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Table 2 <br /> Development of California Human Exposure-Based Screening Numbers for TPHg <br /> Chevron Facility#306620(Former Unocal#5098) <br /> 5400 and 5606 Pacific Avenue, Stockton, California <br /> Toxicity Value Residential Indoor Air Commercial/Industrial Indoor Air Soil Gas CHHSLs <br /> CHHSLnc Minimum CHHSLc CHHSLnc Minimum Residential Commercial <br /> URF REL CHHSLc(b) (b) CHHSL (b) (b) CHHSL (c) /Industrial(d) <br /> Compound (ug/m')-' ug/m' ug/m' ug/m' ug/m' ug/m' ug/m' ug/m' ug/m' - ug/m' <br /> TPH as Gasoline NA 5.00E+01 (a) NA 5.21E+01 5.21E+01 NA 7.30E+01 7.30E+01 2.61 E+04 7.30E+04 <br /> Notes: <br /> OEHHA-Office of Environmental Health Hazard Assessment. <br /> CHHSLc-California Human Health Screening Level based on a carcinogenic endpoint. <br /> CHHSLnc-California Human Health Screening Level based on a noncarcinogenic endpoint. <br /> DTSC-Department of Toxic Substances Control. <br /> DTSC,2009-DTSC Interim Guidance Evaluating Human Health Risks from Total Petroleum Hydrocarbons(TPH),June 16,2009. <br /> NA-Not available. <br /> REL-Reference exposure level. <br /> URF-Inhalation unit risk factor <br /> (a)DTSC(2009)recommended value for C9-C16 aromatic hydrocarbons. <br /> (b)Calculated in accordance with the methods described in Appendix B of CaIEPA,2005.CalEPA OEHHXs Human Exposure-Based Screening Numbers <br /> Developed to Aid Estimation of Cleanup Costs for Contaminated Soil.January 2005 Revision. <br /> (c)Minimum CHHSL divided by the default attenuation factors for current residential slab-on-grade structures(0.002)recommended by DTSC. Vapor Intrusion <br /> Guidance Document. Interim Final.February 7,2005. <br /> (d)Minimum CHHSL divided by the default attenuation factors for current commercial slabon-grade structures(0.001)recommended by DTSC. Vapor Intrusion <br /> Guidance Document. Interim Final.February 7,2005. <br />