Carbon Monoxide!?
Weird. The smoke alarm went off, not incredibly odd when I am using the fireplace, but it wasn't the smoke detector. It was the CO alarm. I was totally surprised. It had never gone off as long as I have had one, over many many years. Yep, after resetting it a few times. It was getting a reading over 200 ppm CO. When I took it downstairs I got a reading near 300 ppm. I started getting light headed at this point. After thinking maybe the furnace heat exchanger failed and puzzling around a bit I figured out what happened. As part of the huge winter storm that recently covered almost half of the US, we lost our electricity. So, being well prepared, I rolled out the generator and started doing what I normally do. The generator (although it was completely outside) was creating CO to get in the house. Using the fireplace draft (and possibly other leaks) the whole house created a vacuum around the seal of the basement garage door. After the CO got into the house the forced air heat...