Pharmaceutical companies refusing to sell drugs for lethal injections, combined with several tortuous botched attempts that call into question the procedure’s constitutionality, have made it difficult for US states to carry out executions in recent years. Seeking to fulfill the convictions of their death row inmates in light of the controversies, an increasing number of states are turning to a new execution method – nitrogen hypoxia.
Yet according to scientists, there is little available evidence on whether death by nitrogen gas inhalation is humane.
The method has never been used on an inmate, but Oklahoma, Alabama, and Mississippi have approved its use and are currently developing death penalty protocols around it, according to The New York Times.
As documented by the Death Penalty Information Center, four other states – Alabama, Arizona, California, and Missouri – have legalized use of some type of lethal gas to carry out executions. Lethal injection of paralytic agents followed by a heart-stopping drug is still the primary (in some cases, only) method used by nearly all states that carry out capital punishment. Wyoming allows lethal gas only if an injection is deemed unconstitutional. Missouri’s decision on when to use gas over injection remains unclear, whereas in Arizona and California, inmates can choose the method they prefer.
A total of 11 people have been killed using some type of gas; the most recent of which, in 1999, relied on hydrogen cyanide. The inmate, Walter LaGrand, coughed and convulsed before finally dying 18 minutes after the chamber filled with a poisonous cloud.
Nitrogen hypoxia is reported to avoid the painful side effects leading up to death that may follow caustic gas inhalation or adverse reactions to injected drugs because subjects rapidly lose consciousness and then die from asphyxia.
In theory, replacing all available oxygen with another inert gas will cause death without a reflexive spike in fight-or-flight hormones and gasping for breath that occurs when oxygen is still present, but in low levels. This happens because the mammalian body uses blood carbon dioxide levels to monitor for dangerously low oxygen levels. So, an environment where no oxygen can be breathed in and converted to carbon dioxide, but carbon dioxide that has built up in the lungs can still be breathed out should bring about asphyxia quickly and without panic.
However, the current body of research on nitrogen hypoxia in mammals has led veterinarians and animal health regulators to conclude that the method is unacceptable for euthanizing animals. Several studies have shown that dogs actually take up to five minutes to die despite losing consciousness within one to two. Following this same logic, significantly larger bodied humans would take even longer to die.
Furthermore, whimpering and muscle tremors were noted in the dogs pre-death, likely because maintaining oxygen levels low enough to prevent distress is nearly impossible in practice.
In March, when Oklahoma officials announced their plan to resume halted executions using nitrogen asphyxia, Attorney General Mike Hunter stated the method was being adopted because, “Using an inert gas will be effective, simple to administer, easy to obtain and requires no complex medical procedures.”
Dale Baich, an attorney for several Oklahoma death-row prisoners, told NBC News in response: "Who are the experts on nitrogen and nitrogen hypoxia who will be brought in? What research has the state undertaken to ensure the safety and legality of this new process?"
[H/T: The New York Times]
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