Calls continue to mount for officials to halt the execution of a death row inmate in Alabama, who is scheduled to be put to death later this month using nitrogen hypoxia — a controversial method that international human rights experts have denounced for its potential to cause severe and unnecessary suffering.

"We are concerned that nitrogen hypoxia would result in a painful and humiliating death," said a group of experts in a statement issued Wednesday by the United Nations. The experts — Morris Tidball-Binz, Alice Jill Edwards, Tlaeng Mofokeng and Margaret Satterthwaite — are part of the Human Rights Council's special procedures program, where independent specialists work on a volunteer basis to investigate and advise on human rights issues across the world.

The human rights experts have appealed directly to U.S. federal authorities as well as authorities in Alabama, where they asked for a review of the state's execution protocol, according to the U.N.  Alabama is one of three U.S. states that allow nitrogen hypoxia as an alternative means for execution, alongside Oklahoma and Mississippi, although the Alabama execution would be the first in the country to actually happen using the method. 

"This will be the first attempt at nitrogen hypoxia execution," experts said in their U.N. statement, and noted that there is "no scientific evidence to prove" that execution by nitrogen inhalation will not cause "grave suffering."

Alabama released its first execution protocol for nitrogen hypoxia in August, after authorizing it as a legal option for capital punishment in 2018 amid an ongoing shortage of lethal injection drugs. The method is designed to asphyxiate the condened inmate by forcing them to breathe pure nitrogen, or toxically high concentrations of nitrogen, through a gas mask. It is untested, and critics have noted that setting off a stream of nitrogen gas in the death chamber could even threaten the health of other people in the room.

The inmate scheduled to be executed this way in Alabama is Kenneth Eugene Smith, who was convicted in the 1998 killing of a preacher's wife as part of a murder-for-hire plot. The state attempted to execute Smith the first time in November 2022, by lethal injection, but the execution was called off after prison staff failed to locate a suitable vein to inject the drugs, after trying for about an hour, said the Alabama Department of Corrections commissioner at the time, the Associated Press reported. Alabama has botched four lethal injections since 2018, and Smith is one of two death row inmates who survived.

Smith is now scheduled to be executed on Jan. 25.

Human rights experts warned that using nitrogen hypoxia for a death row execution likely violates a body of principles adopted by the U.N. to protect detained people and an international treaty against torture that U.S. signed decades ago. The pact, however, inlcudes a clause negating the treaty's application to capital punishment as long as it is carried out in compliance with the Constitution. The U.S. Supreme Court has ruled that the Eighth Amendment, which prohibits cruel and unusual punishment, does not necessarily prohibit the death penalty.

Rev. Jeffrey Hood, a spiritual adviser to death row inmates, told CBS News in December that he had recently filed a lawsuit challenging executions by nitrogen gas on the grounds it prevents him from giving proper support to prisoners like Smith by putting the preacher himself in danger. Thwarting the duties of a spiritual adviser in the death chamber would go against a Supreme Court ruling protecting those rights, he said.

Hood said in the lawsuit that Alabama's use of nitrogen hypoxia as an execution method "presents potentially significant dangers to his own life, and violates the religious liberties of both himself and Mr. Smith."

Alabama's execution protocol for nitrogen hypoxia is heavily redacted. It outlines safety procedures in place for staff performing the execution and acknowledges some risks that come with handling nitrogen gas. The protocol says inmates executed by nitrogen hypoxia will be denied a spiritual adviser or alternate spiritual adviser in the death chamber, unless the spiritual adviser signs an acknowledgment form. 

—Alyssa Spady contributed reporting.

In:
• Alabama
• United Nations
• Execution

Emily Mae Czachor

Emily Mae Czachor is a reporter and news editor at CBSNews.com. She covers breaking news, often focusing on crime and extreme weather. Emily Mae has previously written for outlets including the Los Angeles Times, BuzzFeed and Newsweek.

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