 Inert gas hasphyxiation. Inert gas hasphyxiation is a form of asphyxiation which results from breathing a physiologically inert gas in the absence of oxygen, or a low amount of oxygen, rather than atmospheric air which is largely composed of nitrogen and oxygen. Examples of physiologically inert gases, which have caused accidental or deliberate death by this mechanism, are argon, helium, nitrogen and methane. The term physiologically inert is used to indicate a gas which has no toxic or anesthetic properties and does not act upon the heart or hemoglobin. Instead, the gas acts as a simple diluent to reduce oxygen concentration in inspired gas and blood to dangerously low levels, thereby eventually depriving all cells in the body of oxygen. According to the U.S. Chemical Safety and Hazard Investigation Board, in humans, breathing an oxygen-deficient atmosphere can have serious and immediate effects, including unconsciousness after only one or two breaths. The exposed person has no warning and cannot sense that the oxygen level is too low. In the U.S., at least 80 people died due to accidental nitrogen asphyxiation between 1992 and 2002. Inherit gases and the risks of asphyxiation are well established. An occasional cause of accidental death in humans, inert gas hasphyxial with gases including helium, nitrogen, methane and argon has been used as a suicide method. Inherit gas hasphyxial has been advocated by proponents of euthanasia, using a gas-retaining plastic hood device colloquially referred to as a suicide bag. Nitrogen asphyxiation has been suggested by a number of lawmakers and other advocates as a more humane way to carry out capital punishment. In April 2015, the Oklahoma Governor Mary Fallon signed a bill authorizing nitrogen asphyxiation as an alternative execution method in cases where the state's preferred method of lethal injection was not available as an option. In March 2018, Oklahoma Attorney General Mike Hunter and Corrections Director Jo Amal Baugh announced a switch to nitrogen gas as the primary method of execution.