Executions have been set for (top row, from left) Kenneth Williams, Jack Jones Jr., Marcel Williams, Bruce Earl Ward, and (bottom row, from left) Don Davis, Stacey Johnson, Jason McGehee and Ledell Lee.

LITTLE ROCK — After nearly a dozen years without an execution, Arkansas is racing to put eight men to death next month over a 10-day period — an unprecedented timetable made necessary because one of the three ingredients in the lethal injection will soon expire.

If carried out, the executions beginning April 17 would make Arkansas the first state to execute that many inmates in such a short time since the death penalty was reinstated by the U.S. Supreme Court in 1976.

The accelerated schedule poses a number of risks, experts say, and the state's preparations are shrouded in secrecy.

Some attorneys and anti-death penalty groups question whether the quick turnaround between executions will intensify pressure on the prison staff and cause problems, as happened in Oklahoma in 2014, when an inmate writhed and moaned on a gurney for 43 minutes after his injection, or in Arizona, where the fatal dose took nearly two hours to work.

An investigation in Oklahoma found that intravenous lines had been connected improperly, in part because of the "extra stress" from the state's scheduling of two executions on the same day.

"The stress on the prison and medical staff will be increased, and the risk of making mistakes is multiplied," said Dale Baich, an assistant federal public defender who witnessed inmate Joseph Rudolph Wood's slow death in Arizona in 2014. "This along with using a drug that has been used in numerous botched executions should make the prison officials in Arkansas very nervous."

One concern in Arkansas focuses on the expertise of the prison staff. The Department of Correction will not say how many staff members will participate or whether any had experience with executions. The department said staff members are receiving training but would not describe it.

When asked what assurances the Department of Correction can give the public about its preparations, spokesman Solomon Graves said: "We are implementing procedures consistent with all applicable state law."

All that is known about the background of those conducting the executions is that anyone administering the drugs must be a certified or licensed emergency medical technician, nurse, physician's assistant or physician with at least two years of experience.

The lack of information is part of a trend among states to keep more execution details out of public view and less vulnerable to challenges from opponents.

"As states had more and more problems in carrying out executions, their response has not been to fix the problems but to hide behind secrecy to prevent those problems from being disclosed," said Robert Dunham, executive director of the Death Penalty Information Center, an anti-death penalty group.

Correction Department Director Wendy Kelley has declined to discuss the preparations. Gov. Asa Hutchinson said he's inquired about the effect of the sequence of deaths on prison staff, but said Kelley told him "it's not any easier to string it out over four or five months."

The eight inmates are still attempting to force the state to identify the suppliers of the lethal drugs, but their confidentiality is legally protected so they will not be targeted for protests.

Jeff Rosenzweig, who represents the inmates, said the secrecy is unfair.

"The execution is being done in the name of the state of Arkansas," Rosenzweig said. "It's not supposed to be a trade secret or some sort of private function, so the people have a right to know what is being done in their names."

The executions will be conducted at the Cummins Unit, where 27 inmates have been put to death since capital punishment was reinstated. This will not be the first time more than one inmate has been executed on the same day. The state has conducted two double executions and two triple executions at Cummins.

After the inmate is strapped on a gurney, the designated medical technician will administer intravenous doses of midazolam, a powerful sedative, followed by vecuronium bromide, a paralytic, and then potassium chloride to stop the heart.

The midazolam expires at the end of April. If it fails to work properly, experts say, the inmate can remain conscious during the execution.