In the last module, we examined the inspection and JHA processes to identify hazardous conditions and unsafe behaviors in the workplace. Once hazards have been identified, it's important that they be corrected immediately or as soon as possible.
Once hazardous conditions or unsafe behaviors are identified, it's important that the supervisor makes sure they are eliminated or reduced as soon as possible. To do this, one or a combination of the control strategies within the "Hierarchy of Controls" should be used.
In this module, we'll take a look at the Hierarchy of Controls and how they can effectively correct identified hazards. For more information on improving the safety management system, see Courses 704, Hazard Identification and Control and Course 716, Safety Management System Analysis.
Controlling hazards and behaviors are the two basic strategies for protecting workers. Controlling hazards are more effective than controlling behaviors, and for good reason. If you can eliminate the hazard, you don't have to worry about exposure due to human behavior. Traditionally, a "Hierarchy of Controls" has been used as a template for implementing feasible and effective controls.
ANSI/ASSP Z10-2019, Occupational Health and Safety Management Systems, and ISO 450001, Occupational Health and Safety, encourage employers to use the following hierarchy of hazard controls:
As you can see, the preferred control strategies first try to control hazards through elimination, substitution, or engineering. If the hazards can't be eliminated, replaced, or engineered, the hierarchy next attempts to control exposure to hazards through warnings, administrative methods and personal protective equipment. It's important to understand that:
The "big idea" behind this hierarchy is that the control methods at the top of the list are potentially more effective and protective than those at the bottom. Following the hierarchy of controls leads to the implementation of inherently safer workplace environments, where the risk of illness or injury has been substantially reduced.
Totally eliminating hazards, while most effective at reducing exposure to hazards, also tends to be the most difficult to implement in an existing process. This approach involves the initial design or redesign of tools, equipment, systems, production processes, and facilities in order to eliminate hazards associated with work.
If the machinery, equipment, or process is still at the design or development stage, eliminating hazards may be inexpensive and simple to implement. However, for an existing process, major changes be that can be very expensive. In the long term, even expensive changes that eliminate serious hazards may be cost effective.
Examples of elimination controls include:
Substitution also focuses on doing something with the hazard, itself. It is simply replacing hazardous materials, processes, operations, machinery, and equipment with those that are less hazardous to reduce the severity of exposure. If you can't eliminate the hazard, then your thought should be, "how can I substitute this hazard with something less hazardous?"
Replacing hazardous chemicals, materials, tools, equipment or machinery may be expensive, but not as expensive as the average direct and indirect costs of a lost work time injury. According to the National Safety Council, is $34,000 and over $1 million to close a fatality claim.
Engineering controls use Prevention through Design (PtD) methods to prevent injuries and illnesses by "designing out" the hazards and risks. This approach involves the design or redesign of tools, equipment, systems, work processes, and facilities in order to reduce or eliminate the hazards associated with work.
PtD considers what is needed to protect workers throughout the life cycle process, machinery or and/ or process is being designed. The life cycle starts with concept development, and includes design, construction or manufacturing, operations, maintenance, and eventual disposal of whatever is being designed, which could be a facility, a material, or a piece of equipment.
It's worth saying again, well-designed engineering controls are highly effective in protecting workers and will typically be independent of worker interactions to provide this high level of protection: no matter what workers do, they won't be exposed to hazards.
Examples of effective engineering controls include:
When considering engineering controls, you should think about the feasibility, costs, and ease of implementation of replacing or redesigning the equipment. OSHA expects your employer to consider these first three control strategies before employing administrative controls or personal protective equipment (PPE).
With the release of ANSI Z10-2012, "warnings" have been promoted to their own hierarchy level. Previously they were considered part of administrative controls. Warnings do not prevent exposure to a hazard, but they do provide a visual or audible indicator to warn people of potential danger.
Warnings can be either visual, audible, or both. They may also be tactile. Some examples of warnings are:
For instance, a door could have both a sign warning of a hazard as well as an alarm if opened. Warnings can be effective deterrents, but are not as effective as elimination, substitution, or engineering controls.
OSHA's 1910.145, Specifications for accident prevention signs and tags details the following types of signs:
One potential problem when using warnings is the misinterpretation of the warning itself. Does the symbol or text clearly explain what the hazard is to the public? For example, if a sign only contains a written warning, someone might read the sign but not know what the warning actually means. Or, if an alarm sounds, what does the alarm mean? These are challenges when using warnings and why they are not as effective as higher-level controls.
When exposure to the risk is not, or cannot, be minimized by other means, you should introduce administrative and work practice controls to reduce the risk.
Administrative controls address how the work is to be performed, and direct people to work in a safe manner. They help establish effective processes and procedures in the workplace that reduce risk of injury and illness.
Work practice controls. These controls also focus on the way workers do their jobs to reduce exposure to hazards. Work practice controls help to limit exposure by decreasing the following factors:
A few examples of administrative and work practice controls include:
Preventive Maintenance. The best way to prevent breakdowns or failures is to monitor and maintain your equipment regularly. Determine what hazards could occur if your equipment is not maintained properly and plan to detect failures before they occur.
Personal protective equipment is equipment worn to minimize exposure to hazards that cause serious workplace injuries and illnesses. These injuries and illnesses may result from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards. Personal protective equipment may include items such as gloves, safety glasses and shoes, earplugs or muffs, hard hats, respirators, or coveralls, vests and full body suits.
When engineering, work practice, and administrative controls are not feasible or do not provide sufficient protection, employers must provide personal protective equipment to their workers and ensure its proper use. PPE should be used in conjunction with, not instead of, the other hazard control strategies. A common mistake some managers and supervisors make is that they try to save a little money when purchasing PPE. Do not skimp on quality PPE: it can save a life.
Employers are also required to train each worker required to use personal protective equipment to know:
If PPE is to be used, a PPE program should be implemented. This program should address the hazards present; the selection, maintenance, and use of PPE; the training of employees; and monitoring of the program to ensure its ongoing effectiveness.
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Hierarchy of hazard control is a system used in industry 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. Credit: Pertrain Pty Limited (2:06)