Exposure-response relationships for select cancer and non-cancer health outcomes in a cohort of U.S. firefighters from San Francisco, Chicago and Philadelphia (1950-2009)

Rapid Screening of Urinary 1-Hydroxypyrene Glucuronide by Multisegment Injection-Capillary Electrophoresis-Tandem Mass Spectrometry: A High-Throughput Method for Biomonitoring of Recent Smoke Exposures

Urinary 1-hydroxypyrene (HP) is a widely used biomarker of polycyclic aromatic hydrocarbon exposure relevant for biomonitoring the deleterious health impacts from tobacco smoke and ambient air pollution, as well as the hazards of certain occupations. Conventional methods for urinary HP analysis based on liquid chromatography with native fluorescence detection or tandem mass spectrometry (MS/MS) and gas chromatography-mass spectrometry (GC-MS) are limited by low sample throughput and complicated sample workup protocols that are prone to bias. Herein, we introduce a high throughput method to directly analyze the intact glucuronide conjugate of HP (HP-G) in human urine after a simple acidified ether extraction procedure when using multisegment injection-capillary electrophoresis-tandem mass spectrometry (MSI-CE-MS/MS). Multiplexed analyses of 13 independent urine extracts are achieved in a single run (<3 min/sample) with stringent quality control while avoiding enzyme deconjugation and precolumn chemical derivatization. Method validation demonstrates good technical precision (CV = 7.7%, n = 45) and accuracy with a mean recovery of (93 ± 3%) for urinary HP-G at three concentration levels with adequate detection limits (7 ng/L, S/N = 3). An interlaboratory method comparison of urine samples collected from firefighters deployed in the 2016 Fort McMurray wildfire also confirms good mutual agreement with an acceptable negative bias (mean bias = 15%, n = 55) when measuring urinary HP-G by MSI-CE-MS/MS as compared to total hydrolyzed urinary HP by GC-MS due to the low residual levels of free HP and its sulfate conjugate. This multiplexed separation platform is optimal for large-scale biomonitoring studies of air pollution relevant to global health as well as occupational smoke exposures in firefighters susceptible to dermal PAH absorption when using personal protective equipment.

Discovery of firefighter chemical exposures using military-style silicone dog tags

Occupational chemical hazards in the fire service are hypothesized to play a role in increased cancer risk, and reliable sampling technologies are necessary for conducting firefighter chemical exposure assessments. This study presents the military-style dog tag as a new configuration of silicone passive sampling device to sample individual firefighters' exposures at one high and one low fire call volume department in the Kansas City, Missouri metropolitan area. The recruited firefighters (n = 56) wore separate dog tags to assess on- and off-duty exposures (n_dogtags = 110), for a total of 30 24 h shifts. Using a 63 PAH method (GC-MS/MS), the tags detected 45 unique PAHs, of which 18 have not been previously reported as firefighting exposures. PAH concentrations were higher for on- compared to off-duty tags (0.25 < Cohen's d ≤ 0.80) and for the high compared to the low fire call volume department (0.25 ≤ d < 0.70). Using a 1530 analyte screening method (GC-MS), di-n-butyl phthalate, diisobutyl phthalate, guaiacol, and DEET were commonly detected analytes. The number of fire attacks a firefighter participated in was more strongly correlated with PAH concentrations than firefighter rank or years in the fire service. This suggested that quantitative data should be employed for firefighter exposure assessments, rather than surrogate measures. Because several detected analytes are listed as possible carcinogens, future firefighter exposure studies should consider evaluating complex mixtures to assess individual health risks.

Cancer Perceptions Among Smokeless Tobacco Users: A Qualitative Study of US Firefighters

Background

Prevalence rates of smokeless tobacco (SLT) use among firefighters are remarkably high and substantially higher than similar occupational groups and the general U.S. population. The purpose of this study was to explore the perspectives of fire service personnel regarding cancer and its associations with tobacco and SLT use.

Methods

This descriptive study used a qualitative approach. Key informant interviews were conducted in 39 career firefighters and fire service administration from across the U.S. Discussion were recorded, transcribed verbatim and transferred to NVivo software for narrative analysis. Topics explored included cancer perceptions, attitudes and beliefs, and cultural factors related to SLT use behaviors. Results: Major themes that emerged among fire service personnel included concerns about cancer and its risk factors including firefighting tasks, such as fire overhaul operations, and from their lifestyle behaviors, such as alcohol and tobacco use. Firefighters also suggested a number of reasons for their increased SLT use, such as fire department tobacco-free policy and fire service culture.

Conclusion

The current study provides a rich foundation for future research, prevention, and intervention efforts for the fire service and research communities regarding tobacco and SLT use and cancer risk. Additional research on firefighters' cancer beliefs deserves future research in order to improve messaging about the risks of cancer due to firefighting.

Integrating Exposure Knowledge and Serum Suspect Screening as a New Approach to Biomonitoring: An Application in Firefighters and Office Workers

