At the dawn of the 20th century, world military powers feared that future wars would be decided by chemistry as much as artillery, so they signed a pact at the Hague Convention of 1899 to ban the use of projectiles. loaded with poison “the only object of which the diffusion of asphyxiating or deleterious gases.”
Yet from the start of World War I, the Allies and Central Powers deployed noxious gases to neutralize the enemy or at least sow fear in their hearts. After the first efforts of the French and German armies to use tear gas and other combat irritants failed, the first successful gas attack was launched by the Germans against the British in the Second Battle of Ypres on April 22 1915.
At the start of the battle, the Germans released 170 tons of chlorine gas from more than 5,700 bottles buried in a four mile line across the front. British officer Martin Greener described the horror of this first large-scale gas attack at the Imperial War Museum.
“[T]The next thing we heard was that sizzle – you know, I mean you could hear that damn thing happening – and then I saw that awful cloud coming. A large yellow cloud, greenish yellow. It was not very high; about i would say it was no more than 20ft tall. No one knew what to think. But immediately we knew what to think, I mean we knew what it was. Well, sure, you immediately started choking, and then the word came: whatever you do, don’t fall. See, if you got to the bottom of the trench, you took full advantage of it because it was a heavy thing, it fell.
None of the British soldiers in Ypres wore gas masks, leaving 7,000 wounded and over 1,100 dead from asphyxiation with chlorine gas. Many deaths occurred when panicked victims rushed to drink water to relieve themselves of the burning gas, which only worsened the chemical reaction, flooding their throats and lungs with hydrochloric acid.
WATCH: World War I: The First Modern War in HISTORY Vault
British outrage turns into retaliation
Britain’s reaction to the German gas attack has been “scandalous,” says Marion Dorsey, professor of history at the University of New Hampshire and author of A strange and formidable weapon: British responses to the poisonous gases of World War I. “Did [the Germans] technically violate the Hague Convention ”, which specifically prohibits projectiles filled with toxic gases? “No. But did they violate the spirit of the ban? Absolutely.”
Sir John French, Commander-in-Chief of the British Expeditionary Force, denounced the attack as proof of German barbarism: “All of Germany’s scientific resources have apparently been put into play to produce a gas of such a virulent nature and toxic that any human being in contact with it is first paralyzed, then meets a persistent and agonizing death.
Before British troops were given proper gas masks with rubber gaskets called respiratory protective masks, they were fitted with temporary solutions, like thick gauze pads that were firmly attached to the mouth. A stretcher bearer in Ypres named William Collins described the pads as more stuffy than gas:
“I found out that by using it in the gas cloud, after a few minutes you couldn’t breathe and so it was pushed over the forehead and we swallowed the gas. And could only put it off for very short periods of time. It was not at all a practical proposition.
It didn’t take long for British officers like the French to change their stance on chemical warfare. If the Germans were to sink as low as to use gas, then why should the Allies take to the heights? Shortly after French made his public statement on the barbarism of the German gas attacks, he wrote a private cable to Lord Kitchener, the British Secretary of State for War: “We are taking every precaution we can think of. , but the most effective would be to turn their own weapon against them and stick to nothing.
Kitchener was quick to develop its own British chemical arsenal. He founded Porton Down, a research center in the English countryside dedicated to the defense of Allied troops against gas attacks and the storage of their own gas weapons for use against the Germans.
“British policy was to respond in kind to German gas attacks, but never to escalate the war,” says Dorsey.
At the end of September 1915, the British attempted to give the Germans a dose of their own medicine at the Battle of Loos, with little success. The Royal Engineers released gaseous chlorine an hour before the infantry was scheduled to attack, but the winds shifted, sending clouds of chlorine back towards the British line and forming a poisonous fog in no man’s land.
“The gas hung in a thick veil over everything, and it was impossible to see more than ten meters,” a British officer wrote to Loos. “In vain, I looked for my landmarks in the German line, to guide me to the right place, but I could not see through the gas.”
READ MORE: Life in the trenches of WWI
The death toll of phosgene and mustard gas
While chlorine gas could kill in concentrated amounts, it was more or less neutralized with the widespread deployment of gas masks in 1917. By this point, however, both sides had discovered much deadlier and more cruel chemicals: phosgene and mustard gas.
Phosgene is an irritant six times more deadly than chlorine. Instead of announcing its presence in a yellow-green cloud, phosgene is colorless and takes its time to kill. Victims do not know they were exposed until a few days after inhalation, when their lungs fill with fluid and they suffocate. The Germans were the first to use phosgene in combat, but the Allies made it their main chemical weapon later in the war.
Mustard gas was a whole new kind of killer chemical. It is not an irritant, but a “vesicant,” a chemical that blisters and burns the skin on contact. Even though soldiers wore gas masks to protect their lungs, mustard gas would seep into their woolen uniforms and even burn through the soles of their boots, Dorsey says.
In June 1918, the Allies were using mustard gas as a last ditch effort to break the deadlock at Ypres. A young Adolf Hitler was among the German troops injured and temporarily blinded by these attacks.
By the end of the war, around 6,000 British soldiers had been killed by the gas, a fraction of the 90,000 total deaths in WWI by chemical weapons, more than half of which were caused by the Russians, who had access limited to gas masks.
Anti-war movement calls for arms control treaties
In the aftermath of World War I, as nations mourned the deaths of tens of millions of soldiers and civilians, most military leaders admitted that chemical weapons would continue to be part of the new barbarity of war. But that sentiment was countered by a growing anti-war movement that pushed for arms control treaties and greater diplomacy.
In 1925, the League of Nations adopted the Geneva Protocol, which prohibits the use of chemical and biological agents in time of war, but does not prevent nations from continuing to develop and stockpile such weapons.
During World War II, Nazi Germany killed millions of concentration camp victims in gas chambers filled with carbon monoxide or the pesticide Zyklon B, but decided not to deploy a new class of nerve gases in the battle for fear of Allied retaliation. China has also accused Imperial Japan of firing mustard-gas-filled artillery and other blistering agents during World War II. During the Vietnam War, the United States used chemical weapons napalm and Agent Orange with terrible effect.
The current ban on chemical weapons was enshrined in international law by two conventions in 1972 and 1993.