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Table 4 <br /> Summary of Indoor Air Modeling Inputs6 <br /> Chevron Facility#306620 (Former Unocal#5098) <br /> 5400 and 5606 Pacific Avenue, Stockton, California <br /> EXPLANATION: <br /> cm=Centimeter <br /> oC=Degrees Celcius <br /> CaIEPA(2008)=Califomia Environmental Protection Agency.OEHHA Chronic Reference Exposure Levels.December 18,2008. <br /> CaIEPA(2009a)=California Environmental Protection Agency.OEHHA Toxicity Criteria Database, July 21,2009. <br /> DTSC/HERD=Department of Toxic Substances Control/Human and Ecological Risk Division. <br /> OEHHA=Office of Environmental Health Hazard Assessment. <br /> NA=Not available. <br /> SCS=Soil Classification Service. <br /> TPH=Total Petroleum Hydrocarbons. <br /> TPH guidance(CaIEPA,20096)=DTSC/HERD Interim Guidance,Evaluating Human Health Risks from TPH.June 16,2009. <br /> USEPA=United Stales Environmental Protection Agency. <br /> 'Johnson 8 Ettinger(J&E)Model,Version 3.1,Febuary,2004,adjusted with DTSC/HERD recommended default values. <br /> 2Based on the site-specific geotechnical testing. <br /> 'CaIEPA,2005a. Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air.Department of Toxic Substances Control California, <br /> Environmental Protection Agency.December 15,2004(Revised February 7,2005). <br /> 4USEPA,1991a. Human Health Evaluation Manual:Supplemental Guidance:Standard Default Exposure Factors.OSWER Directive 9285.6-03,March 25,1991 <br /> 5Toxicity criteria chosen for closest aliphatic carbon fraction range based on guidance In Table 2. <br /> °Users Guide for JE model,62 degrees F for Stockton,CA. <br /> 7 Selected to represent site-speck soil type made up of day,send,and sill.However,this parameter is not used in the J&E Model because <br /> site-specific geotechnical parameters and the default Qsoil are entered directly. <br /> °Inputs not referred to on this table are set at default values. <br /> 'Tentatively identified compounds were grouped into one of the carbon fraction ranges for which toxicity criteria are available in Table 2 of the TPH guidance(CaIEPA,2009b). Then toxicity criteria <br /> recommended in Table 2 were used to evaluate potential risk/hazard associated with each carbon fraction range. <br /> 60146576 3 of 4 AECOM <br />