Exposure to a firefighting overhaul environment without respiratory protection increases immune dysregulation and lung disease risk

"Air That Once Was Breath" Part 2: Wildfire Smoke and Airway Disease - "Climate Change, Allergy and Immunology" Special IAAI Article Collection: Collegium Internationale Allergologicum Update 2023

BACKGROUND

Population growth and climate change have led to more frequent and larger wildfires, increasing the exposure of individuals to wildfire smoke. Notably, asthma exacerbations and allergic airway sensitization are prominent outcomes of such exposure.

SUMMARY

Key research questions relate to determining the precise impact on individuals with asthma, including the severity, duration, and long-term consequences of exacerbations. Identifying specific risk factors contributing to vulnerability, such as age, genetics, comorbidities, or environmental factors, is crucial. Additionally, reliable biomarkers for predicting severe exacerbations need exploration. Understanding the long-term health effects of repeated wildfire smoke exposures in individuals with asthma and addressing healthcare disparities are important research areas.

KEY MESSAGES

This review discusses the need for comprehensive research efforts to better grasp wildfire smoke-induced respiratory health, particularly in vulnerable populations such as farmworkers, firefighters, pregnant women, children, the elderly, and marginalized communities. Effective mitigation would require addressing the current limitations we face by supporting research aimed at a better understanding of wildfire smoke-induced airway disease.

Wildland fire, air pollution and cardiovascular health: is it time to focus on the microvasculature as a risk assessment tool?

Climate change favors weather conditions conducive to wildland fires. The intensity and frequency of forest fires are increasing, and fire seasons are lengthening. Exposure of human populations to smoke emitted by these fires increases, thereby contributing to airborne pollution through the emission of gas and particulate matter (PM). The adverse health outcomes associated with wildland fire exposure represent an important burden on the economies and health systems of societies. Even though cardiovascular diseases (CVDs) are the main of cause of the global burden of diseases attributable to PM exposure, it remains difficult to show reliable associations between exposure to wildland fire smoke and cardiovascular disease risk in population-based studies. Optimal health requires a resilient and adaptable network of small blood vessels, namely, the microvasculature. Often alterations of this microvasculature precede the occurrence of adverse health outcomes, including CVD. Biomarkers of microvascular health could then represent possible markers for the early detection of poor cardiovascular outcomes. This review aims to synthesize the current literature to gauge whether assessing the microvasculature can better estimate the cardiovascular impact of wildland fires.

Cancer and Potential Prevention with Lifestyle among Career Firefighters: A Narrative Review

Career firefighters are at considerable risk for chronic diseases, including an increased risk of various cancers, compared to the general population. Over the last two decades, several systematic reviews and large cohort studies have demonstrated that firefighters have statistically significant increases in overall and site-specific cancer incidence and site-specific cancer mortality compared to the general population. Exposure assessment and other studies have documented exposures to a variety of carcinogens in fire smoke and within the fire station. Other occupational factors such as shift work, sedentary behavior, and the fire service food culture may also contribute to this working population's increased cancer risk. Furthermore, obesity and other lifestyle behaviors such as tobacco use, excessive alcohol consumption, poor diet, inadequate physical activity, and short sleep duration have also been associated with an increased risk of certain firefighting-associated cancers. Putative prevention strategies are proposed based on suspected occupational and lifestyle risk factors.

Interaction and effects of dangerous and hidden points on firefighter’s health during fire overhaul using the PLS-SEM technique

Purpose

The existence of hidden and dangerous points after the fire leads to loss of command of the rescue teams, casualties, and financial loss. This paper aims to identify these points by taking into account their contributing factors that can help to better manage, prevent and prepare for the risks even after their occurrence.

