New York City on Tuesday released more than 170,000 pages of records showing that officials knew the air quality around Ground Zero following the Sept. 11, 2001, terror attacks was unsafe despite repeatedly assuring residents and first responders the air was safe to breathe.

The documents — including previously unreleased air quality reports, contamination records and memos between officials — were posted online by New York City Mayor Zohran Mamdani’s office days ahead of the 25th anniversary of the attacks.

“On Friday, we will mark 25 years since the worst tragedy to ever befall our city, the darkest day New York City has ever known,” Mamdani said at a news conference surrounded by 9/11 survivors and families. “And yet, the devastating truth is that the suffering did not end once the smoke cleared and the dust settled. For so many New Yorkers who lived or worked or studied near Ground Zero, and for the thousands of others who worked on the pile, recovering those we lost and clearing the rubble, that was only the beginning.”

Nearly 3,000 people were killed in the attacks. But according to Mamdani, more people have died from 9/11-related illnesses than were killed on the day itself.

“People got sick because the leaders they trusted lied and told them they were safe to breathe in toxic air,” Mamdani said.

The mayor was joined by Jon Stewart, host of The Daily Show and a longtime advocate for first responders and people with 9/11-related illnesses.

Jon Stewart and New York City Mayor Zohran Mamdani attend a press conference on Sept. 8.

Jon Stewart and New York City Mayor Zohran Mamdani attend a press conference on Sept. 8.

(Jeenah Moon/Reuters)

“There was poison in the air, and on the ground, and in the windowsills, and in your air conditioners and covering your pets and your clothes, and it stayed there for months,” Stewart said. “Everyone knew. Now it’s very clear that the city knew as well.” 

The records, which had been stored in 68 boxes in a city office, were discovered last year, according to the mayor’s office, and posted to a searchable online database. They include the so-called Harding memo, sent to then-Mayor Rudy Giuliani’s deputy mayor, Robert Harding, in which officials discussed ways to limit the city’s liability for toxic exposure.

Their release follows the settlement of a pair of lawsuits brought by 9/11 Health Watch, which had sued to force their publication. More documents are expected to be posted to the portal in the coming months.

“The very least our city owes the families, survivors and first responders whose lives were forever changed by the September 11th attacks is transparency and accountability. … For too long, New Yorkers have had to fight for access to records that should have been available to them in the first place,” Mamdani said in a statement.

Mamdani is scheduled to attend more than a half-dozen events this week marking the 25th anniversary of 9/11.

In an appearance on Newsmax over the weekend, Giuliani said Mamdani’s decision to attend them “offends” him, repeating baseless and Islamophobic claims about the city’s first Muslim mayor and comparing him with the 9/11 terrorists. 

Mamdani declined to respond directly when asked about Giuliani’s comments on Monday.

“I’m proud to be the mayor of this city. I love this city. I love this country,” Mamdani said. “And what I want this week to be a focus on is the families whose loved ones were stolen from them 25 years ago in the horrific act of terror of Sept. 11, and a focus also on the first responders who did everything they could for this city.”