Huntington Ingalls Industries (HII) has acquired The S.M. Stoller Corporation (Stoller), a leading provider of environmental, nuclear, and technical consulting and engineering services to the Department of Energy, Department of Defense and the private sector. Stoller will be a wholly owned subsidiary of HII and will operate under its NNS division. NNS is the nation's sole designer, builder and refueler of nuclear-powered aircraft carriers and one of only two shipyards capable of designing and building nuclear‐powered submarines.