Newly released documents reveal officials downplayed 9/11 air quality risks

Toxic air quality was recorded in Manhattan soon after the 9/11 attacks even as officials played down health risks to the public, according to a trove of newly released files.

Asbestos was found "nearly everywhere" they tested near Ground Zero, where the World Trade Center towers collapsed in 2001, New York City Mayor Zohran Mamdani said on Tuesday.

"People got sick because the leaders they trusted lied and told them they were safe to breathe in toxic air," he said, announcing the release of 170,000 documents related to the attacks.

Illnesses related to the dust and smoke from the collapse of the Twin Towers have claimed more lives than the attacks themselves, US health officials say.

Thousands of people have experienced health effects like cancer, including many who have died, after breathing in hazardous contaminants after the buildings' collapse.

Speaking alongside Mamdani at the news conference on Tuesday, television host and 9/11 survivor advocate Jon Stewart noted the newly released documents show the city did not realise that the air in Manhattan was toxic until October 2001.

"So to be fair to them, they only buried that information for 25 years," he said sarcastically.

The documents show asbestos was found near Ground Zero for months after the attacks at the same time people were being advised it was safe to go there.

The files, which include air-quality reports and communications among city officials, include October 2001 correspondence known as the "Harding Memo".

In it, an aide warned former Deputy Mayor Robert Harding that the city could face as many as 35,000 legal claims for its response to the attacks.

The document states that the city could be sued because health advisories caused individuals "to return to the area too soon (causing toxic exposure or emotional harm)".

City officials also told citizens to clean up dust and debris with "wet mops and rags" despite the presence of asbestos, which is only supposed to be cleaned by licensed professionals, according to another memo documenting the concerns of Congressman Jerry Nadler.

The memo pointed to testimony from the city's top health official at the time saying study had found "no elevated levels of asbestos in indoor air" but that tests showed dust had "low levels of asbestos in some samples".

The memo, attributed to Ester Fuchs, a special adviser at the time to Mayor Michael Bloomberg, acknowledged "potential problems for City Hall".

"Seemingly reputable scientists have come down on both sides of the argument," the memo states. "However, If Nadler's concerns are justified, we are not informing people of the real health risks in lower Manhattan, the City may face major public relations problems and is leaving Itself open to a barrage of lawsuits."

Days after the attack, city and federal officials - including the US Environmental Protection Agency (EPA) - declared that the air near the Twin Towers was safe, though research suggests people were breathing in toxic chemicals.

Christine Todd Whitman, the head of the EPA at the time, later apologised for this declaration, saying the agency "did the very best we could at the time with the knowledge we had".

"There's a lot of research, probably, that can be done about what was in the air, and the kind of illnesses that derived of those toxins that were in the air, like what happened to my brother," she said. "Hopefully it helps people that were sick know and in the future."

Phil Alvarez, whose brother Luis Alvarez died of cancer in 2019 after exposure to Ground Zero toxins, told the BBC that people "continue to get sick every single day, continue to die".

He also hopes the documents will help New Yorkers understand the true risk of exposure.

"Whether you were the janitor down there or whether you were the mayor down there," he told the BBC, "you deserve to have that information".