There is one aspect of chemical warfare that the United States is still working on; how to destroy them under difficult circumstances. Iraq is a case in point. Some chemical munitions were destroyed by bombs during the 1991 war, and this reminded everyone that bombing chemical weapons doesn't always destroy them. In fact, it tends to spread them around. This is not a good thing. During the 1991 war, a special technique was improvised for destroying chemical weapons from the air. This involved hitting the target (often a munitions bunker) with high explosives first, then with incendiary bombs. While this burned up, and neutralized some of the chemical agents, it wasn't perfect. So the U.S. Air Force created a new weapon, the HTI-J-1000. This penetrator bomb contains explosives, incendiary chemicals to burn up chemical or biological weapons, as well as chlorine and acids to neutralize the biological agents. There is also a guided cluster bomb containing 4,000 titanium rods for penetrating and destroying chemical or biological bunkers and destroying the contents. There are other weapons, still being developed in secret, that do the same thing using different techniques.