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Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical (warfare or weapons). None of these fall under the term conventional weapons which are primarily effective due to their destructive potential. Chemical warfare does not depend upon explosive force to achieve an objective. Rather it depends upon the unique properties of the chemical agent weaponized. A lethal agent is designed to injure or incapacitate the enemy, or deny unhindered use of a particular area of terrain. Defoliants are used to quickly kill vegetation and deny its use for cover and concealment. It can also be used against agriculture and livestock to promote hunger and starvation. With proper protective equipment, training, and decontamination measures, the primary effects of chemical weapons can be overcome. Many nations possess vast stockpiles of weaponized agents in preparation for wartime use. The threat and the perceived threat have become strategic tools in planning both measures, and counter–measures.

Definition[link]

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 biological warfare rather than chemical warfare; however, the use of nonliving toxic products produced by living organisms (e.g. toxins such as botulinum toxin, ricin, and saxitoxin) is considered chemical warfare under the provisions of the Chemical Weapons Convention (CWC). Under this Convention, any toxic chemical, regardless of its origin, is considered a chemical weapon unless it is used for purposes that are not prohibited (an important legal definition known as the General Purpose Criterion).^[1]

About 70 different chemicals have been used or stockpiled as chemical warfare agents during the 20th century. The entire class known as Lethal Unitary Chemical Agents and Munitions have been scheduled for elimination by the CWC.^[2]

Under the Convention, chemicals that are toxic enough to be used as chemical weapons, or that may be used to manufacture such chemicals, are divided into three groups according to their purpose and treatment:

• Schedule 1 – Have few, if any, legitimate uses. These may only be produced or used for research, medical, pharmaceutical or protective purposes (i.e. testing of chemical weapons sensors and protective clothing). Examples include nerve agents, ricin, lewisite and mustard gas. Any production over 100 g must be notified to the OPCW and a country can have a stockpile of no more than one tonne of these chemicals.
• Schedule 2 – Have no large-scale industrial uses, but may have legitimate small-scale uses. Examples include dimethyl methylphosphonate, a precursor to sarin but which is also used as a flame retardant and Thiodiglycol which is a precursor chemical used in the manufacture of mustard gas but is also widely used as a solvent in inks.
• Schedule 3 – Have legitimate large-scale industrial uses. Examples include phosgene and chloropicrin. Both have been used as chemical weapons but phosgene is an important precursor in the manufacture of plastics and chloropicrin is used as a fumigant. The OPCW must be notified of, and may inspect, any plant producing more than 30 tonnes per year.

Technology[link]

A Swedish Army soldier wearing a chemical agent protective suit (C-vätskeskydd) and protection mask (skyddsmask 90).

Although crude chemical warfare has been employed in many parts of the world for thousands of years,^[3] "modern" chemical warfare began during World War I - see Poison gas in World War I.

Initially, only well-known commercially available chemicals and their variants were used. These included chlorine and phosgene gas. The methods used to disperse these agents during battle were relatively unrefined and inefficient. Even so, casualties could be heavy, due to the mainly static troop positions which were characteristic features of trench warfare.

Germany, the first side to employ chemical warfare on the battlefield,^[4] 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.^[5]

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[link]

A chemical used in warfare is called a chemical warfare agent (CWA). About 70 different chemicals have been used or stockpiled as chemical warfare agents during the 20th and 21st-centuries. These agents may be in liquid, gas or solid form. Liquid agents are generally designed to evaporate quickly; such liquids are said to be volatile or have a high vapor pressure. Many chemical agents are made volatile so they can be dispersed over a large region quickly.

The earliest target of chemical warfare 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 employed mustard gas. Mustard gas easily penetrates leather and fabric to inflict painful burns on the skin.

Chemical warfare agents are divided into lethal and incapacitating categories. A substance is classified as incapacitating if less than 1/100 of the lethal dose causes incapacitation, e.g., through nausea or visual problems. The distinction between lethal and incapacitating substances is not fixed, but relies on a statistical average called the LD₅₀.

Persistency[link]

One way to classify chemical warfare agents is 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 or even only a few seconds. 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.

Apart from the agent used, the delivery mode is very important. To achieve a nonpersistent deployment, the agent is dispersed into very small droplets comparable with the mist produced by an aerosol can. In this form not only the gaseous part of the agent (around 50%) but also the fine aerosol can be inhaled or taken up by the skin.

Modern doctrine requires very high concentrations almost instantly in order to be effective (one breath should contain a lethal dose of the agent). To achieve this, the primary weapons used would be rocket artillery or bombs and large ballistic missiles with cluster warheads. The contamination in the target area is only low or not existent and after four hours sarin or similar agents are not detectable anymore.

By contrast, persistent agents tend to remain in the environment for as long as several weeks, 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.

The droplet size used for persistent delivery goes up to 1 mm increasing the falling speed and therefore about 80% of the deployed agent reaches the ground, resulting in heavy contamination. This implies, that persistent deployment does not aim at annihilating the enemy but to constrain him.

Possible targets include enemy flank positions (averting possible counter attacks), artillery regiments, commando posts or supply lines. Possible weapons to be used are wide spread, because the fast delivery of high amounts is not a critical factor.

A special form of persistent agents are thickened agents. These comprise a common agent mixed with thickeners to provide gelatinous, sticky agents. Primary targets for this kind of use include airfields, due to the increased persistency and difficulty of decontaminating affected areas.

