New York City officials released more than 170,000 pages of documents this week detailing air quality concerns and toxic exposures in Lower Manhattan following the September 11, 2001, terrorist attacks. The documents, which had remained hidden from public view for over two decades, reveal that hazardous substances—including carcinogens like benzene, asbestos, and dioxins—persisted around the World Trade Center site for months after the attacks, raising long-standing questions about the safety assurances previously made to residents and workers.

Mayor Zoharn Mamdani, speaking at a City Hall news conference Tuesday, accused earlier city leadership of misleading the public about the safety of breathing air in the aftermath of the collapse. "People got sick because the leaders they trusted lied and told them they were safe to breathe in toxic air," Mamdani said. The mayor chose not to specify which individuals he held responsible but noted that officials including then-Mayor Rudolph W. Giuliani and Environmental Protection Agency Administrator Christine Todd Whitman had publicly asserted that the air was safe.

The newly released records include audits, memos, and email correspondence among city, state, and federal agencies, highlighting debates about which substances to test for and how to communicate risks. For example, an October 2001 email from city health officials discussed removing certain compounds—such as mica, gypsum, and magnesium—from the list of air pollutants monitored, despite magnesium being recognized by the Centers for Disease Control and Prevention as a harmful component of World Trade Center dust.

One particularly significant hazard was dioxins, toxic compounds linked to cancer, which were detected months after the attacks. Officials expressed surprise at the persistently elevated levels, attributed in part to underground fires that continued burning at the site until December 2001. An email from the city’s Department of Environmental Protection noted concerns that dioxin contamination was lasting longer than expected and that benzene concentrations remained high at monitoring sites.

Asbestos levels were also documented in buildings up to a mile from ground zero. A November 2001 environmental assessment of an office building at 90 Church Street found asbestos throughout the debris and settled dust, along with other toxins including mercury. The report recommended removing all porous materials like carpeting and ceiling tiles to reduce exposure.

The release of the documents resolves a legal effort by the advocacy group 9/11 Health Watch, which had sought greater transparency on air quality issues after the attacks. The group’s attorney acknowledged that many victims who accepted federal compensation under the September 11th Victim Compensation Fund may be barred from suing the city due to legal immunity tied to the event’s classification as an act of war.

Experts who studied the environmental health impacts of the attacks emphasized the enduring risks posed by toxic exposures. Dr. Phillip Landrigan, a former professor of preventive medicine at Mount Sinai Hospital, explained that asbestos, though regulated by thresholds set by officials, carries no safe exposure level medically and can cause disease over time. He also highlighted pulverized cement dust as an immediate hazard responsible for respiratory ailments among rescue and recovery workers, describing the inhalation of the dust as akin to breathing a corrosive substance.

Among those joining Mayor Mamdani at the announcement was comedian and advocate Jon Stewart, who called attention to the ongoing struggle faced by survivors to have their illnesses acknowledged. Stewart remarked on the widespread awareness at the time that toxic dust and debris contaminated the environment, yet residents were repeatedly assured that the air was safe, a narrative he described as profoundly misleading.

City officials have pledged to review and release more documents over the coming year to provide fuller insight into the environmental health consequences of the September 11 attacks. The revelations underscore the complex and prolonged public health challenges stemming from the disaster, which continues to affect thousands of people two decades later.