- In these seven cases each Claimant claims damages for personal injuries and consequential loss arising out of her or his employment in the textile industry in Nottinghamshire or Derbyshire. The claims are in respect of damage to hearing said to have been sustained by exposure to excessive noise. The cases are seven out of more than seven hundred that have been issued. Common to all the cases is the feature that exposure was at a noise level less than 90dB(A)lepd. The Defendants say that at common law there was no liability for exposure at such levels of noise. Liability, in respect of the period before its repeal on 1st January 1996, is also claimed under section 29 of the Factories Act 1961. In each case there is a dispute about whether the Claimant has suffered noise induced hearing loss at all, and it has been necessary to consider the approach to diagnosis, and the assessment of disability in cases where the noise exposure has been of the order of what is revealed in these cases.
- Claims for noise induced hearing loss are now well trodden ground for personal injury practitioners and courts, especially in areas where traditionally there has been a good deal of heavy manufacturing industry. The leading case of Thompson v Smiths Shiprepairers (North Shields) Limited [1984] 1 QB 405 established 1963 as the latest year after which employers could not hide behind ignorance of the effects of noise, and of the means to provide protection to employees. Mustill J in that case was not, however, concerned with levels of noise, because the noise to which the claimants in Thompson were exposed was plainly greatly in excess of 90dB(A)lepd. In some cases liability at common law has been established in respect of noise levels under 90dB(A), for example in the recent case of Harris v BRB (Residuary) Limited [2006] PIQR 10, CA. In these cases the Claimants mount a more general attack in principle on the idea that liability at common law requires exposure to noise of at least that level, and they say that liability attaches in cases of exposure from the 1960's in the whole bracket 80-90dB(A).
I will start by stating the basic facts and terminology, though that may seem superfluous to many practitioners, and have been more elegantly set out in other cases.
The nature of noise and its measurement.
- Noise is generated by pressure variations in the air. The frequency, or pitch, at which those variations occur is expressed in cycles per second, or Hertz: hz. Since the frequencies with which sound that is relevant to the human ear extend to several thousand Hertz, the unit of a thousand hz, or a kilohertz (khz), is often referred to. Noise may consist of a single frequency: pure tone. Most noise existing in one place at one time, however, is more complicated than that, and consists of simultaneous sounds at different frequencies: It is broadband sound. The doubling of the frequency of sound alters the pitch of the sound by one octave, so that 2khz is an octave higher than 1khz, as is 4khz than 2khz. Middle C is 261.63hz.
- The loudness of a noise depends on the sound pressure level of the energy that produces it. The sound pressure level is measured in decibels (dB). The decibel scale is logarithmic, so that each 3dB increase or decrease involves a doubling or halving of the sound energy. As discussed below, the human ear is more sensitive to noise at some frequencies than at others. For that reason a simple measurement of the overall sound pressure at one frequency is of limited usefulness. It is possible to measure the sound pressure level at different frequencies, so as to build up a picture of the quality of noise in a more useful way, typically at octave intervals or bands: as for example 500hZ, 1kHz, 2, 4 and 8kHz. The outcome of octave band analysis requires a degree of interpretation. In modern times (and with the use of measuring instruments that perform the necessary calculations automatically) the pressure level across a spectrum of frequencies is expressed as a single weighted figure. The different weighting systems run from A to D, but the A weighting is most commonly used as appropriate for general industrial noise. The weighting may be considered as a curve on a graph running across several octave bands, the centre of which representing the middle frequencies is higher than each end, the low and higher frequencies. This reflects the fact that sound in the middle frequencies has greater effect on the human ear than at low or high frequencies. The weighted measurement so obtained is described as dB(A). Sound pressure level does not equate to the level of noise as it is perceived by the hearer. A hearer will not perceive a doubled sound pressure level as involving much, if any, increase in sound. So 88 dB may not sound much louder than 85dB, though it involves twice the energy. For the hearer to think that one sound is twice as loud as another it may be that the sound has in fact to be about 10 times louder in terms of sound pressure level: for example a jump from 80 to 90 dB.
- Apart from very loud noise which itself is immediately damaging (and with which this case is not concerned) consideration of the damage that a person may have suffered to his or her hearing involves not only the level of noise, but also the length of time of exposure to it, since damage by noise depends on the overall dose of noise received The noise to which the human ear is exposed is not often constant, but fluctuates over any given period of time, as when a machine emitting noise is used intermittently. The averaged noise over a period of time is described as the equivalent continuous sound pressure level, designated as leq, so that someone might be exposed to 90dB(A) leq over a period, being exposed to different sound pressure levels at different times during the period. A commonly used unit of noise exposure is arrived at by measuring or calculating the dose of noise experienced during a working day of 8 hours. That sound level taken over an 8 hour day is described in dB(A) lepd, or the average daily noise exposure level. It is the same as dB(A) leq for 8 hours.
