US officials say they are conducting initial tests tonight after an ISIS rocket attack against the Qayara base, intended to be the main staging area for forces attacking Mosul in the next few weeks, was believed to have contained chemical agents.
The rocket attack came within a few hundred meters of US forces on the ground, but no one was wounded. Troops say an initial sample of a substance left behind at the site tested positive for mustard agents, though they said the second test was negative.
The troops who were nearby have undergone decontamination procedures which would be done if they were exposed to mustard gas, but officials say they have yet to see anyone come down with any symptoms related to the incident. ISIS has been known to have some limited ability to produce primitive chemical weapons, including mustard gas.
This result is not uncommon for ISIS chemical attacks, as by and large they’ve caused limited injuries and almost no deaths. The value of the weapons is primarily the fear that the notion of being attacked by chemical weapons inspires, and it is believed by many that ISIS will launch more such attacks as the Mosul battle approaches.