CORRESPONDENCE_AGENCY CORRESPONDENCE

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Chevron - 2 - 12 March 2026 Surland Homes Tracy, San Joaquin County Work Plan Summary Prior to commencing field work, Arcadis will prepare a health and safety plan, obtain boring permits from San Joaquin County, notify Underground Service Alert, and retain a private utility locator to identify underground utilities. An access agreement will be made with the property owner at 2532 Dorset Lane. The property owner and Staff will be notified at least 14 days prior to starting field activities. A hand auger will be advanced to a depth of approximately 8 feet below ground surface (bgs). The soil boring will be logged to total depth using the Unified Soil Classification System, with PID readings to be collected at regular intervals until total depth. All work will be performed under the supervision of a California Professional Geologist. All down-hole equipment will be triple- rinsed with Alconox® or a similar solution prior to reuse. Soil samples will be collected using a slide hammer, with a maximum of two soil samples collected at depths of approximately 2.5, 5, and 8 feet bgs. One duplicate sample will be collected for quality assurance and quality control purposes. The soil samples will be analyzed by an accredited State of California laboratory for TPHg, TPH as diesel, TPH as motor oil, polynuclear aromatic hydrocarbons, and volatile organic compounds (VOCs). One dual-nested soil vapor probe will be installed in the boring with 6-inch screened in.tenials placed at approximate depths of 4.5 to 5 feet bgs, and 7.5 to 8.0 feet bgs. Each soil vapor probe will be completed with sand filter pack across the screened interval, one foot of dry bentonite above the sand and neat cement to the surface with sample tubing. Each screen will be set in a 1.5-foot interval of sand with approximately 6 inches of sand above and below the screen. A 1-foot interval of dry, granular bentonite will be placed above the sand pack. Neat cement will be placed above the shallow interval of hydrated bentonite to a depth near ground surface. The surface will be completed with a 6-inch diameter flush-mount well box. The soil vapor probes will be purged, and vapor samples collected at least 48 hours after vapor probe installation. A shut-in test will be performed prior to purging and sampling to check for leaks in the sampling train. Leak testing will be performed to evaluate the integrity of each sample and to confirm that significant ambient air is not in the soil vapor sample. The vapor probes will be purged by removing a minimum of three volumes of air from the sampling train, well tubing, and sand pack to ensure samples are representative of subsurface conditions. Soil vapor samples will be collected using laboratory-supplied, batch -certified, 1- liter canisters and flow controllers set to approximately 200 milliliters- per-minute. An equipment blank and a duplicate sample will be collected for quality assurance purposes. Vapor samples will be transported under chain-of-custody protocols to an accredited State of California analytical laboratory. Samples will be analyzed for TPHg, VOCs including naphthalene, helium, nitrogen, oxygen, methane, and carbon dioxide. Investigation-derived waste generated during this project will be stored in 55-gallon drums. The waste will be temporarily stored onsite and after profiling will be transported to an appropriate facility for disposal. A report will be prepared to include a description of the Site conditions, a scaled Site plan showing the boring location and other relevant Site features, documentation of field activities, a summary of the analytical results, and recommendations for the Site. If soil vapor concentrations at SV-1 have attenuated since B-13 was last sampled in 2020 and