WASHINGTON, D.C. — Twenty-five years after the Sept. 11 terrorist attacks, long-term monitoring of more than 154,000 World Trade Center responders and survivors is showing higher cancer-screening rates and lower mortality among some enrolled patients even as chronic physical and mental health conditions continue to emerge, according to a paper published in JAMA.
The analysis by World Trade Center Health Program staff found that disaster-related illnesses can persist or emerge decades after exposure, often affecting multiple organ systems and requiring sustained monitoring and coordinated care.
The program, administered by the Centers for Disease Control and Prevention’s National Institute for Occupational Safety and Health, has provided medical monitoring and treatment for covered 9/11-related conditions since 2011. Eligible responders and survivors receive that care without out-of-pocket costs.
Enrollment exceeded 154,000 as of June, with membership increasing by a median of more than 6,500 people annually since 2012. The population is also aging: enrolled members had a median age of 39 at the time of the attacks and 63 in 2025.
Cancer, respiratory disease, gastroesophageal reflux disease and mental disorders are among the most prevalent conditions affecting members. Some illnesses can appear years after exposure, reinforcing the need for continued surveillance, according to the authors.
Individuals directly exposed to the attacks have a higher prevalence of chronic conditions and poorer health-related quality of life than the general population. Multimorbidity has also contributed to greater disability, more complex treatment and higher health care utilization and costs.
At the same time, several measures indicate stronger preventive-care performance among program members.
About 54% of eligible members meeting U.S. Preventive Services Task Force criteria received lung cancer screening in 2024, compared with an 18% actual U.S. screening rate in 2022 and a 7.5% national benchmark cited by the authors.
Program research also found responders with cancer who participated in the WTC Health Program experienced mortality rates 26% to 64% lower than the New York State general population across prostate, lung, kidney and colorectal cancers.
The authors cautioned that better survival could partly reflect lead-time bias from cancer screening. Enrolled responders also have relatively low smoking rates, another factor that could contribute to mortality differences.
Smoking prevalence among program members was about 4% in 2025, compared with 9.1% among U.S. adults.
The results nevertheless suggest that medical monitoring, earlier detection and coordinated treatment with case management may improve outcomes for a population carrying elevated health risks from disaster-related exposures.
“By linking surveillance, clinical care, and research, the Program functions as a continuous learning model that informs clinical practice and advances understanding of the long-term effects of 9/11 exposures among an aging population,” John Howard, director of NIOSH and administrator of the WTC Health Program, stated.
The program also reported high levels of guideline-concordant asthma management, with most members maintaining an appropriate balance between controller and rescue medications. Emergency treatment for acute exacerbations was uncommon, while hospital readmissions remained in line with expected levels for a medically complex population.
Long-term psychological effects remain significant.
Research has linked 9/11 exposure to persistent post-traumatic stress disorder, major depression, anxiety and substance-use disorders. Those conditions remain prevalent decades later despite access to treatment.
The program expanded mental-health services through telehealth, particularly during the Covid-19 pandemic. Telehealth visits increased 363% from early 2020 through late 2021, rising from 41 to 190 visits per 1,000 person-quarters before later stabilizing.
Clinical understanding of 9/11-related disease has also changed over time. The program has expanded covered conditions to include all cancers, new-onset chronic obstructive pulmonary disease and acute traumatic injuries as research established links with exposure.
About one-third of members have no known 9/11-related health effects.
The program generally requires strong evidence from peer-reviewed epidemiological studies before adding a condition for coverage. It continues to evaluate research involving conditions including ischemic heart disease, stroke and dementia, which are not currently covered as 9/11-related illnesses.
Research has also influenced clinical recognition of other conditions. One study found that people with high World Trade Center exposure had twice the risk of severe obstructive sleep apnea, contributing to greater recognition of the disorder among exposed populations.
The aging membership is creating new operational pressures. Many members now have multiple chronic illnesses, requiring greater coordination among specialists, long-term medication management and attention to physical, cognitive and sensory impairment.
The program is also expected to become increasingly dominated by survivors rather than responders, with members more widely dispersed outside the New York metropolitan area.
Participation in annual monitoring examinations among members using the Nationwide Provider Network needs to increase, according to the authors, as do research-consent rates to expand the pool of eligible study participants.
Telemedicine use is lower among members outside the New York region, and state medical-licensing requirements can complicate continuity of care when patients relocate while seeking to remain with established New York providers.
The authors described those constraints as evidence that long-term disaster health programs require continuing adjustments in staffing, resources and policy as exposed populations age and move.
The broader lesson from 25 years of follow-up is that major environmental and occupational exposures may generate health consequences for decades, making sustained surveillance, clinical care and research part of disaster response rather than only its immediate aftermath.
The paper, “Twenty-Five Years After 9/11 — Lessons from the World Trade Center Health Program,” was published online Sept. 10. Additional information about the program and its research is available at www.cdc.gov/wtc/research.
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