International law has banned the use of chemical weapons since the Hague Convention of 1899, but that hasn’t stopped their use.
In March 2018, Sergei Skripal and his daughter were poisoned with Novichok, a fourth-generation organophosphate nerve agent developed by the Soviet Union. Skripal, a former Russian intelligence officer, had worked as a double agent for the United Kingdom. The international incident, which occurred in the UK, is being investigated as an assassination attempt by the Russian government, which it denies.
Here’s a concise history of landmark chemical weapon events, and some of the latest technologies invented to stop them, leading up to the Skripal affair:
April 22, 1915
Not long after World War I began, during the Second Battle of Ypres in Belgium, the German army, for the first time in history, directed more than 160 tons of poisonous chlorine gas (sulfur chloride) at the British, French, Canadian, and Algerian soldiers by opening approximately 600 canisters upwind of their lines.
In 1914, the French had weaponized a less than lethal tear gas made of ethyl bromoacetate. But the chlorine gas, which mixes with moisture in the lungs to create hydrochloric acid that destroys soft tissues, caused approximately 1,100 deaths and thousands of injuries at Ypres.
“I saw these Germans and I thought that they were, I wondered what they were doing, just one here and one a little further along,” said Lester Stevens from the Canadian 8th Battalion at Ypres.
“It looked like tin cans they had put over and the smoke from them boiled up and it didn’t rise, you know, the atmosphere kept it down and the wind blew it towards us, you see,” he said. “I thought it was smoke and they were going to come up behind so we started firing at them to prevent them from following up this smoke. Then when it came along towards us, it turned green, a greeny yellow color, chlorine gas, it was. It came up and went over the trenches and it stayed, not as high as a person, all the way across. Two fellows, one on my right and one on my left dropped and eventually they got them to hospital but they both died.”
The use of mustard gas became standard for both sides. A British army engineer, Captain William H. Livens, invented a special mortar for firing large canisters of gas at the German lines from 1,800 yards away. It was inaccurate but delivered several times the amount of gas that an artillery round could.
The use of chemical weapons also prompted the advent of gas masks, which are still being improved by military scientists and engineers, particularly at the U.S. Army’s Edgewood Chemical Biological Center.
After World War I, Spanish forces used air-dropped mustard gas to quell the Berber rebels in the Rif region of northern Morrocco, which was then claimed as a territory by Spain. The targets of these attacks were often civilian and carried out in revenge.
Following the Great War, the Geneva Protocol was signed, an international treaty that reaffirmed the ban on chemical and biological weapons.
As part of its imperial ambitions in Africa, the Italian army used aircraft to attack Ethiopian forces with 700 tons of sulfur mustard gas during the Second Italo-Abyssinian War. It was arguably an act of revenge.
“The object was to scatter fear and death over a great part of the Ethiopian territory. These fearful tactics succeeded. Men and animals succumbed. The deadly rain that fell from the aircraft made all those whom it touched fly shrieking with pain. All those who drank the poisoned water or ate the infected food also succumbed in dreadful suffering. In tens of thousands, the victims of the Italian mustard gas fell,” Ethiopian Emperor Haile Selassie said in a 1936 appeal to the League of Nations.
Dr. Gerhard Schrader, a German chemist, began testing organophosphate molecules for potential as insecticides. His work produced tabun and sarin, deadly nerve agents that were mass produced during World War II but not used.
Sarin is a transparent, colorless, and tasteless fluid that has no odor and can evaporate into a vapor and easily spread. It strikes the nervous system by impeding the degradation of the neurotransmitter acetylcholine at neuromuscular junctions. Convulsions prelude a comatose death by asphyxia.
1937 – 45
During the Second Sino-Japanese War that began in 1937, the Empire of Japan frequently used cyanide and mustard gas when conventional attacks failed to reduce Chinese defenses. After the war, China estimates that Japanese soldiers buried or abandoned more than 2 million chemical weapons in China, presenting an on-going environmental hazard.
