Understanding the Safety Pyramid

In the 1930s, a man named H. W. Heinrich had a theory about workplace safety. So, he reviewed 75,000 injury records from his insurance company’s archives, as well as documents by manufacturing sites. The result is a theory called Heinrich’s Law, or the safety pyramid. OSHA still uses the theory today. More recent research shows that it’s a valid (but complicated) theory.

Here’s what you need to know about the safety pyramid and how you can apply it to your incident management.

What is the Safety Pyramid?

The safety pyramid, sometimes called the safety triangle, is a pictorial representation of a concept called Heinrich’s Law, developed by H. W. Heinrich. Heinrich, an employee of the Traveler’s Insurance Company in the 1930s, published a series of groundbreaking theories on health and safety at work.

The most famous of these is Heinrich’s Law, which states, “in a workplace, for every accident that causes a major injury, there are 29 accidents that cause minor injuries and 300 accidents that cause no injuries.”

Heinrich’s Law indicates a relationship between major injuries, minor injuries, and near-misses. Heinrich’s most-cited figure states that 88% of all injuries and incidents are caused by a human decision to perform an unsafe act.

Heinrich concluded that by lowering the number of minor injuries, businesses could reduce the total number of major injuries and incidents. And while Heinrich’s most often cited figure would suggest an emphasis on man-made failures, Heinrich actually suggested that workplaces focus on hazards, not just worker behavior.

Critiques and Recent Studies

One of the common critiques of Heinrich’s Law is that it overemphasizes worker behavior on an individual level, rather than studying a complete workplace system.

However, more recent research has backed up Heinrich’s work. In 2018, NIOSH conducted a study to test whether Heinrich’s conclusions were sound. They found it to be a useful but complicated theory to predict workplace injuries.

The study originally aimed to examine if minor, less severe injuries affected the number of fatalities in mines over time, one of Heinrich’s key conclusions. They also sought to test whether the probability of fatalities decreases as the number of near-misses and minor incidents decreases. It drew from 13 years of data from 27,446 establishments.

Results showed that a lower-severity events in a mine may be used to predict fatalities within the same mine. They also found that the safety pyramid applies in mining, but it depends on the definition of injury severity. In other words, the safety pyramid exists, but not for all approaches to define injury severity. The pyramid was most applicable to severity metrics linking the number of lost work days to work-related injuries.

Safety Beyond the Safety Pyramid, OSHA, and Injuries

What can companies take away from the safety pyramid? OSHA’s theory is effective, but complicated, and it depends on how you define injury severity. The best takeaway is simple: the use of data to find common causes when investigating accidents.

That’s where we can help, with data-oriented safety management software that makes it easy to take charge of your data to draw practical conclusions. Ready to take a smarter approach to safety? Get in touch today to learn how our software can help.