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After 9/11: Cleaning Up America’s Worst Terrorist Attack


When the Twin Towers were destroyed by Al-Qaeda hijackers on September 11th, 2001, it was the deadliest and most destructive terrorist attack in history. Thousands of lives were lost, and two of the most iconic buildings in the world crumbled. Yet, the consequences of that destruction are still being felt to this day. While the original Twin Towers were a Megaproject in their own right, one that we’ve covered on this channel, the response was also an incredible, large-scale effort. First, the coordination of the New York Fire Department, Police Department, Coast Guard, and Emergency Medical Staff was on a scale unlike anything seen before. The naval evacuation of people from the area has no parallel, even compared to the most famous wartime retreats.

With the situation under control, workers dug through the rubble, sometimes uncovering survivors or the remains of those lost. Following search and rescue, the cleanup effort required months of work from tens of thousands of men and women, many of whom lacked the proper equipment to safely do their job. The final step in recovery was to rebuild, leading to the construction of the sacred 9/11 Memorial and One World Trade Center, commonly called the Freedom Tower.

While some wounds from the 9/11 attacks are still healing to this day, there is no doubting the herculean effort of those who worked to recover from America’s worst terrorist attack.

The Attack

On September 11th, 2001, 19 Al-Qaeda affiliated terrorists hijacked four separate airplanes in American airspace. Financed and organized by the Saudi fugitive Osama Bin Laden, many of the eventual terrorists had spent the last year living in the US and attending flight schools. The attackers boarded planes on America’s east coast, sneaking knives and box cutters through security. The aircraft were all scheduled for cross-country flights to California, meaning they were full of jet fuel, a powerful accelerant for fires caused by their collisions. 

The terrorists had four targets— the World Trade Center’s Twin Towers, the Pentagon, and somewhere in DC, likely the White House or US Capitol. The Twin Towers were two of the world’s tallest buildings, housing tens of thousands of New York office workers, a symbol of pride for the nation’s largest city.

At 8:46 a.m. on 9/11, that would change forever. 

The Al-Qaeda terrorists flew their hijacked Boeing 767, American Airlines Flight 11, and crashed it into the North Tower’s northern face, striking between the building’s 93rd and 99th floors. The impact caused incalculable structural damage, and more than 3,000 of the plane’s 10,000 gallons of jet fuel ignited, setting the building aflame and further weakening the architectural support.

Barely a quarter of an hour later, the terrorists flew another 767, United Airlines Flight 175, into the South Tower’s southern facade, hitting between the 77th and 85th floors. While this collision was less direct, the skyscraper’s demise came much quicker. Between the impact and the burning jet fuel, it took less than an hour to collapse as the world looked on. 

The North Tower didn’t last much longer, folding in on itself after 102 minutes of fires, caving in at 10:28 a.m. Less than two hours after the first plane struck, two of New York’s most prominent buildings laid in piles of rubble, and thousands of men and women were dead.

However, the damage didn’t end there. As the skyscrapers collapsed, the foundations and structure of many nearby buildings were also weakened. World Trade Center 7, the third tallest structure in the WTC complex, succumbed to fires and fell at 5:21 p.m. on the day of the attack. The Marriot WTC Hotel also collapsed that day, shortly after the towers fell. At least five buildings in the surrounding area were condemned due to toxic conditions caused by the smoke.

On the ground, the air was just as toxic. Not only was the smoke from fires harmful for the lungs, but the materials in the air from the collapsed buildings were hazardous to inhale. Altogether, at least 2,753 people died in the attack, excluding the hijackers, though that number has often been called an underestimation. Over 2,100 of that number were civilians, while the rest were firefighters, police, and medical staff. However, if not for the local first responders’ heroic efforts, the damage could have been much worse.

First Responders and Evacuation

From the first plane’s impact with the North Tower, first responders had mere minutes to do their best to limit the damage. Within five minutes of the attack, the New York City Fire Department set up an incident command post in the South Tower lobby. Initially led by FDNY Chief Joseph Pfeifer and his crew from the local 1st Battalion, the firefighters orchestrated the first step: evacuation.

More than 1,300 people were trapped in the floors above the plane’s impact, but the evacuation effort for lower floors began immediately. With a suspected 50,000 workers in the building, though, evacuation efforts for such a threatening attack required immense organization. The worst-case scenario would be that everyone attempted to evacuate at the same time, leading to a traffic jam and resulting in fewer people escaping.

