Originally Posted by
FyreFighter
They could be, but the writing on the canister indicates these are GP-5 canisters made in 91. Production of the masks ended in 1990, so these are likely replacements for masks still kicking around. It is almost certain to contain asbestos, which is not going to be a problem unless the canister has been battered around at some point in its 30 year life.
I can't say anything about the mask, but I would steer well clear of those canisters unless they are certified asbestos-free and are for novelty purposes only. The thread would be similar diameter but different pitch. Some reports clean they screw on to NATO masks but does it make sense to take a risk with a device meant to save your life?