Attorneys for four Oklahoma death row inmates are appealing to the U.S. Supreme Court to overturn a 10th Circuit Court ruling that approved the state's execution drug protocol.

Attorneys for Charles Warner, Richard Eugene Glossip, John Marion Grant and Benjamin Robert Cole have also requested stays of their scheduled executions, pending the appeal.

The documents filed Wednesday allege that the use of midazolam in a three-drug mixture to perform an execution is unacceptable because it cannot reliably produce "a deep, comalike unconsciousness."

The drugs were first used in Oklahoma in the April 29 execution of Clayton Lockett, whose lethal injection went awry after an intravenous line failed.

Warner is scheduled to die Thursday, Glossip on Jan. 29, Grant on Feb. 19, and Cole on March 5.