Attorneys argued that nitrogen gas executions are "cruel and unusual punishment," noting that veterinarians have banned them for euthanizing animals.

Nitrogen gas is banned in Louisiana to euthanize dogs. The state plans to use it to kill a death row inmate next month - ‘This is a state that hasn't executed anybody in 15 years, and suddenly there’s this rush to kill,

Christopher Sepulvado, 81, died Saturday at the Louisiana State Penitentiary in Angola, Louisiana, "from natural causes as a result of complications arising from his pre-existing medical conditions," according to the Louisiana Department of Public Safety and Corrections.

Jessie Hoffman, who is scheduled to be executed by nitrogen gas on March 18, has filed a new federal lawsuit challenging Louisiana's execution protocol, claiming it may violate the Eighth Amendment.