One of the 17 resolutions of the conference concerned the prohibition of toxic gases and read: "Contracting Powers agree to abstain from the use of projectiles whose only goal is the diffusion of asphyxiating or hazardous (toxic) gases". Only the U.S. has refused to sign the agreement and consent of the United Kingdom was caused by the general acceptance. However, this convention has been adopted and ratified by Germany, France and Austria-Hungary and ratified the ban on the use of poison gas, but all of these nations have used poison gas in the First World War. The Hague Convention of 1899, also included a prohibition on the use of poison or poisoned weapons, which embraced the USA.
Second Hague Conference – 1907
At the initiative of USA President Roosevelt held the second Peace Conference at The Hague on 15 June 18 October 1907. Restriction of the use of poison and poisoned weapons, adopted at the first conference in 1899, codified as Article 23 (a) of the conference. It was not necessary to repeat the prohibition of use of asphyxiating gases because it was completed at the previous conference, and the work of these two conferences was considered cumulative.
Versailles treaties – 1919
This agreement was signed on 28 June 1919, the representatives of the Allied forces and the German government, which included the following provisions: "Germany has banned the use of asphyxiating, poisonous gases, and all analogous liquids, materials or devices, is strictly prohibited and their production and import". This refers to the material specifically designed for the production, storage and use of these products and resources. A similar agreement was signed with Austria Alliance forces (known as Saent – Germainen Laye contract), 1920; as well as with Bulgaria 29 November 1919 (also known as the Treaty of Nenilly – sur – Seine – 1919).