Chemical and Biological Weapons Summary

  • Last updated on November 11, 2022

Both chemical and biological weapons are considered “silent weapons of mass destruction.” The distinction between chemical and biological warfare is important because of differences in the scientific research and technological development that have influenced their use in war.

Nature and Use

Both chemical and biological weapons are considered “silent weapons of mass destruction.” The distinction between chemical and biological warfare is important because of differences in the scientific research and technological development that have influenced their use in war.Chemical weaponsBiological weaponsChemical weaponsBiological weapons

Chemical weapons are inanimate substances, usually gaseous or liquid, that can rapidly cause death or disability. Since antiquity, Poisonpoisons have been used as a fatal means of settling interpersonal conflict. Thus, knowledge of poisons must be considered the precursor to chemical weapons development. Poison science emerged as soon as humans developed a consistent technique for recognizing the detrimental properties of natural plant, animal, or mineral extracts. However, large-scale production of artificial chemicals required substantial technological advancements to facilitate both mass production and the safe deployment of dangerous chemicals against opponents in war. Chemical weapons have also been targeted against plants and animals for the purpose of debilitating agriculture and food resources; such chemicals are more adequately categorized by the familiar labels of herbicides and pesticides.

Biological weapons are preparations of live microorganisms that can rapidly cause debilitating disease and death in exposed populations. Pathogenic Bacteria;as weapons[weapons]Viruses as weaponsbacteria, viruses, and fungi with low infectious doses and high environmental survival rates are the primary components of biological weapons. Inanimate microbial products, such as fungal Fungal toxins as weaponstoxins, have also been developed as weapons, but these are better labeled as chemical weapons. By definition, biological weapons include pathogens targeted at domesticated plants and animals as a strategy for starving agricultural productivity. The use of biological weapons predates both the establishment of the germ theory of disease and the scientific understanding of the discrete nature of pathogens.

DevelopmentChemical Weapons

Three distinct classes of chemical weapons have existed throughout the developmental history of chemical warfare. The first, lethal Lethal agentsagents, cause death at various degrees of potency, depending on the biochemical properties of the components. The second, incapacitating Incapacitating agentsagents, are used to render soldiers incompetent for battle, and they generally do not kill more than 2 percent of exposed populations. The third, irritating Irritating agentsagents, such as lachrimators, or tear Tear gasesgases, make it difficult for soldiers to fight without wearing cumbersome protective gear, such as face masks and respirators. Irritating agents are generally nonlethal to all except individuals with preexposure conditions, such as asthma.

There have been at least five generations of chemical weapons since the 1500’s. The first generation predated the development of the large-scale industrial production facilities that facilitated the first concerted use of chemicals during World War I. Second-generation chemical weapons, mostly respiratory impairment gases, were developed for use during World War I. Third-generation agents, mostly nerve gases, were developed after World War I. Fourth-generation agents include psychoactive chemicals capable of inducing hallucinations in exposed individuals. Fifth-generation chemical weapons include new combinations of previously known chemical weapons, combinations of chemical and biological agents, or binary chemical weapons, which are endowed with innovative modes of delivery and action.

The first generation of chemical weapons in the modern era is traced to artist and inventor Leonardo da Vinci’s (1452-1519) description of shells loaded with very fine sulfur and arsenic dust. There is no evidence that Leonardo da Leonardo da VinciLeonardo da VinciVinci’s chemical weapon was actually used, so it is impossible to judge its effectiveness, but the description clearly marks the development of a weapon based on the coupling of specific chemicals with propelled contraptions. The second notable development after Leonardo da Vinci was the unsuccessful proposal developed between 1811 and 1855 by Thomas Cochrane, ThomasCochrane, ThomasCochrane (1775-1860), British naval officer and tenth earl of Dundonald, earl ofDundonald, earl ofDundonald, to use smoke from burning coal tar and carbon disulfide against French and Russian opponents.

