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Industrial Hygiene: Chemicals, and Noise, and Mold, Oh My!

What is Noise?

As discussed in a previous Hearing Conservation article on the Workers’ Compensation Services website, noise is any sound that is excessively loud, unpleasant, unexpected, or undesired. It is one of the many occupational health exposures from which agencies must protect employees. For many, the intensity of noise in a particular area, due in part to the length of time spent in the area without protection as well as other environmental and physical factors, may go unnoticed. Employees working in high noise areas may be experiencing occupational (work-related) hearing loss, sociacusis (hearing loss resulting from non-work-related exposures), or presbycusis (hearing loss resulting from the natural aging process) as a result of current or previous exposures or conditions of 85 decibels (dBA) or more. These employees may discover a shift in their hearing during required annual hearing tests, an indication of further hearing loss.

Hazards of Damaging Noise Exposures

High noise levels may not only prove hazardous to employees working in the immediate area but to other employees and equipment near the area. It may become increasingly difficult for an employee to concentrate, potentially causing carelessness with processes and procedures. Employees battling hearing loss may experience fatigue from restless nights which can translate to an increase in workplace injuries. Verbal and mechanical warnings may become more difficult to hear. An otherwise able-bodied employee may fail to respond appropriately, possibly putting themselves and others, including rescue/emergency personnel, in danger. Extreme noise exposures may also adversely affect the regulation of bodily functions, including blood pressure, muscle control, and hormone secretions.

Preventing Occupational Noise Exposures

To prevent employee exposures to potentially damaging occupational noise, the agency should conduct a noise hazard assessment to evaluate the work environment and identify potentially high noise tasks and areas. Distance from the source of the noise and the amount of time an employee is exposed are important factors to consider during the assessment.

Next, use a sound level meter or noise dosimeter to confirm the actual noise levels. If the agency does not own or have immediate access to noise monitoring equipment, it can be purchased or rented from a local or national vendor that specializes in environmental testing. Make sure measurements taken are on the A-scale. The A-scale is a slow response scale, which refers to the speed of the measuring needle as the monitoring is being conducted.

After noise levels are identified, determine if the operation can be re-engineered to prevent or reduce employee exposure. Engineering controls are the most effective means of controlling worker exposure because they are not affected by employee behavior. Some examples of engineering controls include:

  • installing sound dampening panels/curtains;
  • placing the noisy equipment behind an enclosure;
  • placing the noisy tool/equipment outside;
  • installing mufflers on the equipment;
  • securing equipment components that may be causing or contributing to the high noise.

If the hazard cannot be engineered out, the agency should try to implement administrative controls. Administrative controls are the policies and procedures implemented to protect employees from the hazard. Examples of administrative controls include job rotation, limiting the time an employee is exposed to the high noise, developing a low noise-producing equipment purchasing standard, written safety policies, and safe work rules.

Protecting Agency Employees

If other means of noise control are unsuccessful, the agency should consider providing personal protective equipment (PPE) in conjunction with the appropriate work practice controls. A variety of PPE should be made available to employees to ensure the appropriate level of protection and comfort. If PPE is not comfortable, an employee will most likely not use it or will use it inappropriately.

When choosing to provide PPE for employees, industry-appropriate research should be conducted to determine the best PPE solution for the employee exposure. The agency should consider:

  1. Pre-molded Earplugs
    • Silicone, plastic, rubber
    • Reusable
  2. Canal Cap Earplugs
    • Silicon, plastic, rubber
    • Band joins plugs
    • Can be worn over head, under chin, behind neck
    • Can be carried around neck when not in use
  3. Foam Earplugs
    • Foam, rubber
    • One size fits most
    • Expands to fit ear canal
  4. Ear muffs
    • Cover outer ear
    • Can be worn with plugs
    • May include radio communication components
    • Not to be substituted with stereo headphones

Proper PPE selection also includes selecting the appropriate noise reduction rating (NRR) for the work environment. The number listed on the packaging indicates the noise reduction value of the selected hearing protection. The NRR should not be directly subtracted from the noise monitoring results. Subtract 7 from the NRR, and then subtract that result from the sound level/noise dosimeter reading. The resulting number is the noise level exposure for the employee while wearing hearing protection. This number should be well below 85 dBA.

Once it has been determined that the agency cannot control a high noise hazard that is greater than 85 dBA over an 8-hour period (the time-weighted average) using engineering controls, a hearing conservation program must be developed and implemented in accordance with the Occupational Safety and Health Administration/Virginia Occupational Safety and Health (OSHA/VOSH) 29CFR 1910.95, Occupational Noise Exposure. Noise monitoring should be repeated if there are any changes in the environment or work processes. Protected employees are informed employees. According to the OSHA/VOSH standard, employers must notify any employees that are exposed to noise levels of 85 dBA or greater for more than eight hours based on the monitoring results.

Finally, any employee exposed to areas 85 dBA or greater for an eight-hour period must have audiometric testing conducted within six months of the high noise exposure and at least annually thereafter. The audiometric testing is used to determine if there has been a decrease in the employee’s hearing since being exposed to high noise levels in the work environment. Local resources for audiometric testing include occupational testing centers, hospitals, and physicians specializing in occupational services.

Employers should take a proactive approach to protecting employees from occupational hearing loss by identifying and evaluating noise hazards, implementing engineering and administrative controls, and providing the appropriate level of PPE. The damaging effects of occupational hearing loss can be felt physically, emotionally, and socially for years to come. Remember, a healthy employee is a productive employee.


Occupational Safety and Health Administration (n.d). 29 CFR 1910.95-Occupational Noise Exposures. Retrieved September 15, 2006 from,

Occupational Safety and Health Administration (4/04/05). Noise and Hearing Conservation: Measuring Exposure. Retrieved 9/21/06 from,

Occupational Safety and Health Administration (n.d.). OSHA Technical Manual, Noise and Hearing Conservation, Appendix I:C Effects of Excessive Exposure. Retrieved September 21, 2006 from,

Virginia Workers’ Compensation Services (9/2006). Hearing Conservation. Retrieved September 14, 2006 from,

Noise Hazard Assessment Worksheet

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