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Rutan & Tucker, LLP 13 July 2023 Page 2 Figure 1 shows the locations of the above -referenced properties, including the locations from which methane samples were collected. Methane Concentrations The following summarizes the methane concentrations detected at each of the above -referenced properties. 4707 CORRAL HOLLOW ROAD, AKA CITY OF TRACY LANDFILL In May 2020, Haley & Aldrich installed and sampled four temporary soil vapor probes located on this property. The objective of this sampling was to assess the soil vapor conditions, including methane, in the vicinity of buried waste material that was associated with the City of Tracy Landfill that historically operated on this property through December 1946. Three of the soil vapor probes, 707 -SV -01, 707 -SV -02, and 707 -SV -04, were situated within areas with identified buried waste, and the fourth probe, 707 -SV -03, was located north of the buried waste to assess potential vapor migration away from this area. The collected soil vapor samples were analyzed for fixed gases (oxygen, carbon dioxide, and methane) using American Society for Testing and Materials (ASTM) Method 1946D. These activities were performed in general accordance with the California Department of Toxic Substances Control (DTSC) Advisory Active Soil Gas Investigations (Soil Gas Advisory), dated July 2015. Low concentrations of methane were generally detected, except at location 707 -SV -04 where methane was detected at 2.3 percent, which is above the California Code of Regulations Title 27 (27 CCR) explosive gas control compliance level of 1.25 percent (27 CCR Section 20921.5). Probe SV -04 was located in an area where a geophysical survey identified a strong signal for buried waste and where waste was encountered during a pothole investigation. Methane concentrations detected in the other three probes ranged from less than 0.00027 percent to 0.032 percent. 30600 CORRAL. HOLLOW ROAD, AKA KT PROPERTY, AKA HILLVIEW In August and September 2021, Haley & Aldrich installed and sampled two temporary soil vapor probes located on the southwest corner of the property, 600 -SV -01 and 600 -SV -02. The objective of this sampling was to evaluate potential soil vapor impacts, including methane, related to the nearby Phillips 66 underground petroleum pipeline to comply with Mitigation Measure (MM) 4.$-2a of the Draft Environmental Impact Report (DEIR) prepared for the Tracy Hills Project. Collected soil vapor was measured for methane concentrations using a calibrated field meter. These activities were performed in general accordance with the DTSC Soil Gas Advisory. Methane was not detected in the soil vapor collected from either probe. TRACY HILLS PHASES 2, 3, AND 4 In January 2022, Haley & Aldrich installed and sampled 12 temporary soil vapor probes located on this property, TRH -SV -01 through TRH -SV -12. The objective of this sampling was to evaluate potential soil vapor impacts, including methane, related to the nearby Shell Oil underground petroleum pipeline to ALDRICH