Story highlights South Carolina officials push for shield law that would keep drug suppliers confidential

Drugs used for lethal injection harder to get as manufacturers don't want their products used in executions

(CNN) South Carolina lacks the drugs it needs to execute a death row inmate, who was scheduled to die on December 1.

The inmate, Bobby Wayne Stone had been convicted of killing a police officer, Sgt. Charlie Kubala in 1997. As the execution looked unlikely to happen next week, Stone was granted a stay of execution by a US district judge on Tuesday.

South Carolina lacks three drugs: pentobarbital, pancuronium bromide and potassium chloride. The first (pentobarbital) puts the prisoner to sleep, the second (pancuronium bromide) brings on paralysis, and the final agent (potassium chloride) stops the heart.

"All of those drugs are expired or we're unable to get them and we've returned them to the manufacturer because they have been expired," said Bryan Stirling, director of the states Department of Corrections in a Monday press briefing.

Drugs used for lethal injection have become harder to get as manufacturers don't want their products used in executions.