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Underground Storage Tank and Product Line Replacement Report-Tosco 76 Branded Facility No. 11195 Aprit 23, 1999 Former Product Line Overexcavation Sampling On December 31, 1999, at the request of Mr. Infurna, overexcavation was initiated around the product line location represented by soil sample TL-1-2.5 (north end of the west dispenser island). The limits of the completed excavation measured approximately 13 feet by 13 feet by 11.5 feet deep (Figure 4). Confirmation soil samples TL-4-7.5, TL-5-11, TL-6-8, and TL-7-6 were collected from the sidewalls of the excavation at depths of 6 to 11 feet bgs. Confirmation soil sample TL-1-10.5 was collected from the bottom of the excavation at 10.5 feet bgs. These samples were analyzed for TPHg, BTEX, MtBE, six oxygenate compounds, and total lead. Samples TL-4-7.5 and TL-7-6 were reported as not detected for all analytes except for 1.9 and 2.8 ppm of total Iead, respectively. The remaining samples were reported as not detected for benzene, MtBE, six oxygenate compounds, and contained 120 to 950 ppm of gasoline and unidentified hydrocarbons, and 2.7 to 3.8 ppm of total lead. Soil Stockpile Sampling Soil generated during UST and product line removal and related overexcavation and current gasoline LIST complex excavation activities was stockpiled and sampled to determine reuse or disposal options. Approximately 125 cubic yards of pea gravel was removed from the former gasoline UST excavation prior to UST removal and stockpiled on-site. Stockpile samples SRI r through SP-5 were collected from the stockpile and analyzed for TPHg, BTEX, MtBE, six nr oxygenate compounds, and total lead. The samples were reported as not detected for TPHg, benzene, MtBE, and total lead, except for 1.3 ppm of TPHg in SP-3 and 0.054 ppm of MtBE in SP-2. The laboratory inadvertently failed to analyze the samples for oxygenate compounds. The 125 cubic yards of pea gravel represented by sample SP-1 through SP-5 was used to backfill the former gasoline UST excavation. Approximately 200 cubic yards of soil and pea gravel were removed from the former gasoline UST excavation and stockpiled on-site after removal of the USTs. Composite stockpile samples SP-6A-D and SP-7A-D were collected from the stockpile and analyzed for TPHg, BTEX, MtBE, six oxygenate compounds, and total lead. Upon receipt of the analytical data, the material was profiled and transported Forward Landfill in Stockton, California. Approximately 50 cubic yards of near-surface native soil was excavated from the new gasoline UST complex and used by Walton to backfill the former product line over-excavation. Samples SP-8 and SP-9 were collected from the soil and analyzed for TPHg, BTEX, MtBE, six oxygenate compounds, and total lead. The samples were reported as not detected for all analytes except for 0.12 ppm of MtBE and 6.7 ppm of total lead in SP-8 and 2.5 ppm of unidentified hydrocarbons greater than C8 in the range of TPHg, 0.0064 ppm of xylenes, and 4.1 ppm of total lead in SP- 9. 140193.03 _:� 4