How did these people die? I saw this in my local news blog this a.m., it caught my

[The Velveteen Ocelot]

3. Nitrogen is not the same as nitrous oxide.

Breathing pure nitrogen will kill you because there's no oxygen. 78 percent of the air is nitrogen gas, so people assume that nitrogen is not harmful. However, nitrogen is safe to breathe only when mixed with the appropriate amount of oxygen. A nitrogen-enriched environment depletes oxygen, and can be detected only with special instruments. If the concentration of nitrogen is too high (and oxygen too low), the body becomes oxygen deprived and asphyxiation occurs. Nitrous oxide ('laughing gas') is a compound of nitrogen and oxygen used as an anesthetic and it is administered in a mixture with oxygen, so for short periods of time it isn't dangerous like pure nitrogen.