vbcapt said:We used re-breathers when I was in the Navy. They're using SCBA's now which was a very smart move. Our re-breathers were called OBA's (oxygen breathing apparatus). Ours were worn on the front of your body and you had to install & activate a canister that contained postassium super-oxide & the canister got very hot once activated. It lasted 60 minutes max, less with exertion. The downside to these canisters were if they came into contact with pertoleum...ka-boom.