Alabama executed Kenneth Eugene Smith through nitrogen hypoxia on Thursday, marking the first use of the controversial method in the US. Smith was sentenced to death for a 1988 murder.This method has been frowned upon by the UN and the world body has likened it to “torture. However Alabama defended this method and said that the process would be humane.Nitrogen replaces lethal injectionThe 58-year-old was made to breathe pure nitrogen gas by a face mask, depriving him of oxygen until death. Lethal injection has been the predominant execution method in the US since 1982.Alabama had tried executing Smith via injections earlier but failed to connect the IV line in time, forcing them to switch protocols.Nitrogen hypoxia has been criticized as experimental and risks being torturous by rights groups. However, Alabama claimed it would be humane.Last-minute defense by Kenneths lawyerin a last-minute legal fight, Smiths lawyers opposed the use of nitrogen on his client claiming that the Alabama was him as a test subject for an experimental execution method that may violate the constitutional ban on cruel and unusual punishment. However, appeals were dismissed.Smiths lawyers also argued theres scarce research on nitrogen gas executions. They said proper procedures must be established before deploying new methods to minimize suffering.“There is little research regarding death by nitrogen hypoxia. When the State is considering using a novel form of execution that has never been attempted anywhere, the public has an interest in ensuring the State has researched the method adequately and established procedures to minimize the pain and suffering of the condemned person, Smiths lawyers said.Justice Sotomayors warning overlookedDissenting the ruling, Justice Sonia Sotomayor wrote Alabama selected Smith as the guinea pig for an untested protocol after one failed attempt. She hoped he wouldnt be proven right about the risks. “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. The world is watching, ” she wrote in the judgmentSmiths adviser fears moral apocalypseHis spiritual adviser Rev. Jeff Hood said the world watched this impending moral catastrophe, pleading for attention and not normalizing such acts.“The eyes of the world are on this impending moral apocalypse. Our prayer is that people will not turn their heads. We simply cannot normalize the suffocation of each other,” Hood said.Final meetings and mealSmith met the family and his adviser in his final hours. He had T-bone steak with eggs, hash browns, and toast for his last meal.A spokesperson shared that while terrified of potential torture, Smith found peace, believing he was finally getting out.The case put the spotlight on concerns around experimental execution protocols. While courts allowed nitrogen hypoxias use, Sotomayor cautioned against risking needless suffering with untested methods.