SITE INFORMATION AND CORRESPONDENCE

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Michael Oliphant - 3 - 18 April 2012 NFAR — Catellus, Tracy Groundwater samples collected from offset borings were submitted for analysis of TPH as diesel (TPHd), BTEX, and PAH compounds. Analyticak results were ND at respective method detection limits and/or did not exceed respective screening levels. Visually affected soil was not observed in drill cuttings or groundwater from the step-out borings. Central Valley Water Board staff concurred in January 2011 that additional characterization was not needed and a request for no further action required could be prepared. • SAIC provided a No Further Action Required Request report (NFAR) for closure consideration 25 May 2011. • Chevron's consultant, SAIC provided a Soil and Groundwater Management Plan (SGMP), dated 25 May 2011. The SGMP describes procedures and contains the contact names and phone numbers for representatives of Chevron and the San Joaquin County Environmental Health Department if future activities encounter crude oil affected soil and/or groundwater. The SGMP serves as a guideline for Chevron to implement for the handling, reuse, and disposal of any crude oil affected soil and/or groundwater that may be encountered at the Site in the future. It provides procedures for property owners, developers, and/or maintenance firms to follow that addresses such topics as trench excavations, dewatering, and health and safety guidelines. • On 13 February 2012, Central Valley Water Board staff provided written notification to the owner(s) of properties overlying and/or within 200 feet of the approximate boundary of affected soillgroundwater defined at the Site. The notification stated that the Central Valley Water Board was considering a No Further Action Required determination for the Site and that comments could be submitted within 30 days. Written comments were received from a representative for one nearby property owner to confirm their understanding that Chevron is the responsible party for residual crude oil impacts from the Site that could be potentially identified in the future. • There are no groundwater monitoring wells associated with the Site. Extent defined: Yes. Estimated Residual Petroleum Mass: Unknown. Petroleum occurs primarily as degraded petroleum hydrocarbons in soil at approximate depths of between 5 and 13 feet bgs. The highest TPHc concentrations of 20,000 and 24,000 mg/kg were detected at depths of 5 and 8 feet bgs respectively, in borings beneath/near the former pipeline. Analytical results for deeper samples from the same borings at deeper depths tc 29 feet bgs and other delineation borings were ND for TPH compounds. Threat to Groundwater: The historical pipelines were removed from service more than 40 years ago. The lateral and vertical extent of each affected groundwater area overlaps and is larger than corresponding affected soil areas. Affected groundwater has been defined beneath the historical crude oil pipelines, under the highway, within the UPRR and highway easements, extending slightly offsite primarily downgradient and southeast on to adjacent undeveloped land and rural properties and has been defined. Chevron's consultant conducted a well search survey of Department of Water Resources records. Approximate locations for ten domestic water supply wells were noted within about a one-half mile radius of the Site. One of the wells was sampled during a site investigation on an adjacent OVP/TAOC project and TPH compounds were not reported. Similarly, an undocumented onsite private well was sampled and TPH compounds were not detected. The remaining wells were about 700 to 1,200 feet downgradient or cross gradient, some distance from the estimated delineation outline boundary of affected groundwater. Municipal water supply for any future development of the area will likely be provided by the City of Tracy Public Works. Threat to Human Health: SAIC's risk screening evaluation determined the aggregate cancer risk for exposure to onsite soil was 4E-06, which is within the acceptable risk range of 1 E-06 to 1 E-04 and does not present an unacceptable risk for a residential exposure scenario. In addition, the non-cancer hazard of 3E-03 is well below the acceptable health hazard value of 1. Based on the applicable