Hierarchy of hazard controls

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Hazard control methods at the top of the graphic are potentially more effective and protective than those at the bottom. Following this hierarchy of controls normally leads to the implementation of inherently safer systems, where the risk of illness or injury has been substantially reduced. NIOSH's "Hierarchy of Controls infographic" as SVG.svg
Hazard control methods at the top of the graphic are potentially more effective and protective than those at the bottom. Following this hierarchy of controls normally leads to the implementation of inherently safer systems, where the risk of illness or injury has been substantially reduced.

Hierarchy of hazard control is a system used in industry to prioritize possible interventions to minimize or eliminate exposure to hazards. [a] It is a widely accepted system promoted by numerous safety organizations. This concept is taught to 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. [13] Various illustrations are used to depict this system, most commonly a triangle.

Contents

The hazard controls in the hierarchy are, in order of decreasing priority:

The system is not based on evidence of effectiveness; rather, it relies on whether the elimination of hazards is possible. Eliminating hazards allows workers to be free from the need to recognize and protect themselves against these dangers. Substitution is given lower priority than elimination because substitutes may also present hazards. Engineering controls depend on a well-functioning system and human behavior, while administrative controls and personal protective equipment are inherently reliant on human actions, making them less reliable.

History

The NIOSH TB guide describes an early version of the Hierarchy of Controls (On Wikisource) Niosh tb guidelines.pdf
The NIOSH TB guide describes an early version of the Hierarchy of Controls (On Wikisource)

During the 1990s TB outbreak, resulting from the HIV epidemic in the United States, the hierarchy of controls was described as a way for healthcare workers to mitigate their exposure to TB. The hierarchy can be summarized, from most to least preferable, as the following list states: [14]

Today's hierarchy has several differences, however keeping the original idea.

Components of the hierarchy

Elimination

Physical removal of the hazard is the most effective hazard control. [5] 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, construction professionals cannot remove the danger of asbestos when handling the hazardous agent is the core of the task. [3]

The most effective control measure is eliminating the hazard and its associated risks entirely. The simplest way to do this is by not introducing the hazard in the first place. For instance, the risk of falling from a height can be eliminated by performing the task at ground level. Eliminating hazards is often more cost-effective and feasible during the design or planning phase of a product, process, or workplace. At this stage, there’s greater flexibility to design out hazards or incorporate risk controls that align with the intended function. [15] Employers can also eliminate hazards by completely removing them—such as clearing trip hazards or disposing of hazardous chemicals, thus eliminating the risks they pose. If eliminating a hazard compromises the ability to produce the product or deliver the service, it's crucial to eliminate as many risks associated with the hazard as possible.

Substitution

This pesticide contains DDT; an effective substitution would be to replace it with a green pesticide. DDTDichlordiphenyltrichlorethane7.JPG
This pesticide contains 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. However, to be an effective control, the new product must not produce unintended consequences. For example, if a product can be purchased with a larger particle size, the smaller product may effectively be substituted with the larger product due to airborne dust having the possibility of being hazardous. [5]

Eliminating hazards and substituting safer alternatives can be challenging to implement within existing processes. These strategies are most effective when applied during the design or development phases of a workplace, tool, or procedure. At this stage, they often represent the most straightforward and cost-effective solutions. Additionally, they present a valuable opportunity when selecting new equipment or methods. The Prevention through Design approach emphasizes integrating safety considerations into the design of work tools, operations, and environments to enhance overall safety and efficiency. [16]

Engineering controls

The third most effective means of controlling hazards is engineered controls. These do not eliminate hazards, but rather isolate people from hazards. [3] Capital costs of engineered controls tend to be higher than less effective controls in the hierarchy, however they may reduce future costs. [6] A main part of engineering controls, "enclosure and isolation," creates a physical barrier between personnel and hazards, such as using remotely controlled equipment. As an example, fume hoods can remove airborne contaminants as a means of engineered control. [5]

