So far, only two destruction facilities are complete, with three others under construction. The U.S. developed this arsenal of chemical arms as a Cold War deterrent never intended for use, similar to its nuclear weapon stockpile. But unlike nuclear weaponry, nerve and blister agents appeal to Saddam Hussein and other unstable belligerents because they are relatively easy to produce and undeniably lethal. The latter two disrupt nerve cell activity, throwing muscle response into overdrive. Symptoms include cramping, spasmodic choking, incontinence, convulsions and paralysis of the respiratory system.
Death is usually by suffocation.
In World War I, the Germans introduced chemical weapons by releasing chlorine gas along a 6-km front at Ypres, Belgium. They followed up with mustard gas and the British countered with phosgene compounds. Widespread public revulsion at warfare's chemicalization triggered the Geneva Protocol of 1925, which banned chemical weapons. But at least three countries that signed the treaty broke it later. In the 1930s, Japan used poison gas against China, and Italy employed it in Ethiopia.