When is a trivial hearing loss so minimal that it becomes inactionable? Defendants seldom have defences to avail of in defending NIHL cases particularly when dealing with historical cases where the alleged breach of duty happened 30/40 years beforehand and records have been destroyed, employees have retired or companies have dissolved. One potential avenue may be to argue that the hearing loss is de minimis i.e. so trivial that compensation will not follow.
In another area of industrial disease case law we had the decision in Rothwell v Chemical & Insulating Company Ltd  UKHL 39 where the majority of the House found that asymptomatic pleural plaques did not constitute personal injury and no cause of action could be pursued. Lord Hoffman in discussing the de minimis principle said the test was whether someone was "appreciably worse off"?
What does that mean in practical terms? The authorities have fluctuated in their guidance
In Baker v Quantum Clothing Group Ltd  UKSC 17 Judge Inglis said as regards a de minimis argument "The smallness of a level of risk may be relevant in assessing how an employer should act in particular circumstances. It does not prevent compensation for hearing loss being appropriate where the impairment has led or will lead to some level of disability, even if only minor....the key decision in my judgement is whether a real degree of noise induced impairment can be confidently diagnosed on the balance of probability."
However two subsequent first instance decisions appear to contradict that view. In Hughes v Rhondda Cynon Taff County Borough Council  Unreported Cardiff County Court the plaintiff had been employed as a labourer with the Defendant from 1969 to 2006 and the Defendant mounted a de minimis defence. Five audiograms were before the court, none of which showed any hearing disability in the 1-3 kHz frequencies. The Plaintiff's medical expert argued that losses at 4kHz gave rise to a disability. It was common case that there were a few decibels of loss at 4 kHz caused by noise. The Judge found that the NIHL at 4kHz did not give rise to any disability and the change in hearing fell within the de minimis principle so as not to be actionable.
In Holloway v Tyne Thames Technology in May 2015, Newcastle County Court adopted the approach in Hughes. Judge Freedman accepted the test to be applied was whether the plaintiff was appreciably worse off on account of the NIHL as per Rothwell. Breach of duty had already been established. Ther was a disagreement between the medical experts as to the quantification of the noise loss. Plaintiff's expert opined 6 or 9dB average noise loss. Defendant's expert opined 1.3dB. Judge Freedman was not satisfied that even a loss of 3dB was an appreciable loss. The Judge accepted the plaintiff had a 30dB loss in each ear not noise related. The readings were 40dB and 45dB respectively. THe Defendant's expert successfully argued that while the claimant might notice the loss it would be so rarely that she would not be materially affected.
Obviously this decision is not binding but it will be of value to defendants' solicitors to argue that losses of up to at least 3 dB in the 1-3kHz hearing range frequencies and losses of up to at least 15dB at 4kHz are de minimis and not compensatable.
Murphy O'Rawe 'To Lead and to Guide.'
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