SITE INFORMATION AND CORRESPONDENCE

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M. Scott Mansholt - 2 - 18 November 2009 Vernalis Offsite NFAR Analysis of groundwater constituents reported TPH as diesel (TPHd) at concentrations of 160 micrograms per liter (pg/L) and 240 pg/L in samples from two borings. The remaining samples were ND at the detection limit for TPHd as well as other petroleum hydrocarbons compounds of potential concern (COPCs) which were at or slightly above respective method detection limits (MDLs). SAIC concluded that the downgradient extent of affected groundwater and soil was adequately defined. In July 2008, Central Valley Water Board staff notified Chevron that soil and groundwater had been defined at the Site and additional characterization was not needed. The property owner informed Chevron that their access agreement was being terminated and asked that the wells be removed. SAIC submitted a workplan and the wells were subsequently destroyed in August 2008. SAIC provided the following in the NFAR documentation report.- 0 eport:• A search of Department of Water Resources (DWR) files did not identify water supply wells within 2,000 feet downgradient (east) of the Site. Seven water supply wells identified up/crossgradient approximately 800 feet from the Site, have surface seals of at least 50 feet. It is unlikely these wells would be affected by the TPH compounds found at the Site. • With the exception of TPHc at 380 mg/kg in a sample from one foot bgs, the Site COPCs were not present in soil at concentrations exceeding applicable environmental screening levels. Considering the depth and distance from the historical pipelines, the 380 mg/kg TPHc reported is attributed to current site activities and not associated with the former pipelines. • The evaluation of risk to human health was based on conservative residential setting and/or ecological screening levels. TPH concentrations present in soil that are attributable to the former crude oil pipeline leaks do not present a human health risk, and the property is suitable for residential development. • The concentrations of total dissolved solids (TDS) in groundwater from investigative borings exceed State of California and federal TDS standards for drinking water as well as for agricultural use criteria. SAIC's report indicated it was unlikely new water supply wells would be installed in the vicinity. • A one-time detection of TPHd at a concentration of 320 micrograms per liter (pg/L) was reported in groundwater from one of the monitoring wells. Prior and subsequent monitoring events did not report petroleum hydrocarbons present in this well. In addition, in the unlikely event a water supply well is installed at or near the Site, a surface seal of at least 50 feet bgs is required which is deeper than the vertical extent of affected groundwater. • Site groundwater monitoring wells were properly destroyed in August 2008. • SAIC concluded that soil and groundwater impacts have been delineated, the project groundwater monitoring wells were properly destroyed, applicable human health risk