Chemical agents are substances that are intended to cause unpleasant or fatal symptoms in humans. Chemical agents come in a variety of shapes and sizes, ranging from those designed for use in lethal chemical warfare to crowd control agents that temporarily incapacitate people. Because of the dangers of such chemicals falling into the wrong hands, access to them is strictly controlled, and the suspected presence of chemical agents in an enemy nation’s stockpiles has been used as a pretext for international inspection and even war.
Chemical agents have been used by humans for a long time. Ancient Greek warfare accounts, for example, describe the use of flaming ships filled with noxious substances that sailed into the enemy’s ranks to disable them. Chemical agents became more sophisticated as chemistry knowledge grew in the nineteenth and twentieth centuries. Several chemical weapons were used in the trenches during World War One, with many soldiers being injured or killed by substances such as mustard gas.
Following World War I, several countries recognized the potential threat of chemical agents, realizing that they could be used in warfare with lethal consequences. Chemical agents make no distinction between friend and foe, combatant and civilian, and there were several incidents during WWI in which troops accidentally gassed themselves or civilian populations. As a result of these concerns, several chemical weapons bans have been enacted, with signatories agreeing not to manufacture or stockpile chemical agents for military purposes.
Most countries use a classification system to identify chemical agents in order to comply with such bans. Chemicals in the first class have no other purpose than to be used as chemical weapons, and they are frequently expressly prohibited. Chemicals with non-military applications are grouped together in the second class, while common chemicals with a wide range of uses, including potential military applications, are grouped together in the third class. Companies that make chemicals in the second and third classes may be required to keep meticulous records of who they sell to and how much they sell.
Chemical agents have a wide range of effects. Some attack the lungs, causing people to choke to death, while others, when inhaled, cause blisters on the skin and in the lungs. Chemical agents can also disrupt protein synthesis in the body, harm the nervous system, and render people temporarily unconscious. Many police departments use short-acting chemical agents designed for use in riots and mobs to disperse crowds without causing permanent harm; tear gas is an example of a chemical agent that might be used in such situations.