Check out this smoke screen that was used during World War II. It was dispensed from aircraft to create vertical smoke curtains and was made of Titanium tetrachloride (FM).

Titanium tetrachloride (FM) is a colorless, non-flammable, corrosive liquid. In contact with damp air it hydrolyzes readily, resulting in a dense white smoke consisting of droplets of hydrochloric acid and particles of titanium oxychloride. [source]