Effective engineering controls are integral to the original equipment design and work to eliminate or block hazards at the source before they reach workers. They are designed to prevent users from modifying or tampering with the controls and require minimal action from users to function effectively. These controls operate seamlessly without disrupting the workflow or complicating tasks. While they may have higher initial costs compared to administrative controls or personal protective equipment (PPE), they often result in lower long-term operating expenses, especially when safeguarding multiple workers and potentially saving costs in other operational areas. [16]

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. [3] 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. [5]

Administrative controls are ranked lower than elimination, substitution, and engineering controls because they do not directly remove or reduce workplace hazards. Instead, they manage workers' exposure by setting rules like limiting work times in contaminated areas. However, these measures have limitations since they don't address the hazard itself. Where possible, administrative controls should be combined with other control measures. [17]

Examples of administrative controls include:

Personal protective equipment

Personal protective equipment (PPE) includes gloves, Nomex clothing, overalls, Tyvek suits, respirators, hard hats, safety glasses, high-visibility clothing, and safety footwear. PPE is often the most important means of controlling hazards in fields such as health care and asbestos removal. However, considerable efforts are needed to use PPE effectively, such as training in donning and doffing or testing the equipment. [5] 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.

Employers should not depend solely on personal protective equipment (PPE) [18] to manage hazards when more effective controls are available. While PPE can be beneficial, its effectiveness relies on correct and consistent use, and it may incur significant costs over time, especially when used daily for multiple workers. Employers must provide PPE when other control measures are still being developed or cannot adequately reduce hazardous exposure to safe levels. [16] Personal Protective Equipment (PPE) minimizes risks to health and safety when worn correctly, including items like earplugs, goggles, respirators, and gloves. However, PPE and administrative controls don't eliminate hazards at their source, relying instead on human behavior and supervision. As a result, they are among the least effective methods for risk reduction when used alone. [15]

Role in prevention through design

The hierarchy of controls is a core component of Prevention through Design, the concept of applying methods to minimize 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. [16]

NIOSH’s Prevention through Design Initiative comprises “all of the efforts to anticipate and design out hazards to workers in facilities, work methods and operations, processes, equipment, tools, products, new technologies, and the organization of work.” [19]

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. [20] [21] [22] 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 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 controls and sometimes part of administrative controls.

Use of hierarchical controls

The hierarchy of controls serves as a valuable tool for safety professionals to determine the most effective methods for managing specific hazards. By following this hierarchy, employers can ensure they are implementing the best measures to protect their employees from potential risks.

When encountering a hazard in the workplace, the hierarchy of hazard control provides a systematic approach to identify the most appropriate actions for controlling or eliminating that hazard. Additionally, it aids in developing a comprehensive hazard control plan for implementing the chosen measures effectively in the workplace. [23]

It is important to be aware of the following when using the hierarchy of controls:

  1. Use interim controls: If more time is needed to implement long-term solutions, the hierarchy of controls should be used from the top down as interim controls in the meantime.
  2. Avoid introducing new hazards: Keep in mind is that the selected controls should never directly or indirectly introduce new hazards. Make sure to perform a thorough safety analysis before implementing the selected controls.
  3. Use a combination of controls: If there is no single method that will fully protect workers, then a combination of controls should be used.

See also

Notes

Related Research Articles

<span class="mw-page-title-main">Personal protective equipment</span> Equipment designed to help protect an individual from hazards

Personal protective equipment (PPE) is protective clothing, helmets, goggles, or other garments or equipment designed to protect the wearer's body from injury or infection. The hazards addressed by protective equipment include physical, electrical, heat, chemical, biohazards, and airborne particulate matter. Protective equipment may be worn for job-related occupational safety and health purposes, as well as for sports and other recreational activities. Protective clothing is applied to traditional categories of clothing, and protective gear applies to items such as pads, guards, shields, or masks, and others. PPE suits can be similar in appearance to a cleanroom suit.

