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e y TPHg and benzene. Groundwater samples from well MW-6 were reported to contain 980 ug/l TPHg and 9 ug/l benzene. In May 1994, GTI drilled five borings (SB-1 through SB-5) on-site to further define the extent of hydrocarbons in soil in the areas of the eastern pump island, former USTs, and former used oil UST. Thirty-seven soil samples collected from the borings were analyzed. The maximum concentrations of TPHg and benzene (15,000 mg/kg and 160 mg/kg, respectively) were reported in a sample from boring SB-4, in the former UST pit. Groundwater was reported at a depth of 43 feet bgs. In November and December 1995, GTI drilled three borings (SB-6, SB-7, SB-9), installed one monitoring well (MW-7), and obtained groundwater grab samples from borings MW-7 and SB-9 to further define the extent of hydrocarbons in soil and groundwater. GTI reported maximum concentrations of TPHg and benzene (640 mg/kg and 1.4 mg/kg, respectively) in a soil sample from soil boring SB-9 at 40-1/2 feet bgs. Results of groundwater grab sampling indicated 1,900,000 ug/l TPHg in MW-7 and 260,000 ug/l in boring SB-9. Benzene was reported as non-detectable in both groundwater grab samples. In October 1997, PACIFIC installed two wells (MW-8 and MW-9) to define the extent of gasoline hydrocarbons in groundwater downgradient of the site and vertically adjacent to the former UST complex. PACIFIC reported maximum concentrations of TPHg and . benzene (6,200 mg/kg and 110 mg/kg, respectively) in a soil sample from 35 feet bgs in well MW-9. Maximum reported concentrations of TPHg and benzene in soil from 65 to 75 feet bgs in well MW-9 were 8.1 mg/kg and 0.063 mg/kg, respectively. Soil results from well MW-8 reported non-detect TPHg and BTEX concentrations. Initial groundwater samples were collected from well MW-8 and MW-9 on October 6, 1997. Concentrations of TPHg and benzene in well MW-8 were reported at 370 ug/l and 19 ug/l, respectively. Concentrations of TPHg and benzene in well MW-9 were reported at 130,000 ug/1 and 20,000 ug/l, respectively. MtBE was not detected. Between September 5 and 9, 2000, SECOR conducted assessment activities to further characterize site hydrogeology and evaluate the lateral and vertical extent of hydrocarbons in groundwater both on-site and off-site. According to the CPT data collected during this assessment, the site hydrogeology consists of mainly fine-grained sediments with intermittent sandy interbeds. Based on both current and historical soil analytical data, it appears that the majority of hydrocarbons in soil are in the vicinity of the former gasoline USTs (SB-4, MW-9, and HP-4). Hydrocarbons have impacted groundwater in the vicinity of the former gasoline USTs (MW-1, MW-2, and MW-9), and have migrated downgradient to the area of MW-5 and MW-7. (Separate-phase petroleum hydrocarbons have been detected floating on groundwater in MW-9 during the two most recent quarterly groundwater monitoring events.) Non-detectable to low concentrations of hydrocarbons were detected in wells MW-3, MW-4, and MW-6. Low