You mean the chemical weapons confirmed by both the NYT and the international Organization for the Prohibition of Chemical Weapons?
https://www.nytimes.com/2014/10/24/world/middleeast/question...
https://www.nytimes.com/2014/11/23/world/middleeast/thousand...
https://www.nytimes.com/2015/02/16/world/cia-is-said-to-have...
https://www.nytimes.com/interactive/2014/12/03/world/middlee...
https://www.nytimes.com/interactive/2014/10/14/world/middlee...