-1929) . Adjacent properties are either vacant or commercial and industrial developments . In 1988, Mobil Oil Corporation abandoned the former bulk storage and distribution plant. All structures were removed from the property including one underground gasoline tank and four aboveground diesel fuel storage tanks . In August 1988, following removal of the underground gasoline storage tank, two soil samples and one ground water sample were collected and analyzed for fuel hydrocarbon constituents . Soil and ground water analytical results detected the presence of total petroleum hydrocarbons (TPH) , and benzene, toluene, ethylbenzene, and xylenes (BTEX) . On November 21, 1988, six exploratory borings were drilled to depths ranging from 12 to 13 feet below grade at the site. Analyses of soil samples collected from depths of 5 and 10 feet showed detectable concentrations of TPH as diesel (TPH-D) up to 2 ,900 parts per million (ppm) and TPH as gasoline (TPH-G) up to 360 ppm. Ground water was encountered between 12 and 12 feet below grade. In February 1989, additional soil samples were collected at the site from 12 test holes at depths of 5 and 10 feet below grade using a backhoe. Analyses of soil samples detected concentrations of TPH-D up to 3, 600 ppm and TPH-G up to 170 ppm. Results of the investigative work revealed the presence of diesel-range contamination in the subsurface soil extending to a depth of 10 feet below grade and encompassing an area of approximately 3, 700 cubic feet. Soil analytical data from test holes suggests that gasoline-range hydrocarbon contamination is limited to the northern portion of the site. In February 1990, Mobil Oil Corporation contracted Alton Geoscience to characterize in situ for potential offsite disposal. The results of the soil profiling were to be used during soil excavation to segregate the soil for disposal at the appropriate offsite facilities . On July 9, 1990, soil excavation was initiated. Balch Petroleum, Inc. of Milpitas, California was contracted by Mobil Oil to perform the excavation under the supervision of Alton Geoscience personnel. Based on the results of this insitu soil characterization, approximately 6, 100 cubic tea: