On April 22, 1915, at dusk, French, Algerian, and Canadian troops were huddled in their trenches near the Belgian city of Ypres. Suddenly... they saw something strange. A cloud. Yellow-green. Creeping toward them. A meter above the ground. Covering the fields. Swallowing the trees. Like a toxic fog... It was chlorine gas. 168 tons of compressed chlorine gas released by the Germans from 5,700 cylinders. The wind carried it toward the French lines. In 10 minutes... 5,000 soldiers suffocated. Foam pouring from their mouths. Eyes burning. Lungs drowning in fluid. Panic spread. Lines collapsed. A 6-kilometer gap opened in the front. Had the Germans advanced decisively... they would have broken through the entire front. But they too were afraid of their own gas. That day was the birth of chemical warfare. The day humanity opened the gates of hell.
Summary: The Second Battle of Ypres (April-May 1915) saw the first large-scale use of poison gas in history. Germany released 168 tons of chlorine gas against French, Algerian, and Canadian troops. 5,000 killed in 10 minutes. 10,000 wounded. Panic paralyzed the front. But the Germans failed to exploit the breakthrough. The battle opened the door to the chemical arms race. By the end of the war, 90,000 had been killed and 1.2 million wounded by gas.
🧪 Science in the Service of Death
Before Ypres, the Germans had tried using tear gas on the Eastern Front (Battle of Bolimov, January 1915). But the cold froze the gas. It failed. This time, they brought something stronger. Chlorine gas. An industrial gas used in bleaching. Cheaper and easier to produce. But deadly. When it reaches the lungs, it reacts with water in the tissues and produces hydrochloric acid. The lungs fill with fluid. The victim drowns in their own body fluids. The German scientist Fritz Haber (winner of the Nobel Prize in Chemistry, 1918!) oversaw the development of the weapon. His wife, Clara Immerwahr (also a chemist), fiercely opposed him. She told him: "You are turning science into murder." On the night the Ypres attack succeeded, Haber celebrated with colleagues. He returned home... to find his wife had shot herself with his pistol. She died. Haber left for the Eastern Front the next morning. He missed her funeral. Science did not stop.
💨 April 22, 1915: The Deadly Cloud
At 5:00 PM on April 22, 1915, a moderate northern wind was blowing. The Germans had been waiting for it for weeks. 5,700 cylinders of chlorine gas (weighing 168 tons) were positioned along the front. At the signal... German soldiers opened the valves. A massive yellow-green cloud emerged. 6-9 meters high. Kilometers wide. Creeping slowly toward the French lines. Algerian guards (45th Division) and French soldiers (87th Division) saw the cloud approaching. At first, they thought it was a smoke screen to conceal a German advance. Then... it reached them. The smell of chlorine (like concentrated bleach) filled the trenches. They began to choke. Eyes burning. Yellow foam pouring from their mouths. They tried to flee. Abandoned their weapons. Ran. Many died running. In 10 minutes... 5,000 dead. 10,000 wounded. A 6-kilometer gap opened. Had the Germans advanced decisively... they would have broken through to the English Channel. But they were not ready. They were afraid of their own gas. They hesitated. The opportunity was lost.
"I saw men choking. Eyes bloodshot. Yellow foam on their lips. Some died standing up."
🇨🇦 The Canadians Fill the Gap
After the collapse of the French lines, the road to Ypres lay open. Canadian troops (1st Division) were positioned to the left of the breakthrough. They filled the gap. Launched a night counterattack (Battle of Kitcheners' Wood). Without gas masks. They wrapped urine-soaked cloths (the ammonia in urine neutralizes chlorine) around their faces. Fought all night. Recaptured some ground. Stopped the Germans. 6,000 Canadians were killed or wounded in 48 hours. One-third of the division. But they saved Ypres. Saved the front.
Gas Statistics in World War I: 90,000 killed by gas. 1.2 million wounded. 125,000 tons of gas used by both sides. Chlorine (1915), Phosgene (1915), Mustard Gas (1917).
☠️ Mustard Gas: The Worst Was Yet to Come
After chlorine, both sides raced to develop deadlier gases. Phosgene (1915): faster-acting than chlorine. Kills within hours. Mustard gas (1917): the worst. Not a true gas but an aerosolized liquid. Penetrates clothing. Burns skin. Blinds eyes. Destroys lungs. Symptoms delayed 4-6 hours. Victims suffer for days. Not as quickly lethal as chlorine. But far more terrifying. Called "the King of Gases." First used by the Germans at Ypres (July 1917). Ironically, Fritz Haber, the father of chemical warfare, was Jewish. In 1933, he fled Nazi Germany. His company developed "Zyklon B" – the gas the Nazis used in their gas chambers to exterminate 6 million Jews. Haber died in 1934. Some of his relatives died in those same chambers.
📝 The Legacy of Ypres
The Battle of Ypres changed war forever. It opened a door that has never been closed. After 1915, chemical warfare became a reality. 90,000 killed by gas in World War I. 1.2 million wounded. Many of them lived the rest of their lives disabled. In 1925, 38 nations signed the "Geneva Protocol" banning the use of poison gases. But it did not stop development. It did not stop Mussolini from using gas in Ethiopia (1935). Or Saddam Hussein from using it against Kurds and Iranians (Halabja 1988). And today... chemical weapons are still used. In Syria. In Ukraine. Ypres was the beginning. The moment humanity realized it could kill its fellow humans... simply by letting them breathe.