OSHA Directive STD 0.2 Identification of General Industry Safety and Health Standards (29 CFR 1910) Applicable to Shipyard Work specifically states that employers in the shipbuilding industry that are covered by the 29 CFR Part 1915 Standards are required to comply with a number of 29 CFR Part 1910 standards, including the 1910.95 requirements for occupational noise.

The STS computation is to be made in accordance with the Occupational Noise Exposure Standard 1910.95. As OSHA stated in the preamble to the July 1, 2002 rulemaking, the Section 1904.10 regulation "[u]ses existing measurements employers are already using to comply with the OSHA noise standard, resulting in less paperwork burden for employers covered by both rules" (67 FR 44040). Under 1910.95, the employee's current audiogram is compared to the employee's baseline audiogram, which may be the original audiogram taken when the employee was first placed in a hearing conservation program, or the revised baseline audiogram allowed by the Occupational Noise Exposure standard. Paragraph 1910.95(g)(9) of the noise rule states:

(9) Revised baseline. An annual audiogram may be substituted for the baseline audiogram when, in the judgment of the audiologist, otolaryngologist, or physician who is evaluating the audiogram:

(i) The standard threshold shift revealed by the audiogram is persistent, or

(ii) The hearing threshold shown in the annual audiogram indicates significant improvement over the baseline audiogram.

OSHA's former recording criteria required the employer to track separate baselines for recording and hearing conservation purposes. However, the new Part 1904 hearing loss recording system relies on the existing 1910.95 calculations, and separate baselines will no longer be required. In short, under the new Part 1904, a recordable hearing loss case occurs when an employee experiences an STS (as defined in 29 CFR 1910.95), the STS is work-related, and the employee's aggregate hearing loss exceeds 25dB from audio metric zero.

As noted in the July 1, 2002 rulemaking, the new criteria will capture more hearing loss cases. Employers will experience an increase in recorded hearing loss cases in 2003 and future years. Caution must be used when comparing the 2003 and future data to prior years, when the 25 dB criteria for recordkeeping was used. OSHA recognizes this increase, and will take the changes in the recordkeeping rule into account when evaluating an employer's injury and illness experience.