Newshound wrote:
Not quite the only issue. Even a CO2 tank in a fire is a bomb,...

I don't think so - they have pressure relief valves. Plugs, actually, IIRC.

And if you happen to have confined spaces,
particularly a cellar or similar, there is a real asphyxiation risk from a
leak. ...

I don't think so - breathing just a little would be so distressing that
you'd immediately get-the-hell-out. It's the rise in CO2 concentration
in our lungs that makes it so hard to hold your breath for very long.
There's still plenty of oxygen in your lungs but the rising CO2 says:
BREATH! BREATH!! You start experiencing that in your cellar and you'll
be out of there long before asphyxiation is a risk.

Bob