Firefighting is one of the most hazardous jobs. According to the United States National Fire Protection Association (NFPA) [15], there are over 1 million American firefighters who are at risk of developing NIHL at work. Noise exposure for firefighters is typically high in intensity and short in duration, unlike the steady and constant exposure experienced by workers in manufacturing industries. Noise survey data have consistently demonstrated that firefighters are exposed to dangerously high noise levels, exceeding