The present study examined the ability of signal words (e.g. DANGER) and their associated panels to convey hazard-level information, both individually and redundantly. Subjects constructed signs on a computer for 30 different scenarios. The use of signal words and panels was observed as a function of the level of hazard associated with the scenario. The results show that (a) the connoted level of hazard for signal words is not perceived as most standards suggest, (b) certain panel components (e.g. colour and symbols) are most critical in conveying hazard-level information, (c) no current set of standards or recommendations specifies panel formats which use these panel components optimally, and (d) the use of signal word panels was not necessarily based on the choice of signal word or on the level of hazard for the particular scenario. The results suggest the need for a re-evaluation of current signal word hierarchies.