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Re-opening Institutions of Higher Learning and the Hierarchy of Controls

Koehler and Rule (2020) have published a novel schema for understanding how to think about environmental interventions to help minimize exposure to COVID-19. They bring the lens of environmental health to their discussion and have adapted NIOSH’s hierarchy of controls for this purpose. This same approach could be used to develop a structure in which to contemplate how to reduce faculty’s, staff’s, and students’ potential for contact with the novel coronavirus as we strive to re-open colleges and universities around the county. This approach could also be useful when planning on re-opening other businesses as well.

Figure 1 illustrates the five levels of control efforts in NOISH’s framework: elimination, substitution, engineering controls, administrative controls, and personal protective equipment or PPE. These levels are ranked in order of effectiveness in preventing hazardous exposures. Elimination is the most effective level, while PPE is the least effective way at managing contact with unsafe substances.

Upside down triangle showing the hierarchy of controls.

The best way to prevent exposure to COVID-19 is by physically eliminating the threat itself. For universities, this would mean faculty, staff, and students work exclusively from home, utilizing on-line and other forms of distance learning. Strict social distancing is the only way to guarantee that individuals will not come in contact with the novel coronavirus; they have to be physically isolated from its presence. Practicing complete isolation is particularly important for avoiding COVID-19 because it appears that infected persons are most contagious prior to developing symptoms (He et al. 2020). But, obviously, these controls also come at extremely high economic and personal costs, and it is unlikely that we as a society can maintain this approach for very long.

The second-best way to prevent exposure is by substitution. In traditional analyses of occupational safety, substitution would entail replacing the hazardous threat with something similar in function but less dangerous -- swapping a poisonous chemical for one that is benign, for example. Koehler and Rule (2020) claim that substitution is not applicable in the case of COVID-19.  I believe otherwise. While we cannot simply replace SARS-Cov-2 with a different virus, we can substitute our susceptible bodies for bodies that have been vaccinated, already contain sufficient numbers of SARS-Cov-2 antibodies, or have medicine in them that prevent the virus from replicating. That is, we can develop means by which SARS-Cov-2 cannot infect us, which would also prevent COVID-19 from developing. Vaccines, tests, and medicines are never 100% certain, which is one reason why substitution is less effective than elimination.

The third-most effective level is engineering controls; that is, finding ways to physically isolate people from the hazard by preventing them from coming in contact with it. We are now all probably familiar with the plexiglass barriers surrounding grocery store cashiers; this is one example of an engineering control. Universities could provide similar barriers by isolating personnel and students from one another through re-arranging classroom and office spaces to maintain at least 6’ between individuals at all times. Classrooms that used to hold 30 students in standard desks might be reconfigured to hold 10 students, each sitting individually at tables a minimum of 4’ wide that are spaced at least a 1’ apart from one another. Similarly, those working in cubicle spaces could move to private offices. Of course, such configurations will not maintain the same density of activity on campus, but it might be one strategy for at least a partial re-opening.

Administrative controls refer to changing the way work happens – staggering shifts instead of having everyone working 9-5 or allowing more time between classes so that students can avoid bunching up entering or exiting buildings, for example. These are often the cheapest to implement, though they may become expensive over the long term. Other examples include checking temperatures and symptoms prior to coming on campus; washing hands and disinfecting desks, tables, computers, and podiums between classes; and letting mail and other paper products sit for few days before delivering. Unlike the previous measures, they also require conscious effort on the part of employees or students to implement. But these controls can serve as a temporary solution until more effective means are put into place.

Finally, of course, there is protecting individuals with personal equipment: masks, gloves, etc. PPE is (usually) easy to procure and inexpensive; therefore, it can be seen as a first line of defense against an environmental hazard. However, it is only minimally effective and it too requires personal effort and compliance.

Administrative controls can be combined with engineering and some elimination controls to increase efficiency and to help contain control costs. For example, holding classes earlier in the day, later in the evening, and on weekends might be one way to increase the number of students an institution can teach during a semester while also maintaining staggered work hours for faculty and staff, social distance the in classroom, and extended time between courses. This set of controls could then be combined with increased on-line interactions to replace some face-to-face routinized or paper-based activities. Together, this larger set of elimination, engineering, and administrative strategies could help protect the health of the campus community as the substitution controls are being developed and tested.

Valerie Gray Hardcastle
St. Elizabeth Healthcare Executive Director, Institute for Health Innovation
Vice-President, Health Innovation
Northern Kentucky University


He, X., Lau, E., Wu, P., et al. (2020). Temporal dynamics in viral shedding and transmissibility of COVID-19. Nature Medicine.

Koehler, K., & Rule, A. (2020). Can a mask protect me? Homemade masks in the hierarchy of controls. Johns Hopkins Education and Research Center for Occupational Safety and Health. White paper.

NIOSH. (2015). Hierarchy of Controls. default.html.