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CAMBRIA gallon double walled fiberglass underground gasoline storage tanks (USTs), one waste oil UST, a former UST complex, two dispenser islands, and a station building (Figure 2) 1987 Waste Oil Tank Removal- During June 1987, a 550-gallon steel waste oil UST located at the northern end of the service station building was removed Three soil samples were collected from the waste oil UST excavation in June, July, and August 1987 One of these samples contained 8,230 parts per million (ppm) total petroleum hydrocarbons as motor oil (TPHmo), 298 ppm total petroleum hydrocarbons as gasoline (TPHg), and 0 044 ppm benzene The other two samples did not contain detectable concentrations of TPHmo, TPHg, or benzene Total petroleum hydrocarbons as diesel (TPHd) were not detected in any soil samples from the waste oil UST There is not a report summarizing these activities in SJCEHD's files This information was obtained from field notes and laboratory analytical results, and precise sampling locations are not available 1989 Pre-Tank Replacement Site Assessment During October 1989, Aegis Environmental Consultants (Aegis) of Roseville, California conducted a pre-tank replacement subsurface investigation They dnlled 12 soil bonngs(B-1 through B-12)to assess subsurface conditions of soil in the vicinity of the existing underground storage tank(UST)pit and the new UST location The soil borings were drilled to 21 5 feet below grade (fbg) Groundwater was not encountered in any of the borings TPHmo,TPHd,and TPHg were not detected in any soil samples from the borings Benzene was detected at 0 07 ppm at 20 fbg in boring B-4 This investigation is summarized in Aegis' November 15, 1989 Pre-Tank Replacement Site Assessment Results Report 1990 Tank Removal- During May 1990, two 5,000-gallon USTs, one 7,500-gallon UST, and one 10,000-gallon UST were removed from the site and replaced with three 12,000-gallon double walled fiberglass USTs, installed in a different location Soil samples collected during the tank removal indicated that soil beneath the former USTs had been impacted by petroleum hydrocarbons TPHg and benzene were detected at concentrations up to 4,300 and 10 ppm, respectively The highest concentrations were detected m sample T2-S Samples collected from beneath the western and eastern dispensers contained 6 7 and 58 ppm TPHg, respectively Benzene was not detected in either dispenser sample These activities are documented in Aegis' June 14, 1990 Tank Closure Results Report 1990 Monitoring Well Installation: During July 1990, Aegis installed three groundwater monitoring wells(MW-1 through MW-3)and two vapor extraction wells(VEW-1 and VEW-2) TPHg was only detected in one soil sample collected from boring VEW-1 at 10 fbg at a concentration of 1 2 ppm • Benzene was detected in three of the soil samples (from borings MW-2, VEW-1, and VEW-2) at 0837 2