[propbeanie]

The German U-Boats had a CO2 "eater", or absorbent canister (paint can sized??), but the material was apparently rather difficult and expensive to make, since there were only like four on a boat, and "For Emergency Use Only" kind of thang (one of the movies shows that - ??). The US had the Momsen lung, which was a "re-breather", and functioned in a similar manner, but was for use in the water. Seems to me the US had something close to ready for release by the time the end of the war came - but I am not certain of that. The problem is that you can "absorb" the CO2, but that does not replace the oxygen content of the atmosphere, unless you use the pressurized air... which was known to cause ear and nose bleeds...