U.S. expects Islamic State to wield chemical weapons in Mosul fight

In a previously undisclosed incident, U.S. forces confirmed the presence of a sulfur mustard agent on Islamic State munition fragments on Oct. 5, a second official said. The Islamic State had targeted local forces, not U.S. or coalition troops.
"Given ISIL's reprehensible behavior and flagrant disregard for international standards and norms, this event is not surprising," the second official told Reuters, speaking on condition of anonymity, and using an acronym for Islamic State.
http://www.reuters.com/article/us-mideast-crisis-iraq-chemicalweapons-idUSKCN12I2WZ?