Hierarchy of hazard controls
Hierarchy of hazard control is a system used in industry to prioritize possible interventions to minimize or eliminate exposure to hazards. 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. Various illustrations are used to depict this system, most commonly a triangle.
The hazard controls in the hierarchy are, in order of decreasing priority:
The system is not based on evidence about effectiveness but based on If elimination of the hazard is possible, it frees workers of being aware of the hazard and protecting themselves. 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.
History
During the 1990s TB outbreak, resulting from the HIV/AIDS in [the United States|HIV epidemic in the United States], the hierarchy of controls was described as a way for healthcare workers to mitigate their exposure to TB. Starting from page 10, the hierarchy can be summarized, from most to least preferable, like this:- "Substitution" - Avoids the hazard, which is not possible in a healthcare setting.
- "Contain at their source" - Using administrative controls, screen for a given health hazard.
- * This can include source control, which can involve masking an infected patient.
- "Engineering controls" - This usually involves configuring isolation rooms and HVAC systems to prevent the spread of infection.
- "Establish barriers" - Personal protective equipment, with respirators.
Components of the hierarchy
Elimination
Physical removal of the hazard is the most effective hazard control. 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.Substitution
Image:DDTDichlordiphényltrichloréthane7.JPG|thumb|right|150px|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.
Engineering controls
The third most effective means of controlling hazards is engineered controls. These do not eliminate hazards, but rather isolate people from hazards. Capital costs of engineered controls tend to be higher than less effective controls in the hierarchy, however they may reduce future costs. 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.Administrative controls
[image:Walker_lake_munitions_warning.JPG|This sign warns people that there are explosives in Walker Lake; however, it cannot prevent people from swimming in it.|thumb|right]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. 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.