Declaration (IV,2) concerning Asphyxiating Gases. The Hague, 29 July 1899.
This Declaration gives expression, with regard to a particular instrument of warfare, to the customary rules prohibiting the use of poison and of material causing unnecessary suffering (cf. Oppenheim/Lauterpacht, International Law, 7th ed., Vol.2, p.342). These customary rules were formally enacted in Articles 23(a) and 23(e) of the Hague Regulations of 1899 and 1907. The prohibition of the use of poison is also mentioned in Article 70 of the Lieber Instructions, Article 13(a) of the Brussels Declaration of 1874 and Article 8(a) of the Oxford Manual adopted by the Institute of International Law in 1880. For more recent conventions concerning the use of gases, see Treaty of Washington of 1922, the Geneva Protocol of 1925 and Resolution 2603 (XXIV) of 1969 of the United Nations General Assembly.
Declaration
The undersigned, Plenipotentiaries of the Powers represented at the International Peace Conference at The Hague, duly authorized to that effect by their Governments, inspired by the sentiments which found expression in the Declaration of St. Petersburg of 29 November (11 December) 1868,
Declare as follows:
The Contracting Powers agree to abstain from the use of projectiles the sole object of which is the diffusion of asphyxiating or deleterious gases.
The present Declaration is only binding on the Contracting Powers in the case of a war between two or more of them.
It shall cease to be binding from the time when, in a war between the Contracting Powers, one of the belligerents shall be joined by a non-Contracting Power.
The present Declaration shall be ratified as soon as possible.
The ratifications shall be deposited at The Hague.
A ' procès-verbal ' shall be drawn up on the receipt of each ratification, a copy of which, duly certified, shall be sent through the diplomatic channel to all the Contracting Powers.
The non-Signatory Powers can adhere to the present Declaration. For this purpose they must make their adhesion known to the Contracting Powers by means of a written notification addressed to the Netherlands Government, and by it communicated to all the other Contracting Powers.
In the event of one of the High Contracting Parties denouncing the present Declaration, such denunciation shall not take effect until a year after the notification made in writing to the Government of the Netherlands, and forthwith communicated by it to all the other Contracting Powers.
This denunciation shall only affect the notifying Power.
In faith of which the Plenipotentiaries have signed the present Declaration, and affixed their seals thereto.
Done at The Hague, 29 July 1899, in a single copy, which shall be kept in the archives of the Netherlands Government, and copies of which, duly certified, shall be sent by the diplomatic channel to the Contracting Powers.
(Here follow signatures)