The international community should immediately investigate accusations that the Islamic Republic attacked demonstrators with weapons of mass destruction.

More than 30 human rights and civil society groups are urging the United Nations to investigate allegations that Iran’s regime deployed chemical weapons against protesters in January 2026. This call echoes concerns raised in a January 22, 2026, European Parliament resolution condemning the regime’s brutal suppression of nationwide protests.  

Eyewitnesses and victims from the violent crackdowns have reported that security forces used agents far more lethal than standard tear gas. “‘What was fired was not tear gas,’ one protester recounted. ‘People collapsed,’ another eyewitness said.” Iran, as a party to the 1997 Chemical Weapons Convention (CWC), has faced repeated US citations for non-compliance.

Given these serious allegations, Iran’s history of treaty violations, and the scale of the repression—which resulted in thousands killed—the claims demand thorough, independent scrutiny and sustained attention from the United States and its allies, as well as the CWC’s implementing multilateral body, the Organization for the Prohibition of Chemical Weapons (OPCW).

Testimonies and information gathered by Iran International and other sources raise serious concerns about the possible use of chemical weapons by security forces.

Victims described exposure to gases that “caused intense burning of the eyes, skin and lungs, along with acute respiratory distress, repeated coughing, dizziness, loss of balance and, in some cases, vomiting or coughing up blood. Witnesses said the severity and persistence of the symptoms differed from their past experiences with tear gas, although they said they could not identify the substances used.”

According to Iran International, other witnesses described a “smell [that] resembled ammonia, drain cleaner and, in some areas, mustard.” The outlet reported that, “In addition to tear gas, witnesses spoke of ‘unknown gases with more severe effects,’ saying those exposed experienced sudden weakness, inability to walk, and loss of breath.”

As a state party to the CWC, Iran is prohibited from developing, stockpiling, or using chemical weapons. The treaty defines chemical weapons as those that “cause death, temporary incapacitation or permanent harm.” It permits the use of riot-control agents (RCAs), such as tear gas, for domestic law enforcement, defining RCAs as chemicals that “produce rapidly in humans sensory irritation or disabling physical effects [but] disappear within a short period of time following termination of exposure.”

This law-enforcement exception does not apply to chemicals that target the central nervous system (CNS) or cause lasting harm, even if a government claims they are being used for riot-control purposes. While such chemicals are not subject to the same verification provisions as traditional chemical warfare agents like sulfur mustard or nerve agents, CWC members are required to declare their RCA holdings annually.

Since 2018, the United States has assessed that Iran is in non-compliance with the CWC due to incomplete declarations of its RCA stockpiles, alleged development of CNS-acting chemicals, and other compliance failures. In 2021, CWC states parties formally adopted a decision clarifying that the aerosolized use of CNS-acting chemicals—such as the opioid fentanyl and its analogues—for domestic law enforcement purposes is inconsistent with the convention and tantamount to the use of chemical weapons. In 2023, hackers leaked Iranian documents describing research by a university linked to the Islamic Revolutionary Guard Corps (IRGC) on filling a CNS-acting chemical into standard tear gas grenades.

In other words, if the Tehran regime used chemicals against protesters that caused prolonged harm—even if those chemicals were declared for a CWC-exempt riot-control purpose—such use may constitute the employment of chemical weapons.

Member states of the OPCW should press for a formal OPCW investigation in Iran. The United States could lead such an effort by providing any available evidence of the regime’s use of such chemicals to the OPCW.  

Iranian protesters and alleged victims can assist accountability efforts by safely preserving and submitting used gas canisters, grenades, or other munitions containing chemical residues to OPCW-designated laboratories for analysis. Healthcare providers can also play a critical role by preserving medical records of suspected victims of chemical weapons exposure.

Finally, Iranian regime defectors or individuals in positions of authority could provide crucial testimony or documentary evidence related to the use of chemical weapons.

The disturbing details that have emerged from the regime’s January massacre of Iranians reveal a government that has justified extreme violence to cling to power. Much like its former ally, Bashar al-Assad in Syria, the Tehran regime may view chemical weapons as a potent fear-and-force multiplier in its campaign of domestic repression. Investigating the regime’s reported use of chemical weapons is an essential step toward holding it accountable for these reprehensible acts.

About the Authors: Andrea Stricker and Gregory Koblentz

Andrea Stricker is deputy director of the Nonproliferation Program at the Foundation for Defense of Democracies. Prior to joining FDD in 2019, Andrea spent more than 12 years at the Institute for Science and International Security, authoring publications that integrated open-source research and analysis to detect and characterize nuclear proliferation and make policy recommendations to prevent it. Preceding that, she worked with the International Rescue Committee. Andrea is the co-author of Illicit Trade Networks Vol. 1: Connecting the Dots(2020), The Peddling Peril Indices (PPI)(2018 and 2019), Taiwan’s Former Nuclear Weapons Program(2018), and Revisiting South Africa’s Nuclear Weapons Program(2016) and has contributed chapters to The Plutonium Handbook, The Iran Primer, and Preventing Black Market Trade in Nuclear Technology. Her publications and analyses have appeared in such publications as The Washington Post, The Wall Street Journal, The New York Times, Associated Press, Los Angeles Times, Chicago Tribune, The Jerusalem Post, and ScienceMagazine. Follow her on X: @StrickerNonpro. 

Gregory D. Koblentz is an associate professor at George Mason University’s Schar School of Policy and Government and director of the Biodefense Graduate Program. He is also the editor-in-chief of The Pandora Report, an online newsletter that covers global health security, and the codirector of the Global BioLabs Initiative, which tracks high-containment labs and biorisk management policies worldwide. Koblentz is an associate faculty member at the Center for Security Policy Studies at George Mason. He is a member of the Scientist Working Group on Biological and Chemical Security at the Center for Arms Control and Non-Proliferation in Washington, DC, and the Security Working Group of the Engineering Biology Research Consortium (EBRC). In 2016, he briefed the United Nations Security Council on the impact of emerging technologies on the threat posed by nonstate actors armed with weapons of mass destruction.

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