The Dust That Never Settled: 9/11 and Asbestos and other Dust-related Illness in New York
(Written by myself aided by in part by AI)
When the Twin Towers collapsed on September 11, 2001, they released an estimated one million tons of pulverised building material across Lower Manhattan and parts of Brooklyn.
That cloud wasn't just concrete dust — it carried a mixture of glass fibres, heavy metals, and asbestos, which had been used as fireproofing in sections of the towers built before the material's use was restricted in the early 1970s.
A quarter of a century later, that single morning is still generating new diagnoses of asbestos-related disease among responders and residents alike.
How much asbestos was in the dust?
An estimated 400,000 to 500,000 residents, first responders, victims, rescue and clean crews, and others were exposed to the dust after 2 million tons of debris piled on top of ground zero. It took about 100 days for fires to be extinguished, and even longer for the dust cloud to completely settle.
Early EPA sampling in Lower Manhattan told a mixed story. Of 136 dust samples analysed, 34 — roughly a quarter — showed asbestos concentrations above 1%, a threshold US regulators use as a marker of concern.
Air and dust testing elsewhere, such as at the Staten Island landfill where WTC debris was taken, generally came back below that level, though officials acknowledged the true asbestos content of the towers could only be estimated because original building plans were hard to access.
The inconsistency of these readings — combined with the sheer scale of the dust cloud, which reached roughly 1,500 metres into the air — fueled years of concern that exposure had been both widespread and undercounted.
Tracking the health fallout
In response, Congress established the World Trade Center (WTC) Health Program through the James Zadroga 9/11 Health and Compensation Act of 2010, creating a federally funded system to monitor and treat conditions tied to 9/11 exposure.
The program now serves an estimated pool of over 400,000 people believed to have been affected, whether as emergency responders or as residents, workers, and students in the disaster area.
As of mid-2025, close to 140,000 people are enrolled — more than 86,000 responders and nearly 51,000 survivors. A large share have at least one certified WTC-related condition, with respiratory illness, gastroesophageal reflux, various cancers, asthma, sleep apnea, and PTSD among the most common diagnoses.
Asbestos-specific disease: rare, but confirmed
Mesothelioma — a cancer of the lining of the lungs or abdomen that is caused almost exclusively by asbestos exposure and can take decades to appear — is one of the clearest markers researchers look for when tracing asbestos's health legacy.
A 2024 case review from the WTC Environmental Health Center identified four mesothelioma diagnoses among enrolled community survivors as of mid-2023: two pleural (lung lining) and two peritoneal (abdominal lining) cases.
Researchers noted this was an early accounting, since mesothelioma's long latency period means additional cases tied to 9/11 exposure are still expected to surface in the coming years.
Beyond mesothelioma, a broader pattern of chronic respiratory and fibrotic lung disease has shown up in exposure studies. Reviews of the WTC Health Registry cohort have documented cases of pulmonary fibrosis — permanent lung scarring — among responders, alongside much more common but still serious conditions like chronic cough, wheezing, and shortness of breath, which were strongly associated with heavy dust exposure and dust-cleanup behaviour (such as dry sweeping without water) in the months after the attack.
Separately, a review of nearly 3,000 cancer diagnoses among WTC Environmental Health Center patients found dozens of rare cancer types, mesothelioma among them, layered on top of more expected increases in cancers like thyroid and prostate cancer.
Beyond asbestos: other toxic dusts and their toll
Asbestos was only one strand of what one Mount Sinai physician has called a "witches' brew" of contaminants in the WTC dust cloud. Alongside it, the pulverised debris contained pulverised cement (highly alkaline, with a pH of 11–12), silica, glass fibres, lead and other heavy metals, polychlorinated biphenyls, polycyclic aromatic hydrocarbons from the fires that burned for months afterwards, and even carbon nanotubes later identified in both dust samples and the lung tissue of exposed responders. Many of these have driven fatal or life-shortening disease in their own right, separately from any asbestos-specific diagnosis.
The clearest early death linked to this broader dust mixture was that of retired NYPD detective James Zadroga, whose 2006 death — attributed by officials to a severe respiratory illness sometimes described as "black lung disease," along with mercury exposure affecting the brain, following months of work at Ground Zero — became the namesake for the 2010 US legislation that created today's WTC Health Program. He is widely regarded as the first emergency responder whose death was formally linked to WTC dust and debris exposure.
