Chemical weapons: A history from Passchendaele to Syria
Mustard gas horrified the world in 1917 - and its deadly legacy continues today
Europe fell silent today to honour the centenary of the Battle of Passchendaele, one of the bloodiest battles of World War One and the first in which mustard gas was used effectively as a weapon.
Chemical weapons gained notoriety during the conflict, not only for their lethality but for the manner in which the victims suffered before death.
The 1925 Geneva Protocol banned the use of all chemical weapons, but has not prevented their subsequent use.
The first gas attacks
By the end of World War I, 91,000 soldiers on all sides had been killed in gas attacks - less than ten per cent of deaths during the entire conflict.
"Machine guns and artillery shells, it turns out, were far more effective systems for delivering death," Politico says.
Conventional weapons may have killed many more soldiers, yet chemical weapons were intensely scrutinised by world leaders because of their psychological consequences, leading to the 1925 Geneva Protocol prohibiting the "Use in War of Asphyxiating, Poisonous or other Gases, and of Bacteriological Methods of Warfare".
The agreement, adds Politico, was signed " most prominently by those who had used gas in the Great War - Austria, Britain, France, Germany and Russia, (the US signed the protocol, but the Senate did not ratify it until 1975".
The protocol stated that use of such weapons had been "justly condemned by the general opinion of the civilised world", despite having been used by both sides.
The reasons for the condemnation are contentious, however.
Why ban chemical weapons?
Many felt the suffering of the victims in World War I was too barbaric to ignore. Mustard gas causes the skin to blister, induces vomiting and causes internal and external bleeding. Soldiers who had been attacked had to be strapped to their beds.
In her autobiography Testament of Youth (1933), nurse Vera Brittain: "I wish those people who talk about going on with this war whatever it costs could see the soldiers suffering from mustard gas poisoning. Great mustard-coloured blisters, blind eyes, all sticky and stuck together, always fighting for breath, with voices a mere whisper, saying that their throats are closing and they know they will choke."
Survivors were often left scarred and blinded and their suffering continued long after the war had finished.
The Geneva Protocol may have been signed for somewhat more practical reasons, however, as weapons "proved difficult to control", says Politico.
"In several well-documented instances, gases deployed by front-line troops blew back onto their own trenches," it continues. Civilian populations were also often affected by wind-blown gas attacks, leading to their ban.
In addition, it was feared that technological advancements would inevitably make chemical weapons deadlier and more difficult to combat, The Atlantic reports.
Who has broken the rules?
While the Geneva Protocol banned the use of chemical weapons in warfare, it did not prohibit their production. Stockpiling continued throughout the 20th century, particularly by the US and USSR during the Cold War.
Even after the 1993 Chemical Weapons Convention, which saw a blanket ban on production and stockpiling, storage and attacks continued, reports National Public Radio (NPR).
Chemical weapons were used in the 1980s during the Chadian–Libyan conflict and the Iran-Iraq war, as well as the first Gulf war in 1990.
By 2013, however, it appeared substantial progress had been made to destroy and contain their use.
"We have now verified the destruction of about 80 per cent of all the chemical weapons stockpiles that have been declared to us," Michael Luhan, spokesman for the Organisation for the Prohibition of Chemical Weapons, said NPR.
But it was the other 20 per cent of weapons that continued to cause distress and death.
Syria has never signed the convention and is "widely believed to possess sizeable stocks of different kinds of chemical weapons", writes the Council on Foreign Relations.
In 2013, the UN accused Syria of using a sarin nerve agent against civilians during the civil war. Although those responsible were not identified, the UN said they "likely had access to the chemical weapons stockpile of the Syrian military", Reuters reported.
It added: "The team of independent experts, led by Brazilian Paulo Pinheiro, said that so far they had confirmed the deadly nerve agent sarin was used in three incidents: the Damascus suburb of al-Ghouta on August 21, in Khan al-Assal near Aleppo in March 2013 and in Saraqeb near the northern town of Idlib last April".
US president Barack Obama issued a warning to Syria, saying chemical attacks were a "red line". However, he did not specify what action the US was prepared to take, The Independent said.
When the regime later crossed the "red line", Obama was unable to do anything because he did not receive approval from Congress.
"The chemical weapons conventions are being disregarded with impunity" and in the face of claims and counterclaims, it looks as though the Geneva Protocol may have failed, says EuroNews.
And as with many lessons in life - from Passchendaele to Syria - those who do not learn history are doomed to repeat it.