I've got several oil lamps. I like them for summer time power outages as they don't produce much heat.

I use both liquid fuel and propane lanterns in the house all the time. If your not airtight, there is no danger. But I would say that after you turn them off to put them outside...they can produce some noxious fumes after you turn them off. While they are burning, they are fine. Just crack a window.