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----------------- Underground Storage Tank and Product Line Replacement Report-Tosco 76 Branded Facility No. 11195 April 23, 1999 County Environmental Health Division (SJCEHD). The USTs and related product lines were removed on December 30, 1998. Upon removal, the USTs and product piping were visually inspected for evidence of failure. The USTs and product piping were found to be in good condition with no holes, cracks, or signs of leaks. In addition, single-wall fiberglass product lines related to a former station configuration were also removed. The USTs were removed from the site and transported by Ecology Control Industries to their Richmond, California facility for disposal. The UST disposal certificates are attached. The former UST excavation was approximately 30 feet by 40 feet by 12 feet deep. The new UST excavation is 30 feet by 30 feet by 17 feet deep and is adjacent to the former UST excavation. Excavation limits are shown on Figures 3 and 4. Groundwater was encountered in the formerand new UST excavations at approximately 11 to 12 feet below ground surface (bgs). A total of twenty-seven native soil samples, twenty-one soil stockpile samples, and two groundwater samples were collected and transported to Sequoia Analytical (Sequoia), in Walnut Creek, California (FLAP #1271), for chemical analyses. Analytical methods and results are summarized in Tables 1 and 2. Sample locations are shown on Figures 3 and 4. Copies of the laboratory reports are attached. Former Gasoline UST Excavation Soil Sam lin On December 31, 1998, eight soil samples (TX-1-11 through TX-8-11.5) were collected from the sidewalls of the former UST excavation within the observed capillary fringe at depths of approximately 11 to 12 feet his. In addition, one soil sample (N-1-16) was collected from saturated native material beneath the north UST at 16 feet bgs. Sample locations are shown on Figure 3. These samples were analyzed for Total Petroleum Hydrocarbons as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes (BTEX), and methyl t-butyl ether (MtBE) according to EPA Method 8015 (Modified)/8020, six oxygenate compounds according to EPA Method 8260, and total lead according to EPA Method 6010. Sample N-1-16 contained 1,500 parts per million (ppm) of TPHg, 47 ppm of MtBE, 290.0 ppm of ethanol, 19.0 ppm of tertiary butyl alcohol (TBA), and was reported as not detected for benzene, di-isopropyl ether (RIPE), and ethyl t-butyl ether (EtBE), tert-amyl methyl ether (TAME), and total lead. The analytical data results for the sidewall samples ranged from not detected to 130 ppm of TPHg, not detected for benzene, 6.8 to 50 ppm of MtBE, not detected to 51.0 ppm of TBA, not detected to 3.4 ppm of total lead, and not detected for ethanol, DIPE, ELBE, and TAME. Former Gasoline UST Excavation Groundwater Sampling Two groundwater grab samples were collected from the former UST excavation on December 30, 1998 (Figure 3). Groundwater grab sample SW was collected from groundwater within the indentation left in the bottom of the excavation after the removal of the south UST, 140193.03 _. 2