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Limited Site Investigation Irerracon Vacant Property ■Tracy, California November 13, 2020 ■Terracon Project No. NA197074 3.1 Geophysical Survey On November 26, 2019 Ground Penetrating Radar Services(GPRS)mobilized to the site to perform a geophysical survey of the areas associated with the investigation. GPRS utilized ground-penetrating radar (GPR) and magnetometer survey methods to perform the survey. The purpose of the survey was to attempt to determine the presence or absence of product pipelines and potential buried utilities in the vicinity of the proposed boring locations prior to subsurface exploration. The geophysical survey consisted of scanning the area of interest first with an electromagnetic(EM) instrument followed by a GPR scan to further evaluate any EM anomalies, if present. The geophysical survey was performed in the specific soil boring locations. Evidence of the pipelines were identified during the geophysical survey. No other utilities were identified during the survey. 3.2 Soil Sampling Sampling was performed in 16 discrete locations of the site, including from soil borings completed to various depths. Boring locations relative to site features are depicted on Exhibit 3 of Appendix A. The results of the soil samples collected are presented in Table 1 of Appendix B. A Terracon field representative mobilized to the site on November 26, 2019 to oversee the advancement of 4 soil borings; SB2, SB3, SB4 and SB5 from the historic pipeline rupture area and soil excavation. Due to heavy rainfall and site access issues the drilling was postponed until December 12 and 13, 2019, when soil borings SB1 and SB6 were completed in the pipeline ruptured area and soil excavation, and SB7 through SB16 were completed and sampled in the area of potential excavated soil stockpiles. On December 18, 2019, shallow soil samples from approximately 1 foot below ground surface (bgs)were collected at locations SB7, SB8, SB9 and S1310. The soil borings were advanced by Terracon, a California State-licensed driller, using a limited access and track-mounted hallow stem auger drill rig for borings SB1 through SB16. Throughout the drilling operation, soil samples were obtained continuously (to the extent practical)from 4-foot long core barrels advanced into the ground during the auger advancement. The steel split barrel sampler was extracted from the hole and opened to allow for field screening and sample collection of the soil. Non-disposable sampling equipment was cleaned using a non-phosphate soap wash and potable water rinse prior to the beginning of the project and before collecting each soil sample. Borings were advanced to total depth between 20 and 30 feet bgs for SB1 through SB8, and to 10 feet bgs for S139 through SB16. Groundwater was not encountered during the investigation. Responsive ■ Resourceful ■ Reliable 3