Steg's story is a little more perilous, and a perfect reminder of why every single home must have at least one carbon monoxide detector!
When the fire department arrived with their portable detector tools, they said that the level of CO (which cannot be seen or smelled) in the apartment had already reached such a level that we would have been dead in 8 hours or less. We would have just gone to sleep and never woken up for shul in the morning.This is not a risk anyone should ever take. Buy a CO detector TODAY. (They're about $20.) We bought one on Sunday.