U.S. Supreme Court opinion
The drug was used in executions in Arizona, Ohio and Oklahoma in 2014 that took longer than usual and raised concerns that the sedative did not perform its intended task of putting inmates into a coma-like sleep.
In the Oklahoma case, Clayton Lockett took over 40 minutes to die.
Investigations showed Lockett's vein burst during the execution process. The drugs went into his tissue, not his vein, and he died of a massive heart attack, according to the follow-up investigations.
4/28/2015 Related Story: Supreme Court To Rule If Oklahoma Execution Drug Is Constitutional
Oklahoma Department of Corrections spokeswoman Terri Watkins confirmed Monday that the state has access to midazolam and the other drugs needed to carry out the executions.
Oklahoma Attorney General Scott Pruitt's office is expected to notify the Oklahoma Court of Criminal Appeals that three inmates have exhausted their appeals. The court will then set execution dates for Richard Eugene Glossip, John Marion Grant and Benjamin Robert Cole.
Statement from Oklahoma Attorney General Scott Pruitt:
“The state of Oklahoma is vested with the authority to carry out the sentence of death handed out by juries for the most heinous of crimes. State officials act deliberately and thoughtfully in carrying out this responsibility. This marks the eighth time a court has reviewed and upheld as constitutional the lethal injection protocol used by Oklahoma. The Court's ruling preserves the ability of the Department of Corrections to proceed with carrying out the punishment of death. The state appreciates the justices' thoughtful consideration of these important issues. I also want to thank Solicitor General Patrick Wyrick and the entire trial team at the Attorney General's Office for their outstanding legal work in arguing and winning this case before the highest court in the land.”
Death row inmates and their attorneys argued the drug cocktail is experimental.
The state revised execution protocols after Lockett's death in April 2014. New protocols called for expanded training for personnel administering drugs and to increase the drug dosages in the cocktail.
The state has also made enacted a law that nitrogen hypoxia can be used for executions.
The Associated Press contributed to this report.