scuba tanks have oxygen and a bit of helium inside....
actually, not really .... most times it's just normal compressed
air ....
sometimes augmented with a bit of oxygen, and we call it nitrox
....
anything with helium (trimix) is mostly beyond the realm of
recreational divers .....
but a ruptured tank is still a scary sight .... imagine one
rupturing in close proximity to you .... >.<
