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Limited Phase II Subsurface Investigation Work Plan 1319 & 1327 South Madison Street Stockton, California 95206 Finally, the immediately adjoining/upgradient property at 163 French Camp Turnpike (to the northeast, beyond road, approximately 50 feet) is listed as, Aalhini & Stefani Gas and Aalimbini & Baroni (Gasoline and Oil Service Stations) in 1940 and 1946. This property may pose a threat for vapor phase contaminant migration to the Site and AEI recommends further investigation to assess whether a vapor phase migration concern exists at the Site. The purpose of this investigation is to assess the presence/absence of impacted subsurface conditions (i.e., soil and soil gas) ) at the Site relative to the identified RECs. 3.0 Geology and Hydrogeology Geologically, the Site is underlain by the Pleistocene Modesto Formation which consists of unconsolidated, unweathered gravel, sand, silt, and clay. As described in the Phase I ESA, the depth to groundwater is estimated at 16 to 30 feet below ground surface (bgs) and the direction of groundwater flow is estimated to the southwest based on the general topographic interpretation. 4.0 Scope of Work AEI was requested to perform an investigation, including the collection of soil and soil gas samples, to assess if the identified RECs have adversely impacted the Site. 4.1 Health and Safety, Permitting, and Utility Clearance A site-specific health and safety plan will be prepared, reviewed by onsite personnel, and kept onsite for the duration of the fieldwork. Drilling permits will be obtained from San Joaquin County Department of Environmental Health for this investigation.The public underground utility locating service Underground Service Alert (USA) North 811 will be notified to identify public utilities in the work area. AEI will arrange for a private utility locating service to check planned drilling locations for possible utilities. 4.2 Drilling and Soil Sample Collection AEI will contract a licensed driller to advance five exploratory soil borings at the Site with a truck- mounted, direct push drilling rig. One (1) boring adjacent to the inground lift will be advanced to a maximum depth of 10 feet bgs. The remaining borings will be advanced to a maximum depth of 5.5 feet bgs. The tentative locations of the proposed borings are shown on the attached figure and include the following: • One (1) boring will be placed near the inground lift, • One (1) boring will be placed in the unpaved area north of the Site building near the waste drums, • One (1) boring will be placed in the landscape/unpaved area west of the Site building; and • Two (2) borings will be placed along the northeast property boundary, downgradient of the offsite former gas station.