Carbon dioxide - by what mechanism is it poisonous?

[William Tivol]

JIM NAPIER (NAPIERJ at Agresearch.cri.nz) wrote:
: I am interested in finding out the mechanism by which CO2 is poisonous. 

: I used to think that CO2 is not poisonous, and that it only kills when it 
: displaces the oxygen in a container.  I have since been told that this is 
: NOT the case and that it IS toxic.

Dear Jim,
	When the CO2 concentration in the air gets above a certain value--
I think it is ~5-10%--it acts to paralyze the diaphragm.  I don't know
the mechanism on a more detailed level.
				Yours,
				Bill Tivol