FX designer Rob Bottin (qv) used highly  flammable materials for the construction of interior of the head and  neck models. During the shoot John Carpenter (I) (qv) decided  that, for continuity reasons, they needed some flames around the  scene. Without thinking they lit a fire bar and the whole room,  which by now was filled with flammable gases, caught fire. Nobody  got hurt, but the entire special effects model, on which Bottin had  worked several months, was destroyed.