US state Alabama seeks to be first to execute a prisoner by making him breathe pure nitrogen

A US state is seeking to become the first to execute a prisoner by making him breathe pure nitrogen.

The Alabama attorney general’s office has asked the state Supreme Court to set an execution date for death row inmate Kenneth Eugene Smith.

The court filing has indicated that Alabama plans to put him to death by nitrogen hypoxia, an execution method that is authorised in two other states - Oklahoma and Mississippi - but has never been used.

Nitrogen hypoxia is caused by forcing the inmate to breathe only nitrogen, depriving them of oxygen.

Nitrogen makes up 78% of the air inhaled by humans and is harmless when inhaled with oxygen.

While proponents of the new method have theorised it would be painless, opponents have likened it to human experimentation.

The state authorised nitrogen hypoxia in 2018 amid a shortage of drugs used to carry out lethal injections, but the state has not attempted to use it until now to carry out a death sentence.

Alabama attempted to execute Smith by lethal injection last year, but called off the execution because of problems inserting an IV into his veins.

The disclosure that Alabama is ready to use nitrogen hypoxia is expected to set off a new round of legal battles over the constitutionality of the method.

The Equal Justice Initiative, a legal advocacy group that has worked on death penalty issues, said Alabama has a history of “failed and flawed executions and execution attempts” and “experimenting with a never before used method is a terrible idea.”

“No state in the country has executed a person using nitrogen hypoxia and Alabama is in no position to experiment with a completely unproven and unused method for executing someone,” Angie Setzer, a senior attorney with the Equal Justice Initiative said.

Smith, now 58, was one of two men convicted in the 1988 murder-for-hire killing of a preacher’s wife.

The Alabama attorney general argued it is time to carry out the death sentence.

“It is a travesty that Kenneth Smith has been able to avoid his death sentence for nearly 35 years after being convicted of the heinous murder-for-hire slaying of an innocent woman, Elizabeth Sennett,” Attorney General Steve Marshall said in a statement on Friday.

Want a quick, expert briefing on the biggest stories of the day? Listen to What You Need To Know...