Development of a wildland fire respirator. Two versions are being tested, with the filter being carried on the chest hip. Department of Homeland Security photo.
A working group for the International Agency for Research on Cancer, the cancer agency of the World Health Organization, has just “classified occupational exposure as a firefighter as carcinogenic to humans.” Part of the reason is the toxic gasses firefighters are exposed to.
Wildland firefighters working on a vegetation fire can’t wear the conventional self contained breathing apparatus used by structural firefighters. It is too bulky, heavy, and only lasts 10 to 30 minutes.
In an effort to provide less carcinogenic air to wildland firefighters, the Department of Homeland Security’s Science and Technology Directorate is developing a respirator capable of removing airborne hazards present in the wildland firefighting operating environment. They are working with the International Association of Firefighters, National Fire Protection Association, International Association of Fire Chiefs, U.S. Forest Service, and local Colorado fire departments to develop and test the Directorate’s Wildland Firefighter Respirator (WFR). It contains a HEPA filter module that will remove very fine particulates, and a carbon sorbent to remove toxic gases. The team is investigating wildland firefighter-approved designs like the Radio Carrier and Hip-Mounted units shown in the photo below.
Development of a wildland fire respirator. Two versions are being tested, with the filter being carried on the chest hip. Department of Homeland Security photo.
The WFR was designed around a lightweight mask covering just the mouth and nose. It relies on filtration, designed to go a whole shift before needing to be changed.
“Our system pushes clean air to firefighters using a powered blower with HEPA and carbon filters,” said S&T Program Manager Kimberli Jones-Holt. The system connects to the half-mask through a lightweight, flexible breathing hose to provide clean air and draws in air from the bottom of the unit to prevent rain or water infiltration.
“The filters were also designed to be inexpensive and easily replaced at $5 to $10 each,” Jones-Holt continued.
It uses an electric blower to force filtered air to the mask, relying on AA batteries for power.
The DHS says if wildland firefighters use respiratory protection, their careers could be significantly extended, leading to a more educated and experienced workforce capable of more efficient operations, with lower medical bills and training costs.
Inhaled microscopic particles from wood smoke can work their way into the bloodstream and reach the brain, putting people at risk for premature aging and various forms of dementia, depression, and even psychosis
Here is a very brief look at the effects of smoke on wildland firefighters, and below that, a longer look, in the embedded four-page .pdf document.
By Kathleen M. Navarro, U.S. Forest Service (currently with the Centers for Disease Control and Prevention)
Wildland firefighters are exposed to health hazards including inhaling hazardous pollutants from the combustion of live and dead vegetation (smoke), and breathing in ash and soil dust, while working long shifts with no respiratory protection. This research brief summarizes a study estimating long-term health impacts of smoke exposure for wildland firefighters (Navarro et al. 2019). The study estimated relative risk of lung cancer and cardiovascular disease mortality from existing particulate matter (PM) exposure-response relationships using a measured PM concentration from smoke and breathing rates from previous wildland firefighter studies across different exposure scenarios.
Key Findings:
Firefighters who worked both short and long seasons (49 days and 98 days per year, respectively) were exposed to increased lifetime doses of PM4 across all career durations (5-25 years).
Wildland firefighters were estimated to be at increased risk of lung cancer (8 to 43 percent) and cardiovascular disease (16 to 30 percent) mortality across all season lengths and career durations.
These findings suggest that wildland firefighters should reduce exposure to smoke in any way possible.
[pdf-embedder url=”https://wildfiretoday.com/wp-content/uploads/2021/06/NRFSN_ResearchBrief7_FirefighterSmokeExposure_HealthRisk_2020_final.pdf” title=”wildland Firefighter Smoke Exposure Health Risk2020″]
Using observations from crowdsourced science and weather location data, researchers concluded that wildfires caused a mass die-off of birds in the western and central United States in 2020.
Photo of smoke from bushfires by Merrin Macleod on a flight from Canberra to Melbourne, Australia, posted January 4, 2020.
