Washington: The White House said Friday it was "deeply troubled" by the first-ever execution in the United States using nitrogen gas, an untested method which also drew condemnation from the United Nations and European Union.
The southern state of Alabama put Kenneth Eugene Smith, a 58-year-old convicted murderer, to death on Thursday by pumping nitrogen gas into a facemask, causing him to suffocate.
"The use of nitrogen gas - it is troubling to us," White House spokeswoman Karine Jean-Pierre told reporters. "We are deeply troubled by it."
Recent executions in the United States have been carried out by lethal injection but Alabama and two other states - Oklahoma and Mississippi - have authorized the use of nitrogen gas.
Alabama Attorney General Steve Marshall on Friday defended the decision to put Smith to death through nitrogen asphyxiation saying the execution had been carried out in a "professional manner."
"We will definitely have more nitrogen hypoxia executions in Alabama, I believe that number is 43," Marshall told reporters. None are currently scheduled for this year.
After the nitrogen gas was administered, Smith "began writhing and thrashing for approximately two to four minutes, followed by around five minutes of heavy breathing," local news outlet AL.com reported.
Alabama Department of Corrections Commissioner John Hamm said Smith appeared to be "holding his breath as long as he could" and there was "involuntary movement" and gasping.
UN human rights chief Volker Turk, the EU and US civil liberties groups expressed concern about the manner of Smith's execution, which has reignited debate about the use of capital punishment.
"This novel and untested method of suffocation by nitrogen gas may amount to torture, or cruel, inhuman or degrading treatment," Turk said.
Ravina Shamdasani, spokeswoman for the UN human rights office in Geneva, said Smith was "clearly suffering."
Rather than using such untried methods to conduct executions, "let's just bring an end to the death penalty," Shamdasani said. "This is an anachronism that doesn't belong in the 21st century."
A spokesperson for the 27-member EU, which opposes the death penalty, denounced the method of execution as "a particularly cruel and unusual punishment."
Yasmin Cader of the American Civil Liberties Union said Smith "should have never been killed, let alone in such a gruesome manner.
"It's past time for our country to put an end to the death penalty instead of inventing new and more heinous ways of carrying it out," Cader said.
Jean-Pierre, the White House spokeswoman, noted that President Joe Biden suspended federal executions after taking office.
"The president has long said, and has had deep, deep, deep, concerns with how the death penalty is implemented and whether it is consistent with our values," she said.
Smith was sentenced to death for the 1988 murder-for-hire of Elizabeth Sennett, a pastor's wife.
He and an accomplice, John Parker, were each paid $1,000 to kill Sennett. Parker was executed by lethal injection in 2010.
Smith was subjected to a botched execution attempt in November 2022, when prison officials were unable to set intravenous lines to administer a lethal injection.
The US Supreme Court rejected his last-minute appeals for a stay of execution.
Smith's last words Thursday were, "Tonight, Alabama caused humanity to take a step backward," according to the local CBS affiliate. "I am leaving with love, peace and light."
The last US execution using gas was in 1999 when a convicted murderer was put to death using hydrogen cyanide gas.
There were 24 executions in the United States in 2023, all of them carried out by lethal injection.
Speaking to reporters after the execution, Elizabeth Sennett's son Mike said it had been a "bittersweet" day for his family, as "nothing that happened here today is going to bring Mom back."
According to a recent Gallup Poll, 53 percent of Americans support the death penalty for someone convicted of murder, the lowest level since 1972.
Capital punishment has been abolished in 23 states, while the governors of six others - Arizona, California, Ohio, Oregon, Pennsylvania and Tennessee - have put a hold on its use.