Hearing loss is usually insidious, occurring gradually over a long period of time. It can be temporary or permanent based on the type of hearing loss. Hearing loss happens so gradually the person affected usually does not notice it until conversations become difficult, especially in situations where background noise is occurring. It can also happen instantaneously such as during an incident like an explosion or sharp blow to the head.
Causes of Hearing Loss
Typical industrial hearing loss can be caused by long term exposure to loud noises and sometimes exacerbated by a combination of loud noises and exposure to certain chemicals on the job such as toluene, xylene, n-hexane, organic lead, mercury and others [see Occupational Ototoxins (Ear Poisons) and Hearing Loss for more information]. While not much research has been conducted on the combination, many Industrial Hygienists and Industrial Audiologists have arrived at this conclusion.
Noise induced hearing loss can also be caused by exposures in settings other than industrial or work related experiences. For instance, loud music at concert settings has been found to be as high as 120 decibels which exceeds allowable OSHA/WISHA noise standards. Off the job noise can also be contributed to by wood cutting with power saws, which typically can exceed 105 decibels. Because of this, many companies encourage their employees to take ear plugs home for use.