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stw1tK Well Destruction Work Plan ARCO Service Station No. 2186 February 7, 2012 extraction system during the second quarter 2008 indicated CDCs below the laboratory MRLs, which suggests that COCs are not suspected from five remediation wells VW-1A, VW-2A, VW-3A, VW-4, and AW-1. Based on this, Stantec also proposes to destroy these vapor extraction wells via pressure-grouting. The most recent groundwater analyses from two wells MW-IR and MW-11D indicated benzene or 1,2-dichloroethane above the laboratory MRL and MCL. Based on this, Stantec proposes to 2 destroy wells MW-1 R and MW-1 D via over-drilling. Table 1 summarizes the well construction details. Appendix B includes the boring logs. The following describes in detail the proposed scope of work. Site-Specific Health and Safety Plan As required by the Occupational Safety and Health Administration (OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (29 CFR 1910.120) and by California OSHA (Cal-OSHA) "Hazardous Waste Operations and Emergency Response" guidelines (CCR Title 8, Section 5192), the contractor will prepare a site-specific Health and Safety Plan (HASP). At a minimum, the HASP will define the proposed subsurface investigation activities, describe physical and chemical hazards that may be associated with the work, provide a map to the nearest emergency medical facility, and include material safety data sheets for hazardous chemicals that will be used or produced during the work. A copy of the HASP will be available on-site at all times during field work. The field staff and subcontractors performing field activities will review the HASP prior to beginning field operations, as described in this work plan. Permitting Prior to performing the well destruction activities, necessary documentation will be obtained including well permits from the SJCEHD, encroachment permits from the City of Stockton, and proof of access agreements. Preliminary Field Activities Well locations will be marked or cleared of underground facilities prior to well destruction activities. As required by the California Government Code 4216, Underground Service Alert (USA) North and 811 will be notified at least two working days before drilling activities. Well locations will be marked with white paint to indicate the area of drilling. This will allow USA North members, including local utility companies, to identify and mark the horizontal path of their underground facilities located within the area of drilling. The area will be cleared if no underground facilities are found. In conjunction with USA North and 811, a private utility locator will be utilized for clearing proposed well boring locations for underground utilities.' Well Destruction Activities Stantec will oversee a C-57-licensed contractor pressure-grout seven groundwater monitoring wells (MW-2, MW-3R, MW-4 through MW-8) and eight remediation wells (AW-1, VW-1A/B through VW-3A/B, and VW-4) in accordance with the California well standards. Prior to pressure-grouting activities, the well casing will be inspected for obstructions; if obstructions are found, they will be removed. The well casing will be pressure-grouted with neat cement using a tremie_Pipe system, the well borehole will be air-knifed to approximately 3.5 feet below ra_und surface (bgs), the well casing will be cut at 3 feet bgs,/and-farm a grout mushroom cap. If groundwater is expelled during the grouting process, it will be properly contained, characterized, and disposed. The borehole locations will be backfilled and resurfaced with appropriate materials to match the existing grade. i 2186 Well Destruction Work Plan.doc 2 i