Unlike a simple fan, Aridus Den can cool below room temperature. But it differs itself from an air conditioner or refrigerator yet again in that it does not use any refrigerant.
Any of those gases - methyl chloride, CFC, HCFC, HFC - are not only toxic to animals and humans to inhale, but is also one of the main source of air pollution when escaped (yes, they do escape over time).
As for you, You'd never need to call a mechanic because of a gas leak. For the animals, they will be intrinsically safe.