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! %.W C A M B R I A the tank removal are presented in Delta Environmental Consultants, Inc.'s (Delta's)April 6, 1989 Tank Closure Report. 1989 Site Investigation: During August 1989, Delta drilled six soil borings and converted three of the borings to groundwater monitoring wells (MW-1 through MW-3). The three well borings and the two soil borings drilled near the northwestern (SB-1) and southern dispensers did not contain detectable concentrations of TPHg or benzene. The soil boring drilled in the former UST excavation contained maximum concentrations of 0.3 ppm TPHg and 0.005 ppm benzene. Soil data for boring SB-1 are included in Table 1 and the boring location is shown on Figure 2. Investigation results are documented in Delta's October 20, 1989 Phase I Hydrogeologic Assessment Report. 1990 Problem Assessment Report: In October 1990, Delta submitted a Problem Assessment Report requesting case closure. 1997 Site Investigation: During December 1997, Cambria drilled two soil borings near the northwestern dispenser(B-1 and B-2). Soil samples from B-1 contained TPHg concentrations up to 2,100 ppm and benzene up to 0.57 ppm,with the highest concentrations at 17 feet below grade (fbg). Soil samples from boring B-2 did not contain detectable concentrations of TPHg or benzene, and neither boring contained detectable concentrations of fuel oxygenates. Water was encountered in boring B-1 at approximately 14.7 fbg. Because depth to groundwater beneath the site historically ranges from approximately 29 to 60 fbg, the water observed in boring B-1 is most likely perched. A grab water sample from this perched zone contained 110,000 parts per billion (ppb) TPHg and 260 ppb benzene. Fuel oxygenates were not detected in this water sample. Soil and groundwater data from this investigation are included in Tables 1 and 2, respectively,and the boring locations are shown on Figure 2. The investigation is summarized in Cambria's March 10, 1998 Site Investigation Report. 1998 Upgrade Activities: During March 1998, Cambria inspected the site during fuel and waste oil UST overspill upgrade activities. No soil samples were collected. Cambria submitted a 98 Upgrade Site Inspection Report on October 15, 1998. Groundwater Monitoring Program: There are currently three monitoring wells onsite (MW-1 through MW-3)that are sampled quarterly. During the first quarter 2002 sampling event, methyl tertiary butyl ether (MTBE) was detected in well MW-1 at 9.5 ppb. MTBE was not detected in wells MW-1 or MW-2. Groundwater samples from wells MW-1 through MW-3 did not contain detectable concentrations of TPHg,benzene,toluene,ethylbenzene,or xylenes (BTEX). 0832 2