The second generation of chemical weapons, developed toward the end of the nineteenth century, includes chlorine and phosgene. Chlorine was discovered and used as a bleaching agent before the end of the eighteenth century, and phosgene was discovered in 1812 as a product of the reaction between chlorine and carbon monoxide. Prohibition of poisonous gases was on the agenda of the first Hague Peace Hague Peace ConferencesConference, convened in 1899 by Czar Nicholas Nicholas IINicholas II (Russian czar)[Nicholas 02]II (1868-1918). Although detailed knowledge of the manufacture and use of chemical weapons was limited, the U.S. delegation to the 1899 conference took a lone position in refusing to ratify an agreement to abstain from the use of “asphyxiating or deleterious gases.” The second Hague Peace Hague Peace ConferencesConference, convened by President Theodore Roosevelt in 1907, expanded the prohibition to include “poison or poisoned weapons.” The Hague conference agreements remained in force until April 22, 1915, when Germany used chlorine tear gas in Ypres, Belgium, against Franco-Algerian soldiers during World War I.

Although hundreds of chemicals have been tested for military purposes since 1915, fewer than 5 percent of them proved to be of significance to weapons development. The Geneva Geneva ProtocolsProtocol, signed by several countries on June 17, 1925, for the “prohibition of the use in war of asphyxiating, poisonous, or other gases and of bacteriological methods of warfare,” did little to deter the development of new chemical weapons or the improvement of delivery of old ones. Among the chemicals mentioned were organophosphorus nerve agents, which constitute the third generation of chemical weapons. Nerve Nerve agentsGas;nerve gasgases inhibit certain cholinesterase enzymes that affect nerve function and lead to excessive sweating, uncontrollable vomiting and defecation, and, finally, death from respiratory paralysis or asphyxia. Tabun (nerve gas)Tabun and Sarin gassarin were discovered by chance in 1936 and 1938, respectively, by the German scientist Gerhard Schrader, GerhardSchrader, GerhardSchrader (1903-1991), who was conducting research on Pesticidespesticides for the company I. G. I. G. FarbenfabrikenFarbenfabriken. Tabun persists in the environment, whereas sarin dissipates rather quickly. Tabun was the first nerve gas to be manufactured on a large scale, and it was stockpiled by Germany during World War II.

British soldiers wear gas masks to protect against respiratory-impairment gases as they wield a Vickers machine gun at the Battle of the Somme, July, 1916.

(Hulton Archive/Getty Images)

Nazi Germany’s use of lethal gas and other countries’ capacity to develop and manufacture chemical weapons led to a post-World War II emphasis on defense strategies against chemical weapons. Sophisticated military reconnaissance strategies for chemical weapons included automatic detection systems such as the Nerve Agent Immobilized Enzyme Alarm Nerve Agent Immobilized Enzyme Alarm DetectorDetector, which responds to small concentrations of nerve agents and cyanide. Similarly, equipment for personal and collective protection was rapidly developed, as were methods of environmental decontamination and medical treatment for exposed individuals.

Psychoactive Psychoactive chemicalschemicals, the fourth generation of chemical weapons, were developed between 1959 and 1965. The incentive was to calm the growing public distaste for the use of lethal chemicals. The best-known psychoactive chemical weapon is quinuclidinyl Quinuclidinyl benzilatebenzilate, known as BZ, a relative of the psychedelic drug lysergic acid Lysergic acid diethylamidediethylamide (LSD), which induces altered states of consciousness. In the United States, BZ was advertised in a publicity campaign known as Operation Blue Operation Blue Skies (Cold War)Skies, intended to reduce public anxiety about chemical warfare. The campaign promoted the drug as one that caused only temporary insanity and paralysis of the will to fight, thereby pacifying violent individuals. However, BZ was too expensive for large-scale manufacture, and the dose required for effect was unpredictable.

U.N. workers prepare Iraqi rockets, reportedly filled with sarin, a chemical weapon that affects nerve function, for destruction after the Persian Gulf War.

(AP/World Wide Photos)

Binary Binary weaponsweapons are representatives of the fifth generation of chemical weapons. Binary artillery projectiles were developed in the United States in response to growing tensions during the Cold Cold War (1945-1991);binary weaponsWar era (1945-1991) and to the apparent superiority of Soviet chemical weapons. Between 1978 and 1985, research was intensified on the development of binary Projectiles;binaryprojectiles designed for deployment in war crises. In 1987 the United States designed a binary system to increase the quantity of sarin that could be transported to areas where it was required. The two chemicals that react to form sarin would be stored and shipped separately and then brought together at the gun site, where mixing and deployment could proceed rapidly and safely.

