New York City plans to start sifting through earth and debris recovered from the World Trade Center site on Monday to look for the remains of victims from the attacks of September 11, 2001, officials said on Friday.
The city's Office of the Chief Medical Examiner on Friday advised families of the dead about the new sifting operation, the first since 2010, a spokeswoman said in a statement.
The Medical Examiner's office has identified remains of 1,634 people out of 2,752 killed when suicide hijackers crashed into the twin towers, leaving more than 1,000 families without any physical remains of those who died.
After the initial cleanup of the site, the city scaled back operations to search for remains, drawing criticism from families of the dead, who said they could not properly grieve. The city widened its search again in 2006.
The next search will comb through 590 cubic yards (451 cubic meters) of excavated material taken from and near the World Trade Center site, said Caswell Halloway, deputy mayor for operations, in a memo to Mayor Michael Bloomberg made public by the Medical Examiner's office.
Much of the site known as Ground Zero is a construction zone for new skyscrapers and a memorial where the twin towers once stood.
The building under construction known as One World Trade Center has surpassed the Empire State Building as the tallest in New York and, when completed, would be the tallest in the Western Hemisphere at 1,776 feet.