I am sure everyone has had the occasional lump charcoal that seemed extra sparky? I assumed it was because I was using a lower price brand, Best of the West, at the time, but today (and yesterday) I noticed it with Wicked Good Weekend Warrior. I have observed one thing about most of the times this has happened - the specific piece of lump was shiny instead of dull.
Yesterday, I was cooking a few chicken breasts, I waited until the exhaust was clear smoke, and put the chicken on. After I had the chicken on for a bit, I started to notice a lot of sparkage, and the smoke went white again. When I went to check the temperature on the chicken I noticed a layer of soot was now on the chicken. I thought maybe it was my platesetter being particularly dirty; I cleaned the platesetter at 600 for about 30 minutes.
Today I was cooking a tri tip and the fire was still especially sparking, and popping, I figured it would burn out a bit. I then removed the piece of shiny lump that I noticed yesterday, the sparking stopped instantly. I am writing this to let people know if you see an shiny piece of lump and then once you start the fire it is popping and cracking - consider removing the shiny piece of lump.