NEW YORK (BLOOMBERG) -- Mayor Zohran Mamdani released more than 170,000 pages of records about the aftermath of the Sept. 11, 2001, attacks, including documents showing officials were weighing potential liability from toxic exposure while trying to reassure the public about the safety of Lower Manhattan.
The collapse of the World Trade Center’s twin towers in the attacks created massive dust clouds that enveloped much of downtown, covering highly populated neighborhoods with ash, debris and harmful particles, according to the US Centers for Disease Control and Prevention. Fires in the towers’ debris piles burned for months after the attacks, releasing carcinogenic byproducts.
One memo prepared in October 2001 for Robert Harding, a deputy mayor under Rudy Guiliani, estimated that the city could face 35,000 potential plaintiffs and contemplated seeking federal protection from “toxic tort cases that might arise in the next few decades.”
Another city document from May 2002 said that officials would avoid using the word “risk” in correspondence about a cleanup program because doing so “would defeat the purpose of creating public confidence.”
https://t.co/xo8PaNzlap
Mayor Mamdani Holds Press Conference to Make a 9/11-Related Announcement
— Mayor Zohran Kwame Mamdani (@NYCMayor) September 8, 2026
An estimated 400,000 people, including first responders, were exposed to toxic contaminants and other hazards in the days, weeks and months following the attacks, according to the CDC.
The records were made public Tuesday, days before the 25th anniversary of the attacks, as the city settled two lawsuits brought by 9/11 Health Watch over documents concerning air quality and health risks. The initial release includes the so-called Harding Memo and records from 68 boxes that city officials said weren’t located until 2025 despite repeated public-records requests.
“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. He said the records also show asbestos, a known human carcinogen, was found “nearly everywhere that inspectors tested.”
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