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r s Tank Closure Report Quik Stop No. 121 Page 2 cutting the asphalt and concrete pad for removal. The two 10, 000- gallon and one 8, 000-gallon fiberglass fuel tanks were virtually empty when Wilkey' s started preparing the site for removal of the fuel tanks . A total of approximately 70 gallons of rinsate was collected from the three tanks and placed into 55-gallon drums . Prior to starting the excavation at the site, the City of Manteca expressed concern about the integrity of the pump island canopy. The footings which supported the canopy were extremely close to the east edge of the proposed excavation. Based on this information, the City of Manteca required the canopy footings to be reinforced prior to the start of excavation. Sheet piling was driven into the ground on the east side of the canopy and two steel I-beams were welded (one on each side of the canopy) to the support columns and to the sheet piling to provide added support. The excavation work began the afternoon of March 23, 1998, with the removal of the concrete pad and pea-gravel around the fuel tanks. The excavated pea-gravel was stockpiled on the southwest and west sides of the site and covered with plastic. The tank backfill material was excavated and the fuel tanks were exposed along approximately 3/4 of their sides and ends . The exposed portions of the tanks appeared to be in good condition, and the sidewalls of the excavation did not exhibit any signs of contamination. It should be noted that tank T-1 (Figure 2) was accidently punctured on the south end of the tank during the removal of the pea-gravel . The tank was patched with a resin compound. The tanks were completely empty at the time. On the morning of March 26, 1998 the remainder of the fuel tanks were exposed. At approximately 8 A.M. , the tanks were purged with 200 pounds of dry ice per tank. Mr. Robert McClellon of the County required 30 pounds of dry ice per 1, 000 gallons of tank capacity. At 10 : 30 A.M. , an additional 100 pounds of dry ice were added to each tank. San Joaquin County would not allow the tanks to be removed until the lower explosive limit (LEL) was measured at close to 5% LEL. At 11: 10 A.M. , Tank No. 1 (Figure 2) was measured at 5. 5% LEL and 1. 5 % oxygen level and was removed from the excavation and placed on a flat bed truck. At 11: 25 A.M. , Tank No. 2 was measured at 8% LEL and 2 . 4 % oxygen and removed from the excavation. At approximately 11: 45 A.M. , Tank No. 3 was measured at 7 % LEL and 3. 9 % oxygen level and was removed from the excavation. No apparent holes were observed in any of the three fiberglass tanks with the exception of the patched hole on Tank T-1 . All