Investigators from the global chemical weapons agency have found the Syrian regime responsible for a poison gas attack that killed 43 people in a suburb of Damascus in 2018, leaving victims choking to death in the basement of a home.
In a report nearly five years in the making, the Organisation for the Prohibition of Chemical Weapons (OPCW) found the canisters carrying poison gas had been dropped by a Syrian air force helicopter over Douma – then one of the last opposition strongholds near the Syrian capital.
The attack took place on 7 April 2018, as the years long war wound down and Syrian forces attempted to remove rebels and their supporters from the area. The cylinders had carried high concentrations of chlorine, at least one of which dispersed its deadly payload into a ground floor room where civilians had been taking shelter.
Another cylinder was left embedded in the roof of a nearby building, having clearly fallen from a height.
The report was based on 70 environmental samples as well as 66 witness statements and technical data that simulated the trajectory of the cylinders and disbursement of gasses. Investigators had tried to access Douma in the days after the attack, but were kept at bay as regime troops conducted a clean up of the area.
In the immediate aftermath, witnesses spoke openly about the number of casualties and the injuries they had sustained, as well as the pungent smell of chlorine. But that candour was soon replaced by silence, as officials warned of consequences for speaking out, and a cast of people emerged, claiming those who had died may have suffered from hypoxia, or had instead poisoned themselves.
The OPCW said it had “reasonable grounds to believe” that at least one helicopter attached to the elite Tiger Force had been involved, adopting the language it had used in earlier investigations into chemical attacks committed in Syria once it felt a threshold of proof had been met.
At the time, the government of Bashar al-Assad denied having used chemical weapons, maintaining a line it had stuck to throughout the war. Barrel bombs containing chlorine and dropped from helicopters had been a frequent fixture at the peak of the conflict, but the death tolls from those rarely neared the number killed in the Douma attack, as few had taken place in densely packed areas.
International investigators, including the OPCW had also blamed the Syrian government for using the more deadly chemical weapon Sarin in a spate of attacks, including a strike on the outskirts of Damascus in August 2013 and another in the northern town of Khan Sheikhun in 2017. Both areas were opposition strongholds and in each case, Syrian officials blamed rebels for gassing themselves and using actors to embellish the scene.
“The use of chemical weapons in Douma – and anywhere – is unacceptable and a breach of international law,” said the director general of the OPCW, Fernando Arias, after the release of the report on the 2018 attack. “The world now knows the facts – it is up to the international community to take action, at the OPCW and beyond.”
With fighting largely subdued in much of Syria, Assad now presides over a rump of a state. The north-west is controlled by jihadist factions and opposition groups and is home to nearly four million people, many of them displaced. The north-east, meanwhile, is under the aegis of Kurdish groups, which are supported by Russia and enabled by the US to continue fighting Islamic State in Syria’s eastern deserts.
Southern Syria remains volatile, while Damascus faces an energy and financial crisis in which even supporters of the regime have been struggling to meet their subsistence needs.
• This article was amended on 30 January 2023. The OPCW is the Organisation for the Prohibition of Chemical Weapons, not the Organisation for the Prevention of Chemical Weapons.