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Ms Marla Guensler Exxon Company U S A May 8, 1996 Page 2 Previous analytical results reported residual petroleum hydrocarbon constituents in this area Approximately 150 cubic yards of soil were generated during overexcavation activities Soil samples (Tank Pit-5 through Tank Pit-7) were collected from the side walls of the overexcavation and from the base of the excavation (Tank Bottom) for chemical analysis Soil sample locations are shown in Figure 3 The soil samples collected on December 29, 1995, were submitted to Sequoia Analytical laboratory for analysis of BTEX and TPH as gasoline using the previously mentioned methods Analytical results for samples collected on December 29, 1995, are summarized in Table 1 A copy of the laboratory analytical report with chain of custody documentation is included in Enclosure A During the overexcavation of the north end of the new tank basin area vapor extraction well VW-2 was exposed and removed, with the approval of the San Joaquin County Environmental Health Department on-site representative Stockpile SamR!= During the excavation/overexcavation of soil in the new tank basin area, approximately 700 cubic yards of soil was generated An additional 62 cubic yards of soil was generated during the excavation of the new product distribution line trenches An estimated total of 762 cubic yards of soil was generated The excavated soil was characterized for disposal by collecting four soil samples per 100 cubic yards which were composited by the laboratory prior to analysis Each composite sample was analyzed for BTEX and TPH as gasoline using the previously mentioned methods, and total lead using EPA Method 6010 A summary of the stockpile soil sample analytical results are summarized in Table 1 and a copy of the laboratory analytical report with chain of custody documentation is included in Enclosure A Soil generated during excavation activities was transported under non-hazardous waste manifest by Dillard Trucking Inc (Dillard) to BFI Waste Systems in Livermore, California Excavated soil was transported off-site during four separate events On January 9 and 10, 1996, Dillard reported that 400 and 272 cubic yards were transported during each event, respectively On January 26 and 31, 1996, Dillard reported 108 cubic yards were transported during each event A total of approximately 888 cubic yards of soil was reported transported by Dillard Copies of the waste manifests are included in Enclosure B The discrepancy between the estimated volume of soil sampled (762 cubic yards) and the reported amount of soil transported (888 cubic yards) by Dillard was based on weight Because the soil was wet, additional trucks were required Each truck reported 18 yards of soil (by weight), however the volume was less (approximately 15 5 cubic yards) due to the saturated condition Discussion Analytical results indicate that residual petroleum hydrocarbons constituents are present in the area of the new tank basin Delta has installed soil vapor extraction (SVE) piping and well boxes for possible future remedial activities, if warranted The locations of SVE piping and well boxes are shown on Figure 4 and details for the SVE piping are illustrated in Figure 5