Barring last-minute appeals and stays of execution, Kenneth Biros, 51, will be put to death using a massive overdose of an anaesthetic. It would be the first time that a single-drug lethal injection had been administered, in contrast to the triple-drug cocktail that has become the norm in the 37 American states that have death row prisoners.
Opponents of the death penalty and lawyers involved in the Biros case have decried the move towards the single-drug method as over-hasty.
Tim Sweeney, Biros's lawyer, said: "This truly is experimentation and a more careful look needs to be taken by the courts before this new method can be used."
Sweeney and his legal team were launching last-minute attempts to persuade the courts to postpone the execution while further thought is given to the method. They were appealing to the federal appeals court and potentially to the supreme court.
Under the new so-called protocol, Biros would be administered an overdose of the anaesthetic thiopental sodium, one of the three drugs used in the lethal injection cocktail that is the most popular current technique.
If that failed, a back-up would be used involving the injection of two other chemicals, midazolam and hydromorphone, into muscles. That back-up method, in particular, has never been tested, and the qualities of the two chemicals are unknown at high doses.
Ohio opted for the new protocol in the wake of a gruesome incident in September in which an execution was botched – the third such incident in three years in the state. Romell Broom, a rapist and murderer, spent two hours on the gurney as officials tried to find a vein that would hold an intravenous drip through which the poisons that would kill him could be introduced.
During that time, Broom tried to help his executioners find a vein, turning over on his side and rubbing his arm, and he was later seen to be in distress and weeping. A doctor was called in to help apply the drip – in contravention of ethical guidelines that say doctors should not be involved in executive killings.
After 18 attempts the execution was called off and Broom was returned to death row, where he remains.
Ohio then moved rapidly to propose the single-drug method, despite the fact that no doctors could be found who would vouch for the new technique.
Charles Wille, a state prosecutor, told Associated Press: "Somebody has to be first. This plan is consistent with a long history of states attempting to take a very difficult social responsibility and make it less difficult."
Richard Dieter, head of the Death Penalty Information Centre in Washington, said that it was only because of the extraordinary nature of executions in the US that Ohio would be permitted to test out a new method on humans. "In other countries or in any medical field there would be all kinds of restrictions about doing things to experiment on human beings. It would never be allowed."
Under the Nuremberg Code, which stemmed from Nazi medical experiments, doctors must abide by strict rules relating to human experimentation, including that any test must be voluntary and for the social good. But executions are not covered by the code.
Brian Evans, a campaigner against the death penalty with Amnesty International USA, said Ohio's proposed technique "looked like human experimentation". He pointed out it still relied on finding a vein – the problem that had given rise to the new method in the first place.
Critics have also suggested that Biros, the prisoner due to die tomorrow, has been carefully chosen to inspire as little public sympathy as possible. He was guilty of a crime that was so horrifying prosecutors called him a "poster child for the death penalty". In 1991 he stabbed and beat a 22-year-old woman, Tami Engstrom, to whom he had offered a lift in north-eastern Ohio. He then dismembered her body and buried parts around the state.
Technically, states can still chose to kill inmates through hanging, the electric chair, lethal gas and the firing squad, but lethal injection is the norm.
The US supreme court ruled last year that the three-drug cocktail was constitutional. Chief Justice John Roberts briefly referred in that judgment to the prospect of using a single anaesthetic, commenting that it "has problems of its own, and has never been tried by a single state".