Who knew what about 9/11 toxic air? City Council wants answers, study.

The New York City Council plans to seek to fund the completion of a long-delayed study aimed at investigating who knew what about lower Manhattan’s toxic air unleashed in the aftermath of the 9/11 terrorist attacks.

Julie Menin, the council speaker — who at the time lived and worked near Ground Zero — now wants to add an additional $4.5 million to the budget of the city’s Department of Investigation so the agency can comply with a resolution passed last year directing the local government to undertake the study, according to her spokesman Jack Lobel.

The budget, which is negotiated between the council and the mayor, is due at the end of the month. It is expected to be just under $130 billion.

So far, the 9/11 study, which is due by July 2027, is incomplete, a status quo that Menin and her colleague Councilwoman Gale Brewer are highlighting with the demand for the increased funding.

"Thousands of families, including my own, are still waiting for answers about what the city knew about the environmental toxins that sickened or killed our loved ones after 9/11," according to a statement from Menin, whose mother died of a 9/11-related cancer.

Advocates for those sickened by the toxic air  in the vicinity of Ground Zero in the months after 9/11 have pressed mayors going back to Rudy Giuliani, and his four successors, to disclose what officials knew.

It was just days after the 9/11 attacks that the city health department announced that the public’s risk of both short- and long-term adverse health effects related to asbestos exposure from the attacks was "very low." And, the following month, the then-health commissioner said tests of particulate matter in the air didn’t pose a long-term health risk to the public.

The federal government also reassured the public.

Those public declarations proved to be false.

According to the Centers for Disease Control and Prevention, of about 400,000 people who were exposed, 80,000 have been sickened. Among them: Giuliani himself.

Brewer, who represents parts of Manhattan’s Upper West Side, said she hopes that the disclosure might help those who are stricken.

"Early analysis of the toxins that engulfed lower Manhattan and northern Brooklyn could lead to medical breakthroughs for those still struggling with 9/11 illnesses and any further delay is unconscionable," Brewer said in a statement.

So far, only the city’s Department of Environmental Protection has submitted its report.

Officials from the Department of Investigation are to appear Tuesday at the council’s Oversight and Investigations Executive Budget hearing, where the 9/11 issue is expected to come up.

Mayor Zohran Mamdani’s press office did not immediately return a message seeking comment.

By Matthew Chayes

matthew.chayes@newsday.comchayesmatthew

Matthew Chayes, a Newsday reporter since 2007, covers New York City.