Calvin Alphonso Shuler, 40, is to be executed at 6 p.m. His attorneys have asked Gov. Mark Sanford for clemency, but a spokesman said Thursday that the governor's legal counsel would likely recommend against it.
Mr. Shuler was armed with a handgun and assault rifle when he ordered two guards out of an armored van that was stopped outside a Harleyville bank a decade ago. Mr. Shuler, a former co-worker of the guards, exchanged gunfire with the men before driving off in the van with James "J.B." Brooks, a third guard locked in the back of the van.
Mr. Brooks, 77, and Mr. Shuler also exchanged gunfire. Mr. Shuler was wounded in the neck before he got into another vehicle and fled.
Authorities later found Mr. Brooks' body in the van, which was abandoned along a dirt road several miles from the bank.
Mr. Shuler is scheduled to be executed by lethal injection, a method that has come under scrutiny across the nation after some botched procedures. In Ohio last month, it took 90 minutes for executioners to find a vein, and the man being put to death was allowed a bathroom break.
A Florida man executed in December twice asked "What's happening?" during his 34-minute procedure and grimaced when the chemicals finally began flowing through his system.
South Carolina prisons spokesman Josh Gelinas said in a statement Thursday that the agency "goes to great lengths to perform its duty professionally and with utmost respect for everyone involved."
Changing the way executions are performed has not been discussed in South Carolina, where death row inmates may choose between the electric chair and lethal injection, said Lisa Kimbrough, a Columbia attorney who worked on Mr. Shuler's case.
"What you typically see is that it comes up after a horribly botched execution, and I suspect that, if that happened in our state, that would certainly get people's attention," Ms. Kimbrough said.
Mr. Shuler's attorneys had argued to the South Carolina Supreme Court that lethal injection was cruel and unusual punishment, but on Wednesday the high court rejected their request to stop the execution, Ms. Kimbrough said.
"With several recent cases documenting problems with lethal injection, there's also a growing section of the legal community that thinks that is also a violation of the Eighth Amendment," Ms. Kimbrough said.
Over the past year, about a dozen states have, at some point, put executions on hold because of concerns over lethal injection procedures, said David Elliot of the National Coalition Against the Death Penalty.