Every year, Australian firefighters protect our nation from the devastation of bushfire. Understanding the impact of consecutive long shifts in hot, smoky conditions is essential for making decisions during campaign fires. At present, the evidence-base for such decisions is limited to laboratory studies with little relevance to bushfire suppression or field research where the impact of environmental and workload stressors cannot be measured. To counter these limitations, we have developed a three-day simulation that mimics the work and environment of campaign bushfire suppression. Construction of the simulation involved three stages; 1) data collection and analysis; 2) design and development; and 3) trial and refinement. The frequency, intensity, duration and type of physical work performed on the fireground is well documented and a modified applied cognitive task analysis, using experienced firefighters was used as a framework to describe in detail the non-physical aspects of the work. The design and development of the simulation incorporated the physical and non-physical aspects of the work into simulated tasks. Finally, experienced firefighters participated in trials of the simulation and reviewed digital recordings to ensure that the simulation accurately represented campaign bushfire suppression work. The outcome of this project is a valid, realistic, and reliable simulation of the physiological, physical and cognitive aspects of a volunteer firefighter on a three-day bushfire deployment.<br /