@MichaelsMind

A depleted oxygen atmosphere is much nastier.

I believe high CO2 concentrations are much more noticeable that just depleted oxygen levels. The urge to breathe is caused by high CO2 in the blood, not by low O2 levels. This is why areas with low oxygen but normal CO2 levels are so dangerous, you lose judgement and pass out without realizing anything is wrong.

CO, of course is a dangerous poison.

@cptbutton @MichaelsMind High CO2 environments can be super dangerous. We had a rule in a university dining hall I worked at that you were not allowed to take the compost bins to the compost bin room alone because the door swinging shut behind you could result in a high CO2 displacing O2 environment real fast.