Due to the promotion of renewable energy sources, the demand for ethanol/automotive fuels has increased, whereby the ethanol is produced from biomass. As these fuels are flammable liquids, explosion protection concepts are needed for their transport, use and storage and for the operation of petrol stations. Safety characteristics are the basis of such concepts. Since the data for ethanol, on the one hand, and for automotive petrol, on the other hand, differ considerably, the relevant data for the ethanol/automotive petrol mixtures have to be determined and the existing explosion protection concepts will possibly have to be limited or modified. For this reason the correlations between the necessary safety characteristics – flashpoint, boiling point, auto-ignition temperature, maximum experimental safe gap, upper explosion point – and the mixing ratio of ethanol and automotive fuel have been investigated. Based on the results of this investigations, those concentration limits are elaborated for which the existing safety concepts remain valid. For mixtures with an ethanol content going beyond such limits, suitable safety measures and requirements regarding explosion-protected equipment are derived. The changes that are necessary with respect to the safety concept of petrol stations when ethanol/automotive petrol mixtures are offered instead of or in addition to pure petrol are explained.