What Percentage of Firefighters Get Cancer? The Numbers Every Chief Should Know

by Heidi Enders | Jul 27, 2026 | Firefighter Health

Ask ten firefighters what percentage of them will get cancer, and someone will say 68 percent. It gets repeated at trainings, in union halls, and across social media. It is also not what the research says. The real numbers are serious enough on their own, and as a chief, you deserve the accurate version rather than the viral one. Here is what the largest studies actually found, why the job itself is now classified alongside tobacco as a known carcinogen, and what both mean for how you protect your crew.

DISCLAIMER: This is general information, not legal advice. NDS Wellness is a healthcare provider, not a law firm. Whether any specific obligation applies to your workforce depends on your industry, exposures, and jurisdiction, and should be confirmed with your safety team and employment counsel.

Key Insights

The “68 percent” figure is a misread of the data: No credible study shows that two-thirds of firefighters get cancer. That number misrepresents the research, and the Firefighter Cancer Support Network has publicly corrected it.
Firefighters face a 9 percent higher cancer diagnosis rate: The landmark NIOSH study of nearly 30,000 career firefighters found a 9 percent higher rate of cancer diagnoses and a 14 percent higher rate of cancer deaths than the general US population.
The job is now a Group 1 carcinogen: In 2022, the World Health Organization’s cancer agency reclassified firefighting as “carcinogenic to humans,” the same evidence tier as tobacco and benzene.
Cancer is the leading line-of-duty killer: The IAFF reports that cancer caused roughly two-thirds of career firefighter line-of-duty deaths between 2002 and 2019.
Early detection is the lever you control: You cannot remove every carcinogen from the job, but regular, on-site screening helps catch cancer at the stage when it is most treatable.

So, What Percentage of Firefighters Get Cancer?

There is no single, clean percentage, and any source that hands you one precise number is oversimplifying. What the research consistently shows is a meaningfully elevated risk, not a coin flip.

Where the “68 Percent” Myth Comes From

The claim that 68 percent of firefighters will get cancer has circulated for years. The Firefighter Cancer Support Network, one of the most trusted voices in the fire service, has directly addressed it and describes it as a misrepresentation of the underlying data. The studies never concluded that most firefighters get cancer. They concluded that firefighters get cancer at higher rates than the public, which is a different and more precise claim.

What the Research Actually Measures

Cancer studies rarely report that a set percentage of a group will get cancer. Instead, they compare how often a group is diagnosed against how often you would expect based on the general population. That comparison is where the real firefighter numbers live, and they are concerning enough without exaggeration.

The NIOSH Study: 9 Percent More Diagnoses, 14 Percent More Deaths

The most authoritative data comes from a multi-year study led by the National Institute for Occupational Safety and Health (NIOSH), the federal agency responsible for worker safety research.

The Largest US Firefighter Cancer Study to Date

Between 2010 and 2015, NIOSH, working with the National Cancer Institute and the University of California, Davis, studied nearly 30,000 career firefighters from Chicago, Philadelphia, and San Francisco who served at any time between 1950 and 2009. It remains the largest study of its kind in the United States.

The Headline Findings

Compared with the general US population, the firefighters in the study had a 9 percent higher rate of cancer diagnoses and a 14 percent higher rate of dying from cancer. The increases were driven mainly by cancers of the respiratory, digestive, and urinary systems. NIOSH itself has noted that some media coverage overstated these findings, which is exactly why the accurate numbers matter.

The Cancers That Show Up Most

The elevated risk is not spread evenly. Certain cancers appear far more often in firefighters, and knowing which ones shapes what a screening program should actually look for.

Mesothelioma and Asbestos-Linked Cancers

The NIOSH study was the first to identify an excess of mesothelioma in US firefighters, at roughly twice the rate of the general population. Researchers linked the finding to asbestos exposure in older burning structures.

Digestive, Urinary, and Reproductive Cancers

Firefighters in the research showed a higher risk of esophageal cancer, roughly 62 percent higher for diagnosis according to NIOSH data, and earlier meta-analysis found about a two-fold excess of testicular cancer. Researchers also observed excess bladder and prostate cancers appearing at younger ages than usual.

Why the Job Itself Is Now a Known Carcinogen

In 2022, the science reached a turning point that every chief should understand.

The IARC Group 1 Classification

The International Agency for Research on Cancer (IARC), the cancer arm of the World Health Organization, reclassified occupational exposure as a firefighter as “carcinogenic to humans,” its highest category (Group 1). That places the job in the same evidence tier as tobacco smoking and benzene. The classification was based on sufficient evidence linking the work to mesothelioma and bladder cancer, with more limited evidence for several other cancers.

What Group 1 Does and Does Not Mean

Here is an important nuance the American Cancer Society points out. A Group 1 classification means there is strong evidence that the exposure can cause cancer. It does not, by itself, say how large that risk is for any one person. In plain terms, the science is now settled that the job carries a real cancer risk, even though the size of that risk varies by individual, role, and years on the line.

Cancer Is the Leading Line-of-Duty Killer

The clearest picture of the human cost comes from line-of-duty death data. The International Association of Fire Fighters (IAFF) reports that cancer caused roughly two-thirds of career firefighter line-of-duty deaths between 2002 and 2019. For the modern fire service, cancer has quietly become a larger threat than the fires themselves.