Biological Weapons

The development of modern biological weapons occurred in four distinct phases based on scientific advancements in the understanding of infectious diseases and the manipulation of microorganisms and ensuing technological innovations. The “contagion and miasma” phase (300 b.c.e.-1763 c.e.) occurred before the causative microbial origin of diseases was fully understood. During this period biological weapons consisted of attempts to contaminate the environment with actual bodies of diseased animals or humans. The second phase of biological weapons development (1763-1925) was marked by the use of Fomitesfomites, or materials that have been in contact with diseased persons, used as weapons. The third, the “culture and stockpile” phase, involved the development of technical capacity to cultivate large quantities of microorganisms and vaccines. This period lasted from 1925 to 1969. The fourth phase, beginning in 1969, no less than a biological-science revolution, is marked by the development of genetic engineering, or recombinant DNA, facilitating the construction of organisms with new pathogenic traits.

Until the seventeenth century diseased corpses and carcasses were used as biological weapons by the Greeks, Romans, and Persians to contaminate drinking Water contaminationwater and spread disease. Modern biological weapon development was initiated in 1763 when American military officers contemplated the use of smallpox-contaminated Smallpox;contaminated blanketsblankets against Native Americans in the French and Indian French and Indian War (1754-1763)War; however, there is no concrete evidence that the proposal was implemented.

The discoveries of French chemist and microbiologist Louis Pasteur, LouisPasteur, LouisPasteur (1822-1895) greatly influenced the trajectory of biological weapons development in the nineteenth and twentieth centuries. During World War I, Germany allegedly used the plague and cholera against opponents in Russia and Italy, respectively. Anton Dilger, AntonDilger, AntonDilger (1884-1918), a German secret agent working in the United States, is credited with the development of batch culture techniques for producing large quantities of Bacillus anthracis, the causative agent of Anthrax anthrax, and Pseudomonas mallei, the causative agent of Glanders glanders. Germany used these biological weapons to target horses and cattle in 1916 and was accused of dropping Plague plague bombs and inoculating toys and candy in Romania.

The Geneva Geneva ProtocolsProtocol of 1925 condemned the use of biological and chemical weapons but did not restrict their development, research, or stockpiling. The U.S. Congress did not ratify the Geneva Protocol until 1975 and did so only after several reservations were added to the provisions relating to the use of banned agents against nonsignatory nations or violators of the protocol. The first dedicated biological warfare research program was established by the Soviet Union in 1929. Japan and the United Kingdom initiated similar programs in 1934, and the U.S. Army joined the race in 1941. Japan;biological weaponsJapan’s biological weapons development program was particularly notable, because it involved tests and experimentation on human subjects.

During the Cold War period, intensive research and development on biological weapons was made. In 1943 the United States had established Fort Fort DetrickDetrick in northern Maryland as the main center of biological weapons research. Canada, the United Kingdom, and the United States collaborated on modeling biological weapons dissemination, including the release of pathogens in the Caribbean Sea and open-air experiments in urban centers within the United States. By 1950 experiments on the aerial dispersal of pathogens had been conducted with Serratia marcescens and Bacillus globigii in San Francisco, California, and Norfolk, Virginia. Urban locale experiments to aid the development of biological weapons were conducted in the transportation subways of New York City in the 1960’s. Nevertheless, the U.S. military concluded around 1969 that the potential usefulness of biological weapons was severely limited under battlefield conditions. This policy reversal led to the relaxation of international research and development programs on biological warfare. Consequently, there was widespread support for the 1972 Biological Weapons Biological Weapons Convention (1972) Convention on the “prohibition of the development, production and stockpiling of bacteriological (biological) and toxin weapons and on their destruction.”

