The Hierarchy of Controls

Let’s take a moment to talk about the hierarchy of controls, a process to limit or control risk.  You consider how to decrease the likelihood (how often it might happen) or consequence (how badly someone/something may be hurt or damaged) of a risk, or both, starting with the most effective control measure and working through the list.  Sometimes, one measure will completely remove the risk.  Sometimes using two or three might.  And sometimes, even with all five measures considered and actions put in place, the risk still exists, albeit with a lower likelihood and/or consequence.

The first and most effective control measure is elimination.  Can we get rid of this particular risk?  If we can remove the risk, we remove any potential issue that the risk may have caused.  Second, we consider substitution.  Can we change the process, replace action A with action B, so that we get to the same end point without needing to encounter that risk?  Third is engineering.  Can we construct or install something physical to minimise the risk?  Fourth is administration.  Can we train people to work safely with the risk?  Finally, we look to personal protective equipment, or PPE.  What personal safeguards can we put in place to give individuals personal protection against a risk?

Now let’s use this process to attempt to control or limit the risk of COVID-19 spreading in our communities.

Can we eliminate the virus?  Technically, yes we can, but it involves eliminating virtually all person-to-person interaction.  If the virus is not passed to other people, its spread will cease and it will be eliminated.  This, however, would mean no contact between any people for weeks.  Sick people couldn’t see their doctors.  No one could go out to buy food.  People would die, not just of COVID, if we did this.  Elimination isn’t going to work all by itself.

What about substitution?  We can substitute our regular morning tea with a friend with a chat on the phone.  Do our grocery shopping online instead of in-store.  Have a telehealth consultation instead of visiting the doctor.  Substitution, like elimination, may reduce our exposure to the virus, but it won’t stop its spread entirely.

And so we move to engineering.  Supermarkets are putting up Perspex screens to divide cashiers from customers; customers from each other.  Direction arrows and floor markers assist in avoiding close interactions with others.  But there are still ample opportunities for transmission to occur.

Which leads us to administration.  Signs reminding you to wash your hands or advising how many people may be in the store.  “COVID-safe” procedures that outline how frequently a location is cleaned, and what type of sanitizer should be used.  Training for workers to ensure that the conditions of re-opening are met.  Even with all of this, there is still the possibility that the virus can spread, especially in areas with higher levels of diagnosed infections and community transmission.  

And finally, we come to personal protective equipment.  It is your last line of defence against a risk that cannot be adequately controlled without it.  It will not be effective if you don’t use it properly.  It will certainly not be effective if you don’t use it at all.  In the case of COVID, PPE for the general population is pretty basic.  Face masks (appropriate type, well-fitted and worn correctly).  Gloves (but don’t touch your face while wearing them). 

Masks are annoying.  Especially if you wear glasses.  Or it’s hot and humid.  Or when your nose starts to itch.  But if you are living in a location where medical and scientific professionals are mandating the use of masks, it’s because they’ve done a risk assessment and determined that the risk of COVID-19 spreading in that area cannot be adequately controlled by elimination, substitution, engineering and administration.  They are not trying to take away your rights.  They are not trying to control you.  They are trying to control risk and to decrease both likelihood and consequence of infection.  In the simplest terms, they are trying to make sure that you and yours do not get sick and die.