More than 15 million firefighters serve in 59 high- and middle-income countries worldwide (Brushlinsky, 2021), including over a million in the United States. Firefighters’ work and training environments routinely expose them to human carcinogens and other toxicants (Fent et al., 2017; Sparer et al., 2017). Occupational diseases associated with firefighting include sudden cardiovascular events, a leading cause of line-of-duty firefighter deaths (Kales et al., 2007), and some types of cancer (DeBono et al., 2023). Recently, the International Agency for Research on Cancer (IARC) classified firefighting as carcinogenic to humans (IARC, 2023). This determination was supported by findings demonstrating that the types of exposures incurred by firefighters can cause biological changes that lead to carcinogenesis; studies of cancer in humans showing increased risk for mesothelioma and bladder cancer; and emerging evidence for increased risk for melanoma of the skin, non-Hodgkin’s lymphoma (NHL), and cancers of the colon, prostate, and testes. The IARC Working Group indicated that the findings are relevant to all firefighters who train for and take part in fire control activities, including those who serve as volunteers (Demers et al., 2022).

About two-thirds (65%) of U.S. firefighters serve as volunteers (Fahy et al., 2022). Volunteer firefighters receive the same basic training and perform the same duties as career firefighters. While career firefighters respond to calls as assigned by their employers, volunteer firefighters typically choose which calls they respond to, within the framework of their department’s rules. Career firefighters usually work in extended shifts (e.g., 24 or 48 hours) during which they reside at their fire station. In contrast, most volunteer firefighters respond to calls from their workplaces, homes, or other locations.

In 2020, there were 29,425 active fire departments in the United States (Fahy et al., 2022). Most of these departments (64%) were comprised entirely of volunteer members, and 18% were classified as combination departments, which consisted primarily of volunteer members and at least some career firefighters (Fahy et al., 2022). Members of other departments were all or mostly career firefighters. While a majority of U.S. firefighters are volunteers, all-volunteer or mostly volunteer fire departments serve less than one-third of the U.S. population. This is because most volunteer fire departments serve less densely populated rural and suburban communities, while most career fire departments serve densely populated urban centers (Fahy et al., 2022).

While there is a robust literature evaluating cancer risk in firefighters (DeBono et al., 2023), few studies have included volunteer firefighters. This exclusion is likely due to the convenience of working with career firefighters during their shifts. Researchers working with career firefighters may also be able to access electronic employment records through the fire department or union. In some cases, researchers may also access historical occupational health records. The few studies of cancer incidence among volunteer firefighters suggest some increased risk for cancers of the prostate, rectum, kidneys, and testes (Glass et al., 2017, 2019; Pedersen et al., 2019; Petersen et al., 2018). Further, the contribution of firefighting to cancer rates may be challenging to interpret because U.S. cancer rates differ by rurality. Rural residents have higher rates of colon, rectum, and lung cancers, while urban residents have higher rates of prostate cancer and malignant melanoma (Zahnd et al., 2018).

Volunteer firefighters report responding to fewer calls than their career counterparts in the short term, but they spend more years in the fire service. Volunteer departments may have limited access to high quality and properly maintained protective equipment, infrastructure for health and safety, and routine health exams. Compared to career firefighters, volunteer firefighters appear to have different behavioral risk factors that contribute to cancer risk, including the two modifiable factors that contribute most to cancer incidence and mortality in the general population: tobacco use (Phan et al., 2022) and alcohol use (Haddock et al., 2012; Haddock et al., 2017). However, few studies have assessed these risk factors in a diverse population of volunteer firefighters.

The lack of information on how occupational and behavioral health risks vary between volunteer and career firefighters and between volunteer firefighters in different geographical areas, are important research gaps. These gaps impede the appropriate design and implementation of health promotion and disease prevention programs aimed at reducing cancer risk and improving the overall health of volunteer firefighters. The Fire Fighter Cancer Cohort Study (FFCCS; www.ffccs.org) is a national platform to study cancer and mechanisms of carcinogenesis among career firefighters that was established in the United States in 2016. In this article, we first describe the methodology and preliminary results from the Firefighter Cancer Assessment and Prevention Study (CAPS). CAPS is a research component designed by the FFCCS to involve volunteer firefighters in cancer etiology and prevention research and to address this research gap. Secondly, we present findings on the prevalence of cancer-related health behaviors from enrollment surveys of the volunteer firefighters enrolled in CAPS and the career firefighters enrolled in the FFCCS between November 2019 and January 2023.

Between January 1, 2019, and January 31, 2023, over 40 volunteer and combination fire departments from nine states (CT, IL, KS, MD, ME, MO, NJ, TN, WA) participated in the CAPS. Most participants enrolled through study events at their fire stations. Exceptions included one fire department each in southern Maine and middle Tennessee whose leadership held a study event for several rural departments located nearby. One fire department each in New Jersey and Illinois held the events at their local fire academies.

