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� OUR Product Recovery ' Product recovery activities began on July 24, 2006. Recovery activities included placing absorbent pads to collect product from the ground surface and from containment pads within the ' manifold area. Approximately 84 gallons of product was recovered from the interior of the back-pressure valve containment pad and pumped into the onsite oil-water separator using pneumatic pumps. An estimated 25 gallons of additional product was recovered from a surface ' water catch basin located to the northeast of the containment pad and transferred to the onsite oil-water separator. This catch basin is not connected to the regional sewer system. ' Recovery activities also included hand excavating trenches and installing steel sumps to allow skimming of product from the groundwater surface encountered in the trenches. Forty exploratory boreholes were advanced by hand to assess the extent of product observed on shallow groundwater ' and to determine the area of soil requiring excavation within the manifold area. Twenty of these borings within the area of visibly stained surface soil encountered product at the depth of groundwater and accumulated product was removed from these borings and transferred to the oil-water separator or recovered using absorbent pads. Product recovery from the trenches, sumps, and subsequent excavation areas continued until no ' additional product was observed on exposed groundwater or within the excavations. An additional 48 gallons of non-aqueous-phase hydrocarbons (NAPH) and approximately 450 gallons of petroleum hydrocarbon-impacted groundwater was recovered and transferred to the onsite oil-water separator. In addition, 17 drums of absorbent pads and PPE were generated during product recovery activities. ' Product Sampling Activities To evaluate the type(s) of product potentially released from the back-pressure valve, product ' samples were collected on July 24, 2006 into 40-milliliter VOA vials from the primary product recovery trench at the site (sample PS-1; Figure 3). The collected samples were submitted to Alpha Analytical, Inc. (Alpha) a California state-certified laboratory located in Sparks, Nevada, under strict chain-of-custody protocol and analyzed for total petroleum hydrocarbons (TPH) scan for carbon range distribution on a 24-hour turnaround schedule. Chain-of-custody documentation for these product samples is included in Appendix A. ' Soil Excavation ' Soil excavation activities were initiated on July 24, 2006 in the immediate vicinity of the back-pressure valve assembly. Initial hand excavation activities involved removing visibly affected ' surface gravel within the manifold area. Following removal of the stained gravel cover, visibly stained soil within the affected area was observed primarily adjacent to vertical piping penetrations into the subsurface. These visibly stained soils were hand excavated to a maximum depth of 3-feet below ground surface (bgs) where groundwater was encountered. ' 3