Yeah, nothing better than spreading a fart out with a fan.
Eggzactly Super, we cook with propane without giving it a thought. We even use the ceramic catlytic heaters inside all night long without worrying about co2. Maybe that wouldn't work out so well after it's all sealed up, but in the early stages of a build this thing leaks heat pretty bad. I never had any issues with co2, because you can feel it if you're conscious. Apparently I didn't die so...