Woody wrote:

If anyone in charge of people's lives is watching... please check these
websites...

for buying time when the air is thin, or blackdamp situations:
http://www.submersiblesystems.com/


I hold a Master Scuba Diver rating and will tell you these things are
not thought of very well in the experienced scuba diving community.
They hold about 3 cft of air. That MIGHT give them 5 minutes of air at
best. Highly unlikely they would have made any difference in this mine
disaster. They were originally designed for military helicopter pilots
that crashed at sea, to give them time to get out of the aircraft and to
the surface.