Chemical warfare is different from the use of conventional weapons or nuclear weapons because the destructive effects of chemical weapons are not primarily due to any explosive force. The offensive use of living organisms (such as anthrax) is considered to be biological warfare rather than chemical warfare. However, the use in war of toxic products produced by living organisms (e.g., toxins such as botulinum toxin, ricin, or saxitoxin) is considered as chemical warfare under the provisions of the Chemical Weapons Convention. Under this Convention, any toxic chemical, regardless of its origin, is considered as a chemical weapon unless it is used for purposes that are not prohibited (an important legal definition, known as the General Purpose Criterion).
Chemical warfare technology
|1910s||Lewisite||Chemical shells|| Gas mask|
Rosin oil clothing
|1920s||Projectiles w/ central bursters||CC-2 clothing|
|1930s||G-series nerve agents||Aircraft bombs|| Blister agent detectors|
Color change paper
|1940s|| Missile warheads|
| Protective ointment (mustard)|
Gas mask w/ Whetlerite
|1960s||V-series nerve agents||Aerodynamic||Gas mask w/ water supply||Nerve gas alarm|
|1980s||Binary munitions|| Improved gas masks|
(protection, fit, comfort)
|1990s||Novichok nerve agents|
Although crude chemical warfare has been employed in many parts of the world for thousands of years, "modern" chemical warfare began during World War I. Initially, only well-known commercially available chemicals and their variants were used. These included chlorine and phosgene gas. The methods of dispersing these agents during battle were relatively unrefined and inefficient.
Germany, the first side to employ chemical warfare on the battlefield, simply opened canisters of chlorine upwind of the opposing side and let the prevailing winds do the dissemination. Soon after, the French modified artillery munitions to contain phosgene – a much more effective method that became the principal means of delivery.
Since the development of modern chemical warfare in World War I, nations have pursued research and development on chemical weapons that falls into four major categories: new and more deadly agents; more efficient methods of delivering agents to the target (dissemination); more reliable means of defense against chemical weapons; and more sensitive and accurate means of detecting chemical agents.
Chemical warfare agents
A chemical used in warfare is called a chemical warfare agent (CWA), and is usually gaseous at room temperature or is a liquid that evaporates quickly. Such liquids are said to be volatile or have a high vapor pressure. The resulting fumes are toxic, hence the phrase "poison gas" used to describe a chemical weapon deployed in gaseous form. Many chemical agents are made volatile so they can be dispersed over a large region quickly.
The earliest target of chemical weapon agent research was not toxicity, but development of agents that can affect a target through the skin and clothing, rendering protective gas masks useless. In July 1917, the Germans first employed mustard gas, the first agent that circumvented gas masks. Mustard easily penetrates leather and fabric to inflict painful burns on the skin.
All chemical weapon agents are classified according to their persistency, a measure of the length of time that a chemical agent remains effective after dissemination. Chemical agents are classified as persistent or nonpersistent.
Agents classified as nonpersistent lose effectiveness after only a few minutes or hours. Purely gaseous agents such as chlorine are nonpersistent, as are highly volatile agents such as sarin and most other nerve agents. Tactically, nonpersistent agents are very useful against targets that are to be taken over and controlled very quickly. Generally speaking, nonpersistent agents present only an inhalation hazard.
By contrast, persistent agents tend to remain in the environment for as long as a week, complicating decontamination. Defense against persistent agents requires shielding for extended periods of time. Non-volatile liquid agents, such as blister agents and the oily VX nerve agent, do not easily evaporate into a gas, and therefore present primarily a contact hazard.
Classes of chemical warfare agents
Chemical warfare agents are organized into several categories according to the manner in which they affect the human body. The names and number of categories varies slightly from source to source, but in general, types of chemical warfare agents are as follows:
Template:Chemical warfare/CW table There are other chemicals used militarily that are not technically considered to be "chemical weapon agents," such as:
- Defoliants that destroy vegetation, but are not immediately toxic to human beings. (Agent Orange, for instance, used by the United States in Vietnam, contained dioxins and is known for its long-term cancer effects and for causing genetic damage leading to serious birth deformities.)
