Operable Unit (OU) 6, Site 3 is a Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) site located on the southeast side of the Naval Weapons Station (NWS) Earle Mainside, west of the “F” Group bunkers and Fire Rescue Road 126. Site 3 includes a closed 5-acre landfill used for the disposal of paints, paint thinners, solvents, varnishes, shellac, acids, alcohols, caustics, pesticide containers, rinse water, wood, and asbestos. The Record of Decision (ROD) for OU 6, Site 3 was signed by the United States Environmental Protection Agency (EPA) on August 15, 2006 to address chemicals of concern (COCs) that included metals in soil and groundwater. The ROD required consolidation of contaminated soil within the landfill, installation of a low permeability landfill cap, Land Use Controls (LUCs), and long-term groundwater monitoring. The LUCs included establishment of a Classification Exception Area (CEA), prohibiting use of site groundwater, prohibiting development for housing, schools, childcare facilities, or playgrounds, and prohibiting digging or disturbance of the landfill cap. Construction of the landfill cap was completed in June 2003. In October 2019, the EPA approved the Explanation of Significant Differences (ESD) for Site 3 which removed the ROD requirements to establish a CEA and conduct long-term groundwater monitoring as the groundwater contaminants were proven to be naturally occurring. Site 3 is still subject to soil LUCs, and Five-Year Reviews.