A word in your ear

Advice is given on how to decide whether to stand and fight or beat a
strategic retreat when an employee makes a claim for occupational noise-induced
hearing loss.  By Dr S J Karmy

With Police Constable Alan Ross launching a £15,000 claim against the Grampian
Police this spring for a hearing loss allegedly caused by 14 years of noise
exposure to the barking of police dogs, it is difficult to know from which
direction the next noise-induced hearing loss claim will come.

The government of Southern Ireland understands this, as it has paid out
£104m since 1996, after a sizeable portion of the Irish Army claimed against it
for noise-induced hearing loss caused during training. A total of £85m was set
aside in the 1998 defence budget for settling claims and it is thought that the
final cost will top out at between £144m and £160m.

This is far from being an Irish phenomenon, however. Figures produced by the
Association of British Insurers suggest that the number of claims for
noise-induced hearing loss is running at roughly a third of the total claims
faced by insurers for all types of industrial injuries. Add to this the current
campaign by the TGWU to highlight the acoustic problems faced by employees in
the UK’s rapidly growing call centre workforce, plus the financially
compounding effect of adding noise-induced tinnitus to a claim for
noise-induced hearing loss, and it can be seen that the need to monitor the
hearing of employees in British industry is as high as ever.

Previous articles by the present author have emphasised the value of
industrial audiometry in protecting the hearing of noise-exposed employees,
which it does in a variety of ways.

Undoubtedly, this is the main objective of a programme of hearing testing,
but the rest of this article explores what can be done with the audiometric
results to allow the employer to defend itself against undeserved claims, and
to justify payment to those with reasonable grounds for legal action.

Reacting to a claim

Given the nature of the slimmed-down human resources and occupational health
departments of the 2000s, a difficult judgement needs to be made when a claim
arises. How do you decide whether you should stand and fight, or beat a
strategic retreat?

It is all too tempting to hand the whole matter over to your insurer for
action, but as likely as not, it will wish to settle the claim quickly for you
out of court. This is not as generous as it seems, for next year your insurance
premium will probably rise to take account of the new and proven risk of
successful hearing loss claims against you. Over succeeding years, the
insurance company will eventually get back more than the value of the original
award as, quite naturally, it needs to make a profit.

Leaving the decisions totally in the hands of the insurers displays a
somewhat relaxed attitude. Your company really needs its own test protocol, one
which will provide results that can be used to encourage the insurers either to
fight or settle. Such a protocol is suggested towards the end of this article.
It may be needed for a second reason. You will probably need help in the future
to refute claims by well-meaning medical practitioners that a particular
employee’s hearing loss was caused by noise exposure. To explain why, we must
discuss the 1989 UK Noise Regulations that are about to change.

The new noise regulations

Just when we had become used to the UK Noise Regulations, it is now almost
certain that they will be tightened as a result of more restrictive European
legislation to be adopted before the end of 2001. Tighter UK Noise Legislation
must then be enacted before the end of 2004 – which could mean as early as
2002, although a later date is more likely.

Full details of the likely form of the new legislation are available from
Scientifics – see the address at the end of this article – but in a nutshell, a
far higher number of employees than ever before will be included in the hearing
conservation programme and the permissible noise exposure limits will be lowered.
The current main second action level of a daily noise exposure of 90dB(A), for
example, will be reduced to 87dB(A) and employees will be able to demand
hearing protection at levels 5dB lower than is the case currently.

For a few months earlier this year it even appeared that the noise exposure
level at which employees could request hearing checks under the new directive
would be lowered by 5dB from its current daily noise exposure value of 85dB(A)
as specified in the original 1986 EEC directive, thus vastly expanding the
number of employees in the audiometric testing programme. However, the HSE
fought this proposal and the current 1986 value will be retained in the new

The alert reader may find this starting level of 85dB(A) difficult to
reconcile with the current higher starting levels for audiometry given in the
HSE 1995 guidance booklet Health Surveillance in Noisy Industries but this is
because the HSE advised UK Ministers that the 85dB(A) EEC obligation could be
met by referring to the NHS all employees exposed to this level who wanted an
annual screening test.

Surely this advice can only be valid in a parallel universe. When the new
regulations come into force it would be surprising if Brussels allowed the UK
to get away with that very suspect NHS ploy twice.

Of particular relevance here, however, is that the new directive does
contain interesting wording on the topic of audiometric results. If, on
testing, an employee is found to have an "identifiable" hearing loss,
a doctor, or a specialist if the doctor thinks it is necessary, shall assess
whether the damage is likely to have been due to exposure to noise at work. If
the loss is thought to be due to noise, then the doctor or other suitably
qualified person should inform the employee accordingly.

This raises the question of how the doctor or other specialist is going to
be able to decide if the loss is due to noise or not. A wrong decision will not
only affect the particular employee, but also trigger audiometry for other
employees thought to have been similarly exposed.

