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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Scientists used modern forensic techniques to review the 'cold case' and determine the victim was probably killed by two blows to the head.
US computer science expert says "endpoint" of lethal drone technology is killer robots that choose targets via artificial intelligence.
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