Firefighters are occupationally exposed to many chemicals, including polycyclic aromatic hydrocarbons (PAHs), which are formed by the incomplete combustion of organic matter during fire response and training activities. However, due to the harsh environments in which firefighters work, as well as consideration for time and physical safety while wearing bulky equipment, traditional active sampling methods may not be feasible to measure PAH exposures. Silicone passive samplers offer an alternative approach to assess exposure during fire responses and live fire training due to their heat resistance and ease of deployment in remote or time-limited environments. In this study, the primary objective was to investigate and determine the statistical strength of the relationship between active air sampling methods and passive silicone samplers for PAHs. In this study, silicone wristbands were paired with active sampling devices in a series of burn experiments to compare PAH measurements. Silicone-based measurements correlated strongly with active air samples for the dominant PAHs found, naphthalene and phenanthrene; however, detection was limited in the wristbands when air concentrations were low in active samples. In situations where PAH levels are expected to be high and the potential for contaminant loss via off-gassing is low, silicone samplers may be a useful tool for industrial hygienists to measure PAHs in fire and other emergency responses in extreme environments.

Wildland-urban interface (WUI) firefighting involves exposure to burning vegetation, structures, and other human-made hazards, often without respiratory protection. Response activities can last for long periods of time, spanning multiple days or weeks. Epigenetic modifications, including microRNA (miRNA) expression and DNA methylation, are responsive to toxicant exposures and are part of the development of cancers and other diseases. Epigenetic modifications have not been studied in relation to WUI fires. Firefighters (n = 99) from southern California, including 79 firefighters who responded to at least one WUI fire, provided blood samples at baseline and approximately 10 months later. We quantified the relative abundance of 800 miRNAs in blood samples using the nCounter Human v3 miRNA expression panel and blood leukocyte DNA methylation throughout the genome via the Infinium EPIC array. We used linear mixed models to compare the expression of each miRNA across time and DNA methylation at each locus, adjusting for potential confounders. In the miRNA analysis among all firefighters, 65 miRNAs were significantly different at follow-up compared to baseline at a false discovery rate of 5%. Results were similar when restricted to firefighters with a recorded WUI fire exposure during the interim period, although only 50 were significant. Expression of miRNA hsa-miR-518c-3p, a tumor suppressor, was significantly associated with WUI fire response (fold change 0.77, 95% CI = [0.69, 0.87]). In the DNA methylation analysis, no statistically significant changes over time were identified. In summary, WUI fire exposures over a wildfire season altered miRNA expression but did not substantially impact DNA methylation.

OBJECTIVE: To describe volunteer firefighters' perspectives on how firefighter- and fire department-level factors influence their physical activity and fitness. METHODS: Firefighters (n = 28) were interviewed, stratified by their years of firefighting, using an interview guide. Thematic analysis and systematic coding were employed to analyze the interview transcripts. RESULTS: Five themes were identified: (1) health and firefighting performance; (2) firefighter time and availability; (3) responsibility of the fire department to support volunteer members' physical fitness; (4) fire training drills as a form of functional physical activity, and (5) fitness initiatives at the department. Interviewing by years of experience showed varied perspectives which converged towards similar conclusions. CONCLUSIONS: Incorporating fitness discussions into department meetings and trainings, and identifying fitness advocates within the department, may contribute to overcoming barriers to physical fitness among volunteer firefighters.

Prostate cancer is the leading incident cancer among men in the United States. Firefighters are diagnosed with this disease at a rate 1.21 times higher than the average population. This increased risk may result from occupational exposures to many toxicants, including per- and polyfluoroalkyl substances (PFAS). This study assessed the association between firefighting as an occupation in general or PFAS serum levels, with DNA methylation. Only genomic regions previously linked to prostate cancer risk were selected for analysis: GSTP1, Alu repetitive elements, and the 8q24 chromosomal region. There were 444 male firefighters included in this study, with some analyses being conducted on fewer participants due to missingness. Statistical models were used to test associations between exposures and DNA methylation at CpG sites in the selected genomic regions. Exposure variables included proxies of cumulative firefighting exposures (incumbent versus academy status and years of firefighting experience) and biomarkers of PFAS exposures (serum concentrations of 9 PFAS). Proxies of cumulative exposures were associated with DNA methylation at 15 CpG sites and one region located within FAM83A (q-value <0.1). SbPFOA was associated with 19 CpG sites (q < 0.1), but due to low detection rates, this PFAS was modeled as detected versus not detected in serum. Overall, there is evidence that firefighting experience is associated with differential DNA methylation in prostate cancer risk loci, but this study did not find evidence that these differences are due to PFAS exposures specifically.

