The World Failed to Disarm Syria. The Cleanup Starts Now.

Last week, Syria announced a multinational effort to locate and destroy its remaining chemical weapon supply -- the remnants of a program that the international community declared eliminated over a decade ago.

The problem is that nobody, including the Syrian government itself, knows quite what they are looking for, much less where it would be. More than 100 previously undeclared sites have been identified and flagged for inspection, but only 15 have been looked at. At the few sites inspectors have reached, they have found traces of nerve agents, buried barrels testing positive for chemical weapons material, and 75 cylinders of chemical precursors that vanished before anyone could check on them.

The original deal reached in 2013 between Damascus, Washington, and Moscow succeeded in removing and subsequently destroying some 1,300 metric tons of chemical weapons from Syria, which was progress. But the system rested heavily on what the Assad regime was willing to declare -- which, evidently, came down to what it was willing to turn over.

The Deal That Never Finished the Job

Back in August 2013, after a now-infamous attack on the Damascus suburb of Ghouta using sarin gas, the Obama administration came closer to direct military intervention against the Assad regime than at any other point.

President Obama had designated the potential use of chemical weapons as a "red line" a year prior, and Assad had just crossed it in a way that would prove difficult to ignore. Those strikes never materialized, though. Obama opted to seek congressional authorization first, a move that bought time for alternatives to emerge. Russia, sensing both an opportunity to shield an ally and a chance to position itself as a peacemaker on the world stage, eagerly came forward and presented its own proposal.

Under the terms of the deal, Syria would accede to the Chemical Weapons Convention, declare its stockpile, and hand everything over for destruction -- all of which it did, and American strikes were averted. Roughly 1,300 metric tons of declared agents and precursors were removed over the following months and neutralized abroad. Secretary of State John Kerry declared the removal "100 percent" successful, a line that Susan Rice echoed when she told NPR in January 2017 that the administration had gotten Syria to "voluntarily and verifiably give up its chemical weapons stockpile."

There were troubling signs from the outset, though. The OPCW flagged Syria's initial declaration as incomplete almost immediately, and over the next 11 years Damascus revised it around 20 times, each time acknowledging previously hidden elements of the program and never producing a document the OPCW was willing to call accurate.

The Obama administration, for its part, had every incentive to treat the deal as a success and move on. Pressing the OPCW's concerns would have meant reopening the crisis it had just spent considerable time and political capital resolving, while raising uncomfortable questions about whether the Russian-brokered alternative to military action had actually delivered what it promised.

The regime, in any case, was not waiting for inspectors to catch up. The Global Public Policy Institute documented 336 confirmed chemical weapons attacks in Syria between late 2012 and early 2019. Once the declared sarin and mustard stocks began to be shipped out, the regime shifted strategies and leaned more heavily on industrial chlorine, which cannot be banned outright because of its widespread applications. It began systematically dropping chlorine from helicopters across opposition-held areas in a campaign that would go on for years, partially masked by the legal grey area that chlorine use inhabits.

The regime would go on to prove it had not just kept the chlorine, either. In April 2017, Syrian forces hit the town of Khan Shaykhun with sarin, killing around 90 people and triggering retaliatory American cruise missile strikes within days. A year later, it did it again -- albeit this time with chlorine -- in Douma, killing 43 more and prompting the first joint US, British, and French military action against the regime over such use. The OPCW was later able to match the Khan Shaykhun sarin to precursor chemicals Syria had declared destroyed, confirming that the 2013 deal had left Assad with enough nerve agent to keep killing and enough delivery systems to do it with. Neither round of Western strikes stopped the program, and neither produced a serious effort to reopen the question of what the declaration had actually left in place. By that point, it was clear that the Russian-led disarmament effort had not been thorough.

By the time the regime finally collapsed in December 2024, what had been removed was what Assad was either willing to declare or pressured into admitting, and nothing else. Most of the issues the OPCW had raised with Damascus over more than a decade of inspections remained unresolved, and none of it generated the kind of political urgency that might have forced the issue back into the open.

This was undoubtedly a mistake. There remained -- and clearly, remains -- a significant stockpile of chemical weapons left in the country that simply cannot be accounted for, and the race is on for the Syrian government to dispose of it before someone else is able to get their hands on it.

