The Center for Disease Control (CDC) reports that around 22 million workers experience potentially damaging occupational noise every year. About 33% of them have had a history of noise-related damage, and 16% suffered from quantifiable hearing impairment.
Noise exposure has been acknowledged as a work hazard for centuries. Thus, several institutions, like the Occupational Safety and Health Administration (OSHA), have implemented programs and standards to protect workers from the detrimental effects of occupational noise exposure.
What is Noise?
Sound refers to the vibrations that the human ears detect. When a sound is unwanted and unnecessary, we call it a “noise.” Exposure to high sound level, noise level, and vibrations may harm individuals, especially when the exposure is long-term.
OSHA sets legal limits on occupational noise exposure through OSHA 29CFR 1910.95 Occupational Noise Exposure standard. According to the CFR 1910.95, OSHA’s permissible noise exposure limit (PEL) for all workers is 90 dbA for an 8 hour time weighted day. OSHA sets the limits based on the employee’s hour time weighted average (TWA) over an 8-hour day period.
Since the OSHA standard applies a 5 dBA exchange rate, when the noise level increases by 5 dBA, the amount of time an individual can be exposed to a specific noise level is cut in half. Following this standard is critical in protecting workers from the detrimental effects of excessive occupational noise exposure.
Noise Exposure Health Effects
Regular exposure to excessive occupational noise may lead to permanent noise induced hearing loss that either surgery or a hearing aid cannot fix. Even short-term exposure may cause tinnitus and change in hearing.
Repeated short-term noise exposure can also lead to permanent tinnitus or permanent hearing loss. Other detrimental health effects of excessive occupational noise exposure include hyperacusis or the reduced tolerance to sound and balance difficulties.
Aside from auditory and physical damage, occupational noise exposure can also create psychological stress, lessen productivity, and interrupt attention. This workplace hazard can also hinder effective communication and cause workplace accidents due to difficulties communicating warning signals.
The damaging health effects of occupational noise exposure show how important it is to have programs and follow standards regarding noise exposure. Fortunately, OSHA established its own noise standard that employers need to implement.
Daily Noise Exposure Allowance
Aligned with the CFR 1910.95 standard, the following chart shows the permissible noise exposures; exceeding these limits may cause adverse health effects on individuals. The higher the noise level, the lower the exposure duration is allowed to avoid significant health risks.
The table shows that exposure to 90 dBA for 8-hours a day is permissible — the same with exposure to 115 dBA for fifteen minutes or less. The CFR 1910.95 standard aims to inform how much noise level is considered safe relative to its exposure time.
|Noise Level||Exposure Time|
|90 decibels||8 hrs|
|92 decibels||6 hrs|
|95 decibels||4 hrs|
|97 decibels||3 hrs|
|100 decibels||2 hrs|
|102 decibels||1 hr 30 minutes|
|105 decibels||1 hr|
|110 decibels||30 minutes|
|115 decibels||15 minutes and less|
Hearing Conservation Program
OSHA CFR 1910.95(c) requires employers to establish a hearing conservation program when noise exposure reaches or exceeds 90 decibels averaged over eight working hours. The purpose of this program is to protect workers from high levels of noise and its damaging effects.
Through a hearing conservation program, employers are mandated to conduct free hearing exams, provide hearing protection devices, and offer evaluations on the efficiency of their hearing protective equipment.
Key Elements of an Effective Hearing Conservation Program
OSHA identified that an effective hearing conservation program has the following key elements:
- Employee noise exposure monitoring
- Application of work practice, engineering, and administrative controls for high levels of noise
- Provision of an individually-made hearing protector device with sufficient noise reduction rating for every overexposed worker
- Noise hazards and protection measures training and education
- Baseline and annual audiometry
- Provision of procedures to prevent further occupational hearing loss by an employee
OSHA suggests that workplaces with high levels of occupational noise should include as many elements from this list as possible for the protection of everyone.
Evaluation of Occupational Noise
Occupational noise levels are evaluated through sound-measuring instruments such as sound level meters, noise dosimeters, and octave band analyzers. Employers will notify their workers when their noise exposure reaches 85 decibels within 8 hours.
The monitoring process shall be adjusted when sound level and hour time weighted average (TWA) change. Employers are also required to monitor the sufficiency of the employees’ hearing protection devices.
Each employee will be tested for their respective baseline audiograms. A certified audiologist will conduct this within the first six months of the employees’ first exposure to occupational noise.
The baseline audiogram will be compared to subsequent audiograms. Then, the data will be assessed for threshold shifts, after which adjustments to the hearing protective devices will be provided.
Nevertheless, OSHA suggested that the following are some signs that there is a noise problem in the workplace:
- Hearing humming or ringing noises even after you have left your workplace
- Needing to shout just to be heard by a coworker
- Having temporary hearing loss after you leave work
Workplace Noise Reduction
According to the National Institute for Occupational Safety and Health (NIOSH), occupational safety and health professionals apply the hierarchy of control to identify how to execute practical and efficient noise reduction controls.
In this approach, control actions are grouped based on their effectiveness in lowering or eliminating noise hazards. The first line of action is usually to remove the source of damaging noise. If removal is not an option, then substituting the source with a quieter version may be a suitable alternative.
If removal and substitution are not possible, then engineering controls are required to be installed to ensure that occupational noise is at a safer level. Engineering controls may include redesigning equipment to remove noise sources and creating barriers to protect workers from the noise.
Employers should implement administrative controls if noise reduction is not possible through removal, substitution, and engineering controls. These controls include changing work schedules to avoid occupational noise exposure.
Lastly, if all these controls do not work, wearing personal protective equipment (PPE) is the last option. The PPE includes hearing protectors or hearing protection devices like earplugs.
Although the hearing protection equipment is usually less adequate, it can be combined with other controls to reduce employees’ excessive noise exposure.
Hearing Protection Devices
If removal, substitution, and engineering controls did not work, wearing hearing protection devices would be the last resort. These devices are used based on the occupational noise levels and the overall environment:
- Expandable foam plugs - made from formable materials that expand and conform to ear canal shape
- Reusable plugs - pre-molded plugs made of silicone, rubber, or plastic that are often “one-size-fits-all”
- Canal caps - either pre-molded or formable; made of a metal band or flexible plastic, usually with a headband worn over the head
- Earmuffs - cover the entire outer ear to block out noises
- Miscellaneous devices - include hybrid models made of high-tech materials equipped with communication lines
As visual tools, putting up signages will raise awareness among workers of possibly damaging high levels of noise. Signages and warning signs will help remind workers to wear hearing protection devices.
Although some neglect the convincing power of signages, these should be used and enforced to ensure employees’ safety.
Organizations may opt to keep records of employees’ measurements and assessments regarding occupational noise exposure. Nevertheless, it is much more necessary to use audiometric test records to measure the health of employees’ hearing ability. Recordkeeping is critical in monitoring employees’ safety against occupational noise exposure.
The hearing conservation program must be supplemented with an annual training course to serve as a refresher for current and new employees.
The training includes a detailed explanation of the health risks associated with high levels of occupational noise exposure, the functions of different noise protective devices, the proper usage of and care for these devices, and the various audiometric testing methods available.
Considering the CDC’s statistics and the detrimental health effects of excessive occupational noise exposure, businesses should be more aggressive and consistent in implementing the OSHA standard, as well as their hearing conservation program. Productivity increases and absenteeism decreases when employees are protected from excessive noise.
OSHA also imposes huge fines on companies that neglect the implementation of an effective hearing conservation program. After all, businesses benefit the most when they strictly comply with the OSHA standard and their hearing conservation program.