Syrian government troops were responsible for two toxic gas attacks and Islamic State militants used sulphur mustard gas, a joint investigation by the United Nations and the global chemical weapons watchdog has finally found.
The year-long UN and Organisation for the Prohibition of Chemical Weapons (OPCW) inquiry – unanimously authorised by the UN Security Council – focused on nine attacks in seven areas of Syria, where a separate OPCW fact-finding investigation had already determined that chemical weapons had likely been used.
Eight of the attacks investigated involved the use of chlorine. The inquiry was unable to reach a conclusion in six cases, though it said that three of those cases warranted further investigation.
The excuse for dilly-dallying are over. The Security Council should now impose sanctions and take other strong measures against the Syria regime in the wake of the inquiry.
The 15-member Security Council is due to discuss the report on Tuesday.
The inquiry found there was sufficient information to conclude that Syrian regime helicopters dropped devices that then released toxic substances in Talmenes on April 21, 2014 and Sarmin on March 16, 2015, both in Idlib governorate. Both cases involved the use of chlorine.
It also determined there was sufficient information to conclude that Islamic State militants were the “only entity with the ability, capability, motive and the means to use sulphur mustard gas in Marea on 21 August, 2015”.
The Chemical Weapons Convention prohibits the development, production, stockpiling, transfer and use of chemical weapons and requires states parties to destroy chemical weapon stockpiles. The use of prohibited weapons such as chemical weapons is a war crime under customary international law.
Syria agreed to destroy its chemical weapons in 2013 under a deal brokered by Moscow and Washington. The Security Council backed that deal with a resolution that said in the event of non-compliance, “including unauthorised transfer of chemical weapons, or any use of chemical weapons by anyone” in Syria, it would impose measures under Chapter 7 of the UN Charter.
Chapter 7 deals with sanctions and authorisation of military force by the Security Council. The body would need to adopt another resolution to impose targeted sanctions – a travel ban and asset freeze – on people or entities linked to the attacks.
However, Russia and China have previously protected the Syrian government from council action by blocking resolutions, including a bid to refer the situation in Syria to the International Criminal Court. The council must now demonstrate a robust response to the report. 
In the case of the attack in Sarmin, the UN/OPCW inquiry found that the remnants of the device dropped “are consistent with the construction of a barrel bomb”. Barrel bombs are steel drums full of shrapnel and explosives dropped from the air.