Machine Gun Abutment – U.S. Coast Guard Base Elizabeth City, NC

This Project involved the investigation, removal action design, and demolition activities completed for the machine gun abutment (MGA) structure and surrounding area at United States Coast Guard (USCG) Base Elizabeth City in Elizabeth City, North Carolina. Specifically, this project addressed the removal and demolition of the MGA structure and associated lead- and lead shot-impacted soils. The MGA, prior to excavation, was a reinforced concrete structure (i.e., bullet backstop) surrounded by an earthen mound, approximately 65 feet wide, 120 feet long at its base, and 15 feet high.

The soil removal action included excavation and off-site disposal of soil with lead concentrations greater than the cleanup goal of 250 milligrams per kilogram. Prior to removal actions, activities included: using X-ray fluorescence to delineate areas with elevated lead concentrations; a habitat assessment; a Consistency Certification; and a supporting Coastal Zone Management Act Determination Report. The removal action resulted in a complete demolition of the MGA, razing the earthen mound, and restoring the surface to align with grades of the surrounding area. Unexploded ordnance support and screening by soil sifting was conducted to remove munitions and other metallic material. Approximately 2,143 tons of soil and concrete, including 448 tons of hazardous soil, were generated during the demolition of the MGA and designated for offsite transportation and disposal.  The phases of this project progressed from remedial design to remedial action, to construction completion, and the North Carolina Department of Environmental Quality issued a No Further Action determination for the MGA in January 2023.