This event is an experience no Marine or Officer forgets. Recruits will be transported to the gas chamber classroom where they will each be issued an M50 Joint Service General Purpose Mask (JSGPM) and two filters before being seated in the classroom. They will then receive training on the dangers presented by Chemical, Biological, Radiological, and Nuclear (CBRN) threats which they may face in the operating forces. They will then be taught the purpose, wear, and maintenance of the M50 JSGPM. Recruits will conduct a test fit of their masks prior to departing the classroom.
The culmination of this training event is the chamber itself. Recruits will depart the classroom and be laced in sticks (or lines) of 25 to 50 individuals. They will enter the Gas Chamber where they will be exposed to chlorobenzalmalononitrile, or CS gas, also known as tear gas. While exposed to this gas, recruits will be required to exhibit proficiency in clearing the gas from their masks. If they fail to do so, they will experience irritation in the eyes and discomfort while breathing. For those facing difficulties, the discomfort will taper off after they depart the chamber.
After recruits complete training in the chamber they will move around to help dissipate the gas crystals from their uniforms. They will then clean their faces and masks in preparation of the next event. This training normally occurs the same day as the Rappel Tower event.