Heinrich Pyramid Discussion – Where are you?
I thought it was time to bring this topic up again.
Back in 2007, I wrote a short article and gave several talks at professional society conferences about the “accident pyramid” or the “Heinrich Pyramid.”
At the time, people were saying that the pyramid wasn’t accurate or useful for safety improvement.
I think that much of the misunderstanding and debate starts with a misuse of what the pyramid represents.
The original pyramid was based on Heinrich’s work in the insurance industry in the 1920’s and 1930’s (see above). The writing below the pyramid says that of 330 similar events, 1 will result in a major injury, 29 will result in a minor injury, and 300 will result in no injury at all.
Thus, because the events are similar, ALL 330 events could have caused a major injury, but 329 did not because of luck or some other circumstance.
As time went on, people modified Heinrich’s Pyramid. There was the Frank Bird modification (Loss Control Management: Practical Loss Control Leadership, 1969):
People interpreted this graph as meaning that for every major injury there would be 600 unsafe acts. Sometimes people didn’t say that the unsafe acts had to be capable of causing the major injury.
Also, there was the Krause, Hindley, and Hodson Pyramid (The Behavior-Based Safety Process, 1990):
This replaced many of the terms on the pyramid and introduces behavior as the ultimate cause of injuries and fatalities.
And finally, the nuclear safety iceberg:
Which once again, focussed on behaviors and latent conditions and didn’t mention the significance of the Safeguard that was being weakened.
From these new pyramids, people got the idea that focusing on unsafe acts and behaviors could stop major accidents. However, many lost the idea that the behaviors or unsafe acts had to be capable of causing a major accident/fatality or removing a Safeguard to a major accident or fatality. Thus, people started focusing on any small injury as a way of preventing big injuries or small problems to prevent reactor meltdowns.
However, stopping paper cuts won’t prevent major process safety related accidents or industrial safety fatalities.
None the less, some safety programs were mislead into thinking that stopping first aid cases would lead to an end to fatalities. Many programs were overwhelmed by small problems to investigate and they started using questionable root cause analysis tools to speed up the investigations.
Thus, even incidents which had the potential to cause a major accident/process safety disaster/fatality were investigated using questionable root cause analysis tools. The result was ineffective corrective actions that may have reduced minor incidents but didn’t stop major accidents.
Companies improved their first-aid cases (or at least less were reported) but continued to have fatalities and major accidents at about the same rate.
(I worked at a site where supervisors learned to carry a first-aid kit to treat injuries and stop people from going to the site nurse/doctor. The result? First-aid cases dropped dramatically. Was this a safety improvement?)
About a decade ago, some of the same people who revised the Heinrich Pyramid realized that correcting the causes of first-aid cases was not preventing fatalities. Thus began the research on significant injuries and fatalities (SIFs). The researchers came up with a new model:
This put the emphasis on industrial safety back on the activity (energy) that could kill you and the Safeguard that kept you safe.
This was a good start but insufficient. Why? Because some activities (process safety or driving) could always kill you.
In process safety, there are so many Safeguards that people begin to take the hazard (energy) for granted. Examples? Three Mile Island, Texas City Refinery explosion, Chernobyl, Deepwater Horizon.
In driving, there are very few safeguards to prevent the accident, but several incorporated into the design of the vehicle to try to prevent a fatality.
For process safety, you need to focus on maintaining the multiple, redundant Safeguards and investigate the failure of any Safeguard as an incident. Process safety requires an abnormal level of attention to detail.
In traffic safety, the focus on individual skills, adequate rest (fighting fatigue), and highway safety improvements seems to be the most logical approach.
Now to the title of this article.
Where are you?
- Are you still investigating incidents that aren’t worth investigating?
- Are you using ineffective root cause analysis tools to save time?
- Are you improving (or at least getting less reported) small incident but still having fatalities?
Perhaps it is time to learn about advanced root cause analysis and how it can be applied to small incidents that could cause major accidents (precursor incidents) and how this can be done in an efficient manner?
Or, attend one of our TapRooT® Courses to learn to use the TapRooT® System. Here is a list of the dates and locations of upcoming 5-Day TapRooT® Advanced Root Cause Analysis Team Leader Training Courses: