Another study examined the hearing threshold of hockey officials and found mean noise exposures of 93 dBA. Hearing threshold shifts were observed in 86% of the officials (25/29).In a study of noise levels at 10 intercollegiate basketball games showed noise levels in 6 of the 10 basketball games to exceed the national workplace noise exposure standards, with participants showing temporary threshold levels at one of the games.While there is no agency that currently monitors sports stadium noise exposure, organizations such as NIOSH or OSHA use occupational standards for industrial settings that some experts feel could be applied for those working at sporting events. Workers often will not exceed OSHA standards of 90 dBA, but NIOSH, whose focus is on best practice, has stricter standards which say that when exposed to noise at or exceeding 85 dBA workers need to be put on a hearing conservation program. Workers may also be at risk for overexposure because of impact noises that can cause instant damage. Experts are suggesting that sports complexes create hearing conservation programs for workers and warn fans of the potential damage that may occur with their hearing.Studies are still being done on fan exposure, but some preliminary findings show that there are often noises that can be at or exceed 120 dB which, unprotected, can cause damage to the ears in seconds. Mechanisms
NIHL occurs when too much sound intensity is transmitted into and through the auditory system.
Among people aged 20–29, 19.2% had an audiometric notch, compared to 27.3% of people aged 50–59. Males in general had a notch more often than females, regardless of occupational noise exposure, for both unilateral and bilateral audiometric notches. An epidemiological study of 6557 automotive manufacturing workers in China (median age 28 years old) reported that in 62% of the settings where noise exposures were evaluated, levels exceeded the recommended level of 85 dBA. The prevalence of hearing loss was 41% among auto part manufacturing workers, followed by 31% of power train workers and 24% in automotive manufacturing. Across job categories, the highest prevalence rate was observed among welders, of 53%. The prevalence rates were associated with noise levels and the workers cumulative noise exposure. Occupational noise exposure is the main risk factor for work-related hearing loss. One study examined hearing test results obtained between 2000 and 2008 for workers ages 18–65 who had a higher occupational noise exposure than the average worker. Of the sample taken, 18% of the workers had hearing loss. Of the occupations considered, the Mining industry had the highest prevalence and risk of hearing loss, at approximately 27%. Other industries with a higher prevalence and risk included Construction (23.48%) and Manufacturing, especially Wood Product and Non-metallic Mineral Product (19.89%), Apparel (20.18%), and Machinery (21.51%). Estimates of rates of hearing loss have been reported for workers in the Agriculture, Forestry, Fishing, and Hunting (AFFH)  sector.