Chronic obstructive pulmonary disease (COPD) and a related condition called asthma-COPD overlap (ACO) have since been documented as a persistent, and sometimes fatal, legacy of that non-asbestos dust burden.
A WTC Health Registry study of more than 17,000 responders found that those who arrived at the site within the first 48 hours — when dust concentrations were at their highest — had a 34% higher risk of developing COPD and a 55% higher risk of developing ACO than later arrivals, with prior asthma and smoking history compounding the risk further.
The same fine particulate matter, combustion by-products, and metals have also been tied to elevated cardiovascular disease among responders, with reviews of the WTC-exposed firefighter and recovery-worker population describing lasting cardiopulmonary and neurological harm from the dust's chemical mixture, separate from its asbestos content.
Overall, cancers linked to the full range of WTC contaminants — not asbestos alone — account for the largest single share of the more than 580 confirmed 9/11-related deaths recorded by 2018, and for the bulk of the 343 FDNY deaths from WTC-related illness recorded by 2023.
The death toll
Deaths tied to 9/11-linked illness — asbestos-related and otherwise — have been mounting for years, and by several measures now exceed the death toll of the attack itself.
Nearly 3,000 people were killed in the immediate attacks on the World Trade Center, the Pentagon, and Flight 93.
By 2021, the federally administered September 11th Victim Compensation Fund reported that it had processed close to 3,900 claims filed on behalf of people who died of a 9/11-related illness — a total that, as the fund's administrator noted publicly, had already surpassed the number of people who died on the day itself.
Cancer accounts for a large share of that toll. As of September 2018, CDC data showed more than 580 people — responders, survivors, and Lower Manhattan residents — had died of 9/11-related cancers, out of nearly 10,000 people who had been diagnosed with such cancers by that point. Fifteen New York police officers alone died of 9/11-linked cancers in 2018, a four-fold jump from the year before.
Among New York City firefighters specifically, the toll has now caught up with the death count from the attack itself: as of September 2023, 343 current and retired FDNY members — firefighters, paramedics, and civilian staff — had died from WTC-related illnesses since 9/11, matching the 343 FDNY members killed on the day of the attacks. That list continues to grow each year, with cancer and pulmonary fibrosis (a form of lung scarring linked to asbestos and dust exposure) among the recorded causes.
Program-wide, the WTC Health Program's own membership statistics put the scale in context: of roughly 127,000 total enrolled members as of September 2023, 6,578 were recorded as deceased.
That figure covers all causes of death, not only WTC-certified conditions, but it reflects the aging and declining health of a population that was, on average, in early-to-mid adulthood at the time of exposure.
Mesothelioma deaths specifically remain a small but expected-to-grow slice of this total. Because the cancer can take 20 to 50 years to develop after asbestos exposure, only a handful of confirmed mesothelioma cases — four, as of the most recent WTC Environmental Health Center case series — have been identified among community survivors so far, and researchers explicitly caution that this is an early count rather than a final one, given how many more members are still moving through the relevant latency window.
Some estimates state that at the peak, this figure could rise to around 16,000 fatalities a year in the years to come.
Why the numbers are still climbing
Asbestos disease is unusual in that it can take 20 to 50 years to manifest after exposure. That means the full toll of 9/11-linked asbestos illness is, by design, not yet fully known — physicians and epidemiologists expect the current small cluster of confirmed mesothelioma cases to grow as more of the exposed population reaches the relevant latency window.
The WTC Health Program was extended by Congress in 2015 to provide coverage through 2090, a deliberate acknowledgement that the health consequences of that single morning will likely continue to surface for the rest of the affected generation's lifetime.
Sources: CDC/NIOSH World Trade Center Health Program program summaries and statistics (cdc.gov/wtc ); EPA WTC dust sampling data; Yilmaz et al., "Mesothelioma Cases in the World Trade Center Survivors," Ann Case Rep, 2024; WTC Health Registry pulmonary fibrosis cohort study; WTC Environmental Health Center cancer characteristics studies; September 11th Victim Compensation Fund reporting (2021); FDNY/Uniformed Firefighters Association memorial statistics (2023); CBS News/CDC reporting on 2018 cancer death figures. Information also taken from the Lung Cancer Centre website, and from the KSH Safety Services podcast, Safety is My Middle Name, https://open.spotify.com/episode/3SRjwaLCCK8Lhvw1yxs02l Series2 Episode 2 with Mark Smith.
