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Scott Mansholt - 2 - 6 November 2006 Chevron — Catellus Property The purpose of the Catellus investigation was to evaluate and delineate the lateral and vertical extent of petroleum hydrocarbon impacts as the result of crude oil leaks from the former OVP and/or TAOC pipelines. Borings were advanced and soil and groundwater samples collected for analysis of the petroleum hydrocarbons of concern associated with the former pipelines. Current Investigation In June 2006, thirty-one soil borings were advanced, 45 soil samples and 27 groundwater samples were collected and submitted for analysis. Soil analytical results were compared to the U.S. EPA Region 9 Preliminary Remediation Goals Table (PRGs) and the Regional Water Quality Control Board (Region 2) - Environmental Screening Levels (ESLs) provided in Screening for Environmental Concerns at Sites with Contaminated Soil and Groundwater, 2005 (Interim Final). The analytical results from this investigation were compared to the respective PRGs and/or ESLs to estimate contaminant concentrations in soil, groundwater, and air that are considered protective of human health over a lifetime. Additionally, the Water Quality Objectives (WQOs) provided in the 2004 Regional Water Board document entitled Beneficial Use-Protective Water Quality Limits for Components of Petroleum-Based Fuels were considered in conjunction with the ESLs when determining the extent of affected groundwater. The lowest and most conservative PRG, ESL, and/or WQO constituent concentrations were considered. Soil Results Analytical results for the 45 soil samples collected and submitted for TPH as crude oil (TPHc) and BTEX (benzene, toluene, ethylbenzene and xylenes) constituents reported the following TPHc concentrations: 34 samples were ND (less than the method detection limit), five were less than 100 mg/kg, one was less than 1,000 mg/kg, two at 2,200 and 2,300 mg/kg and two were 13,000 and 17,000 mg/kg. The latter two results were from boring SB-8 at 2-feet and 9-feet, respectively, including benzene ND at <0,63 mg/kg and 0.64 mg/kg reported in these two samples. Separate phase crude oil was observed in SB-8 soil field samples to approximately 15-feet. Other than the SB-8 benzene detections, BTEX was ND for the remaining samples. The residential PRG for benzene in soil is 0.64 mg/kg and the ESL is 0.044 mg/kg; the industrial PRG for benzene is 1 .4 mg/kg. The majority of the polynuclear aromatic hydrocarbons (PAHs) generally, were ND except for samples from borings having elevated TPHc concentrations, in particular the 2-foot and 9-foot samples from SB-8. The PAH results for these two samples exceeded both the PRGs and ESLs for several of the individual compounds. Additionally, the remaining PAHs reported low concentrations at or slightly above the respective MDLs. Of these, two samples from SB-5 and SB-6 were equal to or slightly above the benzo (a) pyrene and naphthalene PRGs and/or ESLs for samples from 4-feet and 6-feet, respectively. Analysis of samples from beneath these depths was ND for PAH compounds. According to the report, TPHc concentrations in soil were identified as follows: • SB-6 at 6-feet - 2,200 mg/kg TPHc; the lateral extent of affected soil surrounding SB-6 has been delineated by nearby up/crossgradient borings SB-5, 7, 36, and 37, and by downgradient borings SB-23, and SB-24.