It’s not always painful. Nor does it occur overnight. In fact, you may not even know when it’s occurring. Occupational hearing loss, primarily caused by high noise exposure, is the most common U.S. work-related illness in manufacturing, according to NIOSH.  

While hearing loss is irreversible, it doesn’t have to be inevitable for those workers who find themselves regularly working in noisy environments.

In this article, we’ll examine hearing loss and leading causes, an overview of the history of hearing protection, and seven elements that workplaces should consider when implementing a Hearing Conservation Program (HCP) or Hearing Loss Prevention Program (HLP).

Leading causes

Shaped like a snail, the inner ear or cochlea contains thousands of tiny sensory cells called hair cells, which convert sound waves into electronic signals that are dispatched to the brain via the hearing nerve. The brain then deciphers those signals and tells us what we’re hearing.

Experiences such as exposure to loud noises over time, as well as aging, may damage or kill inner ear hair cells. Common symptoms of hearing loss include difficulty understanding softer or higher pitched voices or hearing conversations where there is noise in the background, such as a busy restaurant. Sadly, noise-induced hearing loss is permanent and there is no cure.

Despite our nation’s long history of requiring hearing protection and hearing conservation programs for people who work among loud noises, NIOSH reports that hearing loss rates remain high in many industries, especially mining, construction and manufacturing.

The following are seven basic elements for HCPs, which are based on both OSHA requirements and best practices recommendations from NIOSH. They are Measure, Control, Protect, Check, Train, Record and Evaluate.


OSHA requires that all employees whose noise exposure equals or exceeds an A-weighted, eight-hour time-weighted average (TWA) of 85 decibels must be included in a HCP. For comparison, busy city traffic is also rated at approximately 85 decibels.

Measuring noise exposure on the job as part of an HCP can be done with either a sound level meter or dosimeter or both. Measurements should be taken at different times to help determine the different noise levels experienced throughout a workday. Employee movement and sound instrument calibration and maintenance should also be considered in a comprehensive measurement program.

Sound measurement apps on mobile phones may be useful for raising awareness of noise problems in the workplace but only calibrated “Type 2” (or better) instruments can be used for compliance with occupational health regulations.


In some cases, employers and occupational safety professionals can reduce hazardous noise by addressing the source of the workplace noise. NIOSH suggests:

  • Purchasing and upgrading to low-noise tools and machinery
  • Regular maintenance of tools and equipment
  • Reducing vibration when feasible
  • Isolating noise in a room or enclosure or placing a barrier, such as a sound wall or window, between the noise source and the employee.


Even with the best noise-damping measures taken, workplace noise is sometimes inevitable. In this case, it’s time to provide hearing protection devices.

No one earplug fits all people. Today’s hearing protection addresses a variety of workplaces environments and conditions, including different decibels levels, specific industries, as well as different communication requirements.

Accessibility is another common program. Are earplug dispensers available in just some or in many locations throughout a worksite? Other important considerations include comfort, fit and compatibility with other personal protection equipment. Individual fit testing of earplugs and earmuffs should be a part of an HCP to ensure each worker has the right equipment with proper fit.

To help ensure employees are getting the protection they need, workplace safety managers should know the Personal Attenuation Rating (PAR) of every employee. A PAR can be assessed with a hearing protection fit testing system.

Some of the following questions are among the types of issues you should consider when selecting a system for validating the fit of hearing protectors:

  • Does the system address every employee’s unique needs and challenges?
  • Is it science-based, providing objective and quantitative testing?
  • Can it test a variety of devices?
  • Does it quickly test multiple frequencies?
  • And, if there are multiple employees, does it offer quick, accurate testing per employee?


It’s important to routinely use standardized measurement procedures to check each workers’ hearing to track any changes. The audiometric equipment must be calibrated and checked for wear and tear as well. Changes in hearing, as defined by the regulatory agencies, require intervention. If the current hearing protection product being used isn’t meeting the workers’ needs, a change needs to be made.


Because noise-induced hearing loss usually happens gradually and the symptoms are not always apparent, it is vital to educate employees on the effects of exposure to loud noise and train them to properly use hearing protection.

Worker training and motivation programs can improve the success of your hearing loss prevention efforts.

Once employees are tested and provided adequate hearing protection, training is a necessary next step. While large-group training is efficient, there is good evidence that one-on-one training on proper use of hearing protectors, including individual fit testing to measure how well the devices fit each person, can lead to a significant improvement in PAR.


OSHA requires that employers keep noise exposure measurement records for at least two years and to maintain records of audiometric test results the entire period an affected worker is employed. Employers are also required to record work-related hearing loss when hearing tests show a marked decrease in overall hearing.

Other records such as worker training, fit testing, equipment calibration and technician certification should also be kept for an extended time to document all the employer’s efforts to prevent noise-induced hearing loss.


As with any protection program, it’s good to do an assessment from time to time. Has the workplace environment changed with the introduction of new equipment? Are employees regularly wearing hearing protection during site checks? And, when asked, do they know how to wear it properly?

Employers must also perform regular hearing tests to determine whether an HCP is effective and to note whether an employee experiences a marked decrease in hearing, as shown in the “testing” section.