- Since damage to the ear by noise depends on the overall dose of noise received by the ear (that is, is a product of the level of noise and the period of exposure, so that 8 hours at 90dB(A) is equivalent to 4 hours at twice the level of noise, 93dB(A)) it is necessary to be able to calculate the amount of noise an individual has been exposed to over a period of years as the dose builds up. That long term dose is the Noise Immission Level (NIL). For a period of a year the NIL is equal to the daily dB(A) lepd. For further years the NIL is increased according to the formula 10log(years), and so, in terms of expression, builds up slowly: For example, a 20 year exposure at 85dB(A)lepd will result in a NIL of 98; the same period of exposure for 80dB(A)lepd, and 90dB(A)lepd yields NIL's of 93 and 103 respectively.
Noise and the human ear
- The outer ear funnels sounds towards the ear drum, by which the vibrations in the air are converted into mechanical vibrations. Those vibrations are conveyed by the middle ear to the cochlea. The cochlea analyses the sound (as for example into different frequencies); amplifies it; and translates those amplified and differentiated vibrations into nerve impulses which are transmitted to the brain by the auditory nerve, so producing the perception of sound.
Hair cells in the cochlea play a vital part in this process of translation into nerve impulses. Noise induced hearing loss involves by exposure to noise over time damage to the hairs which is permanent and irreversible.
- Hearing is measured by use of an audiogram, in which is recorded the threshold of hearing of pure tone sound at different frequencies. Expressed as a chart (it may also be expressed as a table) the result may look as follows:
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If measured by air conduction, earphones are used. Measurement up to about 4khz may also be by bone conduction by which is measured the reaction to vibration of bones in the skull. Bone conduction by passes the outer and middle ears, and attempts to measure the functioning of the cochlea directly. Noise induced hearing loss affecting the cochlea is described as sensorineural. It is to be contrasted with conductive hearing loss in which there is a decline in the function of the outer or middle ear. Such conductive hearing loss is not caused by the sort of noise levels with which this case is concerned, but may be caused by disease or infection, or by excess wax , or by very loud traumatic noise, or other causes. Audiometry as described above requires co-operation and effort and reliability in the person being tested. The measurement of hearing therefore involves techniques to assess consistency, but there is always a significant margin of possible error. It is possible to estimate hearing by cortical electrical response audiometry (CERA), in which changes in electrical activity in the brain in response to sound is measured . That method has not been used in any of these cases. As a cross check to the reliability of an audiogram produced by air or bone conduction a speech audiogram may be taken to give some assessment of the level of disability and whether it is consistent with the thresholds as revealed in an audiogram.
- The threshold levels applicable to individuals are often expressed as an average hearing loss (that is, an average of the number of dB by which the hearing thresholds exceed 0dB) taken over several frequencies. At different times different studies and bodies have proposed averaging different frequencies for this purpose. The main frequencies important to speech are 500hz to 4khz, though loss at 6khz has significance for high tone noise, for instance music or birdsong. As hearing thresholds increase the ability to interpret speech is progressively disabled. Threshold increases in the higher frequencies in that range tend to affect discrimination of consonants, and so may make speech indistinct without appearing to affect the overall loudness of the sound. Threshold increases in the lower frequencies are associated with vowels. Relevant threshold loss has been taken over .5, 1 and 2khz; 1, 2 and 4khz, 1, 2 and 3 khz, and other combinations. In England the most common method of averaging is over 1, 2 and 3 khz. It has the convenience of coinciding with the averages used by the DSS for disability benefit calculation. Some averages use the better ear only. The hearing in the better ear has a much greater effect on the overall level of disability than the worse ear. However, the DSS method is to average both ears in a way that gives some effect to the weaker ear: Take 4 times the average of the better ear; add the average of the worse ear, and divide the resulting figure by 5 to arrive at the overall hearing loss, or impairment. That overall loss may then be used as a tool to estimate the degree of disability resulting from the impairment constituted by the threshold hearing loss.
