OCCUSAFE UPDATE
Monthly Round Up of Important Ideas and Standards in
Industrial Hygiene and Safety
August 2020
IN THIS ISSUE: Ototoxins
Noise exposure has been shown to be the main cause of hearing loss in the workplace. In addition, certain chemicals can damage the inner ear once they are introduced into the body through inhalation, ingestion, or absorption. These substances are known as ototoxins. Ototoxins such as toluene can also have a combined or synergistic effect with noise that can further affect hearing.
Examples of ototoxins include solvents such as carbon disulfide, ethylbenzene, styrene, toluene, trichloroethylene and xylene, heavy metals including lead and mercury, and asphyxiants such as carbon monoxide. Certain nitriles and pesticides may also damage hearing. Specific pharmaceuticals are known ototoxins.
Various types of chemicals have different effects on hearing. They include:
- Decreased blood flow into the inner air, which causes a lack of oxygen and can damage the hair cells (cilia).
- Increased activity of cilia, which can produce free radicals that can cause damage to the inner ear.
- Decreased antioxidants that promote hearing health.
- Disruption of transmission of signals in the ear from exposure to neurotoxins.
- Interference of calcium regulation that affect cilia length.
Although OSHA does not include chemical exposures in their hearing conservation standards, it did publish a bulletin, “Preventing Hearing Loss Caused by Chemical (Ototoxicity) and Noise Exposure” in March, 2018. It includes useful information and provides a list of industries that use ototoxins and processes that have a combined effect with noise.
It is important that facilities in these industries take an inventory of their ototoxins and identify processes where they may used. If employee exposure levels approach the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLV) for these chemicals or where these exposures are in combination with noise at 85 dBA or less for an eight-hour day, they should be included in a hearing conservation program. This should be combined with training and controls that limit noise and exposure to ototoxins
OccuSafe Industrial Hygiene & Safety, Inc. provides skills and expertise to recognize, evaluate and control hazards and injuries in the areas of industrial hygiene, occupational safety and health. OccuSafe services companies of all sizes in a range of industries.
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