[comanchefirebird]

I heat my shop with a 40 foot radiant heat tube that burns propane.
The sidewall exhaust vent has (had) a wire mesh screen tack welded up inside the exit. Apparently it had rusted out ...
I noticed a piece of dead grass hanging out of the exit pipe this week. Starlings had completely plugged up at least two feet of the exit vent with twigs and dead grass to build a nest. It was apparent that I had turned it on at least once in the last couple of week as some of the material was charred black. It was likely the same day I had a nagging headache ...

I had been thinking about getting a carbon monoxide (CO) detector for the shop. Next time to town I will be getting one.

Screwed on a piece of mesh that is very visible from the ground -pic attached

So if you heat with a radiant heat tube, please check your exit vent. Make sure it is screened to keep critters out