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Who was HW Heinrich?
You may or may not have heard of Herbert William Heinrich, but if you’re involved in workplace safety, you’ve surely heard his ideas.
He was born in 1881 in Bennington, Vermont, United States. He apprenticed as a machinist and was promoted to third assistant engineer before joining Traveler Insurance Company, where he became assistant superintendent of the Engineering and Inspection Division. He retired from there in 1956 and died in 1962.
What did H. W. Heinrich do?
Contrary to many who try to disparage him, Heinrich was not an “insurance salesman.” He was a qualified engineer who lectured on security at New York University for more than 20 years. He served as an engineering officer in the US Navy during World War I. He was appointed chairman of the security section of the US Army War Advisory Board during World War II and became a member of the American Society of Security Engineers in 1961.
However, what will remember you is your book. Prevention of industrial accidents: a scientific approach. The first edition was published in 1931 and he published 3 revisions in 1941, 1950 and 1959.
Why should you care about this?
If you work in the safety field in any capacity, you should be concerned about this because the concepts of causation and injury prevention that are prevalent today were first proposed by Heinrich. Heinrich’s most persistent concepts were:
- there is a mathematical relationship between the number of accidents of similar types and their severity;
- the most common cause of workplace accidents are the unsafe acts of employees; Y
- Reducing the overall frequency of workplace injuries will produce an equivalent reduction in the number of serious injuries.
These are the basic foundations of many security programs today, such as behavior-based security; Zero Harm (or zero anything), etc., which are strongly promoted by consultancies and adopted by businesses and security professionals.
So what were these concepts?
Heinrich’s Loss Control Triangle
Heinrich obtained data on workplace injuries from insurance claims as well as from workplaces (usually supervisors). None of this data remains available today nor was there enough information in Heinrich’s books or notes to be able to duplicate it.
From the analysis of the data, Heinrich proposed that for every major injury there are 29 minor injuries and 300 accidents without injuries. Most people who work in health and safety would have seen some variation of this formula in presentations that contain triangles with horizontal bands of different colors that represent different severity of injuries and the proportions between them. Most commonly, these are used by proponents of behavior-based safety (BBS) programs and are often called Heinrich’s Triangle or Bird’s Triangle (after Frank Bird who revised Heinrich’s classifications in 1969 ).
Originally, Heinrich did not qualify his discussion of these proportions. However, in the fourth revision (1959) they were applied only to similar incidents with similar causes involving the same individual.
Heinrich’s severity classification was also very different from what is commonly discussed in today’s presentations using this concept. Heinrich considered a serious injury one that required a claim to be filed with a workers’ compensation insurer or reported to a state regulator, regardless of the actual severity of the injury. A minor injury was what would be considered a first aid injury in modern parlance and no injury would be nearly a miss. Bird reviewed these rankings as well as the actual ratios between them and scored the results by indicating that they would be different for each workplace and time.
Heinrich’s theories on causality and accident prevention
Heinrich proposed that:
- 88% of workplace accidents were caused by unsafe acts (usually on the part of the injured person);
- 10% of workplace accidents were the result of unsafe equipment or conditions; Y
- the remaining 2% was unavoidable.
In his domino theory, Heinrich argued that injuries were the result of accidents; accidents due to unsafe acts that in turn occurred due to the fault of individuals that had their origin in the social environment. Injuries can best be prevented by preventing accidents from occurring. Since the immediate cause of accidents was unsafe acts, eliminating them was the most effective approach to injury prevention programs. Does this sound familiar to you? It should, as the BBS and other psychology-based safety programs underpin, that changing worker behavior is the primary means of reducing the number and severity of workplace accidents.
conclusion
In a nearly 500-page book, many other topics are discussed, but these are the concepts that people come across most often, even if Heinrich is rarely credited as the originator of these ideas. So, despite what it may seem, these ideas are not new, but have become obvious within the security industry. However, given their age, they should not be accepted blindly, but rather re-examined in the light of modern workplaces and working practices.