("kd5sak" wrote)
I think nitrogen and carbon dioxide are both heavier than air ( that is,
they will pool in low areas) A sufficient excess of either can suffocate
you. You can wind up drowning without getting wet. As a matter of fact, I
saw a cable channel episode recently describing the loss of a few buffalo
in a small valley in Yellowstone Park from such an emission near one of
the active geyser areas. That incident probably involved a mix of volcanic
gases rather than just CO2 but no one knows for sure, since it was a
transient unmonitored event.


PBS - Savage Planet: Degassing Lake Nyos

http://www.pbs.org/wnet/savageplanet.../indexmid.html

"Some 1,700 people living in the valley below Lake Nyos in northwestern
Cameroon mysteriously died on the evening of August 26, 1986. Word of the
disaster spread, and scientists arrived from around the world. What they
discovered was that the crater lake, perched inside a dormant volcano, had
become laden with carbon dioxide gas. This gas had suddenly bubbled out of
the lake and asphyxiated nearly every living being in the surrounding valley
community."


Montblack