“Agony” and “Suffering” as Alabama Experiments with Nitrogen Executions

This article was produced as a collaboration between Bolts and The Intercept.

Alan Miller had spent the six months leading up to his execution confined to his cell. Though Miller was never given an explanation for the heightened captivity, which had over the past few years become routine for people facing execution in Alabama, he used the time to conduct his own research on the state’s plan to kill him with nitrogen gas. 

A Discovery Channel program on scuba diving he’d watched made him especially worried about contracting decompression sickness, otherwise known as the bends. Though Miller’s eyes, nose, and mouth would be covered by a respirator mask, he feared that air would enter his ears and prolong his death — or worse, keep him alive but unable to function. To avoid that risk, he said he asked some prison guards whether he could put tissues in his ears to block them. The guards told him it was above their pay grade and to take it up with the people in charge.

Miller, 59, had been forced to consider the possibility that things could go wrong. Research on killing humans with nitrogen gas — by pumping it through a hose into an industrial respirator mask — was extremely limited, and state officials refused to disclose how they developed the novel method. Alabama is the first and only state to use nitrogen for executions, and had done so just once before. Witnesses described the man, Kenneth Smith, writhing in “seizure-like movements” for two minutes, despite state officials promising he’d lose consciousness “seconds” after the gas started flowing and die after about five minutes. Even the son of the victim was startled by what he saw, telling the New York Times that it conflicted with what state officials had told him to expect. “With all that struggling and jerking and trying to get off that table, more or less, it’s just something I don’t ever want to see again,” he said. Afterwards, Alabama officials offered to help other states adopt execution by nitrogen. 

Leading up to Smith’s execution, one doctor had warned there was a chance the method might not kill him and would inflict such significant brain damage that he’d be left in a vegetative state. 

Miller insisted he’d rather die. “I don’t want to be a vegetable,” Miller told me several times in a thick Southern drawl as we sat across from one another in the dilapidated visitation room at Holman Correctional Facility, a maximum security prison in Atmore that houses Alabama’s death row and execution chamber. 

Miller didn’t have anything to worry about, state lawyers had said. Smith, they wrote in court documents, reacted so violently because he held his breath.

Miller said he had no plans to fight his execution. All he asked was that the state hold up its end of the bargain and give him a quick and peaceful death. Over the summer, he’d agreed to a settlement with the state to help ensure that would happen. The terms were confidential. 

Miller had faced execution before, and survived. 

Almost exactly two years ago, he sat in the same visitation room with his family and lawyers and said what he thought would be his final goodbyes. But he left the execution chamber alive after his executioners failed to establish an IV line for lethal drugs, despite poking him all over his body and hoisting the gurney vertically into the air to suspend him for 20 minutes. He was one of six people in the U.S., and one of three people in Alabama, to survive their execution during the modern death penalty era.

“It’s like déjà vu,” Miller said as he waited again for the state to execute him. Four family members and two lawyers had come to visit. He told me he was irritated that the state was putting them through another execution, and hoped they’d do it right this time. 

His visitors reassured him that everything would be OK. Miller’s brother, who worked as an EMT and firefighter for decades, had plenty of experience wearing a respirator and also witnessing death. “You’ll be just fine,” he told Miller. We all nodded in agreement. 

I would join two of Miller’s lawyers, his brother, sister, and sister-in-law to witness the execution. As we exited the prison around 4:40 p.m., a message brightly painted on an overhang to “Have a great day!” seemed to taunt us. We then loaded ourselves into a white corrections van that took us to a trailer, where we waited for the execution to begin. There, we sat passing the time with inconsequential conversation. Halloween decorations, Taylor Swift, and lawn maintenance were brief distractions from the reality that we were about to watch Miller die. 

If, as the state had suggested, all that Miller needed to do for a quick and painless execution was to not fight it — to willingly breathe in the lethal gas — then Alabama’s second nitrogen execution should have gone smoothly. Instead, once the nitrogen started flowing, we watched from the witness room as Miller thrashed and jerked on the gurney, shaking and pulling at his restraints. On the other side of the glass, John Muench, Miller’s spiritual adviser, stood inside the execution chamber feet away from Miller as he gasped for air.

