Propane furnace showing soot!?

I just went to fire up the furnace...it's getting chilly outside and in. Anyway, I always check things out, like filters etc before cranking things on. I noticed soot just above the Control Access Panel. When I tap on the ductwork above, some more falls out. I went ahead and turned it on and watched it for a while and little bits of firey red soot was falling....not a lot but still some. It's being caught by the top edge of the Access Panel where it hooks on, and is pretty much out before it lands. What could this be and is it cause for alarm?