Kirby Corporation is a domestic tank barge operator, transporting bulk liquid products throughout the Mississippi River System, on the Gulf Intracoastal Waterway, and along all three United States coasts and in Alaska and Hawaii. The Company transports petrochemicals, black oil products, refined petroleum products and agricultural chemicals by tank barge. The Company, through its subsidiaries, conducts operations in two business segments: marine transportation and diesel engine services. On December 15, 2011, the Company completed the purchase of the coastal tank barge fleet of Seaboats, Inc. and affiliated companies. On July 1, 2011, the Company completed the acquisition of K-Sea Transportation Partners L.P. On April 15, 2011, the Company purchased United Holdings LLC. On February 24, 2011, it acquired 21 inland and offshore tank barges and 15 inland towboats and offshore tugboats from Enterprise Marine Services LLC. On February 9, 2011, it acquired from Kinder Morgan Petcoke, L.P.