It was assessed that up to 75 people were killed in Douma on 7 April 2018, with as many as 500 further casualties. All indications were that a chemical weapons attack had taken place. UK medical and scientific experts analysed reports, images and video footage from the incident and concluded that the victims had been exposed to a toxic chemical, which was corroborated by first-hand accounts from NGOs and aid workers. The World Health Organisation received reports that hundreds of patients arrived at Syrian health facilities with "signs and symptoms consistent with exposure to toxic chemicals". A significant body of information, including intelligence, indicated that the Syrian regime was responsible for the attack using barrel bombs dropped from helicopters.
A subsequent thorough investigation by the Organisation for the Prohibition of Chemical Weapons (OPCW) found reasonable grounds to conclude that use of a toxic chemical as a weapon, likely molecular chlorine, had taken place. We expect further investigation in due course by the OPCW Investigation and Identification Team to focus on identifying those responsible.