Hierarchy of Controls For Mercury

Hierarchy of Controls

The hierarchy of controls should be applied to ensure you use the most effective control method. The hierarchy of controls establishes the following control categories in order of preference: elimination, substitution, engineering, administrative, and personal protective equipment (PPE). Controlling hazards within a workplace help prevent accidents or injuries. Controls, such as elimination, substitution, and engineering, are most effective because they do not rely on human behavior. Administrative and PPE controls are least effective since they may not eliminate the hazard and rely on human behavior and performance. A cost-benefit analysis can help guide decision-making when implementing the hierarchy of controls.

Elimination and Substitution

Whenever possible, exposure to potential hazards should be eliminated or reduced by substituting with less hazardous materials. Choosing mercury-free equipment or equipment made with less toxic substances minimizes the potential for worker exposure. For example, replacing mercury thermometers and sphygmomanometers with mercury-free devices eliminate the hazard.

When in the development phase of a new process, implementing elimination or substitution controls may be inexpensive and easy to implement. It may be more difficult and expensive to implement elimination or substitution controls for existing operations.

Engineering Controls

When elimination or substitution is not possible, engineering controls should be applied. Engineering controls work by physically preventing worker exposure to the hazard. Engineering controls are considered a more effective control method as compared to administrative controls or PPE because they do not rely on worker compliance.

Well-designed engineering controls, such as a sealed container, can be highly effective in protecting workers from mercury. Engineering controls should be independent of worker behavior and interactions.

Potential engineering controls include:

Use fume hoods to prevent exposure to mercury vapors
Use a process enclosure to prevent exposure
Control airflow in the work area with adequately designed ventilation systems

Health Effects & Occupational Exposure to Mercury

Administrative Work Practice Controls

Administrative controls are policies and procedures established by management to reduce the risk of exposure to a hazard, such as mercury. Administrative controls include implementing work practices, management policies, and training programs to reduce worker risk.

Administrative controls used to protect workers from exposure to mercury include:

initial and annual training
evaluation and maintenance programs

Use a variety of work practice controls to protect healthcare workers from accidental mercury spills.

Use mercury spill kits to help clean up small spills of 25ml or less. Kits should contain gloves, protective glasses, mercury absorbing powder, mercury sponges, and a disposal bag.
Put in place procedures to isolate the contaminated area.
- Be aware that mercury can unknowingly be carried home on clothing, skin, or hair.

Be on the look-out for mercury, recognizing that it may be present in various instruments and equipment.
Use a Mercury Vapor Analyzer to verify that the area is safe to reenter.
Make sure that spills are cleaned up promptly and safely by workers or a team trained in proper procedures.

Do not allow workers who are not trained in proper procedures to attempt to clean up spills.

Personal Protective Equipment

The last line of defense against exposure to workplace hazards is personal protective equipment (PPE). Employers are required to provide appropriate PPE when employees are handling hazardous chemicals, such as mercury [29 CFR 1910.132]. PPE is the least effective control method because it relies on employee behaviors and performance to prevent exposure.

Examples of PPE include:

coveralls
booties
gloves
face shields
safety goggles
respirators

Hierarchy of Controls For Mercury