SAN FRANCISCO – A federal judge on Tuesday blocked what would have been California's first execution in nearly five years, giving a death row inmate two days away from receiving a lethal injection a reprieve that could last months.

U.S. District Judge Jeremy Fogel canceled Albert Greenwood Brown's execution after the 9th U.S. Circuit Court of Appeals ordered him to apply different legal standards than the ones he used last week when he cleared the way for Brown to be put to death.

Fogel said he halted the execution scheduled for 9 p.m. Thursday because he didn't have enough time "to render a reasoned decision and permit adequate appellate review.

The judge said lawyers for Brown had "raised substantial questions of fact as to whether at least some of the deficiencies" in California's lethal injection process that prompted Fogel to halt California executions in 2006 remained.

Brown, who was sentenced to death for abducting, raping and killing a 15-year-old Riverside County girl in 1980, alleged that the state's new lethal injection protocols did little to improve upon the old methods, which the judge had previously found to be deeply flawed.

Judge Fogel got it right this time. We need to take the time to consider the serious issues at stake here," said Natasha Minsker, death penalty policy director for the ACLU of Northern California. "This whole process has demonstrated once again that California's death penalty is dysfunctional and should be replaced with life without the possibility of parole.

California's attorney general still can appeal Fogel's latest decision. But if the decision is not reversed by Friday, the state will be unable to execute Brown — or any other death row inmate — for several months because the state's entire supply of sodium thiopental expires Friday. The chemical is used to sedate inmates before they are fatally injected with two other drugs.

The drug issue was spotlighted late Monday, when the 9th Circuit ordered Fogel to reconsider Brown's execution.

After a four-year moratorium on executions in California, multiple proceedings in federal court, a state administrative law proceeding, and state court appeals, it is incredible to think that the deliberative process might be driven by the expiration date of the execution drug," the appeals court said.

The appeals court said Fogel needed to take more time than he did to assess the state's new lethal injection procedures, which were adopted Aug. 29.

Fogel then gave attorneys just six hours to file legal arguments addressing whether the procedures avoided imposing cruel and unusual punishment.

In his response, David Senior, one of Brown's attorneys, attacked the narrow window of opportunity for the execution as having a "Cinderella quality.

Senior told Fogel the "fiasco" was created when the attorney general's office sought to execute someone so soon after the new lethal injection regulations were adopted.

It appears they were so desperate to execute that they were seeking dates of execution even when they knew they wouldn't have the drugs to perform them, or were unaware of this," Senior wrote. "It is hard to figure out which is worse.

Deputy Attorney General Michael Quinn, the lead government attorney handling the execution, said he didn't know when prison officials had told him of the problem with the sodium thiopental. Quinn declined further comment and referred calls to the attorney general's press office, which in turn referred questions to the Department of Corrections and Rehabilitation. Prison department spokeswoman Terry Thornton declined comment.

In his filing to Fogel, Quinn didn't address the issue of expiring drugs. Instead, he urged the judge to allow the execution to proceed, arguing the state's new lethal injection regulations protect inmates from pain.

It was Fogel who ordered a halt to California executions in 2006 and ordered prison officials to overhaul the lethal injection process.

Prison authorities responded by building a new death chamber, overhauling the way executions teams are selected and trained, and making several other changes to the state's lethal injection procedures to comply with Fogel's order.

Fogel refused to block Brown's execution last Friday, saying it appeared the state had made significant process in improving its procedures.