SAN FRANCISCO — A former federal air marshal fired three years after leaking security information to the news media has suffered a legal setback in his bid to regain his job.

The 9th U.S. Circuit Court of Appeals ruled on Sept. 16 that the Department of Homeland Security properly classified the information as "sensitive" and didn't violate a federal law that protects government whistleblowers when it fired Robert MacLean.

The department dismissed MacLean in April 2006, three years after he gave a reporter an embarrassing but routine memo on reducing hotel costs by eliminating overnight airline trips for marshals for a month. MacLean said he leaked the memo after his boss ignored his safety concerns.

Once the memo became public, the air marshal program said it was a mistake and no flight assignments requiring overnight hotel stays were canceled.

In firing MacLean, the Bush administration argued that MacLean should have known the unlabeled memo he received on his unsecured cell phone was considered "sensitive security information."

MacLean countered that there was no way to tell that air marshal officials would designate the cost-cutting plan years later as sensitive national-security information.

The appeals court also rejected his argument that leaking the memo was protected by the whistleblower law, a decision that will hurt his challenge to his firing before a federal personnel board. That case was on hold pending the appeals court decision in MacLean v. Department of Homeland Security.

Gregory Alter, a spokesman for the Transportation Security Administration, which is part of the Homeland Security Department, declined comment because of the pending personnel matter. Peter Noone, MacLean's lawyer, did not return a call for comment in time for this story.