Of the 607 volunteer firefighters enrolled into the FFCCS through CAPS, 569 are included in this study. Thirty-eight of the original enrollees were excluded for not being a full fire department member (e.g., new recruit, n = 25) and not completing the survey (n = 13). CAPS researchers received records for 2,909 career firefighters enrolled into the FFCCS under a data use agreement. Working with FFCCS data managers, an analytical sample of 1,573 career firefighters was constructed after removing new recruits, duplicate records, records missing date of birth, participants who enrolled outside the study period, and those who withdrew without completing the survey (see Figure 2).

On average, volunteer and career firefighters spent a similar number of years in the fire service (14 and 12 years, respectively), but volunteers responded to a fifth of the calls per month that their career counterparts responded to (10 vs. 50). All volunteer firefighters enrolled through the CAPS served in communities with fewer than 100,000 people, whereas most career firefighters served in communities with over a million people. Forty percent of enrolled volunteers, but fewer than 1% of career firefighters, served communities with 10,000 or fewer people. Both the CAPS volunteer firefighters and the FFCCS career firefighters were predominantly non-Hispanic White (91% and 79%, respectively) and male (90% and 96%, respectively). Compared to the career firefighters, the volunteer firefighters had less education and lower incomes. A higher proportion of volunteers compared to career firefighters had a high school education or less (25% vs. 9%), and a lower proportion had an annual household income over $75,000. Over 80% of volunteer firefighters were employed, and over two thirds worked full-time (see Table 1).

Among volunteer firefighters, demographic and firefighting characteristics varied by state. Average years of service ranged from 9 (WA) to 20 (NJ), and the average number of monthly firefighting call responses ranged from 5 (TN) to 25 (WA). There was over a decade of difference in the average age of enrollees, from 34 years old (WA) to 47 years old (NJ) (see Table 2).

Compared to career firefighters, volunteer firefighters had a higher prevalence of current cigarette smoking (10% vs. 1%), but their use of smokeless tobacco was similar (10% vs. 11%). The prevalence of hazardous drinking was over 2.5 times higher in volunteers than their career counterparts (36% vs. 13%). Compared with career firefighters, volunteers had almost double the prevalence of obesity (43% vs. 23%) and a 3 times higher prevalence of being physically inactive (24% vs. 8%) (see Figure 3, p. 30).

State-level analyses are not displayed for Colorado (career), Connecticut (volunteer), and Maryland (volunteer), due to sample size. After adjustment for age, sex, and race-ethnicity, health behavior prevalence estimates varied substantially by state, with current cigarette use and heavy drinking varying more for volunteer than career firefighters. Among volunteer firefighters, the prevalence of current smoking ranged from none (WA) to 36% (TN). Among career firefighters, the prevalence was 1% or lower. In contrast, there was considerable variation by state in the proportion of both volunteer and career firefighters who currently used smokeless tobacco. The prevalence estimates varied more than five-fold: for volunteers 2% (NJ) to 13% (IL, MO & KS) and for careers 4% (FL) to 14% (CA). The prevalence of hazardous drinking appeared to vary more among volunteer firefighters (24% [TN] to 51% [NJ]) than among career firefighters (22% [MA] to 32% [FL]). The prevalence of obesity varied less by state for both groups of firefighters, but all state-level prevalence estimates for volunteer firefighters were higher than those of career firefighters (see Figure 4, p. 31).

Tobacco use is the preventable factor with the highest population attributable risk for cancer in the U.S. general population. Tobacco smoking causes cancer in most organs of the body such as the bladder and colon, sites known to be at a higher cancer risk among firefighters. Smokeless tobacco causes cancer of the oral cavity, esophagus, and pancreas. Tobacco use also incurs other health risks, including exposure to nicotine, the addictive ingredient in tobacco. Nicotine can increase blood pressure and cholesterol levels, thereby increasing the risk of cardiovascular disease.

In 2020, the Centers for Disease Control and Prevention (CDC) estimated that 13% (95% CI: 11.9, 13.0) of U.S. adults currently smoked cigarettes, and 2.3% (95% CI: 2.1, 2.6) currently used smokeless tobacco. Both smoking and smokeless tobacco use have declined among career firefighters since the early 1990s. While smoking prevalence among firefighters has consistently been lower than among other occupational groups (Phan et al., 2022), the proportion of firefighters who use smokeless tobacco has been much higher than that of the general population. In our study overall, 8.8% of volunteer and 10.6% of career firefighters currently used smokeless tobacco. This is consistent with a study by Jitnarin et al. (2013) that surveyed 353 male career firefighters in Missouri between May 2008 and May 2010. That study found that 13% of respondents were current smokeless tobacco users.