Originally published by the Centers for Disease Control and Prevention
While research has not yet been conducted on all the hazards and risks associated with the wildland firefighting job, the National Institute for Occupational Safety and Health (NIOSH) is asked numerous questions about the hazards of fighting wildland fires. This blog is designed to answer some of those questions.
What Is in Wildland Fire Smoke?
Wildland fire smoke is a mixture of gases and particles such as carbon monoxide (CO) and respirable particulate matter (PM) that may cause short- and long-term health effects. Wildland firefighters can be exposed to smoke at wildfires and “prescribed” fires (planned and intentionally ignited low-intensity fires). The contents of and exposure to wildfire smoke can vary greatly throughout the day depending on the vegetation type, fire behavior, and meteorological conditions. Research has shown that wildland firefighters have been exposed to gases and particles such as CO and PM above the occupational exposure limits during both wildland and prescribed fires. While burning vegetation is the primary exposure of concern for wildland and prescribed fires, when fires burn in the wildland urban interface (WUI, where wildland vegetation and urban areas meet) the smoke may contain compounds that are more similar to what structural firefighters encounter. Wildland firefighters will often suppress these fires and may be exposed to some of the hazardous compounds of WUI smoke such as volatile organic compounds (VOCs), flame retardants, and polycyclic aromatic hydrocarbons (PAHs). However, wildland firefighters do not have the benefit of wearing some of the personal protective equipment (PPE) typically used in a structural response (e.g., self-contained breathing apparatus [SCBA], turnout gear) that could provide protection from these compounds. Additionally, wildland firefighters may be exposed to smoke at firefighting base camps (incident command posts) where they eat and rest while off-duty.
What Do We Know About the Health of Wildland Firefighters?
Cardiovascular and Lung Health
In the past decade, several studies have linked exposure to wildfire smoke to short-term health effects, such as increases in inflammation and respiratory effects, for example, lung function decline.[i] However, these studies have only examined the health effects across a few shifts or a single fire season. It is not clear if these adverse health effects continue after fire season and whether they worsen after several seasons of fighting fires. Researchers suspect that exposure to particulate matter and other contaminants from wildfire smoke, heavy physical exertion, existing health and behavior risk factors, and cardiovascular strain could contribute to sudden cardiac events for wildland firefighters. Recent research indicated that wildland firefighters may be at an increased risk of mortality from cardiovascular disease and lung cancer than the general public from career exposure to wildfire smoke.[ii]
COVID-19
The strenuous work, long work shifts, close living and working conditions, limited access to hygiene supplies, and a workforce that responds to incidents all over the country on short notice to wildland fire incidents may be conducive for the transmission of infectious diseases, including SARS-CoV-2. Exposure to air pollutants in wildfire smoke can irritate the lungs, cause inflammation, alter immune function, and increase susceptibility to respiratory infections, possibly including COVID-19.[iii] In addition to potentially making firefighters more vulnerable to getting COVID-19, inflammation in the respiratory tract due to wildfire smoke might also increase the risk of developing more severe outcomes for those with COVID-19.[iv] Wildland firefighters should implement the recommendations described in the CDC’s FAQ for Wildland Firefighters to prevent infection and spread of COVID-19.
Heat-Related Illness and Rhabdomyolysis
Due to the nature of their work, firefighters are at risk of developing severe heat-related illness (such as heat stroke) and rhabdomyolysis (muscle breakdown).[v],[vi] Delays in diagnosis and initiating treatment of these illnesses increase the risk of permanent muscle damage. Since 2010, 62 cases of severe rhabdomyolysis among wildland firefighters have been reported to a passive surveillance system designed to capture fatalities and certain types of injuries and illnesses including rhabdomyolysis. The actual number of cases is likely higher due to underreporting and inconsistencies in reporting requirements and systems. Prior to 2010, no cases were reported.
Hearing
Wildland firefighters work around power tools and heavy equipment that produce noise levels that are hazardous to hearing. In addition to hearing loss, noise exposure may also cause tinnitus (ringing/buzzing in ears), increased heart rate, fatigue, and interfere with verbal communication. Researchers from NIOSH and the United States Forest Service (USFS) evaluated personal noise measurements on 156 wildland firefighters conducting various training and fire suppression tasks, and reported that 85 of the 174 measurements were above the NIOSH maximum allowable daily dose[vii]. A follow-up study showed use of hearing protection was mixed; while almost all the wildland firefighters were aware of the noise in their environment and potential risk, very few were enrolled in hearing conservation programs.