Classes[link]

Chemical weapons are inert agents that come in four categories: choking, blister, blood and nerve.^[6] The 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:

There are other chemicals used militarily that are not scheduled by the Chemical Weapons Convention, and thus are not controlled under the CWC treaties. These include:

• Defoliants that destroy vegetation, but are not immediately toxic to human beings. Some batches of Agent Orange, for instance, used by the United States in Vietnam, contained dioxins as manufacturing impurities. Dioxins, rather than Agent Orange itself, have 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. Their use is classified as biological warfare. Toxins produced by living organisms are considered chemical weapons, although the boundary is blurry. Toxins are covered by the Biological Weapons Convention.

Designations[link]

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 warfare 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:

Delivery[link]

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[link]

Dispersion of chlorine in World War I

Dispersion is placing the chemical agent upon or adjacent to a target immediately before dissemination, so that the material is most efficiently used. Dispersion is the simplest technique of delivering an agent to its target. The most common techniques are munitions, bombs, projectiles, spray tanks and warheads.

World War I saw the earliest implementation of this technique. The actual first chemical ammunition was the French 26 mm cartouche suffocante rifle grenade, fired from a flare carbine. It contained 35g of the tear-producer ethylbromacetate, and was used in autumn 1914 – with little effect on the Germans.

The Germans on the other hand tried to increase the effect of 10.5 cm shrapnel shells by adding an irritant – dianisidine chlorosulfonate. Its use went unnoticed by the British when it was used against them at Neuve Chapelle in October 1914. Hans Tappen, a chemist in the Heavy Artillery Department of the War Ministry, suggested to his brother, the Chief of the Operations Branch at German General Headquarters, the use of the tear-gases benzyl bromide or xylyl bromide.

Shells were tested successfully at the Wahn artillery range near Cologne on 9 January 1915, and an order was placed for 15 cm howitzer shells, designated ‘T-shells’ after Tappen. A shortage of shells limited the first use against the Russians at Bolimów on 31 January 1915; the liquid failed to vaporize in the cold weather, and again the experiment went unnoticed by the Allies.

The first effective use were when the German forces at the Second Battle of Ypres simply opened cylinders of chlorine and allowed the wind to carry the gas across enemy lines. While simple, this technique had numerous disadvantages. Moving large numbers of heavy gas cylinders to the front-line positions from where the gas would be released was a lengthy and difficult logistical task.

Aerial photograph of a German gas attack on Russian forces circa 1916

Stockpiles of cylinders had to be stored at the front line, posing a great risk if hit by artillery shells. Gas 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. This made the gas doubly effective, as, in addition to damaging the enemy physically, it also had a psychological effect on the intended victims.

Another disadvantage was that 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. A British solution to the problem was the Livens Projector. This was effectively a large-bore mortar, dug into the ground that used the gas cylinders themselves as projectiles - firing a 14 kg cylinder up to 1500 m. This combined the gas volume of cylinders with the range of artillery.

Over the years, there were some refinements in this technique. In the 1950s and early 1960s, chemical artillery rockets and cluster bombs 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[link]

An American-made MC-1 gas bomb

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.

Most thermal dissemination devices consist of a bomb or projectile shell that contains a chemical agent and a central "burster" charge; when the burster detonates, the agent is expelled laterally.

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.

Soviet chemical weapons canisters from a stockpile in Albania

Aerodynamic dissemination[link]

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 warfare agent of a predetermined particle size can predictably and reliably hit a target.

Protection against chemical warfare[link]

Israel Defense Forces "Yanshuf" battalion soldiers at chemical warfare defense exercise

Ideal protection begins with nonproliferation treaties such as the Chemical Weapons Convention, and detecting, very early, the signatures of someone building a chemical weapons capability. These include a wide range of intelligence disciplines, such as economic analysis of exports of dual-use chemicals and equipment, human intelligence (HUMINT) such as diplomatic, refugee, and agent reports; photography from satellites, aircraft and drones (IMINT); examination of captured equipment (TECHINT); communications intercepts (COMINT); and detection of chemical manufacturing and chemical agents themselves (MASINT).

If all the preventive measures fail and there is a clear and present danger, then there is a need for detection of chemical attacks,^[7] collective protection,^[8][9][10] and decontamination. Since industrial accidents can cause dangerous chemical releases (e.g., the Bhopal disaster), these activities are things that civilian, as well as military, organizations must be prepared to carry out. In civilian situations in developed countries, these are duties of HAZMAT organizations, which most commonly are part of fire departments.

Detection has been referred to above, as a technical MASINT discipline; specific military procedures, which are usually the model for civilian procedures, depend on the equipment, expertise, and personnel available. When chemical agents are detected, an alarm needs to sound, with specific warnings over emergency broadcasts and the like. There may be a warning to expect an attack.

If, for example, the captain of a US Navy ship believes there is a serious threat of chemical, biological, or radiological attack, the crew may be ordered to set Circle William, which means closing all openings to outside air, running breathing air through filters, and possibly starting a system that continually washes down the exterior surfaces. Civilian authorities dealing with an attack or a toxic chemical accident will invoke the Incident Command System, or local equivalent, to coordinate defensive measures.^[10]

Individual protection starts with a gas mask and, depending on the nature of the threat, through various levels of protective clothing up to a complete chemical-resistant suit with a self-contained air supply. The US military defines various levels of MOPP (mission-oriented protective posture) from mask to full chemical resistant suits; Hazmat suits are the civilian equivalent, but go farther to include a fully independent air supply, rather than the filters of a gas mask.