BACKGROUND: Although firefighters have increased risk for colon and prostate cancer, limited information exists on screening practices for these cancers in volunteer firefighters who compose two-thirds of the US fire service. We estimated the prevalence of colon and prostate cancer screening among volunteer firefighters using eligibility criteria from 4 evidence-based screening recommendations and evaluated factors influencing screening. METHODS: We evaluated colon (n = 569) and prostate (n = 498) cancer screening prevalence in a sample of US volunteer firefighters using eligibility criteria from the US Preventive Services Taskforce (USPSTF), National Fire Protection Association, American Cancer Society, and National Comprehensive Cancer Network. We assessed associations with fire service experience, demographics, and cancer risk perception based on USPSTF guidelines. RESULTS: For those eligible based on USPSTF guidelines, colon and prostate cancer screening prevalence was 51.7% (95% CI: 45.7, 57.8) and 48.8% (95% CI: 40.0, 57.6), respectively. Higher odds of colon and prostate cancer screening were observed with older age and with some college education compared to those with less education. Fire service experience and cancer risk perception were not associated with screening practices. CONCLUSION: This is the first large study to assess colon and prostate cancer screening among US volunteer firefighters based on different screening guidelines. Our findings suggest gaps in cancer prevention efforts in the US volunteer fire service. Promoting cancer screening education and opportunities for volunteer firefighters by their fire departments, healthcare professionals, and public health practitioners, may help to address the gaps.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) comprise a large group of chemicals that have been integrated into a wide variety of industrial processes and consumer products since the 1950s. Due to their profuse usage and high persistence in human serum, understanding workplace exposures to PFAS is critical. OBJECTIVE: We aimed to characterize the PFAS exposure profiles of relevant occupational populations, elucidate trends in the PFAS exposure characterization process, and identify major research gaps that remain within the occupational PFAS exposure literature. METHODS: A systematic search of four literature databases for peer-reviewed articles published between 1980 and 2021 on PFAS exposure in occupational settings was conducted. RESULTS: Of the 2574 articles identified, 92 met the inclusion criteria. Fluorochemical workers were the target population in most early exposure assessment research; however, studies conducted within the last 10 years have evaluated a wider range of occupational populations and settings. The highest exposures were reported in fluorochemical workers, but, in comparison to reference populations, one or more PFAS were elevated in most workers and in most workplaces that were assessed. PFAS was most frequently assessed in worker serum using a discrete analytical panel of PFAS, with earlier studies restricted to a few long-alkyl chain PFAS while more recent studies have included more expansive panels due to more robust methods. SIGNIFICANCE: Characterization of occupational exposure to PFAS is limited but expanding. Current analytical methods are not robust enough to fully capture the potential range of PFAS present across different workers and workplaces. While exposures to PFAS for certain occupational groups have been studied in detail, exposure information for other occupational groups with high potential for exposure are limited. This review highlights substantial findings and major research gaps within the occupational literature.

There is a substantial burden of occupational health effects from heat exposure. We sought to assess the accuracy of estimated core body temperature (CBT(est)) derived from an algorithm that uses sequential heart rate and initializing CBT,(1) compared with gastrointestinal temperature measured using more invasive ingestible sensors (CBT(gi)), among outdoor agricultural workers. We analyzed CBT(est) and CBT(gi) data from Washington State, USA, pear and apple harvesters collected across one work shift in 2015 (13,413 observations, 35 participants) using Bland Altman methods. The mean (standard deviation, range) CBT(gi) was 37.7 (0.4, 36.5-39.4)C. Overall CBT bias (limits of agreement) was -0.14 (0.76)C. Biases ranged from -0.006 to -0.75C. The algorithm, which does not require the use of ingestible sensors, may be a practical tool in research among groups of workers for evaluating the effectiveness of interventions to prevent adverse occupational heat health effects.

BACKGROUND: Firefighters have occupational and environmental exposures to per- and polyfluoroalkyl substances (PFAS). The goal of this study was to compare serum PFAS concentrations across multiple United States fire departments to National Health and Nutrition Examination Survey (NHANES) participants. METHODS: Nine serum PFAS were compared in 290 firefighters from four municipal fire departments (coded A-D) and three NHANES participants matched to each firefighter on sex, ethnicity, age, and PFAS collection year. Only Departments A and C had sufficient women study participants (25 and six, respectively) to compare with NHANES. RESULTS: In male firefighters compared with NHANES, geometric mean perfluorohexane sulfonate (PFHxS) was elevated in Departments A-C, sum of branched perfluoromethylheptane sulfonate isomers (Sm-PFOS) was elevated in all four departments, linear perfluorooctane sulfonate (n-PFOS) was elevated in Departments B and C, linear perfluorooctanoate (n-PFOA) was elevated in Departments B-D, and perfluorononanoate (PFNA) was elevated in Departments B-D, but lower in A. In male firefighters compared with NHANES, perfluoroundecanoate (PFUnDA) was more frequently detected in Departments B and D, and 2-(N-methyl-perfluorooctane sulfonamido) acetate (MeFOSAA) was less frequently detected in Departments B-D. In female firefighters compared with NHANES, PFHxS and Sm-PFOS concentrations were elevated in Departments A and C. Other PFAS concentrations were elevated and/or reduced in only one department or not significantly different from NHANES in any department. CONCLUSIONS: Serum PFHxS, Sm-PFOS, n-PFOS, n-PFOA, and PFNA concentrations were increased in at least two of four fire departments in comparison to NHANES.