- Incendiary or explosive chemicals (such as napalm, extensively used by the United States in Vietnam, or dynamite) because their destructive effects are primarily due to fire or explosive force, and not direct chemical action.
- Viruses, bacteria, or other organisms, or their toxic products. Their use is classified as biological warfare.
Chemical weapon designations
Most chemical weapons are assigned a one- to three-letter "NATO weapon designation" in addition to, or in place of, a common name. Binary munitions, in which precursors for chemical weapon agents are automatically mixed in shell to produce the agent just prior to its use, are indicated by a "-2" following the agent's designation (for example, GB-2 and VX-2).
Some examples are given below:
|Pulmonary agents:||Incapacitating agents:|
|Lachrymatory agents:||Nerve agents:|
Chemical agent delivery
The most important factor in the effectiveness of chemical weapons is the efficiency of its delivery, or dissemination, to a target. The most common techniques include munitions (such as bombs, projectiles, warheads) that allow dissemination at a distance and spray tanks which disseminate from low-flying aircraft. Developments in the techniques of filling and storage of munitions have also been important.
Although there have been many advances in chemical weapon delivery since World War I, it is still difficult to achieve effective dispersion. The dissemination is highly dependent on atmospheric conditions because many chemical agents act in gaseous form. Thus, weather observations and forecasting are essential to optimize weapon delivery and reduce the risk of injuring friendly forces.
Dispersion is the simplest technique of delivering an agent to its target. It consists of placing the chemical agent upon or adjacent to a target immediately before dissemination, so that the material is most efficiently used.
World War I saw the earliest implementation of this technique, when German forces simply opened canisters of chlorine and allowed the wind to carry the gas across enemy lines. While simple and easy, this technique had numerous disadvantages. Delivery depended greatly on wind speed and direction. If the wind was fickle, as at Loos, the gas could blow back, causing friendly casualties. Gas clouds gave plenty of warning, allowing the enemy time to protect themselves, though many soldiers found the sight of a creeping gas cloud unnerving. Also gas clouds had limited penetration, capable only of affecting the front-line trenches before dissipating. Although it produced limited results in World War I, this technique shows how simple chemical weapon dissemination can be.
Shortly after this "open canister" dissemination, French forces developed a technique for delivery of phosgene in a non-explosive artillery shell. This technique overcame many of the risks of dealing with gas in cylinders. First, gas shells were independent of the wind and increased the effective range of gas, making any target within reach of guns vulnerable. Second, gas shells could be delivered without warning, especially the clear, nearly odorless phosgene — there are numerous accounts of gas shells, landing with a "plop" rather than exploding, being initially dismissed as dud high explosive or shrapnel shells, giving the gas time to work before the soldiers were alerted and took precautions.
The major drawback of artillery delivery was the difficulty of achieving a killing concentration. Each shell had a small gas payload and an area would have to be subjected to saturation bombardment to produce a cloud to match cylinder delivery.
Over the years, there were some refinements in this technique. In the 1950s and early 1960s, chemical artillery rockets contained a multitude of submunitions, so that a large number of small clouds of the chemical agent would form directly on the target.
Thermal dissemination is the use of explosives or pyrotechnics to deliver chemical agents. This technique, developed in the 1920s, was a major improvement over earlier dispersal techniques, in that it allowed significant quantities of an agent to be disseminated over a considerable distance. Thermal dissemination remains the principal method of disseminating chemical agents today.
Thermal dissemination devices, though common, are not particularly efficient. First, a percentage of the agent is lost by incineration in the initial blast and by being forced onto the ground. Second, the sizes of the particles vary greatly because explosive dissemination produces a mixture of liquid droplets of variable and difficult to control sizes.
