Response to Suter and NIOSH

Abstract

492We thank Suter and Morata et al. for their letters. The authors of Morata et al. are all employees of the National Institute for Occupational Safety and Health (NIOSH); it is our understanding that their letter, lacking the disclaimer usually attached to public comments of federal employees, represents the official position of that agency, and thus, we will refer to it as the NIOSH letter. We will address each of the comments in the Suter and NIOSH letters, followed by a brief discussion on important issues that they omitted. Although we would have preferred a brief response, the extent, nature, and scientific foundation of the arguments brought forward require a thorough rebuttal.Suter and NIOSH are longtime collaborators and proponents of the 3-dB exchange rate (ER), so their disagreement with our article is not unexpected. What was unexpected was NIOSH's assertion that a "re-examination of the exchange rate" requires adherence to a long list of criteria, including the use of two raters of study quality, with a third to adjudicate conflicts; a formal assessment of quality across multiple domains; attempting to contact authors; presenting study findings grouped by "certainty of exposure level estimates"; an evaluation of the risk of bias; and others. We disagree and note that neither NIOSH (1998) nor Suter's (1992) report to NIOSH considered any of these elements when they re-examined the 5-dB ER, which NIOSH (1972) had previously recommended, and decided to instead advocate for the 3-dB ER.For those who have not read our article, we reviewed all the literature we could find that could shed light on the issue of the appropriate ER, based on human noise-induced permanent threshold shift (NIPTS). We included every study that had been cited by Suter (1992) and NIOSH (1998), as well as other studies from the reference lists of those articles, and additional studies discovered by a literature search. We applied clear inclusion criteria, analyzed included studies in comparison with the predictions of an international standard (International Organization for Standardization [ISO]-1999[ISO]- , 1990) using fully transparent methodology that others can replicate, and submitted our work to a peer-reviewed journal. We believe that our contribution was unique in this literature. We could not replicate the findings of a frequently cited previous review (Passchier-Vermeer 1973) that despite its unclear methodology and lack of peer review has been very influential (as we note later). Although we reviewed 19 studies in detail and included nine in our summary table, it is notable that neither Suter nor NIOSH question any of our exclusions, nor do they suggest alternative interpretations for any of the included studies. Suter notes that we "excluded most of the studies used by Passchier-Vermeer from their analysis." That is misleading: we read, analyzed, and commented on all the studies Passchier-Vermeer relied on and explained why most of them had to be excluded from our final summary table.Some studies that NIOSH now conside...

Occupational Noise: Auditory and Non-Auditory Consequences

“…While this may not seem like a large difference, some studies indicate that deploying a 3-dB exchange rate in OSHA regulations would identify 1.5-3 times as many workers as being potentially at risk for NIHL [6,26]. In fact, the debate over the use of a 3-dB or 5-dB exchange rate has been ongoing for some time, and still continues today [27][28][29][30][31][32]. NIOSH also recommends an upper ceiling peak pressure limit of 140 dB(A) and recommends that a hearing conservation program be established for workers exposed to an 8-h time-weighted average (TWA) of 85 dB(A).…”