Between 2014 and 2017, Lockheed Martin and its contractors removed over 3,285 truckloads, or 55,500 cubic yards, of sediment contaminated with polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and metals from nearly 12 acres of Dark Head Cove and Cow Pen Creek during three construction seasons. To create a clean and protective cove and stream bed, they placed 488 truckloads, or 10,263 tons, of sand over the areas where contaminated sediment was removed, and placed 21 truckloads, or 450 tons, of streambed sand and gravel organic mix upstream in Cow Pen Creek. Native plants and submerged aquatic vegetation were planted as part of the project, and Lockheed Martin will monitor their growth to ensure restoration is successful. As a final step, 118 truckloads, or more than 2,500 tons, of activated carbon similar to that used in home water filters were placed on an additional 13.7 acres of Dark Head Cove floor where polychlorinated biphenyl concentrations were low enough that dredging was not warranted.