Why Workplace Accidents Happen

The term accident implies that it is an unexpected, undesired, and an unplanned event. However, the word “unexpected” leaves this definition open for interpretation. What is truly unexpected? For example, if someone is driving at excessive speeds is it not well understood that this type of activity has a high probability of resulting in an accident? If a construction worker doesn't wear eye protection while hammering, is it not well understood that this type of activity has a high probability of resulting in an accident — debris flying into the eye? So the real question is what is truly unexpected? If it is foreseeable than perhaps it is not unexpected.

It is a well known fact that most accidents, about 90%, are caused by human error. It may not be directly by the person using the tool, but somewhere along the line, e.g. manufacturer or the electrician that installed the fuses, you will find an error made by a human. Even though it may not have been on purpose, it is nevertheless a human error.

There are two types of human failures: 1) errors and 2) violations.

Errors i.e. done on purpose, there are two types.

1. Skill based errors:
• Slips of actions: total fluke missed a step.
• Lapses of memory: forgot to perform a step.
2. Mistakes:
• Rule based mistakes: wasn't aware of the rules.
• Knowledge based mistakes: lacked some knowledge on the task.

Violations i.e. done on purpose, there are three types:

1. Routine: someone that routinely violates rules e.g. speed on all roads.
2. Situational: someone that violates rules but only in specific situations e.g. speeds only on the highway.
3. Exceptional: someone that follows the rules and it is rare for breaking them.

In attempting to reduce accidents in the work place, all areas must be addressed. Errors, which are not done on purpose, can be reduced by more training and supervision. But violations, which are done on purpose, are the most difficult to change.