<span class="mw-page-title-main">Blood-borne disease</span> Medical condition

A blood-borne disease is a disease that can be spread through contamination by blood and other body fluids. Blood can contain pathogens of various types, chief among which are microorganisms, like bacteria and parasites, and non-living infectious agents such as viruses. Three blood-borne pathogens in particular, all viruses, are cited as of primary concern to health workers by the CDC-NIOSH: HIV, hepatitis B (HVB), & hepatitis C (HVC).

<span class="mw-page-title-main">National Institute for Occupational Safety and Health</span> US federal government agency

The National Institute for Occupational Safety and Health is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the Centers for Disease Control and Prevention (CDC) within the U.S. Department of Health and Human Services. Despite its name, it is not part of either the National Institutes of Health nor OSHA. Its current director is John Howard.

Occupational noise is the amount of acoustic energy received by an employee's auditory system when they are working in the industry. Occupational noise, or industrial noise, is often a term used in occupational safety and health, as sustained exposure can cause permanent hearing damage. Occupational noise is considered an occupational hazard traditionally linked to loud industries such as ship-building, mining, railroad work, welding, and construction, but can be present in any workplace where hazardous noise is present.

<span class="mw-page-title-main">Occupational hygiene</span> Management of workplace health hazards

Occupational hygiene or industrial hygiene (IH) is the anticipation, recognition, evaluation, control, and confirmation (ARECC) of protection from risks associated with exposures to hazards in, or arising from, the workplace that may result in injury, illness, impairment, or affect the well-being of workers and members of the community. These hazards or stressors are typically divided into the categories biological, chemical, physical, ergonomic and psychosocial. The risk of a health effect from a given stressor is a function of the hazard multiplied by the exposure to the individual or group. For chemicals, the hazard can be understood by the dose response profile most often based on toxicological studies or models. Occupational hygienists work closely with toxicologists (see Toxicology) for understanding chemical hazards, physicists (see Physics) for physical hazards, and physicians and microbiologists for biological hazards (see Microbiology, Tropical medicine, Infection). Environmental and occupational hygienists are considered experts in exposure science and exposure risk management. Depending on an individual's type of job, a hygienist will apply their exposure science expertise for the protection of workers, consumers and/or communities.

The permissible exposure limit is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits were established by the Occupational Safety and Health Administration (OSHA). Most of OSHA's PELs were issued shortly after adoption of the Occupational Safety and Health (OSH) Act in 1970.

Chemical hazards are hazards present in hazardous chemicals and hazardous materials. Exposure to certain chemicals can cause acute or long-term adverse health effects. Chemical hazards are usually classified separately from biological hazards (biohazards). Chemical hazards are classified into groups that include asphyxiants, corrosives, irritants, sensitizers, carcinogens, mutagens, teratogens, reactants, and flammables. In the workplace, exposure to chemical hazards is a type of occupational hazard. The use of personal protective equipment may substantially reduce the risk of adverse health effects from contact with hazardous materials.

A job safety analysis (JSA) is a procedure that helps integrate accepted safety and health principles and practices into a particular task or job operation. The goal of a JSA is to identify potential hazards of a specific role and recommend procedures to control or prevent these hazards.

A recommended exposure limit (REL) is an occupational exposure limit that has been recommended by the United States National Institute for Occupational Safety and Health. The REL is a level that NIOSH believes would be protective of worker safety and health over a working lifetime if used in combination with engineering and work practice controls, exposure and medical monitoring, posting and labeling of hazards, worker training and personal protective equipment. To formulate these recommendations, NIOSH evaluates all known and available medical, biological, engineering, chemical, trade, and other information. Although not legally enforceable limits, RELS are transmitted to the Occupational Safety and Health Administration (OSHA) or the Mine Safety and Health Administration (MSHA) of the U.S. Department of Labor for use in promulgating legal standards.

