By Finn Bunting

Oklahoma has authorised the use of nitrogen gas to execute death row inmates despite facing controversy following the botched execution of Clayton Lockett one year ago.

All pending executions have been put on hold in Oklahoma while the Supreme Court reviews the use of lethal injections in response to the national and international outcry after the Lockett execution. Condemnation came from as high as President Obama and the United Nations.

Governor Mary Fallin (R) authorised nitrogen hypoxia as a backup method if lethal injections are ruled unconstitutional or the drug cocktail shortage means lethal injection drugs are too difficult to source.

“Oklahoma executes murderers whose crimes are especially heinous,” Fallin said. “I support that policy, and I believe capital punishment must be performed effectively and without cruelty. The bill I signed today gives the state of Oklahoma another death penalty option that meets that standard.”

Nitrogen gas works by asphyxiating the prisoner. The gas is applied through a mask or oxygen tent and is usually quick, killing the prisoner in minutes.

The return to nitrogen gas marks Oklahoma as the third state in recent times to change its execution method - after Utah brought back the firing squad and Tennessee reintroduced the electric chair - both clear signs of desperation due to the lethal injection drug cocktail shortage.