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Two soil samples were collected "from the contaminated area" by EHD staff on April 26, 1991 for analysis. Staff from EHD then contacted the Tracy Fire Department (TFD) to inquire as to whether there were any underground storage tanks (USTs) registered to the property and TFD personnel indicated that no USTs were registered to the property; however, three aboveground tanks (ASTs), including one 1,500-gallon gasoline AST, one 2,000-gallon diesel AST, and one 250-gallon solvent AST previously existed at the Site. Staff from EHD screened the soil with a PID and the soil appeared to contain concentrations of VOCs. Based on Partner's experience, the solvent likely refers to mineral spirits or other petroleum hydrocarbon-based material. Subsequently, the on-site soils engineer was interviewed regarding the stained and odorous soils previously noted. The soil engineer stated that the soil was taken from an old septic leach field and that the septic tank had previously been removed. The soils engineer also mentioned a 15-foot deep dry well "that was filled with a 2 sack cement slurry". The EHD's notes mention that EHD staff were onsite to "observe well destruction" and that "drillers...began work on the well destruction". The maximum concentrations of petroleum hydrocarbons from the two April 26, 1991 soil samples were: 1900 milligrams per kilogram(mg/kg)TPH-d, 500 mg/kg total petroleum hydrocarbons as gasoline (TPH-g), 0.7 mg/kg toluene, 2.6 mg/kg ethylbenzene, 12.5 mg/kg xylene, 123 mg/kg total chromium, 10 mg/kg lead, and 35 mg/kg zinc. On May 3, 1992,EHD staff collected two soil samples from the excavated soil that was stockpiled at an off-site location. The maximum concentrations of petroleum hydrocarbons from the two May 3, 1991 soil samples were: 170 mg/kg TPH-d, 1.7 mg/kg TPH-g, 0.005 mg/kg toluene, 0.012 mg/kg ethylbenzene, and 0.037 mg/kg xylenes; no metals were analyzed. Based on a review of the EHD's 1991 field sketch, two building foundations are shown with a "closed well" to the north of the southern-most building foundation. The "contaminated area", is shown as being 80 feet long in the north-south direction and 40 feet in an east-west direction, is indicated as being 300 feet northwest of the "closed well". Based on the field sketch and an 1982 aerial photograph from Partner's Phase I ESA report (included in Appendix E) it appears that the "closed well" depicted in the EHD field notes may be related to a structure that is within the east- central portion of what was to become the Site and that the northern building foundation may be related to a structure shown to be just to the southwest of the intersection of North Tracy Boulevard and Clover Road. Given these observations,the inferred location of the"contaminated area"would be approximately 160 feet south of Clover Road and 290 feet west of North Tracy Boulevard as shown on Figure 2. The June 10, 1991 SCS letter to the CVRWQCB states: On April 29, 1991, as part of the preliminary investigation, SCS collected three grab soil samples. The samples were analyzed for total petroleum hydrocarbon (TPH), using EPA Protocol 418.1. The results of the analysis ranged Sampling and Analysis Workplan Tracy Corners Shopping Center 3225 North Tracy Boulevard Tracy,California 95376 Partner Project Number SM14-129814 Docket Number HAS-VCA 14/15-108 August 15,2016 Page 7