Can Industrial Chemical Exposure Cause Hearing Loss?
It is important to remember that any chemical that is ototoxic is also likely to be poisonous to the kidneys, because the inner ear and the kidneys arise from the same germ layer during embryonic development.
The short answer to the question in the headline is an unequivocal “yes!” There are industrial chemicals in common use that are ototoxic (poisonous to the ears), meaning that they can damage hearing just as easily as industrial noise. However, simultaneous exposure to noise and ototoxic chemicals is particularly insidious because of their synergistic effect.
In order to illustrate a synergistic relationship, let’s suppose a given noise exposure is responsible for a 10-dB threshold shift. Let’s also suppose that an ototoxic chemical, by itself, can induce a 10-dB threshold shift. If exposure to the noise and ototoxin together results in a 20-dB threshold shift, then we say the combined effect is additive. A synergistic effect, however, is one in which the combined impact of the noise and ototoxin results in a much greater total threshold shift than would be predicted by simply adding together the noise- and ototoxin-related threshold shifts—perhaps a 35- or 40-dB threshold shift may occur. Also, such a threshold shift often impacts a wider range of frequencies. Indeed, a synergistic effect is greater than the sum of its parts, and this observation has been borne out by research involving industrial workers.