Fritz Haber Deploys Chlorine Gas at Ypres

On April 22, 1915, German forces under Fritz Haber's direction released 168 tons of chlorine gas from nearly 6,000 cylinders along a six-kilometer front near Ypres, Belgium. The yellow-green cloud drifted into French and Algerian trenches, killing approximately 1,000 soldiers and injuring 4,000 more. Haber, already renowned for synthesizing ammonia, had personally supervised cylinder placement at the front lines. His wife Clara Immerwahr, a chemist who opposed the work, shot herself days later.