In recent decades, most states have rejected electrocution, firing squads, hanging, and gas chambers as cruel and unusual, leaving lethal injection the most popular method of execution in this country. But researchers in Florida and Virginia have found that 4 in 10 inmates executed by lethal injection may actually have been conscious during much of the procedure.

The first drug administered in most execution protocols is an anesthetic, sodium thiopental, which is often fatal by itself. The second drug is a muscle relaxant (pancuronium bromide) to paralyze muscles and lungs (but leaving the brain and nerves unaffected). Last comes potassium chloride, a toxic agent that stops the heart and is understood to be excruciatingly painful.

The study, published in The Lancet, reviewed autopsy records of executed inmates from Georgia, North Carolina, South Carolina, and Arizona (Texas, the nation's leading executioner, refused to cooperate with the study), and found that 43 percent had concentrations of anesthetic in their blood so low that they may have remained conscious to the end. The medical journal editorialized, "It would be a cruel way to die: awake, paralyzed, unable to move, to breathe, while potassium burned through your veins."

The muscle relaxant, pancuronium bromide (or Pavulon, the trade name), derived from curare and used in executions in 29 states, has become highly controversial in recent years. It has been banned in most of the country for use in euthanizing animals, meaning that in many states (Texas, Tennesseee, and South Carolina, for example) the drug is considered too cruel for killing animals but perfectly fine for killing humans. (Pavulon also appears to have become a popular murder weapon.) Writing for on the use of Pavulon in Tennessee's execution protocol, Christopher Brauchli says:

It would be easy to simply condemn Tennessee for being a state that lacks respect for life. That would be a mistake. Tennessee has a law that is known as the "Nonlivestock Animal Humane Death Act." Nonlivestock is defined to include pets, captured wildlife, exotic and domesticated animals, rabbits, chicks, ducks and potbellied pigs. Tennessee law says: "A nonlivestock animal may be tranquilized with an approved and humane substance before euthanasia is performed." The law then provides that "any substance which acts as a neuromuscular blocking agent, or any chamber which causes a change in body oxygen may not be used on any nonlivestock animal for the purpose of euthanasia."

The unfortunate thing, as far as those facing the executioner's needle in Tennessee is concerned, is that humans are excluded from the definition of "nonlivestock animals." Thus, the requirement for a humane execution that is imposed on those killing animals is not imposed on those killing humans. Tennessee is not alone in being more concerned about kind executions of nonlivestock animals than humans.