Firefighters (FF) are exposed to recognized and probable carcinogens, yet there are few studies of chemical exposures and associated health concerns in women FFs, such as breast cancer. Biomonitoring often requires a priori selection of compounds to be measured, and so, it may not detect relevant, lesser known, exposures. The Women FFs Biomonitoring Collaborative (WFBC) created a biological sample archive and conducted a general suspect screen (GSS) to address this data gap. Using liquid chromatography-quadrupole time-of-flight tandem mass spectrometry, we sought to identify candidate chemicals of interest in serum samples from 83 women FFs and 79 women office workers (OW) in San Francisco. We identified chemical peaks by matching accurate mass from serum samples against a custom chemical database of 722 slightly polar phenolic and acidic compounds, including many of relevance to firefighting or breast cancer etiology. We then selected tentatively identified chemicals for confirmation based on the following criteria: (1) detection frequency or peak area differences between OW and FF; (2) evidence of mammary carcinogenicity, estrogenicity, or genotoxicity; and (3) not currently measured in large biomonitoring studies. We detected 620 chemicals that matched 300 molecular formulas in the WFBC database, including phthalate metabolites, phosphate flame-retardant metabolites, phenols, pesticides, nitro and nitroso compounds, and per- and polyfluoroalkyl substances. Of the 20 suspect chemicals selected for validation, 8 were confirmed-including two alkylphenols, ethyl paraben, BPF, PFOSAA, benzophenone-3, benzyl p-hydroxybenzoate, and triphenyl phosphate-by running a matrix spike of the reference standards and using m/z, retention time, and the confirmation of at least two fragment ions as criteria for matching. GSS provides a powerful high-throughput approach to identify and prioritize novel chemicals for biomonitoring and health studies.

Cancer risk among career male and female Florida firefighters: Evidence from the Florida Firefighter Cancer Registry (1981-2014)

BACKGROUND

Firefighters are at increased risk for select cancers. However, many studies are limited by relatively small samples, with virtually no data on the cancer experience of female firefighters. This study examines cancer risk in over 100,000 career Florida firefighters including 5000 + females assessed over a 34-year period.

METHODS

Florida firefighter employment records (n = 109 009) were linked with Florida Cancer Data System registry data (1981-2014; ~3.3 million records), identifying 3760 male and 168 female-linked primary cancers. Gender-specific age and calendar year-adjusted odds ratios (aOR) and 95% confidence intervals for firefighters vs non-firefighters were calculated.

RESULTS

Male firefighters were at increased risk of melanoma (aOR = 1.56; 1.39-1.76), prostate (1.36; 1.27-1.46), testicular (1.66; 1.34-2.06), thyroid (2.17; 1.78-2.66) and late-stage colon cancer (1.19;1.00-1.41). Female firefighters showed significantly elevated risk of brain (2.54; 1.19-5.42) and thyroid (2.42; 1.56-3.74) cancers and an elevated risk of melanoma that approached statistical significance (1.68; 0.97-2.90). Among male firefighters there was additional evidence of increased cancer risk younger than the age of 50 vs 50 years and older for thyroid (2.55; 1.96-3.31 vs 1.69; 1.22-2.34), prostate (1.88; 1.49-2.36 vs 1.36; 1.26-1.47), testicular (1.60; 1.28-2.01 vs 1.47; 0.73-2.94), and melanoma (1.87; 1.55-2.26 vs 1.42; 1.22-1.66) cancers.

CONCLUSION

Male career firefighters in Florida are at increased risk for five cancers with typically stronger associations in those diagnosed younger than the age of 50, while there was evidence for increased thyroid and brain cancer, and possibly melanoma risk in female firefighters. Larger cohorts with adequate female representation, along with the collection of well-characterized exposure histories, are needed to more precisely examine cancer risk in this occupational group.

Exposure to Perfluoroalkyl Substances in a Cohort of Women Firefighters and Office Workers in San Francisco

Studies of firefighters have shown increased exposures to carcinogenic compounds and elevated rates of certain cancers compared to the general population, yet this research has focused almost exclusively on men. To address this gap, the Women Firefighters Biomonitoring Collaborative created a biological sample archive and analyzed levels of perfluoroalkyl substances (PFAS) among women firefighters (N = 86) and office workers (N = 84) in San Francisco. Serum samples were collected and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to measure and compare PFAS levels between firefighters and office workers. 7 of 12 PFAS congeners were detected in the least 70% of the study population, and 4 congeners were detected in 100% of participants. In regression models comparing PFAS levels by occupation and adjusting for potential confounders, firefighters had higher geometric mean concentrations of PFAS compared to office workers PFHxS (2.22 (95% CI = 1.55, 3.18)), PFUnDA (1.83 (95% CI = 0.97, 3.45)), and PFNA (1.26 (95% CI = 1.01, 1.58)). Among firefighters, occupational position predicted exposure-firefighters and officers had higher PFNA, PFOA, PFDA, and PFUnDA levels compared to drivers. Women firefighters are exposed to higher levels of some PFAS compared to office workers, suggesting that some of these exposures may be occupationally related.

Firefighters' absorption of PAHs and VOCs during controlled residential fires by job assignment and fire attack tactic

To better understand the absorption of combustion byproducts during firefighting, we performed biological monitoring (breath and urine) on firefighters who responded to controlled residential fires and examined the results by job assignment and fire attack tactic. Urine was analyzed for metabolites of polycyclic aromatic hydrocarbons (PAHs) and breath was analyzed for volatile organic compounds (VOCs) including benzene. Median concentrations of PAH metabolites in urine increased from pre-firefighting to 3-h post firefighting for all job assignments. This change was greatest for firefighters assigned to attack and search with 2.3, 5.6, 3.9, and 1.4-fold median increases in pyrene, phenanthrene, naphthalene, and fluorene metabolites. Median exhaled breath concentrations of benzene increased 2-fold for attack and search firefighters (p < 0.01) and 1.4-fold for outside vent firefighters (p = 0.02). Compared to interior attack, transitional attack resulted in 50% less uptake of pyrene (p = 0.09), 36% less uptake phenanthrene (p = 0.052), and 20% less uptake of fluorene (p < 0.01). Dermal absorption likely contributed to firefighters' exposures in this study. Firefighters' exposures will vary by job assignment and can be reduced by employing a transitional fire attack when feasible.

