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Subsurface Investigation Scope Prior to commencement of subsurface investigation activities, public utility locate services would be notified so that underground utilities can be located prior to the start of work. At the time of the site investigation, prior to the start of work, an on-site health and safety plan will be completed and signed by the on-site consultant and drillers (attached to this work plan). The proposed subsurface investigation would include advancing up to three sub-slab soil vapor samples in areas about the spray-paint booths and paint mixing area; and at least one boring adjacent to the clarifier near the southeastern corner of the northern shop building. The geoprobe boring would be advanced to depths of up to approximately 20 feet below ground surface (bgs) depending on the location on the property and depth to groundwater. Continuous soil sampling would be performed on at the boring, the soils identified and logged, and the soil cores reviewed for indications of contamination. At least one soil sample would be collected from each boring within areas of suspected impact or, if no indications of impact were observed, at a shallow point in the boring as well as at the deepest portion of the boring. If groundwater is encountered during drilling activities, a temporary screen will be set and a well-point groundwater sample will be obtained. Sub-slab soil vapor samples would be analyzed for volatile organic compounds (VOCs) that may have migrated into sub-slab areas as a result of spray-paint booth operations and related automobile painting activities. Soil samples and/or groundwater samples would be analyzed for the potential presence of VOCs, specifically chlorinated and oxygenated solvents associated with automobile painting activities. The Environmental Protection Agency analytical methods that may be used in this investigation are included as Attachment 1. A site plan with the approximate locations of the proposed borings is shown in Attachment 2. Boring locations may be modified based on site conditions and/or locations of existing utilities. A summary report of the investigation and analytical results would be prepared upon the completion of the field activities and receipt of the laboratory analytical report. Investigation Methods Sub-slab vapor sampling and direct push activities would be performed by TEG-Northern California, a California licensed driller—License Number C-57 706568, using a direct push drilling rig. Sub-slab soil vapor sampling would be performed using a roto-hammer drill, Teflon tubing, and individually cleaned and certified Summa® canisters with individual flow controllers and pressure gauges. Soil sampling would be accomplished using a two-inch diameter, four- or five-foot long, hollow stainless steel sampling tube lined with acetate sample liners advanced on stainless steel push rods. Each boring would be backfilled and cemented with a cement grout mixture consisting of approximately 95% Portland Cement and 5%Bentonite with the surface restored using a concrete or asphalt patch. All non-disposable sampling equipment would be steam cleaned or power washed in between each boring and at the end of the sampling event. Soil spoils and cuttings as well as decontamination water would be collected and stored in a separate lidded bucket or 55-gallon drum, depending on the amount of material, and the container labeled with a"non-classified waste material' label containing information on material, site name and address, generation date, and generator and contractor contact information. A copy of this label is attached to this work plan. Waste soil and decontamination water would remain on the site until receipt of the laboratory analyses when the appropriate disposal method, such as landfill, etc., can be determined. Sample Collection Methods Sub-slab vapor samples will be collected in certified Summa® canisters with individual flow controllers and pressure gauges along with soil and/or groundwater samples collected in new, specially cleaned Work Plan for Limited Subsurface Environmental Sampling 7710 Murray Drive 2 t�UCh,,,. Tracy, California 95376 —