• Domino theory is a theory of the causes and management of accidents developed by H.W. Heinrich, who claims that all accidents, whether at home or in the workplace, are the result of a chain of events. The chain of events consists of the following successive factors: origin and social environment, human error, unsafe act and/or physical hazard, actual accident and injury resulting from antecedent factors. These factors are described as dominoes, and removing any of these five factors can prevent a crash.