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Records Center UST Closure In-Place and Soil Sampling Report April 20,2012 Page-2- soil was impacted by TPH-G, and to a lesser extent, by toluene, ethyl benzene, and xylenes.. Metal analyses results were typical of background metals concentrations for this area of Stockton. Condor recommended that the UST be removed. Condor prepared the Underground Storage Tank Removal Work Plan dated January 11, 2012 and submitted the work plan to the City of Stockton Fire Department Fire Prevention Division(FPD)and the San Joaquin County Environmental Health Department(SJCEHD) for approval along with an application for an underground storage tank removal permit. The work plan and permit application were approved in a letter from SJCEHD dated February 29, 2012. The work plan approvals are included in Appendix B. Prior to implementation of the work plan is was determined that the close proximity of the tank to an active natural gas line, electrical line and the close proximity of the warehouse wall foundation would make full removal of the UST challenging. Condor recommended closure in-place in the Revised Underground Storage Tank Removal Work Plan dated March 20, 2012 and submitted the work plan to the SJCEHD for approval. 3.0 UNDERGROUND STORAGE TANK CLOSURE IN-PLACE On March 29, 2012,. Condor and Jim Thorpe Oil excavated and exposed one single-walled steel UST and associated product piping at the Site. The location of the UST, and product piping are shown in Figure 3, Appendix A. A Condor representative was on Site to make field observations and collect soil samples following the removal activities. Jeffery Wong of the SJCEHD and Tim Salladay of the City Of Stockton Fire Department Fire Prevention Division (FPD) were on Site to observe the UST closure activities and to specify soil sampling locations. The UST was exposed in an excavation in the southeast corner of the driveway entrance to the parking garage at the Site (Figure 3, Appen ix A). The UST excavation was approximately 8 feet by 7 feet and three to six feet deep. The native Soil observed in the excavation consisted of reddish brown, slightly moist, stiff, lean clay. Soil above and around the UST was observed to be poorly graded sand from the ground surface to approximately five feet bgs. The sand was also found in a conical pile inside the UST. The presence and location of the Sand indicated that the UST have been previously abandoned. No petroleum hydrocarbon staining of soil was observed in the sidewalls of the excavation. The top of the UST was two and a It if feet bgs, four feet in length, had a diameter of approximately four feet. The bottom of the tank appeare to be at six and a half feet bgs. The UST was a 375-gallon capacity, single-walled steel tank. Observatio of the exterior of the UST indicated that the UST appeared to be in good condition with no visible hol s or cracks. The piping that would have risen to the surface and dispenser had been removed and the pipe plugged with a metal fitting. The vent piping had been left connected and in place. The fill piping had been removed and left open. The UST had obvious rust corrosion, but was sound when struck with a hammer to remove loose soil and rust prior to painting the tank number on the side with orange paint. The tank was numbered 39-0520449 as specified by SJCEHD. 4.0 SOIL SAMPLING Prior to abandonment of the UST, soil samples were collected from locations selected by the SJCEHD and Condor. A hand-auger was used to excavate an angled access hole from near the side of the UST to below the UST. Soil samples 5960 -W-8 and 596013-E-8 were collected from the western and eastern end of the UST, respectively, at a depth of approximately eight feet bgs, or approximately one and half feet below the UST. The hand Auger was then used to advance the boring approximately two feet deeper. Soil samples 596013-W-10 and 5960B-E-10 were collected from the western and eastern ends of the UST, n �(� COND(