Collective protection allows continued functioning of groups of people in buildings or shelters, the latter which may be fixed, mobile, or improvised. With ordinary buildings, this may be as basic as plastic sheeting and tape, although if the protection needs to be continued for any appreciable length of time, there will need to be an air supply, typically a scaled-up version of a gas mask.^[9][10]

Members of the Ukrainian Army’s 19th Nuclear, Biological and Chemical Battalion practice decontamination drill, at Camp Arifjan, Kuwait

Decontamination[link]

Decontamination varies with the particular chemical agent used. Some nonpersistent agents, such as most pulmonary agents such as chlorine and phosgene, blood gases, and nonpersistent nerve gases (e.g., GB) will dissipate from open areas, although powerful exhaust fans may be needed to clear out buildings where they have accumulated.

In some cases, it might be necessary to neutralize them chemically, as with ammonia as a neutralizer for hydrogen cyanide or chlorine. Riot control agents such as CS will dissipate in an open area, but things contaminated with CS powder need to be aired out, washed by people wearing protective gear, or safely discarded.

Mass decontamination is a less common requirement for people than equipment, since people may be immediately affected and treatment is the action required. It is a requirement when people have been contaminated with persistent agents. Treatment and decontamination may need to be simultaneous, with the medical personnel protecting themselves so they can function.^[11]

There may need to be immediate intervention to prevent death, such as injection of atropine for nerve agents. Decontamination is especially important for people contaminated with persistent agents; many of the fatalities after the explosion of a WWII US ammunition ship carrying mustard gas, in the harbor of Bari, Italy, after a German bombing on 2 December 1943, came when rescue workers, not knowing of the contamination, bundled cold, wet seamen in tight-fitting blankets.

For decontaminating equipment and buildings exposed to persistent agents, such as blister agents, VX or other agents made persistent by mixing with a thickener, special equipment and materials might be needed. Some type of neutralizing agent will be needed; e.g. in the form of a spraying device with neutralizing agents such as Chlorine, Fichlor, strong alkaline solutions or enzymes. In other cases, a specific chemical decontaminant will be required.^[10]

Sociopolitical climate[link]

The study of chemicals and their military uses was widespread in China and India. The use of toxic materials has historically been viewed with mixed emotions and moral qualms in the West. The practical and ethical problems surrounding poison warfare appeared in ancient Greek myths about Hercules' invention of poison arrows and Odysseus's use of toxic projectiles. There are many instances of the use of chemical weapons in battles documented in Greek and Roman historical texts; the earliest example was the deliberate poisoning of Kirrha's water supply with hellebore in the First Sacred War, Greece, about 590 BC.^[12]

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." Yet the Romans themselves resorted to poisoning wells of besieged cities in Anatolia in the 2nd century BCE.^[13]

Before 1915 the use of poisonous chemicals in battle was typically the result of local initiative, and not the result of an active government 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 (later 1st Baron Playfair, GCB, PC, FRS (1 May 1818 – 29 May 1898), a British chemist, proposed using a cacodyl 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."

Efforts to eradicate chemical weapons[link]

• 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.

Chemical weapon proliferation[link]

Despite numerous efforts to reduce or eliminate them, some nations continue to research and/or stockpile chemical warfare 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 United States and Russia.

Former US Vice President Dick Cheney opposed the signing ratification of a treaty banning the use chemical weapons, a recently unearthed letter shows. In a letter dated April 8, 1997, then Halliburton-CEO Cheney told Sen. Jesse Helms, the chairman of the Senate Foreign Relations Committee, that it would be a mistake for America to join the Convention. "Those nations most likely to comply with the Chemical Weapons Convention are not likely to ever constitute a military threat to the United States. The governments we should be concerned about are likely to cheat on the CWC, even if they do participate," reads the letter,^[14] published by the Federation of American Scientists.

The CWC was ratified by the Senate that same month. Since then, Albania, Libya, Russia, the United States, and India have declared over 71,000 metric tons of chemical weapon stockpiles, and destroyed about a third of them. Under the terms of the agreement, the United States and Russia are supposed to eliminate the rest of their supplies of chemical weapons by 2012. But that looks unlikely– the U.S. government estimates remaining stocks will be destroyed by 2017.^{[citation needed]}

History[link]

Ancient to medieval times[link]

Chemical weapons have been used for millennia in the form of poisoned spears and 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.^{[citation needed]} 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 utilized. 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.

Ancient Greek myths about Hercules poisoning his arrows with the venom of the Hydra Monster are the earliest references to toxic weapons in western literature. Homer's epics, the Iliad and the Odyssey, allude to poisoned arrows used by both sides in the legendary Trojan War (Bronze Age Greece).^[13]

Textual and Literary Evidence[link]

Some of the earliest surviving references to toxic warfare appear in the Indian epics Ramayana and Mahabharata.^[15]

The "Laws of Manu," a Hindu treatise on statecraft (c. 400 BC) forbids the use of poison and fire arrows, but advises poisoning food and water. Kautilya's "Arthashastra," a statecraft manual of the same era, contains hundreds of recipes for creating poison weapons, toxic smokes, and other chemical weapons. Ancient Greek historians recount that Alexander the Great encountered poison arrows and fire incendiaries in India at Indus Basin in the 4th century BC.^[13]

Sun Tzu's "Art of War" (c. 200 BC) advises the use of fire weapons. In the 2nd 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. Other Chinese writings dating around the same period 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 was not alone in its use of unconventional tactics in ancient Greece: Solon of Athens is said to have used hellebore roots to poison the water in an aqueduct leading from the River Pleistos around 590 BC during the siege of Kirrha.^[13]

