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April 7, 1992 ARCO Service Station No 760, Lada, California Approximately one third of the pea gravel from backfill remained in the hole. Soil excavated from the new tank cavity was then placed on top of the geofabnc We observed the excavation of the new tank cavity to 12 feet below grade on June 19, 1991 The limits of the new tank cavity are shown on Plate 3 The excavated soil was placed on the geofabnc in the former tank cavity The soil was later sampled and characterized, as discussed below We observed Golden West excavate a trench to approximately 12 feet below grade from west to east across the new tank cavity to obtain samples of native soil Soil samples S-12- T4, S-12-T5, S-12-T6, and S-12-T7 were collected before the new tanks were installed The sample locations are shown on Plate 3 In addition, soil samples S-12-T6N and S-12-T6S . were collected from the northern and southern limits of the new tank cavity 1 On June 19, 1991, a 550- alhon_tank_{designated T8 onPlate-3 was uncovered south of the sample trench while excavating the remaining area of the new tank cavity The tank contained soil and liquid Our geologist placed the PID probe inside the fillport of the tank and recorded a reading of 400 parts per million by volume A sample of the liquid (labeled W-6-T8) was collected by lowering_a teflon bailer into the tank The liquid was submitted to the laboratory 1 Golden West obtained a permit from the SJCPHS-EHD to remove the tank RESNA observed the removal of tank T8 on June 21, 1991 r geo- gis note a Western_ Oil qCo� y -=ignxa--on the -tan.� and a label that indicated the tank- formerly contained oh e At ARCO's request, the tank was transported and disposed of by H and H Shipping Services With authonzation from the SJCPHS-EHD, we observed the contractor excavate 4 feet below the former tank to 12 feet below grade, the final depth of the new r � 38048-5 8