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observations did note what appeared to be petroleum-affected soil within Tank #4 excavation. The analytical results are summarized in Table A-1, Appendix A In January of 1990, petroleum-affected soil was excavated from the former Tank #3 ' area by WHF Environmental Consultants (WHF) The excavation extended partially into Union Street encompassing a rectangular area of approximately 500 square feet to a depth of ' approximately 25 feet bgs Approximately 550 cubic yards of soil were removed from the excavation and remediated off-site at 1320 West Weber Street, Stockton. Soil samples were ' collected from the north, east, south, and west walls of the excavation at approximately 20 feet bgs, as well as on the northern and southern floor of the excavation at approximately 25 feet bgs (Figure A-1, Appendix A) The samples were analyzed for oil and grease, TPH-E, TPH- G, and BTEX The analytical results of the historical soil sampling are presented on Table A- 2, 2, Appendix A. Oil and grease (200 mg/kg) and ethylbenzene (57 pg/kg) were detected in the ' south floor sample, while 285 mg/kg oil and grease was detected in the northern wall sample Based on these soil concentrations and visual observations, WHF estimated the total volume of residual contamination to be 12 5 cubic yards of soil at 111 mglkg oil/grease and 20 pg/kg ethyl benzene (WHF Quarterly Groundwater Report - December 1992, February 1993) The excavation was backfilled with "clean" pea-gravel On March 2, 1990, in response to the direction of the San Joaquin County Health Department, WHF resampled the soils at former Tank #1, #2 and product lines area using a ' drill ng. The samples were analyzed for TPH-G, TPH-E, and BTEX compounds. No compounds were detected in the samples collected (WHF, Phase R Remedial Work Plan, ' August 19, 1991). ' In January of 1992, further work was performed by WHF to determine the vertical extent of petroleum-affected soils m the vicinity of former Tanks #3 and #4 A soil boring was drilled near the vicinity of each tank (B-1 for Tank #4 and MW-1 for Tank #3, ' Figure 2). Bonng B-1 was drilled to a depth of 35 feet bgs, while MW-1 was drilled to a ' depth of 75 feet bgs and completed as a groundwater monitoring well Soil samples collected at approximate 5-foot intervals were analyzed for oil and grease, TPH-E, TPH-G, and BTEX- The soil samples collected from MW-1 at 20, 40 and 55 feet bgs were also analyzed for lead The analytical results of soil samples from borings B-1 and MW-1 are presented on Tables A-3 and A-4, Appendix A, respectively. Oil and grease was detected in the sample LrPt 2 1