Safety precautions Thermacell is approved by EPA, but you need to use it away from uncovered food while operating it. It's also important to avoid directly inhaling its vapor because of the allethrin that it contains. Allethrin is toxic to bees, cats, and fish, therefore, avoid exposing it to these creatures.Oct 5, 2019
Is Thermacell safe inside?
Only for outdoor use as an insect repellent. Do not use indoors, in tents or in any enclosed area. Do not insert anything other than ThermaCELL® mats into the appliance.Jan 9, 2015