Twenty-five years after the September 11 attacks, New York City Mayor Zohran Mamdani released more than 170,000 pages of internal records Tuesday that show officials misled people about the safety of the air around Ground Zero after the terror attacks.
“People got sick because the leaders they trusted lied and told them they were safe to breathe in toxic air,” Mamdani said during a news conference.
The move came just days before the U.S. is set to commemorate the 25th anniversary of the al Qaeda hijackings that killed nearly 3,000 people when passenger planes toppled the World Trade Center’s Twin Towers, damaged the Pentagon and crashed near Shanksville, Pennsylvania.
Comedian and activist Jon Stewart, an outspoken supporter of first responders who were sickened while searching for remains at Ground Zero, also spoke at Mamdani’s City Hall news conference.
“There was poison in the air, and on the ground, and in the window sills, and in your air conditioners, and covering your pets and your clothes, and it stayed there for months,” he said. “Everyone knew. Now it’s very clear that the city knew as well.”
Key findings from the documents, which were reviewed by The New York Times before Tuesday’s announcement, include:
• Asbestos levels in dust samples throughout lower Manhattan exceeded hazardous limits in the days after September 11.
• Asbestos and other contaminants were found above acceptable limits in dust and air in lower Manhattan.
• A November 2011 audit showed levels of the carcinogen benzene were still spiking in the air around the towers’ footprints.
• That audit also showed that the amount of asbestos in the air at the Fresh Kills landfill on Staten Island increased after the attacks.
• A woman who lived in lower Manhattan wrote a letter to the DEP in February that detailed alleged missteps by officials in removing contaminants from in and around her building.
Some 410,000 to 525,000 people were exposed to toxic dust in the wake of the attacks, according to Asbestos.com, including 90,000 rescue and recovery workers. As of 2025, more than 44,000 people had been diagnosed with cancers related to 9/11, according to the World Trade Center Health Registry, and more than 63,000 with a health issue related to the aftermath of the attacks.
The documents were discovered last year after being hidden from the public in 68 boxes stashed in a government office, city officials said.
The release of the records resolves a lawsuit filed by the advocacy group 9/11 Health Watch.
But the revelations in them could lead to new or amended lawsuits from people who suffered 9/11-related ailments, and bolster claims by people seeking payments from the federal September 11th Victim Compensation Fund.
A total of 2,753 people were killed at the World Trade Center, according to the latest statistics compiled by the New York City medical examiner’s office last month.
They include 343 city firefighters, 37 members of the Port Authority Police Department, 23 city police officers and eight paramedics and EMTs.
Former Mayor Rudolph Giuliani — who was in office at the time of the 9/11 attacks and was dubbed “America’s mayor” for his leadership — repeatedly vouched for the safety of the air following the attacks, even while acknowledging in late October 2001 that “sometimes the odor is terrible.”
“You smell it and you feel there must be something wrong with it. But what I’m told is that it is not dangerous to your health,” he said after the New York Daily News reported that toxic chemicals and metals had been released into the environment.
Giuliani’s successor, former Mayor Michael Bloomberg, also said in February 2002, “Every test that has been done says the air quality was in acceptable limits. I think some people are just never going to want to believe that.”
The records released Tuesday can be downloaded free of charge from a searchable city website, with Corporation Counsel Steven Banks saying in a message there that other documents will be added “on a rolling basis in the coming months.”
The available records include the so-called Harding Memo, which was sent to then-Deputy Mayor Robert Harding with the title “Legislative Alternatives to Limit the City’s Liability Relating to 9/11/01.”
“It provides insight into the City’s consideration of potential legal and legislative responses in the aftermath of the attacks, including concerns about the prospect of substantial litigation arising from toxic exposure and the adequacy of safety equipment,” Banks said.
Banks said the City’s Department of Investigations was now looking into what officials knew about air quality problems, when they knew it and why information may have been withheld.
During the news conference, Mamdani noted that “more people have died from 9/11-related illnesses than were killed on the day itself.”
“Administration after administration has ignored those calling for answers and clarity,” he said. “We will do no such thing.”
Stewart, creator and co-host of the satirical cable TV news program The Daily Show, said the records showed that the city didn’t realize the air in lower Manhattan was toxic until October 2001.
“So to be fair to them, they only buried that information for 25 years,” he said.
On Tuesday, following Mamdani’s news conference, a post on Giuliani’s X account, attributed to his staff, said, “The EPA said it was safe. They made a mistake. No one covered it up. Giuliani has 9/11 lung disease like so many others because he couldn’t be kept from helping the people.” (TheIndependent)