The Missing Stockpile

That stockpile, whatever its true scale, sat undisturbed both through the regime's final years and since its fall. Throughout the regime's time in power, it had gone to great lengths to conceal the locations of its stockpiles from the international community, but also from many of its own officials.

When Bashar al-Assad fled for Moscow in December 2024, the program he left behind was inherited by a government that had no knowledge of how the system worked and, evidently, still has not discovered it.

"We don't know what's remaining," Syria's UN Ambassador Ibrahim Olabi said at the launch of a new international task force last week. "It was a secret program... The job is on Syria to basically look for these things and then declare them."

The OPCW, which has been trying to answer that question since gaining access in March 2025, has so far managed to visit only a fraction of the more than 100 previously undeclared sites it has identified. Teams have also examined more than 10,000 recovered documents alongside those site visits, with Syrian authorities continuing to hand over sealed boxes of records as they are discovered. Damascus is cooperating, but genuinely does not seem to know what it is working with.

But what inspectors have found at even that small share of locations and facilities has confirmed everyone's worst fears. At one undeclared facility, traces of a nerve agent were detected. In July 2024, the organization opened two entirely new outstanding cases after finding evidence of undeclared nitrogen mustard activity and traces of EA-1699 at locations Syria had sworn were never operational, pointing not to forgotten leftovers, but to production capabilities concealed from the beginning and never disclosed during 11 years of inspections. At other sites, inspectors found deteriorated barrels buried underground that tested positive for a chemical warfare agent and its degradation products.

Perhaps most concerning is the case of Aleppo, where inspectors back in January found storage containers for chemical precursors alongside internal paperwork documenting 75 cylinders that should have been present at the facility, but were nowhere to be found. At a nearby scrapyard, the team observed metal fragments that may have been pieces of the missing cylinders, but whether the contents had been safely disposed of or simply carted off by looters during the chaotic months after the regime's collapse is a question nobody can answer.

With more than 100 sites still unlisted, it is far from the only one -- and that is only the known sites. Experts who have tried to estimate the full scale of what is missing have arrived at numbers that dwarf what inspectors have found so far. Gregory Koblentz, who runs the Schar School's biodefense program at George Mason University and published an accounting of Syria's remaining arsenal in the Bulletin of the Atomic Scientists late last year, put the scale of what is unaccounted for at tens to hundreds of tons of undeclared nerve agent precursors, approximately 300 metric tons of sulfur mustard, and hundreds to thousands of chemical munitions.

The instinct might be to assume that materials hidden over a decade ago have long since degraded into irrelevance now, but the chemistry behind these compounds does not support that assessment. Syria stored its sarin and VX precursors in binary form, meaning the components were separated rather than pre-mixed, which significantly expands their shelf life.

There is historical precedent to back up these shelf lives, too. Sulfur mustard is notoriously persistent. UN inspectors in Iraq recovered caches that had been warehoused for more than 12 years and found them to still be highly potent.

All of which leaves Syria's new government, the OPCW, and a freshly assembled multinational coalition with a problem that was supposed to have been solved over a decade ago. Only now, the materials are scattered across a country whose own government is not aware of their locations, in quantities that can only be estimated.

The Race to Find It

Finding any of these leftovers would be a daunting task under ideal circumstances, given the scale of what is unaccounted for and how deliberately the Assad regime worked to ensure it stayed completely compartmentalized. Syria in March 2026, though, is about as far from ideal circumstances as can be imagined, and the situation on the ground there has been getting steadily worse for months.

The new government under Ahmed al-Sharaa has made genuine strides toward consolidating control over Syria's major cities, but its practical authority weakens considerably once you move beyond Damascus, Aleppo, and the handful of other urban centers where its security forces can operate with real confidence. That is particularly relevant given that the regime's most sensitive facilities were never concentrated in population centers. They were distributed across remote sites in the coastal, Alawite-heavy provinces around Latakia and Tartus.

Those provinces have become a hotbed for armed remnants of the old regime since Assad's departure, not random militias who might stumble across chemical precursors by accident, but experienced officers and fighters from the same security apparatus that concealed these weapons in the first place. The new government reasserted control over the major coastal cities and highways relatively quickly, but the mountainous rural terrain between them is another story. Cells tied to former regime intelligence and military units have been operating there since early 2025, conducting ambushes on government checkpoints, assassinating local officials, and generally sending a clear signal that Assad may be gone, but they are not.

