Domino Theory

Heinrich’s traditional 5 Domino Theory on accident causation is the standard model used by health and safety professionals. The theory works on the basis that, if a domino falls, it will be a matter of time before it will knock down the others next to it. This, he says is the way with workplace health and safety, where one undesirable event in the workplace will lead to others, and eventually to an accident.

Heinrich’s Dominos – The Process

1. A personal injury (the final domino) occurs only as a result of an accident.

2. An accident occurs only as a result of a personal or mechanical hazard.

3. Personal and mechanical hazards exist only through the fault of careless persons or poorly designed or improperly maintained equipment.

4. Faults of persons are inherited or acquired as a result of their social environment or acquired by ancestry.

5. The environment is where and how a person was raised and educated.

The factor preceding the accident (the unsafe act or the mechanical or physical hazard) and it should receive the most attention. Heinrich felt that the person responsible at a company for loss control should be interested in all five factors, but be concerned primarily with accidents and the proximate causes of those accidents.

Heinrich also emphasized that accidents, not injuries or property damage, should be the point of attack.

– An accident is any unplanned, uncontrolled event that could result in personal injury or property damage. For example, if a person slips and falls, an injury may or may not result, but an accident has taken place.