As New York prepares to mark the 25th anniversary of the September 11, 2001 attacks, the city has released a substantial collection of previously undisclosed documents suggesting that government officials minimized or inaccurately described the dangers of the air after the collapse of the World Trade Center towers.
At a news conference on Tuesday, Mayor Zohran Mamdani announced the publication of approximately 170,000 pages concerning health problems linked to the attacks at the World Trade Center complex.
Mamdani said the release would provide “accountability around city government’s response to September 11 that New Yorkers have been denied for years”.
The announcement drew fresh attention to long-standing concerns that US officials allowed workers and residents to return to Lower Manhattan before the full extent of the airborne hazards was understood.
“It would be one thing if government had stood alongside survivors and provided them with everything they needed at every step of the way. And yet, we know that could not be further from what actually happened,” Mamdani said.
“People got sick because the leaders they trusted lied and told them they were safe to breathe in toxic air.”
On September 11, 2001, two hijacked planes struck the World Trade Center’s Twin Towers, bringing them down and killing 2,753 people at the site. A vast cloud of dust spread across Lower Manhattan, while fires continued to burn in the rubble for months.
Thousands of police officers, firefighters and construction workers spent time in the contaminated dust, often without adequate protective equipment.
Within weeks of the collapse, employees and residents were also permitted to return to nearby buildings, including One Liberty Plaza, which had been damaged during the attacks.
Many people who worked or lived near what became known as Ground Zero have experienced declining health since then. Some developed respiratory or digestive illnesses soon after the attacks, while others later developed conditions that took years to appear, including cancer.
What the records contain
The release includes an October 2001 memo sent to then-Deputy Mayor Robert Harding that assessed the city’s potential legal exposure following the attacks.
The so-called Harding Memo anticipated as many as 10,000 lawsuits against the city over issues including “toxic exposure” from contaminated air and “faulty” safety equipment.
It also set out ways the city could “limit” its liability, including by urging Congress to establish a victims’ compensation fund and seeking indemnification from the federal government.
A separate memo released in February 2002 described officials’ concerns that criticism from US Representative Jerry Nadler could create “major public relations problems” and invite a “barrage of lawsuits”.
Ester Fuchs, a former special adviser to then-Mayor Rudy Giuliani, cited Nadler’s allegation that the government suppressed documents showing asbestos levels “higher than acceptable” around the attack site.
Fuchs acknowledged that “there is at least a low level of asbestos in the dust in many buildings in lower Manhattan” and said the city would need to act if Nadler’s claims were accurate.
Asbestos, which was used in the Twin Towers’ construction, is a known carcinogen associated with lung scarring and mesothelioma, a type of cancer.
“At the least, we should discontinue telling people to clean their apartments with wet mops and rags,” Fuchs wrote, challenging guidance previously issued by the city.
Why the records are being released now
For months after the attacks, city and federal officials repeatedly assured residents, workers and first responders that air-quality levels were safe.
Nevertheless, questions about exactly what officials knew regarding airborne contaminants—and when they knew it—have persisted for years.
The release resulted from a lawsuit brought by advocacy groups including 9/11 Health Watch, which sought access to records on public health after the attacks.
During his Tuesday remarks, Mamdani highlighted the group’s multi-year legal effort and criticized successive city administrations for failing to act in the public interest.
“Administration after administration has ignored those calling for answers and clarity, instead choosing to bury them in legal arguments and in red tape,” Mamdani said. “We will do no such thing.”
The mayor said more records would be released over the following year and suggested that “millions” of additional pages could eventually become available.
Survivors and victims’ advocates joined Mamdani at the conference, including comedian Jon Stewart.
Stewart honored survivors who pursued government transparency while also coping with serious medical conditions.
“I’m not saying that the information may have changed the outcomes, unfortunately, for their families,” Stewart said.
“But I guarantee you it would not have been the struggle that it was to get people to recognise that what they all knew and what we all knew who live in downtown Manhattan: that there was poison in the air and on the ground.”
In a statement, 9/11 Health Watch welcomed the release and thanked labour unions, community organizations and other advocates for their efforts.
“For 25 years, four different Mayoral administrations kept from the public, the U.S. Congress, and the City Council documents showing what the City actually knew about the danger of the toxic chemicals in Lower Manhattan and Western Brooklyn,” said Benjamin Chevat, the group’s executive director.
Chevat emphasized that officials continued publicly describing the air as “safe and acceptable” even while aware of its dangers.
How many people have been affected?
Nearly 3,000 people died in New York on September 11, 2001, in an attack involving four hijacked planes. One plane struck the Pentagon in Washington, DC, while another crashed into a Pennsylvania field after passengers fought the hijackers.
According to the World Trade Center Health Program, about 4,343 people have since died from illnesses linked to the attacks.
The US Centers for Disease Control and Prevention estimates that 400,000 people were exposed to toxic contaminants, severe stress and hazardous conditions that put them at risk of physical injury.
Mamdani called the release “the right thing to do,” although it could prompt a fresh wave of lawsuits accusing the city of withholding information.
“We hold an obligation each of those New Yorkers to ensure that ‘never forget’ is not just a platitude, but that it is something material,” Mamdani said, invoking a phrase commonly used in remembrance of the attacks.
Stewart said the release was not only about uncovering what the local government knew but also about improving victims’ access to healthcare in the future.
“There’s more work to be done,” he said.
