AgdaPkt 2017-01-09 Closed and Joint

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TA. - Page 70 A site-specific Phase I Environmental Site Assessment has been prepared (Phase I Environmental Site Assessment, 603 Jefferson Avenue, Redwood City, California; ENGEO Incorporated; June 19, 2015, Revised February 23, 2016) (Phase I ESA). The current building at 603 Jefferson was constructed circa 1962 for commercial uses, and has since been occupied by various commercial tenants (Phase I ESA p.11 and Appendix B). The Phase I ESA discusses the site of the current building as well as adjacent and nearby properties. The information below is taken directly from the Phase I ESA and appendices. The Phase I ESA was conducted in conformance with the scope and limitations of American Society for Testing Materials (ASTM) Standard Practice E1527-13 ("Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process" — the ASTM Standard') and the Environmental Protection Agency (EPA) "Standards and Practices for All Appropriate Inquiries. " The Phase I ESA evaluated the following three types of environmental conditions, as described below: Recognized Environmental Conditions, Controlled Recognized Environmental Conditions, and Historical Recognized Environmental Conditions. Recognized Environmental Conditions (RECs) are defined by the ASTM Standard as the presence or likely presence of any hazardous substances or petroleum products in, on, or at a property: (1) due to release to the environment; (2) under conditions indicative of a release to the environment; or (3) under conditions that pose a material threat of a future release to the environment. One on-site REC was identified (Phase I ESA pp. 1, 2, 7, and 8). Further detail is provided below. ENGEO performed a site reconnaissance and records research and did not find documentation of past soil and groundwater impairments associated with the current or past use of the project site. However, ENGEO located documentation of limited on-site soil and groundwater impact. This documentation identified intermittent, low- level, isolated soil impacts at the site likely attributable to groundwater flow from an unidentified off-site source. A previous analysis of soil and groundwater samples was conducted by Tetra Tech in December 2014 (2014 Tetra Tech Report). 2014 Tetra Tech Report soil findings: ■ three soil samples exhibited lead concentrations in excess of residential screening levels utilized by the San Francisco Bay Regional Water Quality Control Board (RWQCB) and the California Department of Toxic Substances Control (DTSC) for shallow soil in a residential setting; ■ numerous soil samples exhibited nickel and chromium concentrations in excess of threshold values; ■ one soil sample exhibited a total petroleum hydrocarbons (TPH)-motor oil concentration above the screening value (though this was not considered indicative of environmental impact for TPH-motor oil because the remaining soil samples did not exhibit detectable TPH-motor oil concentrations); ■ selected soil samples exhibited detectable concentrations of volatile organic compounds (VOCs) such as acetone, tetrachloroethene (PCE), toluene, and trichloroethene (TCE); and ■ several soil samples exhibited phenol concentrations in excess of RWQCB screening levels with respect to groundwater protection. ENGEO soil conclusions: ENGEO concluded, based on the 2014 Tetra Tech Report, that although selected soil samples exceeded the residential screening levels for lead and TPH-motor oil, the detection appeared isolated and would not be considered an environmental impact, largely due to the required excavation of the soil as part of the project (Phase Ipp. 7 and 8). As a condition ofproject approval, the project would be required to prepare a soil and groundwater managementplan, subject to County GPP review and approval (described below), which wouldprovide for the safe removal and disposal of excavated material from the project site (Phase Ipp. 24 and 25). 2014 Tetra Tech Report groundwater findings: ■ none of the groundwater samples exhibited detectable concentrations of TPH-diesel or semi -volatile organic compounds (SVOCs); ■ one sample exhibited a detectable concentration of TPH-motor oil; ■ several samples exhibited detectable TPH-gasoline concentrations in excess of groundwater screening levels for drinking water; ■ several VOCs were detected in excess of respective drinking water levels, including benzene, PCE, and TCE; and ■ several other VOCs were also detected but were below respective drinking water levels. ENGEO groundwater conclusions: ENGEO concluded, based on the 2014 Tetra Tech Report, that although the groundwater contamination was likely attributable to an off-site groundwater source (Phase Ipp. 7 and 8), the project would need to implement a vapor intrusion system to address the migration of volatile chemicals from the subsurface into the overlying building 23