At WTC site, a cleanup of unparalleled size

From tall, telescoping cranes, bulldozers and power shovels to bucket brigades, the cleanup at the shattered World Trade Center is as basic as it gets in the demolition industry.

The difference: Ground zero is also a crime scene -- the site of the biggest mass murder in American history.

Working behind the machines digging into layers of debris, hard-hat workers, firefighters, police officers and volunteers proceed cautiously to avoid collapsing gaps in the 150-foot heap of rubble where survivors might be trapped.

The crews must also preserve potential evidence for FBI investigators, such as debris from the two jetliners that hijackers crashed into the 1,300-foot twin towers last Tuesday.

Even with the heavy equipment, it is a labor-intensive operation to rival the pyramids of Egypt. Never in history has one 110-story skyscraper fallen down, let alone two, at the same time and place. Workers use power saws, crowbars and their hands to slice and pry at the wreckage.

Officials were close Sunday to finalizing contracts with four New York construction companies to do the heavy lifting.

At the scene, Mark Loizeaux, a Maryland-based demolition expert, was running the operation for one of the companies, Tully Construction. At his command was a battalion of power tools: a 110-ton hydraulic crane, a 250-ton hydraulic crane, two 300-ton “crawler” cranes and eight hydraulic excavators with attachments that can “grab steel, cut steel and rip out debris,” Loizeaux said.

In the course of the day, he said, workers penetrated for the first time into the lowest level below the towers, a commuter railroad station 80 feet underground. They found some “voids” -- pockets in the rubble -- but no one alive.

“We are basically opening up voids to support fire department and government search and rescue operations,” Loizeaux said by phone from the site. “We take a layer of debris off, let them go in and search, take another layer of debris off.

“Everybody is doing whatever it takes to support the search and rescue, to stabilize the situation and to assist the utility crews.”

Several building experts have said the towers collapsed because blazing jet fuel melted steel braces, causing outer walls to peel away in a shower of steel pillars and glass. The floors -- unsupported by internal pillars -- “pancaked” downward, gaining momentum from ever-increasing weight.

The towers were built to withstand a strike by a Boeing 707 -- the largest aircraft at the time, but much smaller than the jets that struck Tuesday.

Within hours after the mortally wounded monoliths vanished in vast, opaque clouds of cement dust, bulldozers, excavators and other heavy-duty construction machines were converging on the scene.

A flatbed truck carrying a huge crane trundled down Second Avenue under police escort, past the city morgue where the first Trade Center dead were arriving. Scores of other machinery lined the streets near the disaster site.

At night powerful floodlights, some borrowed from a film studio in Queens, illuminate the scene, silhouetting other financial district buildings in an eerie tableau visible from the boroughs of Brooklyn and Staten Island, up to five miles away.

Dump trucks take the rubble to Staten Island, where it is spread out in a field near the city’s recently closed Fresh Kills landfill. There, teams of FBI agents and New York City detectives sort through the debris by hand, seeking anything that might add to the file of criminal evidence.

The debris is being moved at a rate of about 3,000 cubic yards a day. How long it would take to clear the estimated 2 million cubic yards covering 16 acres of lower Manhattan is unknown.

To Tom Rowe, a New Jersey firefighter working as a volunteer, the material collected by the bucket brigades seemed insignificant. “It’s like if you filled your back yard with sand, and you tried to empty it with a teaspoon.”

All across the country, people in the building industry -- architects, engineers, construction and demolition experts -- have watched the World Trade Center operation with eyes that see more than just the television pictures of workers dwarfed by their project.

“I would say it takes a task and multiplies it by 100 times in terms of the level of care,” said Bill Walsh, operations manager for Engineered Demolition, an Idaho firm that specializes in bringing down large buildings.

“It’s most unusual,” said Jay Lubow, a New York architect who has done work at the World Trade Center. “People seem to think you can just start picking up the rubble. But because it fell randomly, it’s like ‘Pickup Sticks’ -- you pick up a stick on top, which will then move sticks on the bottom.”