Muench, who is also a physician, told me he’d seen plenty of death but said Miller’s looked more anguished than most. “We don’t see people jerking around like that while they’re dying normally,” he said. “His face was twisted and he looked like he was suffering.”

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In the years leading up to his execution, Miller was adamant: He didn’t remember committing the crimes that had landed him in this situation in the first place. 

Like the majority of people on death row, Miller endured years of childhood trauma. He also came from a family with a long history of mental illness, according to a 2013 appeal that contained a detailed account of his upbringing. Miller’s great-grandmother once tried to kill her children and was committed to Bryce Hospital, Alabama’s psychiatric facility. Her son, Miller’s grandfather, was admitted to Bryce five times for illnesses such as paranoid type schizophrenic reaction and manic depressive psychosis. Of his sons, three had a history of severe mental illness. One of Miller’s uncles was in prison for murder. 

Miller’s father, Ivan, suffered from paranoia, and always thought that people were plotting against him or trying to harm him — including his own wife, who he thought tried to poison him. Ivan also heaped physical and psychological abuse onto Miller, who he claimed was not his child and called “little red headed bastard.” Family members say that Ivan regularly hit Miller and threatened him with knives and guns, sometimes even shooting bullets into the floors. On one occasion, Miller’s father threatened to take him and his brother out to the woods and see if God would intervene before he killed them. 

Despite Ivan’s abuse, Miller grew up to be a rule-follower and a hard worker. He avoided drugs and alcohol and held several jobs. Ivan, however, still bullied his son, telling him that he wasn’t masculine and calling him gay. Then in July 1999, his family began to notice that something about Miller seemed off. They would later say that Miller, then 34, talked to himself and daydreamed more frequently. Around this time, he also started suffering from constant headaches and ringing in his ears.

On August 5, 1999, Miller drove to work at Ferguson Enterprises, a plumbing and HVAC supply wholesaler, in Pelham, a small city just south of Birmingham. When Miller’s boss, Johnny Cobb, walked into the building, Miller was holding a pistol. “I am sick and tired of people telling rumors on me,” said Miller, according to Cobb, who Miller told to leave the building. When Cobb returned, he saw that two of his employees, Scott Yancy and Lee Holdbrooks, had been shot to death. 

Miller then drove to a previous job at Post Airgas and asked for Terry Jarvis. “Terry you’ve been spreading all kinds of rumors around about me,” Miller said before shooting Jarvis several times, killing him, according to David Adderhold, the store manager, who then pleaded with Miller to spare him. Miller obliged and instructed him to leave.

Police stopped Miller as he drove south on I-65 and arrested him without incident. His pistol, the murder weapon, sat on the passenger seat. When police subsequently interrogated him at the Pelham police station, Miller asked, “I’m being charged with something? … I don’t understand what you’re saying,” according to his appeal. He later said he thought his co-workers had started a rumor he was gay. 

There was no question that Miller had committed the murders.

Still, the state’s psychologist who evaluated Miller said that he had no memory of the shootings and there was a chance that he may have lost touch with reality and dissociated.

Despite this possibility, Miller’s court-appointed lawyers failed to mount a defense during his trial and did little to convince the jury to spare his life because he was mentally ill. Still, some jurors thought he should’ve been shown mercy. He was sentenced to death by a vote of 10–2. (Alabama and Florida are the only states that don’t require all jurors to agree to send someone to death row. Approximately 6 out of every 10 prisoners on death row in Alabama were sentenced to death by a split jury, according to a 2023 report by the NAACP Legal Defense and Educational Fund.)

Later, Miller’s appellate lawyers would argue that his death sentence was unconstitutional. They retained a psychologist who concluded that Miller suffered from PTSD with dissociative features, a common diagnosis for people who have experienced significant trauma. Like the state’s expert, she concluded that Miller was experiencing a dissociative episode at the time of the shooting. 