Assessment of the toxicity of firefighter exposures using the PAH CALUX bioassay

Firefighters can be exposed to a complex set of contaminants while at a fire scene. Identifying new ways to monitor and assess exposure, particularly relating to toxicity is essential to determine the effectiveness of intervention techniques to reduce exposure. This study investigated the use of the polycyclic aromatic hydrocarbon (PAH) CALUX® bioassay for the assessment of exposure and associated toxicity firefighters might encounter. This was done through analysis of extracts of dermal wipes and urine samples collected from firefighters before and after a controlled fire. An increased bioassay response was observed from post-fire neck and calf samples, indicating a greater concentration of PAH-like compounds on the skin. The use of a baby wipe to clean the face and neck during rehab resulted in the attenuation of the observed bioassay response from the neck post-fire. Though a correlation was observed between the bioassay response and hydroxylated PAH concentrations found in the urine, the increased bioassay response from the post-fire urine samples was likely due to unknown compounds other than the hydroxylated PAHs tested. Our results suggest that this bioassay provides a useful measure of firefighter exposure, particularly relating to the potential toxicity of contaminants.

Mortality in a cohort of US firefighters from San Francisco, Chicago and Philadelphia: an update

OBJECTIVES

To update the mortality experience of a previously studied cohort of 29 992 US urban career firefighters compared with the US general population and examine exposure-response relationships within the cohort.

METHODS

Vital status was updated through 2016 adding 7 years of follow-up. Cohort mortality compared with the US population was evaluated via life table analyses. Full risk-sets, matched on attained age, race, birthdate and fire department were created and analysed using the Cox proportional hazards regression to examine exposure-response associations between select mortality outcomes and exposure surrogates (exposed-days, fire-runs and fire-hours). Models were adjusted for a potential bias from healthy worker survivor effects by including a categorical variable for employment duration.

RESULTS

Compared with the US population, mortality from all cancers, mesothelioma, non-Hodgkin's lymphoma (NHL) and cancers of the oesophagus, intestine, rectum, lung and kidney were modestly elevated. Positive exposure-response relationships were observed for deaths from lung cancer, leukaemia and chronic obstructive pulmonary disease (COPD).

CONCLUSIONS

This update confirms previous findings of excess mortality from all cancers and several site-specific cancers as well as positive exposure-response relations for lung cancer and leukaemia. New findings include excess NHL mortality compared with the general population and a positive exposure-response relationship for COPD. However, there was no evidence of an association between any quantitative exposure measure and NHL.

Examining Behaviors Related to Retirement, Cleaning, and Storage of Turnout Gear Among Rural Firefighters

Background: Although the increased occupational exposures among career firefighters are well documented, there are gaps in research related to exposures among volunteer firefighters. This study was completed in a state where the majority of firefighters are volunteers. We aimed to examine if differences existed in career versus volunteer firefighters' behaviors related to the retirement, cleaning, and storage of turnout gear which may increase occupational exposures. Methods: A cross-sectional survey was administered to a convenience sample of 300 firefighters during a training event for both volunteer and career firefighters from one fire district in Kentucky. We measured factors that may affect behaviors related to retirement, cleaning, and storage of turnout gear, such as age of turnout gear at retirement, frequency of cleaning, and location of storage. Results: Two hundred and seventy-five firefighters out of 300 invited participants completed the survey, for a response rate of 92%. The majority of the participants were compliant with National Fire Protection Association Standards with most reporting cleaning their gear as needed, storing gear at the fire station, and retiring gear within 10 years of the manufactured date. Most of the participants (88%) were concerned about job-related exposures and felt susceptible to diseases like cancer and respiratory illness. The structural issues of cost and accessibility were identified as the primary barriers to the proper retirement and cleaning of turnout gear, especially among volunteer firefighters. Conclusions/Application to Practice: Most participants retired, cleaned, and stored turnout as recommended. The majority of participants were concerned with job-related exposures. The structural issues of cost and accessibility were identified as the primary barriers to the proper retirement and cleaning of turnout gear, especially among volunteer firefighters. By identifying differences, tailored trainings could be aimed at volunteer firefighters to help reduce their exposures.

Evaluation of the Effect of an Exhaust Reduction System in Fire Stations

Firefighters are known to be exposed to a variety of hazardous materials and combustion products during operational and training activities, as well as in fire stations. However, exposure to diesel exhaust emissions, classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC), is also present in the fire station environment. In this study, concentrations of elemental carbon (EC), which is a surrogate of diesel exhaust and indoor air pollutants, has been measured to compare the effect of an exhaust reduction system (ERS) that was installed in the engine bays of two fire stations to mitigate indoor air pollution levels in the garage, duty offices, and dormitory/shower areas. The levels of most pollutants were reduced after the installation of the ERS. Pollutants may disperse inside of fire stations. Therefore, the ERS is a valuable strategy to mitigate pollutant exposure among firefighters and outdoor air pollution using the filtration ability of an ERS. The results of this study suggest that all truck bays should install an ERS to reduce pollutant exposure and that installation is especially necessary for EURO 3 fire vehicles.

MicroRNA Changes in Firefighters

Objectives:

Firefighters have elevated cancer incidence and mortality rates. MicroRNAs play prominent roles in carcinogenesis, but have not been previously evaluated in firefighters.

Methods:

Blood from 52 incumbent and 45 new recruit nonsmoking firefighters was analyzed for microRNA expression, and the results adjusted for age, obesity, ethnicity, and multiple comparisons.

Results:

Nine microRNAs were identified with at least a 1.5-fold significant difference between groups. All six microRNAs with decreased expression in incumbent firefighters have been reported to have tumor suppressor activity or are associated with cancer survival, and two of the three microRNAs with increased expression in incumbent firefighters have activities consistent with cancer promotion, with the remaining microRNA associated with neurological disease.

Conclusion:

Incumbent firefighters showed differential microRNA expression compared with new recruits, providing potential mechanisms for increased cancer risk in firefighters.