Design/methodology/approach

In this study, the fire overhaul was investigated by identifying the risks of this stage and ranking them in terms of impact. This paper introduces danger points using empirical knowledge (questionnaire) along with theoretical knowledge (literature review) and suggested solutions. Finally, by investigating the dangers and their effects on each other, it introduced three main danger paths. The main problem is the lack of applied knowledge, the relationship between theoretical knowledge at this stage of fire and its application in firefighting operations. To solve this problem, a model was developed to determine the relationships between the effects on firefighters’ health during fire overhaul using structural equation modeling (SEM) in the building. To develop this model, dangerous points were first identified, categorized and weighted, and then the effect of each of these points and their interactions was determined.

Findings

This paper contributes to the literature by identifying hazardous points and investigating their impacts on firefighters’ health using the SEM method. This study identifies 17 points that can be traversed through three paths.

Research limitations/implications

Hazardous points could affect the success of the fire overhaul operation. Adopting a flexible model during this stage can enhance safety.

Originality/value

The results of this study can be used to rank and classify fire overhaul hazards in buildings and to increase firefighters’ safety and other related factors.

Hierarchy of contamination control in the fire service: Review of exposure control options to reduce cancer risk

The international fire service community is actively engaged in a wide range of activities focused on development, testing, and implementation of effective approaches to reduce exposure to contaminants and the related cancer risk. However, these activities are often viewed independent of each other and in the absence of the larger overall effort of occupational health risk mitigation. This narrative review synthesizes the current research on fire service contamination control in the context of the National Institute for Occupational Safety and Health (NIOSH) Hierarchy of Controls, a framework that supports decision making around implementing feasible and effective control solutions in occupational settings. Using this approach, we identify evidence-based measures that have been investigated and that can be implemented to protect firefighters during an emergency response, in the fire apparatus and at the fire station, and identify several knowledge gaps that remain. While a great deal of research and development has been focused on improving personal protective equipment for the various risks faced by the fire service, these measures are considered less effective. Administrative and engineering controls that can be used during and after the firefight have also received increased research interest in recent years. However, less research and development have been focused on higher level control measures such as engineering, substitution, and elimination, which may be the most effective, but are challenging to implement. A comprehensive approach that considers each level of control and how it can be implemented, and that is mindful of the need to balance contamination risk reduction against the fire service mission to save lives and protect property, is likely to be the most effective.

The Wildland Firefighter Exposure and Health Effect (WFFEHE) Study: Rationale, Design, and Methods of a Repeated-Measures Study

The wildland firefighter exposure and health effect (WFFEHE) study was a 2-year repeated-measures study to investigate occupational exposures and acute and subacute health effects among wildland firefighters. This manuscript describes the study rationale, design, methods, limitations, challenges, and lessons learned. The WFFEHE cohort included fire personnel ages 18-57 from six federal wildland firefighting crews in Colorado and Idaho during the 2018 and 2019 fire seasons. All wildland firefighters employed by the recruited crews were invited to participate in the study at preseason and postseason study intervals. In 2019, one of the crews also participated in a 3-day midseason study interval where workplace exposures and pre/postshift measurements were collected while at a wildland fire incident. Study components assessed cardiovascular health, pulmonary function and inflammation, kidney function, workplace exposures, and noise-induced hearing loss. Measurements included self-reported risk factors and symptoms collected through questionnaires; serum and urine biomarkers of exposure, effect, and inflammation; pulmonary function; platelet function and arterial stiffness; and audiometric testing. Throughout the study, 154 wildland firefighters participated in at least one study interval, while 144 participated in two or more study interval. This study was completed by the Centers for Disease Control and Prevention's National Institute for Occupational Safety and Health through a collaborative effort with the U.S. Department of Agriculture Forest Service, Department of the Interior National Park Service, and Skidmore College. Conducting research in the wildfire environment came with many challenges including collecting study data with study participants with changing work schedules and conducting study protocols safely and operating laboratory equipment in remote field locations. Forthcoming WFFEHE study results will contribute to the scientific evidence regarding occupational risk factors and exposures that can impact wildland firefighter health over a season and across two wildland fire seasons. This research is anticipated to lead to the development of preventive measures and policies aimed at reducing risk for wildland firefighters and aid in identifying future research needs for the wildland fire community.

