Ozone was a gas with a distinctive and unpleasant odor that was used in air conditioning. It could be created by an excess energy in the air, often caused by the firing of a blaster or the explosion of a pulse bomb. The recirculated air of the Death Star stank of ozone, as did the noxious Mustafarian marsh, Corvax Fen. The Force vision "Dark Rey" wielded a crimson hinged double-bladed lightsaber that reeked of ozone.