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i Manifest Representatives of the PHSIEHD and the Stockton Fire Department were present during the tank removal As observed during tank removal, the diesel tank was manufactured of steel and there were no signs of corrosion or leakage from the tank ' After the tank was removed, the excavation was visually inspected and soil samples were collected by a Kennedy/Jenks representative The excavation was approximately 16 feet ' wide by 12 feet long by approximately 10 feet deep No staining was observed in the tank excavation Soil samples collected from the excavation sidewalls and bottom and from excavated soils were analyzed in the field with an organic vapor analyzer Organic vapors were not detected in these samples ' Two soil samples (T-1 , T-2) were collected from native soil at both ends of the excavation at depths approximately 1 to 2 feet below the tank excavation bottom The samples were collected by hand-driving brass liners into soil located in the backhoe bucket The approximate location of the tank excavation and the soil sample locations are shown on Figure 4 A composite soil sample (T-3) was also collected from the stockpiled soil removed from the tank excavation This sample was placed on-hold in the laboratory and was to be analyzed only if chemicals of concern were detected in samples T-1 and T-2 ' Laboratory Analyses Results Soil samples T-1 and T-2 were analyzed on a 48-hour turn- around-time basis for the following constituents • Total Petroleum Hydrocarbons as Diesel (TPH-D) by EPA Method 8015 • Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) by EPA Method 8020 ' Total Petroleum Hydrocarbons and BTEX were not detected above method detection limits in samples T-1 and T-2 The results of laboratory analyses were discussed with Ms Kasey Folley of the PHSIEHD on 4 May 1990 Ms Folley agreed that the laboratory results indicate that the tank had not leaked and that the tank excavation could be backfilled The tank excavation was backfilled on 10 and 11 May 1990 The bottom excavation was backfilled with pea gravel to approximately 4 5 feet below ground surface Prior to ' backfilling, the excavation was lined with a filter fabric to prevent crossing of native soils The top of the pea gravel was also covered with the fabric before backfilling with soil The stockpiled soil removed from the tank excavation was placed in a low spot in the sales yard ' A complete description of the tank removal was provided in our June 1991 Phase II Investigation and Site Closure Report, Cal-Farm Supply Stockton Facility This report was ' submitted to the Regional Water Quality Control Board (RWQCB) and included recommendations for no further work and for closure of the five Site monitoring wells Groundwater Monitoring Program In October 1992, Ms Whitworth was notified by the RWQCB that additional investigation of ' the tank site would be required In April 1993, she was officially notified, in an undated I 112254000 3 922540 00 04/26/94 2 28pm