Death row inmate Kenneth Eugene Smith responded Friday to Alabama’s request to set a date for his execution by nitrogen hypoxia, a method not used by any state.

In the response filed with the Alabama Supreme Court, attorney Andrew Johnson, gave three reasons opposing the motion by Attorney General Steve Marshall asking the court to set Smith’s execution date.

First, Johnson wrote that the request was premature because, contrary to the state’s request, Smith has not exhausted his appeals. Johnson wrote that Smith has an appeal pending with the Alabama Court of Criminal Appeals.

Second, Johnson objected to the state’s move to make Smith the first inmate scheduled for execution by nitrogen hypoxia.

“The State seeks to make Mr. Smith the test subject for the first ever attempted execution by an untested and only recently released protocol for executing condemned people by the novel method of nitrogen hypoxia,” Johnson wrote.

The Alabama Legislature approved nitrogen hypoxia executions in 2018 as an alternative to lethal injection. The state gave death row inmates a chance to opt for lethal injection that year. About 50 inmates did so, but Smith did not. Johnson wrote that there are death row inmates who have exhausted their appeals who opted for nitrogen hypoxia.

Third, although Alabama released a protocol for nitrogen hypoxia in a court document, Smith said it was “so heavily redacted that it is unintelligible in places.”

“It is critical that Mr. Smith be afforded an opportunity to assess fully whether the State’s proposed procedures for executing him comply with constitutional requirements because neither ADOC (Alabama Department of Corrections) or any other state or the federal government has executed anyone by nitrogen hypoxia.”

Johnson said Smith has requested an unredacted protocol but has not received it.

Smith was twice convicted by juries for the murder-for-hire of Elizabeth Dorlene Sennett in her home in Colbert County in 1988. Sennett was a pastor’s wife who was beaten and stabbed. Smith confessed to his role in the crime. Smith has been on death row since 1996.

Alabama tried to execute Smith by lethal injection in November 2022 but stopped the procedure because workers were unable to start an intravenous connection before the execution warrant expired at midnight.

Alabama also had to call off the execution of Allen Eugene Miller in September 2022 because the execution team could not tap his veins.

In a federal lawsuit, Smith sought to block a second attempt to execute him by lethal injection, alleging it would subject him to cruel and unusual punishment. Smith claimed he was strapped to a gurney and poked with needles for several hours during the unsuccessful attempt to tap his veins.

State officials have told the federal court they will not try again to execute Smith by lethal injection. Instead, Attorney General Marshall asked the Alabama Supreme Court to set a date to execute Smith by nitrogen hypoxia. The state made that request on August 25. Friday was the deadline for Smith to respond.

The state has noted that Smith, as part of his lawsuit to avoid lethal injection, supported his argument by saying the state had an alternative method available, nitrogen hypoxia. Smith claims that does not waive his right to challenge nitrogen hypoxia.

Alabama’s redacted protocol for nitrogen hypoxia says the condemned inmate will be on a gurney and have a mask placed on his face. It says the nitrogen gas will be administered for 15 minutes or for five minutes following a flatline indication on the EKG, whichever is longer.

Read more: Former sheriff recalls woman’s ‘horrific’ murder-for-hire by pastor as Alabama prepares execution