Richard Glossip: Man convicted of murder set to become first prisoner on death row executed by nitrogen gas

Supreme court heard the injection is like being 'burned alive'

A prisoner on death row in Oklahoma is set to become the first American to be executed by deadly nitrogen gas.

The use of the injection is currently being contested in the Supreme Court, as judges appear split over whether it is a breach of the Constitution’s ban on cruel and unusual punishment.

Richard Glossip and fellow convicted murderers John Grant and Benjamin Cole contend that the proposed sedative midazolam is unsuitable for their executions, as it cannot achieve the level of unconsciousness required for the procedure.

Justice Elena Kagan said if midazolam does not work, condemned inmates would essentially be "burned alive" by one of the other drugs used in the process, potassium chloride.

The three-drug process used by Oklahoma prison officials has been under scrutiny since a controversial execution a year ago of convicted murderer Clayton Lockett.

Lockett could be seen twisting on the gurney after staff failed to place the intravenous line properly.

Chief Justice John Roberts and Justice Antonin Scalia questioned whether Lockett's case was relevant because there was evidence the drug was not properly administered.

"I mean, if in fact the execution was not properly conducted, I don't see how you can blame it on the drug," Scalia said.

Glossip was sentenced to death for hiring a colleague to kill Barry Van Treese who owned the motel where the pair worked.

He was due to be executed earlier this year, but earned a reprieve.

Additional reporting by Reuters