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'=fs HISTORY OF SITE WORK Initial UST Removal, Overexcavation, and Sampling Activities On April 21, 1993, two, 10,000-gallon capacity, leaded gasoline underground storage tanks and one, 5,000-gallon capacity, diesel underground storage tank (USTs) were removed from the subject site. Evax Technologies, Inc. inspected the tanks and .� collected soil samples from beneath the ends of each leaded gasoline UST, and one sample from beneath the fill end of the diesel UST immediately subsequent to removal. All samples were retrieved from the floor of the excavation at 13.5 feet below surface grade (bsg). Additionally, two soil samples were collected from the soil stockpile flanking the excavation. The stockpile was moved to the south end of the property. Analytical results of the soil samples revealed that elevated levels of Total Petroleum Hydrocarbons as gasoline (TPH-g); Total Extractable Petroleum Hydrocarbons as diesel (TEPH-d); volatile aromatics benzene, toluene, ethylbenzene, xylenes (BTEX); and lead were present in the samples collected from the excavation and from the "-' stockpile. The overexcavation of the former tank pit was undertaken on July 16, 9993 by W.W. Irwin, Inc.. The work was periodically supervised by Mr. Michael Collins, SJCPHS- EHD Registered Environmental Health Specialist. As the excavation proceeded, soil samples were collected for lithologic analysis and organic vapor analysis (OVA) meter readings were taken in order to direct the excavation.. The excavation was expanded slightly in all directions from the original tank pit to an area approximately 35 square feet and to a depth of approximately 18 to 20 feet below surface grade (bsg). The excavation was halted when the excavator reached the limits of its extension and the northern wall became inaccessible. Groundwater was not encountered. An estimated 260 cubic yards of excavated soil was removed from the tank pit and stored at a location on the south side of the property, and separately from soil stockpiled during the tank removal operation. The excavation was backfilled in May of 1994 subsequent to collection of stockpile soil samples for single-sample-composite analyses. Backfilling was approved in a letter dated May 10, 1994 from Specialist Collins to Mr. Dwight Davis of the Pegasus Group. F:7.1 HydropunchTM Sampling On April 8, 1994, three HydropunchTm boreholes (HP-1, HP-2, and HP-3 depicted on Figures 2 and 3) were drilled near the north, east, and west flanks of the J i DAYNE L. FRARY, GEOLOGIST 2 1296-012.197 :j