On a sunny afternoon in April 1915, outside the Belgian city of Ypres, the wind began blowing in the direction the German troops wanted – toward the French lines. German soldiers set up over 5,000 barrels of chlorine gas along their position, and let loose a rolling cloud of thick, yellow death. More than 6,000 French troops died in what was the first systematic use of poison gas on the battlefield. Its effectiveness caught even the Germans off guard. Willi Siebert, a German soldier, noted in his diary, “When we got to the French lines, the trenches were empty, but in a half mile the bodies of French soldiers were everywhere. It was unbelievable.” Just over 99 years later, on June 17, 2014, the Organization for the Prohibition of Chemical Weapons (OPCW) confirmed chlorine gas was used by the Syrian government in an attack on its own people.
In 1918, a German chemist named Fritz Haber won the Nobel Prize in chemistry for a method of extracting ammonia from the nitrogen in the atmosphere. The process made ammonia abundant and easily available. Haber’s discovery revolutionized agriculture, with some calling it the most significant technological discovery of the 20th century – supporting half of the world’s food base.
Haber was also a staunch German patriot who quickly joined the war effort at the outbreak of World War I. He was insistent on using weaponized gases, despite objections from some army commanders about their brutality, and treaties prohibiting their use. He personally oversaw the first use of chlorine gas at the front lines at Ypres. The next morning, he set out for the eastern front to deploy gas against the Russian army.
Chemical weapons quickly became a mainstay of warfare, public condemnation notwithstanding. They were employed by the militaries of Italy, Russia, Spain, and Japan, among others.
1988
Iraq launches a poison-gas attack on its own city of Halabja, killing up to 5,000 Kurds, most of them civilians.
2012-18
Chemical weapons repeatedly strike rebel-held areas during Syria's civil war in attacks that Western governments blame on the Syrian government.
1935
Italy uses mustard gas during its invasion of Ethiopia.
22 April 1915
Some 168 tons of chlorine gas is released near Ypres, Belgium, by German troops against the French.
1962-71
The United States uses herbicides, including Agent Orange, and tear gas in Vietnam.
1995
The Aum Shinrikyo doomsday cult launches a sarin attack on the Tokyo subway.
1917
Mustard gas is first introduced, by German forces, prior to the Third Battle at Ypres.
1980-88
Iraq uses mustard gas and the nerve agent Tabun against Iranian forces.
1937-45
Japan uses a number of poisonous gases in China.
1950
2000
1899
The Hague Convention
Countries agree to ban the use of projectiles to diffuse "asphyxiating or deleterious gases."
2013
Russia mediates a deal to have Syria eliminate its chemical-weapons stockpiles
1992
Chemical Weapons Convention
The Chemical Weapons Convention is presented to the United Nations. It prohibits the development, production, stockpiling, transfer, or use of chemical weapons and requires signatories to destroy chemical weapon stockpiles. OPCW formed.
1925
The Geneva Protocol
The Geneva Protocol prohibits the use in war of asphyxiating, poisonous, or other gases, and of bacteriological warfare.
1899
The Hague Convention
Countries agree to ban the use of projectiles to diffuse "asphyxiating or deleterious gases."
1900
1910
22 April 1915
Some 168 tons of chlorine gas is released near Ypres, Belgium, by German troops against the French.
July 1917
Mustard gas is first introduced by the Germans, prior to the third battle at Ypres.
1920
1925
The Geneva Protocol
The Geneva Protocol prohibits the use in war of asphyxiating, poisonous, or other gases, and of bacteriological warfare.
1930
1935
Italy uses mustard gas during its invasion of Ethiopia.
1937-45
Japan uses a number of poisonous gases in China.
1950
1960
1962-71
The United States uses herbicides, including Agent Orange, and tear gas in Vietnam.
1980-88
Iraq uses mustard gas and the nerve agent Tabun against Iranian forces
1988
Iraq launches a poison-gas attack on its own city of Halabja, killing up to 5,000 Kurds, most of them civilians.
1992
Chemical Weapons Convention
The Chemical Weapons Convention is presented to the United Nations. It prohibits the development, production, stockpiling, transfer, or use of chemical weapons and requires signatories to destroy chemical weapon stockpiles. OPCW formed.
1990
2000
1995
The Aum Shinrikyo doomsday cult launches a sarin attack on the Tokyo subway.
2010
2012-18
Chemical weapons repeatedly strike rebel-held areas during Syria's civil war in attacks that Western governments blame on the Syrian government.
During the Cold War, the United States and the U.S.S.R. made major advances in chemical-weapons technology. Their breakthroughs were accompanied by innovations in nuclear-weapons technology. It was during this period that the third generation of chemical weapons was invented: nerve agents.
Within a century of their devastating debut at Ypres, chemical weapons have increased in lethality a thousandfold.
Research into chemical weapons has resulted in a thousandfold increase in lethality in less than a century. This chart compares the minimum concentrations of various chemical weapons for a lethal dose.
Phosgene
3,200
Sulfur mustard
1,000
Sarin: 35
VX: 15
Chlorine
10,000
Tabun: 70
Hydrogen cyanide
2,500
The OPCW, the United Nations, and Human Rights Watch have confirmed that chemical weapons were used at least 34 times during Syria's civil war. A UN investigation into a chemical attack on August 21, 2013, in and around the Ghouta area found that the nerve agent sarin was used on several occasions. The sarin was likely delivered via surface-to-surface rockets, like the 140mm and 330mm ones pictured below. The Syrian government has also been accused of using chlorine gas as a weapon on numerous occasions, usually released via barrel bombing.
330 mm rocket
Warhead with a capacity of 50-60 liters.
140 mm rocket
Warhead containing 2.2 kg of sarin.
Barrel bomb
Varies in size as they can be made from oil barrels, fuel tanks, or gas canisters.
Motor
Stabilizing fins
Impact fuse
Sheikh Maqsood
Aleppo
Raqqa
Saraqib
Kafr Zeita
Tamana
SYRIA
Deir-al-Zour
Khan Sheikhoun
Homs
Palmyra
Douma
Damascus
At least 1,283 people have been killed by chemical attacks in Syria, according to the Violations Documentation Center.
2018-04-07
85 dead
2013-08-21
924 dead
2017-04-15
89 dead
2016-12-12
33 dead
2013
2014
2015
2016
2018
Sarin
Chlorine
Not specified
