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April 14, 1995 Page 2 During tank removal, 1,100 cubic yards of soil were removed from the site Solls within the tank excavation were removed to a depth of 30 feet Soils at the base of the excava- tion contained a maximum of 18 parts per nullion (ppm)total petroleum hydrocarbons calculated as gasoline(TPH-g) and 1 7 ppm benzene Soils beneath the product lines were found to have a maximum TPH-g concentration of 6 ppm No benzene was detected in the product line samples No hydrocarbons were detected beneath the waste oil tank Kleinfelder, Inc installed five soil borings (KB 1 through KB5) at the site in Janu- ary 1988 These borings were installed around the former tank complex, adjacent to the product islands, and adjacent to the former waste oil tank (Figure 2) Between June 1988 and February 1992, AGS and RESNA, Industries installed a total of seven monitoring wells (MW-I through MW-7) and three SVE wells (VW-1 through VW-3) Monitoring Wells MW-1, MW-2, MW-3, and MW-6 are located on site and Wells MW-4, MW-5, and MW-7 are located northeast (downgradient) of the site The SVE wells are located in the vicinity of the former product islands RESNA/AGS-also installed I I soil borings (B-1 through B-11) Most of these borings were converted to either groundwater monitoring wells or SVE wells The monitoring well and SVE well locations are shown on Figure 2 A SVE test was performed in March 1992 by RESNA The results of flus test show that with a wellhead flow rate of 43 cubic feet per minute (cfm), an effective radius of influ- ence of approximately 25 feet can be achieved for one vapor extraction well These results were documented in a. report by RESNA dated January 4, 1993 In July 1994, PACIFIC installed two off-site monitoring wells (MW-8 and MW-9) The results of this investigation show that the lateral extent of dissolved hydrocarbons in groundwater is limited to an area south and east of the former underground storage tanks The extent of hydrocarbons has been defined to non-detectable levels to the northeast (downgradient) in Well MW-7, and to the north (crossgradient) in Wells MW-1 and MW-5 TPH-g was detected to the southwest (upgradient) in Well MW-8, and to the south (crossgradient) 1n Well MW-9, at concentrations of 93 and 110 parts per billion (ppb), respectively Benzene was not detected in Wells MW-8 and MW-9 All on- and off-site groundwater monitoring wells are currently being monitored and sampled on a quarterly schedule SOIL CONDITIONS The site is underlain by primarily fine-grained deposits consisting of interlayered clays and silts to an approximate depth of 50 feet Some surficial silty sands occur to a depth 3100403AIWORKPLAN