New York City has just released over 170,000 pages of previously undisclosed records about the air quality following the September 11, 2001, attacks, and they show that city officials at the time were fully aware that conditions around Ground Zero were unsafe to breathe, despite repeatedly telling the public otherwise. Mayor Zohran Mamdani announced the massive release at a news conference on Tuesday, CNN reported. He stated, “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.” He highlighted a somber statistic, noting that “Now, close to 25 years later, more people have died from 9/11-related illnesses than were killed on the day itself.” The records are coming out ahead of Friday’s 25th anniversary of the attacks, and they aim to give us a much clearer picture of how the city responded after the World Trade Center collapsed. Officials had been scrambling to restabilize Lower Manhattan and get the area reopened. These documents were actually found last year among 68 boxes stored in a city government office This release is also the result of a lawsuit from the advocacy group 9/11 Health Watch Ben Chevat, the executive director of 9/11 Health Watch, spoke at the news conference, thanking the mayor. “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. He believes these documents will be vital for people to access federal assistance and kick-start further research into health outcomes. .@NYCMayor Mamdani (D) announces the release of 9/11 records related to air quality: "These are documents that show what the city knew about the air around Ground Zero, when they knew it, and how they acted to limit liability." pic.twitter.com/gL14Zx1pn7— CSPAN (@cspan) September 8, 2026 The documents, while only a fraction of all the air quality reports, include some pretty damning internal memos. One particularly notable one is the “Harding Memo,” which was sent to then-Deputy Mayor Robert Harding. This memo cited a Law Department estimate of around 35,000 potential plaintiffs, with about 10,000 expected to file claims, all stemming from the September 11 attacks. It even outlined legislative options to limit the city’s legal liability. The memo clearly showed concern about potential legal battles. It stated, “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.” It also listed potential grounds for lawsuits, 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).” Mayor Mamdani didn’t mince words, saying, “People got sick because the leaders they trusted lied and told them they were safe to breathe in toxic air.” When he was asked if the years-long delay in releasing these documents amounted to a “cover-up,” Mamdani responded, “This was multiple mayoral administrations refusing to release documents that New Yorkers were owed.” It’s important to remember the scale of this tragedy. Nearly 3,000 people died on 9/11 itself, but thousands more, including first responders who spent months at the site, have since died from 9/11-related cancers and other illnesses. At least 140,000 people from all 50 states have enrolled in the World Trade Center Health Program, and a staggering 49,000 have been diagnosed with certified WTC-related cancers, according to the 9/11 Memorial. Mamdani also noted that even more people are eligible for assistance than are currently enrolled, including residents who lived near the site but haven’t been reached, and those living outside of New York. Cancer wasn’t covered when Congress first created the health program in 2011; it was only added in 2012 after a tough fight from advocates and a study showing elevated cancer rates among New York firefighters. The city is making these documents accessible through a searchable portal, and officials said Tuesday that more material will be added on a rolling basis in the coming months. Every document in the portal will be free to view and download.