October is National Protect Your Hearing Month, an annual public health campaign spearheaded by numerous federal agencies to raise awareness about noise induced hearing loss.

According to the Centers for Disease Control and Prevention (CDC), 22 million workers face dangerous levels of noise exposure on the job each year, and millions more adults never or rarely wear hearing protection at entertainment venues or loud sporting events.

Hearing loss can be irreversible. It is important to take precautions before it is too late.

How Does Hearing Loss Happen?

Hearing loss occurs when there is a problem with the ear, the nerves connected to the ear, or the part of the brain that controls a person’s ability to hear. When someone experiences hearing loss, it not only affects their ability to hear or understand speech but other sounds as well.

When a person sustains short-term or permanent hearing loss, the following factors are usually at play:

• Damaged hair cells in the ear. On average, a person is born with 16,000 hair cells in their cochlea (inner ear). Hearing tests generally cannot detect an issue until 30 percent to 50 percent of a person’s hair cells have been damaged or destroyed from hazardous levels of noise exposure.
• Damage to the nerves in the ears. Similar to how noise can damage or destroy the hairs in the cochlea, it can also damage the auditory nerve that carries a signal from the ear to the brain.
• Damage to the cells and membranes in the cochlea, which typically results from a single loud noise or repeated exposure to high noise levels.

The Mayo Clinic reports that some of the most common signs and symptoms of hearing loss include difficulty understanding words, especially against background noise or in a crowd; muffling of speech or other sounds; trouble hearing consonants; needing to turn up the volume of a television or radio; frequently asking others to speak more slowly, clearly, or loudly; withdrawal from conversations, and avoidance of some social settings. If you are experiencing trouble hearing, it is a good idea to set up an appointment with your healthcare provider.

Preventing Hearing Loss at Work

While almost all cases of hearing loss that result from high levels of occupational noise exposure are preventable, every year millions of workers – like those who go without proper training, supervision, and personal protective equipment – sustain irreversible damage to their hearing.

To reduce noise-related hazards, the Occupational Safety and Health Administration (OSHA) requires that employers take certain steps to protect workers, including:

• Maintain and lubricate machinery and equipment to avoid excessive noise during start up and operation.
• Choose low-noise tools and machinery.
• Enclose or isolate noise sources.
• Place a barrier between the noise source and employee, like curtains or sound walls.
• Provide workers with a quiet area so they can gain relief from hazardous noise sources.
• Operate especially noisy machinery when fewer people are in close proximity.
• Limit the amount of time workers spend around known noise sources.

Monthly Toolbox Talk

Most of us go through life taking our senses for granted. Touching, tasting, smelling, seeing and hearing is something we do automatically. When something goes wrong with any of our senses, we expect that it can be fixed through medical science.

Unfortunately, medicine offers only moderate improvement for people with hearing loss. Hearing loss cannot be restored for most people.

Exposure to normal noise levels does not cause hearing loss. Hearing loss occurs because of overexposure to high noise levels. Noise is measured in units called “decibels” (dB). The higher the decibel scale, the louder the noise. Here are a few examples of noise levels.

• 20 dB: Soft whisper
• 30 dB: Leaves rustling, very soft music
• 60 dB: Normal speech, background music
• 85 dB: Heavy machinery with soundproof cab
• 90 dB: Lawnmower, shop tools
• 100 dB: Heavy machinery without soundproof cab, motorcycles
• 115 dB: Loud music, sand blasting
• 140 dB: Jet engine, shotgun

In the workplace, hearing protection must be used to reduce noise exposure for anyone who is generally exposed to 90 dB or more over the course of the workday. Hearing protection may be used at lower levels, particularly by people who are very close to the 90 dB exposure level. Sounds about 120 dB can cause hearing damage after brief exposure and should be avoided unless protection is worn.

Most hearing protection is given a Noise Reduction Rating (NRR) of between 20 and 30 dB. However, you should deduct 7 dB from the earplug NRR to more accurately determine the protection offered. For example, if a jackhammer’s noise exposure level is 102 dB and we use earplugs with an NRR of 29, consider the actual NRR to be 22 dB. This would reduce noise exposure from 102 to 80 dB, which is below the OSHA permissible exposure limit.

Keep in mind that not every type of hearing protection is not good for every type of noise. Disposable foam ear plug may be fine for some noise exposure, while earmuff-style protection may be suitable for another.

Remember, equipment operators are not the only ones who may need protection; people who work nearby may also be exposed. If you work in a noisy area, even if you are not the one making the noise, be aware of the hazard and use protection.