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Oklahoma Might Replace Lethal Injections With Nitrogen Gas Chambers

Despite how it sounds, as far as capital punishment plans go, it’s actually a pretty sane choice.
A decommissioned cyanide gas chamber at New Mexico State Penitentiary. ​Photo: Wikimedia Commons​

Executions are on hold in Oklahoma, while ​the US Supreme Court considers whether the state's three-drug protocol constitutes cruel or unusual punishment. Oklahoma Republicans want to make sure the state has another method ready to go if the court rules that lethal injection has to stop and they're proposing death by nitrogen.

Despite how it sounds, as far as capital punishment plans go, it's actually a pretty sane choice.


​The AP reports that there are two separate bills scheduled to be heard in state legislative committees this week that introduce "nitrogen hypoxia" as a backup execution method if the current one is struck down by the Supreme Court. Oklahoma would be the first state to use nitrogen for capital punishment.

For historical reasons, the idea of a gas chamber might seem very cruel and unusual. While lethal gas is on the books in five states, it hasn't been used in the US since 1999. A federal court in California ​found it to be unconstitutional, and reading ​descriptions on the Death Penalty Information Center's website of how lethal cyanide gas executions used to work, it's easy to understand why.​

The pain of suffocation is said to come from a build-up of carbon dioxide in the blood, not the depletion of oxygen.

For execution by this method, the condemned person is strapped to a chair in an airtight chamber. Below the chair rests a pail of sulfuric acid. A long stethoscope is typically affixed to the inmate so that a doctor outside the chamber can pronounce death. Once everyone has left the chamber, the room is sealed. The warden then gives a signal to the executioner who flicks a lever that releases crystals of sodium cyanide into the pail. This causes a chemical reaction that releases hydrogen cyanide gas.

​According to former San Quenton, California, Penitentiary warden, Clifton Duffy, "At first there is evidence of extreme horror, pain, and strangling. The eyes pop. The skin turns purple and the victim begins to drool."


Caryl Chessman, before he died in California's gas chamber in 1960 told reporters that he would nod his head if it hurt. Witnesses said he nodded his head for several minutes.

Nitrogen gas has never been used in an execution before, and while it would certainly be less dangerous for witnesses and the executioners, advocates say that it would be much less painful for the inmate as well.

The pain of suffocation is said to come from a build-up of carbon dioxide in the blood, not the depletion of oxygen. ​According to Slate's Tom McNichol, "people do die accidentally of nitrogen asphyxiation, and usually never know what hit them. (It's even possible that death by nitrogen gas is mildly euphoric. Deep-sea divers exposed to an excess of nitrogen develop a narcosis, colorfully known as "raptures of the deep," similar to drunkenness or nitrous oxide inhalation.)"

Nitrogen asphyxiation is supposed to be so painless that the Australian euthanasia advocate Philip Nitschke sells cylinders of nitrogen to people who want control over the end of their own lives. In ​a video interview with VICE, he said it just takes three minutes or so and he promises that, "provided you're comfortable with the process it will work well." That's more than can be said about lethal injection drugs.

The Supreme Court is examining whether a three-drug protocol that relies on the drug midazolam as an anesthetic, the very drug cocktail that was in the ​botched execution of Clayton Lockett in April 2014.

Lockett visibly struggled, and said things like "the drugs aren't working," for over half an hour until he was pronounced dead of a heart attack. The state determined that a misplaced IV line was responsible, although midazolam was also used in ​remarkably long executions in Ohio and Arizona, which led those respective states to halt executions and reexamine their execution protocol.

In the medical field, midazolam is only used as a sedative, Dr. Tong Joo Gan, the chairman of Stony Brook University's department of anesthesiology, told me. But state departments of justice have been facing a shortage anesthetics like sodium thiopental, which had been approved for lethal injections by the Supreme Court, and in have turned to other drug combinations and considered other methods.

Underneath articles about the death penalty, there are usually three schools of thought: 1. People who think the state shouldn't execute people at all; 2. People who don't see why the state should worry about the well-being of the people they're executing; and 3. People with better suggestions for how the state can perform executions—generally they advocate firing squads. Some have pointed to nitrogen, and Oklahoma legislators have taken note.