Nebraska ? The Nebraska Supreme Court on Wednesday stayed an execution over concerns about a new electrocution protocol in the only state that still relies solely on the electric chair for capital punishment.

Carey Dean Moore had been scheduled to die Tuesday for the 1979 murders of two Omaha cab drivers. The high court issued the stay after receiving objections this week from state Sen. Ernie Chambers of Omaha, who wants the new process reviewed before anyone is put to death.

Nebraska’s last execution was in 1997. The state decided to use a single 20-second, 2,450-volt jolt instead of several shorter ones of varying voltage after a judge rejected the old practice. But backers and foes of the new method agree that it could leave the condemned’s heart beating well after the shock.

Under the protocol announced Wednesday, officials would wait 18 minutes to determine whether an inmate is dead and administer a second jolt if the heart is still beating.

Among the concerns about the new protocol is that the condemned could be set on fire during a continuous application of electricity.