The efficacy of thermal detonation is greatly limited by the flammability of some agents. For flammable aerosols, the cloud is sometimes totally or partially ignited by the disseminating explosion in a phenomenon called flashing. Explosively disseminated VX will ignite roughly one third of the time. Despite a great deal of study, flashing is still not fully understood, and a solution to the problem would be a major technological advance.
Despite the limitations of central bursters, most nations use this method in the early stages of chemical weapon development, in part because standard munitions can be adapted to carry the agents.
Aerodynamic dissemination is the non-explosive delivery of a chemical agent from an aircraft, allowing aerodynamic stress to disseminate the agent. This technique is the most recent major development in chemical agent dissemination, originating in the mid-1960s.
This technique eliminates many of the limitations of thermal dissemination by eliminating the flashing effect and theoretically allowing precise control of particle size. In actuality, the altitude of dissemination, wind direction and velocity, and the direction and velocity of the aircraft greatly influence particle size. There are other drawbacks as well; ideal deployment requires precise knowledge of aerodynamics and fluid dynamics, and because the agent must usually be dispersed within the boundary layer (less than 200–300 ft above the ground), it puts pilots at risk.
Significant research is still being applied toward this technique. For example, by modifying the properties of the liquid, its breakup when subjected to aerodynamic stress can be controlled and an idealized particle distribution achieved, even at supersonic speed. Additionally, advances in fluid dynamics, computer modeling, and weather forecasting allow an ideal direction, speed, and altitude to be calculated, such that weapon agent of a predetermined particle size can predictably and reliably hit a target.
Sociopolitical climate of chemical warfare
While the study of chemicals and their military uses was widespread in China, the use of toxic materials has historically been viewed with mixed emotions and some disdain in the West.
One of the earliest reactions to the use of chemical agents was from Rome. Struggling to defend themselves from the Roman legions, Germanic tribes poisoned the wells of their enemies, with Roman jurists having been recorded as declaring "armis bella non venenis geri", meaning "war is fought with weapons, not with poisons."
It is perhaps because of this view that in Europe before World War I, the use of poisonous chemicals in battle was typically the result of local initiative, and not the result of an active chemical weapons program. There are many reports of the isolated use of chemical agents in individual battles or sieges, but there was no true tradition of their use outside of incendiaries and smoke. Despite this tendency, there have been several attempts to initiate large-scale implementation of poison gas in several wars, but with the notable exception of World War I, the responsible authorities generally rejected the proposals for ethical reasons.
For example, in 1854 Lyon Playfair, a British chemist, proposed using a cyanide-filled artillery shell against enemy ships during the Crimean War. The British Ordnance Department rejected the proposal as "as bad a mode of warfare as poisoning the wells of the enemy."
This general concern over the use of poison gas manifested itself in 1899 at the Hague Conference with a proposal prohibiting shells filled with asphyxiating gas. The proposal was passed, despite a single dissenting vote from the United States. The American representative, Naval Capt. Alfred Thayer Mahan, justified voting against the measure on the grounds that "the inventiveness of Americans should not be restricted in the development of new weapons."
After extensive use of chemical weapons in World War I, the popular view of chemical weapons grew from distaste to disgust, such that their use had become the ultimate atrocity in the minds of most people at the time. So much so, in fact, that in 1925, sixteen of the world's major nations signed the Geneva Protocol, thereby pledging never to use gas biological methods of warfare again. Notably, in the United States, the Protocol languished in the Senate until 1975, when it was finally ratified.
Efforts to eradicate chemical weapons
- August 27 1874: The Brussels Declaration Concerning the Laws and Customs of War is signed, specifically forbidding the "employment of poison or poisoned weapons."
- September 4 1900: The Hague Conference, which includes a declaration banning the "use of projectiles the object of which is the diffusion of asphyxiating or deleterious gases," enters into force.
