Breathing helium with insufficient oxygen leads to suffocation. Without carbon dioxide, your body doesn't get the signal that something is wrong. If you breath straight helium, don't hold your breath, and don't do it for too long. Seriously.
Sun 27 Sep, 2009 07:12 pm
Not sure about that, Nick. A helium/oxygen mixture is used instead of the normal oxygen/nitrogen mix to avoid becoming bent.
Sun 27 Sep, 2009 11:58 pm
Helium does not "bind" to anything*. Neutral helium at standard conditions is non-toxic, plays no biological role and is found in trace amounts in human blood. The danger, that of asphyxiation, arises simply because it displaces oxygen needed for normal respiration. Also, if helium is inhaled directly from pressurized cylinders the high flow rate can fatally rupture lung tissue (barotrauma).