Who Signed Up, and
Who's Still Missing.
Nearly 40,000 Firefighters Have Joined the National Firefighter Registry for Cancer.
National Firefighter Registry for Cancer · First Three Years
The Breaking Science for the station >
About this study
- The study
- Siegel MR, Mayer AC, Fent KW, Wilkinson AF. Characteristics of Participants During the First Three Years of the National Firefighter Registry for Cancer, United States, January 2023–December 2025. American Journal of Industrial Medicine, 2026. doi:10.1002/ajim.70112 (NIOSH; open access, U.S. Government work)
- Why it exists
- In 2022 the International Agency for Research on Cancer classified occupational exposure as a firefighter as a Group 1 human carcinogen. Major gaps remain in what we know about cancer among U.S. firefighters, which is what the National Firefighter Registry (NFR) for Cancer, created by the Firefighter Cancer Registry Act of 2018, was built to fill.
- How to read this page
- Sections 1, 2, and 4, and the "What the study shows" half of Section 3, are reported from Siegel et al. 2026. Anything that is a Science to the Station recommendation rather than a study finding is labeled as such.
Key facts
39,058
firefighters enrolled in the NFR in its first three years
96%
provided enough information to be eligible for prospective cancer-registry linkage
Nearly 17%
of participants did not make it past the work history section
14% vs. ~65%
active volunteer or part-time: share of participants vs. NFPA estimate of the municipal workforce
1. Key findings
- 39,058 firefighters enrolled in the NFR in its first three years, from all 50 states plus Washington DC, Puerto Rico, and Guam. 4,019 reported a history of cancer.
- Who enrolled: 91% men / 9% women; 83% White; half were 25–44 years old. By work status: 75% active full-time, 14% active volunteer or part-time, 1% active other (seasonal, academy), 9% former service.
- Assignments ever held (participants could report more than one): structural firefighter 87%, structural firefighting leadership 49%, EMT/other 20%, wildland firefighter 17%, instructor 7%, wildland supervisor 6%, fire investigator 4%.
- Completion rates were high. Enrollment takes an estimated 40 minutes or more, yet 72% submitted the full enrollment questionnaire. A further 24% were "in progress." Together, 96% provided enough information to be eligible for prospective cancer-registry linkage; the remaining 4% stopped before providing the minimum information needed for linkage (full name, sex, and date of birth).
- 93% provided a partial Social Security number, an additional identifier that can strengthen record linkage. Participants can still be eligible for cancer-registry linkage without providing it. The authors note that low SSN reporting may be driven by a failure to complete the process rather than an unwillingness to provide the information.
- The largest drop-off occurred at work history, which the authors say appeared to be the largest barrier to completion. Nearly 17% of participants did not make it past the work history section and on to health history (90% started work history; 73% reached health history). Of those who started health history, only 1% dropped out before submitting.
- Volunteer underrepresentation is one of the registry's biggest representation gaps. Active volunteer or part-time firefighters were 14% of all participants (16% of active participants), while NFPA estimates they are about 65% of the national municipal firefighting workforce.
- Women are proportionally represented overall. Women were 9% of participants, matching NFPA's estimate of women in the national municipal firefighter workforce (9%). Women were 14% of active volunteer/part-time participants vs. 8% of active full-time.
- Black and Hispanic firefighters were enrolled in smaller proportions than their estimated share of the workforce: 2.8% Black and 4.1% Hispanic (9% Hispanic when counted without a separate "multiple races" category), against BLS 2024 estimates of about 10% and 15% of paid firefighters.
- Geographic participation was uneven. South Atlantic (24%) and Mountain (20%) divisions contributed the most; the Mountain division enrolled heavily despite being among the least populous, while West South Central (AR, LA, OK, TX) was underrepresented at 6%. The authors caution that comparisons to general population size should be interpreted carefully, since population size does not necessarily track firefighting workforce size.
- Recruitment route appeared to shape who enrolled (an exploratory analysis). Among active firefighters who completed enrollment, roster-based recruitment (15 Targeted Enrollment departments + 94 Gold Helmet departments) included more racially diverse firefighters. Most notably, it also showed a smaller proportion reporting a history of cancer (7% vs. 12%), consistent with reduced selection bias by cancer status and more generalizable data. Open Enrollment reached more volunteer/part-time firefighters (21% vs. 4%), wildland firefighters, structural leadership, and former firefighters.
How to read the 14% cancer figure
Overall, 14% of participants reported a history of cancer. Do not interpret this as a firefighter cancer prevalence estimate. Cancer history in the NFR was self-reported, NFR participation may be affected by cancer status (referred to as selection bias), and reporting was not limited to diagnoses that occurred after someone entered the fire service. Future cancer-registry linkages are intended to measure cancer incidence in this cohort.
Part 1
For firefighters
2. What this means for firefighters
- Carve out 40 minutes and expect the work history section to take some time. This is the section where nearly one in six people stopped. This section matters! Science to the Station recommendation: before you start, gather every department you've served, the years, and the assignments you held at each.
- You can save your progress and return. The study notes most participants did not finish in one sitting, and that email or text reminders are sent to people who haven't submitted, and will continue to be used.
- Stopping partway still counts. Participants who provided full name, sex, and date of birth have given the minimum information needed to check for future cancer diagnoses in state cancer registries. What's lost by stopping early is the work history and exposure detail, the part that will eventually let researchers ask whether your kind of firefighting carries different risk.