In alignment with World Trade Center protocol for a large fire, people working on floors directly below the impact were prioritized. However, with debris falling from the building already, exiting from the main entrance was not an option. So, firefighters led tenants through the underground shopping mall beneath the WTC’s central plaza.

While this happened, authorities at the South Tower piped an announcement through the building that the situation was under control and that everyone inside should stay put. Thankfully, many people ignored this advice and began exiting the building immediately. 

When the second plane struck the South Tower, it became clear that this was not an accident, and the evacuation effort was increased. The FDNY chief moved their command center across the street, and first-responders from across the region flooded into Lower Manhattan to aid the struggle. Firefighters scaled the building’s stairs to reach people trapped in elevators or to help them find the safest exits, all while the fire raged on.

Due to the unimaginable urgency, many firefighters didn’t have time to check-in at their command post, instead bravely running into the buildings with little knowledge of the plan. Men and women who weren’t on duty arrived at the scene to help out without their equipment. Radio communications were nearly impossible, as thousands of first responders were on the airwaves, and the communications infrastructure was severely damaged. Sadly, this meant that many firefighters didn’t hear the evacuation order as the buildings began to crumble, leaving hundreds of them trapped inside as the skyscrapers collapsed down on them. At least 340 firefighters were killed.

Of course, firefighters weren’t the only heroes that day. Doctors and other Emergency Medical Staff set up five triage centers throughout the area, though many of them were forced to relocate as debris filled the air, making their jobs much more difficult. Dispatchers at 9-1-1 call centers were overwhelmed by the flood of incoming information, rendering them nearly incapable of managing the situation. Hospitals throughout the Greater New York area donated heaps of equipment for airway and vascular control. However, these triage centers remained underutilized— injuries sustained in the attacks were perceived as either too grave for the triage’s capabilities or too minor to seek immediate treatment.

The NYPD provided invaluable support to the effort, arriving on the scene with helicopters, allowing them to assess the situation from the air. Thousands of troopers focused on evacuating the surrounding area, one of the more densely populated neighborhoods of New York. With few options for command centers, the NYPD set up temporary headquarters in a Burger King near the World Trade Center. Many police were among the first people to enter the buildings, and at least 60 officers from the NYPD or the Port Authority Police department were killed.

One critical part of the operation was the US Coast Guard’s leadership, who called for all ships in the area to assist in the evacuation of Lower Manhattan. Led by the Coast Guard Auxilary and aided by many small vessels that happened to be in the area, somewhere between 500,000 and 1,000,000 people were evacuated from the island within eight hours of the attacks, surpassing Dunkirk as the largest maritime evacuation in history. 

With the towers collapsed and everyone evacuated from the area, the Fire Department got to work putting out the massive flames that raged on. With the blaze controlled and the situation seemingly calming down, the next day marked the start of the aggressive search and rescue effort by the FDNY and NYPD. On September 12th, eleven people were pulled from the rubble alive, including six firefighters and three police officers. Two Pennsylvania officers, who crossed state borders to respond to the emergency, were pulled out from under 10 meters of crushed concrete. 

The final survivor was extracted from the debris more than 27 hours after the attack. However, another 80 survivors, some of whom could reach their cell phones and make distress calls, died beneath the rubble that day, most of them buried too deeply beneath the wreckage to have any chance for rescue.

Of all of the terrible news of that day, perhaps the slightest silver lining was that, despite early reports that more than 50,000 people were in each building, the total was likely less than half of that. Thanks to the brave efforts of the first responders, casualties were limited. Still, the attacks marked the deadliest day in American history. But the work was not over.

Recovery and Cleanup

With such a massive effort required to clean up the Twin Towers’ site, it called for contributions from more than just the local first responders. Ironworkers, structural engineers, electricians, construction managers, and people from countless other relevant professions were on the scene to ensure the safest and quickest recovery effort. Of course, it would not be a quick effort, as it would take more than eight months before the site was cleared of debris.

View of the recovery camp from inside the fifth floor of the Pentagon on September 14th. The damage was caused by a hijacked commercial jetliner crashing into the Pentagon on September 11th. The terrorist attack caused extensive damage to the Pentagon and followed similar attacks on the twin towers of the World Trade Center in New York City.

