In 1979, ONAC ran afoul of the waste management industry by proposing regulations requiring longer trash truck compactor cycles to reduce noise. These activities were never adequately funded or supported. The Noise Control Act of 1972 established a national policy to promote an environment for all Americans free from noise that jeopardized their health and welfare, with federal noise control activities assigned to the EPA. Although noise was known to be a health hazard, it was treated as an environmental pollutant. Why has little been done to control noise in the United States? The reasons are complex. Noise also has nonauditory health impacts-increases in stress hormones, hypertension, obesity, cardiac disease, and mortality-at average daily exposures of only 55 decibels, with activity interference beginning at 45 decibels. 3 (The decibel scale is logarithmic, so 85-decibel sound has 31.6 times more energy than 70-decibel sound, not 21% more, as might be commonly thought.) The EPA did not adjust for lifetime noise exposure, now almost 80 years versus 40 work-years, so the real average safe noise level to prevent hearing loss is probably lower. The EPA calculated the safe noise level for the public to prevent hearing loss to be a 70-decibel time-weighted average for a 24-hour period (L eq(24) = 70). In 1974 the Environmental Protection Agency’s (EPA’s) Office of Noise Abatement and Control (ONAC) adjusted the National Institute for Occupational Safety and Health recommendation for additional exposure time: 24 instead of 8 hours daily and 365 instead of 240 days annually. 2 Noise is different from other occupational exposures (e.g., toxic solvents or ionizing radiation) because exposure also occurs outside the workplace. The 85 A-weighted decibel standard also assumes workers have quiet when not at work, which is no longer true for many Americans.Īn occupational noise exposure standard is not a safe standard for the public. Even with strict time limits, this standard does not protect all workers from hearing loss. At 85 A-weighted decibels time-weighted average exposure, an employer must implement a hearing conservation program, including serial audiograms and provision of hearing protection. The Occupational Safety and Health Administration adopted this as a legal standard for workplace hearing protection. In 1972, the National Institute for Occupational Safety and Health developed an 85 A-weighted decibel recommended exposure level to reduce the risk of hearing loss from occupational noise exposure. A discussion of the decibel scale and weighting adjustments is beyond the scope of this editorial.)Įighty-five decibels is not a safe noise exposure level for the public. The decibel measurements used by each organization are cited as used. (Different organizations use A-weighted decibel measurements or unweighted decibel measurements. This is demonstrated by the use of 85 decibels as a safe sound level by hearing health professionals and their organizations, in media reports, and in publications, most often without time limits by its use as a volume limit for children’s headphones marketed to prevent hearing loss, again without exposure times and by general acceptance of higher indoor and outdoor noise levels in the United States. What is a safe noise level for the public? The National Institute on Deafness and Other Communication Disorders states, “Long or repeated exposure to sound at or above 85 decibels can cause hearing loss.” 1 In the absence of a federal standard, an occupational standard meant to prevent hearing loss appears to have become the de facto safe level for all public noise exposures.
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