They run people through the gas chamber twice a year now?
At least hey used to before I retired in1992.
I didn't see the gas chamber even in Basic. The winter of 76-77 up at Great Lakes was so cold Gas Mask class wasn't held. I never saw it on the ship. We were sent several times {about a half dozen or more times in my case} to Fire Fighting Classes just outside the base in Norfolk.
They had us put out a fire and get out without an OBA for oxygen. Any Damage Control qualified sailor should be able to do as much. You wrapped your lips around the working fire hose for oxygen. It was a back up that worked especially if you were in a fire and the OBA failed which the older models of the 1970's were notorious for doing.