The move is almost certain to spur more litigation over the state's already-embattled death penalty, in limbo for nearly a year in the aftermath of a U.S. Supreme Court decision last January that struck down as unconstitutional Florida's capital sentencing system because it gave too much power to judges, instead of juries.
The Department of Corrections posted the revised three-drug lethal injection protocol on its website Thursday, a day after Secretary Julie Jones signed the new procedure.
The new triple-drug cocktail is the only one of its kind among the states that rely on similar procedures and incorporates a sedative never before used in executions, along with a killing agent used only once —- when Oklahoma executioners used it by accident.
"It's certainly troubling that the state of Florida is continuing to use experimental protocols in lethal injection," said Maria DeLiberato, a lawyer who represents Death Row prisoners, including inmate Dane Abdool.
Abdool is one of five Death Row inmates who are plaintiffs in a federal lawsuit challenging Florida's lethal-injection protocol.
"We'll have to review the protocol, discuss with appropriate experts and make a determination regarding any litigation," DeLiberato said in a telephone interview Thursday.
The News Service of Florida first reported in December that the corrections agency may be considering a new drug protocol, based on records related to a lawsuit filed by Arizona Death Row inmates. The records revealed that Florida has run out of the sedative midazolam hydrochloride, will soon run out of potassium chloride —- the final drug in the triple-drug lethal injection cocktail —- and spent $12,000 last year stockpiling three new drugs.
Department of Corrections spokeswoman Michelle Glady said in an interview Thursday the agency did not know whether the protocol has ever been used elsewhere.
States have been scrambling to obtain lethal injection drugs after manufacturers have refused to sell the substances to corrections agencies for execution purposes.
In its new protocol, Florida is substituting etomidate for midazolam as the critical first drug, used to sedate prisoners before injecting them with a paralytic and then a drug used to stop prisoners' hearts.
Midazolam, still in use by some states, is the focus of the Arizona lawsuit, filed after convicted killer Rudolph Wood took two hours to die in 2014. Arizona corrections officials have tried to get the lawsuit dismissed as moot because they contend they have run out of the drug and it is no longer available. At least four other states claim they have supplies of midazolam.
Concerns about midazolam also prompted the Florida Supreme Court last year to halt the execution of Jerry William Correll, pending the outcome of a lawsuit filed by Oklahoma prisoners over the drug's use. In June 2015, a sharply divided U.S. Supreme Court rejected the challenge in the landmark case, known as Glossip v. Gross.
Etomidate, also known by its brand name "Amidate," has never been used before as part of the three-drug execution procedure in the U.S., according to Megan McCracken, a lawyer with the Death Penalty Clinic at the University of California, Berkeley Law School.
The constitutionality of any state's three-drug execution procedure hinges on the first of the drugs used in the process, McCracken said in a telephone interview. Ensuring that prisoners are properly sedated is critical to guaranteeing that the lethal-injection procedure does not violate Eighth Amendment prohibitions on cruel and unusual punishments, she said.
The new protocol also replaces potassium chloride, the drug used to make prisoners' hearts stop beating, with potassium acetate. According to records obtained by the News Service, the state has a small supply of potassium chloride that will expire next month and began purchasing potassium acetate in March.
Potassium acetate has only been used once before, according to death penalty experts.
Last year, Oklahoma corrections officials admitted they mistakenly used potassium acetate in the execution of Charles Warner, although the state's protocol requires the use of potassium chloride.
In her letter to Gov. Rick Scott in which she certifies the new protocol, Jones wrote that the new procedure "will not involve unnecessary lingering or wanton infliction of pain and suffering."
But McCracken said it is unknown what studies or data —- if any —- the state is relying on to support its new protocol.
"What we see now is a mistake and an accident from an execution in Oklahoma codified as the new execution procedure in Florida," McCracken said. "The novel aspect of the drug formula and the experimental nature of the protocol is extraordinarily concerning."
The state's death penalty has been in flux since the January 2016 U.S. Supreme Court decision, in a case known as Hurst v. Florida, and a series of subsequent court rulings on the issue.
Shortly after the January ruling, the Florida Supreme Court put on hold two executions ordered by Gov. Rick Scott.
The court late last month, however, lifted a stay of execution in the case of Mark James Asay.
But the court's ruling in Asay's case may not mean that lethal injections will again be underway anytime soon, especially given the new protocol.
Corrections officials expect litigation in response to the new drugs, Glady said.
"That's very typical," she said.
In the midst of a major upheaval involving Florida's death-penalty laws, state corrections officials have adopted a new lethal-injection procedure that includes a drug never before used for executions and another used only by accident.