Kurdish forces in Iraq have accused ISIS of using chemical weapons, including chlorine, during fighting on Dec. 26, 2014, and Jan. 23 and 28 of this year, reports say. From the AP:
"I put a wet scarf on my face because when I saw the gas, I felt it," said Capt. Mohammad Sewdin, who leads the Kurdish special forces unit targeted in the December attack. "I was afraid it might be something like (chemical weapons). So I told my men to do the same."
Sewdin told The Associated Press he was temporarily blinded for six hours after the attack and coughed up blood. He and others were hospitalized.
The accusations have not yet been verified by “international authorities,” the AP says. Iraqi forces have also previously accused ISIS of chemical weapons use. Syrian dictator Bashar al-Assad has perpetrated documented chemical attacks that have killed civilians during his war with rebel groups including ISIS, though in 2013 he agreed to destroy his chemical weapon arsenal.
The use of chemical weapons in warfare is banned by an international treaty that describes them as weapons of mass destruction, though ISIS has of course demonstrated its indifference to rules of combat via a number of other brutal practices.