Hi,
we did simulated gas bottle fires with the fire service as part of volunteer training.
They are designed to vent the gas for safety when over heated.
The free gas is of course a potential hazard as it can go "whoomph" in spectacular fashion if a large volume is involved.
The bottles them selves should not explode if they vent down correctly.
If the vented gas is burning, then the potential for 'whoomph" is eliminated, and although spectacular and noisy, the huge flame from the vent is a much safer option than having free gas on the ground.
For that reason, if a bottle is burning at the vent, (which should always be pointed away from the wall) never knock the flame out.
The correct procedure is to cool the bottle with water from a hose till the venting stops, disconnect the bottle and get it out of the hot area.
Not always possible I know, and the idea of having a quick detach arrangement for gas bottles seems like an idea worth further thought.
cheers