When we conduct work risk assessments, or while conducting incident investigations, one of your tasks is to try to determine corrective actions to prevent an accident from happening in the future.  In deciding what corrective measures should be implemented, Hierarchy of Controls can provide a framework for determining the most effective corrective actions to undertake.

The idea behind this hierarchy is that the control methods at the top of graphic are potentially more effective and protective than those at the bottom. Following this hierarchy normally leads to the implementation of inherently safer systems, where the risk of illness or injury has been substantially reduced.The Hierarchy breaks down as follows, with the most effective measures at the top of the pyramid and the least effective at the bottom.

1. Elimination/substitution. At the very top is the best way to deal with a safety hazard, which is to eliminate it altogether by preventing exposure to the hazard before it even occurs.  In substitution, you seek to permanently reduce the risk by substitute a less hazardous material or reduction of system energy. These are process design solutions that require a permanent change to how a job is performed.
2. Engineering controls. Change the structure of the work area to reduce exposure using safety devices or barriers.  An example would be to place a high fence around a dangerous location to prevent access or adding plywood walls around jackhammer activities to stop flying debris.
3. Administrative & work practice controls. Implement procedures that require workers to do things to reduce their exposure to a risk.  A lockout/tagout program is an example of an administrative control.  Set expectations that workers will engage in safe work practices. Another example is the use of warning signs, sirens and alarms.
4. Personal protective equipment (PPE). Make sure employees wear the proper protective clothing, gloves and eyeglasses for the job.  Examples are safety goggles, respirators, fall protection and hearing protection.

It is easy when conducting work risk assessment  or incident investigations to focus on the use of PPE and administrative controls because these are often the easiest to see and implement.  But because these rely on human behavior, they are not always the best approaches to take.  During your work risk assessments you  should look further up the pyramid to the higher order engineering solutions and risk elimination strategies, which can prevent the exposure to a risk before it occurs and reduce the risk without relying on fallible human behavior.