The Director-General of the Organisation for the Prohibition of Chemical Weapons (OPCW), Ambassador Fernando Arias, met with the Deputy Minister of Foreign Affairs of Ukraine, Mr Olexandr Mischenko, on the margins of the Thirtieth Session of the Conference of the States Parties (CSP-30).
The Deputy Minister and the Director-General exchanged views on the current challenges related to the implementation of the Chemical Weapons Convention (CWC) in the context of heightened geopolitical tensions. They underlined that the Convention remains a cornerstone of international peace and security and reaffirmed the need for all States Parties to uphold their obligations under the CWC.
Director-General Arias briefed Deputy Minister Mischenko on the OPCW's ongoing activities in Ukraine, including the Organisation's continued provision of technical assistance and capacity-building support under Article X of the Convention. He highlighted the findings of the three OPCW Technical Assistance Visit (TAV) reports to Ukraine-issued in November 2024 , and February and June 2025 -all of which confirmed the presence of the riot-control agent CS, related to alleged incidents that took place along confrontation lines. Director-General Arias reiterated his great concern over the findings, stressing that "the use of riot-control agent as a method of warfare is prohibited under the Convention".
Deputy Minister Mischenko expressed Ukraine's appreciation for the OPCW's work and reaffirmed the country's commitment to the Convention, stating: "A world free of chemical weapons is not a goal, it is our duty. Let us defend this Organisation, its credibility, and its mission […] Let us ensure that those who break the law of nations […] face the consequences of their actions. Let us prove that the words 'Never Again' still mean something."
Director-General Arias emphasised the collective responsibility of all States Parties to maintain and strengthen the global norm against chemical weapons: "The Chemical Weapons Convention is only as strong as the commitment of its States Parties. Upholding the norm against chemical weapons is a shared duty for all of us. On its part, the Secretariat continues to implement its mandates and support all States Parties in strengthening their capacity to address the use and the threat of use of chemical weapons."
Director-General Arias also highlighted the critical role of advancing science and technology in the implementation of the CWC. He noted that rapid scientific developments present both opportunities and risks, underscoring the need for constant adaptation to counter emerging chemical threats and prevent the re-emergence of chemical weapons.
Director-General Arias stressed the importance of the OPCW Centre for Chemistry and Technology (ChemTech Centre) in enhancing the Organisation's investigative capabilities. Director-General Arias underlined that the Centre plays an essential role in ensuring that the OPCW remains equipped to address evolving challenges and to support States Parties in strengthening preparedness and response capacities.
Background
The OPCW Technical Secretariat has been monitoring the situation on the territory of Ukraine since the start of the war in February 2022 in relation to allegations of use of toxic chemicals as weapons.
In 2024 and 2025, the Technical Secretariat conducted three Technical Assistance Visits (TAVs) to Ukraine upon Ukraine's request. The reports of all three TAVs confirmed that the samples collected by Ukraine on the battlefield contained the toxic chemical 2-Chlorobenzylidenemalononitrile, known as CS.
Both the Russian Federation and Ukraine have accused one another and reported a number of allegations of use of chemical weapons to the Organisation.
A compendium of all official correspondence by States Parties on such allegations and accusations has been made available on the OPCW public website and is regularly updated.
Under the Convention, States Parties have the obligation to declare all toxic chemical agents they hold for riot control purposes. Furthermore, the Convention explicitly prohibits the use of riot control agents as a weapon of war on the battlefield. If used as a method of warfare, these agents are considered chemical weapons and, hence, are prohibited under Article I paragraph 5 of the Convention.
Article II, paragraph 7 of the Chemical Weapons Convention, provides that a Riot Control Agent is defined as any chemical not listed in a Schedule, which can produce rapidly, in humans, sensory irritation or disabling effects which disappear within a short time following termination of exposure.
Article VIII, paragraph 38(e) of the Chemical Weapons Convention states that the Technical Secretariat shall provide technical assistance and technical evaluation to States Parties in the implementation of the provisions of the Convention, including the evaluation of scheduled and unscheduled chemicals.
As the implementing body for the Chemical Weapons Convention, the OPCW, with its 193 Member States, oversees the global endeavour to permanently eliminate chemical weapons. Since the Convention's entry into force in 1997, it is the most successful disarmament treaty eliminating an entire class of weapons of mass destruction.
In 2023, the OPCW verified that all chemical weapons stockpiles declared by the 193 States Parties to the Chemical Weapons Convention since 1997 - totalling 72,304 metric tonnes of chemical agents - have been irreversibly destroyed under the OPCW's strict verification regime.
For its extensive efforts in eliminating chemical weapons, the OPCW received the 2013 Nobel Peace Prize.