- February 6 1922: After World War I, the Washington Arms Conference Treaty prohibited the use of asphyxiating, poisonous or other gases. It was signed by the United States, Britain, Japan, France, and Italy, but France objected to other provisions in the treaty and it never went into effect.
- September 7 1929: The Geneva Protocol enters into force, prohibiting the use of poison gas and bacteriological methods of warfare. As of 2004, there are 132 signatory nations.
- May 1991: President George H.W. Bush unilaterally commits the United States to destroying all chemical weapons and to renounce the right to chemical weapon retaliation.
- April 29 1997: The Chemical Weapons Convention enters into force, augmenting the Geneva Protocol of 1925 by outlawing the production, stockpiling and use of chemical weapons.
Chemical weapon proliferation
Main article: Chemical weapon proliferation
Despite numerous efforts to reduce or eliminate them, some nations continue to research and/or stockpile chemical weapon agents. To the right is a summary of the nations that have either declared weapon stockpiles or are suspected of secretly stockpiling or possessing CW research programs. Notable examples include China and Israel.
According to the testimony of Assistant Secretary of State for Intelligence and Research Carl W. Ford before the Senate Committee on Foreign Relations, it is very probable that China has an advanced chemical warfare program, including research and development, production, and weaponization capabilities. Furthermore, there is considerable concern from the US regarding China's contact and sharing of chemical weapons expertise with other states of proliferation concern, including Syria and Iran.
As of December 2004, Israel has signed but not ratified the Chemical Weapons Convention, and according to the Russian Federation Foreign Intelligence Service, Israel has significant stores of chemical weapons of its own manufacture. It possesses a highly developed chemical and petrochemical industry, skilled specialists, and stocks of source material, and is capable of producing several nerve, blister and incapacitating agents. In 1974, in a hearing before the U.S. Senate Armed Services Committee, General Almquist stated that Israel had an offensive chemical weapons capability.
Chemical warfare in ancient and classical times
Chemical weapons have been used for millennia in the form of poisoned arrows, but evidence can be found for the existence of more advanced forms of chemical weapons in ancient and classical times.
A good example of early chemical warfare was the late Stone Age (10 000 BC) hunter-gatherer societies in Southern Africa, known as the San. They used poisoned arrows, tipping the wood, bone and stone tips of their arrows with poisons obtained from their natural environment. These poisons were mainly derived from scorpion or snake venom, but it is believed that some poisonous plants were also utilised. The arrow was fired into the target of choice, usually an antelope (the favourite being an Eland), with the hunter then tracking the doomed animal until the poison caused its collapse.
Dating from the 4th century BC, writings of the Mohist sect in China describe the use of bellows to pump smoke from burning balls of mustard and other toxic vegetables into tunnels being dug by a besieging army. Even older Chinese writings dating back to about 1000 BC contain hundreds of recipes for the production of poisonous or irritating smokes for use in war along with numerous accounts of their use. From these accounts we know of the arsenic-containing "soul-hunting fog", and the use of finely divided lime dispersed into the air to suppress a peasant revolt in AD 178.
The earliest recorded use of gas warfare in the West dates back to the 5th century BC, during the Peloponnesian War between Athens and Sparta. Spartan forces besieging an Athenian city placed a lighted mixture of wood, pitch, and sulfur under the walls hoping that the noxious smoke would incapacitate the Athenians, so that they would not be able to resist the assault that followed. Sparta wasn't alone in its use of unconventional tactics during these wars: Solon of Athens is said to have used hellebore roots to poison the water in an aqueduct leading from the Pleistrus River around 590 BC during the siege of Cirrha.
The rediscovery of chemical warfare
During the Renaissance, people again considered using chemical warfare. One of the earliest such references is from Leonardo da Vinci, who proposed a powder of sulfide of arsenic and verdigris in the 15th century:
- throw poison in the form of powder upon galleys. Chalk, fine sulfide of arsenic, and powdered verdegris may be thrown among enemy ships by means of small mangonels, and all those who, as they breathe, inhale the powder into their lungs will become asphyxiated.
