Originally Posted By: MostlyHarmless
Originally Posted By: hikermor
I am a bit hazy on the details - I wasn't there. But it did involve incomplete combustion (that was the malfunction) of a pilot light. No explosive atmosphere was involved. Individual who woke up did so with a serious headache.


Just want to emphasize this point: CO and CO2 are very different animals. CO2 is totally harmless. CO is highly poisonos. A good combustion gives you loads of CO2 and very little CO. Incomplete combustion will give you a lot more CO.

Now the wicked part of this is: If you "burn up" too much of the oxygen, the combustion will take revenge by spewing out lots of CO. Both lack of oxygen and abundance of CO is deadly. There doesn't have to be anything wrong with the pilot flame at all, just insufficient ventilation...


Essentially correct. It's the CO that's the major hazard to guard against in situations like this.

But note that CO2, in high concentrations and confined spaces, is also a hazard. This is more of a concern in industrial facilities. That means CO2 is, uh, "mostly" harmless. whistle