OPCW Confirms Banned CS Gas Found in Ukraine-Supplied Samples Amid Ongoing War

The Organisation for the Prohibition of Chemical Weapons (OPCW) has confirmed the presence of the banned riot control agent CS in multiple samples provided by Ukraine, raising fresh concerns over the use of chemical agents in the ongoing conflict with Russia. The discovery was made in nine samples collected from the frontline, including four grenade shells, three soil samples, and two vegetation samples found near a dugout.

A Growing Concern in the War Zone

CS gas, commonly known as tear gas, is not lethal but causes intense irritation to the lungs, skin, and eyes. While it is legally used for riot control by law enforcement, its use as a weapon of war is strictly prohibited under the Chemical Weapons Convention (CWC), to which both Russia and Ukraine are signatories. Despite this, accusations of chemical weapon usage have been exchanged between the two nations since the beginning of the war.

The OPCW report does not assign blame to either side but confirms that chemical agents are being used in active combat zones. This marks the second instance where riot-control agent grenades have been found in Ukraine’s Dnipropetrovsk region. The first confirmation came in November 2024, when CS was identified in three shell and soil samples from contested areas.

Alleged Chemical Attacks and International Reactions

Ukraine formally requested the OPCW’s investigation into three alleged chemical weapon incidents:

• October 2, 2024 – Near the village of Mariivka
• October 12 & 14, 2024 – Near Illinka

Following the analysis, the OPCW concluded that “all grenades collected from dugouts contained the riot control agent CS, CS-related compounds, and/or their degradation products.” The chemical was also found in soil and vegetation samples from the reported sites, reinforcing suspicions that chemical agents have been deployed in the battlefield.

OPCW Director-General Fernando Arias emphasized that the findings highlight the urgency of enforcing the Chemical Weapons Convention. “This report underscores the importance of ensuring that toxic chemical agents are not used in warfare, as outlined by international law,” he stated.

Western Allegations and Russian Denials

Ukraine’s Western allies, particularly the United States and the United Kingdom, have accused Russia of violating the CWC by using riot control agents and the highly toxic chemical chloropicrin since its invasion of Ukraine in 2022. These accusations have been strongly denied by Moscow, which insists that it no longer possesses a military chemical arsenal. However, Russia continues to face international pressure for greater transparency regarding its alleged use of toxic agents on the battlefield.

As the war drags on, the presence of chemical agents in contested areas raises troubling questions about the future of chemical warfare enforcement. The OPCW’s findings could lead to increased diplomatic scrutiny and calls for stronger international action to prevent further violations of the Chemical Weapons Convention.