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The objective of this study was to document characteristics of hiking during wildland firefighter (WLFF) training and wildfire suppression. For the first time, the overall physical demands during wildland firefighting were evaluated in the field using global positioning systems coupled with wireless physiological monitoring and load carriage prediction models.Male (n=116) and female (n=15) interagency hotshot crew and type II WLFFs on wildfires volunteered for this direct observation study. Participants' heart rate, internal temperature, speed, and elevation gain were monitored throughout training and during wildfire suppression. The Pandolf and Santee equations were used to predict metabolic rate to estimate oxygen consumption of uphill and downhill hiking.Equipment weight varied by crew type (type II: 24±9 kg and interagency hotshot crew: 28±6 kg; P0.05). Grade of terrain was steepest during training hikes, and ingress hikes were statistically different from egress and training hikes (ingress: 4±9%, shift: 4±9%, egress: 1±8%, training hikes: 10±9%; P0.01). Estimated oxygen consumption was highest during ingress hikes and was significantly different from all other hike types on fire assignments (ingress: 22±12, shift: 19±12, egress: 19±12 mL·kgThe greatest metabolic demand during wildfire assignments occurred during ingress hikes. On average, this was close to the estimated metabolic demand of the job qualification arduous pack test. However, greater metabolic demand occurred for periods during both shift (on the job) and training hikes. These data quantify the demands associated with actual wildland performance of WLFFs and can help define future work capacity testing and training procedures.

On Sunday, 30 June 2013, on mountainous terrain near Yarnell Hill, Arizona, a team of fire fighters was racing to escape entrapment from an approaching wildfire. It was a race they would not win. In the days following the event, the shocking news came forth that 19 members of the elite Granite Mountain Interagency Hotshot Crew had perished.

Respiratory problems are common among wildland firefighters. However, there are few studies directly linking occupational exposures to respiratory effects in this population. Our objective was to characterize wildland fire fighting occupational exposures and assess their associations with cross-shift changes in lung function. We studied 17 members of the Alpine Interagency Hotshot Crew with environmental sampling and pulmonary function testing during a large wildfire. We characterized particles by examining size distribution and mass concentration, and conducting elemental and morphological analyses. We examined associations between cross-shift lung function change and various analytes, including levoglucosan, an indicator of wood smoke from burning biomass. The levoglucosan component of the wildfire aerosol showed a predominantly bimodal size distribution: a coarse particle mode with a mass median aerodynamic diameter about 12 μm and a fine particle mode with a mass median aerodynamic diameter < 0.5 μm. Levoglucosan was found mainly in the respirable fraction and its concentration was higher for fire line construction operations than for mop-up operations. Larger cross-shift declines in forced expiratory volume in one second were associated with exposure to higher concentrations of respirable levoglucosan (p < 0.05). Paired analyses of real-time personal air sampling measurements indicated that higher carbon monoxide (CO) concentrations were correlated with higher particulate concentrations when examined by mean values, but not by individual data points. However, low CO concentrations did not provide reliable assurance of concomitantly low particulate concentrations. We conclude that inhalation of fine smoke particles is associated with acute lung function decline in some wildland firefighters. Based on short-term findings, it appears important to address possible long-term respiratory health issues for wildland firefighters. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resources: a file containing additional information on historical studies of wildland fire exposures, a file containing the daily-exposure-severity questionnaire completed by wildland firefighter participants at the end of each day, and a file containing additional details of the investigation of correlations between carbon monoxide concentrations and other measured exposure factors in the current study.]