Polish chronicler Jan Długosz mentions usage of poisonous gas by the Mongol army in 1241 in the Battle of Legnica. However, his report is not firsthand, as he was born in the 15th century. According to Mukhamedzhan Tynyshpaev, Długosz's chronicle is unclear as to what kind of device or gas was used, giving only a description of a noxious smell. Rather, he suggests, this is a repeat of the trope of the Mongols' bad smell as an excuse for their annihilation of European defenders.^[16]

Historian and philosopher David Hume, in his history of England, recounts how in the reign of Henry III (r.1216 - 1272) the English Navy destroyed an invading French fleet, by blinding the enemy fleet with "quicklime," the old name for calcium oxide. D’Albiney employed a stratagem against them, which is said to have contributed to the victory: Having gained the wind of the French, he came down upon them with violence; and throwing in their faces a great quantity of quicklime, which he purposely carried on board, he so blinded them, that they were disabled from defending themselves.^[17]

Archaeological Evidence[link]

There is archaeological evidence that the Sasanians deployed chemical weapons against the Roman army in 3rd century AD/CE. Research carried out on the collapsed tunnels at Dura-Europos in Syria suggests that the Iranians used bitumen and sulfur crystals to get it burning. When ignited, the materials gave off dense clouds of choking gases which killed 20 Roman soldiers in a matter of 2 minutes.^[18]

Rediscovery[link]

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2010)

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 late 15th century, Spanish conquistadors encountered a rudimentary type of chemical warfare on the island of Hispaniola. The Taíno threw gourds filled with ashes and ground hot peppers at the Spaniards to create a blinding smoke screen before launching their attack.^[19]

In the 17th century during sieges, armies attempted to start fires by launching incendiary shells filled with sulfur, 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 Deadly Nightshade, 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.^{[citation needed]}

In June 1845, British troops attacking Maori trenches and bunkers at Ohaeawai in New Zealand fired shells containing an unknown type of poison gas from their cannon and mortars. The Maori withstood the bombardment and won the battle.^{[citation needed]}

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:^{[citation needed]}

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^{[citation needed]} presented to Brigadier General James Wolfe Ripley, Chief of Ordnance, who was described as being congenitally immune to new ideas.^{[says who?]}

A 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, Navy Captain 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."

World War I[link]

Tear gas casualties from the Battle of Estaires, April 10, 1918.

A Canadian soldier with mustard gas burns, ca. 1917–1918.

Soccer team of British soldiers with gas masks, Western front, 1916

The Hague Declaration of 1899 and the Hague Convention of 1907 forbade the use of "poison or poisonous weapons" in warfare, yet more than 124,000 tons of gas were produced by the end of World War I. The French were the first to use chemical weapons during the First World War, using tear gas.

The Germans' first use of chemical weapons were shells containing xylyl bromide that were fired at the Russians near the town of Bolimów, Poland in January 1915.^[20] 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 French, Canadian and Algerian troops with chlorine gas. Deaths were light, though casualties 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.^[21]

To this day unexploded World War I-era chemical ammunition is still 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 and less commonly in other countries. The French and Belgian governments have had to launch special programs for treating discovered ammunition.^{[citation needed]}

After the war, most of the unused German chemical warfare agents were dumped into the Baltic Sea, a common disposal method among all the participants in several bodies of water. 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 ambergris. Even in this solidified form, the agent is active enough to cause severe burns to anybody coming into contact with it.^{[citation needed]}

Interwar years[link]

After World War I 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. Much speculation was made about aerial bombardment of major cities with gas in Mesopotamia, with Winston Churchill, then-Secretary of State at the British War Office, arguing in favor of it.^[22]

In 1925, sixteen of the world's major nations signed the Geneva Protocol, thereby pledging never to use gas in warfare again. Notably, in the United States, the Protocol languished in the Senate until 1975, when it was finally ratified.

The Bolsheviks also employed poison gas in 1921 during the Tambov Rebellion. An order signed by military commanders Tukhachevsky and Vladimir Antonov-Ovseenko stipulated: "The forests where the bandits are hiding are to be cleared by the use of poison gas. This must be carefully calculated, so that the layer of gas penetrates the forests and kills everyone hiding there."^[23]

During the Rif War in Spanish Morocco in 1921–1927, combined Spanish and French forces dropped mustard gas bombs in an attempt to put down the Berber rebellion. (See also: Chemical weapons in the Rif War)

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. 150,000 chemical casualties were reported, mostly from mustard gas.

World War II[link]

The chemical structure of Sarin nerve gas, developed in Germany (1939)

Despite article 171 of the Versailles Peace Treaty, article V of the Treaty in Relation to the Use of Submarines and Noxious Gases in Warfare^[24] and a resolution adopted against Japan by the League of Nations on 14 May 1938, the Imperial Japanese Army frequently used chemical weapons. Because of fear of retaliation however, those weapons were never used against Westerners, but against other Asians judged "inferior" by the imperial propaganda.

According to historians Yoshiaki Yoshimi and Kentaro Awaya, gas weapons, such as tear gas, were used only sporadically in 1937 but in the spring of 1938, however the Imperial Japanese Army began full-scale use of sneeze and nausea gas (red), and from summer 1939, mustard gas (yellow) was used against both Kuomintang and Communists Chinese troops.^[25]

According to historians Yoshiaki Yoshimi and Seiya Matsuno, the chemical weapons were authorized by specific orders given by Emperor Showa himself, transmitted by the chief of staff of the army. For example, the Emperor authorized the use of toxic gas on 375 separate occasions during the Battle of Wuhan from August to October 1938.^[26]

They were also profusely used during the invasion of Changde. Those orders were transmitted either by prince Kotohito Kan'in or general Hajime Sugiyama.^[27]

Imperial Japanese soldiers wearing gas masks and rubber gloves during a chemical attack in the Battle of Shanghai.