Even as he waited to be executed, Miller didn’t recall what he had done. After I sat down with him on the morning of his execution, I asked him what he wanted the world to know.

“I didn’t do anything to be in here,” he told me. “If the judicial system had done its job, I would not have been convicted.” 

He elaborated, quickly darting in and out of thoughts and names that were difficult to follow. I asked if he was referring to the shooting. Miller said he didn’t remember it.

During the rest of our conversation, Miller would at times cup his left ear toward me to signal that he was having trouble hearing. His ears had been ringing since he was a kid, which he thought was from his dad hitting him in the head. He’d devised his own methods for tuning it out, like playing video games on his tablet inside his cell. “I try to go blank,” he said.  

Miller recounted returning to his cell after his first execution was called off. The other men on death row were eager to talk with him about what he had just experienced. 

“They asked me what it’s like. I told them you lay there and they stab you,” he recalled nonchalantly. Miller told me that after the failed execution, he just wanted to go to sleep. The experience was not as remarkable as it might have seemed, he said — his father had threatened him with death so often that he was used to it.

Miller’s brother Jeff Carr, who was sitting next to me in the visitation room, said he was stunned when he found out that Miller was in jail for three murders.   

Jeff and his wife Sandra Carr later told me that they thought the death penalty was appropriate for certain people, but that Miller wasn’t one of them. They remembered seeing an unfamiliar look in his eyes after he was arrested, like he had snapped. “That was not the Alan we knew,” Sandra said. “What he told his mother was, ‘They said, I did this, but I don’t remember it.’”

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About 90 minutes after we last saw Miller, prison guards dressed pristinely in sky blue and navy uniforms came to get us from the trailer where we’d been waiting for the execution to start. They led us single-file through a red door and down a cinder-block hallway affixed with a monitor that would alert us in the event of a nitrogen leak. A piece of black tape covered the manufacturer’s name — the state’s attempt to prevent us from knowing whose products were entwined with this new way of killing. We filed into the witness room along with media witnesses, staring ahead into a glass window covered by a curtain. A white license plate hung above the window, instructing us to “STAY SEATED AND QUIET.”

Minutes later, Brandon McKenzie, the prison guard who leads Alabama’s execution team, pulled the blue hospital curtain open, revealing Miller, who was lying strapped to the gurney and tightly enveloped in a white sheet. A blue-rimmed respirator mask covered Miller’s entire face, from his forehead down to his chin. A strip of black tape had also been placed to conceal the mask manufacturer’s name. A hose that ran from the wall behind Miller was connected to a valve on his right side. The setup looked cheap and improvised, like a scene from a low-budget horror movie. 

After Holman warden Terry Raybon read the execution warrant, McKenzie unscrewed the cap to another valve on the left side of Miller’s respirator. The witness room filled with the sound of hissing gas, making it difficult to hear Miller as Raybon held the microphone up to the mask for his last words. “I didn’t do anything to be in here,” Miller said. Some of his words were inaudible, but he mentioned someone not doing their job and asked his sister, Cheryl, to take care of his brother Richard. At one point, Raybon pulled the microphone away from Miller before he was finished talking and had to stick it up to his face again. 

Once Miller finished speaking, Raybon opened the door behind them and disappeared from the execution chamber. McKenzie, the captain of the execution team, remained in the room, checking the mask and feeling its seal around Miller’s face — a step that is supposed to determine whether the mask is tight enough to keep out oxygen. A pulse oximeter monitoring Miller’s oxygen levels was clipped to his ear. After some time, McKenzie then called Miller’s spiritual adviser over to the gurney, who laid one of his hands on Miller’s left leg. It’s unclear when the nitrogen gas started, but I saw Miller’s stomach rise and fall like he was breathing normally. It did not appear that he was attempting to hold his breath. For a second, it seemed as if he might die peacefully after all. 

