Carbon monoxide (CO) exposure levels encountered by wildland firefighters (WLFs) throughout their work shift can change considerably within a few minutes due to the varied tasks that are performed and the changing environmental and fire conditions encountered throughout the day. In a U.S. Forest Service study during the 2009–2012 fire seasons, WLFs from 57 different fires across the U.S. were monitored for CO using CO data-logging detectors while an observer recorded worker tasks, fire characteristics, and environmental conditions at scheduled intervals. Exposures to CO for 735 WLF’s work shifts were analyzed to assess the effect of variations among work tasks, fire characteristics, and environmental conditions. Geometric mean full shift time-weighted averages were low at 2.4 parts per million (ppm) and average length of work shift was 11 hr and 15 min. The task with the highest mean CO exposure was sawyer/swamper at 6.8 ppm; workers performing that task had an estimated 9 times higher odds of a having a 1-min CO measurement exceeding 25 ppm than the referent pump task (OR = 8.89, 95% CI = 1.97, 40.24). After adjusting CO exposure limits for shift length, elevation, and work level, 2% and 4% of the WLF’s work shifts exceeded the National Institute for Occupational Safety and Health’s recommended exposure level and the American Conference of Governmental Industrial Hygienist’s threshold limit value, respectively. In regression modeling, variables that were significantly associated with elevated levels of CO exposure included: task, fuel model, wind orientation, crew type, relative humidity, type of attack, and wind speed. In the absence of instruments such as CO detectors that can determine and alert WLFs to elevated CO levels, recognition of the conditions that lead to elevated levels of CO exposure can assist WLFs to effectively use administrative controls, such as work rotations, to minimize exposures.

由于执行的任务多种多样，并且一天中遇到的环境和火灾条件不断变化，因此，野外消防员（WLF）在整个工作班次中遇到的一氧化碳（CO）暴露水平在几分钟之内可能会发生相当大的变化。在2009年至2012年火灾季节的美国林业局研究中，使用CO数据记录探测器对全美国57种不同火灾的WLF进行了CO监测，而观察员则按计划的间隔记录了工人的任务，火灾特征和环境条件。分析了735名WLF工作班次的CO暴露量，以评估工作任务，火灾特征和环境条件之间变化的影响。几何平均全班时间加权平均值低至2。百万分之4（ppm），平均轮班时间为11小时15分钟。平均CO暴露量最高的任务是锯木工/废料为6.8 ppm。进行该任务的工人估计1分钟的CO测量值超过25 ppm的几率比参考泵任务高9倍（OR = 8.89，95％CI = 1.97，40.24）。在调整了轮班长度，高度和工作水平的一氧化碳暴露限值后，WLF的工作班次分别超过了美国国家职业安全与健康研究院的建议暴露水平和美国政府工业卫生学家会议的阈值限值。在回归建模中，与升高的CO暴露水平显着相关的变量包括：任务，燃料模型，风向，机组人员类型，相对湿度，攻击类型，和风速。在没有诸如CO检测器之类的仪器可以确定WLF并向WLF发出警报的情况下，对导致CO暴露水平升高的条件的认识可以帮助WLF有效地使用管理控制，例如工作轮换，以最大程度地减少暴露。