Acoustic shock – emerging risk?
Following the case of Goldscheider –v ROH (2019), acoustic shock cases are an emerging risk and there is a risk of a floodgate of similar claims.
They are a potential problem for three reasons:
- They have a potential for high value
- They may be more difficult to defend than traditional Noise Induced Hearing Loss (NIHL) claims and
- They may be imported into new settings.
As such they represent an important issue for insurers and industry.
Acoustic shock is an injury which can allegedly arise from isolated, limited exposures to noise at a noise level not previously thought harmful. The claims originally arose from headsets in call centres where the noise was channelled into the ear canal. They are now being presented in new contexts outside of call centres following Goldscheider.
The claimant in Goldscheider was exposed to the noise of trumpets in the orchestra pit of the Royal Opera house during a rehearsal. Conventionally, that exposure would not have been sufficient noise dose to evidence an injury.
It had previously been understood that noise gave rise to injury in two ways:
- Acoustic Trauma: exposure to sudden very high ‘peak action’ exposure above 135dB(C) such as an explosive or impulse noise which causes acute damage to ear drum, cochlea
- NIHL being long term, cumulative damage over years above at least 85dB(A) which causes damage to hair cells in the cochlea. It is well known that to establish NIHL, objective diagnostic criteria must be met, including sufficient daily and lifetime noise dose.
Acoustic shock represents an alleged third mechanism - where much lower levels of noise well below peak action levels give rise to an injury. Even a few seconds exposure to say 100dB(A) could allegedly cause this injury. This is reportedly caused by a ‘startle response’ to a muscle in the inner ear and result in a cluster of subjective symptoms often including vertigo, pain, dizziness and tinnitus. This is a highly controversial condition for which very little clinical or epidemiological evidence exists. The condition may be entirely psychogenic in origin or include an element of psychological overlay. It is often present where there is discontent among workers. There is no objective proof of injury and there is dispute as to whether the condition even exists, especially if the noise is not channelled into the ear canal. Significantly- unlike NIHL- no objective diagnostic criteria applies and no minimum noise dose is required.
The High Court found on balance that the condition did exist. The Court of Appeal did not disturb the findings of the High Court on causation and, in doing so, gave credibility to this contentious disorder. They stated in line with authority that the fact this particular type of sudden injury had not been foreseen was irrelevant, since a known risk did arise from exposure to noise.
It will now be more difficult for a defendant to argue that occasional, infrequent exposure to high noise below peak action level would be an unforeseeable risk and therefore uncompensatable. We can expect claims to be presented in new work scenarios where, for example, there is transient exposure to the noise of horns, sirens, alarms etc.
If these claims do emerge they can be serious as there can be an effect on employability with a resulting Smith v Manchester award. This can make these claims high value.
It is however also significant that the Control of Noise at Work Regulations 2005 were in fact breached in the Goldscheider case. The Regulations place high duties on a defendant. The risk must be either eliminated at source, or where this is not reasonably practicable, reduced to a level “as low as is reasonably practicable (ALARP)”. In considering ‘ALARP’ risk, it would be prudent to undertake a cost/benefit analysis of mitigating the risk against the frequency and severity of the risk.
Consideration should also be given to potential steps to deal with the risk of injury and resulting claims:
- Risk assess sudden noise output
- Consider steps to take
- Document cost/benefit analysis
- Eliminate with engineering methods
- Reduction – e.g. ear protection.
- Consider breach
- Exercise caution in making admissions, since causation is closely linked to breach
- Consider causation such as competing causes
- Investigation – what steps were taken?
- Medical experts – consider appointing audiovestibular experts
- Consider need for psychiatric experts.
Given the credibility lent to the condition by this case, insurers and industry should now be aware of steps to take to mitigate the risk of injury and resulting claims. A robust approach will be required in dealing with these claims to avoid a floodgate. Thought should be given in future to obtaining epidemiological and expert evidence to refute this highly contentious condition.
Read others items in Occupational Disease Brief - November 2020