Chemical weapons, such as nerve gas and tear gas, have been formulated to inflict harm or death to humans. They can be widely dispersed in gas, liquid and solid forms.
First World War (1914-1918): Chemical weapons are commonly used against enemy troops. The method of delivery evolves as the war develops. The Germans initially open cans of chlorine gas when the wind is blowing towards Allied troops. The French then put phosgene into a standard shell. The Germans do most of the work on chemical weapons and in 1917 use mustard gas for the first time.
1925 – League of Nations (early UN) meets in Geneva: When details of the suffering caused by these weapons becomes known some governments begin moves to ban them and to agree what is known as the Geneva Protocol. Many countries only agree not to use the weapons first, but reserve the right to use them in retaliation. This initial protocol does not ban the manufacture of chemical weapons or the threat of their use, nor does it include details of punishment if a country is to break the protocol.
Second World War (1939-1945): No chemical weapons are used in battle but countries on both sides keep huge stockpiles of them. After the war the British, Russians and others take away stocks found in Germany and begin production plants of their own.
1950s and 1960s: Development of chemical weapons continues, including non-lethal weapons such as CS gas created by the British for riot control. Nerve gases, the most dangerous chemical weapon, are also developed out of research on insecticides. During the Vietnam war the US uses ‘Agent Orange’ to destroy the vegetation concealing the North Vietnamese. This contains the chemical dioxin, which causes deaths and deformities.
1980s: Stocks of chemical weapons are destroyed but there are continuing reports of their use. The most famous of these is the attack by Iraq on the Kurdish village of Halabja in 1988.
1992: After 12 years of negotiation the Chemical Weapons Convention (CWC) is adopted. Tougher than the 1925 treaty, the UN describes it as: “The first disarmament agreement… for the elimination of an entire category of weapons of mass destruction under universally applied international control”. It does not cover the use of CS and similar gases when used for law enforcement.
1995: Members of Aum Shinrikyo, a religious cult, attack the Tokyo subway system by releasing sarin, a deadly nerve agent. Twelve people are killed and around 6,000 injured. In 1998, the Japanese government finds and destroys the facilities used to produce the sarin.
While these countries have signed the Chemical Weapons Convention, it is likely that many have not yet destroyed all their chemical weapons. To find out more see the Organisation for the Prohibition of Chemical Weapons.
Chemical weapon treaties
Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous or other Gases, and of Bacteriological Methods of Warfare.
- Opened for signature: 1925
- Entered into force: 8 Feb 1928, and for each country as they sign it.
- As of 2010, 137 states had ratified, acceded to, or succeeded to the treaty.
Chemical Weapons Convention
- Opened for signature: 1993
- Entered into force: 1997
- Number of countries ratified: 188
Chemical weapons can be split into four main categories with different types producing different effects:
- Vesicants (e.g. sulphur mustard): causes blisters and burning of the skin, eyes, throat and lungs. Death can result from lungs filling with fluid. Can cause blindness. Sulphur mustard can cause cancers and birth defects/cancers in the children of those exposed.
- Choking agents (e.g. chlorine and phosgene): irritates the eyes, throat and lungs. Death can result from the lungs filling with fluid.
- Blood agents: stops oxygen getting to tissue and vital organs.
- Nerve agents: the most dangerous and fatal, even in very small amounts. Causes convulsions and death by respiratory paralysis. Can be absorbed through the skin and penetrates clothing.
In the First World War, when the chlorine gas cloud reached the Allied lines, a yellow fluid formed in soldiers’ lungs and there was burning of the eyes, nose and throat before they choked to death.
Mustard gas was also used and is known as a ‘blister agent’ because it attacks the skin causing burns and blisters. One of its perceived advantages is that, instead of killing, it creates many injuries that need treatment, taking up valuable time and money.
However, it can take up to 12 hours before any symptoms are evident. This was particularly noticeable during the Iran-Iraq war. The Iranians suffered terrible casualties as troops continued to wear their uniforms and breathe normally, despite the fact they were covered in mustard.
Recently some troops have worn special clothing to protect them from chemical weapons, but this can impair movement and inhibit fighting ability.
In Britain research into chemical weapons has been carried out at Porton Down, a Ministry of Defence (MoD) facility in Wiltshire since 1916. Much of this work is top secret but some aspects of it have become public in recent years.
After the First World War, volunteers for trials came from the armed forces. Early work looked at the effects of agents such as mustard gas. The MoD estimates between 6-8,000 volunteers may have been exposed to mustard.
After the Second World War nerve agents became the focus. The MoD says around 3,400 people took part in these tests from 1945-1989. In 1953 a volunteer from the RAF, 20-year-old Ronald Maddison, took part in what he thought was research into curing the common cold. About 200 milligrams of the nerve agent sarin was dripped onto his skin and he died within 45 minutes.
It took years for the truth to be uncovered. In 1999 Wiltshire police launched an investigation into 25 selected cases between 1939 and 1989. An inquest into the death of Ronald Maddison began in May 2004 and ruled he was unlawfully killed.
In February 2006 three ex-servicemen were awarded compensation in an out-of-court settlement after claims they were given LSD without their consent during the 1950s.
At least 20,000 armed service personnel took part as volunteers at Porton Down and hundreds of animals have also been used in experiments.