Attorneys for a 66-year-old Texas death row inmate say his health problems make him unsuitable for lethal injection scheduled for this week so they’re proposing he be rolled in his wheelchair in front of a firing squad or be administered nitrogen gas to cut off oxygen to his brain until he stops breathing.

If the state doesn’t accept one of their alternatives, lawyers for confessed multiple killer and rapist Danny Paul Bible contend his lethal injection, set for Wednesday evening, should be halted because it would be unconstitutionally cruel and present a “substantial risk” of being botched due to his “unique constellation of medical issues.”

The 5th U.S. Circuit Court of Appeals refused the appeal Tuesday, affirming a decision from a federal judge in Houston last week.

Bible’s attorneys said they would take the case to the U.S. Supreme Court.

State attorneys argued the civil rights lawsuit was a “meritless tactic” to delay his “well-deserved execution.” Neither firing squad nor nitrogen gas are legal execution methods in Texas and the state Legislature isn’t scheduled to meet again until next year. A handful of death penalty states allow nitrogen hypoxia, although the method hasn’t been used. Three Utah inmates have been executed by firing squad, the most recent in 2010. Utah now allows that method if drugs for execution are unavailable.

No one is disputing Bible’s guilt for a Houston slaying nearly 40 years ago that went unsolved for two decades before a jury convicted him of it and sent him to Texas death row.

Bible, a drifter with a record of violence in several states, would be the seventh convicted killer executed this year in Texas, equaling the state’s total for all of 2017. He’d be nation’s the 12th prisoner executed this year.

Bible’s lawyers sought a reprieve, a restraining order and an injunction to block his execution, arguing Bible had no suitable sites on his body for IVs to deliver a lethal dose of the sedative pentobarbital and that severe tremors accompanying his Parkinson’s disease would complicate insertion of IV needles. They also warned of a problematic execution like ones in recent years in Ohio and Alabama.