Examination of Factors Influencing SCBA Washing Behavior among Firefighters in Metropolitan

Field-washing decontamination of equipment is an effective way for firefighters to reduce their risk of secondary contamination. No study has yet clarified the factors influencing effective field decontamination of equipment such as self-contained breathing apparatuses (SCBAs). This study sought to examine factors that influence the SCBA washing and decontamination behavior of firefighters. We conducted a questionnaire using the web-based Seoul Metropolitan Electronic Questionnaire System. As of May 2021, the survey had been sent to 3626 of 7198 Seoul career firefighters, and 1940 subjects were selected to participate in the study. Binomial logistic regression and χ2-test analyses were performed. We confirmed that previous training in SCBA washing was an important factor in effective field decontamination of SCBAs. Firefighters should be trained to perform field decontamination procedures systematically and regulations to perform field decontamination before leaving the scene of a fire should be introduced.

Airborne contamination during post-fire investigations: Hot, warm and cold scenes

Fire investigators may be occupationally exposed to many of the same compounds as the more widely studied fire suppression members of the fire service but are often tasked with working in a given exposure for longer periods ranging from hours to multiple days and may do so with limited personal protective equipment. In this study, we characterize the area air concentrations of contaminants during post-fire investigation of controlled residential fires with furnishings common to current bedroom, kitchen and living room fires in the United States. Area air sampling was conducted during different investigation phases including when investigations might be conducted immediately after fire suppression and extended out to 5 days after the fire. Airborne particulate over a wide range of dimensions, including sub-micron particles, were elevated to potentially unhealthy levels (based on air quality index) when averaged over a 60 min investigation period shortly after fire suppression with median PM2.5 levels over 100 µg/m³ (range 16-498 µg/m³) and median peak transient concentrations of 1,090 µg/m³ (range 200-23,700 µg/m³) during drywall removal or shoveling activities. Additionally, airborne aldehyde concentrations were elevated compared to volatile organic compounds with peak values of formaldehyde exceeding NIOSH ceiling limits during the earliest investigation periods (median 356 µg/m³, range: 140-775 µg/m³) and occasionally 1 day post-fire when the structure was boarded up before subsequent investigation activities. These results highlight the need to protect investigators' airways from particulates when fire investigation activities are conducted as well as during post-fire reconstruction activities. Additionally, vapor protection from formaldehyde should be strongly considered at least through investigations occurring 3 days after the fire and personal formaldehyde air monitoring is recommended during investigations.

Associations between polyfluoroalkyl substance and organophosphate flame retardant exposures and telomere length in a cohort of women firefighters and office workers in San Francisco

BACKGROUND

Environmental chemical exposures can affect telomere length, which in turn has been associated with adverse health outcomes including cancer. Firefighters are occupationally exposed to many hazardous chemicals and have higher rates of certain cancers. As a potential biomarker of effect, we assessed associations between chemical exposures and telomere length in women firefighters and office workers from San Francisco, CA.

METHODS

We measured serum concentrations of polyfluoroalkyl substances (PFAS), urinary metabolites of flame retardants, including organophosphate flame retardants (OPFRs), and telomere length in peripheral blood leukocytes in women firefighters (N = 84) and office workers (N = 79) who participated in the 2014-15 Women Workers Biomonitoring Collaborative. Multiple linear regression models were used to assess associations between chemical exposures and telomere length.

RESULTS

Regression results revealed significant positive associations between perfluorooctanoic acid (PFOA) and telomere length and perfluorooctanesulfonic acid (PFOS) and telomere length among the whole cohort. Models stratified by occupation showed stronger and more significant associations among firefighters as compared to office workers. Among firefighters in models adjusted for age, we found positive associations between telomere length and log-transformed PFOA (β (95%CI) = 0.57(0.12, 1.02)), PFOS (0.44 (0.05, 0.83)), and perfluorodecanoic acid (PFDA) (0.43 (0.02, 0.84)). Modeling PFAS as categories of exposure showed significant associations between perfluorononanoic acid (PFNA) and telomere length among firefighters. Significant associations between OPFR metabolites and telomere length were seen for bis (1,3-dichloro-2-propyl) phosphate (BDCPP) and telomere length among office workers (0.21(0.03, 0.40)) and bis (2-chloroethyl) phosphate (BCEP) and telomere length among firefighters (- 0.14(- 0.28, - 0.01)). For OPFRs, the difference in the direction of effect by occupational group may be due to the disparate detection frequencies and concentrations of exposure between the two groups and/or potential unmeasured confounding.

