• The history of chemical warfare (CW) traces largely back to a single man: Fritz Haber, who developed poison gases for Germany during the First World War. Haber was a world-famous chemist, who had developed a crucial process for extracting nitrates from the atmosphere. This process was used to manufacture fertilizer, and later to make explosives. Haber was a dedicated German patriot. He had a “Prussian” sense of discipline and duty, enhanced by the fact that he was of Jewish origin, though he renounced the faith in 1902. His minority background led him to want to be “more German than the Germans”.

When the war broke out in August 1914, the Germans were confident they would win, but their offensive bogged down into a bloody stalemate of trench warfare in the West. With the front deadlocked, Haber focused his mind on what he could contribute to German victory. He believed that poison gas would penetrate the strongest trenches and fortifications, allowing the German army to score critical breakthroughs through Allied defenses.
Poison gases of various sorts were already available as unwanted by-products of chemical processes. At his Berlin institute, founded by the Kaiser himself, Haber began experimenting with and refining such toxins to find those suitable for battlefield use. He initially focused on chlorine gas, the diatomic chlorine molecule, a highly reactive chemical that was used in the dye industry.
His home was on the grounds of the institute. While work and home life can clash, in the case of Haber the two quickly led to an outright war. His wife Clara was also a chemist, and was as strong-willed as he was. She believed that science should be used for constructive purposes, not to make weapons of mass destruction. Fritz Haber tried to keep Clara in the dark about his work on poison gas. In December 1914, however, there was an explosion in the lab, and one of the workers, a Professor Sachur, was hurt. Clara rushed to Sachur, who was an old friend that in fact she had introduced to her husband. The man died. Clara made her objections to her husband’s work plain, but Fritz continued his work on chemical weapons. Their marriage degenerated into warfare.
The startling thing about Haber’s work on CW is that he did it on his own initiative. In fact, he approached the German military at the end of 1914 to sell them on poison gas, but the military had no great respect for scientists, and poison gases seemed unsporting anyway. Haber still convinced them to watch a demonstration, conducted at a military testing ground outside Cologne. Clara was present, and her loathing of her husband’s activities increased.
With stalemate on the front, the German military could not be certain of victory. Defeat would be the greatest dishonor, so in early 1915 they decided to swallow their scruples and use Haber’s poison gas. They gave him officer’s rank, and he helped organize a chemical corps.

  • The Germans conducted the first chlorine gas attack on 22 April 1915, against French and Algerian troops facing them at Ypres in Belgium. The Germans set up 5,730 cylinders of chlorine gas and opened their valves. 180 tonnes (200 tons) of gas were released, forming a dense green cloud that smelled of bleach and rolled into Allied lines.

At 30 parts of chlorine to a million parts of air, chlorine gas is a nasty irritant that causes harsh coughing. At 1,000 parts per million, it is lethal, caustically stripping the lining from the lungs and causing victims to drown in their own fluids. The results of the gas attack were devastating. The French and Algerian soldiers choked, their lungs burning, and slowly died. The gas cloud tinted everything a sickly green. Those who could escape the cloud fled in panic. Before dawn on 24 April, the Germans poured gas into Canadian lines, with similar results.
Allied casualties in the two days of gas attacks were estimated at 5,000 dead, with 10,000 more disabled, half of them permanently. Despite the fact that the French had captured a German soldier who was carrying a gas mask and who provided advance details of the attack when interrogated, the report was lost in the noise and the soldiers in the trenches had no warning.
The attack was unbelievably effective. Irritant chemicals, essentially tear gases, had already been fired in artillery shells by both the French and the Germans, but they had not proven to be much more than a tactical nuisance. Even the German military was astonished by the results of Haber’s chlorine gas. To Haber’s fury, they were not prepared to exploit the breach they had made in Allied lines, and did not commit any serious force to a follow-up attack. This may have been partly because they didn’t have the protective gear for large numbers of troops at the time.
The Germans launched a number of gas attacks during May 1915, with the last taking place on 24 May. The gas attacks then ceased. The prevailing winds over the lines had changed direction, and except for two small-scale attacks in October, the Germans did not return to gas attacks in earnest on the Western Front until December. The attacks in April and May represented a squandered opportunity for the Germans. Had the gas attacks been performed on a larger scale and been followed up, they could have decisively changed the course of the war. In practice, they just made the stalemate even more miserable.

  • That was not quite realized at the time, however. German newspapers were enthusiastic over the effectiveness of poison gas, and some even claimed that gas weapons were more humane than bullets and shells. Haber was promoted to captain. He threw a dinner party to celebrate. Clara Haber was not in a congratulatory mood. They had a furious argument that evening, with Clara accusing Fritz of perverting science. He called her a traitor to Germany. Her verbal protests could not sway her husband. That night, she took his army pistol and shot herself through the heart. Fritz Haber left for the Eastern Front the next day, leaving his wife’s funeral arrangements to others.

The change in prevailing winds allowed the Germans to use their new poison gases on the Russians. On 31 May 1915, Haber supervised the first chlorine gas attack on the Eastern Front. Gas proved extremely deadly against the poorly-equipped Russians, though it was not very effective in winter cold since it tended to freeze. The Russians ended up suffering more gas casualties than all the other combatants combined, and their attempts to retaliate in kind generally proved ineffective.