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At the suggestion of Mr. Steve Sasson of PHS/EHD, Stockton Mortgage elected to assess the extent of contamination by utilizing a backhoe to excavate the soil. EXCAVATION PROCEDURES Stokeley Construction of Tracy, California was retained to perform the excavation. Excavation took place on October 31, 1995, and was supervised by Upgradient Environmental. Upgradient screened the excavated soil with a portable photo-ionization detector to identify contaminated soil. After approximately 1 hour, the backhoe uncovered a sheet of Visquine at a depth of approximately 3 feet; this appeared to have been laid in the excavation to separate contaminated from uncontaminated soil. However, during the first two hours of excavation, only very low PID concentrations (3-7 ppm) were detected. At the end of this time, the excavation was approximately 7 feet deep. This non-contaminated soil was stockpiled west of the building. When the excavation reached a depth of 7 feet, moderate gasoline odors were noted in the southeastern comer of the excavation, and the backhoe began segregating this soil from the non- contaminated soil. The contaminated soil was stockpiled west of the excavation. During the next two hours, PID concentrations increased from 222 ppm to more than 2500 ppm as the depth of the excavation was increased to 13 feet. A decision was made at that time to discontinue further excavation and collect one soil sample for laboratory analysis. The sample was collected from the backhoe bucket, using a percussion slide hammer loaded with brass sample sleeves. One sleeve was covered with Teflon sheets, capped, and transported in a cooled ice chest to Sequoia Analytical Laboratories in Sacramento. The excavation was then backfilled with the non-contaminated stockpile and pea gravel that had been delivered during the excavation activity. The contaminated stockpile (30 tons, approximately 40 cubic yards) was transported to REMCO's disposal facility in Richmond, California. Copies of the load manifests are attached to this report. EXCAVATION RESULTS The laboratory analyzed the sample for the presence of gasoline and volatile aromatic hydrocarbons. It was also analyzed for reactivity, corrosivity, and ignitability per REMCO's request. As shown in the attached laboratory report, gasoline-range hydrocarbons were detected at a concentration of 14,000 mg/kg (parts per million). This concentration is approximately twice that which was detected in the most contaminated sample that was collected during the tank removal in 1993, at an estimated depth of 5 feet. Fortunately, however, benzene, a known carcinogen, was not detected. Other volatile compounds were detected at concentrations ranging from 37 mg/kg (toluene) to 340 mg/kg(xylene). The laboratory described the chromatogram pattern of the sample as typical of weathered gasoline.