What is nitrogen hypoxia? Alabama’s untested execution method could be dangerous for everyone in the room

On 25 January, Alabama Department of Corrections (ADOC) officials will strap Kenneth Eugene Smith to a gurney in Holman Correctional Facility and pump his lungsfull of pure nitrogen.

Having survived one horribly botched execution, Smith faces being put to death by a wholly untested method that has been decried as inhumane by death penalty experts and deemed unfit even for killing most mammals.

So experimental is “nitrogen asphyxia” as a form of capital punishment that ADOC has required Smith’s spiritual adviser Reverend Jeff Hood to sign a waiver that forces him to maintain a distance of at least three feet (.9m) during the execution.

The legal document states that it would be possible, though “highly unlikely”, that a hose supplying nitrogen to Smith's mask detaches from his face, filling an area around him with the potentially deadly odourless, tasteless, invisible gas.

“They’re asking for my trust,” Dr Hood toldThe Independent in an interview. “The problem is they have a history of being untrustworthy.”

Kenneth Eugene Smith is due to become the first person to be executed by nitrogen asphyxia in January

Dr Hood believes that depriving him of the sacred right to anoint Smith with oil and administering his last rites is unconstitutional as it infringes on his religious liberties.

On 13 December, he filed a lawsuit in Alabama contesting the state’s right for him to remain at a distance during the execution.

The Texas-based anti-death penalty activist has counselled dozens of death row prisoners and attended four executions in the past year in Oklahoma, Texas and Alabama.

He says Alabama stands out for its incompetence and bloodlust.

“I can tell you without a doubt that the state of Alabama is the most