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for ty 16 September 1996 AGE-NC Project No. 95-0168 Page 3 of 5 samples collected from the excavation are summarized in Table 2. Copies of the laboratory report �. (MAI Laboratory Nos. 55550 through 55563) and chain-of custody are included in Appendix B. 3.2. DRILLING AND SAMPLING { On 05 June 1996, two soil borings were drilled at the site. Each boring was drilled using a truck- mounted HT-55 drill rig equipped with hollow-stem augers. The drill rig and a two-man crew was supplied by Soil Explorations Services,Inc of Rancho Cordova, California.Boring B 1 was advanced at a 20° angle, under the southern edge of the building on-site.B2 was advanced at a 10° angle under the western edge of the building on-site. Both borings were advanced to 25 feet bsg. Soil samples were collected ahead of the drill bit using a split-tube sampler loaded with three pre- cleaned 2-inch by 6-inch brass sleeves. Samples were collected at five-foot interval's, using a 140- pound hammer to advance the sampler 18 inches. The number of blows required to advance the LW sample in 6-inch increments was recorded on the boring log. To avoid cross-contamination, the sampling equipment was washed in an Alconox solution and rinsed twice with water prior to each sample run. Augers were steam-cleaned between borings. . The leading soil-filled sleeve in the sampler was preserved for laboratory analysis. Both ends of the lead sleeve were covered with Teflon sheets, capped and sealed with tape. The samples were stored in a chilled container and transported under chain-of-custody to McCampbell Analytical Laboratory, Inc. (MAI)of Pacheco,California. Selected samples were analyzed for TPH-g, BTE&X and methyl- tawtert-butyl ether(MTBE) in accordance with EPA methods 5030, 8020 and 8020, respectively. During drilling, auger returns were monitored for the presence of organic vapors using a photo- ionizing detector (PID: Thermo Environmental 580A, 10.0eV calibrated using isobutylene). 3.3. LOGGING Soil was extruded from the second brass sleeve and screened for the presence of organic vapor using Aaw a PID and the readings were recorded on the boring logs. Filed observation of the soil from boring B1 yielded no PID values and soil from boring B2 contained detectable organic vapors at 10 and 15 feet. The soil was then described'in accordance with the Unified Soil Classification System. Boring logs are included in Appendix C. A stratigraphic cross section of the soil encountered at the site, including the estimated area of hydrocarbon-impacted-soil is depicted in Figure 3 -Cross Section. LWr Primarily,silty clay was encountered at the site.Based upon a soil sample submitted for geotechnical r analysis,the clayey soil appears to have a lower permeability and adequate organic content to reduce