LINCOLN, Neb. — Nebraska state officials are preparing for their first execution in two decades and first-ever lethal injection with an untried combination of drugs that includes a powerful painkiller responsible for much of the nation's opioid epidemic and a paralyzing drug that could conceal whether something has gone wrong.
The execution planned for Aug. 14 at the Nebraska State Penitentiary in Lincoln comes with significant risks for Nebraska prison officials, who haven't carried out a death sentence since using the electric chair in 1997.
No state in modern history has resumed executions after such a long hiatus, according to the Death Penalty Information Center, a nonprofit opposed to capital punishment that tracks how states perform executions. Nebraska is also poised to become the first state to use a four-drug protocol, including three substances that have never been used in a lethal injection.
"When states start experimenting with a new drug combination, it heightens the likelihood there's going to be some kind of error," said Deborah Denno, a law professor and lethal injection expert at Fordham University in New York.
Nebraska is among a handful of states that still have capital punishment on their books but haven't carried out an execution in decades as the total number falls nationally, according to the information center.
The last executions in Colorado, Oregon and Wyoming took place in the 1990s. Kansas hasn't executed an inmate since 1965, and New Hampshire hasn't done so since 1939. Nebraska lawmakers abolished the death penalty in 2015, but voters reinstated it the following year through a ballot initiative partially financed by Republican Gov. Pete Ricketts.
Prison officials are set to execute Carey Dean Moore, who has spent 38 years on Nebraska's death row for the 1979 shooting deaths of two Omaha cab drivers. The 60-year-old Moore has stopped fighting the state's efforts to execute him.
That leaves no real options for death penalty opponents other than hoping a pharmaceutical company protests the state using one of its drugs in court. None have so far. State officials have refused to identify their supplier and appealed a judge's order to release records that would reveal their source.
Nebraska previously relied on a three-drug combination to render the inmate unconscious, induce paralysis and stop the heart. But the protocol was never used in an execution, and after years of failing to acquire one of the drugs, sodium thiopental, Nebraska prison officials changed their rules to let the state corrections director choose which chemicals to use.
The new protocol calls for an initial IV dose of diazepam, commonly known as Valium, to render the inmate unconscious; the powerful synthetic opioid fentanyl; cisatracurium besylate to induce paralysis and stop the inmate from breathing; and potassium chloride to stop the heart. After each injection, prison officials send saline through the IV to flush out any residue and ensure all the drugs have entered the inmate's system.
Diazepam, fentanyl and cisatracurium have never been used in executions before. Fentanyl, the prescription painkiller, is at the center of the nation's opioid crisis. A fentanyl overdose killed music superstar Prince in 2016.
Diazepam is a sleep aid, muscle relaxant and a medicine that helps fight anxiety and seizures. Cisatracurium is commonly used to ensure patients remain still in operating rooms and requires them to be connected to a breathing machine.
Potassium chloride is used in small doses for medical patients with low blood potassium, but in large doses it can trigger a heart attack. The combined drugs would likely take five to 10 minutes at most to work, said Dr. Peter Rice, a clinical pharmacy professor at the University of Colorado.
It's unclear how the drugs might work in combination, and no one knows whether the dosages will do the job "in a way that isn't tortuous," said Robert Dunham, executive director of the Death Penalty Information Center.
The protocol "seems to be based more on expediency and what drugs the states believe they can get their hands on at any given time," Dunham said.
A corrections department spokeswoman did not return phone messages and an email seeking comment. Nebraska's protocol requires all members of the execution team to train at least weekly before an execution.
The dosages prescribed appear large enough to work as intended, but prison officials still face potential complications given the new protocol and the state's lack of recent experience in carrying out executions, said Dr. Jonathan Groner, a lethal injection expert and surgeon who teaches at Ohio State University.
Because the person administering the drugs won't be standing next to the inmate, Groner said it will be difficult to tell whether the drugs are flowing correctly through the IV tube and into his veins instead of surrounding tissue, where they wouldn't be properly absorbed.
Groner said a long delay in administering all the drugs could also give the fentanyl time to wear off, which would expose the inmate to an intense, burning pain, possibly while paralyzed.
"When you're having surgery, you get a high-dose burst followed by a continuous infusion," Groner said. "If the other drugs aren't given in rapid succession, things could go awry pretty quickly."