US executes prisoner with nitrogen, in the first new execution method in decades.

Reuters - The US state of Alabama executed convicted murderer Kenneth Smith on Thursday, who held his breath in vain as officers asphyxiated him with nitrogen gas, the first use of a new method of capital punishment since lethal injections began to be administered in the US four decades ago.

Smith, convicted of a 1988 murder for hire, was a rare prisoner to survive an execution attempt. In November 2022, Alabama authorities aborted his execution by lethal injection after struggling for hours to insert an intravenous needle into his body.

The state called its new, closely monitored protocol "the most painless and humane method of execution known to man." It stipulated that Smith would lose consciousness in less than a minute and die soon after, although witnesses on Thursday said it appeared to take several minutes longer.

Alabama has touted asphyxiation as a simpler alternative for prison systems struggling to find veins or the medications needed for lethal injections.

Human rights groups, United Nations torture experts and Smith's lawyers tried to stop the act, saying the method was risky, experimental and could lead to an agonizing death or non-fatal injury.

On Smith's second and final trip to the execution chamber on Thursday, officers strapped him to a gurney and strapped a commercially produced industrial safety mask to his face. A canister of pure nitrogen was attached to the mask, which, as it flowed, deprived him of oxygen.

The execution began at 19:53 p.m. (22:53 GMT) and Smith was pronounced dead at 20:25 p.m. (23:25 GMT), prison officials said.

Smith appeared to remain conscious for several minutes after the nitrogen was activated, according to five journalists who were allowed to watch the execution through glass as media witnesses. Although the mask was also attached to the gurney, he began shaking his head and writhing for about two minutes, and then could be seen breathing deeply for a few minutes before his breathing slowed and became inaudible, the witnesses said.

"It looked like Smith was holding his breath as long as he could," said Alabama Correctional Commissioner John Hamm at a press conference. "He struggled a little against the restraints, but it was an involuntary movement and agonizing breathing. So all of that was expected."

Reverend Jeff Hood, Smith's spiritual advisor, was by his side during the execution and said that prison officials in the room "were visibly surprised at how badly the situation had developed."

"What we saw were minutes of someone fighting for their life," Hood, who participated in his fifth execution in the last 15 months, told reporters. "We saw minutes of someone struggling back and forth. We saw spit. We saw all sorts of material from their mouth build up on the mask."

Before the nitrogen was switched on, Smith made a lengthy final statement that began: "Tonight, Alabama made humanity take a step back."

His wife and other relatives attended, and he gestured toward them. "I leave with love, peace, and light," he said, according to media witnesses. "I love you all."