Chain Reaction began when Ward spun coming out of southeast turn (right) and began to roll. Keller and Boyd collided just short of footbridge (explosion star) when Keller swerved left to avoid Ward. Vukovich, leading Keller by two laps, was thus confronted by three crazily-gyrating cars as he roared up from turn. He tried to get through on outside and apparently passed Ward before latter's car, back on its wheels, backed into rail; but he could not avoid hitting the still-spinning Boyd. Boyd's car plunged down the track and landed upside down; Vukovich's climbed the rail, skittered along it, then somersaulted off and burned, trapping the driver beneath it. Elisian, not involved in the accident, spun deliberately to halt his car in the infield.