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Chemical Agents and Weapons
One should not confuse the terms chemical agent and chemical weapon. A chemical agent is an ingredient, which is not yet a chemical weapon. Chemical agents need to be packed in a proper container such as an artillery shell or a bomb for transport. In Aum Shinrikyo’s sarin terrorist attack in Matsumoto, Japan, it used a homemade sprayer to deliver the sarin. In the Tokyo subway terrorist attack, Aum Shinrikyo members placed sarin in plastic bags, broke open the bags, and let the sarin diffuse by itself. So, you could say a plastic bag containing sarin is a sort of chemical weapon. Some countries have a device attached to an airplane’s wing to spray sarin from the air. With this device, one can spray the gas directly from an airplane instead of packing poisonous gas in bomb. A chemical agent refers to the ingredient and it always requires some mechanism to transport or deliver it.
1.1 Brief History
The first large-scale occurrence of poisonous gas was on April 22, 1915, in Ypres, France, during the World War I. Greenish yellow-colored clouds covered the air of Allied troops and many choked to death. The poisonous gas used was chlorine gas. On this occasion, the Germans used 168 tons of chlorine gas released from 5,730 cylinders. In retaliation, on February 22, 1916, France used phosgene, which was more powerful than chlorine gas. World War I was the peak use of poisonous gas, and many varieties were used by both sides. Phosgene and mustard gas were the two most popular choices (see the following table).
| Country | Phosgene (tons) | Mustard Gas (tons) |
| Germany | 181,000 | 7,600 |
| Britain | 1,362 | 500 |
| France | 15,703 | 2,000 |
| United States | 1,400 | 900 |
Phosgene is a chlorine derivative, as are many other poisonous gases. Why were chlorine-type poisonous gases used? One reason is chlorine is produced in large quantities when sodium hydroxide is manufactured and scientists were happy to make use of all of the excess chlorine.
Because using poisonous gas as a weapon to kill soldiers was so cruel, in 1925, participating countries signed the Geneva Protocol, a treaty prohibiting the use of poisonous gas. The treaty was praised by everyone as a triumph for humanity, but it had one big flaw. The treaty did not prohibit the manufacturing of poisonous gas. If a country had a manufacturing plant, it tended to use it. And if a country had a chemical weapon, it was possible it could use it. Although many countries were signatories of the treaty, some countries disregarded the convention and used poisonous gas anyway. For instance, Japan used poisonous gas against the Chinese during the 1937 to 1945 war in China. China was poor at that time and its troops were not equipped with gas masks or other protective garments as the Japanese soldiers were. Italy used poisonous gas in the Ethiopian invasion in 1935. More recently, Iraq used poisonous gas in the Iran–Iraq War. One interesting point, is that Iraq did not use poisonous gas until it seemed to be losing the conflict. The Iran–Iraq War started in 1980 and ended in 1989, the longest war in modern times. In 1982, Iran pushed back Iraq’s invading forces from Iranian territory, and moreover, Iran started invading Iraqi territory. Saddam Hussein, the head of Iraq, started using chemical weapons in 1982, and eventually used a very large quantity. Iran never expected the use of chemical weapons by Iraq and the Iran offensive against Iraq collapsed.
This suggested several important lessons. One is that the use of chemical weapons in massive quantities is very effective and can change the outcome of war. The second lesson is that one always has to prepare against a chemical attack. The third is that possession of chemical weapons has a “deterrent effect.” In the Pacific War, after the Pearl Harbor attack, Japan forbade the use of poisonous gas because Japan knew the United States had chemical weapons and were afraid of retaliation. In the European theater, poisonous gas was not used because both sides were also afraid of retaliation with poisonous gas. These are examples of chemical weapon possession being a good deterrent. The same seems to hold true for nuclear weapons; that is, nobody dares to initiate the first use of a nuclear weapon...
