Inert gas asphyxiation
Inert gas asphyxiation is a form of asphyxiation that results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen (hypoxia), rather than atmospheric air (which is composed largely of nitrogen and oxygen). Examples of physiologically inert gases, which have caused accidental or deliberate death by this mechanism, are argon, xenon, helium and nitrogen.