A few days after the flame had been lit, a drenching rainstorm extinguished the sacred flame. Only very briefly, however. An official with a cigarette lighter was nearby, and the flame sprang forth once more. Sacrilege! Fortunately the organisers had kept a reserve flame, originating at Olympia, burning in case of accident, and the "impure" fire was soon extinguished and replaced by a genuine Olympic flame.
http://www.olympic.org/uk/passion/museum/permanent/summer/montreal_uk.asp