VERTEX provided environmental consulting services for the construction of a mixed-use development in the Potrero Hill neighborhood of San Francisco, California. The site was historically operated as a tannery and glue factory and later as a bulk oil storage facility. As such, soil and/or groundwater underlying the site contained elevated concentrations of petroleum constituents, chlorinated solvents, and metals. At the start of the project, VERTEX reviewed the results of prior environmental investigations at the site and provided the Client with an understanding of the environmental risks associated with the proposed site reuse as well as an ASTM Phase I Environmental Site Assessment (ESA) for lending purposes. VERTEX also designed and implemented a supplemental Limited Subsurface Investigation (LSI) to close data gaps in the earlier assessments and obtained data needed to accommodate the specific construction plans for the redevelopment.
Due to the location of the site within the portion of the city governed by the Maher Ordinance, VERTEX worked with the San Francisco Department of Public Health (SFDPH) to guide the site through the Maher Program. To enter the site into the process, VERTEX prepared a Site Mitigation Plan (SMP) that sets management protocols for the handling, moving, stockpiling, and disposing of soil from the site as well as requirements for soil to be imported to the site. The SMP also provided guidelines for the management of health and safety for site workers and construction workers during redevelopment through a detailed site-specific Dust Control Plan and Health and Safety Plan. In order to protect future users of the site, VERTEX developed a conceptual plan for the installation of a passive sub-slab depressurization system (SSDS) with the addition of a chemically resistant vapor barrier to address potential vapor intrusion to the proposed site building. In addition, future direct contact with site soils were prevented through the operation and maintenance of the site foundation for use as a site-wide cap.
The site received approval from the Maher Program, and VERTEX provided construction-phase consulting services including environmental oversight, dust monitoring, SSDS design, and environmental reporting.