On Tuesday morning, Kenneth Smith will be moved within the Holman correctional facility in Alabama to the “death cell”, the bluntly named holding unit where condemned prisoners are placed two days before their appointed execution. Smith knows the cell well. He knows its dimensions and the feel of the place. He knows that it sits only about 20 feet from the death chamber where, barring a last-minute reprieve, he will be escorted in handcuffs and leg irons on Thursday before being strapped to a gurney to await his fate. He knows because he has been inside the death cell before. In November 2022, Alabama’s department of corrections put him there as they prepared to execute him by lethal injection. From inside that cell, he said his goodbyes to his mother and his grandson. He had his last meal. Then he was taken to the death chamber where he spent four hours on the gurney as prison officials tried unsuccessfully to find a vein. He was suspended upside down for several minutes as officials worked frantically to secure an IV line. By the time officials admitted defeat and called off the execution, his body was riddled with puncture holes. In the process, Smith was granted entry to an exceptionally elite yet profoundly undesirable club with a membership of just two – Americans who can describe what it is like to survive an execution. Now, just 14 months later, he finds himself about to be put back in the death cell, about to go through it all again. Except this time the protocol is different. Smith, 58, is facing execution by an untested method that has never before been used in capital punishment in the US. It’s a technique that has been rejected on ethical grounds by veterinarians for the euthanasia of most animals other than pigs: death by nitrogen gas. This week, Smith contacted the Guardian from Holman prison and spent his allotted 15 minutes for outside phone calls describing the surreal position in which he now finds himself. He is an execution survivor who is about to go through execution procedures a second time, through an entirely untried method. Is he prepared in himself for his imminent return to the death cell under these circumstances? “I am not ready for that. Not in no kind of way. I’m just not ready, brother,” he said. In the wake of Smith’s failed execution, he has been diagnosed with post-traumatic stress disorder and is being prescribed a cocktail of medications including drugs to control migraines. His prison psychiatrist has recorded that he is suffering from insomnia, anxiety and depression – symptoms often associated with severe trauma. He told the Guardian that he was unable to sleep because of frequent nightmares and the “what-if games you play in the middle of the night”. Following the first execution attempt, he said, he had a recurring nightmare of being escorted back into the death chamber. “All I had to do was walk into the room in the dream for it to be overwhelming. I was absolutely terrified,” he said. “It kept coming up.” Since he was given a second execution date for 25 January, he has had a whole fresh round of nightmares. “I dream that they’re coming to get me,” he said. As his second brush with the execution chamber draws close, he can feel his physical and mental state deteriorate. He said he is “sick in his stomach”, and finds himself retching most days. The nurse in the infirmary has put it down to stress. Smith has an unusual way of conveying the trauma-upon-trauma to which he is being subjected. “They haven’t given me a chance to heal,” he said. “I’m still suffering from the first execution and now we’re doing this again. They won’t let me even have post-traumatic stress disorder – you know, this is ongoing stress disorder.” Smith asked the Guardian to imagine what would happen if a victim of abuse were forced by their abuser straight back into the hostile environment that originally traumatized them. “A person who did that would probably be seen as a monster,” he said. “But when the government does it, you know, that’s something else.” On 18 March 1988, a pastor’s wife in Colbert county, Alabama, Elizabeth Sennett, was stabbed to death in her home. A week later her husband, Charles Sennett, a minister in the Church of Christ, killed himself after detectives began to focus on the fact that he had been having an affair, was deep in debt, and had taken out a life insurance policy on his wife. Smith was one of two people hired through an intermediary for the murder, each paid $1,000. At trial, Smith admitted to having agreed to rough up Elizabeth Sennett but denied intending to kill her. The jury voted by 11 to 1 to give him a life sentence, but they were overruled by the judge who sent him to death row. How does he now look back on his crime, now that he is only days away from a second attempted execution. “Wish I had done things differently,” he said. “One second, one moment in a man’s life. And that’s been the