The September 11 attacks continue to affect the health of people who were exposed to the World Trade Center disaster. A quarter-century later, doctors and researchers are paying increasing attention to cancer among survivors, particularly diseases that can remain hidden for many years before symptoms appear.
The growing number of September 11 cancer diagnoses has renewed questions about what the toxic environment around Ground Zero may mean for survivors as they get older.
Exposure Extended Beyond First Responders
The health impact of September 11 was not confined to firefighters, police officers and other emergency workers who rushed toward the disaster.
Dust from the collapsed towers spread throughout Lower Manhattan. It entered buildings and settled on indoor surfaces, while people nearby breathed air containing particles from destroyed construction materials, burning jet fuel and heavy metals.
The CDC has estimated that up to 400,000 people were exposed to the contamination. Residents, employees and students were among those who remained in or returned to areas affected by the dust.
More Survivors Are Being Treated for Cancer
The World Trade Center Health Program has recorded a significant rise in cancer among survivors. Approximately 54,000 survivors qualify for financial assistance through the program, and about half have been diagnosed with cancer.
That represents roughly three times the number reported five years earlier.
The increase comes as the people exposed in 2001 reach older ages, when cancer naturally becomes more common. Researchers, however, are examining whether some of the illnesses are also connected to the unusual mixture of contaminants released after the towers collapsed.
The rise in September 11 cancer diagnoses has made that research increasingly important.
Why Asbestos Is a Major Concern
One area receiving particular attention is mesothelioma, a rare and aggressive cancer associated with asbestos exposure.
Asbestos was used in parts of the World Trade Center complex, and researchers have continued examining the potential effects of exposure among people who were near the site.
Mesothelioma is especially significant because it can take decades to develop. Researchers studying World Trade Center survivors have identified cases at rates that appear higher than those seen in the broader population.
Its long latency period is one reason scientists are concerned that additional cases could emerge in the years ahead.
New Patients Are Still Entering the Program
Medical facilities serving people affected by September 11 continue to see new patients. One New York center reports approximately 120 new patients every month.
There has also been a change in who is enrolling for assistance. Early in the program’s history, first responders accounted for more new enrollments than survivors. In recent years, that pattern has changed.
CDC data show that roughly twice as many survivors as first responders enrolled in the program during 2024 and 2025. Some people who were exposed may not have known that they could qualify for assistance.
The Long-Term Picture Is Still Developing
The continuing increase in September 11 cancer diagnoses demonstrates that the health effects of the attacks are still being studied 25 years later.
The World Trade Center Health Program currently serves nearly 150,000 members living across all 50 states and US territories, providing monitoring and treatment for health conditions connected to the attacks.
For researchers, the coming years will be important as survivors continue to age and more time passes since the original exposure. The medical data being collected today could help determine the longer-term pattern of illnesses associated with the disaster.
