#33, Second Battle of Ypres: The First Mass Poison Gas Attack in History
The Second Battle of Ypres from April 22 to May 25, 1915, killed or wounded approximately 105,000 soldiers, 59,000 Allied (35,000 British, 10,000 French, and thousands of Canadians and Belgians) and 35,000 German. It was the first battle in modern history where poison gas was used as a weapon of mass destruction, when German troops released 168 tons of chlorine gas from 5,730 cylinders along a four-mile front on April 22.
The yellow-green cloud drifted across the French 45th Algerian Division's positions, and soldiers who didn't flee suffocated where they stood. A four-mile gap opened in the Allied line. But the Germans hadn't planned for their own success, no reserves were positioned to exploit the breakthrough, and Canadian troops counterattacked with improvised gas masks (urine-soaked cloths held over their faces) to close the gap at brutal cost. The 1st Canadian Division lost 6,035 men in 48 hours at places like Kitcheners' Wood and St. Julien. Second Ypres introduced chemical warfare to the Western Front and launched an arms race in poison gas that would escalate to mustard gas, phosgene, and the development of protective equipment that soldiers would carry for the rest of the war and beyond.
