CHICAGO, United States (AFP) — The governor of the US state of Ohio on Thursday delayed three scheduled executions over concerns that a drug currently used in lethal injections could mimic the effects of “water-boarding,” widely considered a form of torture.

Governor Mike DeWine delayed executions scheduled as early as May, in line with a court ruling that using the controversial sedative midazolam could cause pain and suffering. The state is seeking alternatives.

“Governor DeWine is issuing today’s reprieves because it is highly unlikely that the state’s new execution protocol, which is still in the process of being developed” would be ready for use by the scheduled execution dates, his office said in a statement.

The governor’s office cited federal Judge Michael Merz’s January ruling that there was “good evidence that midazolam will cause the ‘water-boarding’ effects of pulmonary edema.”

Pulmonary edema is a medical term describing fluid build-up in the lungs. Water-boarding is an interrogation technique that simulates drowning.

The reprieves affect convicted murderers Cleveland Jackson, Kareem Jackson and Gregory Lott.

Midazolam has been the subject of numerous legal challenges, previously focused on the sedative not being strong enough to keep prisoner’s unconscious during executions.

Seven states have resorted to the drug as previously-used medications for lethal injections have become harder to obtain.

Ohio halted its use of capital punishment in 2014, following the botched midazolam execution of Dennis McGuire, during which the inmate appeared to suffer, snorting and gasping for several minutes.

Government officials since have insisted that increasing the drug’s dosage has resolved the problem.

Court rulings allowed executions in Ohio to proceed, including a federal appeals court decision in 2017 that endorsed a 50-times greater dose of midazolam.

But concerns over the drug’s use have persisted.

Last year, a convict in Tennessee opted for the electric chair, instead of a three-drug protocol including midazolam.

US Supreme Court Justice Sonya Sotomayor, in a dissent last year in another death penalty case, said using midazolam could cause “sensations of drowning, suffocating, and being burned alive from the inside out.”

“We have stopped being a civilized nation and accepted barbarism,” if such an execution procedure is allowed to remain legal, she wrote.