The surprising discovery of World Trade Center steel in the past week raises more questions about what was left at ground zero in the cleanup after the 2001 attacks and how the service road was created in the first place.

The steel, found during a dig for human remains that has yielded nearly 300 bones in the past three months, includes two heavy beams that were stacked horizontally in the landfill, as if moved and placed there, a person with direct knowledge of the discovery told The Associated Press. The person was not authorized to publicly discuss the findings and insisted on anonymity.

The discovery was confirmed by officials for the city and Port Authority of New York and New Jersey, which owned the trade center.

The columns were about 18 feet long and perhaps 60 tons each. Officials believe the steel columns, located a week ago just 2 to 3 feet below the surface of the road, were deliberately set there at some point during the cleanup, perhaps to stabilize heavy machinery in use at the time.

Deputy Mayor Ed Skyler, who is overseeing the search for remains, declined to speculate on how the steel might have ended up where it did.

Digging was halted in the immediate area surrounding the steel columns until the Port Authority removes the steel. The columns will be put into storage at a hangar at Kennedy International Airport, agency spokesman Steve Coleman said Wednesday. The hangar stores all sorts of artifacts from the trade center, including what was believed to be the last column removed from the site in May 2002.

The person with knowledge of the discovery told the AP that three connected steel columns that once formed the facade of the trade center were also found below the road. Another column was found on the other end of the trade center site, where the Port Authority is building a retaining wall for three planned office towers, the person said. Unlike the stacked columns, this steel appeared to be burned at one end.

Officials involved in the initial cleanup have said that some steel pierced the ground as it fell and later was cut off above street level to speed up parts of the cleanup.

Coleman said the two heavy columns were the only steel found in the service road in the three-month-old search for remains. City officials confirmed that other steel had been found beyond the two heavy columns.

Throughout the renewed search for remains, crews had been finding smaller bits of debris from the towers as they dug into the material under the service road.

In December, Skyler expanded the search in that area because of the discoveries of small scraps of steel, electrical wires, computer parts and office carpeting -- but nothing that came close to the major pieces of trade center steel.

"We've been finding material from the buildings throughout the haul road, so in that context it's not that surprising," Skyler said. "What's most important to us is locating remains that we can find and returning them to the families."

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