During World War I, chemical warfare agents were widely used for the first time on all major fronts with an unprecedented number of casualties, and immediately after the war attempts were made to outlaw this latest weapon. Responsibility for the drafting of specific laws fell to the League of Nations, reflecting the belief that this was a matter of concern for the whole world, not just for the victors in the war. On 17 June 1925, the Geneva Protocol for the prohibition of the use in war of asphyxiating, poisonous or other gases and of bacteriological methods of warfare was signed by 26 States.3 It contained a categorical prohibition to resort to chemical and biological warfare. The signature of the Protocol raised high hopes of an effective ban on chemical warfare, but adherence progressed slowly. A number of States, visibly not trusting the Protocol to be implemented in the forthright manner suggested by the text, made major reservations.