Leaked recordings have linked some of these networks to exiled regime figures coordinating from Russia and Lebanon, and while the government has managed to contain each individual flare-up, it has not been able to stamp out the underlying insurgency. In areas most likely to contain hidden WMD stockpiles, that is exactly the wrong kind of problem to leave simmering.

And the security situation only deteriorates as you begin to look away from the coast. ISIS, which had largely gone quiet in the immediate aftermath of Assad's departure, has been rebuilding itself across central and eastern Syria, formally declaring war on the Sharaa government in February 2026 and backing it up with coordinated attacks on Raqqa and Deir ez-Zor. A suicide attack on a Damascus church last June was among the deadliest strikes on a civilian target since the regime fell. In the north, Turkish-backed factions have been documented by Human Rights Watch systematically looting civilian homes, land, and businesses across the territory they control.

These groups are clearly willing to go to great lengths to seize the regime's old stockpiles of whatever they can get their hands on. One monitoring group tracked nearly 2,900 separate incidents involving munitions and weapons platforms in just the first five months after Assad fled. There is no indication that any other group has been able to get its hands on chemical weapons yet, but the "yet" is doing quite a bit of heavy lifting. The longer those sites sit uninspected and the longer the former regime's chemical stockpiles remain up for grabs, the greater the risk that whatever is left over ends up in the hands of groups with malicious intent.

And at least one of those groups would not need to figure out what to do with chemical weapons if it got its hands on them. ISIS produced and deployed sulfur mustard during the civil war, loading it onto mortar shells and using it on the battlefield enough times that the OPCW formally attributed multiple attacks to the group.

When inspections are able to take place, though -- which is very much up in the air given the current situation in the region -- the historical record suggests that sending inspectors to comb through sites may not be the most effective way to find what is missing in the first place. David Kay's Iraq Survey Group is the closest comparison anyone has for this kind of work. Some 1,400 highly trained personnel, a budget of roughly a billion dollars, and 18 months of searching through ammunition storage points across Iraq after the 2003 invasion represented the "no stone left unturned" approach.

Kay's conclusion, though, was that this was far less effective than simply sitting down with the people who had built the programs in the first place and getting them to talk.

In Syria's case, that means tracking down the former employees of the Scientific Studies and Research Center, a 20,000-person organization that ran Syria's weapons development since the 1970s. Its chemical weapons division, Institute 3000, employed several hundred researchers who handled the science, while a parallel military unit called Branch 450, staffed by intelligence officers, managed storage, transport, and deployment entirely separately.

According to a post-fall dossier compiled by the Middle East Forum from insider testimony, the compartmentalization more or less ran in every direction. Researchers knew only their narrow piece of the science, military officers knew only the sites they were individually assigned to, and only a handful of figures at the top held anything close to a complete picture. Many of these figures are now dead or in exile.

There actually are some promising signs on that front. The international community has a decent idea of who some of these insiders are. Sanctions records, arrest warrants, and more than a decade of OPCW investigations have produced names, facility assignments, and in many cases hometown origins.

Identifying them and getting them into a room to disclose the locations of these stockpiles, though, are two very different things. The senior architects of the program -- the commander who oversaw storage and transport, along with the most senior scientists who ran production -- have largely vanished since Assad's fall. Some are believed to be under Russian protection in Moscow, others in Lebanon or the Gulf, others still potentially back in the coastal provinces. And while the OPCW has managed to interview some lower-level former employees who stayed in the country, the people who held anything even close to the full picture remain frustratingly inaccessible.

The multinational task force that launched last week carries the right mandate, and Syria's OPCW ambassador Mohammed Katoub, who survived the Ghouta sarin attack as a medical worker back in 2013, has become the public face of an effort that Damascus wants to deliver on.

But 15 months have already passed since the regime collapsed, and none of the problems outlined above are getting better with time. The world has solved this once before, but only at the cost of great effort spread over many years. Libya's chemical weapons elimination -- a program a fraction of the size of Syria's -- took over a decade to finish. With the state of affairs in Syria now, this one does not have that kind of time.

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