“Chemical weapons experts have determined that mustard gas was used in a Syrian town where Islamic State insurgents were battling another rebel group, according to a report by an international watchdog seen by Reuters. A confidential Oct. 29 report by the Organization for the Prohibition of Chemical Weapons (OPCW), a summary of which was shown to Reuters, concluded “with the utmost confidence that at least two people were exposed to sulfur mustard” in the town of Marea, north of Aleppo, on Aug. 21.”
“…Sulfur mustard – which causes severe delayed burns to the eyes, skin and lungs – is a so-called Schedule 1 chemical agent, meaning it has few uses outside warfare.” (Coordination Cell)

http://www.reuters.com/article/2015/11/05/us-mideast-crisis-syria-chemicalweapons-idUSKCN0SU2PZ20151105?feedType=RSS&feedName=topNews##0fgtKyq61ESKhVp7.97