People underestimate how quickly Carbon Monoxide can overtake you and how little air there actually is indoors. I was helping someone with their car once time. It was winter and we were starting it to see if something was working. He kept starting it with the garage door closed and seemed annoyed when I would open the door to vent the exhaust. I’d rather be slightly cold than dead. Those people that use keorose or diesel heaters on their garages in the winter just sketches me out. I’m ready to ditch natural gas from my home altogether because I just don’t like the idea of it.