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Historical Background Information: West Clay Properties Page 3 of 7 November 2003 - preparation for excavation of petroleum hydrocarbon-impacted soil at the site, extraction well EW-1 was destroyed by over-drilling the well to total depth 10-inch augers. December 2003 - Petroleum hydrocarbon-impacted soil was excavated at the site by Valued Engineering of Stockton, California, utilizing an excavator. Soil was excavated to an approximate depth of 25 feet bsg at the former gasoline UST Cluster area. Excavated soil was screened using an OVM, excavated soil was segregated into impacted soil and clean soil. Only soil exhibiting hydrocarbon odor or measurable OVM readings was stockpiled for final disposal;the clean soil was used to backfill the excavation. Approximately 340 cubic yards (486 tons) of impacted soil was excavated from the former UST Cluster area as part of remedial action at the site. On 19 December 2003, approximately 486 tons of petroleum hydrocarbon-impacted soil was transported to Forward Landfill in Manteca, California for disposal. The clean overburden was sampled, analyzed and utilized as backfill material. Additionally, 20 individual soil samples were collected from the soil stockpile. The samples were shipped to CTEL and subsequently composited and analyzed. Soil stockpile samples SP-01, 05, 09, 13 and 17 were in individually analyzed. • Five soil samples (EX1-N, EX1-E, EX1-S, EX1-W and FLR-01) were collected from the sidewalls and floor of the former UST excavation. In addition, five composite soil samples and five individual soil samples collected from the soil stockpile generated during excavation activities were submitted for laboratory analysis. Fuel oxygenate MTBE was detected in sidewall soil samples EX 1-E and EX 1-S at concentration of 0.010 milligrams per kilogram (mg/kg) and 0.050 mg/kg, respectively. Other target analytes were not detected in the two samples. In addition,analytes of concern were not detected in sidewalls samples EX1-N and EX 1-W and floor sample FLR-01. • TPH-g was detected in the five composite soil stockpile samples at concentrations ranging from 10 mg/kg to 13 mg/kg. Various concentrations of BTEX constituents were detected in the same samples at concentrations as high as 0.44 mg/kg benzene,0.44 mg/kg toluene,0.97 mg/kg ethylbenzene and 1.94 mg/kg total xylenes. In addition, MTBE was detected in two composite soil samples at concentrations of 0.015 (SP-13, 14, 15, 16) and 0.011 mg/kg (SP 17, 18, 19, 20). Other fuel additives and lead were not detected above laboratory reporting limits in any of the samples analyzed. • Based on relatively high OVM readings,AGE had anticipated higher detected concentrations of analytes in the composite soil samples.To confirm the OVM readings,one individual soil sample from each composite sample (SP-01, SP-05, SP-09, SP-13 and SP 17). TPH-g was detected at concentrations ranging from 86 mg/kg to 3,300 mg/kg. BTEX constituents were detected at concentrations as high as 1.5 mg/kg benzene,3.0 mg/kg, 33 mg/kg ethylbenzene and 197 mg/kg total xylenes. • The mass of petroleum hydrocarbons removed in soil was determined on the basis of the averaged concentrations of TPH-g in the soil samples collected, AGE's calculations estimated that approximately 992 lbs or 159 gal of gasoline were removed from the site Advanced GeoEnvironmental,Inc.