- This case is concerned with the risks to workers exposed to noise where the noise levels are between 80 and 90dB(A)lepd. As will be seen it is accepted that since 1963, or more clearly 1972, official guidance identified an unacceptable risk to hearing of workers exposed over 90dB(A)lepd, and common law liability for negligence has generally attached to employers whose employees suffered harm to their hearing through being exposed to noise at or above that level, though in some industries a later "date of knowledge" than 1963 has been arrived at in individual cases, and in others an earlier date; in a few cases also, liability has been imposed for exposure below 90dB(A). Since the present cases are concerned with exposure at such a lower level, it is necessary to set out the outlines of the evidence as it has developed about what the risks to workers are who are so exposed below 90dB(A)lepd. I will review the main features of that evidence as it has been presented in this case, then trace the history of official guidance and statutory regulation, and then deal with further material that the claimants say is relevant to what employers in the textile injury and these particular employers should have known at particular times
The risk to employees from exposure below 90dB(A) lepd
- The risk of noise induced hearing loss is assessed by reference to statistics applicable to different populations of people. The susceptibility of any individual to such loss is very variable and cannot be predicted, though serial audiometric examinations of the same person at regular intervals may pick up early signs of a decline in threshold levels and so suggest particular vulnerability. In addition to the variability in reaction to noise, the hearing of any person will deteriorate with age. Children and young people have hearing at higher frequencies than the usual scale up to 8khz measured by audiometry. Progressively, however, the threshold levels in those higher frequencies rises, and from the middle years of life that loss moves into lower frequencies and affects the frequencies in the conventional audiometric range of 8khz and below, including speech frequencies. This hearing loss of aging, known as presbyacusis, is also very variable as between individuals, and in an unpredictable way, though to some extent the pattern of loss through aging, when it begins to occur, may provide some information about how susceptible an individual is to presbyacusis. So two important ingredients for assessing the level of disability caused by noise: the susceptibility of the individual to damage, and the rate at which that individual's hearing thresholds would in any event decline with age, cannot be predicted. The statistics deal with a proportion of a particular population that it may be predicted will suffer a particular level of hearing loss by a particular time in their lives. These statistics are not applicable to an individual; though, in the absence of other evidence, they are in practice used to assess the proportion of a claimant's hearing loss that is to be attributed to noise and the proportion that is to be attributed to presbyacusis, and to compare the individual to what may be expected in a chosen population of people.
- In the 1960's research was carried out by a team led by Professor W Burns, Professor of Physiology in the University of London, and Dr D W Robinson, then Head of the acoustics section at the National Physical Laboratory into the effect of noise on employees in industry. Dr, later Professor, Robinson was to be a leading figure in this area until his death in the 1990's. The results of the research were published in 1970 by HMSO as "Hearing and Noise in Industry". The key conclusions were also presented to a multidisciplinary three day conference at the National Physical Laboratory in March 1970 given, as one of 19 papers, by Dr Robinson. The outcome of this work, as then published, was a proposal that it is possible to associate a particular noise exposure (arrived at by reference to time and noise level) with a statistical distribution of degree of impairment from noise in different percentiles of an exposed population. The resulting formula enables the construction of tables which can be referred to in order to enable the predicted effect of noise on a given exposed population to be looked up. In "Hearing and Noise in Industry" Burns and Robinson said in their summary:
Our results comprise the necessary material for a formal Code of Practice for the preservation of hearing in industry"
The authors proposed in the body of the text a limit of maximum exposure:
The limit can be set at a variety of levels according to the ultimate risk judged to be acceptable, and we suggest that it should not be set higher than 90dB(A) for a normal continuous daily exposure which is likely to persist for many years
- Tables were first published in 1973, but in a more conveniently useable form in 1977, as the NPL tables, by Robinson and Shipton. Although some of the figures have been subject to criticism and proposed amendment, the basic approach has endured. By the time the 1977 NPL tables were published BS 5330 : 1976 had been established, based on the same Burns and Robinson formula, as a method by which can be specified a relationship between noise exposure and the expected incidence of hearing disability. In the foreward it is provided:
Determination of a maximum tolerable noise exposure is outside the scope of this standard. It involves consideration of risk in relation to other factors. For occupational noise exposure such a limit is specified in the Department of Employment (HMSO1972) Code of Practice for reducing the Exposure of Employed Persons to Noise
ISO1999 in 1975, following a draft in 1971, also proposed a formula to be used as a predictive tool of risk to hearing from noise, but in a way unsuitable for tabulation. ISO1999 was substantially revised in 1982 and 1990, though the present ISO1999 is equivalent to the 1982 formula. Professor Lutman has extracted a small chart based on ISO 1999 (in its 1982 formula) to illustrate the effects of noise at various levels of exposure, in respect of predicted threshold loss at 4khz, the frequency most sensitive to noise:
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- ISO1999 did not in any of its versions purport to suggest limits to tolerable exposure. The 1975 version said that that was the province of:
Competent authorities who generally demand the institution of hearing conservation programmes if limits are exceeded. In many cases 85 to 90dB(A) equivalent continuous sound level has been chosen
In the mid 1980's Dr Robinson, now Research Professor in the University of Southampton, was asked to review the experimental data as it then stood about noise exposure and hearing. In a paper published in 1987 as an HSE Contract Research Report he looked at the data, and compared the existing standards, including BS5330 : 1976 and ISO 1999. The paper gave hearing threshold levels averaged over 1, 2 and 3 khz both for otologically normal populations and for typical unselected populations. The latter is generally thought to be a more appropriate starting point as being closer to representing a wider population than the highly screened (for features other than age and noise) otologically normal population, because the highly screened population will have better hearing. Tables from the report include Table 4.15, distributions for average hearing threshold levels at 1, 2 and 3 khz, and Table 4.16, percentages of people in those populations likely to exceed a 30dB threshold:
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- It can be seen that the noise levels go down in 5dB steps from 100 to 85. Below that is a table for non-noise exposed people which is useful for comparison purposes, because the people in the first part of the table have suffered hearing loss through the effect of age and noise combined.
