Syria's new authorities and international inspectors have uncovered dozens of previously undeclared chemical weapons stockpiles across the country, revealing the true scale of a programme that the Assad government long denied and concealed. The Organisation for the Prohibition of Chemical Weapons (OPCW), the international watchdog based in The Hague in the Netherlands, confirmed that its experts worked alongside Syrian authorities in May to locate and secure munitions, precursor materials, mixing and storage equipment, and thousands of pages of documents related to the former regime's chemical weapons programme.

The discoveries were made in areas around Hama, Homs, and Latakia — cities in central and western Syria that served as strongholds of Bashar al-Assad's government during the country's civil war. Among the items found were munitions bearing similarities to those used in the Ghouta chemical attack of August 2013, which killed more than 1,400 civilians, and attacks in the towns of Ltamenah and Khan Shaykhun in 2017. OPCW Director-General Fernando Arias stated that the findings confirm the organisation's longstanding assessment that the Assad government withheld information about the true extent of its chemical weapons programme. Syrian Foreign Minister Asaad al-Shaibani, writing on the social media platform X, described the results as the fruit of months of national, intelligence, and technical work, and said all secured materials would be transferred to specialist facilities for destruction.

Syria formally joined the OPCW in September 2013, following the Ghouta massacre, and a joint UN-OPCW mission declared it had destroyed Assad's declared stockpiles by August 2014. However, it subsequently emerged that only weapons at sites reported by the regime had been eliminated. Syrian forces went on to carry out further attacks using chlorine and sarin gas in multiple cities, including Aleppo and Douma. In April 2021, OPCW member states voted to suspend some of Syria's membership rights after the organisation confirmed the use of chemical weapons in Ltamenah in 2017 and Saraqib in 2018.

Since Assad's fall in December 2024, the new Syrian leadership has pledged full transparency and cooperation with the OPCW, reactivating its permanent mission to the organisation in November 2025. Syrian authorities say 18 people linked to the former regime's chemical weapons programme have been arrested, including senior military officers, former technical experts, and members of the security apparatus. The Syrian Network for Human Rights has documented 217 chemical attacks carried out by Assad's forces since the start of the uprising in 2011. The latest disclosures underscore how systematically the former government concealed its capabilities — and the scale of the accountability challenge now facing Syria's transitional authorities.