Over 100 chemical weapons sites believed to remain in Syria after Assad’s fall

In recent months, Israel carried out airstrikes on some of Assad-era facilities suspected to have housed chemical weapons.

More than 100 suspected chemical weapons sites are believed to still exist across Syria, according to a report by The New York Times, citing the Organization for the Prohibition of Chemical Weapons (OPCW). The watchdog, which monitors global compliance with chemical weapons treaties, is now attempting to access the war-torn country to assess and dismantle what remains of the Assad regime’s notorious arsenal.

This is the first time the OPCW has publicly estimated the scale of Syria’s undeclared chemical weapons program since President Bashar al-Assad was toppled last year. The number—more than triple the 27 sites originally declared by the regime—is reportedly based on findings from outside researchers, humanitarian groups, and intelligence shared by member states, The New York Times reported.

These sites, scattered across Syria, are believed to have been involved in the research, production, or storage of weapons like sarin and chlorine gas, which Assad's forces repeatedly used on rebel-held areas and civilian populations throughout more than a decade of civil war. Sarin, a deadly nerve agent, and chlorine, a choking agent banned in warfare, were deployed in some of the conflict's most gruesome attacks, including the 2013 sarin gas assault on Ghouta.

The chemical weapons now represent a major challenge for Syria’s new caretaker government, led by Hayat Tahrir al-Sham (HTS), a group that has renounced ties to Al Qaeda but is still designated a terrorist organization by the United States. Experts have raised alarms over the possibility of these weapons falling into the hands of militant groups amid lingering instability and limited oversight in parts of the country.

In March, Syria’s foreign minister made a surprise appearance at the OPCW headquarters in The Hague, pledging to destroy any remnants of Assad’s chemical weapons program and to cooperate with international law. While this gesture has sparked cautious optimism among international observers, The New York Times noted that Syria has yet to appoint an ambassador to the OPCW—an important signal of commitment that remains missing.

The new government did allow a team from the OPCW to enter Syria earlier this year to begin preliminary documentation of the suspected sites. However, the risks remain high. Many of the suspected locations may be concealed in caves or remote areas, making them difficult to identify even with satellite imagery, experts told the newspaper.

Raed al-Saleh, head of the White Helmets (Syria Civil Defense), told The New York Times that “many locations… we don’t know about because the old regime was lying to the OPCW.” Other researchers, such as Nidal Shikhani of the Chemical Violations Documentation Center of Syria, said interviews with former Syrian scientists now in exile have revealed dozens of potential new sites.

In recent months, Israel carried out airstrikes on some of Assad-era facilities suspected to have housed chemical weapons. But it's unclear whether those operations destroyed actual stockpiles or merely damaged infrastructure—possibly contaminating the sites and obscuring critical forensic evidence.

Syria’s chemical weapons program began in the 1970s and was developed with the help of foreign-trained scientists, many of whom studied in Germany and other European countries. According to a former senior government chemist interviewed by The New York Times, the program's sophistication was far greater than what was ever disclosed to the international community.

The OPCW and allied humanitarian groups are now racing against time to locate and secure these sites—not only to eliminate potential threats but also to gather evidence that could be used in future prosecutions related to Assad-era war crimes.