Petty Officer 1st Class Charles McColligan, damage controlman, instructs Sailors assigned to the Nimitz class nuclear powered aircraft carrier USS Harry S. Truman on the parts and functions of a carbon dioxide fire extinguisher. Truman Sailors are routinely drilled and instructed on how to effectively battle fire aboard ship. Truman and embarked Carrier Air Wing 3 are underway on a scheduled deployment supporting Operations Iraqi Freedom, Enduring Freedom and maritime security operations.