Your ignorance is showing. I spent 22 years in the AF and each time I was in an overseas unit or subject to deployment to an overseas area I had to go to the Chamber every six months. I also had to go to the chamber in basic training and each time they changed the chemical equipment for a refresher.
I also had to spend a six hour period in the full ensemble every four months while performing my regular duties. This included times when the outside temperature was over 100 degrees.