Then suddenly, Miller started jerking and shaking, struggling against the restraints. While this was happening, he gasped for air and his eyes were open, staring at the ceiling and darting back and forth. This went on for about two minutes before Miller stopped moving. 

Then, for the next five or six minutes, Miller periodically gasped for breath. Some of the gasps were so large that his head lifted off the gurney. His left hand turned blue. 

At 6:32 p.m., about 15 minutes after the gas began to flow, a guard closed the curtain to the execution chamber. Minutes later, a guard unlocked the witness room and told us to exit. 

I again climbed into the van with Miller’s lawyers and family, and we were dropped off in front of Holman. Earlier, an employee told us not to loiter in the parking lot. He apparently meant what he’d said, watching us closely as we walked back to our cars. 

Afterwards, Alabama Department of Corrections Commissioner John Hamm gave a press conference. Asked about Miller’s violent reaction to the gas, Hamm assured reporters that everything had gone according to plan. “There’s going to be involuntary body movements as the body is depleted of oxygen. So that was nothing we did not expect,” he said. 

Alabama Attorney General Steve Marshall gave a similar statement. “Tonight, despite misinformation campaigns by political activists, out-of-state lawyers, and biased media, the State proved once again that nitrogen hypoxia is both humane and effective,” he wrote. Notably, Marshall was not present for the execution. Still, he said it “progressed as planned. After Miller appeared to lose consciousness, his body took some agonal breaths and made slight movements associated with the dying process.”

I emailed my own observations to ADOC and asked whether the agency stood by these statements but did not receive a response.

About 10 days after the execution, Jeff and Sandra Carr, Miller’s brother and sister-in-law, told me the past week had been an emotional rollercoaster. They said they’d been trying to keep it together by sticking to their normal routines, like going to the gym at 5:30 most mornings, a regimen we’d discussed in the prison trailer while waiting to be taken to the execution chamber. 

Having made the eight-hour round trip drive from their home in north Alabama to Atmore two years ago when the state first attempted to execute Miller, they’d known some of what to expect in those final days with him. Jeff said he tried to be strong for his brother and compartmentalize his feelings, even as Miller was worried about them witnessing this next attempt at executing him. “He didn’t want us, I guess, having to watch what was fixing to happen. But you know, we were going to be there,” Jeff said. 

When we discussed what happened that night, Sandra told me that Gov. Kay Ivey and Marshall should have been there to observe the execution for themselves. “If you’re going to sign somebody’s death warrant, you need to be there to witness it and see how it goes,” she said. 

Sandra added, “Nobody should have to witness something like that.”

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I described what I saw to Gail Van Norman, an anesthesiology professor at the University of Washington. She told me that Miller’s reaction was “entirely predictable” and sounded consistent with the reactions of animals suffocated with nitrogen during scientific studies. 

“Yeah, he was awake,” she said. “The textbook says that when you do this to a mammal, they’re going to suffocate, they’re going to know it’s happening. They’re going to try to escape it. They’re going to struggle, they’re going to shake, they’re going to lose their coordination, and they’re going to die a horrible death.” That’s why, Van Norman explained, the American Veterinary Medical Association says that most mammals should not be euthanized with nitrogen. 

It didn’t matter that Miller wanted to cooperate, she said, because nobody actually knows if humans are capable of breathing deeply while being suffocated by nitrogen gas. “Even if they’re capable of it, and they do breathe deeply, I have no reason to believe that it will go any differently,” Van Norman told me. “You’ll still see the gasping, you’ll still see shaking, jerking, discoordination.” 

Miller’s reactions might have looked even worse if he weren’t bound to the gurney and was allowed to roam free, she said. “He’d probably be clawing at the doors and pounding at the windows, trying to get out but he can’t because they’ve tied him down to a gurney, so the only actions left to him are to jerk and grimace and lift his head up and try to do those things.”

Van Norman’s comments reminded me of how intensely Miller had flailed and pulled at his restraints, as if his body would have leapt from the gurney were it not strapped down.  

