MONTGOMERY, Ala. — A federal appeals court on Tuesday declined to halt Alabama's first scheduled execution in more than two years.

Christopher Eugene Brooks is scheduled to be put to death Thursday for the 1992 rape and murder of Jo Deann Campbell.

The 11th U.S. Circuit Court of Appeals denied an emergency stay sought by Brooks. Attorneys for Brooks argued his execution should be put on hold until a lawsuit challenging Alabama's lethal injection method goes to trial this spring.

The court ruled that Brooks, who joined the lawsuit two months ago, had an "unnecessary and unjustifiable delay in challenging Alabama's lethal injection."

The judges also said Brooks failed to meet his requirement to suggest an alternative execution method, "that pose a substantially lower risk of severe pain relative to Alabama's current lethal injection protocol."

Assistant Federal Defender John Palombi said he will file an emergency petition asking the U.S. Supreme Court to halt the execution.

The execution will be the Alabama's first in more than two years because of drug shortages and litigation. It will also be the first with a new lethal injection drug combination that begins with the sedative midazolam. Brooks and other inmates in the lawsuit argued there are questions about the drug's effectiveness as an anesthetic and that they will feel the effects of the next two drugs that stop their lungs and heart.

Palombi said Tuesday that Brooks should be able to "put on evidence showing that a three-drug protocol involving midazolam will leave him aware but unable to communicate while he is tortured to death with the second and third drugs."

Florida and Oklahoma have used midazolam, as Alabama plans to do, in the first of a three-drug protocol, according to the Death Penalty Information Center.

A divided U.S. Supreme Court in July ruled against Oklahoma inmates who sought to block the use of midazolam.

However, the Supreme Court ruling did not halt the Alabama litigation as attorneys for inmates argued the ruling did not settle the issue of midazolam and that Alabama's protocol had not been fully reviewed by a court.

Brooks will also be filing a separate petition to the U.S. Supreme Court asking for a stay after the high court ruled Florida's death penalty sentencing scheme, which is similar to Alabama's, is unconstitutional.

Justices last week said Florida's system for sentencing people to death is unconstitutional because it gives too much power to judges to decide capital sentences.

Palombi said Alabama's system is nearly identical to Florida's in that the trial judge weighs aggravating and mitigating circumstances, independently from the jury's advisory sentencing verdict.

A judge sentenced Brooks to death after a jury recommended a death sentence by an 11-1 vote.

Alabama Attorney General Luther Strange's office contends the Florida decision has no impact on Alabama because the jury must already unanimously find an aggravating factor at either the guilt or sentencing phase — such as when the murder was committed during a robbery, a rape or a kidnapping.

The Alabama Supreme Court on Tuesday denied Brooks' request for a stay in light of the Florida decision.