Cancer incidence among Swedish firefighters: an extended follow-up of the NOCCA study

Objectives

To evaluate cancer incidence among Swedish firefighters and analyze risk in relation to work duration as a proxy for cumulative exposure.

Methods

This cohort study is based on the Swedish component of the Nordic Occupational Cancer (NOCCA) project. The cohort includes six million people who participated in one or more of the population censuses in 1960, 1970, 1980 and 1990. The census data were linked to the Swedish Cancer Registry for the 1961–2009 period, extending a previous NOCCA follow-up time by 4 years. We identified 8136 male firefighters. SIRs were calculated using cancer incidence rates in the national population as a reference.

Results

We found a statistically significant excess of non-melanoma skin cancer (SIR = 1.48, 95% CI 1.20–1.80) but no positive relationship between risk and work duration. There was a small, yet statistically significant increased risk of prostate cancer among firefighters with service times of 30 years or more. The first follow-up period (1961–1975) showed an increased risk of stomach cancer relative to the reference group, while the last period (1991–2009) showed an increased risk of non-melanoma skin cancer. There was no excess risk for all cancer sites combined (SIR = 1.03, 95% CI 0.97–1.09).

Conclusions

Our results do not support an overall risk of cancer among Swedish firefighters, but a possible risk of non-melanoma skin cancer exists. The previously noted excess of prostate cancer among Swedish firefighters in NOCCA was no longer statistically significant in this extended follow-up but was present among those with the longest service times.

Examination of Strenuous Activity Preceding Cardiac Death during Firefighting Duties

Sudden cardiac death accounts for approximately 45% of duty-related fatalities among United States firefighters. Strenuous physical exertion is recognized as a trigger of sudden cardiac events. This study describes the duration of strenuous physical exertion on-scene preceding a fatal cardiac event by situation encountered during firefighting duties. Data provided by the National Institute for Occupational Safety and Health Fire Fighter Fatality Investigation and Prevention Program for duty-related firefighter fatalities over a 9-year period were analyzed. Among the 235 fatalities investigated, 45% had a cause of death that was cardiac in origin. Time (mean ± SD) spent on-scene in strenuous work was 30 ± 26 min, 14 ± 15 min, and 47 ± 52 min for fire, non-fire emergency, and training situations, respectively. Across all emergency operations and training, 31% of fatalities occurred among firefighters who performed ≤10 min of strenuous work, whereas 13% of fatalities occurred among those who performed >60 min. Study findings indicate that there is considerable variability in the duration of strenuous work preceding fatal cardiac events during firefighting duties. Notably, a high percentage of fatal cardiac events occurred after a relatively brief period of strenuous work, suggesting that the performance of any strenuous work, even that of short duration, may be sufficient to provoke a cardiac event in a firefighter with underlying cardiac disease.

Understanding airborne contaminants produced by different fuel packages during training fires

Fire training may expose firefighters and instructors to hazardous airborne chemicals that vary by the training fuel. We conducted area and personal air sampling during three instructional scenarios per day involving the burning of two types (designated as alpha and bravo) of oriented strand board (OSB), pallet and straw, or the use of simulated smoke, over a period of 5 days. Twenty-four firefighters and ten instructors participated. Firefighters participated in each scenario once (separated by about 48 hr) and instructors supervised three training exercise per scenarios (completed in 1 day). Personal air samples were analyzed for polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and hydrogen cyanide during live-fire scenarios (excluding simulated smoke). Area air samples were analyzed for acid gases, aldehydes, isocyanates, and VOCs for all scenarios. For the live-fire scenarios, median personal air concentrations of benzene and PAHs exceeded applicable short-term exposure limits and were higher among firefighters than instructors. When comparing results by type of fuel, personal air concentrations of benzene and PAHs were higher for bravo OSB compared to other fuels. Median area air concentrations of aldehydes and isocyanates were also highest during the bravo OSB scenario, while pallet and straw produced the highest median concentrations of certain VOCs and acid gases. These results suggest usage of self-contained breathing apparatus (SCBA) by both instructors and firefighters is essential during training fires to reduce potential inhalation exposure. Efforts should be taken to clean skin and clothing as soon as possible after live-fire training to limit dermal absorption as well.

Firefighters' and instructors’ absorption of PAHs and benzene during training exercises

Introduction:

Training fires may constitute a major portion of some firefighters’ occupational exposures to smoke. However, the magnitude and composition of those exposures are not well understood and may vary by the type of training scenario and fuels.

Objectives:

To understand how structure fire training contributes to firefighters’ and instructors’ select chemical exposures, we conducted biological monitoring during exercises involving combustion of pallet and straw and oriented strand board (OSB) or the use of simulated smoke.

Methods:

Urine was analyzed for metabolites of polycyclic aromatic hydrocarbons (PAHs) and breath was analyzed for volatile organic compounds (VOCs) including benzene.

Results:

Median concentrations of nearly all PAH metabolites in urine increased from pre-to 3-hr post-training for each scenario and were highest for OSB, followed by pallet and straw, and then simulated smoke. For instructors who supervised three trainings per day, median concentrations increased at each collection. A single day of OSB exercises led to a 30-fold increase in 1-hydroxypyrene for instructors, culminating in a median endof-shift concentration 3.5-fold greater than median levels measured from firefighters in a previous controlledresidential fire study. Breath concentrations of benzene increased 2 to 7-fold immediately after the training exercises (with the exception of simulated smoke training). Exposures were highest for the OSB scenario and instructors accumulated PAHs with repeated daily exercises.

Conclusions:

Dermal absorption likely contributed to the biological levels as the respiratory route was well protected. Training academies should consider exposure risks as well as instructional objectives when selecting training exercises.

