FORT SILL, Okla. -- Soldiers in A Battery, 1st Battalion, 19th Field Artillery lined up against the gas chamber wall April 15. While their bravado may have lasted throughout the rest of the training, with their gas masks on their eyes reflected a certain fear of the unknown.

A group of Soldiers filed inside the building leaving the rest to wonder their fate. Once the outgoing door cracked open for the first time, those Soldiers had no doubt, the effects of the CS gas were written all over their faces.

Teary eyes, snot and drool adorned the fronts of their Mission Oriented Protective Posture gear. Some threatened to vomit, but few actually did. The physical effects had taken over and many had done exactly what the drill sergeants told them not to do rub their eyes.

With one arm extended out to the Soldier in front of them they walked the length of the building and began the ritualistic flapping of their arms. As they released the gas from their suits and their skin, the side effects slowly dissipated, leaving only clean up.

The active ingredient, CS, is one of a group of chemical compounds called lachrymators. These chemicals are tear producing agents, hence the euphemism \'tear gas.' Exposure to them causes severe eye irritation, a profuse flow of tears, skin irritation and irritation of the upper respiratory tract, causing sneezing, coughing and difficulty in breathing.

"It was horrible. The drill sergeants told us to open our eyes and I told him 'I can't, I can't.' I wanted to throw up," said Pfc. Derrick Glass.

While admitting that most of the exercise was mental, his battle buddy looked at the positive.

"It's a good experience for everybody because it gives us something to look back on. A tough experience like that really strengthens you, showing that you can go through it," said Pvt. Joe Farrel.

The trainees recently started the transformation from civilian to Soldier, and they received the bittersweet lesson early on. In just their second week of training they headed to the gas chamber where they learned how to properly don their gas masks in nine seconds.

"You've got to close your eyes. Stop breathing, put your gas mask on. Pull the head harness over your head and then clear and seal," said Drill Sergeant (Sgt. 1st Class) Sharon Liehr.

While inside the gas chamber the trainees were instructed to pull their masks off for a few seconds, put it back on and clear and seal it once again.

The cadre of the gas chamber said essentially Soldiers are their own worst enemy while enduring the exercise and they have seen it all.

"Once you give the cadre a thumbs up you're going to execute a left face. At this time some of you have the urge to run. I don't know why you always do it at this time. You get a little taste of that CS and you run off. Do not run out. If you need to, clear and seal your mask as many times as you want," said Sgt. John Jones, Company C, 434th Field Artillery Detachment.

Before they stepped into the chamber the trainees went through situational exercises such as reacting to an NBC attack, and how to treat someone they believed has been exposed.

"It teaches them confidence. It gives them confidence in their mask and it teaches them that if there ever comes a time something like this happens they'll be able to stay calm and realize what will happen at the end," said Jones.