According to 2020 data (Cornelius, 2022), current smoking and smokeless tobacco use in the U.S. general population is higher among men than women (smoking: 14.1% vs. 11.0%; smokeless tobacco use: 4.5% vs. 0.3%). Tobacco use is also higher among people living in rural areas than among people living in urban areas (smoking: 19.0% vs. 11.4%; smokeless tobacco use 5.9% vs. 1.7%). In our study, over 90% of volunteer firefighters were men, and almost two thirds served communities with 25,000 or fewer people. The distribution of smokeless tobacco use in the general population may, in part, account for the proportion of smokeless tobacco users observed among the more rural volunteer firefighters. In occupations where smoking is prohibited, other forms of tobacco, including smokeless tobacco, may be used in higher proportion as a way to facilitate nicotine addiction through non-combustible alternatives (Graber et al., 2016). No matter the root causes of smokeless tobacco use among firefighters, prioritizing efforts to reduce its use in the fire service may provide substantial reduction in cancer risk.

In many U.S. states, tobacco smoking is restricted or prohibited by the terms of employment for firefighters. This is consistent with our finding that few career firefighters reported being current cigarette smokers. However, the underreporting of smoking by those career firefighters for whom not smoking is a condition of employment may also contribute to the observed difference in smoking prevalence. In contrast, smoking prevalence among volunteer firefighters in our study was more like that of the general population. While smoking is also prohibited in many volunteer fire departments, the impact on smoking behaviors is likely reduced for volunteers compared to career firefighters, as volunteers spend less time in their fire stations.

Alcohol is a human carcinogen (Baan et al., 2007) and is associated with cancer of the head and neck, breast, pancreas, liver, colon, and rectum. Consistent with other studies, a higher proportion of both volunteer and career firefighters in our study screened positive for hazardous drinking and alcohol use disorder. Hazardous drinking was highly prevalent among both career and volunteer firefighters. To date, there are relatively few studies reporting alcohol use among firefighters. Haddock et al. (2015) studied 954 male career firefighters enrolled from 20 fire departments in 14 U.S. states. Over 85% of the firefighters consumed alcohol, and 45% reported heavy drinking. Heavy drinking was defined for this study as an average of three or more drinks a day. Half of the firefighters in the study (50.2%) reported at least one heavy drinking episode in the past 30 days, which was defined as 5 drinks or more on an occasion. By comparison, about 13% of U.S. men, age 18 and older, screen as having alcohol use disorder (National Institutes of Health, 2023).

Physical fitness is more than a requisite for firefighters to perform their duties. Physical fitness is associated with reduced risk of cancers of the bladder, prostate, and rectum, as well as melanoma and lymphoma (Robsahm et al., 2017). Obesity is a key indicator of poor physical fitness and associated with many types of cancer, including cancers of the digestive and hematopoietic systems (National Institutes of Health, National Cancer Institute, 2023). Our findings are consistent with other studies showing that, after adjusting for age, the prevalence of obesity in male career firefighters was similar to that of the general population (33% vs. 34%). Volunteer firefighters had a larger prevalence of obesity (39%) than career firefighters or the general population (Poston et al., 2011).

This study has some limitations that should be considered when interpreting the findings. The CAPS and the FFCCS used convenience sampling to identify fire departments interested in this collaborative research project. This sampling approach may have introduced selection bias, as it is likely that fire departments with leadership and members who are aware of health issues related to the fire service were more likely to participate than departments with less awareness. As a result, fire departments with a strong culture of health promotion may have enrolled in the study more often than those without this culture. If this is the case, our results may underestimate the prevalence of adverse health behaviors. Another limitation was for the enrolled FFCCS career firefighters. Some variables had a considerable amount of missing survey data. Fifty-nine percent (59%) of the responses from the FFCCS firefighters were missing information for at least one study variable, compared to 12% of the responses from the CAPS firefighters. We used multiple imputation, a robust statistical technique, to estimate these values. There were fewer missing data for the variables included to estimate the adjusted prevalence estimates. Seventeen percent (17%) of the FFCCS participants and 2% of the CAPS participants included in these analyses had one or more missing values.

An additional consideration is that, unlike career fire service members, volunteer fire department members do not retire. These firefighters tend to remain a volunteer member with reduced response activities, such as assisting with crowd control at fire scenes. We restricted our state-level comparisons to firefighters aged 60 and under to address this discrepancy. Additionally, the definitions used to classify heavy drinking differed between the FFCCS and the CAPS surveys. This may account for some of the observed differences between career and volunteer firefighters. Finally, the reasons that career firefighters had a higher average household income and more years of formal education are unclear, but they may reflect geographic differences in the CAPS and the FFCCS enrollments. Despite these limitations, our study expands health research on volunteer firefighters by integrating and consolidating multiple influencers of firefighter health and by including firefighters from across the United States.

Our study quantified important differences in the distribution of cancer-related health behaviors among career and volunteer firefighters. Equally important, we saw considerable variation in these health behaviors among both career and volunteer firefighters at the state level. These differences have implications for health promotion and cancer prevention activities. They emphasize the need to first understand health behaviors within a given department when planning tailored health promotion interventions. In addition to improving firefighter health and safety, such interventions have the potential to change department culture, attract new members, and improve membership retention. These findings also highlight the importance of engaging with firefighters as research partners and including volunteer firefighters in studies of firefighter health.