Russian Military Uses Chemical Agents as a Standard Battlefield Tactic

Russian Military Uses Chemical Agents as a Standard Battlefield Tactic

Executive Summary:

• Igor Kirillov, head of Russia’s Nuclear, Biological, and Chemical Protection Troops, was killed in Moscow in December 2024, shortly after Ukraine’s Security Service accused him of responsibility for the systematic use of prohibited chemical agents against Ukrainian forces. 
• The continuation of chemical attacks after his death suggests that the practice was not dependent on a single commander, but is part of a broader military, production, and logistics system. 
• Russian forces use gas grenades and improvised devices containing irritant agents to drive Ukrainian troops from shelters and expose them to conventional fire. The Organization for the Prohibition of Chemical Weapons has confirmed the presence of 2-chlorobenzalmalononitrile (CS), commonly called tear gas, in samples from the front lines. 
• Ukraine is building an evidentiary foundation for identifying those responsible, from battlefield operators and commanders to manufacturers and munitions suppliers. The gap between international law and the evidentiary requirements of criminal prosecution complicates accountability for the use of CS, chloroacetophenone (CN), and chloropicrin.

As of September, Ukraine reported nearly 14,000 cases of Russia using hazardous chemical substances on the front lines (Telegram/@GeneralStaffZSU, July 2; Armiia Inform, September 15). The main means of delivery were hand-thrown gas grenades and improvised devices containing 2-chlorobenzalmalononitrile (CS)—commonly called tear gas—and chloroacetophenone (CN)—the active ingredient in mace—dropped from drones onto Ukrainian positions. In July, at the 112th Session of the Organization for the Prohibition of Chemical Weapons Executive Council, the European Union and 12 more states condemned Russia’s use of riot-control agents and other toxic chemicals against Ukraine and called for those responsible to be identified (OPCW, accessed September 30). This indicates that the issue is gradually moving from the documentation of individual attacks toward international recognition of their systemic character and the search for mechanisms of accountability.

The Chemical Weapons Convention, which Russia is a party to, expressly prohibits the use of riot-control agents as a method of warfare (Chemical Weapons Convention, accessed September 30). On the battlefield, Russian forces use these substances to force Ukrainian service members out of shelters, temporarily incapacitate them, and make them vulnerable to strikes with conventional weapons (Armed Forces of Ukraine, June 3).

On December 17, 2024, an explosion outside a residential building in Moscow killed Lieutenant General Igor Kirillov, head of Russia’s Nuclear, Biological, and Chemical Protection Troops. One day earlier, the Security Service of Ukraine (SBU) announced charges against him in absentia, accusing him of organizing the mass use of prohibited chemical agents against Ukrainian forces. An SBU source told Reuters that the explosion was a Ukrainian operation, but Ukraine has not officially taken responsibility for Kirillov’s death (Reuters, December 17, 2024).

Kirillov’s death did not halt the use of chemical agents against Ukrainian troops. Incidents after his death indicate that the practice was not tied to a single commander, but is an institutionalized element of Russian battlefield tactics. Russian forces continue to drop gas grenades and improvised devices containing irritant agents onto Ukrainian positions, significantly increasing personnel losses. Ukraine recorded the highest intensity of chemical weapon use in 2025, when nearly 900 incidents occurred in a single month (Facebook/Support Forces Command of the Armed Forces of Ukraine, December 19, 2025).

Ukrainian military authorities repeatedly identify the same types of munitions, delivery methods, and tactical purpose for Russian use of chemical agents. Russian forces use K-51 and RG-Vo grenades, as well as improvised devices, dropping them from drones into trenches, dugouts, and other enclosed defensive positions. The irritant causes coughing, tearing, breathing difficulties, disorientation, nausea, and temporary incapacitation. Service members are forced to leave protected positions, after which they come under fire (Armed Forces of Ukraine, June 3).

