With multiple petitions pending before the Nevada Supreme Court, it is becoming increasingly unlikely that the Clark County district attorney’s office will be able to obtain an order of execution for death row inmate Zane Floyd by Feb. 28, the day a key drug in the state’s lethal injection drug protocol will expire.

On Thursday, Clark County Deputy District Attorney Alex Chen told U.S. District Court Judge Richard Boulware — who previously stayed Floyd’s execution in June last year — that his office believes it is “theoretically possible but highly unlikely” that petitions pending in state court will be resolved by Feb. 13, the latest possible day to obtain a warrant and order for a Feb. 28 execution date.

Under Nevada law, the Clark County district attorney’s office must obtain a warrant and order for the execution at least 15 days before Monday of the week of the execution.

However, Chen said his office would not seek a warrant until the Supreme Court provides clarity on the pending petitions. Chen noted that those petitions, filed by Floyd’s lawyers, involve challenges to which judge can issue an execution order and where the execution can take place. Though Nevada statute states, “the execution must take place at the state prison,” the execution chamber for Floyd is at Ely State Prison; lawyers argue that the law limits the practice to Nevada State Prison, which closed in 2012 and is located in Carson City.

“Our position still is, however, that Mr. Floyd has exhausted all of his appeals and that this is an improper appeal,” Chen said.

Floyd, 46, was convicted and sentenced to death more than 20 years ago after killing four people and injuring a fifth person inside a Las Vegas grocery store in 1999.

The district attorney’s office has only a matter of days to start processing Floyd’s execution protocols. The state’s proposed lethal injection protocol involves the use of the drug ketamine, but the state’s supply of the drug is set to expire on Feb. 28.

Without ketamine, the Department of Corrections could face significant problems moving forward with an execution, as lawyers for the state have said the department is unable to obtain more of the drug through its supplier Cardinal Health. The state could also face issues if it tries to use a different combination of lethal injection drugs, as most major drug manufacturers have publicly opposed the use of their products in executions and typically block prisons from purchasing certain drugs.

On Thursday, Randall Gilmer, the chief deputy attorney general who represents the corrections department, said the state does not believe it can obtain more ketamine and that there have not been discussions about creating a new execution protocol.

The state also faces potential issues related to the staff set to be involved in the execution. Earlier this week, The Associated Press reported that several medical personnel enlisted by the state to take part in the execution withdrew from consideration, noting that they do not want to be publicly identified. The American Medical Association has said that doctor participation in executions is unethical and violates the Hippocratic Oath.

Boulware had previously requested information about the doctors’ backgrounds and training to ensure they are qualified to carry out the execution. William Gittere, deputy director of operations for the corrections department, said in a court filing that ​​providing certain information, such as specialty or education, would be easily identifiable in the small community of Ely, Nevada.

But on Thursday, Boulware sought to clear up the confusion by telling state officials that he did not wish to publicly reveal their identities in any way. Boulware said he needed information from the department about the qualifications of the medical personnel to handle specific complications that could arise during the execution, such as issues with the IV administration or the drugs being used.

Boulware has also not yet ruled on arguments regarding the constitutionality of the lethal injection protocol. In hearings held in November and December, experts called by Floyd’s counsel highlighted potential complications of the protocol, including the possibility that it would cause suffering, while experts called by the state argued that the plan would be effective and painless.

The next hearing in the case is set for Feb. 14.