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USEPA 8015C Total Petroleum Hydrocarbons as Diesel and Motor Oil Range Organics (TPH-D/MO) All analyses were conducted by Sunstar Laboratories, a California-certified analytical laboratory, with standard turnaround on results. 4.0 RESULTS OF INVESTIGATION 4.1 General Subsurface Conditions Boring logs for the four borings are included in Appendix B. Soils encountered in the four borings generally consisted of silts, sands and clays down to total boring depths. These soil units were generally not correlative between borings. No groundwater was encountered in the four borings, and no hydrocarbon odors or OVM detections were noted in soils from the four borings. 4.2 Results of Laboratory Analyses Soil laboratory analytical results are summarized in Table 1 and on Figure 3, and the laboratory data report for soil analyses is contained in Appendix C. Soil samples from the four investigative borings showed no significant hydrocarbon detections. The only hydrocarbon detections were: 15 milligrams per kilogram (mg/kg) of Total Petroleum Hydrocarbons as Diesel (TPH-D) at 20 feet in depth in B-1; 30 mg/kg of TPH-D at 30 feet in depth in B-1; and 12 mg/kg of TPH-D at 15 feet in depth in B-4. 5.0 CONCLUSIONS Results of this investigation indicate no significant hydrocarbon impacts from the possible operation of a gas station on the Site prior to the mid-1950s. Soils in the four investigative borings showed no field evidence of hydrocarbons, and laboratory analytical results from soil sampled down to 30 feet in depth in the four borings showed no significant hydrocarbon detections. Based on these results, it appears that the possible operation of a gas station on the Site in the late 1940s or early 1950s does not represent a Recognized Environmental Condition relative to the Site. We recommend no additional investigation relative to environmental conditions on the Site. Page 5 3310 & 3330 E. MAIN ST., STOCKTON, CA PHASE II ENVIRONMENTAL SITE ASSESSMENT