BY KIM CHANDLER

MONTGOMERY, Ala. (AP) – Lawyers for the first inmate scheduled to be put to death with nitrogen gas argued in Monday court filings that Alabama is seeking to make him the “test case” for an experimental execution method and asked a federal judge to the block the January execution. Attorneys for Kenneth Eugene Smith, 58, filed an amended lawsuit challenging the proposed new execution method as a potential violation of the Constitution’s ban on cruel and unusual punishment. They asked a federal judge to issue a preliminary injunction to block the execution from going forward next year. Alabama Gov. Kay Ivey this month set a Jan. 25 execution date for Smith using nitrogen hypoxia, an execution method that is authorized in Alabama, Mississippi and Oklahoma but that has never been used to put an inmate to death. The Alabama Attorney General Steve Marshall’s office did not have an immediate comment on the lawsuit, a spokeswoman said Tuesday. The multi-pronged lawsuit asked a federal judge to halt the nitrogen execution, or at least delay it until Smith’s lawyers obtain more information. The proposed execution method would use a fitting mask to replace breathable air with nitrogen, causing the inmate to die from lack of oxygen. Nitrogen makes up 78% of the air inhaled by humans and is harmless when inhaled with proper levels oxygen. “There is sparse research on how long a human must be exposed to 100% pure nitrogen to cause death, what happens if a human is exposed to less than 100% pure nitrogen for a prolonged period of time, or on the pain or sensations that a human exposed to nitrogen might experience,” his attorneys wrote in the amended lawsuit filed Monday. They noted in the filing that the American Veterinary Medical Association wrote in 2020 euthanasia guidelines that nitrogen hypoxia is an acceptable method of euthanasia for pigs but not other mammals because it could create an “anoxic environment that is distressing for some species.” Smith was one of two men convicted in the 1988 murder-for-hire slaying of Elizabeth Sennett in north-western Alabama. The Alabama Department of Corrections tried to execute Smith by lethal injection last year but called off the execution when the execution team could not get the required two intravenous lines connected to Smith. Smith’s attorneys also argued Alabama violated his due process rights by scheduling the execution when he had ongoing appeals – arguing it would be unconstitutional for the state to make a second attempt to execute him after the failed 2022 lethal injection – and that the gas mask over his face would interfere with his right to make a final statement or audibly pray before he is put to death. According to the protocol filed by the state, the inmate would be escorted into the execution chamber, now used for lethal injections, placed on the gurney and have a mask fitted over their face. The warden would then read the death warrant and give the inmate a chance to give a final statement up to two minutes long. Execution team members would then make a final inspection of the mask. The warden, from another room, would then “activate the nitrogen hypoxia system.” The nitrogen gas would be administered for at least 15 minutes or “five minutes following a flat line indication on the EKG, whichever is longer,” according to the document. Smith filed litigation seeking more information about the aborted execution attempt, as he sought to prevent a second lethal injection. The state in August began seeking a court date for Smith using nitrogen hypoxia as the execution method. Smith’s attorneys argued said the state proposed the new method “on the eve of discovery deadlines” in the lethal injection litigation. Ivey and Marshall in earlier statements and court filings have noted that Smith, when fighting lethal injection, suggested nitrogen – a method that the state at that time had not finalized – as an alternative. Court rulings have required inmates objected to a state’s execution method to propose an alternative method. His attorneys argued that does not mean he agreed to the nitrogen procedures proposed by the state. Prosecutors said Smith was one of two men who were each paid $1,000 to kill Elizabeth Sennett on behalf of her husband, who was deeply in debt and wanted to collect on insurance. Her husband later killed himself. John Forrest Parker, the other man convicted in the slaying, was executed in 2010. Smith’s initial conviction and death sentence was overturned on appeal. He was retried and convicted again in 1996, but the jury this time recommended a life sentence by a vote of 11-1. A judge overrode the recommendation and sentenced Smith to death. In 2017, Alabama became the last state to abolish the practice of letting judges override a jury’s sentencing recommendation in death penalty cases, but the change was not retroactive.