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Lo GEOMATRIX LM Manual. The evaluation required the conservative assumption that the oil-affected soil is exposed at the ground surface and that residents are exposed to the maximum concentrations of chemicals detected in the soil. The health risk assessment concluded that potential exposure to the soil affected by crude oil/Bunker C oil would not result in unacceptable health risks to ,r.. future on-site residents. The DTSC approved the conclusions of the human health risk assessment in a memorandum dated November 3, 1995. Based on the risk assessment results for the Dividend property and the fact that concentrations of petroleum detected at the Dobler property are lower than those at the Dividend property (2 100 mg/kg TPH vs. 7500 mg/kg TPH), the residual petroleum at the Dobler property should pose no significant risk to future on-site residents or commercial workers. A copy of the closure letter dated June 29, 1999 from PHS-EHD for the Dobler Property is attached as Appendix A to this document. LW SOIL MANAGEMENT PLAN 1" This management plan is intended to describe options for handling the soil affected by degraded crude oil/Bunker C oil if it is excavated during construction or when placing/repairing belowgrade utilities. The sample location where oil-affected soil was encountered is depicted on Figure 2. The area of known impact does not extend more than 150 feet north of the L, property line and generally occurs between depths of 8.5 and 9.5 feet bgs. REUSE OR DISPOSAL OF EXCAVATED SOIL L. Because the residual crude oil/Bunker C oil in soil does not pose an unacceptable risk to human health or the environment, it can be reused at the site. Upon encountering oil-affected soil during excavation, the following steps should be taken: (1)notify Chevron and (2) visually identify, segregate, and stockpile the excavated oil-affected soil on site. Upon notification that V degraded oil-affected soil has been encountered, an Chevron representative will consult with the appropriate party to evaluate the final disposition or reuse options and will inform PHS- ,�, EHD of the status. This consultation process is not intended to stop excavation work, earthwork may proceed during this evaluation. Because a petroleum hydrocarbon odor and x.. crude oil residue may be present in this soil, consideration should be given to where the soil is placed. Potential reuse options include placing the soil back into the subsurface (in trenches and other excavations) or underneath surface coverings (roads, parking areas, or other paved structures). LW The following guidelines are recommended: (1) if used as trench backfill, the oil-affected soil should not be placed in contact with underground utilities or areas that might require future Lo s 3:\DGc_safe13000s13499\3449.0051soil nmgnt plan.doc 3