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Site Characterization and Soil Rennediation Plan: 7500 West Eleventh Street, Tracv, C4. Page 4 Following is a summary of the information regarding the environmental condition of the subsurface generated when the tanks were removed from the property. The location of the pump islands, tank pits and pipeline routes are shown on Figure 3 The four registered underground tanks that were in use prior to the closing of the Olympian Service Station were removed from Tank Pit No. 1. They included one 10,000-gal. diesel tank, one 3,500-gal. diesel tank and two 8,000- gal. gasoline tanks. Following removal of the-registered tanks from Tank Pit No 1, operations were begun to remove their associated piping. That work revealed an unusually complex maze of piping centered beneath the former location of the pump islands, with branches extending to other locations on the property- When the rdremoval operation was complete, the total piping amounted to several thousand linear feet. Excavation of the piping also revealed that soil beneath the area around the former pump islands was affected by fuel hydrocarbons to a depth ' at least equal to that of the groundwater table. That soil was excavated and placed in a separate stockpile. For convenience of reference, the area from which that soil was excavated was designated the "Dispenser Pit." The locations of the Dispenser Pit and trenches from which piping was removed are shown on Figure 3. ";. After piping was removed from Pipe Trench No 1 (see Figure 3 for location), Dietz Irrigation recovered soil samples from along the length of that trench 1 -I During the course of that work, another underground storage tank was detected. Excavation around the area of that discovery revealed that there was, in fact, a total of four 1,000-gal, fuel storage tanks in that area, the presence of which was previously unknown. These very old (circa 1930) tanks were badly { deteriorated, thus, it was impractical to inert them prior to removal from the ground. Consequently, under the oversight of a representative of the SJCPHS, r they were lifted,from the ground, cut up and shipped off-site for disposal. Following the unexpected discovery of the four old tanks described above, a . search was performed by excavating near the ends of all the pipe trenches and at other suspect locations on the property for other unknown tanks that might be present on the site. None were found. However, that work and the extensive excavation necessary to remove the maze of pipelines revealed that there were at least three distinct layers of concrete and bituminous macadam paving and of other service station infrastructure laid down on the site at different times. It ' appears that, at successive times since a filling station was first operated on the property, older filling stations were demolished and overlain by the infrastructure and appurtenances of new facilities. sic