It is unknown whether this powder was ever actually used.
In the 17th century during sieges, armies attempted to start fires by launching incendiary shells filled with sulphur, tallow, rosin, turpentine, saltpeter, and/or antimony. Even when fires were not started, the resulting smoke and fumes provided a considerable distraction. Although their primary function was never abandoned, a variety of fills for shells were developed to maximize the effects of the smoke.
In 1672, during his siege of the city of Groningen, Christoph Bernhard van Galen (the Bishop of Münster) employed several different explosive and incendiary devices, some of which had a fill that included belladonna, intended to produce toxic fumes. Just three years later, August 27 1675, the French and the Germans concluded the Strasbourg Agreement, which included an article banning the use of "perfidious and odious" toxic devices.
In 1854, Lyon Playfair, a British chemist, proposed a cacodyl cyanide artillery shell for use against enemy ships as way to solve the stalemate during the siege of Sevastopol. The proposal was backed by Admiral Thomas Cochrane of the Royal Navy. It was considered by the Prime Minister, Lord Palmerston, but the British Ordnance Department rejected the proposal as "as bad a mode of warfare as poisoning the wells of the enemy." Playfair’s response was used to justify chemical warfare into the next century:
- There was no sense in this objection. It is considered a legitimate mode of warfare to fill shells with molten metal which scatters among the enemy, and produced the most frightful modes of death. Why a poisonous vapor which would kill men without suffering is to be considered illegitimate warfare is incomprehensible. War is destruction, and the more destructive it can be made with the least suffering the sooner will be ended that barbarous method of protecting national rights. No doubt in time chemistry will be used to lessen the suffering of combatants, and even of criminals condemned to death.
Later, during the American Civil War, New York school teacher John Doughty proposed the offensive use of chlorine gas, delivered by filling a 10 inch (254 millimeter) artillery shell with 2 to 3 quarts (2 to 3 liters) of liquid chlorine, which could produce many cubic feet (a few cubic meters) of chlorine gas. Doughty’s plan was apparently never acted on, as it was probably presented to Brigadier General James W. Ripley, Chief of Ordnance, who was described as being congenitally immune to new ideas.
Chemical warfare in World War I
Main article: Use of poison gas in World War I
The French were the first to use chemical weapons during the First World War, using tear gas. The first full-scale deployment of chemical warfare agents was during World War I, originating in the Second Battle of Ypres, April 22 1915, when the Germans attacked France, Canadian and Algerian troops with chlorine gas. Deaths were light, though casualities relatively heavy. A total 50,965 tons of pulmonary, lachrymatory, and vesicant agents were deployed by both sides of the conflict, including chlorine, phosgene and mustard gas. Official figures declare about 1,176,500 non-fatal casualties and 85,000 fatalities directly caused by chemical warfare agents during the course of the war.
To this day unexploded WWI-era chemical ammunition is still frequently uncovered when the ground is dug in former battle or depot areas and continues to pose a threat to the civilian population in Belgium and France. The French and Belgian governments have had to launch special programs for treating discovered ammunition.
After the war, most of the unused German chemical warfare agents were dropped into the Baltic Sea. Over time, the salt water causes the shell casings to corrode, and mustard gas occasionally leaks from these containers and washes onto shore as a wax-like solid resembling amber. Even in this solidified form, the agent is active enough to cause severe contact burns to anybody handling it.
Chemical warfare in the interwar years
After World War I, the United States and many of the European powers attempted to take advantage of the opportunities that the war created by attempting to establish and hold colonies. During this interwar period, chemical agents were occasionally used to subdue populations and suppress rebellion.