CONCLUSION

Our findings suggest positive associations between PFAS and telomere length in women workers, with larger effects seen among firefighters as compared to office workers. The OPFR metabolites BDCPP and BCEP are also associated with telomere length in firefighters and office workers. Associations between chemical exposures and telomere length reported here and by others suggest mechanisms by which these chemicals may affect carcinogenesis and other adverse health outcomes.

Associations between polyfluoroalkyl substance and organophosphate flame retardant exposures and telomere length in a cohort of women firefighters and office workers in San Francisco

BACKGROUND

Environmental chemical exposures can affect telomere length, which in turn has been associated with adverse health outcomes including cancer. Firefighters are occupationally exposed to many hazardous chemicals and have higher rates of certain cancers. As a potential marker of effect, we assessed associations between chemical exposures and telomere length in women firefighters and office workers from San Francisco, CA.

METHODS

We measured serum levels of polyfluoroalkyl substances (PFAS), urinary metabolites of flame retardants, including organophosphate flame retardants (OPFRs), and telomere length in peripheral blood leukocytes in women firefighters and office workers who participated in the 2014-15 Women Workers Biomonitoring Collaborative. Multiple linear regression models were used to assess associations between chemical exposures and telomere length.

RESULTS

Regression results revealed significant positive associations between perfluorooctanoic acid (PFOA) and telomere length and perfluorooctanesulfonic acid (PFOS) and telomere length among the whole cohort. Models stratified by occupation showed stronger and more significant associations among firefighters as compared to office workers. Among firefighters in models adjusted for age, we found positive associations between telomere length and log-transformed PFOA ( β (95%CI) = 0.57(0.12, 1.02)), PFOS (0.44 (0.05, 0.83)), and perfluorodecanoic acid (PFDA) (0.43 (0.02, 0.84)). Modeling PFAS as categories of exposure showed significant associations between perfluorononanoic acid (PFNA) and telomere length among firefighters. Significant associations between OPFR metabolites and telomere length were seen for bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and telomere length among office workers (0.21(0.03, 0.40)) and bis(2-chloroethyl) phosphate (BCEP) and telomere length among firefighters (-0.14(-0.28, -0.01)). For OPFRs, the difference in the direction of effect by occupational group may be due to the disparate detection frequencies and levels of exposure between the two groups and/or potential unmeasured confounding.

CONCLUSION

Our findings suggest positive associations between PFAS and telomere length in women workers, with larger effects seen among firefighters as compared to office workers. The OPFR metabolites BDCPP and BCEP are also associated with telomere length in firefighters and office workers. Associations between chemical exposures and telomere length reported here and by others suggest mechanisms by which these chemicals may affect carcinogenesis and other adverse health outcomes.

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.

Management of Firefighters' Chemical & Cardiovascular Exposure Risks on the Fireground

The fire service research community around the world has focused substantial resources on reducing firefighter risk for sudden cardiac events and chemical exposures that may lead to cancer. Research presented here summarizes important lessons learned from a full-scale residential Fire Study that allowed quantification of the risks as well as the effectiveness of interventions to reduce those risks. To address fireground exposure concerns, personal protective equipment (PPE) and administrative controls exist. But, these controls are not always straightforward to apply. Leadership and management concerns with ongoing implementation of these controls are introduced and opportunities for change management are discussed. While research provides a solid basis upon which to institute policy and practice, fireground leadership and management is critical to ensure appropriate implementation.