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{{short description|System used in industry to eliminate or minimize exposure to hazards }}
[[File:NIOSH’s_“Hierarchy_of_Controls_infographic”_as_SVG.svg|thumb|Infographic by [[Organization:National Institute for Occupational Safety and Health|NIOSH]]. Control methods at the top of graphic are potentially more effective and protective than those at the bottom. Following this hierarchy normally leads to the implementation of inherently safer systems, where the risk of illness or injury has been substantially reduced.<ref>{{Cite web|url=https://www.cdc.gov/niosh/topics/hierarchy/|title=Hierarchy of Controls|website=U.S. National Institute for Occupational Safety and Health|language=en-us|access-date=2017-01-31}}</ref>|275x275px]]
{{Occupational hazards}}

'''Hierarchy of hazard control''' is a system used in industry to prioritize possible interventions to minimize or eliminate exposure to hazards.<ref name="besmart">{{cite web|title=Hierarchy of Controls|publisher=Health and Safety Authority (Ireland)|url=http://besmart.hsa.ie/fs/doc/Hierarchy%20of%20Controls.15feb11.kb.pdf}}</ref><ref name="NYCOSH">{{cite web|url=http://nycosh.org/index.php?page=Hierarchy-of-Hazard-Controls |title=Hierarchy of Hazard Controls |website=New York Committee for Occupational Safety & Health |archive-url=https://web.archive.org/web/20120305133129/http://nycosh.org/index.php?page=Hierarchy-of-Hazard-Controls |archive-date=2012-03-05 |url-status=dead |access-date=2012-04-11 }}</ref><ref name="ohs handbook">{{cite web|url=http://ohshandbook.com.au/2012/01/20/how-the-hierarchy-of-control-can-help-you-fulfil-your-health-and-safety-duties/|archive-url=https://archive.today/20130114235809/http://ohshandbook.com.au/2012/01/20/how-the-hierarchy-of-control-can-help-you-fulfil-your-health-and-safety-duties/|url-status=dead|archive-date=2013-01-14|title=How the hierarchy of control can help you fulfil your health and safety duties|date=2012-01-20|publisher=Occupational Health & Safety Handbook|access-date=2012-04-11}}</ref><ref name="OHS answers">{{cite web|url=http://www.ccohs.ca/oshanswers/hsprograms/hazard_control.html|title=Hazard Control|date=2006-04-20|website=Canadian Centre for Occupational Health and Safety|access-date=2012-04-11}}</ref><ref name="cdc">{{cite web|url=https://www.cdc.gov/niosh/engcontrols/|title=Engineering Controls|website=U.S. National Institute for Occupational Safety and Health|access-date=2012-04-11}}</ref><ref name="hse UK">{{cite web|url=http://www.hse.gov.uk/treework/safety-topics/height.htm#control|title=Tree Work – Working at height|website=UK Health and Safety Executive|access-date=2012-04-11}}</ref><ref name="safework south australia">{{cite web|url=http://www.safework.sa.gov.au/contentPages/EducationAndTraining/TrainingKits/WHSTrainingResourceKit/whsKit/top3_7.htm |title=Hierarchy of control diagram |website=Safework SA |archive-url=https://web.archive.org/web/20140327051012/http://www.safework.sa.gov.au/contentPages/EducationAndTraining/TrainingKits/WHSTrainingResourceKit/whsKit/top3_7.htm |archive-date=2014-03-27 |url-status=dead |access-date=2012-04-11 }}</ref><ref name="saunions">{{cite web|url=http://www.saunions.org.au/ohs/hierachy_of_controls.htm|title=Hierarchy of Controls|website=SA Unions|access-date=2012-04-11|archive-url=https://web.archive.org/web/20050623055058/http://www.saunions.org.au/ohs/hierachy_of_controls.htm|archive-date=2005-06-23|url-status=dead}}</ref><ref name="workcover">[http://www.workcover.nsw.gov.au/formspublications/publications/Documents/hierarchy_of_controls_5620.pdf MANUAL HANDLING HIERARCHY OF CONTROLS] {{webarchive|url=https://web.archive.org/web/20120907025043/http://www.workcover.nsw.gov.au/formspublications/publications/Documents/hierarchy_of_controls_5620.pdf |date=2012-09-07 }}</ref><ref>{{Cite web|url=http://www.workcover.nsw.gov.au/formspublications/publications/Documents/hierarchy_of_controls_5620.pdf |title=Manual Handling: Hierarchy of Controls |website=WorkCover New South Wales |archive-url=https://web.archive.org/web/20141222123533/http://www.workcover.nsw.gov.au/formspublications/publications/Documents/hierarchy_of_controls_5620.pdf |archive-date=2014-12-22 |url-status=dead }}</ref><ref name="worksafe victoria">{{cite web|url=http://www.worksafe.vic.gov.au/forms-and-publications/forms-and-publications/hazard-identification,-risk-assessment-and-risk-control-in-the-workplace |title=Hazard identification, risk assessment & risk control in the workplace |website=WorkSafe Victoria |archive-url=https://web.archive.org/web/20131023101547/http://www.worksafe.vic.gov.au/forms-and-publications/forms-and-publications/hazard-identification%2C-risk-assessment-and-risk-control-in-the-workplace |archive-date=2013-10-23 |url-status=dead |access-date=2012-04-11 }}</ref> It is a widely accepted system promoted by numerous safety organizations. This concept is taught to [[Social:Management|managers]] in industry, to be promoted as standard practice in the workplace. It has also been used to inform public policy, in fields such as road safety.<ref>{{Cite journal|last1=McLeod|first1=Sam|last2=Curtis|first2=Carey|date=2020-12-21|title=Integrating urban road safety and sustainable transportation policy through the hierarchy of hazard controls|url=https://doi.org/10.1080/15568318.2020.1858376|journal=International Journal of Sustainable Transportation|volume=16 |issue=2 |pages=166–180|doi=10.1080/15568318.2020.1858376|s2cid=234431488|issn=1556-8318}}</ref> Various illustrations are used to depict this system, most commonly a triangle.

