Flying unescorted in the face of severe enemy attack, the 16th bombed the Maruzen Oil refinery at Shimotsu on the night of 2 July 1945; the Mitsubishi refinery and Kawasaki oil installations at Kawasaki on the night of 12–13 July 1945, and the coal liquefication plants at Ube on 22–23 July 1945.
Despite the hazards of bad weather, fighter attacks, and heavy flak, the 331st bombed the coal liquefaction plant at Ube, the Mitsubishi-Hayama petroleum complex at Kawasaki, and the oil refinery and storage facilities at Shimotsu, in July and August 1945, and received a Distinguished Unit Citation for the missions.