I don't even trust scentsy, ( natural wax, scented and heated with a low wattage light bulb underneath, so it's wick less) the company claim they are animal friendly, but I can only see dogs and cat mentioned, I do use it in summer with all windows open in a different room though. Pigs have never shown signs of bad breathing or anything, but now I have pet rats, I have to be even more cautious.