Firefighters face some of the most dangerous conditions in public service. While immediate threats like fire and smoke are obvious, cancer has become a growing occupational concern. A 2025 study in the International Journal of Epidemiology provides some of the clearest evidence to date of increased cancer mortality among U.S. firefighters.
Researchers analyzed data from the American Cancer Society’s Cancer Prevention Study-II, which followed over 470,000 men for 36 years (1982–2018). Within this large group, 3,085 were firefighters, and the study assessed how their cancer mortality compared to men in other professions.
Key Findings from the 36-Year Study
The analysis confirmed that occupational exposure as a firefighter is associated with elevated mortality for several cancers, with some risks persisting even after adjusting for potential confounding factors.
1. Skin Cancer Mortality
Firefighters had a 72% higher risk of death from skin cancer compared to other career professionals (HR 1.72; 95% CI: 1.14–2.60). This was the strongest association observed in the study and remained notable even when statistical adjustments were made.
2. Kidney Cancer Mortality
The study found a 39% higher risk of kidney cancer mortality (HR 1.39; 95% CI: 0.92–2.09). Although the confidence interval included 1.0, the trend suggested a potential link between firefighting and kidney cancer deaths.
3. Prostate and Colorectal Cancer
Researchers observed suggestive increases in mortality from prostate and colorectal cancers, particularly in participants who had more years of service as a firefighter. While these associations were weaker than for skin cancer, the pattern indicated a potential cumulative occupational effect.
4. Lung Cancer Over Time
An association with lung cancer mortality appeared only after three decades of follow-up. This delayed pattern underscores the long-term nature of the occupational risks identified in the study.
Even after adjusting for various factors and expanding the comparison to all non-firefighter occupations, the associations with skin and kidney cancer persisted, reinforcing the findings as meaningful signals of risk.
Expanding the Evidence Base
This research builds on the 2022 International Agency for Research on Cancer (IARC) evaluation, which classified firefighting as a cause of mesothelioma and bladder cancer. The 2025 study adds to this evidence by identifying elevated mortality from skin and kidney cancers and suggestive patterns in prostate, colorectal, and lung cancers over a 36-year follow-up period.
What This Means for Occupational Health
The study underscores that cancer risks for firefighters extend beyond the previously recognized types. Its population-based, long-term design strengthens the evidence base for firefighter health research and highlights the importance of continued surveillance and study of occupational exposures.
Reference
Teras LR, Diver WR, Mitchell EL, et al. Occupation as a firefighter and cancer mortality in a population-based cohort in the United States. Int J Epidemiol. 2025;54(4):dyaf104. doi: 10.1093/ije/dyaf104. PMID: 40721223
