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Stantec No Further Action Request Report Chevron and ARCO Commingled Plume No. CP0034 April 10, 2012 analytical data is presented in Table 3. Locations of historical sampling locations are included in Figures 5-20. The station was renovated to include additional dispenser islands and product lines in late 1996 to early 1997. Soil samples taken from beneath the product lines at depths of three and four ft bgs reported a maximum concentration of 8.1 mg/kg GRO and 0.29 mg/kg of benzene. Approximately 200 cubic yards of hydrocarbon-impacted soil was transported to BFI Landfill in Livermore, California for disposal (Chevron, 1997). The site was demolished and five USTs were removed in June 2005. The USTs were disposed of at Ecology Control Industries in Richmond, California. Additionally, a 1,000-gallon concrete UST was discovered in the northwest portion of the site during grading for the new station. The concrete UST was crushed onsite and disposed of with the remaining site debris. A total of nine UST confirmation soil samples TP-1 through TP-5 were collected at 12 feet bgs from each end of the individual USTs. Soil samples were also collected from beneath the dispensers (D-1A through D-6A and D-1B through D-6B) and the product lines (PL-1 through PL-13) at depths between three and five ft bgs. One soil sample was collected from each end of the 1,000-gallon concrete UST. GRO, benzene, toluene, ethylbenzene, and xylenes (collectively BTEX), or fuel oxygenates were not detected above the laboratory MRLs in the soil samples collected beneath the product lines and dispensers. In the tank pit soil samples, only methyl tert-butyl ether (MTBE) was detected at a maximum concentration of 0.026 mg/kg (TP-2). One of the two soil samples collected from the ends of the 1,000-gallon concrete UST contained 1.5 mg/kg GRO, 0.001 mg/kg ethylbenzene, and 0.009 mg/kg total xylenes (TP-6N). Two new USTs (30,000 and 15,000 gallons), dispenser islands, and a station building were constructed in June 2005 (SECOR, 2006). Historical soil analytical data is presented in Table 3. Historical figures depicting the locations of the soil samples could not be located. On January 27, 2008, a small fuel spill was identified by a member of the San Joaquin County Environmental Health Department (SJCEHD) at dispenser no. 13 (northwest corner dispenser) emanating from under the hood. Upon further inspection, it was determined that a small leak was caused by a blown meter gasket above the shear valve. Because the leak occurred above the valve this did not trip the line leak detector present. A small amount of liquid pooled near the dispenser and was cleaned up by store staff using FM-186 and absorbent pads. The spill waste material was placed in a drum and labeled hazardous waste, pending proper disposal by Chevron. On January 29, 2008, a SECOR technician went to the site to verify that no separate phase hydrocarbons (SPH) were observed in monitoring wells (MW-1R, MW-2R, and MW-5R). The field measurements determined that there was no SPH present in those three locations. A UST Unauthorized Release Report was submitted to SJCEHD Certified Unified Program Agency on January 31, 2008 (Secor, 2008). No evidence of hydrocarbon impact to the 94275 NFAR 2012.doc 5