Following the defeat of the Ottoman Empire in 1917, the Ottoman government collapsed completely, and the former empire was divided amongst the victorious powers in the Treaty of Sèvres. The British occupied Mesopotamia (present-day Iraq) and established a colonial government.
In 1920, the Arab and Kurdish people of Mesopotamia revolted against the British occupation, which cost the British dearly. As the Mesopotamian resistance gained strength, the British resorted to increasingly repressive measures, and Winston Churchill himself, in his role as Colonial Secretary, authorized the use of chemical agents, mostly mustard gas, on the Mesopotamian resistors. Mindful of the financial cost of suppressing the dissidents, Churchill was confident that chemical weapons could be inexpensively employed against the Mesopotamian tribes, saying "I do not understand this squeamishness about the use of gas. I am strongly in favour of using poison gas against uncivilised tribes."  Opposition to the use of gas and technical difficulties may have prevented the gas from being used in Mesopotamia (historians are currently divided on the issue). Chemical weapons had caused so much misery and revulsion in World War I that their use had become the ultimate atrocity in the minds of most people at the time. So much so, in fact, that in 1925, sixteen of the world's major nations signed the Geneva Protocol, thereby pledging never to use gas or bacteriological methods of warfare. While the United States signed the protocol, the Senate did not ratify it until 1975.
In 1935 Fascist Italy used mustard gas during the invasion of Ethiopia in the Second Italo-Abyssinian War. Ignoring the Geneva Protocol, which it signed seven years earlier, the Italian military dropped mustard gas in bombs, sprayed it from airplanes, and spread it in powdered form on the ground. 15,000 chemical casualties were reported, mostly from mustard gas.
Chemical warfare in World War II
During World War II, chemical warfare was revolutionized by Nazi Germany's accidental discovery of the nerve agents tabun, sarin and soman. The Nazis developed and manufactured large quantities of several agents, but chemical warfare was not extensively used by either side. Recovered Nazi documents suggest that German intelligence incorrectly thought that the Allies also knew of these compounds, interpreting their lack of mention in the Allies' scientific journals as evidence that information about them was being suppressed. Germany ultimately decided not to use the new nerve agents, fearing a potentially devastating Allied retaliatory nerve agent deployment.
William L. Shirer, in The Rise and Fall of the Third Reich, writes that the British high command considered the use of chemical weapons as a last-ditch defensive measure in the event of a Nazi invasion of Britain.
Although chemical weapons were not deployed on a large scale during World War II, there were some recorded uses of them by the Axis Powers, when retaliation wasn't feared:
- The Japanese used mustard gas and the recently-developed blister agent Lewisite against Chinese troops. During these attacks, the Japanese also employed biological warfare by intentionally spreading cholera, dysentery, typhoid, plague, and anthrax. As of 2005, 60 years after the end of the war, canisters that were abandoned by Japan in their hasty retreat are still being dug up in construction sites, causing many injuries and deaths.
- In 1944, the Grand Mufti of Jerusalem, Amin al-Husayni, the senior Islamic religious authority of the Palestinian Arabs and close ally of Adolf Hitler, sponsored an unsuccessful chemical warfare assault on the Jewish community in Palestine. Five parachutists were supplied with maps of Tel Aviv, canisters of a German–manufactured "fine white powder," and instructions from the Mufti to dump chemicals into the Tel Aviv water system. District police commander Fayiz Bey Idrissi later recalled, "The laboratory report stated that each container held enough poison to kill 25,000 people, and there were at least ten containers." 
- The Nazis used the insecticide Zyklon B, which contains hydrogen cyanide, to kill large numbers of victims in concentration camps such as Auschwitz and Majdanek during the Holocaust.
Chemical warfare during the Cold War
After World War II, the Allies recovered German artillery shells containing the three German nerve agents of the day (tabun, sarin, and soman), prompting further research into nerve agents by all of the former Allies. Although the threat of global thermonuclear annihilation was foremost in the minds of most during the Cold War, both the Soviet and Western governments put enormous resources into developing chemical and biological weapons.
