The fire was caused Causation by pyrotechnics set off Placing by the tour manager of the evening 's headlining band , Great White , which ignited Causation flammable acoustic foam in the walls and ceilings surrounding Surrounding the stage .

Investigators subsequently found Know evidence of suitcases with explosives and flammable material , including three undetonated bombs .

The tanker truck was loaded with 23 tons of highly flammable liquefied Change propylene .

The investigation Criminal_investigation carried out Military_operation by the Transportation Safety Board of Canada ( TSB ) concluded that flammable material used in the aircraft 's structure allowed Preventing_or_letting a fire to spread Dispersal beyond the control of the crew , resulting in Causation the crash Catastrophe of the aircraft .

The report 's conclusion was that the probable cause Causation of the accident was explosion Attack of flammable fuel vapors in the center fuel tank .