- The partial SSN is optional but useful. It's an additional identifier that can strengthen linkage to state cancer registries; it is not required to be eligible.
- Volunteers were substantially underrepresented: 14% of participants against roughly 65% of the workforce. The authors write that additional information on cancer rates and risk factors for volunteer firefighters may benefit this field of research. The study points to documented barriers for volunteers (time constraints, less predictable schedules, and less department-level health and safety infrastructure) as plausible contributors.
- Retirees matter. Among former firefighters who completed enrollment, 46% reported a history of cancer. Because many cancers have long latency periods, enrolling former firefighters helps the NFR capture earlier eras of firefighting exposure.
- Subspecialty assignments are represented. Wildland firefighters (17%), instructors (7%), and fire investigators (4%) are represented, and completion rates were no lower among those who ever worked in wildland firefighting even though many work-related questions were written around structural firefighting.
Part 2
For department leadership
3. Policy & department implications
What the study shows
- Roster-based recruitment appears especially useful for improving representativeness: it reached a more racially and ethnically diverse group and showed a lower proportion reporting cancer history, consistent with reduced selection bias by cancer status. Open Enrollment remains important for reaching former firefighters, volunteers, wildland firefighters, and others outside participating departments. The two approaches serve different purposes.
- Departments themselves drove most roster-based enrollment. Gold Helmet departments (which qualify at 50% or more of active firefighters enrolled, or more than 300 active firefighters) contributed most roster-based participants, and any department can pursue this by contacting NIOSH at NFRegistry@cdc.gov.
- The authors note the recruitment-route comparison is exploratory and vulnerable to misclassification, since route was inferred from department affiliation rather than tracked directly.
- The long-term stake: the NFR is designed to provide U.S.-specific evidence on cancer incidence and risk factors across the fire service. Over time, those findings can inform cancer-prevention practices and recommendations.
What departments can do
(Science to the Station recommendations, not findings from this study)
- Build enrollment into something that already exists (onboarding, annual physicals, or a block on a training day) and give people on-duty time and a computer.
- Hand out a pre-filled sheet of department names, service dates, and assignments. That removes the exact barrier this study identified.
- For volunteer departments, use drill nights, county or mutual-aid-wide campaigns, and state association pushes rather than expecting individual sign-ups.
- Deliberately reach the groups the study found underrepresented: volunteers, Black and Hispanic firefighters, underrepresented states and territories, and retirees who are no longer on any roster.
- Questions worth putting on a chief's agenda: Who owns NFR enrollment here? Are we a Gold Helmet candidate? Are we reaching our retirees? Do our volunteers know this exists?
4. Next steps & ongoing research
- The central open question is cancer incidence in this cohort. The NFR is designed for prospective follow-up by linking with population-based cancer registries and the National Death Index; those results are not part of this paper. The authors expect registry linkages to improve cancer ascertainment among the in-progress group over time.
- Also unanswered: how exposures, workplace practices, and health behaviors relate to cancer rates; how cancer burden varies across demographic, geographic, and subspecialty groups; and whether risk differs for groups that prior studies were too small to analyze, including women, non-White firefighters, volunteers, and wildland firefighters.
- The registry will keep enrolling. The web portal is built to accommodate voluntary follow-up questionnaires so participants can contribute longitudinally, alongside continued recruitment to capture new firefighters over time.
- Author-identified priorities: targeted recruitment of volunteer and non-White firefighters and underrepresented states and territories; continued vigorous roster-based recruitment to grow the sample and potentially offset selection bias; and focused communication and technical assistance, with push notifications, in-person guidance, and "train the trainer" material given as examples, to improve completion past the work history section.
- Possible future linkages. The authors note opportunities may exist to further develop participants' exposure and health profiles through linkage with other firefighting studies or systems, naming the Fire Fighter Cancer Cohort Study and the National Emergency Response Information System (NERIS). This is described as an opportunity, not a funded plan.
- Timeline: the NFR is built as a continuous surveillance system, and cancer latency means incidence findings will take years. The paper's data availability statement says the study data are in preparation for public data sharing under an Assurance of Confidentiality, with procedures currently under development. NIOSH confirms that the data to be shared will be deidentified, so identifying information will not be released. NIOSH directs inquiries to NFRegistry@cdc.gov.
- How to participate: all current and former U.S. firefighters aged 18 or older are eligible, regardless of health or cancer status, and enroll through the NIOSH NFR web portal. Department leadership can email NFRegistry@cdc.gov about Gold Helmet recognition or roster-based recruitment.
- How to stay informed: the NIOSH National Firefighter Registry for Cancer website, where firefighters can also subscribe to the registry's newsletter, and NFR findings as they publish.
Prepared by Science to the Station, a program of Science Alliance Inc. Study findings are reported from Siegel et al. 2026; recommendations labeled as ours are not study conclusions. Nothing here is medical advice; cancer screening decisions belong between a firefighter and their clinician.
Source notes. All statistics on this page come from Siegel et al. 2026, including the comparison figures the authors draw from NFPA's U.S. Fire Department Profile and 2024 Bureau of Labor Statistics data. Items sometimes questioned as outside the paper are located here: possible FFCCS/NERIS linkage and the recruitment/technical-assistance priorities are in the Discussion (p. 13); push notifications already in use are on p. 8; public data sharing "in preparation… procedures currently under development" is the Data Availability Statement (p. 14). The deidentification point is NIOSH's clarification in review, not language from the paper.