If all goes as planned and Scott Dozier is strapped into a gurney and given a lethal overdose in the state’s execution chamber on Wednesday night, it will mark many firsts for the state.

It will be the first death in the state’s new execution chamber in Ely State Prison, the first inmate executed in Nevada in over a decade and the first time any state has used fentanyl and two other drugs to execute an inmate condemned to death.

Spurned by pharmaceutical companies who have strongly objected to their products being used in executions, Nevada plans to use a combination of commonly available sedatives and painkillers as part of a never-before-used lethal drug combination to kill Dozier, who was convicted of two murders in the early 2000s and has given up appeals.

The stakes are high — Amherst College professor Austin Sarat estimated that lethal injections had historically the highest number of “botched” executions in the U.S. over the past 120 years, at a rate of 7.12 percent.

Nevada has never had a “botched” execution in its 12 executions since reinstating the death penalty in 1976 — the closest was a 20-minute delay in the 1998 execution of Roderick Abeyta by lethal injection, due to troubles with finding a “good vein.”

But the state’s chosen lethal drug cocktail for Dozier is thrusting Nevada square into the middle of a long-running battle over lethal injection drugs and raising some fears over what could happen if the drugs don’t work as intended.

The state plans to use the sedative midazolam, the painkiller fentanyl and a paralytic, Cisatracurium, as part of a drug cocktail that was first revealed by state prison officials last week. It’s a slightly different combination than the state’s initial planned cocktail for Dozier’s called-off November execution, but remains a combination that has never been used in any other state.

Although Dozier has been blasé about the particulars of his planned demise, death penalty critics, including the American Civil Liberties Union of Nevada, say the drug combination — especially midazolam — presents significant concern, and in the worst case could lead to an agonizing, slow death by suffocation but with no way to indicate distress because of the presence of a paralytic agent.

“I think there’s definitely a concern as to whether or not it's going to be successful,” ACLU spokeswoman Lauren Coffman said. “When different cocktails of drugs are used, and someone is killed through lethal injection, there’s no real way of knowing. Obviously if someone dies, there’s no way, we can’t ask that person was it painful or if it was torturous.”

Finding the right kind of drugs hasn’t been an issue until recently. In the 2006 execution of Daryl Mack, the last Nevada inmate to be killed by the state, the state Department of Corrections used a combination of sodium thiopental (a barbiturate than induces unconsciousness), Pavulon (pancuronium bromide, which paralyzes the diaphragm and stops breathing) and Potassium Chloride (which stops the heart) — a typical drug cocktail used in executions before 2010, according to the Death Policy Information Center.

But advocates and pharmaceutical companies have over time moved to limit the kinds of drugs states historically use to execute prisoners, mainly barbiturates, forcing state correctional departments to look at other drugs for use in lethal injections.

Enter midazolam — a common sedative drug similar to Valium commonly used in colonoscopies and other standard medical procedures but has been increasingly been used in executions.

Florida was the first state to use the sedative drug as part of an execution in 2013, and at least five other states have begun using it — Ohio, Oklahoma, Alabama, Virginia and Arkansas.

Use of the drug has been controversial. Several inmates in Alabama, Oklahoma, Arkansas and Ohio were executed using a drug cocktail including midazolam but showed signs of consciousness after the sedative was injected. Midazolam was used in the 2014 execution of Oklahoma inmate Clayton Lockett, who “writhed and grimaced on the gurney, struggled to lift his head and died of a heart attack more than 40 minutes later.”

The U.S. Supreme Court upheld use of the sedative drug in 2015, ruling in a 5-4 decision that even though midazolam does not reliably cause deep unconsciousness before the administration of other lethal drugs, its continued use by states did not violate the 8th Amendment’s prohibition on cruel and unusual punishment.

UC Berkeley law professor Megan McCracken, who specializes in lethal injection law, noted that any potential issues caused by midazolam could be masked by the paralytic drug.  

“Nevada has made last-minute changes to its execution procedure, replacing valium with midazolam, a drug that has been implicated in past botched executions,” she said in an email. “The use of midazolam in Nevada's new lethal injection procedure presents the same risks as the previous drug combination. The procedure calls for the unnecessary administration of a paralytic drug, which will serve only the cosmetic purpose of hiding any problems with the execution.”

It’s possible that the drug could not be used in the execution. Pharmaceutical company Alvogen filed a lawsuit on Tuesday seeking to block use of midazolam produced by the company during the execution, saying the state had “intentionally defrauded” the company by obtaining the drug even though it knew the company was opposed to the use of its products in executions.

A January article by Dr. Josh Bloom, the Senior Director of Chemical and Pharmaceutical Sciences at the American Council on Science and Health, downplayed fears that Nevada could see a repeat of horrific botched executions such as one in Arizona that took two hours to kill inmate Joseph Rudolph Wood, which a reporter described as “death by apnea.”

Although Arizona used midazolam in that execution, Bloom wrote that the state used a different opioid — hydromorphone —  that Nevada’s planned use of fentanyl, a synthetic opioid that is “much stronger” and “works much faster.”

“There will be no two-hour deaths if people are executed using Valium and fentanyl,” he wrote. “Death will come quickly and not be experienced if sufficient Valium is used.”

Bloom also wrote that the use of Cisatracurium as a paralytic agent wasn’t a concern, since “dead people don’t need to be paralyzed.”

If the execution goes forward, Nevada will become the first state to execute an inmate via fentanyl overdose. The only other state that plans to use the opioid, Nebraska, is scheduled to execute an inmate in August using a four-drug cocktail including fentanyl.

Dozier himself has been clear about his desire to die, and has downplayed concerns with the drug combination.

“I went into this recognizing I wouldn’t know those things,” he said last August. “Listen, if they tell me there’s a good chance it’s going to be a real miserable experience for you for those two hours before you expire, I’m still going to do it.”

In an interview with the Reno Gazette-Journal last week, Dozier said he wasn’t concerned about the paralytic and was satisfied by the high amounts of drugs that will be pumped into his bloodstream on Wednesday night.

“I don’t even really care,” he told the newspaper. “I mean, ideally, I don’t want to be on their (expletive) table suffering and not being able to breathe and be aware of it. The fact is they’re not going to allow me off that table if I’m not dead. It’s going to get achieved.”