A new longitudinal study published in JAMA Network Open has found a clear association between the severity of exposure at the World Trade Center (WTC) site and the incidence of lung cancer, more than a decade after the September 11, 2001, attacks.
The study followed 12,334 responders — including police officers, construction workers, firefighters, and volunteers — enrolled in the WTC Health Program on Long Island, New York, with a median age of 49.3 years at study entry. Over 135,009 person‑years of follow‑up, researchers documented 118 incident cases of lung cancer.
Using a novel activities-based exposure severity score, exposures were classified as mild, moderate, or severe. Incidence rates of lung cancer increased markedly with exposure severity:
- Mild exposure: 4.2 per 10,000 person‑years
- Moderate exposure: 12.7 per 10,000 person‑years
- Severe exposure: 21.0 per 10,000 person‑years
Compared with the mild exposure group, multivariable‑adjusted hazard ratios (AHRs) for lung cancer were significantly elevated:
- Moderate exposure: AHR 1.86 (95% CI, 1.19–2.91; p = 0.007)
- Severe exposure: AHR 2.90 (95% CI, 1.69–4.99; p < 0.001)
The researchers also identified specific risk factors within exposure types. Working for ≥500 hours in areas with strong odours of sewage, mould, or chemicals was associated with increased risk. Conversely, working off‑site or in cleaner environments and practising protective hygiene measures — such as changing clothes or wearing a hood suit — were associated with reduced lung cancer incidence.
Smoking remained the strongest overall risk factor, but associations with exposure severity persisted after adjusting for smoking status and pack‑years, as well as age, sex, education, and occupation.
Implications for practice
These findings underscore the importance of prolonged surveillance for responders exposed to complex disaster‑site environments, even decades after the event. They also highlight the need to integrate exposure severity and protective measures into occupational health strategies for first responders.
Paper: Clouston SAP, Meliker J, Mann FD, et al. Lung Cancer Incidence After September 11, 2001, Among World Trade Center Responders. JAMA Netw Open. 2025;8(10):e2536655. doi:10.1001/jamanetworkopen.2025.36655
