Is the Hierarchy of Controls a Useful Tool Or Safety Trivia?


By Phil La Duke

In most cases when an author asks a question it’s rhetorical.  He or she isn’t really looking for an answer; rather, the author just wants to make a point.  That’s not the case with this particular article.  I have developed—both for internal use and for sale—scores of safety orientations, and contrary to the prevailing belief among safety “professionals” that it’s okay to steal such materials (mawkishly regurgitating the same material over and over again while presenting it as a new unique product) I start each one fresh and each time I do I ask myself “why do the learners need to know this?” and “what will they do with this knowledge once they have mastered it?”  Which leads me to the question about the Hierarchy of Controls, and frankly, I’m not sure it passes the sniff test of these two questions. Virtually every safety orientation includes the Hierarchy of Controls and I have to ask,why?

For those of you outside the safety trade or who are in the safety trade and have been living under a rock your entire career, the Hierarchy of Controls is a tool for protecting workers…except it doesn’t really.  It’s not a tool in the traditional sense, instead it is a conceptual approach to protecting workers that holds that some measures are more effective (and therefore more desirable) than other measures to protect workers.  Best of all it works…except when it doesn’t.

So let’s see if I can answer the two questions.  “Why do the learners need to know this?” and “what will the learners DO with this knowledge?”  When we’re conducting safety training if we ask for four hours we get two and generally have to split it with benefits, an explanation of the employee handbook and Lord knows what else.  I have seen the safety orientation whittled down to little more than a 15 minute pep talk, so in that context I have to wonder at the value of teaching the concept of the Hierarchy of Controls to front-line workers. I’ve gotten off on a bit of a tangent here, but back to our question “why do workers need to know this?” (I mean it is an absolute requirement in most of the safety orientations I have seen and commissioned to develop.) Proponents will insist that this is a valuable concept that teaches workers that the company puts in guards, rules, and PPE to protect them, but so what? When I worked the line, I assumed that the company designed safety measures into my job was a given. In my defense I was young and not yet jaded by the horrors I would witness over the subsequent 30 odd years.  Before anyone taps out an angry defense of the invaluable nature of the Hierarchy of Controls I’d just like to point out that I’ve not seen any study showing a correlation between understanding the Hierarchy of Controls and proper use of PPE, adherence to the safety rules, or even not by-passing safety devices. In my experience nobody has ever by-passed a safety interlock or failed to control hazardous energy because he or she had never heard of the Hierarchy of Controls.  One way I test the “does the learner need this” question is to ask “what bad thing will happen if the worker doesn’t know this” sadly, I am yet to come up with a single bad thing that will happen because the worker didn’t know about the Hierarchy of Controls.

Another issue with the Hierarchy of Controls has little to do with the Hierarchy of Controls itself and more to do with how it is taught.  We tend to teach it as “the best way to protect workers is to eliminate the hazard altogether, but sometimes that’s not possible so we move down the pyramid to the next level of protection: substitution. When substitution isn’t an option we use engineering controls like safety interlocks and guard…” and so on until we say something like “PPE is the last, and least effective way to protect you.  Now there’s a ringing endorsement for wearing cumbersome and uncomfortable gear—because it’s better than nothing.  Not only does teaching the Hierarchy of Controls not benefit workers in a practical way, it may create the impression that the company is doing the bare minimum to protect workers.  In practice, however, this is not how the Hierarchy of Controls is used.  We do try to eliminate or substitute the hazard for something benign or at least less hazardous, but then we use a combination of guarding, rules and signage, training, and PPE to form protective layers around the worker.  Explaining WHY we do this is so much more important than the philosophical concept that led us to those decisions.  This of course, is not the fault of the Hierarchy of Controls rather it is the fault of the instruction and explanation of the Hierarchy of Controls.  So why do people need to know about the Hierarchy of Controls? Because it teaches a necessary thought process that people need to make informed decisions about their safety.  “What bad thing might happen without this knowledge?” People could attempt to try work without the proper protection.

So putting in information that a) no protective measure is 100% failsafe and b) all protective measures rely at least to some extent on the active participation of the worker, and c) when these measures fail people often die or suffer crippling injuries; but can’t we just say that to front-line workers without filling the lesson with jargon.  One of the most difficult assignments in developing a training course is getting stuck with a subject matter expert, who ardently believes that people must be taught everything—to the minutest detail—about a subject.  It becomes one long fight with the expert over whether or not the person needs to understand the complexities of gravity to avoid slip, trip, and fall injuries.  I think to some extent we are all guilty of this type of behavior when it comes to the Hierarchy of Controls.  We know it. We like it, and we find it interesting therefore it most go into the training.  But in a real way it’s like teaching the principal of gravity to a swallow.  The swallow doesn’t care WHY it doesn’t fall out of the sky when it flies, it only cares that it doesn’t, that is to say, if swallows care about anything I’ve never been that emotionally close to a swallow to really say definitively.

On the other hand I like the Hierarchy of Controls; it makes safety seem scientific even if it isn’t. (And I’m sorry but it isn’t, half the safety community still believes that the best way to protect workers is to draw pentagrams on the floor.) The Hierarchy of Controls is easy to explain, it makes a super pyramid graphic (and who in safety doesn’t’ LOVE pyramids?), and above all it demonstrates that when it comes to safety we’re at least TRYING to approach things systematically.  The problem is this: who in that audience cares about our stupid pyramid, and frankly, it could create the impression that since PPE and Administrative controls are the least effective then there is little point to adhering to those policies.  So I guess at the end of the day I am left feeling as if we are better off using our limited time with that audience focusing on something other than the Hierarchy of Controls.