Ok, so we have a gas fireplace. It's chilly tonight, so we turned it on for a while. There was a bit of smell of oil, but nothing rotten-egg like so I didn't think it was a problem.
After about an hour, I had a headache, was falling asleep, and was so braindead I couldn't put two words together. This in itself is not terribly unusual for me, but the suddenness and strength of it was. I pulled myself together enough to turn off the fireplace, and after about 15 minutes I pretty much fine again.
It didn't seem to affect Andrei at all, which is odd.
A quick Goggle consultation told me that apparently new gas fireplaces (as ours is; it had never been on for more than a few seconds at a time before tonight) will smell 'weird' for about the first 10 hours of use.
Smelling weird is one thing; causing a dangerous degree of brain malfunction is something else. And I don't like it.
Edit: mostly fine. Still dropping words and making odd typos. But getting better as time goes on. Leaving errors for future reference just in case.