On Thursday, the 25th of January, 2024, the State of Alabama carried out the first execution in world history using nitrogen hypoxia when 58-year-old Kenneth Eugene Smith was put to death at the William C. Holman Correctional Facility in Atmore, Escambia County. Smith had spent over twenty-seven years on death row following his conviction for the 1988 contract murder of a preacher’s wife in Colbert County.
His case attracted unprecedented international scrutiny, not only because it marked the introduction of an entirely novel and untried execution method, but also because Alabama had previously attempted—and failed—to execute him by lethal injection fourteen months earlier.
The Crime
The murder took place on Friday, the 18th of March, 1988, in the rural community of Colbert Heights, near Tuscumbia in northwest Alabama. The victim was 45-year-old Elizabeth Dorlene Sennett, the wife of the Reverend Charles Sennett, pastor of the Westside Church of Christ in Sheffield.
Unknown to his congregation, Reverend Sennett had accumulated substantial debts and had taken out an insurance policy on his wife’s life. Intent on securing the payout, the reverend engaged a tenant farmer named Billy Gray Williams to arrange her murder. Williams in turn hired two men—22-year-old Kenneth Eugene Smith and 19-year-old John Forrest Parker—offering to pay each man $1,000 for carrying out the killing.
On the morning of the murder, Smith and Parker drove to the Sennett residence under the pretext that the pastor had permitted them to look over the grounds for hunting. Once admitted to the home, the two men launched a sustained attack on Mrs Sennett. She was struck repeatedly with a heavy fire iron and other domestic implements before being stabbed eight times in the chest and neck. The residence was ransacked and several items were taken to give the appearance of a botched burglary.
Reverend Sennett returned home later that day and summoned authorities, claiming to have discovered his wife’s body. However, within a week, investigators uncovered discrepancies in his story. Upon learning that he had become the primary suspect, Reverend Sennett called an emergency meeting of his church elders, denied his involvement, and then drove to his pickup truck behind his house, where he died by suicide by gunshot on the 25th of March, 1988.
Subsequent investigations quickly led police to Williams, and through him to Smith and Parker. A search of Smith’s residence recovered a videocassette recorder taken from the Sennett home.
Trials and Sentences
All three conspirators were indicted for capital murder. Billy Gray Williams was convicted in 1989 and received a sentence of life imprisonment without parole; he died in prison in November 2020. John Forrest Parker was convicted, sentenced to death, and executed by lethal injection in Alabama on the 10th of June, 2010.
Kenneth Eugene Smith was initially tried in Colbert County in 1989. The jury found him guilty of capital murder and recommended death, a sentence confirmed by the trial judge. However, in December 1995, the Alabama Court of Criminal Appeals overturned the conviction on appeal due to improper racial discrimination by the prosecution during jury selection (Batson violation).
Smith was retried in 1996. The second jury again convicted him of capital murder, but voted 11–1 to recommend a sentence of life imprisonment without parole. Under Alabama law at that time, the presiding judge possessed the statutory power of “judicial override”—the authority to disregard a jury’s sentencing recommendation. The trial judge overrode the jury’s advisory verdict and imposed the death penalty. (Alabama abolished the judicial override practice in 2017, but the repeal was not made retroactive to inmates already sentenced under it.)
The Failed Lethal Injection (November 2022)
Smith was initially scheduled to be executed by lethal injection on the 17th of November, 2022. That evening, following the late lifting of a federal stay, prison officials escorted Smith into the execution chamber at Holman Prison shortly after 10:00 p.m.
For nearly an hour, the execution team attempted to establish intravenous access. Medical personnel inserted needles into both of Smith’s arms and hands, and subsequently attempted a central venous line procedure in his collarbone area. As midnight and the expiration of the death warrant approached without viable venous access having been secured, the execution was officially called off at 11:21 p.m.
Smith was returned to death row, having sustained multiple puncture wounds. The incident was the second execution aborted by Alabama in two months due to intravenous access failures, leading Governor Kay Ivey to pause all executions in the state pending an internal review.
Following the botched attempt, Smith brought a civil rights lawsuit challenging any further attempts to execute him by lethal injection. In early 2023, the State of Alabama settled the litigation by agreeing that it would not attempt to execute Smith via lethal injection again, leaving nitrogen hypoxia—authorized by the state legislature in 2018 as a backup method—as the only remaining statutory alternative.
Appeals and Legal Challenges to Nitrogen Hypoxia
In August 2023, the Alabama Attorney General petitioned the state Supreme Court to set an execution date using the state’s newly published nitrogen hypoxia protocol. In November, Governor Ivey set the execution date for the 25th of January, 2024.
Smith’s attorneys immediately challenged the protocol in federal court, contending that administering nitrogen gas through a full-face industrial mask presented grave constitutional risks under the Eighth Amendment. Medical experts for the defence argued that any breach in the mask seal could draw in oxygen, prolonging suffocation, or that involuntary vomitus inside the mask could cause death by choking. Concerns were also raised by United Nations human rights monitors.
Nevertheless, on the 10th of January, 2024, a federal district judge ruled that Alabama’s protocol was constitutionally permissible. The Eleventh Circuit Court of Appeals and the United States Supreme Court declined to intervene, with the high court issuing its final denial of a stay on the afternoon of the 25th of January, 2024.
The Execution
For his final meal, Smith requested a T-bone steak, hash browns, toast, and eggs. Because prison officials were concerned about the risk of aspiration should nausea occur under the mask, he was not permitted solid food after 10:00 a.m. on the day of execution.
Smith was escorted into the execution chamber at Holman shortly before 7:30 p.m. on Thursday, the 25th of January, 2024. He was strapped to the gurney in an upright, slightly angled position. An airtight, full-face respirator mask—covering him from forehead to chin—was fitted securely to his head and connected to clear plastic hoses feeding from nitrogen cylinders outside the chamber.
When the blinds to the witness room were raised at 7:53 p.m., official witnesses, media representatives, and members of both the Sennett family and Smith’s family were seated. His spiritual adviser, the Reverend Jeff Hood, stood inside the chamber near the gurney.
When asked if he had any final words, Smith stated:
“Tonight Alabama causes humanity to take a step backwards. I’m leaving with love, peace and light. Thank you for supporting me. Love, love all of you.”
He then made an “I love you” sign with his hands toward his wife and family behind the viewing glass.
At approximately 7:57 p.m., the warden ordered the flow of pure nitrogen gas to begin. According to media witnesses, Smith remained conscious for roughly two minutes. Between 7:58 p.m. and 8:02 p.m., he appeared to struggle against his restraints; he began shaking and writhing violently on the gurney, followed by several minutes of heavy, laboured gasping and heaving of the chest. The movements gradually diminished, and all visible respiration ceased around 8:08 p.m.
The flow of nitrogen continued through the mask for fifteen minutes in accordance with state guidelines. The curtains to the witness room were closed at 8:15 p.m., and Kenneth Eugene Smith was formally pronounced dead at 8:25 p.m. Central Time. He was 58 years of age.
Following the execution, Alabama Department of Corrections officials characterised the procedure as textbook, stating that any convulsions observed were involuntary muscular responses to anoxia. Conversely, defence lawyers and abolitionist observers described the event as prolonged and distressing.
Smith became the first person executed in the United States in 2024, and the first condemned prisoner anywhere in the world to be put to death by inert gas asphyxiation.
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