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In February of 1991, as required by the SJCPHS, BAI completed an investigation of the site as documented in an April 1$ 1991 Report f p p t o Findings One monitoring well, two piezometers and four soil borings were completed as part of this ' investigation During this investigation, soil contamination by diesel constituents was determined to exist adjacent to the diesel UST excavation At this time, no detectable concentrations of Total Petroleum Hydrocarbons as diesel (TPHd) were ' reported in a groundwater sample obtained from monitoring well MW-1 which was verified to be located downgradient of the excavation In addition, the former ' gasoline UST is unlikely to have caused a discharge, based on the absence of detectable gasoline constituents in the soil samples collected in proximity to the former gasoline tank This work was completed according to the workplan dated February 4, 1991 In December 1991, BAI completed a remedial excavation of contaminated soils ' Approximately 1,100 LCY of soil were excavated and stockpiled on-site No detectable concentrations of TPHd were reported in soil samples obtained at the perimeter of the excavation, except for a single sample adjacent to the restroom and ' a sample on the west side of the excavation whose concentrations were reported to be 40 mg/kg and 1 7 mg/kg, respectively The sample on the west side of the excavation was overexcavated, but further excavation at the restroom location was limited due to the potential excavation instabilities and potential damage to the restroom structure During the excavation, the groundwater in the excavation was observed to have a floating product sheen Also, the piezometer on the east side of the excavation (P-1) was destroyed by excavation as documented in a letter dated January 27, 1992 After ' the completion of the remedial excavation, the piezometer on the west side of the excavation (P-2) was developed for use as a monitoring well Results of this excavation are documented in a February 17, 1992 Report of Construction This work was completed according to the workplan dated October 24, 1991 Two groundwater sampling events undertaken after the remedial investigation ' have reported no detectable petroleum hydrocarbons in either of the two existing wells (MW-1 and P-2) ' 2.0 SOIL INVESTIGATION METHODS AND RESULTS 21 SOIL SAMPLING METHODS On September 29, 1992, BAI advanced four borings using a manually driven auger in order to obtain three samples from native soils in the vicinity of the restroom as shown in Figure 1 These locations were chosen to determine the extent of 2 IF40 _ _ I