The fourth phase of biological weapons development effectively began in 1969, with the invention of recombinant DNA techniques. These new Biotechnology and weaponsGenetic engineering of weaponsbiotechnology techniques created endless possibilities of recombining pathogen attributes from a variety of sources to produce more potent biological weapons than those isolated directly from nature. An outbreak of anthrax in Sverdlovsk, in the Soviet Union, killed at least sixty-four people in 1979. By 1982 several reports had been published in Western news media on the use of genetic engineering in the Soviet biological weapons development program. In 1988 the potential impact of U.S. biological weapons testing in Utah’s Dugway Proving Dugway Proving Grounds (Utah)Grounds was publicized. During the 1980’s and 1990’s, attention became focused on the relatively easy access that developing nations have to genetic engineering techniques for producing potent pathogens. Moreover, belief in the boundless potentials of recombinant DNA created the fear that it is virtually impossible to develop effective defense technology against biological weapons.

There were allegations that biological weapons were used during the Iran-Iraq War Iran-Iraq War (1980-1988)[Iran Iraq War](1980-1988). In 1998 the defunct apartheid regime of South Africa was accused of developing and using biological weapons. The involvement of developing countries worldwide, and Africa;biological weaponsAfrican countries in particular, in the development and use of biological weapons is particularly troublesome because the continent harbors some of the most deadly pathogens, including viruses such as the Ebola Ebola virusvirus. The increasing incidence of antibiotic-resistant strains of pathogenic Bacteria;antibiotic-resistantbacteria has been a relatively recent cause for alarm in the development of biological weapons. Antibiotic resistance traits can evolve naturally in microbial populations, but the dangerous traits can also be manipulated to render the defense strategies based on known medications ineffective.Chemical weaponsBiological weapons

Books and Articles
  • Bowman, Steve. Biological Weapons: A Primer. Huntington, N.Y.: Novinka Books, 2001.
  • Cirincione, Joseph. Deadly Arsenals: Nuclear, Biological, and Chemical Threats. 2d ed. Washington, D.C.: Carnegie Endowment for International Peace, 2005.
  • Cole, Leonard A. The Eleventh Plague: The Politics of Biological and Chemical Warfare. New York: W. H. Freeman, 1997.
  • Croddy, Eric, Clarisa Perez-Armendariz, and John Hart. Chemical and Biological Warfare: A Comprehensive Survey for the Concerned Citizen. New York: Copernicus Books, 2002.
  • Dando, Malcolm. Biological Warfare in the Twenty-first Century: Biotechnology and the Proliferation of Biological Weapons. London: Brassey’s, 1994.
  • Drell, Sidney D., Abraham D. Sofaer, and George D. Wilson, eds. The New Terror: Facing the Threat of Biological and Chemical Weapons. Stanford, Calif.: Hoover Institution Press, 1999.
  • Harris, Robert, and Jeremy Paxman. A Higher Form of Killing: The Secret History of Chemical and Biological Warfare. New York: Random House Trade Paperbacks, 2002.
  • Langford, Roland E. Introduction to Weapons of Mass Destruction: Radiological, Chemical, and Biological. Hoboken, N.J.: Wiley-Interscience, 2004.
  • Spiers, Edward M. Chemical and Biological Weapons: A Study of Proliferation. New York: St. Martin’s Press, 1994.
  • Tucker, Jonathan B. War of Nerves: Chemical Warfare from World War I to Al-Qaeda. New York: Pantheon Books, 2006.
  • _______, ed. Toxic Terror: Assessing Terrorist Use of Chemical and Biological Weapons. Cambridge, Mass.: MIT Press, 2000.
  • Wheelis, Mark, Lajos Rózsa, and Malcolm Dando, eds. Deadly Cultures: Biological Weapons Since 1945. Cambridge, Mass.: Harvard University Press, 2006.
  • Wright, Susan, ed. Preventing a Biological Arms Race. Cambridge, Mass.: MIT Press, 1990.
Films and Other Media
  • Plague War. Documentary. Public Broadcasting Service/WGBH, 1998.
  • Spying on Saddam: Investigation of the UN’s Dramatic, Thwarted Effort to Uncover Iraq’s Chemical, Biological, and Nuclear Weapons. Documentary. Public Broadcasting Service/WGBH, 1999.
  • Terrorism: Biological Weapons. Documentary and information guide. Emergency Film Group/Detrick Lawrence Corporation, 2000.
  • Terrorism: Chemical Weapons. Documentary and information guide. Emergency Film Group/Detrick Lawrence Corporation, 2000.
  • Toxic Agents: Viruses and Chemical and Biological Warfare. Documentary. History Channel, 2008.

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