One Year On (and with Executions Looming), What We Know about Nitrogen Executions—and Whether It Matters

Absent the kind of miracle rarely granted in capital cases, Demetrius Frazier will be gassed to death today. While he becomes the first inmate to die in Michigan’s custody(1), he’ll become the fourth executed by the latest incarnation of gassing undesirables.

Today’s execution comes just over a year after Alabama’s (and the world’s) first execution by nitrogen gas, the killing of Kenneth Smith on January 24th, 2024; Alabama has carried out two subsequent executions via nitrogen hypoxia between then and today. While this is still a small sample size, we now have a rough idea of how a nitrogen gas execution goes—or rather, two rough ideas: one from the state and one from witnesses.

A Brief History of Better Killing Through Chemistry

While the parallels between inert gas executions and more infamous methods of intentional asphyxiation shouldn’t be ignored, there are important distinctions between this and the infamous gas chambers of old. Hydrogen cyanide, the gas used in Nazi and pre-Furman American execution chambers (and recently revived by Arizona), works by interrupting cells’ metabolism of oxygen, a process that can cause intense pain. Nitrogen, by contrast, is inert, and doesn’t interact with the chemoreceptors that work to keep blood gases balanced. According to the theory of inert gas asphyxiation, a person could comfortably breathe an inert gas until their oxygen levels were completely depleted, at which point they’d lose consciousness; a history of industrial accidents appears to back them up.

Asphyxiation by inert gas had been theorized as a means of “quiet death” for decades. Like lethal injection before it, however, nitrogen hypoxia didn’t really take off until states suddenly found themselves needing a new execution method. Following the disastrous execution of Clayton Lockett in 2014—and, perhaps more importantly, the end of easy access to execution drugs—Oklahoma commissioned a report from a three-person team of academics. None of the three had any background in medicine or the life sciences, and the report leaves a lot to be desired in terms of scientific reasoning: the study it relies upon to conclude a lack of “physical discomfort associated with inhaling the pure nitrogen” is a small 1963 study that didn’t measure discomfort. Later opponents would point out animal studies that resulted in widespread bans on its use in euthanizing close relatives to humans; while the committee relied heavily on the concept of nitrogen suicides, a pioneer in assisted suicide by asphyxiation described himself as “appalled and devastated“ after inspecting Alabama’s closed-mask setup.

This didn’t stop the idea from taking root in both Oklahoma and elsewhere, including the legal briefs of capital defendants themselves. Required by case law to suggest an alternative execution method in order to challenge the state’s protocol, Missouri inmate Russell Bucklew proposed a nitrogen-based execution. Writing in 2019, Justice Gorsuch was skeptical, pointing out that existing research didn’t answer “essential questions like how nitrogen gas should be administered (using a gas chamber, a tent, a hood, a mask, or some other delivery device); in what concentration (pure nitrogen or some mixture of gases); how quickly and for how long it should be introduced; or how the State might ensure the safety of the execution team, including protecting them against the risk of gas leaks.“

However, the state’s burden to demonstrate the constitutionality of its execution protocol is substantially lower than defendants proposing alternative methods; the Court has never ruled that an execution method violates the Eighth Amendment’s ban on cruel and unusual punishment. When Alabama prepared to execute Smith with several of these questions still unanswered, only Sotomayor dissented.

Alabama Says One Thing about Its Executions; Witnesses Say Another

According to Alabama Attorney General Steve Marshall, Smith’s execution was “textbook.“ Witnesses disagreed:

Alabama’s immediately attempted to counter the narrative: Department of Corrections Commissioner John Hamm said Smith’s seeming agony was merely “agonal breathing”, without revealing what medical background he was relying on for an assessment that contradicts eyewitness testimony (agonal breathing refers to an occasional gasp amid bouts of apnea). Coming from the state that didn’t see the problem with puncturing a man’s spleen during an IV attempt, this explanation was in character but unconvincing.

Alan Lee Miller’s execution, which proceeded following a settlement in litigation that revealed further troubling details from Smith’s autopsy, resulted in more of the same. Marshall similarly dismissed Miller’s seeming agony as “agonal breathing” (though in addition to having no more medical background than Hamm, witness and Bolts reporter Lauren Gill noted he wasn’t even there). After the execution of Carey Dale Grayson, however, the state changed its tune; this time, Hamm declared that several minutes of “writhing and gasping“ were “all show.“ (How Grayson could put on a show when, according to the state’s own physician witness, he should have been unconscious in 30 seconds, Hamm apparently did not elaborate.)

There’s Nothing Stopping Nitrogen Executions in Alabama, but “Progress“ Has Slowed Elsewhere

Alabama’s track record on both executions and transparency may be questionable, but there’s very little that can hold their feet to the fire. With the Supreme Court apparently prepared to greenlight any execution method and the most execution-friendly federal government in decades, the state has a free hand when it comes to capital punishment. The only speed-bump of resistance might be the gas distributors’ reluctance, but as we’ve covered before, gas supplies are far easier to find than drugs—which haven’t been all that hard to find, legality be damned.

The method’s uptake has slowed, however, in other states. While three other states have authorized the use of nitrogen hypoxia, none have taken concrete steps to making it a reality, and bills in Ohio and Nebraska have stalled out. What was poised to be the next big thing in state-sponsored homicide may end up a footnote in an ugly history.

(1) Michigan has never authorized the death penalty; Frazier was serving a life sentence there when he was extradited to Alabama for the murder of Pauline Brown.