Yes fire can destroy the chemicals, however I saw a description of the proper way to incinerate the poly stuff and the open pit fire was not the right way to do it. There were specific temperatures that needed to be achieved to ensure all of it was rendered inert. Open pit fires do not achieve those temperatures. The black smoke from the fire demonstrated that combustion was incomplete. So some stuff was destroyed in the fire, some stuff was converted into other toxic compounds in the fire and released as smoke, other parts of it were just evaporated and sent billowing into the air.