Alan Eugene Miller has been put to death by nitrogen hypoxia, which some critics have said is comparable to torture

The US state of Alabama has executed a death row inmate using nitrogen gas, marking the second use of the controversial method, which some critics have claimed is tantamount to torture.

Execution by nitrogen hypoxia involves replacing the oxygen breathed by an inmate with 100% nitrogen. Supporters of the method claim that the person being executed is likely to lose consciousness shortly into the procedure, thus making it more humane than other methods. Other experts, however, have raised concerns that that it could lead to excessive pain and torture, saying there is no way to pinpoint if or when a person loses consciousness when exposed to concentrated nitrogen gas.

On Thursday, Alabama Department of Corrections commissioner John Hamm announced at a news conference that 59-year-old Alan Eugene Miller had been executed using the method and was pronounced dead at 6:38pm local time at Atmore prison. 

According to an Associated Press reporter present at Thursday’s execution, Miller “shook and trembled on the gurney for about two minutes with his body at times pulling against the restraints. This was followed by about six minutes of periodic gulping breaths before he became still.”

In his last words, Miller also reportedly claimed that he “didn’t do anything to be in here” and asked his family and friends to “take care” of someone.

Read more

In his report, Hamm confirmed the two minutes of shaking, stating that involuntary body movements were to be expected as the body was depleted of oxygen. “That is nothing we did not expect,” the commissioner said, affirming that “everything went according to plan and according to our protocol.”

Miller was sentenced for killing three men in a workplace shooting in 1999. In 2022 he asked to be put to death by nitrogen hypoxia but his request was denied at the time. Instead, Miller was to be executed by lethal injection in September 2022 but the attempt was called off after officials said they could not access his veins in time.

The state eventually agreed to execute him by nitrogen hypoxia, but Miller challenged the method after it was used for the first time in January to end the life of death row inmate Kenneth Eugene Smith. During Smith’s execution, witnesses said they saw him shaking and writhing on the gurney for minutes before dying.

In a federal lawsuit, Miller challenged Alabama’s nitrogen hypoxia protocol, claiming it would cause him undue suffering. The lawsuit was settled last month but the terms have remained confidential.