Time line of investigations into Syria’s chemical weapons

• 2013 – US Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov reach an agreement on the elimination of Syria’s chemical weapons.

– UN Secretary General Ban Ki-moon establishes the UN Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic. Headed by Swedish scientist Ake Sellstrom and comprised of experts from the World Health Organization and the Organization for the Prohibition of Chemical Weapons (OPCW), it is tasked with looking into possible use of such weapons following reports of an attack in the northern town of Khan al-Assal. It confirms use of sarin gas in the August 21 attack in the Damascus suburb of Ghouta that killed hundreds.

(All 192 parties to the 1997 Chemical Weapons Convention are automatically members of the OPCW, which is therefore constituted of virtually all UN member states. Israel is the only country that has signed without ratifying the agreement; Egypt, North Korea and South Sudan have neither signed nor ratified.)

• 2014 – OPCW Declaration Assessment Team begins work to resolve gaps and inconsistencies in Syria’s declaration to the OPCW, which was supposed to include all aspects of its chemical weapons program. By April 2018, after visiting Syria at least 18 times to inspect sites and meet Syrian officials, the technical secretariat of the OPCW remained unable to “verify that Syria had submitted a declaration that could be considered accurate and complete.”

– OPCW establishes a fact-finding mission in response to persistent allegations of chemical weapon attacks in Syria, “to establish facts surrounding allegations of the use of toxic chemicals, reportedly chlorine, for hostile purposes in the Syrian Arab Republic.” The mission concludes the use of chlorine was systematic and widespread. It is not tasked with assigning blame.

• 2015 – UN-OPCW Joint Investigative Mechanism (JIM) in Syria is established to identify individuals or entities behind chemical weapons attacks.

• 2016 – JIM concludes that Syrian government forces used chlorine as a chemical weapon in three cases and that Islamic State militants used sulfur mustard.

– OPCW executive council adopts decision condemning Syrian government and Islamic State for chemical weapons use after a vote that split the body and signaled an end to US-Russia cooperation.

• 2017 – OPCW fact-finding mission concludes that sarin was used in an April 4 attack in the Khan Sheikhoun area of northern Syria, the most deadly use of the nerve agent in three years. It does not assign blame.

– The Syrian government of President Bashar al-Assad is blamed by JIM for that attack which killed dozens of people.

– Russia casts a veto at the UN Security Council preventing the renewal of the mandate for JIM. The investigation ends in November 2017 after Russia repeatedly blocks attempts at renewal.

– OPCW chief announces destruction of over 96% of the world’s declared chemical weapons.

• 2018 – Diplomats and scientists tell Reuters that the Syrian government’s chemical weapons stockpile has been linked for the first time by lab tests to the largest sarin nerve agent attack of its civil war.

Laboratories working for the OPCW compared samples taken by a UN mission in the Damascus suburb of Ghouta after the August 21, 2013 attack to chemicals handed over by Damascus for destruction in 2014.

The tests found “markers” in samples taken at Ghouta and at the sites of two other nerve agent attacks, in Khan Sheikhoun in April 2017 and Khan al-Assal in March 2013, two people involved in the process say. (Reuters)