Altogether, about 2 million tons of rubble, known as The Pile, lay on Ground Zero. New York Mayor Rudy Giuliani placed the NYC Department of Design and Construction over the effort. They divided the pile into four quadrants and assigned teams of thousands to dig through it with the help of several cranes. Going at a rate of about 50,000 tons per week, the project was done one bucket at a time. Workers filled five-gallon buckets with all of the debris they could while investigators searched through the buckets for human remains. All throughout the cleanup, workers reported the smell of rotting human flesh seeping up through the crevices between the ruins.

Ironworkers cut steel beams into more manageable sizes to be hauled off. Much of the steel from The Pile was reused, sometimes before it could be analyzed in post-collapse investigations. Much of the material was used to build memorials for victims of the tragedy, while others were put to more typical uses. Twenty-four tons of steel from the site was used to construct the USS New York, a 200-meter long military vessel.

Of course, the work wasn’t easy, and it was filled with safety hazards. Some of the risks were considered, while others were totally forgotten. Beneath the World Trade Center complex was a massive parking garage, wholly crushed when the buildings fell. An estimated 2,000 automobiles sat beneath the rubble, with an average of five gallons of fuel in their tanks. Once they reached this depth, workers noticed that many of the cars had exploded in the flames. Thankfully, machinery operators were careful to avoid causing similar detonations during the cleanup.

Unfortunately, the other safety hazard was not as well heeded. While national agencies like Federal Emergency Management Agency hold workers to strict guidelines surrounding personal safety equipment, the New York DDC did not. As a result, the overwhelming majority of the cleanup crew labored without wearing respirators, a vital piece of equipment for fighting the long-term damage of inhaling dangerous chemicals found on sites like Ground Zero. 

In the decade following 9/11, test results showed that respiratory problems plagued those people who helped in the hours and months following the attack. 99 percent of firefighters reported at least one new respiratory problem, typically chronic airway disease. Instances of cancer showed alarmingly higher rates than similar populations around the world, including among crews working after cleanups. Even the emergency medical teams, many of whom worked blocks away, showed a 22% increase in lung-related health issues. The battle to provide medical support for these first-responders is ongoing.

Altogether, 8 months after the cleanup began, the work was deemed complete. The process required about 9 billion dollars, including 5 for the labor and equipment for debris removal, 3 for overtime payments to uniformed workers, and another billion to replace essential equipment destroyed in the collapse, including a fire response vehicle. However, with the site cleared, the discussion of how to reuse the area could finally begin.


As early as July 2002, the Lower Manhattan Development Corporation began looking into building a new World Trade Center and a 9/11 memorial. The process was long and grueling for both projects, as officials worried about the repercussions of a misstep in such a delicate situation. Many early designs for the towers were rejected, as most architects attempted to emulate the original Twin Towers or build something in their footprint.

Instead, the towers’ site would house the monument. The memorial proceeded much quicker than the new World Trade Center, with the overseeing authority selecting a design in 2004. Centered around two massive pools that sit in the Twin Tower’s footprints, the acre-sized pools are surrounded by waterfalls cascading 10 meters into a central basin. The water continues to flow downward into the abyss, symbolizing the absence of the towers and the people who perished in the terrorist attack. The names of each and every victim are listed on the bronze parapets that surround the pools. With the sound of the crashing waterfalls, the memorial serves as a quiet place of reverence for residents of the otherwise noisy, bustling city. The monument was opened on the 10th anniversary of the attacks in 2011.

As for the new World Trade Center, the winning design was unveiled in June of 2005. Construction proceeded until the building was completed in 2014. Nicknamed the Freedom Tower, it stands at 541 meters tall, or 1,776 feet, a nod to the year of America’s founding. Arising from a 61 square meter base, the tower twists into the skyline with six sides. As the new tallest building in New York, One World Trade Center does its part in restoring the skyline.

Altogether, the project cost 4 billion dollars, bringing the total cost of clearing debris and replacing the Twin Towers to well over 13 billion. Another four buildings will be added to the complex in the coming years.

In ensuring that nothing like the 9/11 attacks ever happens again, the NYPD has undergone something of their own megaproject, arming for the event of another possible terrorist attack. With a force of almost 40,000 sworn officers and another 20,000 support staff, the agency has adopted new technology and weaponry to deter any threats. They’ve increased public displays of weaponry and, along with federal policy, have improved surveillance throughout the city. Though it’s never been officially confirmed, outside observers believe that they are now equipped with an arsenal capable of bringing down an airplane if a similar attack were ever launched against the city. 

In retrospect, the first-responders have been revered for their efforts in mitigating the consequences of the 9/11 attacks, but, hopefully, we’ll never see anything like it again.

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