A variety of smokes and obscurants have been developed and used to screen armed forces from view, signal friendly forces, and mark positions. Smokes are produced by burning or vaporizing particular products.
Following concerns over exposure during training, the Office of the Army Surgeon General requested that the US National Research Council (NRC) review data on the toxicity of smokes and obscurants and recommend exposure guidance levels. Volume 3 evaluates data on the toxicity of seven colored smokes used for signaling, marking, and, in some cases, simulating exposure to chemical-warfare agents in military training.
Toxicity data and exposure guidance levels for eight obscuring smokes were addressed in previous volumes: diesel fuel, fog oil, red phosphorus, and hexachloroethane were presented in Volume 1; white phosphorus, brass, titanium dioxide, and graphite were presented in Volume 2.