Otherwise, during World War II, no chemical weapons were used in combat. However, Nazi Germany used Zyklon B, a cyanide-based pesticide, to kill more than one million people, mostly Jews, in gas chambers operated as part of concentration camps like Auschwitz.
1947 – 91
Following World War II, both the United States and the Soviet Union manufactured massive stockpiles of chemical weapons as part of the Cold War. Fortunately, none were used in combat.
1963 – 67
Intervening in the Yemeni Civil War, Egyptian forces used mustard and phosgene gas against royalist forces. The total number of deaths attributed to the use of gas number 1,400.
1980 – 88
During the Iran-Iraq War, Iraqi forces used the deadly nerve agents sarin and tabun against Iran. Saddam Hussein’s regime also used chemical weapons (mustard gas, and nerve agents Sarin, Tabun, and VX) against Kurdish towns in Iraq, including the 1988 attack on Halabja, which killed more than 3,000 people.
Aum Shinrikyo, a doomsday cult in Japan, unleashes a homemade alternative of Sarin on a Tokyo subway. The attack killed 12 people and wounded another 1,000. The same group had nine months earlier used sarin to attack an apartment building in Matsumoto where three judges lived. The judges were overseeing a real-estate lawsuit against the cult. Five people were found dead in their apartments, two died in the hospital, and nearly 300 were treated for exposure.
The U.S. Naval Surface Warfare Center, Dahlgren Division, invented a novel chemical and biological warfare decontamination solution using peracids and germinants. Learn more.
The Edgewood Chemical Biological Center invents a new chemical and biological weapon air filter that can be molded into various shapes that would prevent the user from becoming fatigued by heavy breathing. The filter is patented, but the design is available via license to businesses that would manufacture it. Learn more.
U.N. investigators have confirmed that chemical weapons have been used numerous times in Syria’s 7-year-old civil war. In one attack on the rebel-held Ghoutta area near the capital Damascus, the Assad regime killed between 200 and 1,800 people with sarin gas delivered by rockets. In another attack, on the village Kfar Zeita, the Syrian government dropped a chlorine gas bomb from a helicopter.
In 2014, the U.S. Army invented a field-deployable hydrolysis system that can be taken to foreign countries like Syria and used to destroy chemical weapons.
The U.S. Naval Research Laboratory filed for a patent on a broad-spectrum, toxic gas filter using a manganese oxide nanoarchitecture. The technology is available to businesses for productization.
Kim Jong-nam, the older half-brother of North Korean dictator Kim Jong-un, is assassinated with VX nerve agent at the Kuala Lumpur International Airport in Malaysia. While in the airport, two women splashed the poison into Jong-nam’s face and then covered it with a cloth. It’s widely believed the assassination was ordered by the North Korean government.
Researchers at the U.S. Army’s Edgewood Chemical and Biological Center have invented a novel enzyme that can quickly arrest VX. The compound is patented, and available to companies that would develop it into a market-ready product. Learn more about the VX decontamination technology.
The Assad regime in Syria drops sarin on rebels in Khan Shaykhun, a town in the Idlib province. Seventy-four people, including children, are killed or wounded by the gas attack. The bombing prompts retaliatory missile strikes from a U.S. warship against the Syrian air force unit believed responsible.
Naval ships prepare for chemical and biological threats through constant air cleaning. There are over 100 M98 collective protection air filters in use on a U.S. Navy destroyer. The same filter is used on thousands of the Army’s ground vehicles. While effective at removing toxins, collective protection air filters are degraded by common ambient air contaminants including sulfur dioxide, nitrogen dioxide and vapors from diesel, jet, and auto fuel. The annual cost of replacing these filters is several million dollars. To address this cost, A team of Army and Navy researchers developed an initial filter, called a guard bed, situated upstream of the collective protection filter that can remove filter degrading compounds.
Shortly after the Novichok attack against Sergei Skripal in the UK, the Syrian government again uses chlorine gas to attack the rebel-held city of Douma. A Syrian helicopter is reported to have dropped the chemical bomb on an apartment building. More than 40 people were found dead, and scores more wounded.