Twenty-five years after the September 11 attacks, New York City has opened a huge new chapter in the 9/11 record.
Mayor Zohran Mamdani announced Tuesday that the city is releasing more than 170,000 pages of previously unavailable records documenting the government’s response to the attacks and their aftermath, particularly concerns over air quality and health risks around the World Trade Center site.
The records are being made available through a new public portal and include material sought for years by 9/11 survivors, first responders and advocacy groups.
And the central question behind the release is stark:
What did New York City officials know about the toxic conditions at Ground Zero and when did they know it?
The initial release contains approximately 170,000 pages covering health concerns, air quality and the city's response following the attacks.
Among the records are the Harding Memo, a collection of records known as the “68 boxes” that were located in 2025 after years of requests, and documents relating to World Trade Center 7.
The city says the archive will not stop with this first release.
Additional records are expected to be added over the next 12 months as officials continue reviewing the city's files. Personally identifiable information has been redacted where necessary.
Immediately after the towers collapsed, Lower Manhattan was covered by dust, smoke and debris from the disaster.
For years, questions have persisted over the safety of the air around Ground Zero and whether government officials adequately communicated the risks to rescue workers, residents and others in the area.
Newly released records are now drawing renewed attention because some documents indicate that officials were dealing with concerns about hazardous conditions while the public was receiving assurances about air safety.
That does not automatically mean every official involved knew the full extent of the health risks or deliberately misled the public. The significance of the release will depend on what the documents establish when they are examined in full.
But the records could provide a much more detailed picture of the decisions made during those chaotic weeks and months.
One of the most striking elements of the release is the inclusion of records known as the “68 boxes.”
The records were not located until 2025, despite multiple Freedom of Information Law requests seeking material related to the city's response to 9/11.
Their eventual discovery became part of a broader legal battle over access to the city's historical records.
Now, those documents are being placed in the public archive.
The release also comes after the city reached a settlement with 9/11 Health Watch, an advocacy organisation that had pursued legal action seeking access to records concerning air quality and health risks following the attacks.
The settlement brings an end to two lawsuits and creates a framework for continued disclosure.
The city has committed $34 million in its fiscal 2027 budget to create and maintain the public records portal.
The timing is significant.
The release comes just days before the 25th anniversary of the September 11 attacks, when New York will once again turn its attention to the victims, survivors and first responders whose lives were permanently changed.
Mamdani has separately designated September 11 as a city Day of Remembrance and Service, saying the anniversary should be about remembering those who died as well as those whose lives were affected in the years that followed.
His administration has increasingly linked the commemoration of 9/11 with the long-term health consequences of the disaster.
Earlier this month, the city and FDNY also released a 25-Year Health Impact Report documenting the long-term health effects experienced by FDNY members involved in the World Trade Center rescue and recovery effort.
The biggest impact may not come from one explosive document.
Instead, the archive could help researchers reconstruct a timeline:
What officials knew → what they measured → what they communicated → what decisions they made.
That timeline could matter enormously for understanding the health crisis that followed 9/11 and the government's handling of it.
For first responders and survivors who have spent decades seeking recognition and health support, the documents could also provide historical evidence about the conditions they were exposed to.
The 2001 attacks killed thousands immediately. But the health consequences did not end when the rescue operation ended.
First responders, residents and workers exposed to the conditions around Ground Zero have faced respiratory illnesses, cancers and other serious health problems over the years.
The federal World Trade Center Health Program and related compensation programmes were created because of that long-term impact.
The newly released records could therefore become more than a historical archive.
They could become evidence in an ongoing conversation about government accountability, public-health warnings and the responsibility to protect people during a disaster.
Twenty-five years after 9/11, New York is opening more than 170,000 pages of its own history.
The records don't automatically prove that officials intentionally concealed the dangers of Ground Zero.
But they could answer a question that has lingered for decades:
What did the government know about the air — and what did it tell the people breathing it?
And with more records expected over the next year, the 170,000 pages released today may only be the beginning.
