The elevators were a tragic exception to an otherwise successful evacuation that resulted in the survival of 99% of the people who worked below the floors where the jets crashed… Newly installed safety devices condemned many people to death. To comply with building codes, the World Trade Center since 1996 had been adding locks that made it impossible for passengers to force open the doors of stalled elevators. These locks, called “door restrictors,” had been added to about half of the 198 elevators in the twin towers. Nobody is known to have escaped from an elevator locked by a door restrictor.
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~ 9/11 Memorial Museum works through nation’s pain to honor victims … is set to be dedicated and on May 21 [2014] will open to the public.