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Well Destruction Workplan TC Jamar Service Station Page 3 of 5 In a letter dated April 2, 2009, the SJCEHD stated that it believes that the C-zone monitoring wells should be installed to verify the reported concentrations of contamination from the CPT borings in the deeper zone before any additional CPT work is done. The SJCEHD also requested an additional C-zone monitoring well be installed in the northeast corner of the property, near the locations of CPT- 2/MW-1. The EHD did not approve installation of additional ozone infusion points in the C-zone until the new deep monitoring wells confirm contamination on site in that zone. Between November 22 and December 6, 2010, ATC supervised the installation additional C-zone monitoring wells MW11C to approximately 111 feet bgs, MW1C to approximately 110 feet bgs, MW3C to approximately 110 feet bgs. These wells were installed to further evaluate the vertical migration of the plume both on and off site. ATC supervised the installation of A-zone monitoring well MW12A to approximately 75 feet bgs to evaluate the extent of the plume in the northern part of the site.Additionally, ATC supervised the installation of ozone injection wells IW6 and IW7 to approximately 77 feet bgs. From January to April of 2011, ATC supervised modifications and expansion of the existing remediation compound and installation of a SVE system that included a Mako 250 thermal-catalytic oxidizer (TCAT) unit. The SVE system began operation in Fourth Quarter 2011. The SVE system generally ran continuously (approximately ten hours per day) through February 15, 2016 when the system was down for repairs. Due to difficulty with troubleshooting and noise complaint issues the thermal oxidizer was replaced with a fully enclosed catalytic oxidizer that is operated 24 hours a day. The new system was permitted with the San Joaquin Valley Air Pollution Control District and restarted on July 29, 2016. From January 3 to 9 and February 20 to 22, 2018, ATC field staff supervised the installation of one shallow and four deep off-site monitoring wells, MW13A MW13B, MW13C, MW14B and MW14C, and the advancement of three shallow on-site soil borings as described in ATC's Workplan for Additional Site Assessment Activities, dated May 26, 2017. Results from the shallow on-site borings showed that limited SVOCs were detected at very low concentrations in one shallow soil sample collected from the boring located at the former waste oil tank. No SVOCs were detected in the deeper soil sample collected from the same boring. Title 22 metals were detected in the samples collected from the soil boring near the former waste oil tank did not exceed California Human Health Environmental Screening Levels for the Commercial/Industrial scenario. ATC concluded that the shallow soil at the site and in the vicinity of the former waste oil tank has been adequately investigated. At the direction of the CRWQCB, the ozone sparging system was shut off on March 30, 2017. The system was modified to injection ambient air into the subsurface. In December 2018, ATC supervised the advancement of CPT-7 and an adjacent HydroPunch® boring off site to the east of monitoring wells MW14B and MW14C along the south side of Main Street. A groundwater sample was collected from the adjacent HydroPunch® boring at a depth of 145-150 feet bgs, and analyzed for TPHg, BTEX, and fuel oxygenates with 1,2-DCA and EDB. These constituents were not detected in the groundwater sample. In September 2019, the CRWQCB requested a proposal for additional downgradient assessment. Pursuant to the CRWQCB's request,ATC submitted the Workplan forAdditional Off-site Assessment Activities dated, November 11,2019.The workplan was approved by the RWQCB in correspondence dated December 30, 2019.