Mustard Gas?

ISIS fighters may have fired a “mustard agent” at a US base near Mosul in northern Iraq, a Pentagon official said Wednesday. If confirmed, it would be the first chemical attack on U.S. forces in Iraq since they returned to the country in 2014.

http://www.foxnews.com/world/2016/09/21/isis-believed-to-have-attacked-us-base-in-iraq-with-chemical-agent.html