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Corrective Action Closure Report June 11, 1993 BP Chemical Facility (SJCEHD Site Code 2042) Page 4 Analytical Results The analytical results are presented on Tables 1 and 2, and the laboratory data sheets are attached. As shown on Table 1, with the exception of total xylenes in Sample 1SW, concentrations of petroleum fuel hydrocarbons in samples from sidewalls of the final extent of excavation are below cleanup objectives. The sample from the southern wall (Sample ID 1SW) contained a residual concentration of total xylenes (0.023 parts per million [ppm]) which is very near the cleanup object (0.015 ppm). Because the detected concentration of total xylenes in Sample 1 SW was very low and nearly at the cleanup objective, the southern extent of the excavation was not extended. Residual concentrations of ethylene dibromide were not reported above the method detection limit (MDL) in any of the excavation sidewall or excavation bottom soil samples tested. Total lead concentrations ranged from below MDL (5 ppm) to 5.9 ppm. Samples from the stockpiled soil were also analyzed (Table 2). Low concentrations of petroleum hydrocarbons were detected in the stockpiled soil samples analyzed. Total lead concentrations ranged from 4.5 ppm to 42 ppm. A letter summarizing the soil sample analytical results was prepared and submitted to the SJCEHD (letter dated February 3, 1993). In a February 23, 1993, telephone conversation, Ms. Margaret Lagorio of the SJCEHD gave approval to backfill the excavation. Also, the SJCEHD requested that, because the analytical results of a sample from one of the soil piles reported a total lead concentration of 42 ppm, an additional soil sample from that pile be collected and analyzed for soluble lead (WET Test). The analytical results (fable 2) of the stockpiled soil sample (SP-2) reported a soluble lead concentration at the detection limit of 0.5 milligrams per liter (mg/1). SITE CLOSURE ACTIVITIES Excavation Backfilling On April 26, 1993, the UST excavation was backfilled with existing clean backfill material from the site. A SJCEHD representative was present at the beginning of the backfilling activities to examine the source of the clean backfill material, and to observe the sampling of the stockpile that contained total lead concentrations of 42 ppm. The clean soil was placed in the UST excavation and compacted using a backhoe. No further backfilling of that excavation will be required. Stockpiled Soil The soil excavated during the tank removal and overexcavation activities (except for the soil stockpile tested for soluble lead) was spread out to approximately a one foot thickness at the site. Because of the CACR0074.DK GROUNDWATER TECHNOLOGY, INC.