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Inert gas asphyxiation

Updated: 12/10/2025, 5:54:28 PM Wikipedia source

Inert gas asphyxiation is a form of asphyxiation which 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. 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 the oxygen concentration in inspired gas and blood to dangerously low levels, thereby eventually depriving 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 US, at least 80 people died from accidental nitrogen asphyxiation between 1992 and 2002. Hazards with inert gases and the risks of asphyxiation are well-established. An occasional cause of accidental death in humans, inert gas asphyxia has been used as a suicide method. Inert gas asphyxia 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 approved in some places as a method of capital punishment. In the world's first instance of its use, on January 25, 2024, Alabama executed convicted murderer Kenneth Eugene Smith via this method. It has since been used seven more times, six times in Alabama and once in Louisiana, which first used it on March 18, 2025. Alternatively, the term hypoxia has been used but this usage is flawed given that hypoxia does not necessarily imply death. On the other hand, asphyxiation is technically incorrect given respiration continues and the carbon dioxide metabolically produced from the oxygen inhaled prior to inert gas asphyxiation can be exhaled without restriction, which can prevent acidosis and the strong urge to breathe caused by hypercapnia.

Tables

· Capital punishment › List of people executed by nitrogen hypoxia
Kenneth Eugene Smith
Kenneth Eugene Smith
No.
1
Name
Kenneth Eugene Smith
Race
White
Age
58
Sex
M
Date of execution
January 25, 2024
State
Alabama
Method
Nitrogen Hypoxia
Alan Eugene Miller
Alan Eugene Miller
No.
2
Name
Alan Eugene Miller
Race
59
Age
September 26, 2024
Carey Dale Grayson
Carey Dale Grayson
No.
3
Name
Carey Dale Grayson
Race
50
Age
November 21, 2024
Demetrius Terrence Frazier
Demetrius Terrence Frazier
No.
4
Name
Demetrius Terrence Frazier
Race
Black
Age
52
Sex
February 6, 2025
Jessie Hoffman Jr.
Jessie Hoffman Jr.
No.
5
Name
Jessie Hoffman Jr.
Race
46
Age
March 18, 2025
Sex
Louisiana
Gregory Hunt
Gregory Hunt
No.
6
Name
Gregory Hunt
Race
White
Age
65
Sex
June 10, 2025
Date of execution
Alabama
Geoffrey Todd West
Geoffrey Todd West
No.
7
Name
Geoffrey Todd West
Race
50
Age
September 25, 2025
Anthony Todd Boyd
Anthony Todd Boyd
No.
8
Name
Anthony Todd Boyd
Race
Black
Age
54
Sex
October 23, 2025
No.
Name
Race
Age
Sex
Date of execution
State
Method
Ref.
1
Kenneth Eugene Smith
White
58
M
January 25, 2024
Alabama
Nitrogen Hypoxia
2
Alan Eugene Miller
59
September 26, 2024
3
Carey Dale Grayson
50
November 21, 2024
4
Demetrius Terrence Frazier
Black
52
February 6, 2025
5
Jessie Hoffman Jr.
46
March 18, 2025
Louisiana
6
Gregory Hunt
White
65
June 10, 2025
Alabama
7
Geoffrey Todd West
50
September 25, 2025
8
Anthony Todd Boyd
Black
54
October 23, 2025

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