Workplace health surveillance or occupational health surveillance (U.S.) is the ongoing systematic collection, analysis, and dissemination of exposure and health data on groups of workers. The Joint ILO/WHO Committee on Occupational Health at its 12th Session in 1995 defined an occupational health surveillance system as "a system which includes a functional capacity for data collection, analysis and dissemination linked to occupational health programmes".

<span class="mw-page-title-main">Physical hazard</span> Hazard due to a physical agent

A physical hazard is an agent, factor or circumstance that can cause harm with contact. They can be classified as type of occupational hazard or environmental hazard. Physical hazards include ergonomic hazards, radiation, heat and cold stress, vibration hazards, and noise hazards. Engineering controls are often used to mitigate physical hazards.

<span class="mw-page-title-main">Occupational hearing loss</span> Form of hearing loss

Occupational hearing loss (OHL) is hearing loss that occurs as a result of occupational hazards, such as excessive noise and ototoxic chemicals. Noise is a common workplace hazard, and recognized as the risk factor for noise-induced hearing loss and tinnitus but it is not the only risk factor that can result in a work-related hearing loss. Also, noise-induced hearing loss can result from exposures that are not restricted to the occupational setting.

A psychosocial hazard or work stressor is any occupational hazard related to the way work is designed, organized and managed, as well as the economic and social contexts of work. Unlike the other three categories of occupational hazard, they do not arise from a physical substance, object, or hazardous energy.

Engineering controls are strategies designed to protect workers from hazardous conditions by placing a barrier between the worker and the hazard or by removing a hazardous substance through air ventilation. Engineering controls involve a physical change to the workplace itself, rather than relying on workers' behavior or requiring workers to wear protective clothing.

The health and safety hazards of nanomaterials include the potential toxicity of various types of nanomaterials, as well as fire and dust explosion hazards. Because nanotechnology is a recent development, the health and safety effects of exposures to nanomaterials, and what levels of exposure may be acceptable, are subjects of ongoing research. Of the possible hazards, inhalation exposure appears to present the most concern, with animal studies showing pulmonary effects such as inflammation, fibrosis, and carcinogenicity for some nanomaterials. Skin contact and ingestion exposure, and dust explosion hazards, are also a concern.

Hazard elimination is a hazard control strategy based on completely removing a material or process causing a hazard. Elimination is the most effective of the five members of the hierarchy of hazard controls in protecting workers, and where possible should be implemented before all other control methods. Many jurisdictions require that an employer eliminate hazards if it is possible, before considering other types of hazard control.

Hazard substitution is a hazard control strategy in which a material or process is replaced with another that is less hazardous. Substitution is the second most effective of the five members of the hierarchy of hazard controls in protecting workers, after elimination. Substitution and elimination are most effective early in the design process, when they may be inexpensive and simple to implement, while for an existing process they may require major changes in equipment and procedures. The concept of prevention through design emphasizes integrating the more effective control methods such as elimination and substitution early in the design phase.

<span class="mw-page-title-main">Engineering controls for nanomaterials</span>

Engineering controls for nanomaterials are a set of hazard control methods and equipment for workers who interact with nanomaterials. Engineering controls are physical changes to the workplace that isolate workers from hazards, and are considered the most important set of methods for controlling the health and safety hazards of nanomaterials after systems and facilities have been designed.

Anticipate, recognize, evaluate, control, and confirm (ARECC) is a 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. ARECC supports exposure- and population-informed hazard assessment, hazard- and population-informed exposure assessment, hazard- and exposure-informed population assessment, and risk-informed decision making in any endeavor.

<span class="mw-page-title-main">Workplace hazard controls for COVID-19</span> Prevention measures for COVID-19

Hazard controls for COVID-19 in workplaces are the application of occupational safety and health methodologies for hazard controls to the prevention of COVID-19. Multiple layers of controls are recommended, including measures such as remote work and flextime, personal protective equipment (PPE) and face coverings, social distancing, and enhanced cleaning programs. Recently, engineering controls have been emphasized, particularly stressing the importance of HVAC systems meeting a minimum of 5 air changes per hour with ventilation or MERV-13 filters, as well as the installation of UVGI systems in public areas.

