As Challenges to Lethal Injection Mount, Justices Set to Hear Case

But two developments changed that. The first was a 2004 Supreme Court opinion that permitted one Alabama prisoner, who had exhausted all other appeals, to file a civil rights lawsuit against the state's plan to cut into his arm to reach a vein for lethal injection.

The second was a study, published by the British medical journal the Lancet in April 2005, which argued that, because of mistakes by poorly trained personnel, many U.S. prisoners put to death by lethal injection might have been able to feel pain when lethal drugs began to flow.

Reviewing 49 inmates' autopsies, the study's authors found that 21 had concentrations of sodium pentothal in their systems low enough to be "consistent with awareness."

That means they could have felt intense burning as the potassium chloride passed through their veins -- but could make no outward sign of suffering because they were paralyzed by pancuronium bromide.

Because the American Medical Association bars physician participation in executions, states rely on paramedics or other personnel who may not know how to tell if an anesthetic is working properly, the study noted.

Another point highlighted by the litigation is that the three-drug protocol was developed almost serendipitously, initially at the suggestion of an Oklahoma state medical examiner who had little experience in anesthesiology. Other states followed without much question.

"They never consulted with any experts," said Jamie Fellner, U.S. program director for Human Rights Watch, a New York-based organization that opposes the death penalty.

State officials say that objections to lethal injection protocols are based on remote possibilities, and that their execution teams, though necessarily anonymous, are well trained.

Even death-penalty opponents concede that, when it is properly administered, the usual dose of sodium pentothal alone is sufficient to bring on not only unconsciousness but death.

Opponents say that the purpose of pancuronium bromide is "cosmetic" -- to preserve the appearance of a peaceful death. They note that it has been banned in many states for euthanasia of animals.

But without the drug, "it would take longer to die," says Joshua K. Marquis, district attorney of Clatsop County, Ore., and vice president of the National District Attorneys Association.

Lawyers began pressing a variety of lethal injection-related claims. But most inmates who had exhausted all their other appeals and were facing imminent execution were not given stays of execution by the Supreme Court.