Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, remain calm after clearing their M40-series protective masks during annual chemical, biological, radiological and nuclear training, Jan. 8, 201...

Spc. Brandon Goold, infantryman, Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, exposes himself to o-Chlorobenzylidene Malononitrile (tear gas) inside the range 72 gas chamber after removing his M40-ser...

Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, expose themselves to o-Chlorobenzylidene Malononitrile (tear gas) inside the range 72 gas chamber by removing their M40-series protective masks...

Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, await instructions while wearing an M40-series protective mask inside the range 72 the gas chamber during annual chemical, biological, radiolog...

Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, clear their M40-series protective mask of contaminants while inside the range 72 the gas chamber during annual chemical, biological, radiologic...

Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, clear their M40-series protective mask of contaminants while inside the range 72 the gas chamber during annual chemical, biological, radiologic...

Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, perform various exercises while wearing an M40-series protective mask inside the range 72 the gas chamber during annual chemical, biological, r...

Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, use the range 72 gas chamber for annual chemical, biological, radiological and nuclear training, Jan. 8, 2015. The gas chamber is a confined s...

Spc. Richard Azevedo(right) and Spc. Jonathan Soto (left), both infantrymen, Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, wait for their turn in the gas chamber during annual chemical, biological, rad...

Cpt. Michael Chavis, brigade medical planner, Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, breaths in clean air after exiting the gas chamber at range 72, Jan. 8, 2015. The gas chamber is a confined s...

Soldiers of Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, exit the gas chamber at range 72, Jan. 8, 2015. The gas chamber is a confined space used to expose Soldiers to tear gas to build confidence in ...

Spc. Brandon Goold, infantryman, Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, breaths in clean air after exiting the gas chamber at range 72, Jan. 8, 2015. The gas chamber is a confined space used to ...

The Soldiers, from Headquarters and Headquarters Company, 1st Stryker Brigade Combat Team, 4th Infantry Division, used a gas chamber located on range 72 for annual chemical, biological, radiological and nuclear training.

The gas chamber is a confined space where Soldiers are exposed to tear gas to build confidence in their M40-series protective masks.

Exposure to the gas causes a temporary burning sensation of the eyes, nose, throat, disorientation and difficulty breathing.

"The annual mask confidence chamber training is important because it gives soldiers confidence in their assigned equipment," said Sgt, 1st Class Kenneth Lexie, platoon sergeant and brigade CBRN NCO, 1st SBCT, 4th Inf. Div.

The mask will withstand a maximum of 15 nerve, choking, and blister agent attacks.

To validate the Raiders' ability to properly use their M40-series protective masks, CBRN specialists directed Soldiers to remove their mask from their face for five seconds before replacing it, expelling any gas trapped inside and then resealing the mask to their face.

While not required, some brave Soldiers removed their protective mask when asked fully exposing themselves to the gas and calmly walk out of the chamber.

"I definitely have confidence in my mask now," said Spc. Anna Vacheresse, information technology specialist, 1st SBCT, 4th Inf. Div.