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Facility and PBR Units Closure Work Plan <br /> 1848 and 1856 Field Ave., Stockton, California <br /> 3.3 Action Plan for Issues and Potential Issues at 1856 Field Avenue <br /> 3.3.1 Petroleum Hydrocarbons from Air Compressors <br /> r <br /> Tyco will excavate TRPH contamination until the remaining soil meets the cleanup goals presented in Section <br /> r 4.Due to the relatively viscous nature and apparently limited release rate of this contamination,Tyco intends to <br /> excavate the contaminated area without earlier characterizing the lateral and vertical extent of contamination. <br /> ` As a result,the specifics of the excavation program are still uncertain. Our best description of the likely soil <br /> excavation program follows: <br /> Prior to excavation, Earth Tech will coordinate with the County regarding the excavation schedule and <br /> ` confirmatory sampling plans. An Earth Tech subcontractor will perform the excavation, with oversight by <br /> Earth Tech.Excavation will be performed in stages,with the removal of apparently contaminated soil based on <br /> visual and photoionization detector (PID) readings, and the collection of confirmatory samples after <br /> excavation. The initial excavation is not anticipated to be larger than 6 feet by 6 feet, and 3 feet deep. All <br /> excavation will be no more than three feet below the top of grade without a geotechnical engineer's review, <br /> because the building is immediately adjacent,information regarding building foundation construction is not <br /> available for review,and building integrity could be compromised if excavations are deeper than any nearby <br /> ` footings. If contamination is shown to extend more than three feet below grade, Earth Tech geotechnical <br /> engineers will evaluate the situation prior to any deeper excavation. If necessary because of soil and footing <br /> ` stability concems, alternative remedial options will be considered. <br /> A minimum of three confirmatory samples will be collected from the excavation floor or sidewalls,with one <br /> additional confirmatory sample for every additional 10 cubic yards (cy) of excavation after the first 10 cy. <br /> Confirmatory samples will be tested for TRPH by EPA Method 5520 at a state-certified laboratory. Upon <br /> receipt of the confirmatory sample results and comparison to the cleanup goals presented in Section 4, <br /> additional excavation may be performed as appropriate after re-mobilizing the field crew. <br /> ` Though the area to be excavated is protected by an existing barbed wire-topped facility fence,the compressor <br /> area excavation will be surrounded by security fencing in order to protect workers or trespassers.The security <br /> fence will remain in place until the excavation is backfilled. The backfilled area will be compacted to an <br /> estimated 90 percent compaction before the area is re-paved. <br /> L:IWOW690991GeneraAield WPOeldAve WPAug03 re2.doc 11 August2003 <br />