"...shoot it with a tracer..." Doesn't do anything. LP needs an evil incendiary to light it. The Night Tracer Festival at Second Chance long ago was some you had to see to believe. Several 100 and 25 pound LP tanks, gasoline, fireworks, a refridgerator, a car. Trace and regular ball had absolutely no effect other than creating a nice gentle white cloud. The .50 BMG APTI was required to light said cloud.
Trace doesn't start fires unless the grass is very dry and you're unlucky. The lights you see flying around on a range or in movies(real footage not Hollywood) for trace hitting a target is the trace element, not the bullet.
"...never seen chem fall out..." It doesn't always, but it can with rough handling.