Mine isn't vented; I don't recall the instructions mentioning it.


As well with my instructions. NO mention of venting. A Google check with
a propane refrigerator manufacturer's FAQs says "if it is functioning
properly", it needs no venting.

I know that carbon monoxide is bad stuff, so, just wanted to ask people
about their experiences.

Don't know a thing about propane refrigerators. However, if you feel
uncomfortable about it not being vented. I'd vent it. The value of peace of
mind might exceed the cost of your worry.
A good friend of mine from college lost a cousin due to a gas leak. He
slept through the ordeal. I think it was propane he was using somewhere in
his house. Sorry, don't remember the specifics.