By John Erath
Since 1993, chemical weapons have killed thousands, with many times more affected, often suffering for years. This despite the Chemical Weapons Convention ban on such activity and a general view that such weapons have little military utility and too high a risk of harm to civilians. During that time, the Organization for the Prevention of Chemical Weapons, the OPCW, has led international efforts to halt chemical weapons use. The OPCW has done valuable work, including in Syria and Ukraine to identify users of chemical weapons and put a stop to their production before use. The good work is now in jeopardy because the United States has not paid its contribution.
Funding the OPCW is clearly in the U.S. interest as it has time and again kept chemical weapons from falling into the hands of terrorists who would have little hesitation about using such weapons against Americans. OPCW has traditionally enjoyed strong bipartisan support in Washington, so this is not about politics. Rather, the OPCW appears to have been caught in general skepticism about international organizations. It deserves better.
Greg Koblenz, a member of the Center’s Scientists Working Group on Biological and Chemical Security has written a letter, co-signed by 18 leading experts on chemical weapons and non-proliferation from across the political spectrum, on the importance of funding the OPCW. The letter is addressed to Secretary of State Rubio and reads as follows:
Dear Mr. Secretary and National Security Advisor Rubio,
International efforts to reduce the threat posed by chemical weapons are being endangered by the failure of the United States to pay its annual contribution to the Organization for the Prohibition of Chemical Weapons (OPCW), the international organization charged with implementing the 1993 Chemical Weapons Convention that bans the production and use of chemical weapons. Full and effective implementation of the Chemical Weapons Convention (CWC) is vital to U.S. national security.
The CWC has historically enjoyed strong bipartisan support in the United States. The treaty was drafted during the Ronald Reagan and George H.W. Bush administrations and ratified by the Republican-controlled Senate in 1997. The OPCW won the Nobel Peace Prize in 2013 for its intensive efforts to eliminate chemical weapons.
The United States, the largest contributor to the OPCW, has not paid the $17 million it owes for 2026. To put that amount into perspective, the overdue payment is one-fifth of the OPCW’s annual budget of $90 million, which the United States voted in favor of last year.
As a result of the lack of timely payment by the United States, the OPCW’s independent financial advisory board has warned that the organization is in a “precarious” financial situation and faces the “unprecedented circumstance” of having to cancel or postpone routine activities like inspections and verification missions. These are strong words from otherwise mild-mannered accountants. In July, the accountants predicted that these cancellations and postponements could start as early as mid-August so the OPCW may have already started curtailing its operations due to this funding crunch.
This is no time to shortchange the OPCW. We, the undersigned nonproliferation and national security experts, urge the United States to pay its assessed contribution as soon as possible to avoid any disruption to the OPCW’s activities, which are vital to our own security.
The global chemical weapon landscape remains complex and challenging. The OPCW is currently engaged in operations in Syria and Ukraine and new missions involving Sudan and Cambodia/Thailand are on the horizon.
In Syria, the OPCW is finally making progress locating, securing, and destroying the remnants of the Assad regime’s chemical weapons program. In May, OPCW experts confirmed the discovery of dozens of Assad-era chemical weapons and in August they began supervising Syria’s destruction of these weapons. So far, just over half of these weapons have been destroyed while Syrian teams and OPCW inspectors search the country for more. The OPCW has also undertaken training missions to build the capacity of the Syrian government to find, secure, and destroy chemical weapons left over from the Assad regime.
Russia continues using chemicals as weapons against Ukraine at an unprecedented scale with almost 14,000 reported incidents since Russia’s full-scale invasion in 2022. The United States and multiple European governments have accused Russia of using riot control agents and chloropicrin, a World War I-era vomiting agent, on the battlefield in Ukraine. The OPCW has deployed teams five times to Ukraine to investigate Russia’s use of chemical weapons and confirmed Ukrainian allegations that riot control agents have been used on the battlefield. The OPCW has also trained Ukrainian experts in the detection of chemical warfare agents, how to safely collect and transport chemical samples, and how to respond to the use of toxic chemicals.
