ABSTRACT
Noise has been a universal problem from the time man first put hammer to stone. Our lives have not gotten any quieter. On-the-job hearing loss due to noise is the most common form of occupational injury in the United States. Estimates by the National Institute for Occupational Safety and Health (NIOSH) in the early 1980s estimated that about four million workers were exposed to noise in excess of 85 dBA (NIOSH, 1998). NIOSH calculates that a lifetime exposure to noise in excess of 85 dBA will cause an excess risk of 15% of those workers suffering a disabling hearing loss. With exposure to 90 dBA over a working lifetime, the estimated risk almost doubles to 29%. Current thinking is that every ear is vulnerable to noise — given enough acoustic energy at the right frequency for enough time.
