What were the reasons for choosing the 80 dBA and 90 dBA threshold levels?
Reply: The lower 80 dBA threshold was chosen to facilitate the proper identification of employees who need to be included in the hearing conservation program. This limit is consistent with accepted measuring techniques for dosimeters. According to ANSI, the lower threshold of a dosimeter should be 5 dBA below the level for which the measurements are being taken. For hearing conservation, the level was set at 85 dBA, or the equivalent noise dose of 50%, because the evidence suggests that a large percentage of the population whose exposures exceed this level over a working lifetime will incur noise-induced hearing loss. This level is also consistent with other OSHA health standards in setting an action level at half the PEL. Please be aware that during the revision period, the period during which OSHA conducted rulemaking to establish the new provisions of the Hearing Conservation Amendment, only that section, 1910.95(b)(3), was opened for revision. Therefore, because the 90 dBA threshol