Chemical and Biological Warfare, method of warfare in which toxic or incapacitating chemicals or biological agents are used to further the goals of the combatants. Until the 20th century such warfare was primarily limited to starting fires, poisoning wells, distributing smallpox-infected articles, and using smoke to confuse the enemy. Chemical Agents Gases such as tear gas, chlorine gas and phosgene (lung irritants), and mustard gas (causing burns) were first used in World War I to break the trench warfare stalemate. Flamethrowers were also tried but at first proved ineffective because of their short range. Technical improvements and the development of napalm (composed of napthenic and palmitin acids), a thickened gasoline that sticks to surfaces, led to the widespread use of flame weapons in World War II By the end of World War I, most European powers had integrated gas warfare capabilities into their armies at some level, and nerve gases such as sarin, small amounts of which cause paralysis or death, were developed in Germany between the two world wars. Despite the availability of gases, only Japan used the min China as World War II became global.
After World War II, knowledge of nerve-gas manufacture became widespread. The use of more deadly agents such as mustard gas and nerve gas has been generally condemned by most countries, but such weapons remain in the arsenals, and there is evidence that they were used by Iraq during its war with Iran in the 1980's. Various chemical compounds, such as Agent Orange, that alter the metabolism of plants and cause defoliation have been employed in modern jungle warfare to reduce the enemy's cover or deprive the civilian population of necessary food crops. Such chemicals, generally sprayed from the air, may contaminate water and fish as well; their long-lasting effect on the entire ecosystem makes them particularly devastating. Biological Warfare Several major nations have worked to some degree on the development of biological agents for use in warfare. Selected or adapted from pathogens causing various diseases that attack humans, domestic animals, or vital food crops, such agents include bacteria, fungi, and viruses or the toxins they produce.
The pathogens causing botulism, plague, hoof-and-mouth disease, and stem rust in wheat are among the many that could be directed against opposing armies or the civilian economies supporting them. Genetic engineering also offers the possibility of developing new virulent strains against which an opposing force could not be prepared in advance. Large-scale biological warfare has thus far remained theoretical, although in the 1980's it was learned that Japan used biological agents against the Chinese in the 1930's and early '40's. In the early 1980's, claims were also made that the Soviet Union, in Afghanistan, and Vietnam, in Laos and Kampuchea, were using fungal toxins in a form called "yellow rain " as biological weapons. The charges, however, were controversial and have not been proved. Dissemination and Protection The earliest method of disseminating chemical agents was simply to release them from pressurized containers, as the Germans did in World War I. This made the use of these weapons dependent on the wind; quite often the wind would change and bring the chemicals back onto friendly troops.
Thus, armies turned to better ways of projecting weapons, including mortars, artillery, rockets, aerial bombs, and aerial spray. Biological agents can also be disseminated by releasing insects or animals released in a target area. Whatever the means of dissemination, care must be taken to protect friendly forces and populations. Most nations are developing programs to detect lethal agents and decontaminate them. Efforts are also being made to develop offensive weapons that are less dangerous to store and use. The U.S. has an extensive program for the safe demilitarization of these weapons.
The chemical and biological weapons employed in nuclear or conventional war may also play a part in future guerrilla wars or sabotage actions. In such situations, inert toxic materials, such as dusts that are activated on contact with moist surfaces such as the lungs, might be surreptiously sprayed into city air from moving vehicles or from offshore vessels. The delivery of soluble toxins into urban water supplies in another possible tactic. Chemical and biological agents have possibilities for use in limited wars. The fact that it does not take a very sophisticated industrial base to produce lethal chemicals makes this a viable means of warfare for Third World countries. Use of chemical weapons by Iraq and Libya's chemical warfare capability in 1988 reinforce the danger that these weapons will spread.
The attraction of such weapons for terrorists is also a matter of great concern, since release of relatively small amounts of toxins in a water supply or into the air might cause a widespread catastrophe.