Some Safety Measures Are Better Than Others: The Hierarchy of Controls

We do a variety of things to maintain safety in the lab: wearing safety goggles, using biological safety cabinets, following specific procedures. Not all of these safety measures are equally protective. We safety professionals use the NIOSH Hierarchy of Controls as a guide to which sorts of safety measures are preferred over others.

The Hierarchy of Controls gives five levels of hazard control, from most preferred to least (wording from the NIOSH source above):

1.     Elimination: Physically remove the hazard.

2.     Substitution: Replace the hazard (presumably with something less hazardous).

3.     Engineering Controls: Isolate people from the hazard.

4.     Administrative Controls: Change the way people work.

5.     Personal Protective Equipment (PPE): Protect the worker with PPE.

The reason for this order of preference is effectiveness. Administrative controls, for example, depend on (unreliable) human beings to follow procedures and rules without fail; a built-in control, such as a fume hood, tends to be more effective.

If you have questions about the NIOSH Hierarchy of Controls, contact Dr. Daniel Kuespert, Homewood Laboratory Safety Advocate, at [email protected]. See Dr. Kuespert’s website,, for more safety information. As always, emergency response is available from Security at 410-516-7777.