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SOIL INVESTIGATION WORK PLAN ' Pilkington North America,Inc. 500 East Louise Avenue Lathrop, California 1.0 INTRODUCTION This work plan was prepared by Condor Earth Technologies, Inc. (Condor)to describe the installation of ' up to eight proposed soil borings at the Pilkington North America, Inc. (PNA) facility located at 500 East Louise Avenue (Site) in Lathrop, California (Figure 1, Appendix A). Condor prepared this Work Plan at the request of Mr. Reyes Franco, PNA representative, to address the comments in the September 7, 2010 ' letter from Mr. Gerald Djuth of the California Regional Water Quality Control Board, Central Valley Region (Regional Water Board). The purpose of the work is to investigate whether the source of the light non-aqueous phase liquids (LNAPL) currently present in several of the Site's product recovery wells is ' from residual diesel-saturated soils associated with a historic (1996) leak, or potentially from an active leak from another source. This Work Plan also addresses inspection and integrity testing of the Site's current diesel fuel lines and tanks. The proposed boring locations are shown on Figure 2, ' Attachment A. All work conducted by Condor will be performed under the supervision of a California Professional ' Geologist and in accordance with San Joaquin County Environmental Health Department(SJCEHD) and Regional Water Board guidelines and requirements. This Work Plan contains a background summary, a description of the Site geology, and a discussion of the methods and procedures for the planned work ' including a description of the field work, field and laboratory analyses, and a project schedule. 2.0 PROJECT BACKGROUND ' An investigation to evaluate suspected leaking underground piping associated with a 10,000 gallon above ground diesel tank(AST) and standby generator was conducted on 7uly 24, 1996. The product piping was suspected to have leaked due to an unspecified volume of inventory loss. The investigation included the ' excavation of a portion of the underground piping at a jointed section where the leak likely occurred. Approximately 15 cubic yards of soil were excavated during the investigation. The excavation was terminated at approximately 13 feet below ground surface (bgs) when floating diesel product was encountered. All soil excavated had a strong diesel odor and soil samples collected from the excavation sidewalls at five feet, eight feet, and 11.5 feet bgs contained elevated concentrations of total petroleum hydrocarbons quantified as diesel (diesel), and benzene, toluene, ethyl benzene, and total xylenes ' (BTEX). On July 25, 1996, the product level in the excavation was measured at an approximate depth of nine feet ' bgs. The product thickness could not be determined since no groundwater interface was noted and it appeared that a minimum of two feet of diesel product was present at the bottom of the excavation. A sample collected from the excavation for water content analyses indicated 128 parts per million (ppm) of ' water content. Condor and Oil Equipment Services of San Andreas, California, installed a one-inch, air powered, diaphragm pump and product recovery piping at the Site on August 2, 1996. Approximately 520 gallons ' of diesel were pumped during the initial product removal phase. On August 6, 1996, Evergreen Inc. of Newark, California, pumped the product from the tank, removed an additional 225 gallons directly from 1 ' i1� CONDOR