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Lee Higgins -4 - 7 December 2010 Chevron, TAOC Tracy Rail Yard sample from a depth of 16.5 feet bgs. Reportedly, bunker fuel was used to facilitate crude oil movement through the historical pipelines. According to the Report, TPH affected soil was present at depths greater than 11 feet bgs to a depth of approximately 20 feet bgs. The affected soil was present along the east-west length of OU-2, adjacent to and about 200 feet north of the former TAOC pipeline alignment. The lateral extent west of OU-2 is addressed below in sections OU-3, 4, and 5. The vertical extent was defined by analyses of deeper samples from depths of approximately 22 to 27 feet bgs, which were ND for TPH, and where visually affected soil was not observed in drill cuttings. Analytical results indicated that PAH compounds were detected in 17 of 20 soil samples submitted for analysis. Carcinogenic PAHs were detected in 16 samples where the BaP TEQ's ranged from 0.0016 to 0.16 mg/kg. The highest values (0.14 and 0.16 mg/kg) were for two samples from borings that encountered affected material having elevated concentrations of TPHc which AMEC considered unrelated to the historical crude oil pipelines. The PAH findings will be addressed in a future health risk assessment by UPRR's consultant. The lateral offsite extent of TPH affected soil to the east and south of OU-2 into adjacent residential areas was not defined. This will be addressed by Chevron in future investigations. Groundwater Analysis of a groundwater sample from boring TRY-1 (affected soil discussed above), reported TPHd at a concentration of 2,500 micrograms per liter (Ng/L). According to AMEC, this boring was drilled near a former AST previously located at the northern terminus of a section of the historical OVP pipeline located on the Site. The former OVP entered OU-2 near the southeast corner of the parcel. The highest TPHd detection within the parcel of 22,000 pg/L was of a water sample collected at a depth of 16 to 20 feet bgs from boring TRY-7. A concentration of 1 ,600 mg/kg TPHc in soil at a depth of 16 feet bgs was also reported. Analysis for TPHd of a water sample from the same boring at depths of 23 to 28 feet bgs was 68 pg/L, and BTEX was ND. Low concentrations of PAHs were detected in groundwater, and the BaP TEQ's ranged from 0.0065 to 0.032 mg/kg. The deeper interval defines the vertical extent of TPH in groundwater. In addition, two offset borings were drilled further north, the presumed downgradient direction, to collect groundwater grab samples. Samples were submitted for the same TPH constituents. The analytical result for one sample was ND for TPHd at the method detection limit (MDL). The second boring was not sampled since hydrocarbon affected soil/groundwater was not observed. With the exception of the area along the central-east side of the parcel, the findings define the lateral extent of crude oil affected groundwater within OU-2. Soil Vapor Sampling Two offset locations near prior borings with elevated TPH in soil, and in close proximity to residential areas, were selected (SV-A and SV-B) for soil vapor sampling at depths of five and 10 feet bgs. Four samples were submitted for analysis of BTEX and naphthalene (a PAH compound). According to the results, benzene and naphthalene were not detected at