Wildland firefighters in the US are mandated to identify areas that provide adequate separation between themselves and the flames (i.e. safety zones) to reduce the risk of burn injury. This study presents empirical models that estimate the distance from flames that would result in a low probability (1 or 5%) of either fatal or non-fatal injuries. The significant variables for the fatal injury model were fire shelter use, slope steepness and flame height. The separation distances needed to ensure no more than a 1 or 5% probability of fatal injury, without the use of a fire shelter, for slopes less than 25% were 20 to 50 m for flame heights less than 10 m, and 1 to 4 times the flame height for flames taller than 10 m. The non-fatal injury model significant variables were fire shelter use, vehicle use and fuel type. At the 1 and 5% probability thresholds for a non-fatal injury, without the use of a fire shelter, the separation distances were 1 to 2, 6 to 7, and 12 to 16 times greater than the current safety zone guideline (i.e. 4 times the flame height) for timber, brush and grass fuel types respectively.