The Imperial Japanese Army used mustard gas and the recently-developed blister agent Lewisite against Chinese troops and guerrillas. Experiments involving chemical weapons were conducted on live prisoners (Unit 731 and Unit 516). The Japanese also carried chemical weapons as they swept through Southeast Asia towards Australia.

Some of these items were captured and analyzed by the Allies. Greatly concerned, Australia covertly imported 1,000,000 chemical weapons from the United Kingdom from 1942 onwards^[28] [1]^[29] [2].^{[30][31][32][33]}

Shortly after the end of World War I, Germany's General Staff enthusiastically pursued a recapture of their preeminent position in chemical warfare. In 1923, Hans von Seeckt pointed the way, by suggesting that German poison gas research move in the direction of delivery by aircraft in support of mobile warfare. Also in 1923, at the behest of the German army, poison gas expert Dr. Hugo Stolzenberg negotiated with the USSR to build a huge chemical weapons plant at Trotsk, on the Volga river.

Collaboration between Germany and the USSR in poison gas continued on and off through the 1920s. In 1924, German officers debated the use of poison gas versus non-lethal chemical weapons against civilians. Even before World War II, chemical warfare was revolutionized by Nazi Germany's discovery of the nerve agents tabun (in 1937) and sarin (in 1939) by Gerhard Schrader, a chemist of IG Farben.

IG Farben was Germany's premier poison gas manufacturer during World War I, so the weaponization of these agents can not be considered accidental.^[34] Both were turned over to the German Army Weapons Office prior to the outbreak of the war.

The nerve agent soman was later discovered by Nobel Prize laureate Richard Kuhn and his collaborator Konrad Henkel at the Kaiser Wilhelm Institute for Medical Research in Heidelberg in spring of 1944.^[35][36] The Nazis developed and manufactured large quantities of several agents, but chemical warfare was not extensively used by either side. Chemical troops were set up (in Germany since 1934) and delivery technology was actively developed.

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. Fisk, Robert (December 30, 2000), "Poison gas from Germany", Independent, http://www.zmag.org/hussein.htm ^{[dead link]}

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.

On the night of December 2, 1943, German Ju 88 bombers attacked the port of Bari in Southern Italy, sinking several American ships– among them SS John Harvey, which was carrying mustard gas intended for use in retaliation by the Allies if German forces initiated gas warfare. The presence of the gas was highly classified, and authorities ashore had no knowledge of it– which increased the number of fatalities, since physicians, who had no idea that they were dealing with the effects of mustard gas, prescribed treatment improper for those suffering from exposure and immersion.

The whole affair was kept secret at the time and for many years after the war (in the opinion of some, there was a deliberate and systematic cover-up). According to the U.S. military account, "Sixty-nine deaths were attributed in whole or in part to the mustard gas, most of them American merchant seamen"^[37] out of 628 mustard gas military casualties.^[38] The large number of civilian casualties among the Italian population were not recorded. Part of the confusion and controversy derives from the fact that the German attack was highly destructive and lethal in itself, also apart from the accidental additional effects of the gas (it was nicknamed "The Little Pearl Harbor"), and attribution of the causes of death between the gas and other causes is far from easy.^[39][40]

Rick Atkinson, in his book The Day of Battle, describes the intelligence that prompted Allied leaders to deploy mustard gas to Italy. This included Italian intelligence that Adolf Hitler had threatened to use gas against Italy if the state changed sides, and prisoner of war interrogations suggesting that preparations were being made to use a "new, egregiously potent gas" if the war turned decisively against Germany. Atkinson concludes that "No commander in 1943 could be cavalier about a manifest threat by Germany to use gas."

North Yemen[link]

The first attack of the North Yemen Civil War took place on June 8, 1963 against Kawma, a village of about 100 inhabitants in northern Yemen, killing about seven people and damaging the eyes and lungs of twenty-five others. This incident is considered to have been experimental, and the bombs were described as "home-made, amateurish and relatively ineffective". The Egyptian authorities suggested that the reported incidents were probably caused by napalm, not gas.

There were no reports of gas during 1964, and only a few were reported in 1965. The reports grew more frequent in late 1966. On December 11, 1966, fifteen gas bombs killed two people and injured thirty-five. On January 5, 1967, the biggest gas attack came against the village of Kitaf, causing 270 casualties, including 140 fatalities. The target may have been Prince Hassan bin Yahya, who had installed his headquarters nearby. The Egyptian government denied using poison gas, and alleged that Britain and the US were using the reports as psychological warfare against Egypt. On February 12, 1967, it said it would welcome a UN investigation. On March 1, U Thant said he was "powerless" to deal with the matter.

On May 10, the twin villages of Gahar and Gadafa in Wadi Hirran, where Prince Mohamed bin Mohsin was in command, were gas bombed, killing at least seventy-five. The Red Cross was alerted and on June 2, it issued a statement in Geneva expressing concern. The Institute of Forensic Medicine at the University of Berne made a statement, based on a Red Cross report, that the gas was likely to have been halogenous derivatives - phosgene, mustard gas, lewisite, chloride or cyanogen bromide.

The gas attacks stopped for three weeks after the Six-Day War of June, but resumed on July, against all parts of royalist Yemen. Casualty estimates vary, and an assumption, considered conservative, is that the mustard and phosgene-filled aerial bombs caused approximately 1,500 fatalities and 1,500 injuries.^{[citation needed]}

Cold War[link]

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 war 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.

