The voices captured on those discs track the unseen callers as they are passed by telephone from one agency to another, moving through a confederacy of municipal fiefdoms — police, fire, ambulance — but almost never receiving vital instructions to get out of the buildings.
No more than two of the 130 callers were told to leave, the tapes reveal, even though unequivocal orders to evacuate the trade center had been given by fire chiefs and police commanders moments after the first plane struck. The city had no procedure for field commanders to share information with the 911 system, a flaw identified by the 9/11 Commission that city officials say has since been fixed.
The tapes show that many callers were not told to leave, but to stay put, the standard advice for high-rise fires. In the north tower, all three of the building's stairways were destroyed at the 92nd floor. But in the south tower, where one stairway remained passable, the recordings include references to perhaps a few hundred people huddled in offices, unaware of the order to leave.