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C- VATC ASSOCIATES I NC . Gasoline Tanks In January 1997, two gasoline USTs were removed from the northwest portion of the property and soil samples were subsequently collected from the open excavation (see Figure 2). Only one sample was reported to have contained TPH as gasoline (TPHg) above laboratory detection limits. Composite samples of the stockpiled excavated soil were collected and analyzed for TPHg, benzene, toluene, ethylbenzene, xylenes (BTEX), and methyl tert-butyl ether (MTBE). Because laboratory results did not detect any of the analytes above the laboratory detection limit, the stockpiled soil along with clean pea gravel and Class A/B subbase was used to backfill the excavation. On February 23 and 24, 1999, ATC supervised the advancement of four soil borings (SB6, S137, S138, and S139) in the vicinity former gasoline USTs (Figure 4). Drilling was conducted utilizing a hollow stem auger drill rig. Soil borings S136 through SB8 were advanced and sampled to 36.5 feet bgs. Soil boring S139 was advanced and sampled to 41.5 feet bgs. Of the fourteen soil samples collected from soil borings S136, S137, S138, and S139, none were reported by the laboratory to contain TPHg, BTEX, or fuel oxygenates above laboratory detection limits. Analytical results of soil samples are summarized in Table 1. In correspondence dated June 25, 1999, PHS/EHD requested additional work at the site to further define the lateral extent of diesel contamination in the vicinity the former diesel USTs. METHODS AND PROCEDURES To further define the lateral extent of diesel petroleum hydrocarbons in the vicinity of the former diesel USTs, a total of two (2) angled soil borings are proposed at the site. These soil borings will be placed east of the former diesel USTs in the vicinity of SB-3. All field activities will be performed in accordance ATC's Site Safety Plan and Quality Assurance/Quality Control Plan (QA/QC Plan) submitted to PHS/EHD on February 1, 1999. Soil Boring Advancement and Sampling Drilling activities at the site will be performed by V & W Drilling (State C57 license no. 720904) utilizing a truck mounted Geoprobe® rig employing DPT. The two proposed soil borings will be completed at depths of 25 feet bgs and advanced at an approximate angle of 30 degrees from vertical. Soil samples will be collected from the two borings at four-foot intervals in acetate sampling tubes and described according to the Unified Soil Classification System. The soil samples and any drill cuttings will be characterized for soil w:\17292\reports\workp1=.doc 3