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159 Hearing Protection: Basic
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Temporary and Permanent Hearing Loss

While a single exposure to loud noise can damage your hair cells, it probably won't destroy them.

Repeated exposures to loud noise can damage hair cells to the point that they won't recover.

You may experience ringing in your ears and some sounds may be muffled, but your hair cells will recover and so will your hearing. This is called a temporary threshold shift.

Repeated exposures to loud noise can damage hair cells to the point that they won't recover. Because the damage is permanent, the result is called a permanent threshold shift. No treatment will restore it. When you destroy hair cells, you destroy hearing.

Exposure to Chemicals

No longer is noise considered to be the only source of hearing loss associated with work. Exposure to chemicals, like aromatic solvents, and metals, such as lead, arsenic, and mercury, can result in hearing loss.

Combined exposures to noise and chemicals can cause more hearing loss than exposure to either agent alone. Vibration and extreme heat are also potentially harmful to hearing when combined with noise.

Knowledge Check Choose the best answer for the question.

1-4. Permanent hearing loss is usually the result of _____.