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SamplingReportforRemoval of Hydraulic Oil Tank—P.G.&E,Stockton,CA June,2004 FIELD ACTWTI IES Geo-Logic's field work was performed on June 9 and June 11, 2004. On June 9, 2004, one 1,000- gallon double walled steel hydraulic oil tank was removed from the location shown on Figure 1. The piping which extended from the tank to the garage building had previously been removed. The tank, which had a fiberglass coating, appeared to be in good condition. The soils exposed on the excavation sidewalls consisted of brown silt. The backfill material consisted of pea gavel. After tank removal, it was determined that there was a concrete hold-down slab beneath the tank at a depth of approximately nine feet below grade, or approximately one foot beneath the tank bottom. Mr. Dennis H. Catanyag of the San Joaquin County Environmental Health Department SJCEHD and Mr. Kent MlIer of the Fire Department witnessed the tank removal. Because shoring the excavation would be required to complete sampling beneath the concrete slab, as required by the SJCEHD, sampling beneath the tank was not completed on the day of removal. One sample, labeled as PI (3'), was collected from beneath the hydraulic oil piping at the depth indicated. The samples were collected from approximately two feet into native material, which consisted of brown silt. Also, a two-part composite sample was collected from the stockpile of excavated soils. Some asphalt was present within this material. Mr. Catanyag of the SJCEHD witnessed this sampling. The locations of the sample point beneath the piping is shown on Figure 1.No evidence of hydrocarbon contamination was observed in any of the samples or in the piping trench or tank pit excavation. The liners containing the samples were capped, labeled, and stored in a cooled ice chest prior to same- day delivery to the laboratory. On June 11, 2004 Geo-Logic returned to the site to conduct sampling beneath the hydraulic oil tank. At that time, the excavation had been shored and the remaining pea gravel backfill material had been removed. The concrete tie-down slab was approximately the same dimension as the hydraulic oil tank in the longest direction, and therefore samples were obtained directly adjacent to and beneath the slab, approximately two feet into native material. These samples, designated as TN(12') and TS (12'), were collected from beneath the two tank ends at approximately twelve feet below grade, at the locations shown on Figure 1 The samples were collected by driving brass liners directly into bulk material excavated by hand auger. Ms. Mnchelle Le of the San Joaquin County Environmental Health Department witnessed the sampling. No evidence of hydrocarbon contamination was observed. 2