When we think of hearing loss, we often think it is either from a genetic disorder or getting older. Both of these types of hearing losses are accurate and happen, but have you ever heard about hearing loss from chemical exposure? Hearing loss from chemical exposure is called ototoxicity.
According to the Centers for Disease Prevention and Control (CDC), millions of workers are experiencing hearing loss from uncontrolled noises and certain chemicals, such as pesticides, solvents, and pharmaceuticals. These ototoxins can affect how the ear functions creating possible balance issues and a loss of hearing ability.
Types of Ototoxic Chemicals
Ototoxic chemicals are classified in the following ways spending upon where they damage the ear:
- Neurotoxicants – Neurotoxicants are ototoxic when they damage the nerve fibers that interfere with hearing and balance.
- Cochleotoxicants – Cochleotoxicants mainly affect the cochlear hair cells, which are the sensory receptors, and can impair the ability to hear.
- Vestibulotoxicants – Vestibulotoxicants affect the hair cells on the spatial orientation and balance organs.
Common Ototoxic Chemicals
The following chemicals can be found at work, home, or in both environments:
- Benzene – plastics, paints, cleaning agents, cigarette smoke
- Carbon disulfide – pesticides
- Carbon monoxide – cigarette smoke, welding, gasoline-powered tools and vehicles
- Styrene – plastics, insulating material
- Trichloroethylene – paints, waxes, pesticides, lubricants, rug cleaners, spot remover
- Toluene – paints, lacquers, adhesives, rubber, leather tanning, spray paint.
- Xylene – paints, varnishes, thinners
How Do Chemicals Affect Hearing?
The chemicals enter the body and reach the inner ear through the bloodstream, damaging the hearing. Ototoxic chemical exposure can happen in the following ways:
- Inhalation – the chemicals are breathed in through the nose and mouth
- Ingestion – the substances enter the body by swallowing it, the same way as food or drinking.
- Skin Absorption – the chemicals penetrate the skin and absorb into the circulatory system.
These toxic chemicals entering the body can come from fumes, mists, gases, or vapors, and over time damage the nerve fibers and hair cells inside the ear, resulting in hearing loss, tinnitus, and problems with balance. The effects of exposure will vary upon the exposure frequency, intensity, duration, and workplace hazard. People will be affected differently depending upon their genetic predisposition, age, and health. The hearing loss may be increased with the combination of loud, damaging noises.
What Types of Jobs are Most at Risk?
The jobs that pose a greater risk for hearing loss from ototoxic chemicals are:
How to Protect from Ototoxic Chemicals
The U.S. Department of Labor, Occupational Safety and Health Administration (OSHA) recommends replacing all ototoxic chemicals wherever possible. If unable to do so, workplaces should reduce the risks by installing exhaust fans, jets, ducts, hoods, and separators to draw fumes, mists, gases, and vapors away from the work area.
Any chemical in the workplace should have a Safety Data Sheet (SDS) to explain any possible hazards that may be present. When working in an environment with chemicals present, if you begin experiencing any of the following symptoms, such as headache, feeling of fullness in the ear, dizziness, or blurry vision, be sure to leave the area and find fresh air to breathe.
All employees should wear personal protective equipment, including:
- Gas/Vapor Respirators
In addition to protecting against ototoxic chemicals, those working in jobs with potential exposure should also be sure to wear ear protection to lessen the harms of loud construction equipment.
If you are experiencing any hearing loss, be sure to be seen by a hearing professional to see what hearing improvements can be possible for you and find out how you can reduce further damage.