Wildland firefighter smoke exposure and risk of lung cancer and cardiovascular disease mortality

Wildland firefighters are exposed to wood smoke, which contains hazardous air pollutants, by suppressing thousands of wildfires across the U. S. each year. We estimated the relative risk of lung cancer and cardiovascular disease mortality from existing PM_2.5 exposure-response relationships using measured PM₄ concentrations from smoke and breathing rates from wildland firefighter field studies across different exposure scenarios. To estimate the relative risk of lung cancer (LC) and cardiovascular disease (CVD) mortality from exposure to PM_2.5 from smoke, we used an existing exposure-response (ER) relationship. We estimated the daily dose of wildfire smoke PM_2.5 from measured concentrations of PM₄, estimated wildland firefighter breathing rates, daily shift duration (hours per day) and frequency of exposure (fire days per year and career duration). Firefighters who worked 49 days per year were exposed to a daily dose of PM₄ that ranged from 0.15 mg to 0.74 mg for a 5- and 25-year career, respectively. The daily dose for firefighters working 98 days per year of PM₄ ranged from 0.30 mg to 1.49 mg. Across all exposure scenarios (49 and 98 fire days per year) and career durations (5-25 years), we estimated that wildland firefighters were at an increased risk of LC (8 percent to 43 percent) and CVD (16 percent to 30 percent) mortality. This unique approach assessed long term health risks for wildland firefighters and demonstrated that wildland firefighters have an increased risk of lung cancer and cardiovascular disease mortality.

DNA methylation among firefighters

Firefighters are exposed to carcinogens and have elevated cancer rates. We hypothesized that occupational exposures in firefighters would lead to DNA methylation changes associated with activation of cancer pathways and increased cancer risk. To address this hypothesis, we collected peripheral blood samples from 45 incumbent and 41 new recruit non-smoking male firefighters and analyzed the samples for DNA methylation using an Illumina Methylation EPIC 850k chip. Adjusting for age and ethnicity, we performed: 1) genome-wide differential methylation analysis; 2) genome-wide prediction for firefighter status (incumbent or new recruit) and years of service; and 3) Ingenuity Pathway Analysis (IPA). Four CpGs, including three in the YIPF6, MPST, and PCED1B genes, demonstrated above 1.5-fold statistically significant differential methylation after Bonferroni correction. Genome-wide methylation predicted with high accuracy incumbent and new recruit status as well as years of service among incumbent firefighters. Using IPA, the top pathways with more than 5 gene members annotated from differentially methylated probes included Sirtuin signaling pathway, p53 signaling, and 5' AMP-activated protein kinase (AMPK) signaling. These DNA methylation findings suggest potential cellular mechanisms associated with increased cancer risk in firefighters.

Firefighter hood contamination: Efficiency of laundering to remove PAHs and FRs

Firefighters are occupationally exposed to products of combustion containing polycyclic aromatic hydrocarbons (PAHs) and flame retardants (FRs), potentially contributing to their increased risk for certain cancers. Personal protective equipment (PPE), including firefighter hoods, helps to reduce firefighters' exposure to toxic substances during fire responses by providing a layer of material on which contaminants deposit prior to reaching the firefighters skin. However, over time hoods that retain some contamination may actually contribute to firefighters' systemic dose. We investigated the effectiveness of laundering to reduce or remove contamination on the hoods, specifically PAHs and three classes of FRs: polybrominated diphenyl ethers (PBDEs), non-PBDE flame retardants (NPBFRs), and organophosphate flame retardants (OPFRs). Participants in the study were grouped into crews of 12 firefighters who worked in pairs by job assignment while responding to controlled fires in a single-family residential structure. For each pair of firefighters, one hood was laundered after every scenario and one was not. Bulk samples of the routinely laundered and unlaundered hoods from five pairs of firefighters were collected and analyzed. Residual levels of OPFRs, NPBFRs, and PAHs were lower in the routinely laundered hoods, with total levels of each class of chemicals being 56-81% lower, on average, than the unlaundered hoods. PBDEs, on average, were 43% higher in the laundered hoods, most likely from cross contamination. After this initial testing, four of the five unlaundered exposed hoods were subsequently laundered with other heavily exposed (unlaundered) and unexposed (new) hoods. Post-laundering evaluation of these hoods revealed increased levels of PBDEs, NPBFRs, and OPFRs in both previously exposed and unexposed hoods, indicating cross contamination. For PAHs, there was little evidence of cross contamination and the exposed hoods were significantly less contaminated after laundering (76% reduction; p = 0.011). Further research is needed to understand how residual contamination on hoods could contribute to firefighters' systemic exposures.

The Invisible Danger of Transferring Toxins with Bunker Gear: A Theory-Based Intervention to Increase Postfire Decontamination to Reduce Cancer Risk in Firefighters

Studies show significant association between cancer risk and being a firefighter. After exposure to even routine firefighting, firefighters' bunker gear often contains carcinogens that may be absorbed through contact or inhaled through off-gassing, thereby increasing cancer risk. Awareness of increased cancer risk has given rise to policies and practices focused on gear cleaning and decontamination processes to decrease risk; yet, these efforts are in their infancy and tend to be somewhat piecemeal in nature. This study presents a theory-based communication intervention tailored to the unique context of high-reliability organizations (HROs). The intervention focused on increasing postfire decontamination behaviors to reduce exposure to carcinogens among firefighters. Results of the intervention across 14 fire stations from 2 fire departments in South Florida show significant increases in attitudes, norms, and self-efficacy, decreases in perceived barriers, and increased intention to engage in decontamination processes. While the intervention was highly successful in both fire departments, there were significant differences in between organizations; attitudes perceived norms, and barriers to gear cleaning remained significantly different. This highlights the need to examine the specific context of the organization in designing interventions. In line with previous research on HROs, regression models showed that norms and self-efficacy are the strongest predictors of current behavior. However, postintervention, attitudes emerge as the strongest predictor of future behavior. The results of this study provide valuable evidence for utilizing theoretical elements in message design for interventions in HROs, and of the importance of designing communication for specific sites of intervention.

