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SECTION 3 PREVIOUS INVESTIGATIONS ' This section discusses the investigation and closure activities previously conducted for Tank Sites 1, 2 and 3 While evidence of a possible release was found at both Sites 1 and 2, Site 3 showed no ' apparent impacts The individual sites are discussed separately below Tank Site #1 A 2,000-gallon underground fuel storage tank was removed in November 1988 from Former Tank Site #1, located at 1515 West Weber Avenue Analyses of soil and ground water samples collected from the tank excavation after removal activities indicated that a release of gasoline and gasoline components had occurred Soil and ground water investigations at Tank Site #1 were performed by Kleinfelder, Inc in March 1990 and by ERM-West in March 1991 Kleinfelder, Inc , conducted a soil gas survey, and installed three shallow borings and three monitoring wells (MW-1 through MW-3, Figure 3-1) ERM-West subsequently installed two additional monitoring wells These wells were located within and hydraulically downgradient of the tank site (MW-4 and MW-5, Figure 3-1) Investigation Findings The information collected during the construction of monitoring wells and soil borings indicate that the site is underlain by clays and sands ' Figure 3-2 presents a cross section of the former tank location at Site #1 Semi-consolidated clayey soils extend from the ground surface to a depth of approximately 8 to 10 feet bgs Below the clays, unconsolidated, fine-to-coarse-grained sands extend to a depth of at least 30 feet bgs ' Depicted on the cross section is an area of fill soils associated with the former tank Apparently, the petroleum-affected soils around the tank were excavated and removed from the site at the time the tank was removed The fill material consists of clayey soils similar to the surrounding native clayey soils 3-1 1