Marshall’s assessment that Miller had lost consciousness had no scientific basis, Van Norman quipped. She explained that it would’ve been impossible for him to tell because new scientific research on consciousness has shown that there’s actually no way to determine whether someone is unconscious. “Somebody who says that is just saying it off the top of their head or out of wishful thinking, or because they haven’t read the literature,” she said.

Van Norman’s explanation defied everything legislators had promised about execution by nitrogen gas. Alabama lawmakers adopted it as a method in 2018 amid national drug shortages and legal challenges over the constitutionality of the way it carried out lethal injections. State Sen. Trip Pittman, who had sponsored the nitrogen legislation, billed the method as “more humane.” (I sent Pittman, who is no longer in office, an email asking whether he stood by that statement following Miller’s execution, but he never answered.)

There was hardly any science to support the assertion. Former Oklahoma Rep. Mike Christian came up with the idea to execute prisoners with nitrogen after watching a BBC documentary called “How to Kill a Human Being,” which followed a British Parliament member turned journalist in his quest for the perfect execution method. “The process is quick and painless,” Christian told reporters in 2015. “It’s foolproof.” (Christian also did not answer my email asking whether he still believed that.) 

The method, which is scientifically known as nitrogen hypoxia, is supposed to starve the brain of oxygen by replacing it with nitrogen: a colorless, odorless gas that comprises 78 percent of Earth’s atmosphere but is deadly when inhaled on its own. Nitrogen poisoning has killed nearly 100 people since 1992 in accidents at industrial plants, laboratories, and medical facilities. 

Despite authorizing nitrogen hypoxia as an execution method, Oklahoma officials have said they will continue to carry out lethal injections and have no plans to pivot to nitrogen. Mississippi, which approved the method in 2017, has yet to use it either.

In Alabama, death row prisoners were given the option to choose whether they wanted to be executed by the gas over a 30-day period in 2018. But the prisoners and their lawyers say that the state did not make them aware of this choice until five days before the deadline and did not give them enough time to gather information about the method. 

Alabama has refused to publicly release details about how it created its protocol. Legal documents show that officials relied on state employees to test the method, but there’s no record of ADOC testing how a human would react to nitrogen flowing into the mask. The department instead conducted an experiment placing the mask on top of a sheet and towel and measuring oxygen levels. 

Even with limited testing, the state’s expert Dr. Joseph Antognini, a retired anesthesiologist who routinely testifies on behalf of states defending their execution methods, said in court that the system would render Kenneth Smith, the first man executed by nitrogen in January, unconscious within 30 to 40 seconds after the nitrogen began. Antognini did not return my request for comment about the discrepancy between his prediction and what witnesses saw during both nitrogen executions.

Other experts were much less optimistic. Dr. Philip Bickler, an anesthesiologist and director of the Hypoxia Lab at the University of California, San Francisco, said in a recent court filing that there is little scientific research on what happens when humans are forced to breathe in large volumes of nitrogen, but that quickly starving someone of oxygen is likely to cause a feeling of “impending doom.”

Bickler, who has conducted his own research on the effects of nitrogen hypoxia, submitted an affidavit for Miller’s lawyers as they argued that the nitrogen method violated his Eighth Amendment protections against cruel and unusual punishment. In it, he wrote that “any form of execution by nitrogen hypoxia is cruel and inhumane” and warned that Miller’s asthma “would likely prolong the death process.”

Despite these warnings, Marshall, the attorney general, has offered to help other states execute people with nitrogen gas. 

“To my colleagues across the country, many of which were watching last night, Alabama has done it,” Marshall said after Smith’s execution early this year. “And now so can you. And we stand ready to assist you in implementing this method in your states.”

