By Agence France-Presse
Local media who had come to attend the execution of Alva Campbell in the state of Ohio reported that there were multiple unsuccessful attempts to find a usable vein over a period of approximately 20 minutes.
Officials were ultimately forced to cancel but said a new date would be set.
Campbell's lawyers had argued the 69-year-old was too ill to be executed. They claimed he may have lung cancer, was unable to breathe without medical assistance, and his veins were in poor condition.
The US Supreme Court on Tuesday rejected a request for a stay on those grounds.
An Ohio civil rights group strongly condemned the canceled execution, saying it was the latest of several death penalty mistakes by state officials.
"This is not justice, and this is not humane. Campbell was poked and prodded for nearly two hours," Mike Brickner of the American Civil Liberties Union in Ohio said in a statement.
"This type of state-sponsored torture is not acceptable and the state of Ohio must place a moratorium on executions immediately."
Prison officials had proceeded with the execution believing they could find a vein, and planned to prop up the prisoner on a special "wedge-shaped" pillow while lying in his gurney, to keep him breathing during the lethal injection process.
Ohio halted executions after the 2014 lethal injection of Dennis McGuire, during which the inmate appeared to snort and gasp -- leading some witnesses to speculate that he suffered.
The state resumed executions this year following an appeals court approval of a new lethal injection drug protocol.
Campbell was first convicted of murder in 1972 and served 20 years in prison before being paroled.
He landed back in court for a 1997 armed robbery, but seized the weapon of a sheriff's officer and escaped.
He then hijacked the car of a bystander, 18-year-old Charles Dials, taking him hostage before fatally shooting him twice in the head.