NOISE ASSESSMENT AT WORK
Advice on managing noise risks
Ototoxic chemicals or products
What are ototoxic and what should companies do about them
What the risks to employees are
“Thank you for the report. Very comprehensive with good, easy to understand information for us to make improvements
and changes where necessary”. QHSE Manager, Hull, 2022
When looking at the noise risks your employees are subject to at work, part of it should be a check to see if Ototoxic chemicals are present, and if so, are employees exposed, especially anyone identified as being at high risk.
Before diving into it, some explanation of the key parts there:
Ototoxic means poisonous to ears and exposure to them can permanently damage hearing, or make the effects of noise exposure worse.
A ‘high risk’ person is someone with a known sensitivity to ototoxic materials, and who may or may not already have some kind of weak hearing. How do you know this? A hearing test can identify people with weak hearing, but only medical tests and reports from GPs, specialist investigations at hospitals, etc. being reports via the employee themselves can let you know if they have this sensitivity.
Helpfully, there are currently no risk phrases for Ototoxicity in EH40 and you normally will not see it on a Safety Data Sheet - unlike many other chemicals and their risks you cannot simply look it up there.
What kind of chemicals are ototoxic?
To make a clarification, we are talking about ‘in connection with work’ here. Many many drugs are ototoxic, such as some antibiotics, Ibuprofen, etc. but we are only looking at stuff people may come into contact with as part of their work, either as a product they use or as a product they produce.
Ones to look out for are:
Arsenic - microorganism inhibitors
Benzene - plastics, paints, cleaning agents
Carbon disulphide - pesticides
Carbon monoxide - work around vehicles, clothes dryers, petrol-powered tools, etc.
Cyanides
Germanium
Lead
Mercury
Styrene - plastics and insulating materials
Tin
Toluene - paints, lacquers, adhesives, rubber, etc.
Trichloroethylene - dry cleaning, paints, waxes, pesticides, lubricants
Xylene - Paints, varnishes and thinners
What are the symptoms to look out for?
Symptoms vary between people, which is one reason pinning down firm exposure limits is so hard. They can cause tinnitus and balance problems ranging from mild to total.
Signs of balance problems include dizziness, difficulty walking, blurry vision, walking with legs apart for steadiness, problems walking in the dark, light-headedness, feeling weak.
Ototoxic chemicals can cause mild to severe hearing loss, or total hearing loss, depending upon each person, and the form and level of exposure. Most of the time the symptoms will go away with removal from the substance, but for the more severe symptoms the issues can become permanent.
From a noise perspective, our main worry is that ototoxic chemicals can make people more susceptible to developing hearing losses. I.e. They may be perfectly fine with regular exposures to say 85 dB(A) when not exposed to ototoxic chemicals, but when exposed that same noise exposure can make the noise damage hear far more than it otherwise would have.
Look out for employees who, after spending time at work:
Often develop headaches
Get periods of dizziness
Can have trouble with balance
Identifying people at risk of ototoxicity
This is where it gets complicated and we are afraid there is no nice and easy principle such as ‘all Category 3 people are at risk’, as they aren’t, not by a long way.
While we know certain chemicals may have an impact, the only way for ototoxicity to be confirmed as having an impact on someone is by detailed medical testing, and way beyond anything which will be done at work. This will likely involve a GP and referral to a specialist department in hospital, along with detailed investigation into the chemicals used. You will not confirm people as specifically at risk from this via a noise assessment or workplace screening and the most important thing is to prevent exposures in the first place.
What should companies be doing about ototoxic products?
At this stage, with no fixed exposure limits, it comes down to ‘getting ahead of the issue’ really.
Go through the CoSHH assessments and look to see if you have any of the products listed above, or if any of the chemicals you use or produce contain one of the above as an ingredient.
Look to see if anyone is exposed to these via touch or inhalation.
Minimise those exposures where you can.
That’s pretty much your lot for now.
The only other issue to watch out for then is feedback from someone who has been referred following a hearing test, their GP has then arranged for a specialist examination, and the outcome from that identifies a sensitivity to a chemical or group of chemicals.