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Abdelwahed Facility, Ultramar Site No. 13792 May 9, 2013 Stockton, California NFAR Request and Well Destruction Work Plan indicate that the risk to on-site workers is below the level of concern. Site data and the site conceptual model demonstrate that no sensitive receptors are threatened. 16. No WET or TCLP analyses were conducted on soil samples. WORK PLAN FOR WELL DESTRUCTION In an e-mail dated 25 January 2013, the EHD requested that a work plan to destroy all wells associated with the site be included in this investigation report. Subsequent to assignment of NFAR status to the site, Ultramar shall obtain permits to destroy all site wells in accordance with the California Well Standards Bulletins 74-81 and 74-90 and EHD Well Standards. Wells to be destroyed include eleven groundwater monitoring wells (MW -2 through MW -4 and MW -6 through MW -13), five vapor extraction wells (VW -1 through VW -5) and two sparge wells (S W-1 and S W-2). Wells MW -2 through MW -4, MW -8, MW -9, VW -1 through VW -5, SW -1 and SW -2 are located on the subject site property (APN 169-08-55). Wells MW -6, MW -7 and MW -10, MW -11 and MW -12 are located sidewalk areas in City of Stockton rights-of-way (ROWs). One permit application shall be submitted for wells located on the subject site, and one permit shall be submitted for wells in Stockton ROWS. No petroleum hydrocarbons have been detected in groundwater samples from wells MW -4, MW -7 and MW -8 for at least the past two years and these well are located outside of the area of residual contamination; it is recommended that these wells be destroyed by the pressure grout method. It is recommended that the remainder of the wells be destroyed by over- drilling. The estimated grout volumes required to destroy the wells are summarized in the enclosed table. Well destruction work shall consist of the following tasks: Task I Select and schedule a C-57 licensed drilling contractor to provide well destruction services; obtain permits that may be required from the City of Stockton; obtain required permits from the EHD; arrange for an on-site bin to contain drill/well cuttings; contact USA to mark underground utilities in the areas of the wells; and update the Site Health and Safety Plan to include well destruction activities. Task 2 Disconnect VES and sparge piping from connected wells; drill -out selected wells to total width and depth of the original bore hole; backfill borings greater than 30 feet deep with neat cement via tremie set to within 5 feet of total depth of the borings; pour neat cement grout from surface for drill -outs less than 30 feet bsg (VW -3 and VW -4); top off neat cement back fill until stabilized within 2 feet of surface grade; emplace native, sandy or base material and restore the surface, as required for each well location. 1792 NFAR rpt.doc Project No. 1792.26 10 HORIZON ENVIRONMENTAL INC.