References

  1. ↑ "Hierarchy of Controls". U.S. National Institute for Occupational Safety and Health . Retrieved 2017-01-31.
  2. ↑ "Hierarchy of Controls" (PDF). Health and Safety Authority (Ireland). Archived from the original (PDF) on 2012-09-07. Retrieved 2012-04-11.
  3. 1 2 3 4 "Hierarchy of Hazard Controls". New York Committee for Occupational Safety & Health. Archived from the original on 2012-03-05. Retrieved 2012-04-11.
  4. ↑ "How the hierarchy of control can help you fulfil your health and safety duties". Occupational Health & Safety Handbook. 2012-01-20. Archived from the original on 2013-01-14. Retrieved 2012-04-11.
  5. 1 2 3 4 5 6 "Hazard Control". Canadian Centre for Occupational Health and Safety. 2006-04-20. Retrieved 2012-04-11.
  6. 1 2 "Engineering Controls". U.S. National Institute for Occupational Safety and Health. Retrieved 2012-04-11.
  7. ↑ "Tree Work – Working at height". UK Health and Safety Executive. Retrieved 2012-04-11.
  8. ↑ "Hierarchy of control diagram". Safework SA. Archived from the original on 2014-03-27. Retrieved 2012-04-11.
  9. ↑ "Hierarchy of Controls". SA Unions. Archived from the original on 2005-06-23. Retrieved 2012-04-11.
  10. ↑ MANUAL HANDLING HIERARCHY OF CONTROLS Archived 2012-09-07 at the Wayback Machine
  11. ↑ "Manual Handling: Hierarchy of Controls" (PDF). WorkCover New South Wales. Archived from the original (PDF) on 2014-12-22.
  12. ↑ "Hazard identification, risk assessment & risk control in the workplace". WorkSafe Victoria. Archived from the original on 2013-10-23. Retrieved 2012-04-11.
  13. ↑ McLeod, Sam; Curtis, Carey (2020-12-21). "Integrating urban road safety and sustainable transportation policy through the hierarchy of hazard controls". International Journal of Sustainable Transportation. 16 (2): 166–180. doi:10.1080/15568318.2020.1858376. ISSN   1556-8318. S2CID   234431488.
  14. ↑ NIOSH Recommended Guidelines for Personal Respiratory Protection of Workers in Health-care Facilities Potentially Exposed to Tuberculosis. 1992.
  15. 1 2 "The hierarchy of control". WorkSafe Victoria. Retrieved 2024-10-22.
  16. 1 2 3 4 "CDC - Hierarchy of Controls - NIOSH Workplace Safety and Health Topic". www.cdc.gov. Retrieved 2017-08-07.
  17. ↑ Government of Canada, Canadian Centre for Occupational Health and Safety (2024-08-14). "CCOHS: Hazard and Risk - Hierarchy of Controls". www.ccohs.ca. Retrieved 2024-10-22.
  18. ↑ "Personal Protective Equipment".
  19. ↑ "Understanding the Hierarchy of Controls in Workplace Safety | Safety+Health". www.safetyandhealthmagazine.com. Retrieved 2024-10-18.
  20. ↑ "Hazards and Risk". Health and Safety Authority. Retrieved 2021-11-10.
  21. ↑ "The hierarchy of control - WorkSafe". www.worksafe.vic.gov.au. Retrieved 2021-11-10.
  22. ↑ "Hierarchy of controls applied to dangerous substances: OSHwiki". oshwiki.eu. Retrieved 2021-11-10.
  23. ↑ Team, Safety International (2022-09-05). "The 5 Levels of the Hierarchy of Controls Explained". Safety International, LLC. Retrieved 2024-10-22.
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