The bishops of Tennessee issued a letter to the state's governor Friday, encouraging him to halt upcoming executions expected to use a controversial three-drug lethal injection. 

"It is within your power to establish your legacy as a governor of Tennessee who did not preside over an execution on your watch," the bishops wrote July 13 to Governor Bill Haslam. "We urge you to use your authority as governor to put an end to the fast-track executions planned for later this year."

The bishops emphasized the value of all human life, even that of those convicted of horrendous crimes, offering themselves a resource to the governor for any questions regarding Catholic teaching on the subject.

The letter was signed by Bishop Mark Spalding of Nashville, Bishop Richard Stika of Knoxville, and Bishop Martin Holley of Memphis. The request came ahead of the pending execution of Billy Irick, who is scheduled to die August 9 by lethal injection.

Irick was convicted of the rape and murder of Paula Dyer, a seven-year-old girl. His execution would be the first in Tennessee since 2009, and the first to use the three-drug combination of midazolam, vecuronium bromide, and potassium chloride (or, for legal reasons, slight variations of those drugs).

The bishops' letter follows a July 9 lawsuit contending that the use of the three-drug cocktail constitutes "cruel and unusual punishment." Tennessee currently has 62 men and one woman on death row, more than 30 of whom are party to the lawsuit. 

Tennessee transitioned to the three-drug cocktail in January when pentobarbital, the previous drug used in lethal injection, was no longer available. In a request to the Tennessee Supreme Court, state Attorney General Herbert Slater unsuccessfully sought to fast-track eight executions before some of the drugs expired on June 1. 

Concerns have been expressed about the new drugs' effectiveness. In an email to state officials, a consultant charged with acquiring the new drugs highlighted midazolam's weak analgesic effects, according to the Nashville Scene

"Here is my concern with Midazolam," the consultant wrote in an email last September. "Being a benzodiazepine, it does not elicit strong analgesic effects. The subjects may be able to feel pain from the administration of the second and third drugs. Potassium chloride, especially."

Midazolam has been cited as a cause in previous botched executions. In 2014, Clayton Lockett was administered the three drugs and declared unconscious in Oklahoma. He was then found to be able to speak and attempted to raise himself off his stretcher. Lockett died of a heart attack 43 minutes into the execution. 

Currently, state supplies of two of the three drugs have now expired, leading Tennessee to seek compounded drugs, custom-made by pharmacies, as substitutes.

However, experts have warned against the dangers of compounded drugs, adding to previous concerns about midazolam. In June, lawyers for death row inmates in Tennessee pointed to the execution of Ricky Gray in Virginia last year. 

"Blood found on his lips indicated that blood entered Gray's lungs while he was still breathing," wrote the attorneys, noting the compounded drugs used in the execution may have caused a similar experience to "drowning or a sarin gas attack."

Speaking beyond specific concerns with lethal injections, the Tennessee bishops wrote that capital punishment contributes to the erosion the dignity of the human person. The Tennesee bishops' efforts echo Saint John Paul II's stance against capital punishment, which in 1999 helped persuade Missuori Governor Mel Carnahan to commute the sentence of Darrell Mease to life in prison. 

"It is simply not necessary as the only means to protect society while still providing a just punishment for those who break civil laws," the bishops wrote. "Rather than serving as a path to justice, the death penalty contributes to the growing disrespect for human life."