Answer
The Domino theory describes an accident as a series of related occurrences that leads to a final event. In this theory, the causes are:
Lack of control
Basic causes
Immediate causes
Incident
Accident
The dominoes are stacked in a row, the first domino falling sets off a chain reaction of related events that result in an injury or accident. The start of a chain reaction is triggered when the controls breakdown.
Lack of control could be due to
An inadequate program
Inadequate standard of an existing program
Inadequate compliance to the standard at the implementation stage.
This Lack of Control leads to an emergence of a Basic Cause. Basic cause is referred to as the root, real or underlying cause which is not directly apparent but which latently promotes improper behavior and practices. Basic cause can be classified into:
Personal Factors (related to the person)
Job Factors (related to the work practices & procedures).
These latent causes need an active factor or a direct and immediate cause to set the domino in motion causing an Incident. These immediate causes can be seen or sensed. They are called:
Unsafe acts (behavior which could permit the occurrence of an accident)
Unsafe conditions (circumstances which could permit the occurrence of an accident)
Now the only thing that stands between an immediate cause and an accident is the event or the Incident. It is like striking the match in a tank filled with hydrocarbon vapor.
In this model, the source of an accident is the ‘lack of control’, meaning that safety starts at the top. By removing this domino from the chain, you can prevent the sequence of events from developing and thus prevent an accident.