Fritz Haber Kaiser Wilhelm Institute chlorine vesicant sulfur mustard phosgene 1899 Hague Declaration Concerning Asphyxiating Gases 1907 Hague Convention on Land Warfare Russia Kaiser Russian Army German army Second Battle of Ypres Germans Hague Convention
The German army was the first to successfully deploy chemical weapons during the Second Battle of Ypres (22 April – 25 May 1915), after German scientists working under the direction of Fritz Haber at the Kaiser Wilhelm Institute developed a method to weaponize chlorine. The use of chemical weapons was sanctioned by the German High Command in an effort to force Allied soldiers out of their entrenched positions, complementing rather than supplanting more lethal conventional weapons. In time, chemical weapons were deployed by all major belligerents throughout the war, inflicting approximately 1.3 million casualties, but relatively few fatalities: About 90,000 in total. For example, there were an estimated 186,000 British chemical weapons casualties during the war (80% of which were the result of exposure to the vesicant sulfur mustard, introduced to the battlefield by the Germans in July 1917, which burns the skin at any point of contact and inflicts more severe lung damage than chlorine or phosgene), and up to one-third of American casualties were caused by them. The Russian Army reportedly suffered roughly 500,000 chemical weapon casualties in World War I. The use of chemical weapons in warfare was in direct violation of the 1899 Hague Declaration Concerning Asphyxiating Gases and the 1907 Hague Convention on Land Warfare, which prohibited their use.