only incident – I’ve not had any incident with officers, not a single fight with inmates, in 35 years. Violence is not who I am.” Yet many people in Alabama, and across the US, believe that because of what he did he deserves all the punishment coming to him. What does he say to them? “I’ve been in prison for 35 years, how have I not been punished? Thirty-five years,” he said. “I have not gone unpunished for 35 years. I have suffered doing this. So has my family.” The new method by which Alabama intends to kill Smith on Thursday is known as nitrogen hypoxia. It involves forcing the prisoner to breathe pure nitrogen, a gas that naturally exists in air, at such high concentrations that it causes oxygen deprivation and eventual death. The idea was initially adopted by Oklahoma, another active death penalty state, in 2015. The scheme was concocted, the Marshall Project discovered, by a criminal justice professor with no medical or scientific training whose main claim to expertise was as a former prosecutor in the western Pacific Ocean islands of Palau – one of the smallest countries in the world, population 18,000. Having been through four hours of an attempted judicial killing by lethal injection, Smith is now looking into the unknown. Asked what he fears most about possibly being administered nitrogen gas in the first execution of its type, Smith at first made a generic argument. “I fear that it will be successful, and you will have a nitrogen system coming to your state very soon. That’s what I’m worried about.” Mercy really doesn’t exist in this country when it comes to difficult situations like mine Smith has a point. Though it has never been carried out, execution by nitrogen is on the books in Alabama, Mississippi and Oklahoma, and other states including Louisiana are considering it. But that’s a rather rarified fear for someone so close to a return to the death chamber. Doesn’t he have personal fears? “I try not to think about it. I try not to read too much,” he said. Then he added: “Throwing up in that mask. Because if I do, brother, nobody’s gonna help me. I’m gonna drown on my own vomit, and my wife will have to sit there and watch.” There has been a lot of discussion about the mask through which Alabama plans to pipe nitrogen into him. A federal judge described the contraption in a court document as an “industrial grade, continuous flow supplied-air respirator mask with an adjustable five point harness system and a pliable, double flange rubber seal that would tightly fit and hold the mask over the entirety of the wearer’s face – including eyes, nose, mouth and chin”. The danger, critics have warned, is that if the seal is not perfect, oxygen could seep into the mask and lead to a prolonged and distressing death. It is also one thing to offer an industrial mask to a worker for his or her self-protection, it is another thing entirely to force it onto a person who might struggle and resist simply to stay alive. “I’m not participating,” Smith said, referring to his own execution. “I’m not gonna, you know, grab the mask and strap it on, I’m not gonna help them.” The idea that he would co-operate with the department of corrections in his own demise reminds Smith, he told the Guardian, of what guards said to him as they were trying to stick a giant needle under his collar bone during the failed 2022 execution. Smith recalled that he cried out in excruciating pain. As he did so, the deputy warden who was tightly gripping his head leaned over to him and told him to relax. “Kenny, this is for your own good,” he said. One of Smith’s greatest anxieties as he braces himself for what’s coming is having to say goodbye for a second time to those he loves most. Should the execution go ahead, his wife Deeanna will be with him in the witness section of the death chamber, but he will have to have a final word in advance with his 78-year-old mother Linda – “my little mama” – and his 12-year-old grandson Crimson, named after the University of Alabama football team. “That is so, so hard. I’m putting them through this again, and I don’t know how we do it,” he said. “I got a tough bunch with me, you know my family are amazing. We’ll get through it.” His lawyers are making eleventh-hour appeals to federal judges, arguing that both the proposed use of nitrogen and the fact that Smith has already been traumatized by the failed attempt to kill him are forms of cruel and unusual punishment barred under the US constitution. They are pressing for a stay of execution, though at this late stage the sand in the hourglass is running out. As the buzzer sounds marking the end of 15 minutes, I squeeze in one last question. If he had the chance to say something to people at large, what would it be? “You know, brother, I’d say, ‘Leave room for mercy’. That just doesn’t exist in Alabama. Mercy really doesn’t exist in this country when it comes to difficult situations like mine.”