On Thursday, the US state of Alabama executed a convicted murderer using nitrogen gas. It was the first time a novel method of execution had been used in the United States since the lethal injection, which is currently the most popular technique.
At Holman Prison in Alabama, Kenneth Eugene Smith was put to death by suffocation through nitrogen hypoxia.

Along with Oklahoma and Mississippi, Alabama is one of the three US states that have authorized the use of nitrogen hypoxia as a means of execution.

When a convicted murderer was executed in the United States in 1999, hydrogen cyanide gas was used to carry out the execution.

The person suffering from nitrogen hypoxia is forced to breathe only nitrogen, which deprives them of the oxygen they require to sustain biological functions.

During this method of execution, the prisoner wears a respirator mask over their face, and their lungs are purged with pure nitrogen rather than oxygen.

Smith was executed in about twenty-two minutes, and he seemed to be conscious for a few minutes after that.

He started to thrash and writhe for about two to four minutes, and then his breathing became labored for about five minutes.

His wife and other relatives attended the execution and he gestured towards them, “I love you.” Five journalists were allowed to watch the execution through glass as media witnesses.

Smith’s last words were, “Tonight, Alabama caused humanity to take a step backward,” according to the CBS, whose reporter witnessed the execution.