Prevalence and Correlates of Late Initiation of Smokeless Tobacco in US Firefighters

Introduction

Prevalence rates of smokeless tobacco (SLT) use and late initiation among firefighters (ie, starting use as an adult after joining the fire service) are remarkably high, 10.5% and 26.0%, respectively. The purpose of this study is to examine characteristics associated with late SLT initiation in a sample comprised of male career firefighters from two large cohort studies.

Methods

We examined correlates of late SLT initiation in a secondary analysis of data combining the baseline evaluations of two published firefighter health studies with 1474 male career firefighters in the United States.

Results

Fourteen percent of participants were current SLT users. Among this group, the unadjusted rate of firefighters who initiated SLT use after joining the fire service was 15.9%, while the age-standardized rate was 38.2%; this is substantially higher than the national adjusted late initiation rate among adult males (0.8%). In addition, firefighters demonstrated higher rates of late SLT initiation (15.9% unadjusted; 18.4% age-standardized) when compared to males in the military overall (13.8%).

Conclusions

The exceptionally high prevalence of SLT use overall and late initiation in the fire service suggest that joining the fire service in the United States is a risk factor for SLT use. There is a need to develop interventions aimed at reducing SLT use in the fire service that are specifically tailored for this occupational group.

Implications

The high prevalence of late SLT initiation (ie, starting use as an adult after joining the fire service) among firefighters should be addressed by both researchers and fire service organizations given the significant health risks associated with SLT and its impact on occupational readiness. There is a need for developing intervention programs aimed at reducing SLT use in the fire service. Interventions would need to be specifically tailored for this occupational group and their unique culture, given that joining the fire service appears to be a risk factor for SLT initiation among firefighters who did not use tobacco prior to joining the fire service.

Airborne contaminants during controlled residential fires

In this study, we characterize the area and personal air concentrations of combustion byproducts produced during controlled residential fires with furnishings common in 21^st century single family structures. Area air measurements were collected from the structure during active fire and overhaul (post suppression) and on the fireground where personnel were operating without any respiratory protection. Personal air measurements were collected from firefighters assigned to fire attack, victim search, overhaul, outside ventilation, and command/pump operator positions. Two different fire attack tactics were conducted for the fires (6 interior and 6 transitional) and exposures were compared between the tactics. For each of the 12 fires, firefighters were paired up to conduct each job assignment, except for overhaul that was conducted by 4 firefighters. Sampled compounds included polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs, e.g., benzene), hydrogen cyanide (HCN), and particulate (area air sampling only). Median personal air concentrations for the attack and search firefighters were generally well above applicable short-term occupational exposure limits, with the exception of HCN measured from search firefighters. Area air concentrations of all measured compounds decreased after suppression. Personal air concentrations of total PAHs and benzene measured from some overhaul firefighters exceeded exposure limits. Median personal air concentrations of HCN (16,300 ppb) exceeded the exposure limit for outside vent firefighters, with maximum levels (72,900 ppb) higher than the immediately dangerous to life and health (IDLH) level. Median air concentrations on the fireground (including particle count) were above background levels and highest when collected downwind of the structure and when ground-level smoke was the heaviest. No statistically significant differences in personal air concentrations were found between the 2 attack tactics. The results underscore the importance of wearing self-contained breathing apparatus when conducting overhaul or outside ventilation activities. Firefighters should also try to establish command upwind of the structure fire, and if this cannot be done, respiratory protection should be considered.

Organophosphate flame retardants in dust collected from United States fire stations

Firefighters are exposed to chemicals during fire events and we previously demonstrated that fire station dust has high levels of polybrominated diphenyl ethers (PBDEs). In conducting the Fire Station Dust Study, we sought to further characterize the chemicals to which firefighters could be exposed - measuring the emerging class of phosphorous-containing flame retardants (PFRs) in fire stations, for the first time, as well as PBDEs. Dust samples from 26 fire stations in five states were collected from vacuum-cleaner bags and analyzed for PFRs and PBDEs. PFR concentrations were found to be on the same order of magnitude as PBDE concentrations (maximum PFR: 218,000ng/g; maximum PBDE: 351,000ng/g). Median concentrations of tri-n-butyl phosphate (TNBP), tris (2-chloroisopropyl) phosphate (TCIPP), and tris(1,3-dichloroisopropyl)phosphate (TDCIPP) in dust from fire stations were higher than those previously reported in homes and other occupational settings around the world. Total PFR levels did not vary significantly among states. Levels of TDCIPP were higher in stations where vacuum cleaners were used to clean surfaces other than the floor. PBDE levels were comparable to those found in our previous study of 20 California fire stations and much higher than levels in California residences. PFR and PBDE levels in fire station dust are higher than in other occupational and residential settings, underscoring the need to identify and control sources of this contamination.

Occupational Exposure to Polycyclic Aromatic Hydrocarbons and Elevated Cancer Incidence in Firefighters

Cancer incidence appears to be higher amongst firefighters compared to the general population. Given that many cancers have an environmental component, their occupational exposure to products of carbon combustion such as polycyclic aromatic hydrocarbons (PAHs) is of concern. This is the first UK study identifying firefighters exposure to PAH carcinogens. Wipe samples were collected from skin (jaw, neck, hands), personal protective equipment of firefighters, and work environment (offices, fire stations and engines) in two UK Fire and Rescue Service Stations. Levels of 16 US Environmental Protection Agency (EPA) PAHs were quantified together with more potent carcinogens: 7,12-dimethylbenzo[a]anthracene, and 3-methylcholanthrene (3-MCA) (12 months post-initial testing). Cancer slope factors, used to estimate cancer risk, indicate a markedly elevated risk. PAH carcinogens including benzo[a]pyrene (B[a]P), 3-MCA, and 7,12-dimethylbenz[a]anthracene PAHs were determined on body surfaces (e.g., hands, throat), on PPE including helmets and clothing, and on work surfaces. The main exposure route would appear to be via skin absorption. These results suggest an urgent need to monitor exposures to firefighters in their occupational setting and conduct long-term follow-up regarding their health status.

