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6-� f The extent of the excavation was determined by a combination of the initial investigation data and soil sampling conducted during the excavation process. when the excavation was completed to predeter- mined dimensions, soil samples were taken of the sidewalls and analyzed for TPH, Benzene, Toluene, Xylene and Ethylbenzene - (BTX&E) . Should the results of the sidewall samples show TPH concentrations in excess of 10 mg/fig, the excavation was extended 10 feet in the area of the sample locations showing the excess TPH concentrations. This process was repeated as necessary until all affected soils were removed or were inaccessible. Once a sidewall sample indicated concentrations of TPH were non- detectable, excavation on that side was ceased and a confirmation soil sample was collected. This confirmation sample was analyzed for TPH (light) , TPH (heavy) , BTX&E, total lead, Ethylene Dibromide (EDB) and volatile organics. Stockpiled soils were sampled to determine TPH concentrations to assign the soils for hazardous or non-hazardous disposal. Soil stockpiles identified as hazardous waste (containing TPH con- centration X1000 ppm) were shipped to Casnalia Resources using uniform hazardous waste manifest documentation. Soil stockpiles designated non-hazardous (containing less than 1000 ppm TPH) were shipped to the Forward Incorporated landfill. All soils shipped to Forward, Inc. were accompanied by completed Bills of Lading. The following is a detailed chronology of. the excavation process: Z,une 26. 1989 WESTON and Decon Environmental, Inc. (DECON) personnel net at the work site to develop site. Health and Safety plans and begin Preliminary preparations for the excavation. Work zones were ?+,t:ablished for the excavation area and a decontamination shed was constructed. WESTON outlined the initial boundaries of the r excavation (Figure 2) per the July 12, 1989 Final Remedial Plan. June 27. 1989 - The ;initial excavation centered around borehole #3 (Figure 2) . Prior to the actual excavation, the uppermost B' of soil was removed and stockpiled next to the excavation area. Removal of this soil was conducted to remove material placed on the excavation site from an adjacent parking garage construction. As a result of the soil removal the ground surface prior to the excavation was five feet below the site's surface elevation. Soils were excavated and stockpiled adjacent to the west side of the excavation. The sidewall.s of the excavation were sampled and designated as Pit-17N, Pit-175, Pit-17E and Pit-17W. The sample coding indicated the 4 pit walls were sampled at 17 feet below the ground surface. Also sampled.were stockpiles lift-1, lift-2, and OVBR-1. Lift 1 was the first lift of excavated dirt and lift 2 was the second. OVBR-1 was the designation for the 5' of top soils removed prior to excava- tion. During all excavation activities, air monitoring was 4 .