I should state that I am not a military or political historian, so I would very much appreciate your feed back on how to improve this w/u.
Chemical weapons are a kind of 'poor man's atomic bomb'.
Ali Akbar Hashemi, Iranian President, 1998

Chemical warfare is loosely defined as using lethal or incapacitating chemical agents, normally in the form of a gas, against enemy combatants. Chemical weapons are absorbed into the human body by inhalation, ingestion or absorption through the skin. They are generally classified into the following functional groups: choking gases, blister agents, blood agents (which impede the blood's ability to transport oxygen), nerve agents, incapacitants, riot-control agents, herbicides, napalm and obscuring smoke. They are normally delivered as an aerosol or a liquid, and are delivered by spraying with planes or launched with munitions.


In no future war will the military be able to ignore poison gas. It is a higher form of killing.
Fritz Haber, on receiving the Nobel Prize for chemistry, 1919.

Chemical weapons have been used against humans to a limited extent for at least 2500 years. In the 6th century BC, the Assyrians poisoned the wells of their enemies with rye ergot and Solon used hellebore during the seige of Krissa. Also, the Athenians may have used suffocating gases against the attacking Spartans in the 5th century BC. However, chemical weapons did not become used regularly in combat until the first world war.

In the late 19th and early 20th centuries, military minds in a number of European nations foresaw the coming of horrible chemical agents in the near future. In 1899, the Hague convention was signed and the participating countries agreed not to use projectiles to deliver gases. The second Hague convention clarified and reaffirmed the commitment to avoid the use of any chemical agents in future conflicts. However, while well intentioned, both agreements were in principle only; they lacked any enforcement provisions.

In 1914, as the First World War began and quickly degenerated into stagnant trench warfare, the Germans were looking to break a deadlock between them and the French. However, they did not want to be the first to break the Hague conventions. In February of 1915, they obtained documents detailing the use of turpinite by the French in 1914, and the germans felt justified in resorting to chemical weapons. They used chlorine gas (roughly one hundred and sixty tons) against Allied soldiers on April 22, 1915. This attack killed approximately 5000 troops, and another 5000 died when the attack was repeated on the 24th of April. Later in the war the British and the Germans used not only chlorine gas, but also mustard gas and phosgene regularly. In total, somewhere between 300 000 and 900 000 soldiers were killed by chemical means in WWI. The horrific nature of these weapons prompted many of the participants in WWI to sign the Geneva Protocol (see Current legality).

In World War Two, there was no use of chemcial weapons against enemy combatants, but late in the war it was discovered that the Germans had been stockpiling a new kind of chemical weapon: nerve agents. Tabun, sarin and soman, all of which were developed in the 1930s and 1940s, we found in large quantities in German weapon stockpiles.

While chemical agents may not have been used by the German military against enemy soldiers, they certainly were used in the concentration camps. Hydrogen cyanide was one of the weapons of choice used to gas Jews and other 'undesireables', as it killed quickly by causing asphyxiation. An estimated 6 million people were killed mostly by chemical means during the Holocaust.

In the 1952, scientists in the United Kingdom discovered a new and powerful chemcial weapon, codenamed VX, which was later manufactured in the United States at a plant in Utah. However, production ceased after the plant was shut down for a variety of reasons, not the least of which was the inadvertant poisoning of thousands of local sheep and cattle during an accidental emission.

During the Vietnam war, the Americans used Agents Orange, Purple, Blue and White to defoliate the tropical forests hiding the Viet Cong. While not directly targetted at humans, the impact of these chemicals on human beings has been devastating and long lasting.

Modern uses

I do not understand this squeamishness about the use of gas. I am strongly in favour of using it against uncivilised tribes.
Winston Churchill, discussing the use of chemical weapons in quelling the Iraqi rebellion, 1919.

In the 1980s and 1990s, chemical weapons have also been used by a number of regimes. The Iraqis used chemcial agents against their own Kurdish people, while the Laotians and Cambodians used chemical agents against rebellious populations. In 1988 it has been alleged that the nerve agent BZ was used against Bosnian refugees.

In these recent years, chemical weapons have also become a weapon of choice for terrorist organizations. In 1991 a neo-Nazi plot to attack a synagogue with hydrogen cyanide was thwarted in Germany. Another good example of such a useage was the attack in March of 1995 in the Tokyo subway by a fanatical cult, Aum Shinrikyo. The agent used was sarin.

There is also the question of whether American troops were attacked with chemical weapons during the Gulf War. While the Gulf War syndrome seems to have affected a large number of soldiers, no one has been able to verify whether these symptoms are indeed indicative of attacks with chemical weapons. However, it is known that the Iraqis had the capacity to produce chemical weapons, and could have deployed them during battle. They area apparently in possession of 1 to 4 thousand tons of mustard gas and the nerve agents tabun, sarin and cyclosarin.

Finally, it should be noted that both tear gas and pepper spray are technically classified, under international law, as chemical agents. While they are often used to control protestors and rioting crowds by the police and military, but may not be used in warfare. There is continuing debate as to their use in civilian settings, as some there have been some fatalities due to tear gas and pepper spray.

Current legality

Today, one of the greatest threats to American and global security is the danger that adversary nations or terrorist groups will obtain and use chemical or biological weapons.
Bill Clinton, on the 75th anniversary of the Geneva Protocol, July 17, 2000.

Geneva protocol was signed into effect in 1925, effectively banning the use of biological and chemical weapons in war. The protocol does not have any provision for enforcement, but states:

That the High Contracting Parties, so far as they are not already Parties to Treaties prohibiting such use, accept this prohibition, agree to extend this prohibition to the use of bacteriological methods of warfare and agree to be bound as between themselves according to the terms of this declaration.

The High Contracting Parties will exert every effort to induce other States to accede to the present Protocol. Such accession will be notified to the Government of the French Republic, and by the latter to all signatory and acceding Powers, and will take effect on the date of the notification by the Government of the French Republic. In 1993, the Chemical Weapons Convention was signed into force by the United Nations. It bans the use, production, development, stockpiling and transfer of all chemical weapons, and requires that existing stocks be destroyed by 2003. It further has very detailed provisions for the verification of compliance, and has its own body to execute those provisions (Organization for the Prohibitions of Chemical Weapons). This convention has been signed by 165 nations, of which 145 have or will ratify the convention. Some notable countries which have not signed the convention are Iraq, Lybia and Syria.

Common chemical agents

Some references that were used to write this document:
* http://www.nbc-med.org/SiteContent/MedRef/OnlineRef/FieldManuals/medman/History.htm
* http://www.geocities.com/CapeCanaveral/Lab/4239/chemweapons/history.html
* http://chemistry.about.com/cs/chemicalweapons/
* http://www.chem.sc.edu/faculty/morgan/cw/cw.pdf
* http://members.tripod.com/Brian_Blodgett/Chemical.htm