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tank location. The augers were steam cleaned prior to drilling^each boring. Soil generated during the drilling process was added to the soil piles already stacked at the site. A sand -cement slurry was used to refill the boreholes D-1 , 2, 3 and.4 at the former diesel tank location. Boring D-5, which was drilled through excavation backfill was filled with the drill cuttings. 4.2 Soil Sampling Soil samples were collected through the auger in two and a half (2 112) inch diameter brass sleeves driven in a split-spoon sampler by a 140-pound hammer with a 30-inch drop in accordance with ASTM methods-D1586-84 for split-barrel sampling of soil and D1587-83 for thin-walled tube sampling of soils. Prior to sampling, the core barrel was loaded with three brass sleeves. In general, upon collection, the middle sample sleeve was capped, sealed, labeled in accordance with EPA protocols, recorded on a Chain-of-Custody form, and stored in an iced cooler at four degrees centigrade (4°C) or less, pending analysis by Zymax Envirotechnology (hydrocarbon analyses) or BC Laboratories (inorganic analyses), California State Certified Laboratories. The bottom and top sample sleeves were used for lithologic description and for field screening. The soil samples were collected at-five foot intervals beginning at a depth of five feet, with the exception of Boring D-1 , the angle boring, in which case it was more convenient to retrieve the samples at five foot intervals starting at seven feet. The blow 1 counts, recovery, and lithology were recorded on field boring logs. The lithology was described in accordance with the Unified Soils Classification System and ASTM procedure D2488-84 for visual description and identification of soils. 4.3 Field Screening of Soil Samples A portion of soil from each core sample was placed in a sealable plastic bag for approximately 5 minutes. The probe of the Foxboro Model 128 OVA/GC Hydrogen Flame-ionizing detector (FID) was then inserted and a standard headspace reading was taken and noted on the boring logs. In addition, AGI's mobile laboratory was on- site to provide field analytical results. This unit is equipped with a SRI Instruments Gas Chromatograph which is presently configured to provide quantitative (but not certifiable) results for the aromatic fuel constituents (benzene, toluene, ethylbenzene, and xylenes) and Total Petroleum Hydrocarbons referenced to gasoline. Diesel fuel hydrocarbons contain some volatile hydrocarbon components which overlap the gasoline range and therefore, diesel can usually be recognized on the chromatograms generated, but the results provide only a qualitative identification of diesel. The use of the Mobile lab provided an on-site interpretation of the.presence of fuel hydrocarbons in the samples. Chromatograms generated in the field are included in Appendix B. 5