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89 also lower than the average indoor basement radon concentrations of 2 to 4 pCi/L (p. 29). With respect to endangered species, a review of the NEPASearch database indicated no natural areas such as federal lands, wilderness preservation, conservation easement, protected areas, or critical land habitat are located at the site or within one-eighth of a mile of the project component site. However, three California endangered species are identified within one-eighth of a mile of the site: the Santa Cruz kangaroo rat, the San Francisco garter snake, and the hoary bat. The western snowy plover is also identified within one mile of the project component site. And the U.S. Fish and Wildlife Service database indicates many threatened or endangered species in San Mateo County (pp. 29-30). (See item IV, Biological Resources for more discussion.) Regarding lead-based paint, the Phase I ESA concluded that “it’s possible that lead- based paints were used historically on facility structures” though during the site visit the paint of observed surfaces was determined to be in fair condition (p. 30). With respect to lead in drinking water, the City’s water quality report and other analytical reports of drinking water indicated that the water supply met State and Federal drinking water health standards (p. 30). Regarding regulatory compliance, no environmental permits have been maintained for the facility nor is it registered as a generator of hazardous wastes (p. 30). With respect to wetlands, the maps included in the NEPASearch report, obtained from the National Wetland Inventory, identified no wetlands on the project component sites (p. 30). The Phase I ESA also discussed the potential for migration of contamination from an offsite property with petroleum hydrocarbon impacts to the groundwater. The property, located at 1629 Main Street (Motloch Parcel), is listed with a status of “closed” in the leaking underground storage tank database. The Phase I ESA determined that “No known or potential sources of contamination have been identified in relation to the site; if contamination associated with the off-site property is found to have migrated onto the subject site, it is expected that any remedial activities would be the responsibility of the entity(ies) named in the listing or other designated responsible party and not the [Housing Component] site owner.” The Phase IESA did not identify a release or a suspected release, nor the potentially material threat of a release, so this item was not considered an REC (pp. 4-5). Limited Phase II Environmental Site Assessment Memorandum (Limited Phase II ESA) A site-specific Limited Phase II Environmental Site Assessment Memorandum has been prepared for the 920 Shasta Street project component (Limited Phase II Environmental Site Assessment Memorandum, 920 Shasta Street, Redwood City, California; June 15, 2021) (Limited Phase II ESA). The purpose of the Limited Phase II ESA was to evaluate potential offsite vapor migration and include recommendations based on the findings. The Limited Phase II ESA collected samples from ten (10) temporary soil vapor probes onsite (p. 1). The results indicate that while benzene was not detected above the minimum laboratory detection limit (MDL) of 4.4 μg/m3, it could be present above the San Francisco Bay Regional Water Quality Control Board (SFBRWQCB) residential environmental screening level (ESL) of 3.2 μg/m3 (p. 3). Tetrachloroethylene (PCE) was detected at 1,500 μg/m3, which is above the commercial and residential ESL of 15 μg/m3 and 67 μg/m3, respectively (p. 3). Chloroform was detected at 10 μg/m3, above the residential ESL of 4.1 μg/m3 but below the commercial ESL of 18 μg/m3, the source likely related to leaky sewer or water lines (p. 3). The Limited Phase II ESA determined that, “In summary, based on the limited soil vapor results from this investigation, the primary chemicals of potential concern at the Site are PCE and benzene. The source of these compounds is unknown but are likely related to an offsite source(s) (e.g., groundwater, soil vapor encroachment, and/or sewer gas) migrating onto the Site” (p. 4) as indicated in the Phase I ESA. The Limited Phase II ESA made the following recommendations (p. 5):  Conduct a passive soil gas survey using Beacon Environmental passive soil gas samplers (PSGs) to further assess sub-surface soil vapor conditions at the Site.  Perform a limited soil and groundwater assessment to identify potential contaminant sources in other environmental media.  Submit this Memorandum [the Limited Phase II ESA] to the appropriate regulatory agency for review.  Install a passive sub-slab depressurization system (SSDS) with a vapor barrier, should the Site be redeveloped. It is likely a regulatory agency would require an SSDS to be installed, operated and maintained to protect future residential occupants from potential vapor intrusion. The additional site assessment tasks mentioned above would provide further information regarding potential post-development vapor mitigation strategies. Post-Limited Phase II ESA Activities: Subsequent to preparation of the Limited Phase II ESA, the Housing Component developer entered into a California Land Reuse and Revitalization Act agreement with the Department of ATTY/RESO.0031/CC RESO CEQA GUIDELINES (901 EL CAMINO REAL) REV: 04-22-25 VR Page 89 of 148