Sodium nitrate
From PyroGuide
Formula: NaNO3
Description: Sodium nitrate finds occasional use as an oxidiser in flare and tracer compositions because of the high efficiency of light emmision that can be obtained with it, but its high hygroscopic nature limits its use. Sodium nitrate can be used to prepare potassium nitrate, a much less hygroscopic and more often used oxidiser.
Hazards: Sodium nitrate is not healthy to eat, but careful use as always with chemicals make it not dangerous to work with. Since it's very hygroscopic it can cause dangerous mixes with Aluminium or Magnesium.
Sources: sodium nitrate is sold as a food preservative, 95% pure sodium nitrate is also available as a fertilizer. In the Netherlands this fertilizer is sold under the name 'chilisalpeter'. If required, it can be easily purified by recrystallisation.