In article .com,
"Pete C." wrote:

[snip]

Liguid CO2 isn't cryogenic like Liquid nitrogen, so a CO2 cooled chamber
will be a good deal less dangerous than an LN2 one.

Like most any inert gas, CO2 will displace air and can be an issue if
enough is released in a confined space. Since it will sit low it tends
to be a greater risk to children and animals, which probably aren't an
issue in a work environment.

As far as I know, there is no CO2 mixed into medical O2. I have a couple
med O2 cylinders here, and an oxygen analyzer and I read 100% O2.

There is one exception - treating cases of carbon monoxide poisoning. If
I recall, the mix is 5% CO2 and 95% O2. The CO2 displaces the CO, and
the almost pure oxygen keeps you alive while this happens. Reportedly
it is very stressful to breathe this stuff - you feel that you cannot
get enough air, and yet are perfectly OK.

Joe Gwinn