Alabama will attempt the nation’s first execution using nitrogen gas
MONTGOMERY, Ala. — Alabama is preparing to use a new method of execution: nitrogen gas.
Kenneth Eugene Smith, who survived the state’s previous attempt to put him to death by lethal injection in 2022, is scheduled to be put to death Thursday by nitrogen hypoxia. If carried out, it would the first new method of execution since lethal injection was introduced in 1982.
The state maintains that nitrogen gas will cause unconsciousness quickly but critics have likened the never-used method of execution to human experimentation.
What is nitrogen hypoxia?
Nitrogen hypoxia execution would cause death by forcing the inmate to breathe pure nitrogen, depriving him or her of the oxygen needed to maintain bodily functions.
Has it ever been used?
No state has used nitrogen hypoxia to carry out a death sentence. In 2018, Alabama became the third state — along with Oklahoma and Mississippi — to authorize the use of nitrogen gas to execute prisoners.
Some states are looking for new ways to execute inmates because the drugs used in lethal injections, the most common execution method in the United States, are increasingly difficult to find.
How is it supposed to work?
Nitrogen, a colorless, odorless gas, makes up 78% of the air inhaled by humans and is harmless when breathed with proper levels of oxygen.
The theory behind nitrogen hypoxia is that changing the composition of the air to 100% nitrogen will cause Smith to lose consciousness and then die from lack of oxygen.
Much of what is recorded in medical journals about death from nitrogen exposure comes from industrial accidents — where nitrogen leaks or mix-ups have killed workers — and suicide attempts.
What does the state plan to do?
After Smith is strapped to the gurney in the execution chamber, the state said in a court filing that it will place a “NIOSH-approved Type-C full facepiece supplied air respirator” — a type of mask typically used in industrial settings to deliver life-preserving oxygen — over Smith’s face.
The warden will then read the death warrant and ask Smith if he has any last words before activating “the nitrogen hypoxia system” from another room. The nitrogen gas will be administered for at least 15 minutes or “five minutes following a flatline indication on the EKG, whichever is longer,” according to the state protocol.
The state heavily redacted sections of the protocol related to the storage and testing of the gas system.
The Alabama attorney general’s office told a federal judge that the nitrogen gas will “cause unconsciousness within seconds, and cause death within minutes.”