NYC releases 170,000 pages of post-9/11 air quality documents showing city knew of toxic risks

On Tuesday, New York City opened a digital archive containing more than 170,000 pages of government documents that tell a story officials have long resisted telling: that city leaders knew the air around Ground Zero was poisoned, and they said nothing.

The records span multiple city agencies and cover the months following the September 11 attacks. They include air quality reports, contamination surveys, internal correspondence, and health assessments—the paper trail of what happened when thousands of people breathed in dust and debris while their government assured them they were safe. Mayor Zohran Mamdani announced the release at a news conference alongside 9/11 health advocates, including comedian Jon Stewart, framing the move as an overdue reckoning. "These are documents that show what the city knew about the toxic air around Ground Zero, when they knew it, and how they acted to limit liability," Mamdani said.

The documents reveal a persistent gap between private knowledge and public messaging. Health officials continued finding evidence of asbestos in the area at least ten months after the attacks—long after city officials had repeatedly told New Yorkers the air was safe to breathe. The records include multiple asbestos reports, some showing levels below regulatory thresholds, others indicating higher concentrations, though many lack written analysis of what the numbers meant. Stewart, speaking at the release, was direct about what the papers demonstrate: "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. And now it's very clear that the city knew as well."

One document has already become central to the accountability conversation. The Harding Memo, written just weeks after the attacks, discussed the possibility of lawsuits from people claiming exposure to toxic air. According to New York Representative Jerry Nadler, the memo shows that government officials under former Mayor Rudy Giuliani predicted thousands of New Yorkers would face devastating health effects. "The failure of government officials to share this information with the public and adequately respond to the dangers has had devastating and, in too many cases, fatal consequences," Nadler said. The memo's existence suggests officials anticipated the harm before it materialized—and chose not to warn the public.

The release comes after a multiyear legal battle. Mamdani announced the settlement of two lawsuits brought by 9/11 Health Watch, ending years of litigation over access to these very records. The city has also committed to appointing staff to help eligible New Yorkers use the documents as proof of their presence in the exposure zone, which can unlock access to federal health programs. Attorney Matthew McCauley noted that many people already qualify—those who lived downtown, those caught in the dust cloud, and those who had no way of knowing they were in danger.

Former Mayor Eric Adams's office issued a statement saying any post-9/11 air quality documents should be released and scrutinized, but that Adams did not create, conceal, or control records from prior administrations. CBS News reached out to former Mayors Rudy Giuliani, Michael Bloomberg, and Bill de Blasio for comment and received no response. The city has indicated that more documents will be added to the portal on a rolling basis, suggesting this archive is not yet complete. What remains to be seen is whether access to these records will finally allow thousands of New Yorkers to connect their illnesses to the exposure they endured, and whether accountability—long delayed—can still matter.