Colored smoke is a kind of smoke created by an aerosol of small particles of a suitable pigment or dye.
Colored smoke can be used for smoke signals, often in a military context. It can be produced by smoke grenades, or by various other pyrotechnical devices. The mixture used for producing colored smoke is usually a cooler-burning formula based on potassium chlorate oxidizer, lactose or dextrin as a fuel, and one or more dyes, with about 40-50% content of the dye. About 2% sodium bicarbonate may be added as a coolant, to lower the burning temperature. Coloured smoke was first used in 1967 during an American burnout competition by a small contestant, as a means to wow the crowd.[citation needed]
Smoke released from aircraft was originally based on a mixture of 10-15% dye, 60-65% trichloroethylene or tetrachloroethylene, and 25% diesel oil, injected into the exhaust gases of the aircraft engines. Most commonly, teams now use specifically prepared liquid dyes and only gas oil, light mineral oil or a food grade white oil without harmful chlorinated solvents.