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where further delineation was recommended." In 2005, Clayton performed additional site assessment activities and delineated the 13 areas. In 2006, significant remedial efforts were undertaken by SAIC to address the impact to soil by petroleum hydrocarbons. According to SAIC, "impacts noted during previous trenching and soil boring programs were remediated through excavation. Remedial efforts resulted in removal of approximately 131,228 cubic yards of soil from the 13 excavation areas. Confirmation soil sample results collected from the sidewalls and base of the excavations confirmed that the affected soil in the 13 areas had been adequately remediated to levels that were deemed acceptable by the RWQCB." Soil vapor sampling was also conducted by SAIC and included in the 2007 report. According to SAIC, "soil vapor sample results demonstrated that [benzene, toluene, ethylbenzene, and xylenes] BTEX and naphthalene concentrations at the site did not exceed [Environmental Protection Agency] EPA human health risk levels (a cancer risk of less than 1 in a million) and do not constitute a threat to indoor air quality of future buildings at the site." NEIGHBORHOODS B,C AND D 2009 Subsurface Investigation: Conestoga-Rovers & Associates (CRA) performed investigation activities to evaluate groundwater impacts following remedial activities that involved excavating total petroleum hydrocarbon (TPH) impacted soils. A total of 34 monitoring wells were installed in the Neighborhood B, C, and D areas. The monitoring wells were located within and around the excavated areas. Soil analytical results indicated that limited TPH impacts were encountered in the areas investigated. All detected soil concentrations were below the 5,000 mg/kg total petroleum hydrocarbons as crude oil (TPHc) and petroleum hydrocarbons as diesel (TPHd) cleanup goal except one sample collected from well boring MW-6 in Neighborhoods C and D (Area 5, Excavations 8 and 9). The 25 fbg sample contained 23,000 mg/kg TPHc and 11,000 mg/kg TPHd, which exceeded the RWQCB excavation goal of 5,000 mg/kg (excavation goal referenced in RWQCB letter dated January 22, 2009). The 20 and 30 fbg soil samples define the extent of these impacts to below laboratory reporting limits. According to SAIC's March 13, 2007 Remedial Action Report, Area 5 (Excavations 8 and 9), was excavated to a total depth of approximately 18 fbg. Approximately, 8,689 cubic yards of impacted soil was excavated. The bottom sample TPHc and TPHd concentrations were 360 and 150 mg/kg, respectively. More 060222(11) B-3 CONESTOGA-ROVERS&ASSOCIATES