NBC New York reports that the two workers have been secured using ropes, and emergency workers are trying to find a way of winching them to safety.
Parts of the streets below, on 57th and 58th streets and Eighth Avenue, have been closed off.
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Female inmates compete to create the most fabulous cell in a contest designed to ease the pain of being away from family at the holidays.
The actress, who recently got engaged to Prince Harry, will take part in festivities on the Queen's private estate in Norfolk.