One hundred years ago, in the aftermath of World War I, the international community came together to effectively ban the use of poison gas on the battlefield. The Protocol for the Prohibition of the Use of Asphyxiating, Poisonous or Other Gases, and of Bacteriological Methods of Warfare (“the Protocol”), signed on 17 June 1925, was a response to the horrors of the widespread employment of chemical weapons during the conflict.
The Protocol’s prohibitions marked a momentous leap forward in international law. Designed to prevent a repetition of the atrocities of World War I, it also laid the legal foundations for future international arms control and disarmament measures. The Chemical Weapons Convention (“the Convention”), which entered into force in 1997, built on this foundation by not only prohibiting use but also the development, production, and stockpiling of an entire category of weapons of mass destruction. Backed by a comprehensive and robust disarmament and verification regime, the implementation of the Convention is overseen by the Organisation for the Prohibition of Chemical Weapons (OPCW), which was established to ensure full compliance with a zero tolerance ban on these weapons.
Since its founding, the OPCW has achieved remarkable success in translating this legal ban into concrete action and in fulfilling the disarmament objectives entrusted to it under the Convention. In recognition of its extensive efforts to eliminate chemical weapons, the OPCW was awarded the Nobel Peace Prize in 2013. In 2023, the verified destruction of all declared chemical weapons stockpiles was completed—a historic disarmament milestone. Today, with 193 States Parties, the Convention is also nearly universal.
Yet, the threat of chemical weapons persists. In recent years, we have witnessed their use in several countries.
In Syria, the situation has been particularly serious. An important part of Syria’s chemical weapons programme has not been declared despite the efforts made by the OPCW for more than 10 years. Additionally, the OPCW has documented repeated use of chemical weapons in Syria, including by both State and non-State actors. In the war in Ukraine, the Organisation has confirmed the presence of riot control agents in samples taken from the confrontation lines—agents whose use is prohibited as a means of warfare under the Convention. At the same time, rapid advances in science and technology are raising new concerns by potentially lowering technical barriers to acquiring and deploying toxic chemicals.
The menace of chemical weapons, which the Protocol sought to end a century ago, has not subsided—it has transformed. Fortunately, the Convention’s inherent adaptability has enabled the OPCW to respond effectively to the challenges of today and remain ready for those of tomorrow. To honour the legacy of the Protocol—which rightfully affirmed that the use of chemical weapons “has been justly condemned by the general opinion of the civilized world”—the international community must remain resolute in its pursuit of a world free of chemical weapons and its long-standing zero tolerance against their use. This is an eternal debt we owe to all victims of chemical weapons.