In a scathing dissent, Justice Sonia Sotomayor wrote that there is “mounting and unbroken evidence” that the method is unconstitutional.

An Alabama inmate convicted of killing a man over a drug debt was set to be executed Thursday evening in the state’s latest death sentence carried out with nitrogen gas.
Anthony Boyd, 54, was sentenced to death for his role in killing Gregory Huguley in Talladega County more than 30 years ago. Prosecutors said Huguley was doused in gasoline and set on fire after he didn’t pay for $200 worth of cocaine.
Boyd is scheduled to be executed Thursday evening at William C. Holman Correctional Facility in southern Alabama.
The method that Alabama began using last year uses a gas mask strapped over the inmate’s face to replace breathable air with pure nitrogen gas, causing the person to die from lack of oxygen.
The U.S. Supreme Court on Thursday afternoon denied Boyd’s request to stay the execution and instead let him die by firing squad. Justice Sonia Sotomayor authored a scathing dissent joined by Justices Elena Kagan and Ketanji Brown Jackson.
Sotomayor, citing witness description of past nitrogen gas executions, wrote that there is “mounting and unbroken evidence” that the method is unconstitutional. She wrote that “allowing the nitrogen hypoxia experiment to continue” fails to protect the dignity of the nation.
Alabama has maintained that any shaking or gasping exhibited by inmates during nitrogen gas executions are largely involuntary actions caused by oxygen deprivation. Nationally, the method has been used in seven executions: six times in Alabama and once in Louisiana.
A jury convicted Boyd of capital murder during a kidnapping and recommended by a vote of 10-2 that he receive a death sentence for his part in the killing of Huguley, whose burned body was found Aug. 1, 1993, in a rural Talladega County ballfield. Prosecutors said Boyd was one of four men who kidnapped Huguley the prior evening.
Boyd was convicted after a prosecution witness, testifying as part of a plea deal, said Boyd taped Huguley’s feet together before another man doused him in gasoline and set him on fire.
Boyd has maintained his innocence.
“I didn’t kill anybody. I didn’t participate in any killing,” Boyd said by telephone during an Oct. 8 news conference organized by supporters.
Defense lawyers said he was at a party on the night that Huguley was killed and that the plea deal testimony is unreliable. Boyd’s supporters placed multiple billboards across the state urging Alabama to halt the execution.
Alabama Attorney General Steve Marshall’s office in an earlier statement said that Boyd’s case has been litigated for three decades and, “he has yet to provide evidence to show the jury got it wrong.”
Boyd has been on Alabama’s death row since 1995. He is chairman of Project Hope to Abolish the Death Penalty, an anti-death penalty group founded by men on death row.
Shawn Ingram, the man prosecutors accused of pouring the gasoline and then setting Huguley on fire, was also convicted of capital murder. He is also on death row.
The Rev. Jeff Hood, who was the spiritual adviser at the first nitrogen execution, will serve as Boyd’s spiritual adviser. Hood, who has also witnessed multiple lethal injections, said that the nitrogen execution was “most viscerally horrible by far.”