Over the past few decades, there has been a growing concern over the health effects associated with per- and polyfluoroalkyl substances (PFAS) exposure especially among worker populations. High levels of PFAS exposure have been linked to various health outcomes including cancer and increased cholesterol levels.1 Existing research on occupational PFAS exposure is limited to only a few industries. Given this, the focus of the American Journal of Industrial Medicine's special issue on occupational PFAS exposures is to review current knowledge of occupational exposures to PFAS; identify newer, emerging, or unstudied sources of exposure; assess gaps in present understanding of their occupational use and hazards; and outline the needs for future research and worker protection. This special issue will help advance the scientific community's understanding of PFAS and aid current and future research projects. However, there are additional critical drivers to the success of reducing occupational exposures to PFAS which need to be addressed. These critical drivers are effective coordination, collaboration, communication, and partnerships.

Background: Per- and polyfluoroalkyl substances (PFASs) are persistent chemicals that firefighters encounter. Epigenetic modifications, including DNA methylation, could serve as PFASs toxicity biomarkers. Methods: With a sample size of 197 firefighters, we quantified the serum concentrations of nine PFASs, blood leukocyte DNA methylation and epigenetic age indicators via the EPIC array. We examined the associations between PFASs with epigenetic age, site- and region-specific DNA methylation, adjusting for confounders. Results: Perfluorohexane sulfonate, perfluorooctanoate (PFOA) and the sum of branched isomers of perfluorooctane sulfonate (Sm-PFOS) were associated with accelerated epigenetic age. Branched PFOA, linear PFOS, perfluorononanoate, perfluorodecanoate and perfluoroundecanoate were associated with differentially methylated loci and regions. Conclusion: PFASs concentrations are associated with accelerated epigenetic age and locus-specific DNA methylation. The implications for PFASs toxicity merit further investigation.

OBJECTIVES: We use a qualitative method to gain further insight into women firefighters' experiences, perceptions of cancer, health and safety risks in the fire service. METHODS: We conducted six focus groups with U.S. women firefighters. Participants engaged in a 60-75-minute, semi-structured discussion and completed a sociodemographic questionnaire. A qualitative descriptive approach was used to inductively create themes. Data collection concluded when saturation was met. RESULTS: Forty-nine women firefighters participated. Qualitative results indicated the main health concerns include: Occupational cancer risks including, risks related to hazardous exposures, sleep disruption and stress; and Women's health concerns including, cancer, pregnancy and breastfeeding and lack of resources. CONCLUSIONS: Women firefighters are concerned about their risk for cancer due to their occupation and identify a lack of resources specific to health and safety needs of women firefighters.

Firefighters are exposed to a variety of environmental hazards and are at increased risk for multiple cancers. There is evidence that risks differ by ethnicity, yet the biological or environmental differences underlying these differences are not known. DNA methylation is one type of epigenetic regulation that is altered in cancers. In this pilot study, we profiled DNA methylation with the Infinium MethylationEPIC in blood leukocytes from 31 Hispanic white and 163 non-Hispanic white firefighters. We compared DNA methylation (1) at 12 xenobiotic metabolizing genes and (2) at all loci on the array (>740 000), adjusting for confounders. Five of the xenobiotic metabolizing genes were differentially methylated at a raw P-value <.05 when comparing the 2 ethnic groups, yet were not statistically significant at a 5% false discovery rate (q-value <.05). In the epigenome-wide analysis, 76 loci exhibited DNA methylation differences at q <.05. Among these, 3 CpG sites in the promoter region of the biotransformation gene SULT1C2 had lower methylation in Hispanic compared to non-Hispanic firefighters. Other differentially methylated loci included genes that have been implicated in carcinogenesis in published studies (FOXK2, GYLTL1B, ZBTB16, ARHGEF10, and more). In this pilot study, we report differential DNA methylation between Hispanic and non-Hispanic firefighters in xenobiotic metabolism genes and other genes with functions related to cancer. Epigenetic susceptibility by ethnicity merits further study as this may alter risk for cancers linked to toxic exposures.

