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associated piping. The top and bottom of the tank were approximately 3 and 8 feet below ground surface, respectively. The concrete fuel pump island was located immediately to the south of the fuel tank. The tank was installed approximately 25 years ago. In recent years, the tank has been used to store unleaded gasoline. It is likely that leaded gasoline was previously stored in the tank. On October 2, 1986, a tank-only precision test was performed on the fuel tank. The tank failed the test, and was emptied on October 3, 1986. On November 14, 1986, PG&E's Department of Engineering Research conducted a limited tank leakage study in the immediate vicinity of the former tank location in conjunction with PG&E's plan to close the tank. The purpose of this study was to determine whether gasoline hydrocarbons were present in the adjacent soil and groundwater. The scope of the investigation included drilling two test borings approximately five feet to the north and east of ' the former tank (Bl and B2, Figure 3) to depths of 13.5 and 15.5 feet, and collecting soil and water samples from the borings for chemical analysis. The depth to groundwater at the time of that investigation was estimated at approximately 8 to 9 feet. During the course of the November field work, hydrocarbon odors were detected in the subsurface soils obtained from boring B-1, and floating product was observed on the standing water in both borings. Selected soil and water samples collected from borings B-1 and B-2 were submitted to a State-certified laboratory (Clayton Environmental Consultants, Inc. ) for analysis of total petroleum hydrocarbons as gasoline (TPH)(EPA Method 8015) ; benzene, toluene, ethylbenzene and xylenes (BTEX) (EPA Method 8020/602) ; ethylene dibromide (EPA Method 8010/601) and lead (Method 239.2) . Results of these laboratory analyses, summarized in Tables 1 and 2 � Y indicated that elevated levels of TPH existed in free product form at both 3286a/BAV100 4 r