Occupational hearing guidelines allow damage, not prevention of loss.

Evidence

The occupational hearing conservation guidelines 249. are important for those who work in noisy occupations, 5 days a week for a working lifetime. Applying them to occasional exposures is incorrect but often done. It is assumed that these guides prevent hearing loss. That is not the case. They permit hearing loss to occur, aiming only to conserve enough at the end of a working life to permit carrying on a generally intelligible conversation at a distance of 1 m in the quiet. Appreciating the subtleties of live or reproduced sounds would be a pleasure long gone. To workplace noise exposures must be added non-occupational noise exposures: rock concerts, shooting, motorcycles, lawn mowers, power tools, automobile air bag deployment, etc. all of which contribute to the lifelong accumulation of hearing damage. It is estimated that sounds above about 75 dB can contribute, slowly but surely, to the accumulated lifetime hearing loss. — Toole, Floyd E, Sound reproduction- the acoustics and…, 892

Categorization

• XREF: Connects to the reader’s established interest in noise and hearing damage from titles like ‘One Square Inch of Silence’ and ‘The Soundscape.’
• SEED: Angle: the 75 dB threshold means ordinary life itself is a slow hearing-loss mechanism, so ‘normal’ hearing is really ‘degraded’ hearing.