The Missouri Pacific Railroad's freight train 94 was traveling north on track which belongs to the Atchison, Topeka and Santa Fe Railway when 20 of its cars derailed in Houston, Texas, on October 19, 1971, at 1:44 p.m. There were four diesel electric locomotive units and 82 cars in the train. Derailed cars included six tank cars containing vinyl chloride monomer and two cars containing other hazardous materials. Two tank cars were punctured in the derailment. The vinyl chloride monomer escaped and ignited. The Houston Fire Department attempted to control the fire. Approximately 45 minutes after the initial derailment, one tank car ruptured violently and another tank car "rocketed" approximately 300 feet from its initial resting place. This sequence of events caused the death of a fireman. Fifty people were injured and there was considerable property damage. Most of the injured were firemen.