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Broadbent&Associates,Inc. Vacaville,California Site Assessment Work Plan Former ARCO Station No.443 November 8,2013 Page No.In A review of the historical data does not indicate that integrity of MW-8 has been compromised and there is no evidence of vertical migration of contaminants in this well. Based on this information, Broadbent believes that decommissioning and replacing MW-8 with another monitoring well would not add any value to the future sampling and monitoring results at the Site. Broadbent also recommends that MW-8 be left as a data point and should be continued to be sampled on a semi-annual basis. 3.0 PROPOSED SCOPE OF WORK A brief description of the proposed activities is presented below: • Perform a ground penetrating radar(GPR)survey to verify that no underground storage tanks are present at the Site; • Mark the locations of underground utilities in areas where soil gas wells will be installed and soil borings will be advanced; • Install two temporary soil gas wells adjacent to the onsite building; • Purge and sample the soil gas wells after conducting shut in and helium leak tests; • Using hand auger, collect soil samples at depths between 0 and 5 feet and 5 and 10 feet bgs at two select locations on the Site;and • Analyze soil and soil gas samples for the presence of gasoline range organics (GRO), benzene, toluene,ethyl benzene,xylenes, and 1, 2 dichloroethane. 3.1 Preliminary Activities, Permitting,and Notifications Prior to the start of field activities, Broadbent will obtain necessary permits from SJCEHD. In addition, Broadbent will prepare a Site Health and Safety Plan (HASP)for the proposed work,clear the Site for subsurface utilities, and provide a minimum 24 hour advance notification to SJCEHD prior to start of field activities. GPR and electromagnetic line locating methods will be used to survey the accessible exterior and interior portions of the Site to detect potential presence of former USTs. The results of GPR survey will assist in closing the data gap regarding the removal of former USTs. The utility clearance will include notifying Underground Service Alert(USA)of the pending work a minimum of 48 hours prior to initiating the field investigation and securing the services of a private utility locating company to confirm the absence of underground utilities at the proposed well location. Once identified,the location and type of utility will be marked on the asphalt surface with spray paint. The Site-specific HASP will be prepared for use by personnel implementing the work plan.A copy of the HASP will be available onsite during work. The subcontractor(s) performing field activities will be provided with a copy of the HASP prior to initiating the work.Safety tailgate meetings will also be conducted to review potential hazards and scope of work.