On January 25, 2024, Alabama executed Kenneth Smith using nitrogen hypoxia, a first in American history. Though state attorneys had assured courts that the method would cause “unconsciousness in seconds,” witnesses reported that Mr. Smith appeared awake for several minutes after the nitrogen gas began. They observed that he “shook and writhed” for at least four minutes before breathing heavily for another few minutes. “This was the fifth execution that I’ve witnessed in Alabama, and I have never seen such a violent reaction to an execution,” said media witness Lee Hedgepeth. Department of Corrections Commissioner John Hamm said the nitrogen gas flowed for about 15 minutes. Mr. Smith, 58, was pronounced dead 32 minutes after the curtains opened on the execution chamber.

Mr. Smith would not have been sentenced to death today. His jury voted 11-1 in favor of a life sentence, but the judge overrode the recommendation and imposed a death sentence in a practice now outlawed nationwide. Mr. Smith also survived a botched lethal injection attempt in November 2022 in which Alabama officials strapped him to the gurney for four hours and inserted needles into his muscles. He was one of the few people in history to face execution twice, and experienced severe PTSD symptoms leading up to his second execution date.  

The Supreme Court denied a stay of execution and certiorari review to Mr. Smith over the dissents of Justices Sotomayor, Kagan, and Jackson. “Having failed to kill Smith on its first attempt, Alabama has selected him as its ‘guinea pig’ to test a method of execution never attempted before,” wrote Justice Sotomayor. Justice Kagan, joined by Justice Jackson, emphasized the risk of Mr. Smith choking on his own vomit as he was deprived of oxygen. Prison officials did not allow Mr. Smith to eat in the ten hours before the execution or drink in the four hours before. Medical experts had also raised the risk of nitrogen hypoxia putting a prisoner into a vegetative state or harming staff and advisors in the execution chamber if the gas leaked. “With deep sadness, but commitment to the Eighth Amendment’s protection against cruel and unusual punishment, I respectfully dissent,” Justice Sotomayor wrote. “The world is watching.”  

Tonight Alabama causes humanity to take a step backwards,” Mr. Smith said in his last words. “I’m leaving with love, peace, and light.” He signed “I love you” to his family after the gas mask was put on.  

See DPIC’s previous reporting on Mr. Smith’s legal history and first execution date, botched first execution, and legal challenges to nitrogen hypoxia 

This story has been updated to reflect new information regarding Mr. Smith’s execution. 


Aliss Higham, Kenneth Smith’s Final Words Before Alabama Execution, Newsweek, January 26, 2024; Nicholas Bogel-Burroughs and Abbie VanSickle, Alabama Carries Out First U.S. Execution by Nitrogen, The New York Times, January 25, 2024; Marty Roney, Nitrogen gas exe­cu­tion: Kenneth Smith con­vuls­es for four min­utes in Alabama death cham­ber, Montgomery Advisor, January 25, 2024; Smith v. Hamm (2024) dis­sents; Lee Hedgepeth, The human­i­ty of Kenneth Eugene Smith, Tread, January 24, 2024; Cybele Mayes-Osterman, Nitrogen hypox­ia: Why Alabama’s exe­cu­tion of Kenneth Smith stirs eth­i­cal con­tro­ver­sy, USA Today, January 232024