Applying the Hierarchy of Controls for COVID-19

April 9, 2020

Applying the Hierarchy of Controls for COVID-19

Controlling exposures to hazards is the fundamental method of protecting people. Traditionally, a hierarchy of controls has been used as a means of determining how to implement feasible and effective control solutions.

We will apply the hierarchy of controls to the biohazard known as COVID-19. Starting at the top of the hierarchy of controls is the most effective means of control is elimination – this is why we are all physically distancing from each other to remove ourselves from the hazard. 

Elimination: Social Distancing & COVID-19

For essential workers in hospitals and grocery stores this means to stay away from the workplace when a person is ill or symptomatic, or potentially exposed to the virus. For the general public, eliminating movement in public to reduce contact with other people reduces the chance of transmission.  

Social isolation is one of our best tools to reduce the spread of infection; it is an important control for this virus because even those who are asymptomatic (not showing any signs of infection) can, unknowingly, spread the virus at any time they leave their home.

Substitution: The Hunt for a Vaccination

The next level of the hierarchy of controls is substitution – replacing the hazardous agent with a less hazardous one. In this case of COVID-19 it does not apply.  How about vaccination? The inactivated virus becomes a form of protection. Still, a vaccine is not yet available. However, in future immunizations will be an important part of maintaining a healthy workforce.

Engineering Controls: Distancing Essential Workers from the Virus

The next level of control is engineering controls – separating the workers from the hazard. In hospitals, they use dedicated ventilation systems to remove the air from a room. In grocery stores you may see plastic shields around cashiers which offers a barrier between the workers and customers.  Control measures such as doorless restrooms, touchless sinks, motion-activated soap and towel dispensers are becoming more common in high traffic areas such as malls and airports.

Administrative Controls: Changing How People Work

The fourth level of the hierarchy is administrative controls – changing how people work. This includes work from home policies in workplaces where applicable. Reducing the number of customers in a store. Keeping workers and visitors at a distance. Online shopping and curbside pickup replace in-store shopping. You can implement handwashing rules even in your home, so people wash or sanitize hands as they enter the house, before and after all meals. Allowing mail or packages to sit for several days before handling it. Washing hands immediately after touching mail. Disinfecting the exterior of grocery containers, placing reusable grocery bags away for several days or washing them immediately. Washing your hands after handling groceries. Daily disinfection of high touch surfaces in your home. 

Personal Protective Equipment & COVID–19

The least effective control strategy in the hierarchy is PPE. This would include gloves and masks. PPE gives people a false sense of security and it is the last line of defence. Would the general public wear the PPE properly? Would they maintain the PPE to preserve cleanliness and function? When human factors come into play the answer is likely no. The consumption of PPE by the public would deplete the supply for those that need it most: health care staff and workers in close contact with vulnerable populations like long term care residents. 

Because the virus does not permeate the skin, hand washing is better to control than wearing gloves. Gloves offer no added protection and actually become another transmission vehicle for the virus. Social distancing is better controlled than wearing masks.  Homemade masks could also spread the virus when people touch the mask than their face or other surfaces or vice versa. Homemade masks provide only limited protection as they may remove some virus-containing droplets but cannot remove them to the extent that specifically designed PPE can. Thus, using homemade masks will not eliminate the risk. Furthermore, the use of PPE without some training and fit testing will reduce the effectiveness and may enhance risk if contaminated masks are not handled properly.