Originally Posted By: trooper0366
My understanding of the ping pong balls is that they put in two chemicals that when mixed start to burn. They drop these where they want to remove fuel in front of the main fire. This strengthens the dug fire lines and denies the main fire of anything to burn so they can gain control. Its fighting fire with fire.


Correct, "ping pong balls" are just one of many potential sources of ignition for a backfire (or, for fuel management, prescribed burns). The chemical reaction is just potassium permanganate and antifreeze - it's not really a ping pong ball, it's a thick plastic sphere that contains a CC or two of KNO3. They're mechanically injected with antifreeze (or injected manually by bored hotshots just sitting around the station, who then toss the hot potato around) and it produces enough heat to ignite the plastic sphere.

Google "plastic sphere dispenser."
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(posting this as someone that has unintentionally done a bunch of stupid stuff in the past and will again...)