Actually, nitrate is a little short of the mark. Modern smokeless propellent is based on nitroglycerin and/or nitrocellulose predominantly. While it's true that the molecular constuction of both contain nitrate submolecules, the chain sequence of nitroglycerin, or tris-nitroxy-propane, bind up the nitrates in a much more unstable and irregular fashion than conventional nitrate molecule chains like that found in fertilizer, which require a solvent to liberate the nitrate molecules into an unstable configuration. That is why you don't mess with unbuffered nitroglycerin, and why they add buffers, stabilizers, etc to make smokeless propellent really safe to handle. When UV and heat decompose the additives, you have problems.

Nitroglycerin is the explosive component of dynamite, which is a common explosive agent that the dogs are trained to scent. That's why the dogs key on powder residue.