OSHA Recordkeeping Handbook - denix

occurs, and where hearing loss can have a significantimpact on workers’ lives outside of verbal communication.Using these frequencies reduces the burdenon employers that would be created by requiringseparate calculations of audiometric results, and, as...stated “(w)ith regard to the early effects of noiseexposure, it seems reasonable to extend the definitionacross the standard shift frequencies 2000, 3000,and 4000 Hz” (Ex. 3-62).Baseline Reference and Revision of Baseline…The two-part test for recording that is being adoptedin the final rule uses the baseline audiogram asthe reference point for determining whether or notthe employee has had a change in hearing whileemployed by his or her current employer, and thenuses audiometric zero as the reference point fordetermining the overall hearing ability of the affectedemployee. OSHA agrees that the employee’s baselineaudiogram is a superior reference point for measuringa change of hearing, a Standard Threshold Shift.Using the baseline audiogram taken upon employmentreduces the effect of any prior hearing loss theemployee have experienced, whether it is non-occupationalhearing loss or occupational hearing losscaused by previous employment. Therefore, the finalrule uses the employee’s original baseline audiogramas the reference for the STS component of an initialhearing loss cases, and uses the revised baselineaudiogram from that initial case as the reference forfuture cases.The 25-dB total hearing level component of anOSHA recordable hearing loss uses a reference ofaudiometric zero. This portion of the recording criteriais used to assure that the employee’s total hearinglevel is beyond the normal range of hearing, so itdoes not exclude hearing loss due to non-work causes,prior employment, or any other cause. The measurementsimply reflects the employee’s current hearingability as reflected in the most recent audiogram.This comparison to audiometric zero is a simple matter,because audiometers are designed to provideresults that are referenced to audiometric zero. Thehearing level at each frequency is oftentimes printedby the equipment, so there is rarely a need to performmanual calculations….[67 FR 77169, Dec.17, 2002]D. Other Hearing Loss Issues…The second issue involves the computation of aStandard Threshold Shift (STS), which is one part ofthe two-part recording criteria recently published (67FR 44037-44048). (The case must also reflect a 25 dBOSHA RECORDKEEPINGhearing level compared to audiometric zero.) TheSTS computation is to be made in accordance withthe Occupational Noise Exposure Standard 1910.95.As OSHA stated in the preamble to the July 1, 2002rulemaking, the Section 1904.10 regulation “[u]sesexisting measurements employers are already usingto comply with the OSHA noise standard, resulting inless paperwork burden for employers covered byboth rules” (67 FR 44040). Under 1910.95, theemployee’s current audiogram is compared to theemployee’s baseline audiogram, which may be theoriginal audiogram taken when the employee wasfirst placed in a hearing conservation program, or therevised baseline audiogram allowed by theOccupational Noise Exposure standard. Paragraph1910.95(g)(9) of the noise rule states:(9) Revised baseline. An annual audiogram maybe substituted for the baseline audiogram when, inthe judgment of the audiologist, otolaryngologist, orphysician who is evaluating the audiogram:(i) The standard threshold shift revealed by theaudiogram is persistent, or(ii) The hearing threshold shown in the annualaudiogram indicates significant improvement overthe baseline audiogram.OSHA’s former recording criteria required theemployer to track separate baselines for recordingand hearing conservation purposes. However, thenew Part 1904 hearing loss recording system relieson the existing 1910.95 calculations, and separatebaselines will no longer be required. In short, underthe new Part 1904, a recordable hearing loss caseoccurs when an employee experiences an STS (asdefined in 29 CFR 1910.95), the STS is work-related,and the employee’s aggregate hearing loss exceeds25dB from audio metric zero.[67 FR 44044-44047, July 1, 2002]Work Relationship... [T]he final rule states that there are no special rulesfor determining work-relationship and restates therule’s overall approach to determining work-relatedness-- that a case is work-related if one or moreevents or exposures in the work environment eithercaused or contributed to the hearing loss, or significantlyaggravated a pre-existing hearing loss.The final rule’s approach to determining workrelatednessdiffers from the January 2001 rule forthree reasons. First, although it is likely that occupationalexposure to noise in excess of 85 dBA will be acausal factor in hearing loss in some cases, a presumptionof work-relatedness is not justified in allcases. Further evaluation is needed to make thisHANDBOOK93§1904.10