There is some evidence suggesting that Vietnamese troops used phosgene gas against Cambodian resistance forces in Thailand during the 1984-1985 dry-season offensive on the Thai-Cambodian border.^[41][42][43]

Developments by the Western governments[link]

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.

Also in 1952 the U.S. Army patented a process for the "Preparation of Toxic Ricin", publishing a method of producing this powerful toxin.

During the 1960s, the U.S. explored the use of anticholinergic deliriant incapacitating agents. One of these agents, assigned the weapon designation BZ, was allegedly used experimentally in the Vietnam War^{[citation needed]}. These allegations inspired the 1990 fictional film Jacob's Ladder.

Herbicidal warfare[link]

Handicapped Vietnamese children. Vietnam claims that the use of Agent Orange and other herbicides by the U.S. during the Vietnam War increased the number of birth defects.^[44]

In 1961 and 1962 the Kennedy administration authorized the use of chemicals to destroy vegetation and food crops in South Vietnam. Between 1961 and 1967 the US Air Force sprayed 12 million US gallons of concentrated herbicides, mainly Agent Orange (containing dioxin as an impurity in the manufacturing process) over 6 million acres (24,000 km²) of foliage and trees, affecting an estimated 13% of South Vietnam's land. In 1965, 42% of all herbicides were sprayed over food crops. Besides destroying vegetation used as cover by the NLF and destroying food crops the herbicide was used to drive civilians into RVN-controlled areas.^[45]

In 1997, an article published by the Wall Street Journal reported that up to half a million children were born with dioxin related deformities, and that the birth defects in North Vietnam were fourfold those in the South. The use of Agent Orange may have been contrary to international rules of war at the time. It is also of note that the most likely victims of such an assault would be small children. A 1967 study by the Agronomy Section of the Japanese Science Council concluded that 3.8 million acres (15,000 km²) of land had been destroyed, killing 1000 peasants and 13,000 livestock.

Exposure and chemical disarmament[link]

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." Several shiploads of chemical and conventional weapons were put aboard old Liberty ships and 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.

George H. W. Bush and Mikhail Gorbachev signing the bilateral treaty on 1990-06-01

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 entered into force (EIF) in 1997.

In December, 2001, the United States Department of Health and Human Services, CDC, NIOSH, National Personal Protective Technology Laboratory (NPPTL), along with the U.S. Army Research, Development Engineering Command Edgewood Chemical/Biological Center (ECBC), and the U.S. Department of Commerce National Institute for Standards and Technology (NIST) published the first of six technical performance standards and test procedures designed to evaluate and certify respirators intended for use by civilian emergency responders to a chemical, biological, radiological, or nuclear weapon release, detonation, or terrorism incident. To date NIOSH/NPPTL has published six new respirator performance standards based on a tiered approach that relies on traditional industrial respirator certification policy, next generation emergency response respirator performance requirements, and special live chemical warfare agent testing requirements of the classes of respirators identified to offer respiratory protection against chemical, biological, radiological, and nuclear (CBRN) agent inhalation hazards. These CBRN respirators are commonly known as open-circuit self-contained breathing apparatus (CBRN SCBA), air-purifying respirator (CBRN APR), air-purifying escape respirator (CBRN APER), self-contained escape respirator (CBRN SCER) and loose or tight fitting powered air-purifying respirators (CBRN PAPR). Current NIOSH-approved/certified CBRN respirator concept standards and test procedures can be found at the webpage.^[46]

United States Senate Report[link]

A 1994 United States Senate Report, entitled "Is military research hazardous to veterans health? Lessons spanning a half century,"^[47] detailed the United States Department of Defense's practice of experimenting on animal and human subjects, often without their knowledge or consent. This included:

• Approximately 60,000 [US] military personnel were used as human subjects in the 1940s to test the chemical agents mustard gas and lewisite. "Mustard" section,^[47]
• Between the 1950s through the 1970s, at least 2,200 military personnel were subjected to various biological agents, referred to as Operation Whitecoat. Unlike most of the studies discussed in this report, Operation Whitecoat was truly voluntary. "Seventh" section,^[47]
• Between 1951 and 1969, Dugway Proving Ground was the site of testing for various chemical and biological agents, including an open air aerodynamic dissemination test in 1968 that accidentally killed, on neighboring farms, approximately 6,400 sheep by an unspecified nerve agent."Dugway" section,^[47]

Project SHAD[link]

From 1962 to 1973, the Department of Defense planned 134 tests under Project 112, a chemical and biological weapons "vulnerability-testing program." In 2002, the Pentagon admitted for the first time that some of tests used real chemical and biological weapons, not just harmless stimulants.^[48]

Specifically under Project SHAD, 37 secret tests were conducted in California, Alaska, Florida, Hawaii, Maryland and Utah. Land tests in Alaska and Hawaii used artillery shells filled with sarin and VX, while Navy trials off the coasts of Florida, California and Hawaii tested the ability of ships and crew to perform under biological and chemical warfare, without the crew's knowledge. The code name for the sea tests was Project Shipboard Hazard and Defense -- "SHAD" for short.^[48]

In October 2002, the Senate Armed Forces Subcommittee on Personnel held hearings, as the controversial news broke that chemical agents had been tested on thousands of American military personnel. The hearings were chaired by Senator Max Cleland, former VA administrator and Vietnam War veteran.