Radio intercepts released by Ukraine’s Main Directorate of Intelligence of the Ministry of Defense of Ukraine (HUR/GUR or DIU) illustrate this operational pattern. In May 2025, a Russian commander suggested “trying chemicals” against a Ukrainian position (HUR, May 20, 2025). In July 2025, Russian service members discussed plans to “blow” a toxic substance into a Ukrainian defensive structure (HUR, July 8, 2025). In another intercept, a commander said he intended to “gas” Ukrainian troops sheltering in a basement and then ordered that they be finished off quickly while they were coughing and disoriented (Telegram/@DIUkraine, July 24, 2025). Dozens of such recordings released by Ukrainian intelligence do not, on their own, constitute independent international verification of each incident, but they are consistent with Russian tactics described by Ukrainian service members.

Individual combat episodes show how chemical agents are integrated into conventional assault operations. In May 2025, three Ukrainian special operations troops from the Artan X unit were incapacitated by gas and captured. After their release, they underwent hospital treatment that Defense Intelligence linked to exposure to Russian chemical agents (HUR, May 8, 2025). On the Kupiansk axis, Russian forces used a toxic gas against a servicemember from the Bratstvo unit and then subjected his position to heavy mortar fire and first-person view drone attacks. The servicemember sustained multiple shrapnel wounds and chemical poisoning (HUR, July 17, 2025).

In an anonymous interview with this author, a representative of the command of Ukraine’s Assault Forces said he had repeatedly been exposed to unidentified chemical substances on the Dnipropetrovsk axis. During the most recent incident, in 2025, he had just stepped out of a vehicle when a munition dropped from a drone exploded nearby. The servicemember saw a small cloud of smoke with no distinct odor, after which he began coughing and experienced a sweet taste, intense burning in his respiratory tract, and tearing. His medical records documented poisoning by an unidentified substance, chemical burns to the lungs, and emphysema. He underwent two separate two-month courses of hospital treatment. The servicemember believes he may have been exposed to chlorine, although the substance was not confirmed through laboratory analysis. According to him, his unit was operating against the Russian Rubikon formation at the time, which regularly employed chemical agents. “After two courses of treatment, my respiratory function was partially restored—from about 40 to 80 percent. Some of my subordinates suffered even more severe consequences, including burns to the trachea and respiratory tract,” the soldier said (Author’s Interview via The Reckoning Project, August 6).

Victim testimony is crucial because the term “tear gas” can create the misleading impression of a relatively safe policing tool used in peacetime. On the battlefield, the same agents are employed in a different environment and for a different purpose. They are dropped into enclosed spaces from which troops may be unable to escape quickly, often while under fire and without access to immediate medical assistance. Even when the chemical agent itself is not lethal, it ultimately exposes service members to conventional fire. In this sense, an irritant agent becomes part of a lethal battlefield sequence.

In February and June 2025, the Organization for the Prohibition of Chemical Weapons (OPCW) published reports following technical assistance visits to Ukraine. The experts reviewed documentation and digital materials, conducted first-hand witness interviews, assessed sample-collection procedures and compliance with chain-of-custody requirements, and submitted samples for analysis by two independent OPCW-approved laboratories. In both cases, the analysis confirmed the presence of the CS, a riot control agent, and/or CS-related compounds or degradation products in samples collected from specific alleged incidents along the frontline (OPCW, February 14, 2025; OPCW, June 20, 2025).

The legal assessment of such attacks depends on the specific substance used. CS, CN, and chloropicrin differ in toxicity and therefore cannot automatically be subject to the same legal classification. The use of the tear-gas agent CS as a method of warfare is expressly prohibited by the Convention. At present, the use of CS on the Ukrainian frontline has the strongest independent corroboration.

CN is also classified as a riot-control agent and is more toxic than CS. In January 2024, Ukrainian military experts reported that an examination of a Russian RG-Vo gas grenade had identified CN among its contents (Armed Forces of Ukraine, January 25, 2024). The General Staff separately emphasized that K-51 and RG-Vo grenades should not be described as conventional lethal chemical-warfare agents (Armiia Inform, November 11, 2024).