Recent reports of chemical weapon use by Sudan and Thailand could place new demands on the OPCW that are not covered by its regular budget.
Since the United States first accused Sudan in May 2025 of using chemical weapons against the Rapid Support Forces (RSF) as part of that country’s civil war, credible evidence has recently emerged that strongly supports this allegation. According to these sources, Sudan used chlorine-filled cylinders in at least two attacks in September 2024 and produced a stockpile of aerial bombs designed to disperse chlorine gas. Earlier this month, Cambodia filed a complaint with the OPCW alleging that Thailand had used unspecified chemical weapons during a 2025 border skirmish.
The allegations regarding Sudan and Thailand could potentially trigger an investigation of alleged use, a technical assistance visit, or, in the case of Sudan, a challenge inspection of suspected chemical weapon facilities. Any of these deployments would place new demands on the OPCW’s inspectors and laboratory.
We urge you to direct that the administration deliver the United States full assessed contribution for the OPCW’s vital work by the start of the next Executive Council session on October 6.
Respectfully,
Philipp C. Bleek, Professor, Middlebury Institute of International Studies at Monterey
Stefano Costanzi, Professor of Chemistry and Policy, American University
Nancy D. Connell, Professor Emerita, Rutgers New Jersey Medical School
John Erath, Senior Policy Director, Center for Arms Control and Non-Proliferation
Anemone Franz, Visiting Research Fellow, American Enterprise Institute
Col. (ret) John A. Gilbert, Senior Science Fellow, Scientists Working Group on Chemical and Biological Security, Center for Arms Control and Non-Proliferation; former Chief of the Chemical Inspection Division, On-Site Inspection Agency (now Defense Threat Reduction Agency), Department of Defense
Natasha H. Hall, former Community Engagement Director, Mayday Rescue
Dan Kaszeta, Fellow of the Royal Historical Society
Daryl G. Kimball, Executive Director, Arms Control Association
Jeffrey W. Knopf, Professor, Monterey Institute of International Studies
Gregory D. Koblentz, Associate Professor & Director, Biodefense Graduate Program, George Mason University
Margaret E. Kosal, Professor, Sam Nunn School of International Affairs, Georgia Institute of Technology
Albert J. Mauroni, former director, US Air Force Center for Strategic Deterrence Studies
Christina McAllister, Partnerships in Proliferation Prevention Program Director, Henry L. Stimson Center
Amb. (ret) Robert Mikulak, former U.S. Permanent Representative to the OPCW
Saskia Popescu, Adjunct Faculty, Biodefense Graduate Program, George Mason University
Mallory Stewart, Chief Executive Officer, Council on Strategic Risks
Andrea Stricker, Deputy Director, Nonproliferation Program, Foundation for Defense of Democracies
Paul F. Walker, Chair, Chemical Weapons Convention Coalition; Vice Chair, Arms Control Association
*Affiliations are for identification purposes only. The views expressed are those of the signatories in their personal capacity and do not necessarily represent the views or positions of their respective institutions.
CC: Senator Dave McCormick, SFRC; Senator Rand Paul, SFRC; Senator Tammy Duckworth, SFRC; Senator Chris Coons, SFRC; Senator Tim Kaine, SFRC; Congressman Ryan Mackenzie, HFAC; Congressman Michael Baumgartner; Congressman Mike McCaul, HFAC; Congressman Greg Meeks, HFAC; Congresswoman Sara Jacobs, HFAC; Congressman Gabe Amo, HFRC; Congresswoman Sarah McBride; and Congressman Mark Pocan
As the letter states, it is time to act and release the funding for the OPCW. State’s own FY26 and FY27 budget justifications cite OPCW as important for U.S. national security. This has not changed.
This is not a political matter. It is a case of U.S. interest. Let’s hope the administration does the right thing.
