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r <br />C <br />r_ <br />i <br />i <br />i <br />rij <br />C <br />C <br />u <br />0 <br />Ci <br />Mr. Michael Walton <br />Walton Engineering, Inc. <br />� d:�►ii�� Unca <br />October 16, 2003 <br />The former underground waste oil storage tank at the site was unearthed and removed by Walton <br />Engineering, Inc., on September 11 and 12, 2003, respectively. Prior to the removal of the <br />underground storage tank, the tank was rinsed and then evacuated by Ramos Environmental of West <br />Sacramento, California. Approximately 100 pounds of dry ice was placed in the 550 -gallon capacity, <br />waste oil storage tank. The dry ice reduced the lower explosive limit (LEL) and displaced oxygen <br />(02) to less than I% in the tank, prior to removing the tank from the subsurface. <br />Following the removal of the underground storage tank, the tank was inspected and found to be in <br />good condition with no apparent perforations. The tank was hauled from the site and disposed of by <br />Ecology Control Industries of Richmond, California. A representative from the local Fire Department <br />was present to supervise the tank removal operation. <br />FUEL DISPENSER REMOVAL <br />Five fuel dispensers and the connecting underground product lines were dismantled and removed <br />from the fueling station by Walton Engineering (FDI thru FD5 on Figure 2). The product line fiber - <br />trench exposed by the fuel system renovation work contained mainly pea gravel as a backfill material. <br />Soil encountered beneath the fuel dispensers consisted of a clayey sand, whereas soil encountered <br />beneath the trench backfill material consisted of a stiff, medium brown, silty clay. An odor of fuel <br />hydrocarbon was detected only beneath the product line trench near the northern ends of the fuel <br />storage tanks (PLI on Figure 2). Soil material observed beneath the former fuel dispensers and <br />beneath the former product lines at locations PL2 thru PL4 did not exhibit evidence for fuel <br />hydrocarbon contamination. <br />Following the removal of the underground waste oil storage tank, a soil sample was collected from <br />beneath the fill end of the tank at approximately 7 feet below ground surface using a hand -operated <br />AMS percussion core sampler containing a stainless steel sample sleeve. The sample was collected <br />from the bucket of a backhoe immediately after removing the soil from the base of the tank <br />excavation. Following the removal of the five fuel dispensers and associated underground product <br />lines at the site, a soil sample was collected from beneath each former fuel dispenser and product line <br />location using the core sampler. Immediately prior to each sample collection event, approximately <br />1 to 2 feet of soil material was removed from each sample location to expose fresh soil material at <br />a depth of approximately 3 to 4 feet below ground surface. Each soil sample was collected by driving <br />a clean sample sleeve through the freshly exposed soil surface using the percussion core sampler. <br />Immediately after collecting each soil sample, the filled sample sleeve was sealed with plastic end <br />caps, labeled with the project and sample identification numbers and date, and placed in iced storage. <br />' Additionally, a soil sample composite was collected from the soil stockpile generated during the tank <br />removal work (SP Ia-d on Figure 2). The sample composite consisted of four discreet soil samples <br />collected from the stockpile at random locations. Each discreet sample was collected after removing <br />GRAYLAND ENVIRONMENTAL <br />Graytand 022-370.fdr 2 <br />