Are indoor propane heaters safe?

Propane heaters identified as "indoor safe" feature an oxygen depletion sensor that automatically shuts down the heater if the air flow is below safe levels. Heaters labeled for “outdoor use only” burn fuel at a high rate and are not safe indoors or in campers, garages and other enclosures.

Although some propane heaters are made specifically for temporary indoor use, the operator must read the operating instructions and packaging and only use heaters labeled as "indoor safe." Outdoor-only propane heaters are usually propane-tank mounted radiant heaters, or portable forced-air heaters, and are not to be used indoors, as their risk of carbon monoxide poisoning is high.