Following the August 2013 Ghouta chemical attack , Syria , which had long been suspected of possessing chemical weapons , acknowledged them in September 2013 and agreed to put them under international supervision . On 14 September Syria deposited its instrument of accession to the CWC with the United Nations as the depositary and agreed to its provisional application pending entry into force effective 14 October . An accelerated destruction schedule was devised by Russia and the United States on 14 September , and was endorsed by United Nations Security Council Resolution 2118 and the OPCW Executive Council Decision EC-M-33 / DEC. 1 . Their deadline for destruction was the first half of 2014 . Syria gave the OPCW an inventory of its chemical weapons arsenal and began its destruction in October 2013 , 2 weeks before its formal entry into force , while applying the convention provisionally . All declared Category 1 materials were destroyed by August 2014 . However , the Khan Shaykhun chemical attack in April 2017 indicated that undeclared stockpiles probably remained in the country . A chemical attack on Douma occurred on 7 April 2018 that killed at least 49 civilians with scores injured , and which has been blamed on the Assad government
Ghouta chemical attack
Ghouta chemical attack
Chemical Weapons Convention