Arizona bishops are “very concerned” that the state could resume executions this fall – including the possibility of executions by gas chamber.

Documents obtained by The Guardian show that Arizona’s department of corrections spent more than $2,000 on the necessary ingredients to make hydrogen cyanide gas - the same type of gas used in the infamous Nazi concentration camp of Auschwitz.

The documents also reveal the state has “refurbished” its gas chamber for executions.

Ron Johnson, executive director of the Arizona Catholic Conference, told CNA on Monday that no matter the method of execution, “the bishops of Arizona are very concerned we might be resuming executions in Arizona as early as late September or early October after a seven year pause from litigation.”

“We’re very concerned about that, we believe the death penalty contributes to a culture of death, among other things, and our opposition remains firm,” Johnson said.

Pope Francis in 2018 ordered a revision to the Church’s catechism, calling the death penalty “inadmissible” and an “attack on the inviolability and dignity of the person.” Bishop Daniel Flores of Brownsville, the next doctrine committee chair of the U.S. bishops, has said the death penalty is part of the “throwaway culture” condemned by Pope Francis.

In a statement to CBS News, the Arizona Department of Corrections stated its intent to resume executions.

The department said it is “prepared to perform its legal obligation and commence the execution process as part of the legally imposed sentence, regardless of method selected. (The department) stands ready, with the Arizona Attorney General's Office, to carry out court orders and deliver justice to the victims' families.”

The statement noted that Arizona law permits death row inmates to choose between dying from lethal injection or gas.

"If the defendant fails to choose either lethal injection or lethal gas, the penalty of death shall be by lethal injection," the statement said.

According to the Death Penalty Information Center, the state has executed 37 people since 1976, and there are 119 people on death row.

It last executed a prisoner in 2014, a botched execution where inmate Joseph Wood died two hours after being injected with lethal drugs. An Arizona Republic reporter observed Wood wheezing hundreds of times, gulping, convulsing, and making loud snoring and sucking noises before he died.

Arizona is one of 27 states, as well as the federal government, that still permit the use of the death penalty. The Trump administration executed 13 federal death row inmates last year, after the federal government had not executed any prisoners for nearly two decades.

The state last executed a prisoner with lethal gas in 1999, according to the New York Times. Christoph Heubner, executive vice president of the International Auschwitz Committee, told the paper that for survivors of the camp, “the world will finally come apart at the seams, if in any place on this earth the use of Zyklon B in the killing of human beings is considered again.”