New York City Releases 170,000 Pages of 9/11 Air Quality Records, Revealing Early Knowledge of Toxic Risks

New York City has released more than 170,000 pages of previously undisclosed records about air quality following the September 11, 2001, attacks. The documents show that city officials at the time knew conditions around Ground Zero were unsafe to breathe despite repeated public assurances that the air was safe.

Mayor Announces Release Amid Growing Health Toll

Mayor Zohran Mamdani announced the release at a news conference Tuesday, framing the disclosure as a reckoning with the long-term human cost of the attacks.

“As the years pass and the human toll grows, we reckon with the cost of September 11th whenever another New Yorker is stolen from us too soon,” Mamdani said. “Now, close to 25 years later, more people have died from 9/11-related illnesses than were killed on the day itself.”

According to the 9/11 Memorial, at least 140,000 people from all 50 states have enrolled in the World Trade Center Health Program, and 49,000 have been diagnosed with certified WTC-related cancers. Mamdani said Tuesday that more people are eligible for assistance than are currently enrolled, including residents who lived near the site but have not received outreach and those who live outside of New York.

Cancer coverage was not included when Congress created the health program in 2011. It was added in 2012 only after a fight by advocates and a study showing elevated cancer rates among New York firefighters at Ground Zero. Nearly 3,000 people were killed on 9/11, but thousands more — including first responders who spent months working at the site — have since died from 9/11-related cancers and other illnesses.

Documents Released After Lawsuit by 9/11 Health Watch

The release resolves a lawsuit brought by the advocacy group 9/11 Health Watch, which had sued the city for the records.

Ben Chevat, the executive director of 9/11 Health Watch, said Tuesday the release of the documents will give people what they need to access federal assistance and will help kick-start additional research on health outcomes.

“Mr. Mayor, I want to thank you for being the mayor who, after 25 years, begins to answer the question: What did the city know about the dangers from the toxic cloud at Ground Zero, and when did it know it?” Chevat said at Tuesday’s news conference, addressing Mamdani.

Internal Memos Show Early Alarms About Toxins

The documents contain a fraction of the air quality reports taken at Ground Zero, but they also include crucial internal memos. These documents show officials raised alarms regarding environmental testing between October and November 2001, which regularly detected elevated levels of toxins, including asbestos and hard-to-detect chemicals that were dangerous.

Some documents show concerns about air quality were outlined in a white paper published by U.S. Rep. Jerry Nadler of New York, who sent a memo to then-Mayor Michael Bloomberg’s office in February 2002. Nadler outlined his concerns and belief that the Environmental Protection Agency had “neglected its responsibility for monitoring indoor air quality around Ground Zero.”

Nadler told the mayor’s office that shortly after the attacks, then-EPA Administrator Christine Todd Whitman misled the public by publicly declaring that the air was “safe to breathe,” but that the statement was made before any government test of indoor air quality had been conducted, the documents show.

Nadler also wrote to the mayor’s office about findings by University of California, Davis, scientists which showed the air contained “startling concentrations” of lung-penetrating, ultra-fine particulate matter that could “lodge deep in the lungs.”

News reports from February 2002, five months after the attacks, show Bloomberg, who succeeded Rudy Giuliani, said “every test that has been done says the air quality was in acceptable limits. I think some people are just never going to believe that.” A spokesperson for Bloomberg declined to comment Tuesday.

EPA Administrator Defends Agency’s Actions

Whitman said in a statement Tuesday that her comments about the Ground Zero site’s air quality “were based entirely on the analysis done by EPA scientists.”

“Within days, the EPA had put up a website with all the data available, which they frequently updated so that it was all public — the goal was as much transparency as possible. Everyone at the EPA did the best they could with the information, tools, and knowledge available at the time,” she said in the statement.

Whitman said EPA officials repeatedly distinguished between conditions at the site and the air elsewhere in the city and warned of the risks to workers at Ground Zero. She added that the EPA did not control the worksite — which she said New York City oversaw — and had no authority to regulate indoor air quality.

“Harding Memo” Reveals Legal Liability Concerns

Another crucial document included in Tuesday’s release was what became known as the “Harding Memo,” a document sent to then-Deputy Mayor Robert Harding. It cited a Law Department estimate of about 35,000 potential plaintiffs — roughly 10,000 of whom were expected to file claims — as a result of the September 11 attacks, and outlined legislative options to limit the city’s legal liability.

“A major concern is that if these cases make it to court, the judges and juries will be biased in favor of plaintiffs (even though the City seems to have a strong defense) and therefore, award substantial damages to compensate individuals for their loss,” the memo states.

The memo also listed potential grounds for lawsuits against the city, including that “Health advisories caused individuals either to return to the area too soon (causing toxic exposure or emotional harm) or too late (causing economic hardship).”

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

When asked whether the yearslong delay in releasing the documents was a “cover-up,” the mayor said, “This was multiple mayoral administrations refusing to release documents that New Yorkers were owed.”

Jon Stewart and 9/11 Families Join Call for Accountability

Mamdani appeared alongside 9/11 families and Jon Stewart, a longtime advocate for increased transparency and resources for first responders and survivors.

“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. Everyone knew. Now it’s very clear that the city knew as well,” Stewart said.

Karen Klingon, who lost her brother after 9/11, attended the news conference Tuesday. Her brother, Robert Klingon, lived a five-minute walk from the World Trade Center when the towers came down and was treated through the World Trade Center Health Program, she told CNN. In 2018, he collapsed on the street and learned he had a brain tumor. He died two years later, Klingon said.

“I think there wasn’t just lack of transparency; there was a lack of regard for people, and I find that very disturbing,” Klingon told CNN. “Also, my brother was a lawyer and had a very acute sense of justice and injustice, and he would have certainly been appalled by the injustice of the lack of transparency and the lack of concern for people who are still suffering.”

Searchable Portal Launches for Public Access

A searchable portal will provide access to the documents, and the city is expected to add more material on a rolling basis in the coming months, officials said Tuesday. Every document published in the portal will be available for view and download at no cost.

The disclosure is expected to give the public a better understanding of how the city responded following the collapse of the World Trade Center as officials raced to restabilize Lower Manhattan and reopen the area. The documents were among 68 boxes stored in a city government office that were discovered last year and are being released ahead of Friday’s 25th anniversary of the attacks, according to city officials.