Van Nuys Airport Industrial Center Interim Removal Action Workplan: OU-3/Plume 3

Van Nuys Airport Industrial Center Interim Removal Action Workplan: OU-3/Plume 3

The Project involves the approval of a Removal Action Workplan (RAW) for the implementation of a soil vapor extraction (SVE) system to address soil vapor as an interim remedy at 7877 Woodley Avenue and 16139 Stagg Street (Site). The Site is a portion of the Van Nuys Airport Industrial Center located adjacent and east of the Van Nuys Airport. Background: The Site consists of two properties located at 7877 Woodley Avenue and 16139 Stagg Street, also referred to as the OU-3/Plume 3 area. These properties are improved with a commercial/industrial building, associated parking areas, and a semi-truck parking lot. Historically, these properties have been used for a variety of commercial and industrial uses including manufacturing facilities, warehouses, airplane hangars, automotive shops, packing and shipping warehouses, and agricultural farms. The Site is currently zoned for commercial/industrial use. The vicinity of the Site is generally commercial and industrial in nature, and the Site does not provide habitat value. Between 2020 and 2023, historical and recent soil, soil vapor, and groundwater investigations were conducted in the OU-3/Plume 3 area. Trichloroethylene (TCE) is identified as the chemical of primary concern (COPC) in the OU-3/Plume 3 area. Based on the results of a Site Soil Investigation (conducted in 2023) and Pilot Test (conducted in 2024), Plume 3 appears to be sourced on the 16139 Stagg Street and/or 7877 Woodley Avenue properties. Plume 3 is predominantly comprised of TCE as a contaminant in soil vapor. Shallow and deep soil vapor concentrations along the northern and eastern property lines are significantly lower than TCE concentrations at central locations of these properties, which is an indication that Plume 3 likely originates from an on-Site source. TCE concentrations in soil vapor generally increase with depth to 110 feet below ground surface (bgs) and then decrease to a depth of 185 feet bgs. On September 1, 2021, Rexford Industrial Realty entered into a Standard Voluntary Agreement (SVA) with DTSC (Docket No. HSA-FY 21/22-021) for the Site. Rexford entered into the SVA for regulatory oversight to address environmental impacts discovered at the Site and to work towards obtaining a No Further Action determination (or equivalent) for the Site. Project Activities: The RAW is an interim removal action to address residual soil vapor by constructing and operating an SVE system. The SVE system will be implemented to remove soil vapor at the Site and treat the vapor stream to prevent VOC emissions to the atmosphere. The SVE will also address residual soil vapor and could be used to prevent the accumulation of residual soil vapor below buildings, thereby reducing potential for vapor intrusion. The SVE system will utilize existing SVE extraction wells and associated multi-depth soil vapor monitoring probes installed on the Site. The SVE system will be installed in the parking lot located in the northwestern portion of the Site (7877 Woodley Avenue) and will consist of the following components: 1. 500 standard cubic feet per minute rotary lobe blower or equivalent; 2. Knock-out tank to remove vapor condensate; 3. Heat exchanger to reduce extracted vapor temperature after the blower; 4. Two 2,000-pound vapor phase activated carbon units; and 5. Seven existing extraction wells. The SVE system could be expanded with installation of additional multi-nested SVE wells in a phased approach based on data collected from the SVE system. The potential locations of additional SVE wells will be immediately to the north and east of the existing building at 16139 Stagg Street (Figure 21 of the RAW). The SVE system will be operated under a South Coast Air Quality Management District (SCAQMD) various locations permit for 12 months and then a site-specific permit beyond 12 months. The project is consistent with applicable state and local environmental permitting requirements including, but not limited to, air quality rules such as those governing VOC emissions and approved by the regulatory body with jurisdiction over the site (e.g., City of Van Nuys, SCAQMD). The installation and operation of the SVE system will require obtaining permits from SCAQMD. For these reasons, the remediation activities described in the RAW would not have the potential to negatively impact any nearby sensitive receptors (such as residential).

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