Perfluorobutane (PFB) is an inert, high-density colorless gas. It is a simple fluorocarbon with a n-butane skeleton and all the hydrogen atoms replaced with fluorine atoms.
Due to its inert nature and high density, inhaling perfluorobutane makes one's voice deeper. Caution is advised as heavier gases are difficult to breathe out and may cause inert gas asphyxiation.
Environmental impacts
If perfluorobutane is released to the environment, it will not be broken down in air. It is not expected to be broken down by sunlight. It will move into air from soil and water surfaces. If it is exposed to conditions of extreme heat from misuse, equipment failure, etc., toxic decomposition products including hydrogen fluoride can be produced.[6]