Chemical weapons are chemicals which have toxic properties which can be utilized in warfare or crowd control. Thanks to the Geneva Protocol on 1925, the use of chemical weapons is prohibited in warfare, although some nations reserve the right to retaliate if they are struck with chemical weapons. Stockpiling of chemical weapons has been curtailed by the Chemical Weapons Convention of 1993, which mandates destruction of such weapons, along with the cessation of chemical weapons development programs.
The history of chemical weapons is ancient, although humans certainly refined them to new levels in the 20th century. However, historical evidence suggests that people have been utilizing chemical weapons since at least the fifth century BCE, when the Spartans set fire to noxious substances under the walls of the Athenians in an attempt to choke them out. Until the 20th century, many chemical weapons were asphyxiants, designed to disable people by choking, while the First World War marked the development of more sophisticated and devastating chemical weapons.
Like drugs, chemical weapons are divided into schedules. Schedule I chemical weapons have no potential use other than as weapons; nerve agents are an example of such weapons. Schedule II chemicals have some potential use; for example, the precursors of some nerve agents are used for other applications, making it difficult to ban them. Schedule III includes chemicals with a number of potential commercial uses, like chlorine.
People also classify chemical weapons by their effects. Nerve agents interrupt with the functioning of the nervous system, causing various degrees of debilitation. Sarin, V-agents like VX, tabun, and many insecticides are nerve agents. Asphyxiants, as you might imagine, cause people to choke; some well-known asphyxiants includes phosgene and chlorine. Vesicant or blister weapons cause blisters on the skin, sometimes after a delayed period of time: mustard gas is a classic vesicant. Many nations have also developed non-lethal chemicals weapons, designed to be used in crowd control, such as tear gas and some mild nerve agents, along with the so-called “Agent 15,” which causes total incapacitation for up to three days.
Many people feel that chemical warfare is extremely dangerous, because it does not distinguish between combatants and noncombatants, and it has the potential to contaminate air, water, and soil. The impacts of chemical weapons are also not pretty to see, and they have historically been abused by a number of nations; Saddam Hussein in Iraq, for example, tested chemical weapons on villages of Iraqi Kurds, causing mass deaths, and Germany notoriously used chemical agents to kill millions in death camps during the Second World War. Many people around the world are eager to see a unilateral ban on chemical weapons, accompanied with the destruction of all global stockpiles.