‘Poison of the ear’ – Ototoxicity in industry – SHPonline

Noise and vibration

Gordon Pringle

There is sufficient evidence and research dating back to the 16^th century that noise exposure can cause hearing loss. Ramazzini’s published notes on the Diseases of Workers, which identified how Italian coppersmiths suffered noise-induced hearing loss (NIHL) after years of hammering and forge work. However, some OHS professionals may only recently be aware of ototoxicity, also known as ‘poison of the ear’. Exposure to ototoxic chemicals can cause headaches, dizziness, tinnitus (ringing inside the ears) and occupational-induced hearing loss (OIHL), as Gordon Pringle explains.

Pharmaceuticals

Various medication has already been identified as causing ototoxic affects in patients; from simple Ibuprofen, antibiotics like aminoglycosides and even antimalarial drugs (RNID, no date). Often after long-term treatment, patients have reported hearing loss, tinnitus, or problems with their balance as the small fragile hairs of the inner ear are damaged.

Industrial chemicals

More relevant to the occupational environment are the various chemicals which have an ototoxic effect. Recent studies including by the World Health Organization (2021, pp. 21) now cite solvents, heavy metals, asphyxiant gases, nitriles, and some pesticides within the list of ototoxic chemicals. These substances can have a severe effect on the workforce and their hearing and balance once inhaled, absorbed, or ingested in an occupational setting.

Prevention

Within the workplace we are already aware of occupational exposure limits (OEL’s) to limit the effect of chemicals on workers, however limited inclusion of their ototoxic effect is considered within the levels set in the Health and Safety Executive’s EH40.

Identification is important within Control Of Substances Hazardous to Health (COSHH) assessments to know which ototoxic chemicals are in the workplace and how the workforce is exposed. Then the hierarchy of control, starting where possible with the elimination of these chemicals, should be employed.

A good start to identification would include checking the manufacturers’ Safety Data Sheets of any paints, cleaning solvents and even gardening and agricultural supplies. Key constituents with known ototoxic effects include:

• Arsenic.
• Benzene.
• Carbon Disulfide.
• Styrene.
• Trichloroethylene.
• Toluene.
• Xylene.

However, some ototoxic chemicals may also be a by-product of processes, specifically carbon-monoxide.

Most of these everyday chemicals, like benzene from petrol fumes, are likely to be with us in the workplace for some time so elimination is a limited possibility, as is substitution. Therefore, engineering controls such as segregation, local ventilation, dilution and general ventilation will play a large role in control measures, along with supervisory control to ensure exposure is suitably controlled. Only then should personal protective equipment be considered – although all routes …….

Source: https://www.shponline.co.uk/noise-and-vibration/poison-of-the-ear-ototoxicity-in-industry/