Perceptions of health and cancer risk among newly recruited firefighters in South Florida

PURPOSE

Despite hazardous exposures to cancer-causing agents in the line of duty, the main health and safety concerns of active firefighters have yet to be studied. We compare the perceptions of health and cancer risks between rookie and experienced firefighters.

METHODS

Focus groups were used to investigate potential risk of job exposures, and broad-based concerns regarding work and health. An 18-item demographic survey was also administered. Five focus group sessions were conducted with a total of 57 firefighters.

RESULTS

Our findings indicate that both rookie and experienced firefighters have a "high risk, high reward" mindset and identify injury, chronic disease, and stress as main health concerns. Experienced firefighters reported a shift in firefighter culture related to health.

CONCLUSION

The perception of health and cancer risk of rookie and experienced firefighters differ in the prioritization of their concerns, however both groups equally report occupational cancer risk as their main health concern.

Prostate cancer in firefighting and police work: a systematic review and meta-analysis of epidemiologic studies

OBJECTIVES

We conducted a systematic review and meta-analysis to evaluate potential associations between firefighting and police occupations, and prostate cancer incidence and mortality.

METHODS

Original epidemiological studies published from 1980 to 2017 were identified through PubMed and Web of Science. Studies were included if they contained specific job titles for ever/never firefighting and police work and associated prostate cancer risk estimates with 95% confidence intervals (CI). Study quality was assessed using a 20-point checklist. Prostate cancer meta-risk estimates (mRE) and corresponding 95% CIs were calculated for firefighting and police work separately and by various study characteristics using random effects models. Between-study heterogeneity was evaluated using the I² score. Publication bias was assessed using Begg's and Egger's tests.

RESULTS

A total of 26 firefighter and 12 police studies were included in the meta-analysis, with quality assessment scores ranging from 7 to 19 points. For firefighter studies, the prostate cancer incidence mRE was 1.17 (95% CI = 1.08-1.28, I² = 72%) and the mortality mRE was 1.12 (95% CI = 0.92-1.36, I² = 50%). The mRE for police incidence studies was 1.14 (95% CI = 1.02-1.28; I² = 33%); for mortality studies, the mRE was 1.08 (95% CI = 0.80-1.45; I² = 0%). By study design, mREs for both firefighter and police studies were similar to estimates of incidence and mortality.

CONCLUSION

Small excess risks of prostate cancer were observed from firefighter studies with moderate to substantial heterogeneity and a relatively small number of police studies, respectively. There is a need for further studies to examine police occupations and to assess unique and shared exposures in firefighting and police work.

Long-term follow-up for cancer incidence in a cohort of Danish firefighters

Objectives

To examine cancer incidence among Danish firefighters using several employment-related exposure subgroups.

Methods

A historical cohort of 9061 male Danish firefighters was established from collected personnel and membership records from employers and trade unions. Using the unique Danish personal identification number, information on additional previous employment, cancer and vital status was linked to members of the cohort from the Supplementary Pension Fund Register, the Danish Cancer Registry and the Danish Civil Registration System. SIRs were calculated for specific cancer types using rates for the general population, a sample of the working population and military employees, respectively.

Results

Compared with the selected reference groups, the overall observed incidence of cancer among the firefighters was at level with the expected (SIR 1.02, 95% CI 0.96 to 1.09 vs the general population). The SIR for colon cancer was consistently significantly reduced, while the slight excess seen for melanoma of the skin, prostate and testicular cancer compared with the general population was not reproduced using the military as reference.

Conclusions

Previous associations with melanoma of the skin, prostate and testicular cancer are supported by our main results. However, the increase in incidence of these cancers is not reproduced using the military as reference. Similarities in cancer profile for the firefighters and the military point to shared risk factors in either lifestyle or work environment.

Assessment of Ambient Exposures Firefighters Encounter While at the Fire Station: An Exploratory Study

OBJECTIVE

Firefighters are at an increased risk for many types of cancer. Although most studies on this topic focus on exposures encountered while fighting fires, exposures at the fire station are also cause for concern. This pilot study aimed to describe air quality within a few fire stations in and around Boston, Massachusetts, and to investigate physical and organizational factors that may influence levels of contaminants in stations.

METHODS

Air sampling of particulate matter less than 2.5 μm in diameter (PM2.5) and particle-bound polycyclic aromatic hydrocarbons (PAHs) was completed at four fire stations in Spring, 2016. Sampling occurred in the kitchen, truck bay, and just outside the station. Data were analyzed to assess differences between and within stations. Interviews (n =7) were conducted with officers at each station to explore health and safety-related organizational policies and practices. Interviews were transcribed and analyzed for thematic content.

RESULTS

At each station, levels of contaminants were higher in the truck bays than either the outdoors or kitchen, and varied the most throughout the day. The station with the highest exposures in the truck bay had the lowest levels in the kitchen, which was possibly explained by new building materials and effective separation between building zones. The age and layout of the stations appeared to determine the extent to which policies favoring exhaust capture were implemented.

CONCLUSION

Levels of PM2.5 and PAH inside fire stations may contribute to firefighter cancer risk. Through understanding contaminant variability, we can begin to design and test interventions that improve cancer prevention.

