Louisiana is preparing to carry out its first execution in 15 years using a gassing method that is banned under the state’s own laws for euthanizing cats and dogs.

Barring a last-minute intervention by the US supreme court, Jessie Hoffman, 46, is scheduled to die by nitrogen gas on Tuesday at Louisiana state penitentiary, commonly known as Angola prison. He was sentenced to death for the 1996 rape and murder of an advertising executive, Mary Elliott.

Should the execution go ahead, Louisiana would become only the second state to use nitrogen gas as a means of killing people. Lawyers for the condemned man have decried the pending procedure as cruel and unusual punishment.

They point to the four nitrogen executions that have been carried out in recent months in Alabama, in which all four prisoners displayed signs of distress on the gurney. They included Kenneth Smith, who eyewitnesses said shook violently, writhed and convulsed as he was forced to breathe pure nitrogen through a mask.

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