The 1925 Geneva Protocol banning the use of chemical and biological weapons in armed conflict turned 100 on 17 June. The 6th issue of Historical Notes traces the origins of the Protocol to the 19th century and discusses the documents that immediately preceded it, including the 1919 Versailles Treaty and the discussions on asphyxiating gases at the 1922 Washington Naval Conference. The study delves deep into how asphyxiating gases and, later, bacteriological weapons entered the deliberations in the League of Nations, and how they unexpectedly became a topic in the negotiation of an arms trade treaty. Finally, the study analyses why Poland insisted of having bacteriological weapons included in the Protocol.

On 3 October 2025, the Pugwash Chemical and Biological Weapons Working Group (CBW WG) held its first event, drawing more than 75 persons from all continents, including the Middle East and North Africa, to a virtual meeting. The primary objective was to gather feedback on potential topics for the WG’s development, thereby gaining a deeper understanding of the WG’s specific role in the current academic and civil society landscape. Registrants completed a small questionnaire covering both topics.

The control of biological weapons (BW) celebrated two major anniversaries earlier this year. On 26 March the international community lit fifty candles for the entry into force Of the Biological and Toxin Weapons Convention (BTWC). Less than three months later, on 17 June, the Geneva Protocol banning the use in armed conflict Of chemical and biological weapons (CBW) reached the venerable age of 100. Both international agreements are still in force and remain pillars supporting the international security edifice. They are also living agreements. One hundred and forty-seven States have ratified or acceded to the Geneva Protocol, Bosnia and Herzegovina having joined in 2024. The BTWC is approaching universal adherence with Kiribati becoming the 189th State party on 20 May.