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familiar with the product and the earplug is properly fitted to help achieve the maximum reduction in noise.

However, once in the industrial setting where workers typically fit their own hearing protection devices, the results are not as favorable. An employee may improperly insert the earplugs due to inadequate instruction or select the wrong ones for the environment. This may result in the wearer’s discomfort and/or inadequate protection. Often hearing protectors will deteriorate without the worker’s knowledge.

In the testing procedure, attenuation data on hearing protectors is typically reported across seven or nine test frequencies and also as a Noise Reduction Rating (NRR), a single-number rating required on all hearing protection product labels.

In recent years, a number of researchers have tried to estimate the actual protection that the industrial workers received from earplugs. Studies were performed in industrial plants and laboratories. Ten of these studies were summarized in 1983 in a comprehensive review by Elliott Berger, a researcher at EAR Corporation. It was found that the average manufacturers’ claim was that the NRR of earplugs was 20 dB. Later, an independent study of the “real world NRR” based on the attenuation received by workers in the industrial environment proved that workers received an average of five dB of protection, one-fourth of the manufacturers’ claim.

Hearing protection programs are one way that the industry can protect its workers and in some cases, defend itself against litigation. But as Casali warns, “Ideally, noise should be stopped at the source or in its transmission path, not at the receiver ... But because protection devices are cheaper and easier to implement than many engineering controls, they will continue to be popular.”