A composition for generating smoke, consisting essentially of at least one chlorinated or chlorine-containing compound having a chlorine content of at least 56% by weight of said at least one compound, and a mixture of at least one metal oxide and at least one metal, the metal oxide being an alkaline-earth metal oxide and the metal being an alkaline-earth metal, and wherein the molar fraction of alkaline-earth metal, based on the total number of moles of alkaline-earth metal and alkaline-earth metal oxide, is between 0.33 and 0.67, the alkaline-earth metal contains particles having an average size of 50-100 μm and particles having an average size of 150-300 μm.