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Mr. Jeff Tierney, E.I.T. GeOSynteC D July 1, 2022 consultants Page 3 • A site-specific task hazard analysis (THA)will be created for the scope of work described in this Addendum. The THA will contain procedures for hazard identification and mitigation, emergency response, including a map of the nearest hospital and emergency contact information, incident reporting, use of appropriate personal protective equipment (PPE), and air monitoring procedures, if applicable. Prior to the start of field activities, a safety tailgate meeting will be conducted that will include a discussion of the field activities to be performed, safe work practices, identification of potential hazards, use of PPE, decontamination procedures, and emergency response protocols; and • The drilling location will be marked with white paint and Underground Services Alert (USA) will be contacted a minimum of 48 hours prior to commencement of intrusive subsurface activities. Additionally, a private utility locator will be contracted to perform a geophysical survey in the vicinity of the proposed boring location area to identify the presence or absence of potential utilities, pipelines, or other subsurface obstructions prior to drilling. The proposed boring location may be adjusted based on the results of the USA alert, the private geophysical survey, and the accessibility of locations with respect to obstructions on the property. Soil Vapor Probe Installation Geosyntec will contract a California-licensed C-57 drilling contractor to perform drilling activities using a hand auger at the location shown in Figure 3. A total of two SVPs will be installed as a nested set within a single borehole; a deeper SVP will be installed at 10 feet below ground surface (ft bgs) and a shallower SVP will be installed at approximately 5 ft bgs within the single borehole. These planned depths are consistent with the depths of the four on-site SVPs installed in October 2021, as described in the Work Plan. The proposed SVP construction details are shown in Figure 4. At the planned off-site SVP location, the existing asphalt or concrete surface will be cored to provide access to the underlying soil.The borehole will then be advanced using a 3.5-inch diameter hand auger to approximately 10 ft bgs. Soil cuttings from the borehole will be visually logged by Geosyntec field personnel under the direction of a California-licensed engineer or geologist for classification of soil type using the Unified Soil Classification System as guidance. Samples from the soil cuttings will be collected and placed in a sealed plastic bag and then allowed to equilibrate. The headspace of the soil cutting samples will be field screened for VOCs using a photoionization detector and recorded on field logs. Following boring advancement to the target depth, each of the two SVPs will be constructed in the borehole using a '/2-inch-diameter, 6-inch-long stainless-steel screen attached to '/4-inch diameter NylaflowTM tubing. One shallow SVP will be installed at approximately 5 ft bgs and a deeper SVP will be installed at 10 ft bgs within the single borehole. The exact depth of probe installation will depend on field conditions, geology encountered, depth to groundwater, and potential refusal by engineers I scientists I innovators