How a small thing becomes a serious one

Serious incidents almost never come from nowhere. They are the last step in a chain, and most of the earlier steps were in plain sight, if anyone had been looking.

The clearest way to picture this comes from the psychologist James Reason, who spent his career studying how good people and good systems still fail. His idea is usually called the Swiss cheese model, and once you have seen it you cannot unsee it.

The holes that line up

Imagine every defence you have against harm as a slice of Swiss cheese. Training is a slice. A machine guard is a slice. Supervision, inspections, a second pair of eyes: more slices. Each one stops most things. Each one also has holes, the gaps where that defence does not quite work, and the holes move around from day to day.

Most of the time the holes do not line up, so a risky moment passes and nothing happens. Every so often they do line up, and the hazard sails straight through every layer at once. That is an accident. It is rarely one big failure. It is usually several small ones that happened to agree.

This explains a feeling every safety lead knows. A near miss looks like “no harm done”. In truth it is “the holes did not line up this time”. It is the same event as the accident, minus luck. Which makes it the cheapest data you will ever be handed.

Trace it back and every link is ordinary

Picture a trailing cable nobody tidied, a shift running late, a poorly lit corner, and a worker carrying a load they cannot see past. Any one of those on its own is survivable. Stack them and you have a fall. Investigate afterwards and you find that not one link in the chain was dramatic. They were all the small, ordinary conditions that had been there for weeks.

A near miss is not a lucky escape to be relieved about. It is a free rehearsal for the real thing, with the answers already written down.

The scale of what is at stake is sobering. The World Health Organization and the International Labour Organization estimate that 1.9 million people died from work-related causes in 2016, with long-term diseases accounting for about 81 per cent and injuries the rest. Very few of those were freak events. Most were slow chains that nobody followed to the end in time.

What actually helps

Three habits, none of them expensive. Write down the small stuff, the slip that hurt no one and the guard that was missing for an hour. Look for the conditions rather than the culprit, because blaming a person leaves every hole exactly where it was. And after any near miss, ask one more question: what else would have had to go wrong for this to be serious? The answer is your map of the holes.

It is unglamorous work. Someone writes down a thing that did not hurt anyone, on a phone, at the end of a long shift. That note is a slice of cheese with one fewer hole in it. Enough of them, and the holes stop lining up.

References

1. James Reason, “Human error: models and management”, BMJ, 2000;320:768. bmj.com.
2. James Reason, Human Error (Cambridge University Press, 1990).
3. WHO and ILO, “Almost 2 million people die from work-related causes each year”, 17 September 2021. who.int and ilo.org.

Written and published by Logincident.