BATON ROUGE, La. (AP) — Louisiana’s first execution using nitrogen gas is set to move forward as planned next week after a federal appeals court on Friday overturned a preliminary injunction granted by a lower judge.

With a March 18 date hastily nearing, attorneys for Jessie Hoffman Jr., the man on death row, told The Associated Press that they plan on immediately taking the legal matter to the U.S. Supreme Court in the hopes of halting the execution.

If the death penalty is carried out, Hoffman., who was convicted of the 1996 murder of Mary Elliott in New Orleans, would be Louisiana’s first execution in 15 years.

Under the state’s new procedure, Hoffman will be strapped to a gurney and forced to breathe pure nitrogen gas through a full-face respirator mask. The protocol is nearly identical to that of Alabama, the first state to use nitrogen hypoxia as a method of execution and has carried out four such executions.

Hoffman’s attorneys say that the new execution method is a violation of the Constitution, describing it as cruel and unusual punishment. During a hearing last week, multiple medical experts testified that they believe the method to be torturous, with one expert comparing the method to causing the same sensation and emotional terror as drowning.

Hoffman’s attorneys pointed to nitrogen hypoxia executions in Alabama, where inmates appeared to shake and gasp to varying degrees during their executions, according to media witnesses, including The Associated Press. Alabama officials have said the shaking and gasping are involuntary movements associated with oxygen deprivation.

Attorneys for Louisiana remain adamant that nitrogen hypoxia is seemingly painless.

Hoffman’s attorneys also argued that the method infringes on Hoffman’s freedom to practice his religion, specifically Buddhist breathwork and meditation exercises.

“It is particularly cruel that this nitrogen gassing method will prevent Jessie from practicing his Buddhist breathing, a core tenet of the Buddhist faith, at the crucial moment of transition between life and death,” Hoffman’s attorney Cecelia Kappel said in a statement Friday.

Following last week’s hearing, U.S. District Judge Shelly Dick issued a preliminary injunction stopping the state from immediately moving forward with the execution. In her ruling, Dick said the court is tasked with answering the ultimate question of whether or not the execution method of nitrogen hypoxia is a cruel and unusual punishment, which would be a violation of the Eighth Amendment.

Dick ruled that it was in the public’s interest to halt the execution until the matter can “be resolved at a trial on the merits.” She went on to say that it would not be a matter of whether Hoffman would be executed, but rather how.

During the hearing, Hoffman requested that he be put to death using a “humane” method — specifically asking for death by a firing squad or a drug cocktail typically used for physician-assisted death.

The only approved execution methods for carrying out capital punishment in Louisiana law are nitrogen hypoxia, lethal injection and electrocution.

Under the decision from the 5th U.S. Circuit Court of Appeals in New Orleans on Friday, the execution will move forward as originally scheduled. Louisiana would be the second state to use nitrogen hypoxia.

Kappel and a spokesperson for the attorney general confirmed the appeals court’s decision to the AP on Friday night.

“This is justice for Mary ‘Molly’ Elliot, her friends, her family and for Louisiana,” Attorney General Liz Murrill said.

Kappel denounced the decision, saying that the “new execution method is likely to cause Jessie to suffer psychological terror and a torturous death.”

Alabama first used the method of nitrogen hypoxia to put Kenneth Eugene Smith to death last year. That execution marked the first time a new method had been used in the U.S. since lethal injection was introduced in 1982.

Nationally, over recent decades, the number of executions has declined sharply amid legal battles, a shortage of lethal injection drugs and waning public support for capital punishment. That has led a majority of states to either abolish or pause carrying out the death penalty.

Last year, Louisiana lawmakers expanded the state’s approved methods to carry out the death penalty to include nitrogen hypoxia, sparking a renewed push to resume executions in the state.

Republican officials, including Gov. Jeff Landry and Murrill, say the state is long overdue in delivering justice that has been promised to victims’ families. Murrill told The Associated Press last month that she expects at least four people will be executed this year. There are 56 people on Louisiana’s death row.