Developments by the Western governments
Also in 1952, researchers in Porton Down, England, invented the VX nerve agent but soon abandoned the project. In 1958 the British government traded their VX technology with the United States in exchange for information on thermonuclear weapons; by 1961 the U.S. was producing large amounts of VX and performing its own nerve agent research. This research produced at least three more agents; the four agents (VE, VG, VM, VX) are collectively known as the "V-Series" class of nerve agents.
During the 1960s, the U.S. explored the use of anticholinergic deleriant incapacitating agents. One of these agents, assigned the weapon designation BZ, was allegedly used experimentally in the Vietnam War. These allegations inspired the 1990 fictional film Jacob's Ladder.
Between 1967 and 1968, the U.S. decided to dispose of obsolete chemical weapons in an operation called Operation CHASE, which stood for "cut holes and sink 'em." CHASE disposal operations also included several shiploads of conventional munitions. As the name implies, the weapons were put aboard old Liberty ships that were sunk at sea.
In 1969, 23 U.S. servicemen and one U.S. civilian stationed in Okinawa, Japan, were exposed to low levels of the nerve agent sarin while repainting the depots' buildings. The weapons had been kept secret from Japan, sparking a furor in that country and an international incident. These munitions were moved in 1971 to Johnston Atoll under Operation Red Hat.
A UN working group began work on chemical disarmament in 1980. On April 4, 1984, U.S. President Ronald Reagan called for an international ban on chemical weapons. U.S. President George H.W. Bush and Soviet Union leader Mikhail Gorbachev signed a bilateral treaty on June 1, 1990, to end chemical weapon production and start destroying each of their nation's stockpiles. The multilateral Chemical Weapons Convention (CWC) was signed in 1993 and came into effect in 1997.
Developments by the Soviet government
Due to the secrecy of the Soviet Union's government, very little information was available about the direction and progress of the Soviet chemical weapons until relatively recently. After the fall of the Soviet Union, Russian chemist Vil Mirzayanov published articles revealing illegal chemical weapons experimentation in Russia. In 1993, Mirzayanov was imprisoned and fired from his job at the State Research Institute of Organic Chemistry and Technology, where he had worked for 26 years. In March of 1994, after a major campaign by U.S. scientists on his behalf, Mirzayanov was released.
Among the information related by Vil Mirzayanov was the direction of Soviet research into the development of even more toxic nerve agents, which saw most of its success during the mid-1980s. Several highly toxic agents were developed during this period; the only unclassified information regarding these agents is that they are known in the open literature only as "Foliant" agents (named after the program under which they were developed) and by various code designations, such as A-230 and A-232.
According to Mirzayanov, the Soviets also developed agents that were safer to handle, leading to the development of the so-called binary weapons, in which precursors for the nerve agents are mixed in a munition to produce the agent just prior to its use. Because the precursors are generally significantly less hazardous than the agents themselves, this technique makes handling and transporting the munitions a great deal simpler. Additionally, precursors to the agents are usually much easier to stabilize than the agents themselves, so this technique also made it possible to increase the shelf life of the agents a great deal. During the 1980s and 1990s, binary versions of several Soviet agents were developed and are designated as "Novichok" agents (after the Russian word for "newcomer").
Chemical warfare in the Iran-Iraq War
The Iran-Iraq War began in 1980 when Iraq attacked Iran. Early in the conflict, Iraq began to employ mustard gas and tabun delivered by bombs dropped from airplanes; approximately 5% of all Iranian casualties are directly attributable to the use of these agents. Iraq and the U.S. government alleged that Iran was also using chemical weapons, but independent sources were unable to confirm these allegations.