What Are NIOSH Researchers Doing to Better Understand Exposures and Health Effects?
NIOSH is currently conducting research to understand the exposures and health effects of firefighters suppressing wildland and WUI fires. NIOSH researchers and collaborators at the US Forest Service and Department of the Interior have finished the second year of a multi-year study investigating exposures and health effects among six federal 20-person firefighting crews. The primary goal of this study is to measure exposures in the wildland fire environment and examine associations between those exposures and changes in lung, cardiac, kidney, and hearing function during each fire season and the off season over multiple fire seasons. This study has been paused in 2020 due to COVID-19 but is expected to resume.
To understand exposures and health effects faced by WUI firefighters, NIOSH is working with researchers from the University of Arizona and University of Miami to expand an existing collaborative research study (the Fire Fighter Cancer Cohort Study) to collect data regarding exposures from WUI fire incidents during the 2019 and 2020 fire seasons. Characterizing the types of chemicals, as well as the routes and levels of exposures, will help us understand health risks for wildland firefighters.
NIOSH is also in the process of developing a study assessing self-reported exposures to wildfire smoke and COVID-19 health outcomes among wildland firefighters. Additional information about this research will be available soon on the NIOSH Fighting Wildfires Page.
Authors of this article:
LCDR Corey Butler,MS REHS, is a Lieutenant Commander with the United States Public Health Service and an Occupational Safety and Health Specialist in the NIOSH Western States Division.
CAPT Christa Hale,DVM, MPH, DACVPM (Epi), is a Captain with the United States Public Health Service and Senior Epidemiologist and Veterinarian in the NIOSH Western States Division.
Kathleen Navarro, PhD, MPH is an Associate Service Fellow with the Division of Field Studies and Engineering.
Elizabeth Dalsey, M.A., is a Health Communication Specialist in the Western States Division.
CAPT Chucri (Chuck) A. Kardous, MS, PE, is a Captain with the United States Public Health Service and a research engineer with the NIOSH Division of Field Studies and Engineering.
Pamela S. Graydon, MS, COHC, is an Electronics Engineer working in hearing loss prevention in the NIOSH Division of Field Studies and Engineering.
CAPT David C. Byrne, Ph.D., CCC-A,is a Captain with the United States Public Health Service and a research audiologist with the NIOSH Division of Field Studies and Engineering.
References
[i] Adetona O, Reinhard T, Domitrovich J, Boryles G, Adetona A, Kleinman M, Ottma R, Naher L [2016]. Review of the health effects of wildland fire smoke on wildland firefighters and the public. lnhal Toxicol 28(3): 95-139. Available from: https://pubmed.ncbi.nlm.nih.gov/26915822/
[ii] Navarro K, Kleinman M, Mackay C, Reinhardt T, Balmes J, Broyles G, Ottmar R, Naher L, Domitrovich J [2019]. Wildland firefighter smoke exposure and risk of lung cancer and cardiovascular disease mortality. Environ Res 173:462-468. Available from:https://www.sciencedirect.com/science/article/pii/S001393511930194X
[v] West MR, Costello S, Sol JA, Domitrovich JW [2020]. Risk for heat-related illness among wildland firefighters: job tasks and core body temperature change. Occup Environ Med77(7):433-438. Available from: https://pubmed.ncbi.nlm.nih.gov/31996475/
[vi] NIOSH [2012]. Report of a NIOSH health hazard evaluation, HHE 2011–0035. By Eisenberg J and McFadden J. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. Unpublished.
Photographers at a wildland fire may be able to use and tolerate a mask that traps 95 percent of the 0.3 micron particulates in smoke, but the devices are not practical for firefighters. (see photo above)
In case you are wondering, masks and respirators are divided into rating classes: N is not oil resistant, R is oil resistant, and P is oil proof. The number, such as 95, refers to the percent of particles removed that are at least 0.3 microns in diameter.
