The Islamic State in Iraq and Syria is suspected of firing a chemical weapon at a base where U.S. troops were operating.

CNN reported that ISIS troops are believed to have shot a shell with a mustard agent at the Qayarrah air base in northern Iraq on Tuesday.Officials characterized the shell as either a rocket or artillery shell. After it landed on the base, U.S. troops tested it and received an initial reading for a chemical agent they believe is mustard.

One official told CNN the agent had “low purity” and was “poorly weaponized.” A second official said it was “ineffective.”

No U.S. troops were hurt or have displayed symptoms of exposure to a mustard agent.

The substance is now being sent to a lab for further examination, according to the report.

The U.S-led coalition recently bombed a building believed to be a chemical weapons making facility near Mosul.

Several hundred US troops are current using the base as a staging area for supporting Iraqi forces.

Source: thehill.com