Michael Volkin is the author of The Ultimate Basic Training Guidebook available at www.UltimateBasicTraining.com

The gas chamber may be the most anxiety filled and emotionally challenging exercise recruits must overcome at basic training. Even the name, Gas Chamber, sounds ominous. The exercise requires each recruit to be exposed to tear gas. Yes, each and every Army, Navy, Marine and Air Force recruit must go into the chamber and experience the stinging, heavy coughing, and gagging caused by this gas - that's the bad news.

What's the good news? As soon as you walk outside, the exercise is over. The CS gas leaves your system quickly and any pain you are feeling dissipates within seconds. In fact, the most painful aspect of this exercise is the anticipation of the exercise itself.

Why the Gas Chamber?
I am often asked why this exercise is even necessary. Some would say that Drill Sergeants are jerks and like to torture recruits, others would say the gas chamber is necessary because you need to train your body to get used to the CS gas. Neither of those explanations are true. The real reason all recruits must go through the gas chamber is they need to learn to be confident in their chemical gear. If you’re not confident your chemical gear will work, you won't be confident in combat if chemical or biological warfare should occur.

Inside the Gas Chamber
The gas chamber is a room that has a controlled concentration of CS (orto-chlorobenzylidene-malononitrile) gas, more commonly known as tear gas. Tear gas is the active ingredient in Mace™ and used for self defense and riot control by the police. Tear gas is an irritant; specifically, it irritates mucous membranes in the eyes, nose, mouth and lungs, causing tearing, sneezing, coughing, etc.

What to Expect
You will walk in a gas filled room with a dozen other recruits with your face mask on. You will notice instantly that your chemical gear works. Then you will have to take off your mask and sing a song, count, call out your service number or something similar and breathe the gas. The best advice I can give you at this point is to not hold your breath. If a drill sergeant sees you holding your breath or lip-syncing, you will have to do the entire exercise again. Not to mention the other recruits that are in the room with you will be waiting for you to finish. I am sure they want to get out of the gas chamber as much as you do. 

After the exercise the gas will dissipate and the whole incident will be a memory.  You can read a more in-depth description about the gas chamber in my book at available at www.UltimateBasicTraining.com.