Developments by the Soviet government[link]

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 1994, after a major campaign by U.S. scientists on his behalf, Mirzayanov was released.^[49]

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.^[50]

According to Mirzayanov, the Soviets also developed weapons that were safer to handle, leading to the development of the 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").^[51] Together with Lev Fedorov, he told the secret Novichok story exposed in the newspaper Moscow News.^[52]

Iran–Iraq War[link]

Iranian soldiers had to use full PPE in front line of 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.^{[citation needed]}

Chemical weapons employed by Saddam Hussein killed and injured numerous Iranians, and possibly Iraqis. According to Iraqi documents, assistance in developing chemical weapons was obtained from firms in many countries, including the United States, West Germany, the Netherlands, the United Kingdom, and France.^[53]

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.^[54][55][56]

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.^[57]

During the 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.^{[citation needed]}

Falklands War[link]

Technically, the reported employment of tear gas by Argentine forces during the 1982 invasion of the Falkland Islands constitutes chemical warfare.^[58] However, the tear gas grenades were employed as nonlethal weapons to avoid British casualties. The barrack buildings the weapons were used on proved to be deserted in any case. The British claim that more lethal, but legally-justifiable as they are not considered chemical weapons under the Chemical Weapons Convention, white phosphorus grenades were used.^[59]

Sri Lanka[link]

There have been reports of the Sri Lankan military's usage of deadly chemical weapons (in 2008 - 2009) on civilians in its fight against the Liberation Tigers of Tamil Eelam (LTTE).^[60][61][62]

Terrorism[link]

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.

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 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 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.^[63]

The first successful use of chemical agents by terrorists against a general civilian population was on June 27, 1994, when Aum Shinrikyo, an apocalyptic group based in Japan that believed it necessary to destroy the planet, released sarin gas in Matsumoto, Japan, killing eight and harming 200. The following year, Aum Shinrikyo released sarin into the Tokyo subway system killing 12 and injuring over 5,000.

On 29 December 1999, four days after Russian forces began assault of Grozny, Chechen terrorists exploded two chlorine tanks in the town. Because of the wind conditions, no Russian soldiers were injured.^[64]

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 2002 showing, among other things, the killing of three dogs by an apparent nerve agent.^[65]

On October 26, 2002, Russian special forces used a chemical agent (presumably KOLOKOL-1, an aerosolized fentanyl derivative), as a precursor to an assault on Chechen terrorists, ending the Moscow theater hostage crisis. All 42 of the terrorists and 120 of the hostages were killed during the raid; all but one hostage, who was killed, died from the effects of the agent.

In early 2007 multiple terrorist bombings have been reported in Iraq using chlorine gas. These attacks have wounded or sickened more than 350 people. Reportedly the bombers are affiliated with Al-Qaeda in Iraq^[66] and have used bombs of various sizes up to chlorine tanker trucks.^[67] United Nations Secretary-General Ban Ki-moon condemned the attacks as, "clearly intended to cause panic and instability in the country."^[68]

Demilitarisation of Chemical Weapon stocks[link]

The Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or other Gases, and the Bacteriological Methods of Warfare, or the Geneva Convention, is an International treaty which prohibits the use of chemical and biological weapons in warfare. Signed into International Law at Geneva on June 17, 1925 and entered into force on February 8, 1928, this treaty states that chemical and biological weapons are "justly condemned by the general opinion of the civilised world."^[69]

States parties to the Chemical Weapons Convention. Light colored territories are those states parties that have declared stockpiles of chemical weapons and/or have known production facilities for chemical weapons.

The most recent arms control agreement in International Law, the Convention of the Prohibition of the Development, Production, Stockpiling and Use of Chemical Weapons and on their Destruction, or the Chemical Weapons Convention, outlaws the production, stockpiling, and use of chemical weapons. It is administered by the Organisation for the Prohibition of Chemical Weapons (OPCW), an intergovernmental organisation based in The Hague.^[70]

India[link]

In June 1997, India declared that it had a stockpile of 1044 tonnes of sulphur mustard in its possession. India's declaration of its stockpile came after its entry into the Chemical Weapons Convention, that created the Organisation for the Prohibition of Chemical Weapons, and on January 14, 1993 India became one of the original signatories to the Chemical Weapons Convention. By 2005, from among six nations that had declared their possession of chemical weapons, India was the only country to meet its deadline for chemical weapons destruction and for inspection of its facilities by the Organisation for the Prohibition of Chemical Weapons.^[71][72] By 2006, India had destroyed more than 75 percent of its chemical weapons and material stockpile and was granted an extension to complete a 100 percent destruction of its stocks by April 2009. On May 14, 2009 India informed the United Nations that it has completely destroyed its stockpile of chemical weapons.^[73]

Iraq[link]

The Director-General of the Organisation for the Prohibition of Chemical Weapons, Ambassador Rogelio Pfirter, welcomed Iraq's decision to join the OPCW as a significant step to strengthening global and regional efforts to prevent the spread and use of chemical weapons. The OPCW announced "The government of Iraq has deposited its instrument of accession to the Chemical Weapons Convention with the Secretary General of the United Nations and within 30 days, on 12 February 2009, will become the 186th State Party to the Convention". Iraq has also declared stockpiles of chemical weapons, and because of their recent accession is the only State Party exempted from the destruction time-line.^[74]

Japan[link]

During the Second Sino-Japanese War (1937–1945) Japan stored chemical weapons on the territory of mainland China. The weapon stock mostly containing mustard gas-lewisite mixture.^[75] They weapons are classified as abandoned chemical weapons under the Chemical Weapons Convention and from September 2010 Japan has started their destruction in Nanjing using mobile destruction facilities in order to do so.^[76]

Russia[link]

