"Roger" wrote in message
...
No, CO2 does not poison you. Like the pillow over a head/face it can
cut off the air, but it is not a poison. It only mechanically
prevents you from breathing air with O2 in it.

Actually, it does more than that. The CO2 level in your blood affects your
breathing reflex, and while some elevation is what helps you know to take
another breath, too much can interfere with your breathing in other ways.

If anything, CO is more of a "mechanical blockage", because "all" it does is
bind to the blood cells, preventing them from carrying O2. CO2 actually
messes with your body's natural breathing control.

I wouldn't really call either a "poison", but it seems to me that the words
has been used pretty loosely by everyone involved in this thread.
Nit-picking about whether either CO or CO2 seems fruitless.

Pete