Former airport contractor Birke said he had suspicions about whether the fire watchers at MIA worked all the hours they were paid for.

"I would walk through that terminal at night and I could never find the fire watch, " said Birke, 63, who is now retired from Turner Austin and living in rural Florida. "They weren't doing anything, except collecting all this money."

But because he feared that the fire department's inspectors could expand fire watch with the stroke of a pen, Birke said he never complained in writing to fire or airport officials.

Van Meter said the department's inspectors order fire watches only when they are required by the fire code, and they are lifted the moment the alarms are repaired.

Under the rules, there is nothing to stop an inspector who declares a fire watch from also earning money working it.

At the West Dade library, an inspector ordered a 24-hour fire watch beginning March 11, 2005 - although the library is open for no more than 12 hours a day. He took the first 13-hour overnight shift himself, earning $1,202, records show.

As long as the underlying reason for the fire watch is legitimate, Mena said he sees no problem with an inspector making money from a job he assigns. "We're pretty comfortable with our checks and balances on that side of the house."

For nearly four weeks, two firefighters were posted in the library round-the-clock.

"It was not an expense we were happy to incur, " said William Urbizu, assistant director of the county library system, "but shutting down would have been unacceptable to the community."

Mena said library officials specifically requested the 24-hour service to protect a rare-book collection.

Urbizu said that's not true. "Rare books?" he said, laughing. "We have no rare books at that location."

Regardless, the repair job stretched out longer than anyone expected. Library officials spent March determining the nature of the problem and drawing up bid specifications for a contract to fix it, Urbizu said. Then the first month's bill, for $54,899, came with a costly surprise: Because of union rules, the firefighters had to be paid overtime.

Library officials persuaded the fire department to cut the number of firefighters on guard, records show, and the April bill came down to $32,117.

The fire watch continued through September, when the alarm system was finally replaced. The ultimate bill for taxpayers, $155,478, would have been much higher if the fire department had not agreed to use lower-ranking, lower-paid firefighters in the final months. Urbizu said he remains puzzled about why lieutenants and captains were ever necessary.

No one earned more at the library than Lt. Hector Noel, who described the work as a test for the senses. "You walk the halls, using basically your nose and your eyes, " he said. "It's just sniffing, sniffing, sniffing."

When not patrolling, Noel said, he caught up on the financial news in the library's periodicals section. The inherent tedium is one reason the department has difficulty filling all the available shifts and sometimes has to turn to higher-ranking officers, Noel said. "It's such a grind, a lot of the guys just couldn't take it. But I'm really into reading."