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Mr . Muniappa Naidu Page 2 Initial Soil Sampling In order to determine if the UST leaked and caused a condition of soil contamination on August 8 , 2019 Ground Zero drilled and sampled two soil borings at the locations shown on Figure 2 . Field Work According to the records in the EHD file, the UST invert was at a depth of six (6 ) feet below grade . Consequently, on August 8 , 2019 two borings were advanced with a hand auger, one at each end of the former UST , and native soil samples collected at a depth of approximately nine (9) feet below ground surface (bgs ) . The samples were obtained using a drive sampling device containing clean stainless-steel sampling sleeves . The sleeves were sealed with Teflon film, capped, uniquely identified and placed in a chilled ice chest pending delivery to the laboratory under chain- of-custody protocol . Upon completion the borings were backfilled with neat cement grout and the concrete pavement surface was restored . Backfilling was witnessed by Mr. Jeff Wong of EHD . Laboratory Analysis The samples were submitted to State-certified BC Laboratories (ELAP No . 1186) where they were analyzed for total petroleum hydrocarbons as gasoline (TPHg) by LUFT-GC/MS ; for volatile organic compounds (VOCs) including benzene , toluene , ethylbenzene xylenes (BTEX) , naphthalene , gasoline oxygenate additives and lead scavengers (MTBE, TBA, TAME, ETBE, DIPE , 1 ,2-DCA and EDB ) by EPA Method 8260 ; and for total lead by EPA Method 6010 . Analytical Results The laboratory analytical results are summarized in Table 1 . In boring HAB 19 -01 -9 ' , which was located at the north end of the former UST excavation , TPHg was detected at a trace level of 0 . 56 parts per million (ppm) and lead was detected at a concentration of 5 . 1 ppm. No VOCs were detected. In boring HAB 19-02-9 ' , which was located at the south end of the former UST excavation, TPHg was detected at a very low level of 10 ppm and lead was reported at 17 ppm. Of the VOCs , only trace levels of naphthalene (0 . 0023 ppm) , 1 ,2 ,4-trimethylbenzene (0 . 0073 ppm) , 1 , 3 , 5 - trimethylbenzene (0 . 0058 ppm) and xylenes (0 . 0085 ppm) were detected . Reporting The results were transmitted to EHD in the letter report titled Results of Soil Sampling for Underground Storage Tank Closure dated August 27 , 2019 . Ground Zero concluded that the soil sampling beneath the location of the former UST detected only de -minimus concentrations of gasoline and certain gasoline component compounds which was not indicative of a significant fuel leak. We recommended that San Joaquin County EHD consider the UST to have been properly closed. EHD consulted with Mr . Alan Buehler of the Regional Water Quality Control Board (RWQCB ) . Mr . Buehler recommended that additional soil and groundwater samples be collected before a decision was made whether or not to open a leaking underground storage tank case . Additional UST Soil and GW Sampling Report