Obviously the HSE will need to write a new code of practice on audiometric
assessment, but this is not likely to happen swiftly, and in the meantime
companies and the medical profession will need some guidelines to assist in
such assessments.

To do this, a scientific method is needed whereby you can demonstrate the
legitimacy or otherwise of a noise-induced hearing loss claim, the same
conclusion with which we ended the last section.

Scientific proof

Fortunately, it is now possible to put scientific, numerical proof forward
against the expert who retreats behind the "in the light of my
experience" defence when asked for evidence to back up his claim that the
loss was caused by exposure to noise at work.

Epidemiological studies over the last few decades have allowed scientists to
link episodes of noise exposure quantitatively to the resultant hearing loss.
Using these results, you can assess how closely the measured hearing loss
matches the degree of noise to which the employee has been exposed. However, at
least two problems remain.

Firstly, some of the calculations required can be laborious and difficult to
apply mathematically by the uninitiated. Many conceptual traps also await the
unwary. Secondly, a variety of calculation formulae and methods exist, and
decisions need to be taken as to which to use, and which database of non-noise
exposed controls should be used.

One answer is to accept the help and guidance offered by a piece of software
known as NoiseCalculator. It enables non-specialists to perform the
sophisticated calculations and checks.

However, a third problem still remains. Linking noise exposure to a measured
hearing loss is complicated by the variability of the effect of noise upon
different people. Expose 10 employees to the same amount of noise, and 10
different noise-induced hearing losses will probably result.

So how do you link cause and effect? The answer is to adopt the same
procedure in the investigation as would be used by the courts in deciding upon
the outcome of the whole case. Here the major decision would be taken "on
the balance of probabilities", and it is possible to use the mathematics
of the chosen assessment method in the same way. Again, the software will help,
as indicated by the screenshot of the NoiseCalculator (Figure 1).

The crosses and circles represent the hearing acuity in the employee’s left
and right ears respectively. The upper and lower bounds of the grey area show
the hearing losses to be expected in the 25th and 75th percentile of the
population if exposed to the same amount of noise as the employee in question.
The white line bisecting the grey area shows the median expected loss, while
the lower dotted line represents the loss that the 10 per cent most susceptible
people in the population might sustain after the given noise exposure.

As can be seen, the hearing loss exhibited by the employee in question is
far worse than any of these percentile boundaries, meaning that it is highly
likely that some other damaging mechanism must be at work. This gives strong
grounds for the construction of a defence, and a justification to go to the
expense of funding a full clinical investigation of the employee concerned.

And what if you have no accurate noise exposure data for the employee? Well,
use a worst-case estimate. If the hearing loss of the employee greatly exceeds
that which is likely under worst-case conditions, then the case for the defence
is greatly improved. If you do not have any noise level measurements available
at all, then the programme will suggest typical levels in various occupations
for you.

Additionally, you can run a few worst-case scenarios predicting the possible
losses that an employee may have sustained in previous occupations. The programme
will divide responsibility for the currently observed hearing loss between all
the employers in the employee’s work history, according to the noise exposure
for which they were responsible.

This would give a legitimate reason for approaching the previous employers
to discuss the overall claim with a view to arriving at an agreement over a
joint out-of-court liability payment. It is more than likely that initially
they would reject such an approach, but sight of the calculations described may
change their minds.

What can you do immediately?

– Ramp up your hearing conservation programme

– Start audiometry as recommended by the HSE

– Use the most accurate form of audiometry available – the zigzag Bekesy

– Think of using an audiometer such as the CA850 shown that contains an
internal database, or link it to your computer or occupational health software
package so that you have sequential audiograms with which to both protect an
employee and form a defence

– Look at the way you are measuring noise – are you still measuring the
noise emitted by machines, or are you now able to measure the actual noise dose
experienced by an employee?

Noise measuring equipment has become less expensive and more sophisticated
over the last decade, as has hearing protection. Review what you are using –
any design changes which encourage employees to make full use of them all of
the time they are exposed to hazardous industrial noise are to be welcomed.
Earmuffs are available, for example, containing receivers which accept three
entertainment channels from an aerial strung around the factory walls, and a
new natural sound technology earplug has been launched with flatter attenuation
characteristics, permitting better reception of speech, and a more consistent
performance in differing noise environments around the plant.

The new noise regulations will force industry to concentrate even harder on
its efforts to eradicate noise at source, and it is worth looking regularly to
see what new advances may be available to make protecting the hearing in
industry easier.

Further information can be obtained from the author at SJK Scientifics,
Epsilon House, The University Research Park, Chilworth, Southampton SO1 7NS,
Tel: 023 8076 7954 or e-mail scientifics@FSBDial.co.uk

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