United States troops may have been moved to a hazardous area in Iraq recently, for a train-advise-and-assist team setup at a forward operating base near ISIS’s “front lines” not far from Mosul and an area that was the site of a chemical weapons attack not long ago — according to a U.S. military official.

It’s the Nineveh Operations Center in the “farming village” of Makhmour, and it’ll serve as a base for the U.S. to train and support the Iraqi’s planned attack on ISIS, in an effort to take back Mosul.

According to Iraq’s military, about 4,500 soldiers will be deployed to the area.

An area that may be littered with the remnants of poison — unorthodox chemical munitions that were dumped just days ago.

This from the Army Times:

Makhmour is along the edge of the Kurdish-controlled territory near the ISIS-held Tigris River valley and is near the site of a mustard gas attack last year and also a foiled ISIS attempt to launch chlorine gas rounds. A new mustard gas attack was reported in the area Wednesday.

Makhmour now has U.S. advisers as well as a team of U.S. troops providing force protection, Warren said. It’s also a new headquarters and command center for the Iraqi army’s 15th Division, a unit that participated in an American-led training program last year.

A defense official familiar with the attack said on Wednesday that the mustard-laden shells were not “danger close” to the operations center with U.S. troops.

While its unclear how many U.S. troops are in this specific region, it is known that there are about 3,700 American military service members deployed throughout the splintered country.