Chemical Warfare

Chemical warfare involves the use of natural or synthetic substances to incapacitate or kill an enemy or to deny them the use of resources such as agricultural products or screening foliage. The effects of the chemicals may last only a short time, or they may result in permanent damage and death. Most of the chemicals used are known to be toxic to humans or plant life. Other normally benign (mild) chemicals have also been intentionally misused in more broadly destructive anti-environmental actions, called ecocide, and as a crude method of causing mayhem and damaging an enemy's economic system. The deliberate dumping of large quantities of crude oil on the land or in the ocean is an example.

Chemical warfare dates back to the earliest use of weapons. Poisoned arrows and darts used for hunting were also used as weapons in intertribal conflicts (and primitive peoples still use them for these purposes today). In 431 B.C., the Spartans used burning sulfur and pitch to produce clouds of suffocating sulfur dioxide in their sieges against Athenian cities. When the Romans defeated the Carthaginians of North Africa in 146 B.C. during the last of a series of Punic Wars, they levelled the city of Carthage and treated the surrounding fields with salt to destroy the agricultural capability of the land, thereby preventing the rebuilding of the city.

The attraction of chemicals as agents of warfare was their ability to inflict mass casualties or damage to an enemy with only limited risk to the forces using the chemicals. Poisoning a town's water supply, for example, posed almost no threat to an attacking army, yet resulted in the death of thousands of the town's defenders. In many cases, the chemicals were also not detectable by the enemy until it was too late to take action.

Chemical agents can be classified into several general categories. Of those that attack humans, some, like tear gas, cause only temporary incapacitation. Other agents cause violent skin irritation and blistering, and may result in death. Some agents are poisonous and are absorbed into the bloodstream through the lungs or skin to kill the victim. Nerve agents attack the nervous system and kill by causing the body's vital functions to cease. Still others cause psychological reactions including disorientation and hallucinations. Chemical agents which attack vegetation include defoliants that kill plant leaves, herbicides that kill the entire plant, and soil sterilants that prevent the growth of new vegetation.