The hazard controls in the hierarchy are, in order of decreasing priority:
* [[Hazard elimination|Elimination]]
* [[Hazard substitution|Substitution]]
* [[Engineering:Engineering controls|Engineering controls]]
* [[Engineering:Administrative controls|Administrative controls]]
* [[Social:Personal protective equipment|Personal protective equipment]]
The priority should not be confused with effectiveness. The system is not based on evidence about effectiveness but based on the assumed burden on workers. If elimination of the hazard is possible, it frees workers of being aware of the hazard and protecting themselves. That is the basis for the priority. Substitution has less priority than elimination because the substitute can possibly also come with a hazard. Engineering controls depend on a well-functioning system and human behaviour. Administrative controls and personal protective equipment are always dependent on human behaviour which makes these controls less reliable.

==Components of the hierarchy==
===Elimination===
{{Main article|Hazard elimination}}
Physical removal of the hazard is the most effective hazard control.<ref name="OHS answers" /> For example, if employees must work high above the ground, the hazard can be eliminated by moving the piece they are working on to ground level to eliminate the need to work at heights. However, often elimination of the hazard is not possible because the task explicitly involves handling a hazardous agent. For example in health care when treating patients with infectious diseases, exposure to the infectious agent is not possible to eliminate. The same holds for removing asbestos where handling the hazardous agent is the core of the task.<ref name=NYCOSH />

===Substitution===
{{Main article|Hazard substitution}}
[[Image:DDTDichlordiphényltrichloréthane7.JPG|thumb|right|150px|This pesticide contains [[Chemistry:DDT|DDT]]; an effective substitution would be to replace it with a green pesticide.]]

Substitution, the second most effective hazard control, involves replacing something that produces a hazard with something that does not produce a hazard or produces a lesser hazard—for example, replacing solvent-based paint with water-based paint. To be an effective control, the new product must not produce [[Social:Unintended consequences|unintended consequences]]. Because airborne dust can be hazardous, if a product can be purchased with a larger [[Chemistry:Particle size|particle size]],  the smaller product may effectively be substituted with the larger product.<ref name="OHS answers" />

===Engineering controls===
{{Main article|Engineering:Engineering controls}}
The third most effective means of controlling hazards is engineered controls.  These do not eliminate hazards, but rather isolate people from hazards.<ref name="NYCOSH" />  Capital costs of engineered controls tend to be higher than less effective controls in the hierarchy, however they may reduce future costs.<ref name="cdc" /> For example, a crew might build a work platform rather than purchase, replace, and maintain fall arrest equipment.  "Enclosure and isolation" creates a physical barrier between personnel and hazards, such as using remotely controlled equipment.  [[Organization:Fume hood|Fume hood]]s can remove airborne contaminants as a means of engineered control.<ref name="OHS answers" />

