Guy who made Tennessee's electric chair is worried it will malfunction in tonight's execution

Tennessee is set to execute a death row inmate by electric chair Thursday evening – the second time the state has used that method since 1960.

Edmund Zagorski, 63, requested death by electric chair amid concerns over the lethal injection process, as it’s been botched in several recent executions. Lawyers representing Zagorski, who confessed to a double murder in 1983, are making last-minute appeals to the U.S. Supreme Court to delay his execution in light of concerns surrounding the constitutionality of the electric chair. That method hasn’t been used in the U.S. since 2013, when Virginia put a man convicted of a double murder to death.

Tennessee, like the other 29 states with the death penalty on the books, has been grappling with a shortage of traditional lethal injection drugs, because drug companies don’t want their products associated with executions. Over the last few years, in response to the shortage, states have tried to adapt by substituting new, untested drugs in the lethal injection cocktail. This has had some disastrous consequences in some cases, including agonizingly painful and long deaths of up to 23 minutes. Tennessee’s lethal injection protocol currently uses the drug midazolam, which has been linked to a number of those botched executions.

In recently filed court documents, Kelley Henry, a lawyer representing Zagorski, says that forcing him to choose between lethal injection and the electric chair is unconstitutional.

“The state of Tennessee has coerced Mr. Zagorski – with the threat of extreme chemical torture via a barbaric three-drug lethal injection protocol – to choose to die a painful and gruesome death in the electric chair,” Henry writes.

Read more: Death penalty states are looking for new ways to execute people

On one hand, with lethal injection, “the prisoner [will feel] as if he is ‘drowning, suffocating, and being burned alive from the inside out’ during a process that could last as long as 18 minutes,” Henry says. But on the other, Zagorski is facing a process that has been abandoned or declared unconstitutional across most of the rest of the country.

According to the Death Penalty Information Center, 88 percent of the nearly 1,500 people put to death since 1976 have been executed by lethal injection, and 11 percent by electrocution. The remaining 1 percent were killed by gas chamber, hanging or firing squad.

Even though 30 states still have the death penalty on the books, just eight states carried out all 23 executions in 2017.

Tennessee, Alabama, Florida, South Carolina, Kentucky, and Virginia are the only states that give death row inmates the option to die by electrocution. Arkansas, Oklahoma and Mississippi law gives the state the authority to bring back the electric chair, should other methods be ruled unconstitutional.

In recent weeks, the man who made the electric chair that Zagorski is set to be executed in told ABC News he’s concerned it will malfunction. Fred Leuchter, who is best known for being a Holocaust denier, is a self-taught engineer and manufacturer of execution equipment, from electric chairs to lethal injection machines. "What I'm worried about now is Tennessee's got an electric chair that's going to hurt someone or cause problems. And it's got my name on it," Leuchter told ABC. "I don't think it's going to be humane."