Actually, out of the 3 options that they had, burning it was the best one..
I saw one plume maybe two that may of been a discharge from a pressure relief valve operating as designed or a sheered off valve, which is distinct possibility.
There was nothing controlled.
At that point in the disaster timeline, it was suicide for any first responder to get within 100 yards of the fire. Initially, the responders when the fire had burned out a lot, would have been focused first on containment insofar as possible and cooling the fire via hoses from the responding fire engines.
By the way…. You still reading that rag Chemical Violence? Lol…