Russia signed into the Chemical Weapons Convention on January 13, 1993 and ratified it on November 5, 1995. Declaring an arsenal of 39,967 tons of chemical weapons in 1997, by far the largest arsenal, consisting of blister agents: Lewisite, Sulfur mustard, Lewisite-mustard mix, and nerve agents: Sarin, Soman, and VX. Russia met its treaty obligations by destroying 1 percent of its chemical agents by the 2002 deadline set out by the Chemical Weapons Convention, but requested an extension on the deadlines of 2004 and 2007 due to technical, financial, and environmental challenges of chemical disposal. Since, Russia has received help from other countries such as Canada which donated C$100,000, plus a further C$100,000 already donated, to the Russian Chemical Weapons Destruction Program. This money will be used to complete work at Shchuch'ye and support the construction of a chemical weapons destruction facility at Kizner (Russia), where the destruction of nearly 5,700 tonnes of nerve agent, stored in approximately 2 million artillery shells and munitions, will be undertaken. Canadian funds are also being used for the operation of a Green Cross Public Outreach Office, to keep the civilian population informed on the progress made in chemical weapons destruction activities.^[77]

As of July 2011, Russia has destroyed 48 percent (18,241 tonnes) of its stockpile at destruction facilities located in Gorny (Saratov Oblast) and Kambarka (Udmurt Republic) - where operations have finished - and Schuch'ye (Kurgan Oblast), Maradykovsky (Kirov Oblast), Leonidovka (Penza Oblast) whilst installations are under construction in Pochep (Bryansk Oblast) and Kizner (Udmurt Republic).^[78][79]

United States[link]

On November 25, 1969, President Richard Nixon unilaterally renounced the use of chemical weapons and renounced all methods of biological warfare. He issued a decree halting the production and transport of all chemical weapons which remains in effect. From May 1964 to the early 1970s the USA participated in Operation CHASE, a United States Department of Defense program that aimed to dispose of chemical weapons by sinking ships laden with the weapons in the deep Atlantic. After the Marine Protection, Research, and Sanctuaries Act of 1972, Operation Chase was scrapped and safer disposal methods for chemical weapons was researched, with the U.S. destroying several thousand tons of mustard gas by incineration at the Rocky Mountain Arsenal, and nearly 4,200 tons of nerve agent by chemical neutralisation at Tooele Army Depot.^[80]

The U.S. ratified the Geneva Protocol which banned the use of chemical and biological weapons on January 22, 1975. In 1989 and 1990, the U.S. and the Soviet Union entered an agreement to both end their chemical weapons programs, including binary weapons. In April 1997, the United States ratified the Chemical Weapons Convention, this banned the possession of most types of chemical weapons. It also banned the development of chemical weapons, and required the destruction of existing stockpiles, precursor chemicals, production facilities, and their weapon delivery systems.

The U.S. began stockpile reductions in the 1980s with the removal of outdated munitions and destroying its entire stock of 3-Quinuclidinyl benzilate (BZ or Agent 15) at the beginning of 1988. In June 1990 the Johnston Atoll Chemical Agent Disposal System began destruction of chemical agents stored on the Johnston Atoll in the Pacific, seven years before the Chemical Weapons Treaty came into effect. In 1986 President Ronald Reagan made an agreement with the Chancellor, Helmut Kohl to remove the U.S. stockpile of chemical weapons from Germany. In 1990, as part of Operation Steel Box, two ships were loaded with over 100,000 shells containing Sarin and VX where taken from the U.S. Army weapons storage depots such as Miesau and then-classified FSTS (Forward Storage / Transportation Sites) and transported from Bremerhaven Germany to Johnston Atoll in the pacific, a 46-day nonstop journey.^[81]

In May 1991, President George H.W. Bush committed the United States to destroying all of its chemical weapons and renounced the right to chemical weapon retaliation. In 1993, the United States signed the Chemical Weapons Treaty, which required the destruction of all chemical weapon agents, dispersal systems, and production facilities by April 2012. The U.S. prohibition on the transport of chemical weapons has meant that destruction facilities had to be constructed at each of the U.S.'s nine storage facilities. The U.S. met the first three of the four deadlines set out in the treaty, destroying 45% of its stockpile of chemical weapons by 2007. Due to the destruction of chemical weapons, under the United States policy of Proportional Response, an attack upon the United States or its Allies would trigger a force-equivalent counter-attack. Since the United States only maintains nuclear Weapons of Mass Destruction, it is the stated policy that the United States will regard all WMD attacks (Biological, chemical, or nuclear) as a nuclear attack and will respond to such an attack with a nuclear strike.^[82]

As of 2011, stockpiles have been eliminated at 6 of the 9 chemical weapons depots and 89% of the 1997 stockpile has been destroyed. The U.S. anticipates closure of one more depot and a total of 90% stockpile reduction by the treaty deadline of April 2012. Destruction will not begin at the two remaining depots until after the treaty deadline and will use neutralization, instead of incineration.

See also[link]

Media related to Chemical warfare at Wikimedia Commons

• Agreement on Destruction and Non-production of Chemical Weapons and on Measures to Facilitate the Multilateral Convention on Banning Chemical Weapons
• Area denial weapons
• Biological warfare
• Chemical Ali
• Chemical Weapons Convention
• Churchill's advocacy of chemical strike against German cities
• Exotic pollution
• Lethal Unitary Chemical Agents and Munitions
• List of chemical warfare agents
• List of highly toxic gases
• Ronald Maddison
• Psychochemical weapon
• Saint Julien Memorial
• Sardasht (A town attacked with chemical weapons during the Iran–Iraq War.)
• Stink bomb
• USAMRICD
• Weapons of mass destruction
• Zyklon B

Notes[link]