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-series protective masks during annual chemical, biological, radiological and nuclear training, Jan. 8, 2015. Exposure causes a temporary burning sensation of the eyes, nose, throat, disorientation and difficulty breathing.