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Antonia K. J. Vorster - 2 - 24 November 2008 • Soil gas samples collected in October 2003 identified various volatile organic compounds (VOCs) predominantly consisting of 1,1-dichloroethene (2.8 parts per million by volume [PPMV] maximum) and Freon 11 (9.9 PPMV maximum) that increased in concentration with increasing depth beneath the railroad tracks, with the highest concentrations in closest proximity to the underlying groundwater. • Groundwater has been monitored on a quarterly and annual basis between December 2002 and December 2007 in four monitoring wells. During March 2005, 1,1- dichloroethene (1,1-DCE) was detected in monitoring well TW-2 (located adjacent to the railroad tracks) at a concentration of 39 micrograms per liter (Ng/L), which represents the highest concentration detected above a water quality objective (6.O pg/L for 1,1-DCE) at the site. All chemical constituents have been below their respective water quality objectives since the June 2005 sampling event with the exception of two chloroform detections (1.9 pg/L in December 2006 and 2.3 pg/L pg/L in March 2007 above the water quality objective of 1.1 pg/L) in monitoring well TW-3 (located adjacent to the landscaped area). None of the monitoring wells contained concentrations of chemicals above the respective water quality objectives during the last sampling event in December 2007. Extent defined: Yes Residual Soil Contamination: Soil samples have been collected in the upper five feet below ground surface and have not identified significant concentrations of chemicals of concern with the exceptions of methylene chloride at 17 mg/kg in one surface sample collected from a stained area between the railroad tracks and bis(2-ethylhexyl)phthalate in one surface soil sample at 87 mg/kg in the shipping yard. Soil vapor impacts beneath the railroad tracks increased in concentration with depth (maximum depth at 70 feet below ground surface). Threat to Groundwater: With the exception of the low chloroform detections, all potential constituents of concern have been below water quality objectives in the monitoring wells since June 2005. None of the chemicals tested were above the respective water quality objectives during the last sampling event in December 2007. Threat to Human Health: • Vapor Intrusion Hazard: Using the soil gas data available for the site and the most recent groundwater concentrations, potential indoor air concentrations were estimated using the Johnson and Ettinger model. In addition to using the soil gas and groundwater sample depths and concentrations, the soil was assumed to be sand with the associated default soil properties and a ground temperature of 20 degrees Celsius. The building was assumed to be slab-on-grade using the default building properties. Estimated indoor air concentrations did not exceed residential US EPA Preliminary Remediation Goals or California Human Health Screening Levels. Based on this data, there is not a vapor intrusion hazard at the site. • Dermal Contact Hazard: The one detected soil concentration of 17 mg/kg for methylene chloride is above the PRG of 11 mg/kg for residential soil and below the PRG of 54 mg/kg for industrial soil. The one detected soil concentration of