The U.S. Army is sending a thousand AGM-114M Hellfire missiles, equipped with thermobaric warheads, to Iraq. In 2002, the army rapidly developed this thermobaric (fuel-air explosive) warhead for their hundred pound Hellfire missile, which is fired from the AH-64 helicopter gunship. The new warhead was first used in 2003, and limited quantities of the were available through 2004. But the thermobaric warhead proved particularly effective against buildings, because the fuel air explosive effects (a mist of explosive gas that is ignited after the warhead releases the gas to form the mist) does more damage to rooms adjacent to the one where the twenty pound warhead explodes. The fuel air explosion causes enormous blast pressure, which will injure or kill people in another room without having to blow down the wall. This version became very popular for use in urban warfare, as it kept the damage inside the building hit, causing fewer injuries to nearby civilians and friendly troops.