This may stand as the definitive article on the OPCW-Douma scandal. From Aaron Maté at thegrayzone.com:
Facing accusations that it issued a doctored report alleging a chemical attack in Syria, the OPCW has released an inquiry attacking two whistleblowers as rogue actors. Leaked documents obtained by The Grayzone reveal serious distortions in the OPCW inquiry as well as a campaign of intimidation against internal dissenters.
For the past year, the Organization for the Prohibition of Chemical Weapons (OPCW) has been roiled by allegations that it manipulated an investigation to falsely accuse the Syrian government of a chemical weapons attack. An OPCW report released in March 2019 lent credence to claims by Islamist militants and Western governments that the Syrian military killed around 40 civilians with toxic gas in the city of Douma in April 2018. The accusation against Damascus led to US-led military strikes on Syrian government sites that same month.
But leaked internal documents published by Wikileaks show that OPCW inspectors who deployed to Douma rejected the official story, and complained that higher-level officials excluded them from the post-mission process, distorted key evidence, and ignored their findings.