Publications by authors named "Nicholas C Schaal"

Objectives: The purpose of this retrospective cohort study was to compare the relative risks (RR) of hearing impairment due to co-exposure of continuous noise, impulse noise, metal ototoxicants, and organic solvent ototoxicants using several pure tone audiometry (PTA) evaluation methods.

Design: Noise and ototoxicant exposure and PTA records were extracted from a DoD longitudinal repository and were analyzed for U.S.

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Background: Personnel assigned to aircraft carriers work and live in environments where hazardous noise areas and hearing recovery spaces such as sleeping areas are in close proximity to one another. Hazardous noise exposure occurring during on-duty time periods and elevated noise levels during off-duty periods in sleeping areas may be prohibiting adequate hearing recovery, thus potentially leading to hearing loss and may lead to adverse effects on sleep, leading to crew-member fatigue. This investigation characterizes Equivalent sound level (Leq) and standardized octave band center frequency noise levels according to berthing (sleeping) area location during flight operation and nonflight operation time periods on a US Navy aircraft carrier.

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Background: Personnel assigned to aircraft carriers are exposed to a variety of noise sources from equipment and flight deck operations for durations >12 h. Personnel work and live in environments where hazardous noise areas and hearing recovery spaces such as sleeping and relaxation areas are in proximity to one another which provides little recovery time from hazardous noise. This investigation describes noise levels measured over a 24-h period on a US Navy aircraft carrier during flight operations for different populations of aircraft carrier personnel.

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Objective: The aim of this study was to determine the effect of lead, cadmium, arsenic, toluene, and xylene exposure on hearing compared with noise exposures alone.

Methods: Personnel at a shipyard (n = 1266) were divided into four exposure groups on the basis of concentrations: low metals/low solvents/high noise (reference group), high metals/high solvents/low noise, high metals/low solvents/high noise, and high metals/high solvents/high noise. Hearing changes occurring from the years 2004 to 2015 were analyzed.

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Background: Occupational exposure to methylene bisphenyl isocyanate (MDI) presents serious worker health concerns as it may lead to short- and long-term health effects such as asthma, airway irritation, hypersensitivity pneumonitis, and irritation of skin and mucous membranes. While studies of worker isocyanate exposures during vehicle painting activities are widespread, few studies have investigated the spray-on truck bed-liner (STBL) industry. The purpose of this study was to determine the effectiveness of several ventilation system variables and process characteristics in controlling MDI concentrations in the STBL industry.

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