Does Iran Have Chemical Weapons? What the Record Shows

Not one it admits to, but Washington says one exists in a narrow form. In July 2025, the U.S. delegation told the Organisation for the Prohibition of Chemical Weapons (OPCW) that Iran is “in violation of the Convention,” both for incomplete declarations and for developing “pharmaceutical based agents for offensive purposes as part of an active chemical weapons program.”

These are drugs that act on the central nervous system. They are meant to disable people, though in a large enough dose they kill. The U.S. statement cited leaked Iranian documents showing a military university developing grenades to spread medetomidine, a veterinary sedative. The 2024 U.S. intelligence threat assessment said Iran “probably aims to continue research and development of chemical and biological agents for offensive purposes.”

Iran rejects all of it. In a July 2026 statement to the OPCW Executive Council, its delegation said every chemical facility in Iran is under the OPCW’s verification regime, that the Technical Secretariat has consistently confirmed their peaceful nature, and that the United States has “never presented any evidence” for its charges. No OPCW body has adopted a finding that Iran broke the treaty; the charge is Washington’s.

Yes, by its own account. In 1998, a year after joining the convention, Iran told the OPCW for the first time that it had built chemical weapons capabilities in the last phase of the war with Iraq, and said the program ended when the war did. Its initial declaration, filed in parts in 1998 and 1999, listed its former production facilities.

The United States says that declaration was incomplete. At the OPCW review conference on November 22, 2018, U.S. Ambassador Kenneth Ward named three gaps. Iran never declared chemical artillery shells it sent to Libya in the 1980s, found after Muammar Gaddafi’s fall in 2011 in boxes marked in Farsi. Iran never declared its stocks of the riot-control agent CR, even though it had marketed CR and its delivery systems at arms fairs. And Iran never declared a facility for filling munitions with agent, which the United States says it must have had, given the filled shells and bombs found in Libya and Iranian-origin chemical mortar rounds found in Iraq by U.N. inspectors.

Because Iran was the main victim of chemical warfare in the late 20th century. Iraq first used mustard gas against Iranian troops in 1983, and in March 1984 it fired the nerve agent tabun, the first battlefield use of a nerve agent anywhere. United Nations teams sent to the front in the mid-1980s confirmed both agents.

The attacks reached civilians too. On June 28, 1987, Iraqi aircraft dropped mustard bombs on the Kurdish town of Sardasht in northwestern Iran, killing about 130 people and injuring thousands. Iranian officials cite those years whenever the charge comes up, and survivors’ groups from Sardasht still address OPCW conferences in The Hague.

A site the OPCW does not inspect. Israel struck the Shahid Meisami Group in Karaj, west of Tehran, on June 15 and 16, 2025, during the 12-day war. Israel told the OPCW the complex works for Iran’s defense ministry under its research arm, SPND, and that the strike left it unusable. Iran said the group makes chemical-defense equipment.

At an emergency Executive Council meeting called by Iran on July 1, 2025, OPCW Director-General Fernando Arias said the building that was hit “is not a declared facility,” so his inspectors have no mandate to monitor it. A declared Iranian chemical site and Iran’s OPCW-designated laboratory sit nearby; Arias said he knew of no harm to the laboratory. The United States had already sanctioned the Shahid Meisami Group and its head, Mehran Babri, on December 3, 2020, for testing and producing incapacitating agents at SPND’s request.

Nobody on the record has shown that it has. The November 2026 warning claimed Iran was moving to fit chemical agents to missiles or drones, but neither Israel nor the United States has published evidence, and Iran has dismissed the accusation as psychological warfare. Filling a warhead with agent is the simpler step; spreading it effectively over a target is much harder.

What the public record supports is narrower: an alleged program for incapacitating agents, past undeclared transfers and holdings, and a disputed research site. That is a treaty dispute, not proof of a battlefield arsenal like the one Iran faced from Iraq. Iran’s missile and nuclear files carry far more documented evidence, as our report on Pickaxe Mountain shows.