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Beacon Station 3492 December 27, 2006 Manteca, Californiani Underground Storage Tanks Closure Report Native soil observed in the UST basin sidewall consisted of a moist, brown, silty sand (SM) from below the concrete paving section to the maximum depth observed at approximately 16 feet below surface grade (bsg). Groundwater was not encountered in the excavation. Three soil samples were collected from native soil beneath each UST (Tl -1, 2, 3 and T24, 5, 6) at approximately 15 to 16 feet bsg at the ends and at mid point of each tank as shown on Figure 2. Representative soil samples were collected by hand -driving a clean brass sample sleeve into excavated soil within the backhoe bucket. Field screening for volatile hydrocarbons in these soil samples was conducted with a photo -ionization detector (PID). No field evidence of gasoline hydrocarbons, such as odor or discoloration, was noted in the UST excavation. On December 8, 2006, SJCEHD Inspector Naidu observed pipeline trench excavation and the stockpile sampling activities. Eight soil samples were collected from beneath the product line (PLI through PL5) and vapor line (VL6 through VL8) trenches from approximately 4 to 6 feet bsg at the locations shown on Figure 2. Soil samples were collected by filling brass sample sleeves with hand -auger excavated soil. No field evidence of gasoline hydrocarbons, such as odor or discoloration, was noted in the in the trench excavations. Approximately 172 cubic yards of backfill material, predominantly pea gravel, excavated from the former UST basin and piping trenches was stockpiled on site. No field evidence of gasoline hydrocarbons was noted in the stockpiled materials. Field screening for volatile hydrocarbons with a PID indicated no detectable concentrations. A total of eight soil samples (SP1 through SP8) two-point composite characterization samples were collected from the soil stockpile at the site. Soil Analyses and Analytical Results Soil samples were prepared and transported, under chain -of -custody documentation, to Kiff Analytical LLC, a State -certified (No. 2236) laboratory in Davis, California. The soil samples were analyzed for: total petroleum hydrocarbons as gasoline (TPHg); the volatile aromatic compounds benzene, toluene, ethylbenzene, total xylenes (13TEX); the seven fuel oxygenate compounds methyl -t -butyl ether (MTBE), diisopropyl ether (DIPE), ethyl -t -butyl ether (ETBE), tert-amyl methyl ether (TAME), tert-butanol (TBA), methanol and ethanol by Environmental Protection Agency (EPA) Method 8260B and for total lead by EPA Method 601013. Analytical reports are contained in Attachment B. Soil analytical results are summarized in Table 1 and indicate the following: With the exception of a near -reporting -limit concentration of 0.0056 milligrams per kilogram (parts per million or ppm) TBA reported in soil sample TI -3-16 collected beneath the former Tl UST, no concentrations of TPHg, BTEX or fuel oxygenate compounds were reported in the fourteen soil samples collected beneath the former 492USTrpt Dec06 Project No. 1492.11 2 HORIZON ENVIRONMENTAL INC.