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4.1 Excavation Procedures Review of historical site data (Pacific Bell As-Builts - Prior consultant reports - drawings) indicated that the former underground storage tank located at the site had a 1000 gallon capacity An excavation measuring approximately 10' L x 6' W x 8'D, was dug to remove the tank and surrounding fill material Following tank removal in 1988, the excavation was backfilled with imported material to grade On November 16, 1994, IT utilized an excavator to remove the tank excavation backfill material, which was stockpiled adjacent to the excavation on polyethylene sheeting for future reinstallation into the excavated area (if analytical results warranted) Prior to field work, the field geologist or IT site representative conducted a tailgate safety meeting to ensure proper site safety precautions were identified and also to conform to the IT site specific health and safety plan Once the backfill (approximately 25 tons) had been removed, the excavation was extended in an attempt to remove the remaining diesel impacted native soils, known to exist at 15 feet below grade A Thermo Environmental Instruments brand photoionization detector (PID) was used to screen the excavated native soils for the release of volatile petroleum hydrocarbons The PID was properly maintained according to the manufacturers instructions and was calibrated at the site prior to initiating field activities The excavated native soils were installed in a 20yd3 secure top roll off bin and in a stockpile (on triple layered visqueen) until characterization and disposal The native soil excavation was extended to the maximum depth practicable based on the limits of the excavator The excavation was extended laterally until utility lines and a nearby vapor extraction well were encountered As the residual diesel concentrations contained in the excavation verification soil samples were below 1,000 ppm diesel (action level), no extraordinary measures were taken to extend the excavation further 4.2 Excavation Verification - Soil Sampling Upon reaching the practical limits of the native soil excavation, verification soil samples were ' coIlected from the walls and the floor of the newly excavated area Samples were collected utilizing the excavator bucket to access the desired sampling locations The excavator bucket was brought to grade and samples were collected directly from the soils in the bucket M7J01-27-95/UST/95-0011 nbr 3