What Chiefs Can Actually Do About It

You cannot eliminate carcinogen exposure from firefighting. Detection timing, however, is something a department can control, and it changes outcomes.

The Case for Regular Screening

Most of the cancers driving firefighter risk are far more survivable when caught early. That is the entire argument for routine, comprehensive screening built around firefighter-specific risks, rather than a standard annual physical that was never designed with this exposure profile in mind.

Removing the Barriers to Getting Screened

The screening that gets skipped is the one that requires a day off and a drive across town. Bringing screening to the station, across every shift, is the most reliable way to make sure the whole crew actually gets checked, not just the members who happen to have time.

How NDS Wellness Screens Firefighters for Cancer

NDS Wellness was built to close exactly this gap. Our firefighter cancer screening program brings physician-led screening directly to your station, on every shift. Each firefighter gets a real appointment, not a finger-prick at a folding table, including comprehensive blood work and cancer screening tuned to the risks the research above identifies.

Results are explained by a physician, and follow-up care is coordinated, so a concerning finding becomes a clear next step rather than a dead end. Because we arrive in a mobile wellness clinic, your department can screen the whole crew without pulling anyone off shift. It is one part of our broader firefighter health and wellness program, which also aligns station exams with NFPA standards.

Sources

National Institute for Occupational Safety and Health (NIOSH), Firefighter Cancer Study findings, CDC: cdc.gov/niosh/bulletin/2017/firefighter-cancer.html
International Agency for Research on Cancer (IARC) / World Health Organization, “Carcinogenicity of occupational exposure as a firefighter,” The Lancet Oncology, 2022
NIOSH, National Firefighter Registry (NFR) for Cancer, CDC: cdc.gov/niosh/firefighters/registry/index.html and NFR Protocol: NFR Protocol (2025)
“Distinct Prostate Cancer Survival Outcomes in Firefighters: A Population-Based Study,” Florida cancer registry analysis: ncbi.nlm.nih.gov/pmc/articles/PMC11010940/
Firefighter Cancer Support Network, FAQ (summarizing LeMasters 2006 meta-analysis, Daniels NIOSH phase 2, and Pukkala Nordic study): firefightercancersupport.org/resources/faq
American Cancer Society, “Firefighting and Cancer Risk”: cancer.org/cancer/risk-prevention/chemicals/firefighting.html

Frequently asked questions

How does sleep deprivation affect health?

Chronic sleep loss disrupts the overnight fall in blood pressure that gives the cardiovascular system daily recovery, impairs glucose processing, and affects inflammatory markers. Over time these contribute to sustained hypertension and elevated metabolic risk rather than simply causing tiredness.

How common are sleep disorders among police officers?

A study of nearly 5,000 police officers published in JAMA found 40.4 percent screened positive for at least one sleep disorder, with the majority previously undiagnosed. Obstructive sleep apnea was most common at 33.6 percent screening positive.

What is obstructive sleep apnea?

Obstructive sleep apnea is a condition where breathing repeatedly stops and restarts during sleep, producing cycles of oxygen desaturation that strain the cardiovascular system. Untreated, it is associated with hypertension, arrhythmia, and elevated cardiovascular risk, and it is highly treatable once identified.

Why do police officers sleep poorly?

Rotating and overnight shifts prevent the body from adapting to any consistent pattern, and daytime sleep conflicts with the internal clock signaling wakefulness. Research on officers working twelve hour rosters found poor sleep quality in 69 percent of the sample.

Does poor sleep raise blood pressure?

Blood pressure normally falls during sleep, and chronic disruption of that pattern contributes to sustained elevation. Research on shift working officers found blood pressure and fatigue levels strongly related after accounting for age, waist to hip ratio, and lifestyle factors.

Can sleep problems affect blood sugar?

Yes. Insulin sensitivity is affected by both sleep duration and circadian alignment, and sleep restriction has been associated with impaired glucose tolerance. This is one mechanism connecting shift work and poor sleep to elevated metabolic risk in officers.

How would an officer know they have a sleep disorder?

Often they would not. Sleep apnea occurs during sleep, so the noticeable symptoms are daytime fatigue and poor rest quality, which officers typically attribute to their schedule. This is why most cases in the JAMA study were previously undiagnosed.

Are sleep disorders treatable?

Obstructive sleep apnea in particular responds well to treatment once diagnosed. The main obstacle is detection rather than available care, which is why raising sleep during a medical evaluation matters.

Does health screening test for sleep disorders?

Screening does not measure sleep directly, but it identifies the cardiovascular and metabolic effects of chronic sleep disruption, including elevated blood pressure and abnormal glucose. A physician reviewing those findings can discuss sleep and refer for proper evaluation when warranted.

Can NDS screen officers on night shift?

Yes. We bring a mobile wellness clinic on-site and screen across every watch, including overnight, so officers are evaluated during working hours rather than during their sleep period. This substantially raises participation among the officers most affected.

Stop Treating Poor Sleep as Part of the Job

Chronic sleep loss has measurable cardiovascular and metabolic consequences, and a large share of officers carry treatable sleep disorders without knowing it. NDS Wellness brings physician-led screening to your department on every watch.

Heidi Enders

Director of Corporate Services @ NDS Wellness

Heidi Enders is passionate about making preventative care easy to reach. As Director of Corporate Services at NDS Wellness, she helps design and deliver on-site health screening programs for employers and first responders, removing the barriers of participation so teams get real, physician-led care where they already are.