Legislators in Ohio, Louisiana, and Nebraska took Marshall’s lead, introducing bills to authorize the method. In a letter to Nebraska Sen. Loren Lippincott, the sponsor of the state’s bill, Marshall championed the use of nitrogen to execute prisoners, calling media accounts of Smith’s execution “sensational.” Nitrogen, he told the Nebraska lawmaker, was not subject to the drug supply issues that made it difficult to carry out lethal injections and it would be more difficult to fight in court. “Adopting nitrogen hypoxia and allowing condemned killers to elect this method of execution will either expose their litigation games for what they have been, or it will provide them the humane death that they have claimed to be pursuing,” Marshall wrote.

Even with Marshall’s fervent support, the Nebraska bill did not make it out of committee. 

Meanwhile, Louisiana passed legislation authorizing nitrogen executions during a special session on criminal justice called by Gov. Jeff Landry a month after he took office. The state hasn’t killed a prisoner since 2010, but Landry has made it a priority to restart executions. Rep. Nicholas Muscarello, a Republican who drafted the bill, told me shortly after its passage that he was inspired by Alabama’s adoption of nitrogen executions. In the process of introducing his bill, Muscarello said he received a letter from Marshall that “basically supported the form of execution.” He initially agreed to share the letter but later said he was unable to find it.

Calling the death penalty a “tough issue,” Muscarello said he had done his own research on Smith’s execution by nitrogen asphyxiation but did not have an opinion on witness accounts. “I just looked at the legality of it and it was ruled constitutional,” he said. “I’m a lawyer, I wasn’t gonna get drawn into the emotional debate, I wanted to keep them focused on the legal debate.”

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As Alabama officials plan to execute a third person, Carey Dale Grayson, by nitrogen in November, his lawyers have alleged that the method “carries an unacceptable risk of conscious suffocation” and violates the Constitution. They’ll argue their case in a federal hearing this week. 

Their expert, Dr. Brian McAlary, a Virginia anesthesiologist, reviewed Smith’s autopsy, which showed that his lungs were filled with fluid and blood when he died. The finding, he said, was consistent with the condition of someone’s lungs after they’ve been strangled or smothered with a plastic bag. In an affidavit, McAlary concluded that “the risk of undue agony attending this protocol is a medical certainty.”

Grayson’s lawyers had unsuccessfully asked to film Miller’s execution to settle questions over prisoners’ reactions to the gas. Marshall, the attorney general, said there was no need to do so because the media, the same group he called “biased,” would be there to provide an accounting. Hamm, the commissioner, opposed the request, stating that a recording “would severely undermine the solemnity of the occasion.”

Muench, the spiritual adviser and physician who stood next to Miller as he thrashed on the gurney, offered a solution: “I’m sure there’s video of people being waterboarded in this world and my guess is it would look very similar.”

ADOC wouldn’t let Muench join Miller inside the execution chamber until he signed a form acknowledging that he understood the risks of being in a confined space with nitrogen gas and would stand three feet away from the respirator mask after the execution began. 

When it came time to pray with Miller, a guard motioned for Muench to walk forward to the gurney. It was Muench’s understanding that he’d have five minutes with Miller before the gas started flowing. Muench read a psalm and laid a hand on Miller to comfort him. Then, as Muench was reading the second passage they’d agreed on, the Sermon on the Mount, Miller’s head jerked up. 

He said Miller was gray and ashen and his face was twisted.

“I knew suddenly this isn’t going like we planned, and his knees started shaking at that point,” Muench recalled when we spoke after the execution. 

As Miller writhed on the gurney, Muench said it was obvious that the nitrogen gas had been turned on early. “I’m sure he was suffering certainly at the beginning of it, when he was gasping for oxygen,” Muench said. “When he lifted his head up and I could see him, he was definitely gasping.” 

He couldn’t see into the witness rooms on either side of him but saw into another room behind him where men and women dressed in suits and dresses sat. Presumably, they were state officials who had earlier piled out of a black sprinter van into the prison to watch the execution. 

Watching Miller shaking on the gurney, Muench wanted to intervene. “I didn’t feel like there would be anything possible that I could do, but I very much felt, when he started jerking, that we need — we should stop this at some point.”