Some 8,000 soldiers with the 4th Infantry Division were accidentally tear-gassed the day before Thanksgiving during a massive physical morale event in which soldiers scaled obstacles, went through trenches and ran up hills.
Division leadership overseeing the event at Fort Carson, Colorado, marked the boundaries of the course with tear gas, an unusual use of the chemical irritant given it can easily move with the wind.
The gas did shift with the wind on Nov. 23, settling on soldiers who were not told ahead of time they would be gassed. They did not have gas masks, a standard requirement for any time chemical irritants are deployed in training.
"The purpose of this event was to build unit cohesion. Leaders at echelon participated in this event with Soldiers," Dee McNutt, a Fort Carson spokesperson, told Military.com in a statement. "The limited use of CS [gas] was not intended to interfere with the formations but to deter participants from leaving the course."
Troops are often informed ahead of time about whether they may be exposed to tear gas as a safety precaution. Army guidance instructs that soldiers should not wear contact lenses, given the gas can get trapped between that and the eye, causing severe pain. Pregnant soldiers are also advised not to be exposed to tear gas due to possible health risks; there is some evidence that exposure to tear gas can increase the risk of a miscarriage.
The event was intended to honor the Battle of Dak To, a Vietnam engagement composed of elements from the 4th Infantry Division, in which 361 U.S. soldiers were killed. Fort Carson had two other similar events, one in November last year and one in May honoring the 4th Infantry Division's actions in World War II in Huertgen Forest and on Utah Beach.
"These events are meant to have aspects of the unknown, replicating historical combat events in previous battles," McNutt said.
-- Steve Beynon can be reached at Steve.Beynon@military.com. Follow him on Twitter @StevenBeynon.