The US Court of Appeals for the Eighth Circuit Tuesday held that Arkansas’ three-drug execution protocol does not violate the Eighth Amendment’s protection against cruel and unusual punishment. The case, Stacey Johnson v. Asa Hutchinson, was initially brought by death-row prisoners seeking to avoid the execution protocol in Arkansas. Though Arkansas’ supply of the three drugs has expired, the ruling means that the death-row prisoners still could face execution.

The court affirmed an earlier district court ruling which also found the death-row prisoners failed to establish that the three-drug execution protocol violated the Eighth Amendment. Death-row prisoners first brought the case in 2017 when Arkansas Governor Asa Hutchinson scheduled their execution ahead of when the state’s supply of one of the drugs was set to expire. Four of the scheduled executions occurred, but courts halted the other four. At the time, the prisoners asked the court to find the three-drug execution protocol in violation of the Eighth Amendment and to stay their executions.

Following trial, the district judge ruled that the death-row prisoners failed to prove that the three-drug execution protocol created a substantial risk of severe pain. The judge also noted that the death-row prisoners failed to present a feasible alternative to reduce the risk of severe pain they alleged was presented by the three-drug execution protocol.

The three-drug execution protocol used by Arkansas relies on midazolam, vecuronium bromide and potassium chloride. Midazolam is meant to sedate the death-row prisoner. Vecuronium bromide then stops the lungs. That is then followed by potassium chloride, which stops the heart.

At issue before the appeals court was whether the district court erred in finding that the three-drug execution protocol presents an unsubstantial risk of severe pain. At the heart of the death-row prisoners’ argument was the so-called “ceiling effect” presented by midazolam. The prisoners argued that while the drug effectively sedates the death-row prisoner, they are still aware of the pain that comes with the issuance of the second and third lethal drugs. Both the state and the prisoners presented competing scientific evidence.

Ultimately the court found “With no scientific consensus and a paucity of reliable scientific evidence concerning the effect of large doses of midazolam on humans, the district court did not clearly err in finding that the prisoners failed to demonstrate that the Arkansas execution protocol is sure or very likely to cause severe pain.”

Arkansas has not executed any death-row prisoners since the start of the case in 2017. Arkansas’ supply of the three drugs used in the execution protocol has since expired and has not been replaced.