Chemical and Noise Exposure Together Increase Risk of Hearing Loss

Came across this article in the ASHA Leader this weekend. Thought it was a good, quick read. Interesting to note that research is showing that “ototoxic chemicals might exacerbate noise-induced hearing loss even though the noise level is acceptable.”

Chemical and Noise Exposure Together Increase Risk of Hearing Loss

Workers exposed to acceptable levels of both noise and ototoxicants face an increased risk of hearing loss, indicates new federal guidance on hearing loss prevention in the workplace.

The effects of the combination of exposures are “greater than additive,” according to the document released by the Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health. Many ototoxic substances have a synergistic effect with noise exposure on hearing loss, and some ototoxic chemicals might exacerbate noise-induced hearing loss even though the noise level is acceptable.
“Millions of workers are exposed to noise in the workplace every day and when uncontrolled, noise exposure may cause permanent hearing loss,” the document says. “Research demonstrates exposure to certain chemicals, called ototoxicants, may cause hearing loss or balance problems, regardless of noise exposure. The risk of hearing loss is increased when workers are exposed to these chemicals while working around elevated noise levels.”
The combination can cause temporary or permanent hearing loss, depending on the level of noise, the dose of the chemical, and the duration of the exposure.
Exposure to ototoxicants may occur through inhalation, ingestion or skin absorption. Ototoxicant-induced hearing loss may go unrecognized, however, because audiometric tests do not indicate causes of hearing impairment.
Occupations that may have high noise and ototoxicant exposure include printing, painting, construction, firefighting, weapon firing, pesticide spraying and many manufacturing industries (fabricated metal, machinery, petroleum, paper, chemical and paint, furniture, transportation equipment, electrical equipment, and others).
The guidance document, which is not a standard or regulation, suggests employers take steps to prevent hearing loss:
  • Identify ototoxicants in the workplace. Review Safety Data Sheets for ototoxic substances and chemicals, and for ototoxic health hazards associated with ingredients in the products. These required documents—prepared by manufacturers, distributors or importers—accompany hazardous chemicals and substances and outline their dangers, composition, safe handling and disposal.

  • Provide, in plain language, health information, safety information, and training to workers exposed to ototoxic chemicals.

  • Investigate Safety Data Sheets if workers report hearing loss.

  • Replace a hazardous chemical with one that is less toxic. If that is not possible, use engineering and administrative controls to limit exposure to ototoxicants and noise.

  • Determine the required personal protective equipment (general, respiratory and hand). To reduce skin absorption, consider chemical-protective gloves, arm sleeves and aprons.

  • Test for noise exposure.

  • Encourage the use of hearing protection and audiometric testing, even when noise and ototoxicant exposure levels are acceptable, to prevent hearing loss from synergistic effects.


The ASHA Leader, June 2018, Vol. 23, 10-11. doi:10.1044/leader.NIB1.23062018.102018-06-04 13:43:02

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