A man waiting on death row to be killed has opted to be executed by nitrogen hypoxia as he has a fear of needles.
The never-before-tried method was approved in the state of Alabama, USA in 2018, but has yet to be tried on a real prisoner.
Alan Eugene Miller was convicted of killing three men in a workplace shooting in 1999 and was sentenced to death.
His execution date was set for Thursday, September 22 and James Houts, a deputy state attorney general, told District Judge R Austin Huffaker Jr that it is "very likely" the method will be available.
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Miller is currently due to be killed by lethal injection on that date and the final decision on whether to use the new method is up to Corrections Commissioner John Hamm.
What is nitrogen hypoxia?
Hypoxia is when there is not a sufficient amount of oxygen in the tissues for the body to perform its regular functions.
Nitrogen hypoxia is a form of inert gas asphyxiation.
Nitrogen is safe to breathe – it makes up 78 per cent of what we inhale – but only when mixed with suitable amounts of oxygen.
Inert gas asphyxiation uses gasses that are not typically poisonous, such as nitrogen, methane or helium, as a diluting agent for atmospheric gasses.
The oxygen concentration is reduced to fatally low amounts, according to the US Chemical Safety and Hazard Investigation Board.
Once oxygen levels fall below 16 per cent, breathing becomes difficult.
At four per cent to six per cent, a person can enter a coma in as little as 40 seconds.
Two other states in the US - Oklahoma and Mississippi - have also approved the use of nitrogen hypoxia.
Russell Bucklew, a man incarcerated in Missouri tried to get approved for nitrogen hypoxia, but was denied in a lawsuit that went to the US Supreme Court.
Bucklew was initially scheduled for execution in 2014, but sued the director of the Missouri Department of Corrections asking for the use of nitrogen hypoxia instead of lethal injection due to a medical condition he had.
In the opinion of the Court, Justice Neil Gorsuch denied the request, saying that nitrogen hypoxia had been untested and Missouri could not properly prepare it.
Bucklew's proposal should have included how the nitrogen gas should be administered, in what amounts, how long it would take to work and how to keep the execution team safe, he said.
The Court also ruled there was no evidence to support Bucklew's claim that hypoxia would be less painful.
He was executed in 2019 by lethal injection.
