The project site consists of a 1.2-acre property containing a 45,296-square-foot, three-story storage facility. Kleinfelder’s Phase I Environmental Site Assessment (ESA) historical records review revealed the site had been used to manufacture latex masks, included a paint-and-solvent spray booth, and once contained two underground gasoline and diesel fuel tanks that were abandoned and later removed.
The client entered into a California Land Reuse and Revitalization Act Agreement with the California Environmental Protection Agency’s Department of Toxic Substances Control (DTSC) during 2016. To assess recognized environmental conditions (RECs) identified by the Phase I ESA, Kleinfelder performed a Limited Phase II ESA that included sampling of soil, soil vapor, and groundwater beneath the site. Combined results of the Phase II ESAs indicated soil vapor beneath the site’s building contained tetrachloroethylene (PCE) and trichloroethylene (TCE) at concentrations above human health risk-based screening levels, whereas indoor air contained benzene, carbon tetrachloride, 1,2-dichloroethane, ethylbenzene, naphthalene, PCE, TCE, and vinyl chloride concentrations above respective air screening levels.
Kleinfelder performed a Supplemental Phase II ESA, involving three phases. Indoor and outdoor air sampling and concurrent soil vapor sampling were performed during April 2017, October 2018, and April 2019. The suspected PCE and TCE source was an observed sump, adjacent to the site building, on an adjoining off-site property. Kleinfelder subsequently prepared and implemented a Response Plan under the oversight of the DTSC. The Response Action involved performing two semi-annual air and soil vapor sampling events, during August 2020 and February 2021, and human health screening evaluations of the results using both the default commercial worker scenario and a site-specific exposure scenario based on use of the site as a self-storage facility. Kleinfelder’s evaluations of the soil vapor sampling results utilized soil vapor screening levels derived both using the DTSC’s recommended attenuation factor (AF) for an existing commercial building of 0.001 and using the USEPA’s recommended default AF of 0.03.
Based on the analytical results of the Response Action’s two sampling events and the results of the evaluations, Kleinfelder concluded no further action was necessary to protect the health of employees and patrons in the site building, recommending that the DTSC close the site’s environmental case. The DTSC issued the Certificate of Completion of the Response Action on December 24, 2021.
Extra Space Storage, Inc.