Chloropicrin falls into a separate category. It is a significantly more toxic substance capable of causing death or severe damage to the respiratory system. In 2024, the United States formally determined that Russia had used chloropicrin against Ukrainian troops during combat operations and imposed related sanctions (U.S. Department of State, May 1, 2024). Ukrainian investigators have also reported repeated use of ampoules containing the substance, while Dutch and German intelligence services wrote in 2025 that Russia was using it with increasing frequency (Netherlands Ministry of Defense, July 4, 2025). At the same time, no separate public statistics exist on the number of confirmed chloropicrin incidents, and the evidentiary record for specific cases remains less systematic than the laboratory confirmation available for Russia’s CS use.

This distinction matters both for chemical identification and for the criminal prosecution of those responsible. Despite the prohibitions contained in the Chemical Weapons Convention, not every violation of international humanitarian law automatically falls within a specific war-crime provision of the Rome Statute, the international treaty that established and governs the International Criminal Court (Journal of International Criminal Justice, October 22, 2025). Article 8(2)(b)(xviii) of the Rome Statute criminalizes the use of asphyxiating, poisonous, or other gases and analogous liquids, materials, or devices. The “Elements of Crimes,” which provide details on what prosecutors must prove to establish an offense, however, require that the substance cause death or serious damage to health through its asphyxiating or toxic properties. For CS and CN, the principal typical effect is temporary incapacitation, but the legal argument may be stronger in the case of chloropicrin because of its substantially greater toxicity.

There is a legal gap between the broad prohibition of chemical weapons under international law and the ability to hold a specific individual criminally responsible under war-crime provisions. It is difficult to move from documentation of an incident to chemical identification, attribution to a specific unit, establishment of an order, and proof of a commander’s individual intent.

Ukraine is responding to Russia’s use of chemical agents on several levels. The first is the direct protection of its troops. In recent years, chemical, biological, radiological, and nuclear reconnaissance units have received sustained assistance from Western partners in the form of personal protective equipment, training for chemical attacks, and evacuation procedures for contaminated positions.

Documentation is an equally important part of Ukraine’s response. Specialized units, working with law-enforcement investigative teams, collect used grenades and other weapons, munition fragments, soil and vegetation samples, medical records, and service members’ testimony. This system has produced statistics covering thousands of incidents and provided material for national forensic examinations and international technical missions.

Representatives of the Office of the Prosecutor General have emphasized that Ukraine is systematically documenting such incidents, conducting criminal investigations, and cooperating with the OPCW to preserve evidence and secure its international verification. According to prosecutor Taras Semkiv, their office seeks to confirm the use of prohibited substances and identify specific individuals involved in ordering and carrying out the attacks (Office of the Prosecutor General of Ukraine, February 28, 2025).

The charges brought against Kirillov in absentia are the most prominent example of efforts to individualize responsibility for Russia’s systematic use of prohibited chemical agents in Ukraine. Dismantling the broader structure, however, requires investigators to also identify the individuals who transmitted orders, drone operators, personnel responsible for the storage and supply of munitions, and actors throughout the chain of chemical-agent production and logistics.

The HUR identified the Russian Federal Research and Production Center “Research Institute of Applied Chemistry” in Sergiev Posad as the enterprise that supplied the Russian military with RG-Vo grenades containing a toxic substance. The enterprise is subordinate to the state corporation Rostec. This connection extends responsibility beyond a single general or military unit and points to a broader state-controlled production system (HUR War and Sanctions, accessed September 30).

The killing of Igor Kirillov was a symbolic blow to Russia’s command hierarchy, but it did not alter the practice of using chemical agents. Ukraine is gradually building the evidentiary architecture that had previously been lacking. It is systematically documenting incidents, preserving samples through a proper chain of custody, securing independent laboratory verification, and identifying commanders and institutional links.