Question: Controlling exposures to occupational hazards is the fundamental method of protecting workers. Traditionally, a “hierarchy of controls” has been used as a means of determining how to implement feasible and effective control solutions. What is the so-called “hierarchy of controls”?
Answer: The cited reference describes the “hierarchy of controls” as follows (from highest/safest control to lowest):
Elimination and substitution followed by engineering controls, followed by administrative controls, followed by personal protective equipment. The idea behind this hierarchy is that the control methods at the left (elimination/substitution) are potentially more effective and protective than those at the right (PPE). Following this hierarchy normally leads to the implementation of inherently safer systems, where the risk of illness or injury has been substantially reduced. (https://www.cdc.gov/niosh/topics/hierarchy/; accessed August 2017)