PURPOSE OF REVIEW: The burden of heat-related adverse occupational health effects, as well as traumatic injuries, is already substantial. Projected increases in mean temperatures and extreme events may increase the risk of adverse heat health effects and enhance disparities among exposed workers. This article reviews the emerging literature on the relationship between heat exposure and occupational traumatic injuries and discusses implications of this work. RECENT FINDINGS: A recent meta-analysis of three case-crossover and five time series studies in industrialized settings reported an association of increasing occupational injuries with increasing heat exposure, with increased effect estimates for male gender and age less than 25 years, although heterogeneity in exposure metrics and sources of bias were demonstrated to varying degrees across studies. A subsequent case-crossover study in outdoor construction workers reported a 0.5% increase in the odds of traumatic injuries per 1 degrees C increase in maximum daily humidex (odds ratio 1.005 [95% CI 1.003-1.007]). While some studies have demonstrated reversed U-shaped associations between heat exposure and occupational injuries, different risk profiles have been reported in different industries and settings. Studies conducted primarily in industrialized settings suggest an increased risk of traumatic injury with increasing heat exposure, though the exact mechanisms of heat exposure's effects on traumatic injuries are still under investigation. The effectiveness of heat-related injury prevention approaches has not yet been established. To enhance the effectiveness of prevention efforts, prioritization of approaches should take into account not only the hierarchy of controls, social-ecological models, community and stakeholder participation, and tailoring of approaches to specific local work settings, but also methods that reduce local and global disparities and better address the source of heat exposure, including conservation-informed land-use planning, built environment, and prevention through design approaches. Participation of occupational health experts in transdisciplinary development and integration of these approaches is needed.

The U.S. Navy developed Aqueous Film Forming Foam (AFFF) in the 1960s containing per- and polyfluoroalkyl subsances (PFAS) and synthetic foaming surfactants that allowed for improved firefighter safety, particularly for firefighters involved in liquid fuel and crash fire rescue operations and those using nozzles during structural firefighting.1 PFAS are also commonly used to water and stain-proof specific textiles such as the materials used to construct firefighter turnout gear.2,3 AFFFs have evolved to include a number of different formulations (including AFFFs that meet Military Specifications (MILSPEC), alcohol-resistant aqueous film-forming foam (AR-AFFF), etc.) that often, but not always, rely on PFAS compounds for proper foam performance. AFFFs used to fight Class B petroleum fires have historically contained longer chain PFAS such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)4–6 which are associated with adverse health outcomes.7,8 PFOS use in new AFFFs and other products were banned in the European Union in 2011 and Canada in 2013, and major U.S. manufacturers of AFFF indicated they would no longer produce PFOA-based fluorosurfactant foams after 2015.9,10 However, AFFF typically have a long shelf life of up to 25 years.11 Additionally, current fluorinated AFFF contain shorter chain PFAS chemicals with less information on potential toxicity. Little is known about AFFF use and knowledge of legacy and current PFOA and PFOS chemicals among firefighters.

INTRODUCTION: Several high-profile cases in the U.S. have drawn public attention to the use of lethal force by law enforcement (LE), yet research on such fatalities is limited. Using data from a public health surveillance system, this study examined the characteristics and circumstances of these violent deaths to inform prevention. METHODS: All fatalities (N=812) resulting from use of lethal force by on-duty LE from 2009 to 2012 in 17 U.S. states were examined using National Violent Death Reporting System data. Case narratives were coded for additional incident circumstances. RESULTS: Victims were majority white (52%) but disproportionately black (32%) with a fatality rate 2.8 times higher among blacks than whites. Most victims were reported to be armed (83%); however, black victims were more likely to be unarmed (14.8%) than white (9.4%) or Hispanic (5.8%) victims. Fatality rates among military veterans/active duty service members were 1.4 times greater than among their civilian counterparts. Four case subtypes were examined based on themes that emerged in incident narratives: about 22% of cases were mental health related; 18% were suspected "suicide by cop" incidents, with white victims more likely than black or Hispanic victims to die in these circumstances; 14% involved intimate partner violence; and about 6% were unintentional deaths due to LE action. Another 53% of cases were unclassified and did not fall into a coded subtype. Regression analyses identified victim and incident characteristics associated with each case subtype and unclassified cases. CONCLUSIONS: Knowledge about circumstances of deaths due to the use of lethal force can inform the development of prevention strategies, improve risk assessment, and modify LE response to increase the safety of communities and officers and prevent fatalities associated with LE intervention.