SITE INFORMATION AND CORRESPONDENCE

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Michael Oliphant -4 - 18 April 2012 NFAR — Catellus, Tracy environmental screening levels and the risk evaluation using the conservative residential exposure scenario, residual crude oil present in soil should not result in an unacceptable health risk for an adult or child resident. According to Chevron's risk screening evaluation findings, the most likely exposure scenario is dermal contact by future maintenance/trench excavation workers within the area of affected soil near/within the utility corridor at the Site. Avoiding the known affected areas by future excavations could reduce/minimize potential direct contact with residual TPH compounds that remain at the Site. Summary: Based on the findings, including a health risk screening evaluation, it is anticipated that the residual crude oil remaining would not present an unacceptable risk of direct human exposure for the residential exposure scenario. The concentrations of residual crude oil compounds present at the Site are highly immobile, limited in extent, and will continue to naturally degrade with time, likely over several years. Consistent with SWRCB Resolution No. 92-049, an evaluation of alternative cleanup technologies other than natural attenuation are ineffective, not easily implemented, and/or disproportionally costly in comparison to benefits. The site specific SGMP acts as a management reference designating Chevron as the responsible party if any affected soil or groundwater confirmed to be related to the historical pipelines is encountered during future construction/utility maintenance work. A copy of the SGMP was provided to the owners of property determined to overlie the areas of affected soil/groundwater. There are no groundwater monitoring wells associated with the Site. The comments received during the public comment period of 30 days were noted and included in the project files.