Runaway reactions are a major source of industrial accidents. They can occur in a wide array of sectors, including chemicals, petrochemicals, food processing, plastics and rubber manufacturing, and metalworking and are primarily caused by a loss of process control. The processes involved are quite diverse, encompassing chemical reaction, polymerisation and distillation, among others. The loss of process control is related with various factors that are examined in this article. Several accidents that occurred in France and recorded in the ARIA1 database are used as examples.