Solving the Noise Induced Hearing Loss Problem by Asking the Right Questions: Part One of a Two Part Series
By Jeffrey Goldberg
As former U.S. Surgeon General William Stuart once said, “Calling noise a nuisance is like calling smog an inconvenience. Noise must be considered a hazard to the health of people everywhere.”
People have known this about noise and its effects on hearing for decades and yet noise-induced hearing loss (NIHL) remains epidemic in the workplaces of America. Why? Maybe as Bertrand Russell once noted, “In all affairs, it’s a healthy thing now and then to hang a question mark on the things you have long taken for granted.”
Noise Induced Hearing Loss Problem: Regulating Noise
Let’s examine why we haven’t made more progress eliminating NIHL. It starts with the history of noise as an industrial hazard. The history of hazardous noise is well defined. As early as the beginning of the last century, noise was recognized as an industrial hazard.
Though the measure of the noise was difficult to achieve at that time, because it wasn’t accurately measurable, NIHL was recognized but not quantified nor were any limits on exposure set. After a series of studies by the military and military sponsorship of civilian laboratories after World War II through the mid-1960s, 90 A-weighted decibels (dBA) was determined to definitely be a level above which actions to limit exposures were necessary. Therefore, 90 dBA was written into the U.S. Occupational Noise Standard in 1969 as part of the legislation as the permissible exposure limit (PEL). The Occupational Safety and Health Administration (OSHA) was directed to develop the rest of the regulation to define the steps necessary to form an effective hearing conservation program.
It is recognized that approximately 25 percent of workers whose daily exposure level (LEX,8h) is above 90 dBA will develop NIHL. Although the National Institute for Occupational Safety and Health (NIOSH) revised its own recommended exposure limit down from 90 to 85 dBA and further recommended a 3-dB exchange rate instead of the earlier 5-dB exchange rate in the legislation, today the 90 dBA PEL remains in the U.S. OSHA regulation.