Officials announced Wednesday it will replace lethal injection as Oklahoma's primary way to carry out capital punishment.
Maya Foa from Reprieve, who has led the campaign to restrict the use of lethal injection drugs, welcomed the announcement that Oklahoma will no longer attempt to acquire them, but told Sky News that nitrogen was an untested method, particularly when a prisoner was resisting. "Using an IGI will be effective, simple to administer, easy to obtain, and requires no complex medical procedures".
Oklahoma has had one of the busiest death chambers in the US, but hasn't carried out an execution since 2015 after a series of mishaps, including a botched lethal injection in 2014 that left an inmate writhing on the gurney and drug mix-ups in which the wrong lethal drugs were delivered to the prison for executions.
On Tuesday night, Conaway appeared to backtrack from his earlier remarks, telling reporters that whether Russian meddling hurt Hillary Clinton or helped Trump was a "glass half-full, glass half-empty" question.
The execution table in the death-penalty chamber at the Oklahoma State Penitentiary in McAlester. Still, at a time when states have struggled to obtain lethal injection drugs, Oklahoma's move is the latest in a series of dramatic efforts some officials have made to continue carrying out death sentences.
Oklahoma officials said they didn't know when executions would resume but hope to draft the new gas protocols within the next 120 days.
No state or country has ever used nitrogen for executions.
While use of the death penalty has dramatically declined nationwide, a handful of states have been outliers and continued to carry out executions. 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.
Seventeen inmates are eligible for execution and have exhausted the appeal process. "How can we trust Oklahoma to get this right when the state's recent history reveals a culture of carelessness and mistakes in executions?"
Nitrogen's introduction as a potential execution method in Oklahoma isn't a surprise.
In assisted suicides, nitrogen hypoxia ends life by reducing the oxygen that is breathed in, sometimes with a hood or other device placed over the head.
Unknowns remain, give that state officials only recently began developing the protocols.
Robert Dunham, the executive director of the Death Penalty Information Center, expressed doubts about the method in 2015, when the law was being changed to allow for nitrogen executions. Alabama legislators are considering a bill on the issue this year.