Oklahoma officials announced a plan to use nitrogen gas to execute inmates once the state resumes using the death penalty, marking the first time a USA state would use the gas to carry out capital punishment.
State officials made the announcement Wednesday, saying they cannot get the drugs needed for lethal injections because some drugmakers oppose having their products used in executions.
In 2015, Oklahoma passed a law allowing nitrogen to be used in executions if the lethal injection was ever ruled unconstitutional, or if the drugs became unavailable.
Dale Baich, a federal public defender and one of the attorneys representing Oklahoma death row prisoners in a federal lawsuit challenging the state's lethal injection protocol said: "How can we trust Oklahoma to get this right when the state's recent history reveals a culture of carelessness and mistakes in executions?"
The use of nitrogen gas has already been approved by the state legislature, but it was only a reserve method and has never been attempted anywhere in America. In 2016, the state's grand jury recommended such a step be taken, as Oklahoma has had difficulty obtaining lethal injection drugs.
Oklahoma is among 31 USA states that permit the death penalty and it has carried out 112 executions, the third highest number for a U.S. state, since 1976 when capital punishment was reinstated, according to the Death Penalty Information Center, a non-profit capital punishment monitor.
"It is the - a common procedure in states and in countries that allow for assisted suicide", Hunter said.
In 2014, Oklahoma drew intense scrutiny for its death-penalty procedures after the execution of Clayton Lockett gained worldwide attention. Oklahoma, which carried out at least one execution every year between 1995 and 2015 - one of only two states to do so, along with Texas - has not executed an inmate since then. He said state leaders had to "to utilize an effective and humane manner that satisfies both the Constitution and the court system". He said he'd heard the state was going to stick with lethal injection in part because the new method is untested and going to require a lot of appeals.
Mr Hunter said: "Well documented research has shown that individuals who are exposed to excessive amounts of inert gas experience fatigue dizziness, perhaps a headache, loss of breath and eventual loss of consciousness". A bill that would make the electric chair the state's default execution method is now before the House Committee on the Judiciary. It was not likely until the end of the year at the earliest, The Oklahoman newspaper reported.
The DOC is working to develop a protocol and procedures for future executions.