The Organisation for the Prohibition of Chemical Weapons (OPCW), an international watchdog, announced on Thursday that it has detected the presence of a banned tear gas, CS gas, in various samples submitted by Ukraine. This finding comes amid ongoing accusations by Ukraine that Russia has employed riot control agents on the front lines of the conflict.
This marks the third instance the OPCW has confirmed the use of CS gas in active combat zones in Ukraine. The samples in question encompassed two grenade shells, two soil samples, two samples of vegetation, and remnants of a drone—all collected from areas experiencing significant military engagement.
In addition to analyzing these samples, the OPCW gathered supporting materials including documents, digital files, and eyewitness testimonies. Importantly, the report refrained from attributing blame to either Ukraine or Russia for the use of this banned substance, which is prohibited in conflict situations under the Chemical Weapons Convention. The convention explicitly bans the use of riot control agents, such as CS gas, as a method of warfare.
Both Russia and Ukraine have leveled accusations at one another regarding the deployment of chemical weapons throughout the nearly three-year-long conflict. Kyiv’s Western allies have also voiced concerns that Moscow has resorted to utilizing prohibited weaponry.
The OPCW’s previous reports indicated the presence of CS gas in Ukrainian samples collected in November 2024 and again in February of the current year. OPCW director general Fernando Arias expressed deep concern over the repeated instances of riot-control agent grenade discoveries near active conflict zones, particularly in the Dnipropetrovsk region. He emphasized the urgent need for enhanced compliance with the Chemical Weapons Convention to prevent further escalations in prohibited warfare.