About 100,000 Iranian soldiers were victims of Iraq's chemical attacks. Many were hit by mustard gas. The official estimate does not include the civilian population contaminated in bordering towns or the children and relatives of veterans, many of whom have developed blood, lung and skin complications, according to the Organization for Veterans. Nerve gas agents killed about 20,000 Iranian soldiers immediately, according to official reports. Of the 80,000 survivors, some 5,000 seek medical treatment regularly and about 1,000 are still hospitalized with severe, chronic conditions. 
Despite the removal of Saddam and his regime by Coalition forces, there is deep resentment and anger in Iran that it was Western companies based in West Germany, France, and the U.S. that helped Iraq develop its chemical weapons arsenal in the first place, and that the world did nothing to punish Iraq for its use of chemical weapons throughout the war.
Shortly before war ended in 1988, the Iraqi Kurdish village of Halabja was exposed to multiple chemical agents, killing about 5,000 of the town's 50,000 residents. After the incident, traces of mustard gas and the nerve agents sarin, tabun and VX were discovered. While it appears that Iraqi government forces are to blame, some debate continues over the question of whether Iraq was really the responsible party, and whether this was a deliberate or accidental act. (see Halabja poison gas attack)
During the Persian Gulf War in 1991, Coalition forces began a ground war in Iraq. Despite the fact that they did possess chemical weapons, Iraq did not use any chemical agents against coalition forces. The commander of the Allied Forces, Gen. H. Norman Schwarzkopf, suggested this may have been due to Iraqi fear of retaliation with nuclear weapons.
Chemical weapons and terrorism
For many terrorist organizations, chemical weapons might be considered an ideal choice for a mode of attack, if they are available: they are cheap, relatively accessible, and easy to transport. A skilled chemist can readily synthesize most chemical agents if the precursors are available.
Some political commentators dispute the practicality of chemical and biological weapons as tools of terrorism, however, stating that the effective use of such weapons is much more difficult than the use of conventional explosives, and that they are more useful in the fear that they generate. 
The earliest successful use of chemical agents in a non-combat setting was in 1946, motivated by a desire to obtain revenge on Germans for the Holocaust. Three members of a Jewish group calling themselves Dahm Y'Israel Nokeam ("Avenging Israel's Blood") hid in a bakery in the Stalag 13 prison camp near Nuremberg, Germany, where several thousand SS troops were being detained. The three applied an arsenic-containing mixture to loaves of bread, sickening more than 2,000 prisoners, of whom more than 200 required hospitalization.
In July of 1974, a group calling themselves the Aliens of America successfully firebombed the houses of a judge, two police commissioners, and one of the commissioner’s cars, burned down two apartment buildings, and bombed the Pan Am Terminal at Los Angeles International Airport, killing three people and injuring eight. The organization, which turned out to be a single resident alien named Muharem Kurbegovic, claimed to have developed and possessed a supply of sarin, as well as 4 unique nerve agents named AA1, AA2, AA3, and AA4S. Although no agents were found at the time he was arrested in August of 1974, he had reportedly acquired "all but one" of the ingredients required to produce a nerve agent. A search of his apartment turned up a variety of materials, including precursors for phosgene and a drum containing 25 pounds of sodium cyanide .
The first successful use of chemical agents by terrorists against a general civilian population was on March 20, 1995. Aum Shinrikyo, an apocalyptic group based in Japan that believed it necessary to destroy the planet, released sarin into the Tokyo subway system killing 12 and injuring over 5,000. The group had attempted biological and chemical attacks on at least 10 prior occasions, but managed to affect only cult members. The group did manage to successfully release sarin outside an apartment building in Matsumoto in June 1994; this use was directed at a few specific individuals living in the building and was not an attack on the general population.
In 2001, after carrying out the attacks in New York City on September 11, the organization Al Qaeda announced that they were attempting to acquire radiological, biological and chemical weapons. This threat was lent a great deal of credibility when a large archive of videotapes was obtained by the cable television network CNN in August of 2002 showing, among other things, the killing of three dogs by an apparent nerve agent.
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