Contamination of firefighter personal protective equipment and skin and the effectiveness of decontamination procedures

Firefighters' skin may be exposed to chemicals via permeation/penetration of combustion byproducts through or around personal protective equipment (PPE) or from the cross-transfer of contaminants on PPE to the skin. Additionally, volatile contaminants can evaporate from PPE following a response and be inhaled by firefighters. Using polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) as respective markers for non-volatile and volatile substances, we investigated the contamination of firefighters' turnout gear and skin following controlled residential fire responses. Participants were grouped into three crews of twelve firefighters. Each crew was deployed to a fire scenario (one per day, four total) and then paired up to complete six fireground job assignments. Wipe sampling of the exterior of the turnout gear was conducted pre- and post-fire. Wipe samples were also collected from a subset of the gear after field decontamination. VOCs off-gassing from gear were also measured pre-fire, post-fire, and post-decon. Wipe sampling of the firefighters' hands and neck was conducted pre- and post-fire. Additional wipes were collected after cleaning neck skin. PAH levels on turnout gear increased after each response and were greatest for gear worn by firefighters assigned to fire attack and to search and rescue activities. Field decontamination using dish soap, water, and scrubbing was able to reduce PAH contamination on turnout jackets by a median of 85%. Off-gassing VOC levels increased post-fire and then decreased 17-36 min later regardless of whether field decontamination was performed. Median post-fire PAH levels on the neck were near or below the limit of detection (< 24 micrograms per square meter [µg/m²]) for all positions. For firefighters assigned to attack, search, and outside ventilation, the 75^th percentile values on the neck were 152, 71.7, and 39.3 µg/m², respectively. Firefighters assigned to attack and search had higher post-fire median hand contamination (135 and 226 µg/m², respectively) than other positions (< 10.5 µg/m²). Cleansing wipes were able to reduce PAH contamination on neck skin by a median of 54%.

Occupation and risk of prostate cancer in Canadian men: A case-control study across eight Canadian provinces

BACKGROUND

The etiology of prostate cancer continues to be poorly understood, including the role of occupation. Past Canadian studies have not been able to thoroughly examine prostate cancer by occupation with detailed information on individual level factors.

METHODS

Occupation, industry and prostate cancer were examined using data from the National Enhanced Cancer Surveillance System, a large population-based case-control study conducted across eight Canadian provinces from 1994 to 1997. This analysis included 1737 incident cases and 1803 controls aged 50 to 79 years. Lifetime occupational histories were used to group individuals by occupation and industry employment. Odds ratios and 95% confidence intervals were calculated and adjustments were made for known and possible risk factors.

RESULTS

By occupation, elevated risks were observed in farming and farm management (OR=1.37, 95% CI 1.02-1.84), armed forces (OR=1.33, 95% CI 1.06-1.65) and legal work (OR=2.58, 95% CI 1.05-6.35). Elevated risks were also observed in office work (OR=1.20, 95% CI 1.00-1.43) and plumbing (OR=1.77, 95% CI 1.07-2.93) and with ≥10 years duration of employment. Decreased risks were observed in senior management (OR=0.65, 95% CI 0.46-0.91), construction management (OR=0.69, 95% CI 0.50-0.94) and travel work (OR=0.37, 95% CI 0.16-0.88). Industry results were similar to occupation results, except for an elevated risk in forestry/logging (OR=1.54, 95% CI 1.06-2.25) and a decreased risk in primary metal products (OR=0.70, 95% CI 0.51-0.96).

CONCLUSION

This study presents associations between occupation, industry and prostate cancer, while accounting for individual level factors. Further research is needed on potential job-specific exposures and screening behaviours.

Lung Cancer Among Firefighters: Smoking-Adjusted Risk Estimates in a Pooled Analysis of Case-Control Studies

OBJECTIVES

The aim of this study was to explore lung cancer risk among firefighters, with adjustment for smoking.

METHODS

We used pooled information from the SYNERGY project including 14 case-control studies conducted in Europe, Canada, New Zealand, and China, with lifetime work histories and smoking habits for 14,748 cases of lung cancer and 17,543 controls. We estimated odds ratios by unconditional logistic regression with adjustment for smoking and having ever been employed in a job known to present an excess risk of lung cancer.

RESULTS

There was no increased lung cancer risk overall or by specific cell type among firefighters (n = 190), neither before nor after smoking adjustment. We observed no significant exposure-response relationship in terms of work duration.

CONCLUSIONS

We found no evidence of an excess lung cancer risk related to occupational exposure as a firefighter.

Risk of cancer among firefighters in California, 1988-2007

BACKGROUND

Most studies of firefighter cancer risks were conducted prior to 1990 and do not reflect risk from advances in building materials.

METHODS

A case-control study using California Cancer Registry data (1988-2007) was conducted to evaluate the risk of cancer among firefighters, stratified by race.

RESULTS

This study identified 3,996 male firefighters with cancer. Firefighters were found to have a significantly elevated risk for melanoma (odds ratio [OR] = 1.8; 95% confidence interval [CI] 1.4-2.1), multiple myeloma (OR 1.4; 95%CI 1.0-1.8), acute myeloid leukemia (OR 1.4; 95%CI 1.0-2.0), and cancers of the esophagus (OR 1.6; 95%CI 1.2-2.1), prostate (OR 1.5; 95%CI 1.3-1.7), brain (OR 1.5; 95%CI 1.2-2.0), and kidney (OR 1.3; 95%CI 1.0-1.6).

CONCLUSIONS

In addition to observing cancer findings consistent with previous research, this study generated novel findings for firefighters with race/ethnicity other than white. It provides additional evidence to support the association between firefighting and several specific cancers.