The primary goal of safety and risk management is to achieve and maintain a level of risk that is as low as reasonably practicable while accomplishing the organization's objectives. This is achieved by selecting and applying appropriate risk treatments using a hierarchy approach.
A fundamental concept within operational risk management is the ranking of hazard controls and risk treatment strategies known as the hierarchy of controls.
Various hierarchy of controls models exist, each having slight differences in control options and applications, presenting some confusion to the user. A new risk reduction hierarchy model is presented that incorporates inherently safer design strategies in a more comprehensive format accompanied by a decision tree.
The primary goal for an OSH professional is to reduce operational risk to a level that is considered as low as reasonably practicable (ALARP). ANSI/ASSP Z590.3-2011 (R2106), Prevention Through Design, defines ALARP as "that level of risk which can be further lowered only by an increase in resource expenditure that is disproportionate in relation to the resulting decrease in risk." Achieving and maintaining ALARP should be the goal, the state of being in all workplaces. One concept OSH professionals use to achieve the state of ALARP is the application of risk reduction strategies according to the hierarchy of controls.
OSH professionals have traditionally ranked control measures according to their effectiveness and reliability in removing or controlling hazards. This concept has become known as the hierarchy of controls. It is thought to have its origins in occupational health and industrial hygiene beginning in the late 1940s. In Advanced Safety Management, Manuele (2008) cites the third edition of National Safety Council's 1955 Accident Prevention Manual as an early source of a hierarchy of controls.
The concept of ranking risk reduction strategies has developed over the years. Originally, the principle of the hierarchy of controls was to control the hazard as close to the source as possible, with
engineering as the top control measure and
PPE as the second option.