From a recent (Feb 28, 2008) Foghorn article…
According to USF Project Management project planner J.J. Thorp, the conflict began in late December, when the library building underwent a routine inspection. When they got to the atrium, the officials noticed that the doorway between the atrium and the main library building was marked with a green emergency exit sign, yet that doorway was locked at night and days when the library was closed. Having an emergency exit door locked is hazardous and in violation of building codes, so officials mandated that the atrium either no longer remain open at night or else the library leave the adjoining doors unlocked during that time, which would be a significant security risk for the library full of expensive books and computers.
Since the initial inspection, the facilities management team has worked closely with the city, and removing the exit sign was agreed upon as an amenable solution for all parties concerned. The exit doors that lead outside on the opposite wall are sufficient to meet the room’s minimum requirement for emergency exits. Now the only steps left in the process are to have the illicit sign removed, which should be done in a matter of days, and to have city inspectors verify that the sign was in fact removed, which could take up to two weeks.
You can read the entire article at the Foghorn website.