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contaminants in soil and sediment were determined to pose a risk to humans and wildlife and therefore require remediation. The primary drivers of risk at Site 47 are the presence of arsenic in soil and OCPs in sediment. The remedy proposed in this Site 47 RAP addresses contaminants in soil and sediment. Site 47 RUFFS considered possible cleanup methods (referred to as remedial technologies), which were combined into five remedial alternatives that were evaluated in detail: • Alternative 1,No Action; • Alternative 2, Existing Durable Cover, Fence, and Institutional Controls (ICs); • Alternative 3, Excavation with On-Site Consolidation, Existing and New Durable Cover, and ICs; • Alternative 4, Excavation(to 2 feet) with Off-Site Disposal (Backfilled with Clean Fill), Existing Durable Cover, and ICs; and • Alternative 5, Expanded Excavation with On-Site Consolidation, Existing Durable Cover, Expanded New Durable Cover, and ICs. The remedy proposed in this Site 47 RAP is Alternative 5,Expanded Excavation with On-Site Consolidation, Existing Durable Cover, Expanded New Durable Cover, and ICs. Based on the comparative analysis, Alternative 5 is the most effective and viable alternative because it will support a proposed development(called Project Sierra) with near-term economic benefits to the region. Alternative 5 involves installing of a durable cover that is integrated with the Project Sierra development, maintaining the cover over time, and establishing ICs to restrict future land use and activities to minimize exposure to remaining contaminants of concern(COCs) and contaminants of ecological concern(COECs) in soil. The proposed remedy would be implemented in concert with Project Sierra, which involves construction of a new warehouse and related facilities as shown on Figure 4 (e.g.,parking and outdoor storage areas, subsurface utilities, and new railroad spurs). Alternative 5 would be implemented in phases and take approximately two years to implement. Implementation is expected to begin in 2023 and be completed by 2025. During the Remediation, about 57,000 cubic yards of contaminated soil would be excavated and consolidated within the planned Warehouse and Outdoor Storage Area footprint (Figure 4), and then covered with clean soil and a concrete building foundation or concrete slab. Other areas of Site 47 would be covered with a combination of clean soil and hardscape surfaces (e.g., concrete slabs and asphalt-concrete pavement). The proposed covers within the development area would be combined with covers and ICs in areas to the west and east. The durable covers would prevent future site users and wildlife from contacting the underlying contaminated soil and sediment. The covered areas would be inspected and maintained regularly, and ICs would also be implemented to protect human health by restricting land uses and activities that are incompatible with the selected remedy. A 30-day public comment period was conducted for this Site 47 RAP, from August 10, 2023 to September 12, 2023. A community update and public notice were issued, and a public virtual Site 47 RAP for Soil ES-2 October 2023