- Apr 29, 2019
I myself don't have any other more authoritative source for the claim about the mask losing its seal around the face as unconsciousness sets in. Here on SS is the only place I've seen that assertion made before and as I noted I was simply repeating it.I can kind of see that for the type of mask pictured with the debreather, it doesn't look like it's attached very securely to your head at all. But I can't see that for a proper scuba mask for example.
Also, is there actually a source for this claim other than it being repeated here in the forum over and over? It's really frustrating that people keep reposting it without specifying what kind of setup is being talked about and what the source of the claim is. It's kinda like with the "fact" that you can't get pure helium anymore, when that only applies to a subset of the helium sold specifically for inflating balloons, which nobody here recommends you buy anyway because you can't even fit a flow regulator to those tanks.
ADDITIONAL EDIT: This technical article discusses the issue of the debreather mask losing its seal as the people wearing it lost consciousness: