As many as 16 million employees are exposed to high noise levels at work.  Sound enters the outer part of the ear which is made of cartilage covered by skin.  Sound waves travel down the ear canal.  They cause the eardrum (which is located at the entrance of the middle ear) to vibrate.  The vibrations pass on through the middle ear by causing the small bones to vibrate.  The vibrations move fluid in the cochlea of the inner ear.  The cochlea is the main organ of hearing in the body and contains about 20,000 hair-like cells.  The moving fluid moves or bends these cells which change vibrations into nerve impulses.  The nerve impulses are carried to the brain by the auditory nerve.  This nerve sends the sound signal to the hearing center of the brain.

Noise is unwanted or unpleasant sound.  Loud noise causes the hair cells to bend or go flat.  Usually these cells rise back up if the noise goes away.  But constant noise or a sudden loud sound can be so strong that the cells don’t recuperate.  Exposure to long-term noise may result in tinnitus.  This is a roaring, ringing, or whistling sensation in the ear that comes and goes or is constant.

To Protect Your Hearing:

·                     Maintain machinery to reduce noise levels.

·                     Know when hearing protection is required and wear hearing protection in loud-noise activities.

·                     Wear assigned hearing protectors.

·                     Don’t wear poor fitting or damaged hearing protectors.

·                     Make sure hands are clean before inserting or putting on hearing protectors.

·                     Don’t wear home made hearing protection.

Select the proper ear protection to protect your hearing.  Types of hearing protection include:

1.     Earplugs.  These seal the ear canal and may come in standard sizes or individually molded varieties.  Some are disposable while others are reusable.

2.   Canal Caps.  These are soft pads on a headband similar to headphones.  They seal the entrance to the ear canal.

3.   Earmuffs.  Similar to headphones and provide the greatest protection.

Approximately 30 million workers are exposed to hazardous noise on the job. While we would prefer to eliminate noise through engineering controls or reduce exposure to noise through administrative controls, hearing protectors are critical when noise is unavoidable. 

Hearing protectors only work if they fit your ears and you wear them properly.  An earplug that doesn't quite fill your ear canal or an earmuff with a small crack in the padding will let lots of noise into the ears through any gaps, even tiny ones.

To help you get the most from your hearing protectors, researchers at the National Institute for Occupational Safety and Health's (NIOSH) Pittsburgh Research Laboratory developed QuickFitWeb, an online tool to check your hearing protection in a minute or less.

Poor Fit = Poor Protection

Studies of hearing protector users have shown repeatedly that average protection values in the real world are much lower than the labeled Noise Reduction Ratings (NRR) determined in laboratories with trained and motivated subjects. Even worse, many hearing protector users get virtually no protection at all because of poor fit. It's hard to tell if your hearing protectors are working well just by looking at them. A more accurate approach is to check how much they block or "attenuate" noise. Hearing protectors vary in their attenuation characteristics, with most providing a maximum of 20 to 35 decibels of noise reduction when worn correctly. Any hearing protector that's suitable for use in noisy settings will attenuate noise by at least 15 decibels.

How QuickFitWeb Checks Hearing Protectors

The NIOSH QuickFitWeb helps you determine if your hearing protection is giving you at least 15 decibels of attenuation by comparing two "threshold" tests—one without hearing protection and one with the devices on or in your ears.

Click here for the complete CDC article and to try the QuickFitWeb