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Scott Mansholt - 4 - 6 November 2006 Chevron — Catellus Property at relatively shallow depths and they are downgradient of the site. Considering the shallow screen intervals, SAIC indicated these wells could possibly be affected by leaks from the OVP and/or TAOC lines. SAIC recommended the following: • Obtain samples from the three nearby domestic wells and submit for analysis of the petroleum hydrocarbons of concern. • Collect and submit a soil and/or groundwater sample for a fuel fingerprint analysis to determine if the petroleum hydrocarbons present are degraded San Joaquin Valley crude oil. • Advance four soil borings approximately 75-feet lateral to SB-8; collect and submit soil and groundwater samples for analysis to define the lateral extent of impacts; to define the vertical TPH impacts at SB-1 and SB-8, collect and analyze samples taken from beneath the maximum depth of affected soil. • Advance a boring near SB-20 to obtain soil and groundwater samples from beneath the maximum depth of affected soil to determine the vertical extent of affected soil and groundwater at that location. • Install eight borings (west) of Byron Road and collect samples to evaluate the extent of affected groundwater upgradient of the site. • Install twelve borings (east) of Byron Road to evaluate the extent of affected groundwater downgradient of the site. Based on the review of the findings: • Confirmation that leaks from the OVP and/or TAOC lines has affected Catellus soil and groundwater and has not been validated by fuel fingerprint analysis. • Elevated PAHs and benzene were reported in boring SB-8 and additional soil and groundwater characterization is needed; the vertical extent of affected groundwater was not adequately defined in the vicinity of SB-8. • The extent of affected soil has not been defined downgradient of SB-18, SB-20, and SB-51 and additional delineation borings are needed. • The vertical and downgradient extent of affected groundwater has not been defined in the vicinity of SB-1. • Generally, with the exception of the areas described above, the extent of affected groundwater has not been adequately defined upgradient and/or downgradient.