===Administrative controls===
This sign warns people that there are explosives in [[Walker Lake (Nevada)|Walker Lake; however, it cannot prevent people from swimming in it.|thumb|right]]{{Main article|Administrative controls}}
Administrative controls are changes to the way people work. Examples of administrative controls include procedure changes, employee training, and installation of signs and warning labels (such as those in the Workplace Hazardous Materials Information System).<ref name=NYCOSH />  Administrative controls do not remove hazards, but limit or prevent people's exposure to the hazards, such as completing road construction at night when fewer people are driving.<ref name="OHS answers" />

===Personal protective equipment===
{{main|Social:Personal protective equipment}}
Personal protective equipment (PPE) includes gloves, [[Engineering:Nomex|Nomex]] clothing, overalls, [[Chemistry:Tyvek|Tyvek]] suits, [[Engineering:Respirator|respirator]]s, [[Engineering:Hard hat|hard hat]]s, safety glasses, high-visibility clothing, and safety footwear.  PPE is often the most important means of controlling hazards such as in health care and asbestos removal. Even though almost always also other prevention strategies are possible these do not reduce the risks to safe levels. PPE must then be used to still further reduce risks to safe levels. However, considerable efforts are needed to use PPE effectively such as training in donning and doffing or testing the equipment.<ref name="OHS answers" />  Additionally, some PPE, such as respirators, increase physiological effort to complete a task and, therefore, may require medical examinations to ensure workers can use the PPE without risking their health.

== Role in Prevention through Design ==
The hierarchy of controls is a core component of [[Engineering:Prevention through design|Prevention through Design]], the concept of applying methods to minimize [[Social:Occupational safety and health|occupational hazards]] early in the design process. Prevention through Design emphasizes addressing hazards at the top of the hierarchy of controls (mainly through elimination and substitution) at the earliest stages of project development.<ref>{{Cite web|url=https://www.cdc.gov/niosh/topics/hierarchy/default.html|title=CDC - Hierarchy of Controls - NIOSH Workplace Safety and Health Topic|website=www.cdc.gov|language=en-us|access-date=2017-08-07}}</ref>

== Variations on the NIOSH Control Hierarchy ==
While the control hierarchy shown above is traditionally used in the United States and Canada, other countries or entities may use a slightly different structure. In particular, some add isolation above engineering controls instead of combining the two.<ref>{{Cite web|title=Hazards and Risk|url=https://www.hsa.ie/eng/Topics/Hazards/https:/www.hsa.ie/eng/Topics/Hazards/Hazards_and_Risk.html|access-date=2021-11-10|website=Health and Safety Authority|language=en}}</ref><ref>{{Cite web|title=The hierarchy of control - WorkSafe|url=https://www.worksafe.vic.gov.au/hierarchy-control|access-date=2021-11-10|website=www.worksafe.vic.gov.au|language=en}}</ref><ref>{{Cite web|title=Hierarchy of controls applied to dangerous substances: OSHwiki|url=https://oshwiki.eu/wiki/Hierarchy_of_controls_applied_to_dangerous_substances|access-date=2021-11-10|website=oshwiki.eu|language=en}}</ref> The variation of the hierarchy used in the ARECC decision-making framework and process for industrial hygiene (IH) includes modification of the material or procedure to reduce hazards or exposures (sometimes considered a subset of the [[Hazard substitution|hazard substitution]] option but explicitly considered there to mean that the efficacy of the modification for the situation at hand must be confirmed by the user). The ARECC version of the hierarchy also includes warnings as a distinct element to clarify the nature of the warning. In other systems, warnings are sometimes considered part of [[Engineering:Engineering controls|engineering controls]] and sometimes part of [[Engineering:Administrative controls|administrative controls]].

==See also==
* ARECC - Decision-making framework and process used in the field of industrial hygiene (IH) to anticipate and recognize hazards, evaluate exposures, and control and confirm protection from risks
* {{annotated link|Engineering:Prevention through design}}
* {{annotated link|Occupational exposure banding}}
* {{annotated link|Control banding}}
* Normalization of deviance – one reason people stop using effective prevention measures
* {{annotated link|Engineering:Safety engineering}}

==References==
{{NIOSH}}{{reflist}}

==External links==
* [http://www.ccohs.ca/oshanswers/hsprograms/hazard_control.html Canadian Centre for Occupational Health & Safety document]
* [https://oshwiki.eu/wiki/Hierarchy_of_prevention_and_control_measures Hierarchy of prevention and control measures] on OSH Wiki (EU)

{{Occupational safety and health}}

[[Category:Hazard analysis]]

{{Sourceattribution|Hierarchy of hazard controls}}