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- There followed in 1988 tables for use in the same way that the NPL tables could be used, though for different populations, whereas the NPL tables were based on an otologically normal population, as was ISO7029 which gave predicted values for presbyacusis. The 1988 tables go down to 83db(A). In expanded tables published in 1991 there are tables for non noise exposed people, and the noise level for exposed populations start at 85dB(A). In his remarks on the tables Professor Robinson said:
There is some uncertainty as to the course of noise induced hearing loss below 85dB(A); it can only be said that lower noise levels would induce still smaller threshold shifts than the (already small) shifts associated with 85dB(A). Accordingly, no values are given for noise levels below 85dB(A).
In the previously published tables an extrapolation downwards to 83dB(A) was included, in the hope that this extension might enhance the usefulness of the tables. This extrapolation, when combined with the downward extrapolation of the percentile range to 5%, led to minor anomalies in the tables.
Professor Lutman said in evidence that Professor Robinson made a mathematical error in a formula used for his work in 1987, that related to the modelling of expected hearing loss. He was unable to say what difference that would have made if Professor Robinson had been aware of the error and corrected it. I did not understand from what Professor Lutman said that the error invalidated the general thrust of the conclusions or the resulting tables.
- In the 1980's the Medical Research Council National Study of Hearing provided information from a large database of tested people, and the results have been used in a number of studies in which tables of expected hearing loss appear: notably Davis: Hearing in Adults. In 1992 a working group comprising in the end King, Coles, Professor Lutman (the Claimants' expert in this case) and Professor Robinson published "Assessment of Hearing Disability. Guidelines for medico-legal practice" (The Black Book). The Black Book will have to be referred to later in other contexts. Here it can be noted that the table for products of excess noise level times exposure duration did not extend to sound levels lower than 85dB(A).
- In 1994 Robinson Lawton and Rice produced a research report for the Health and Safety Executive called "Occupational Hearing Loss from Low Level Noise". The impetus for commissioning the work came from a proposed EEC directive under which it was intended to extend regulatory control of noise from 85dB(A) to 80dB(A). The report was unable to present data based on an average of 1, 2 and 3dB, nor by reference to a threshold of disability, because of the very small threshold shifts involved. Instead the authors based their data on the 4khz frequency alone, which is the frequency most sensitive to noise. In the executive summary the authors say:
Curve fitting procedures applied to the noise-induced threshold shift, embracing both variation in noise level and years of exposure duration, indicate a negligible effect at 75dB(A). Above that level, but below 85dB(A), long term exposure to noise has some effect but the amount of noise induced threshold shift is so small as to be practically undetectable in individual cases and only measurable in a statistical sense. Moreover it is so small as to be overshadowed by the loss of hearing associated with advancing age, whether due to natural causes or the insults of daily living
The report makes clear that the data used for hearing loss caused by noise below 85dB(A) is not direct scientific data, but depends on extrapolation from the effects of noise on people exposed at higher levels:
Direct experimental evidence of noise induced hearing loss for exposure to noise below 85dB(A) is lacking from the published scientific literature. The approach adopted here was to assemble the best available data from reports and papers covering research over the last three decades, and from standardisation documents encapsulating the received opinion of experts. From these sources a composite relationship is derived between Lepd and the audiometric effect upon hearing, which is then extrapolated downwards to the noise levels of interest, below 85dB(A).
- The conclusion of the report was that a reduction in the action level from 85 to 80dB(A) would be virtually without reward in saved hearing. It is right to note, as will appear later, that the European Commission was unmoved by such arguments, and, probably with the intention of coming close to the goal of allowing all employees to avoid any risk of noise induced hearing loss at all, put in place a directive that has resulted from 6th April 2006 in the first level of regulatory control, (education and the provision of protection for those who wish to use it), being reduced from 85 to 80db(A)lepd.
- In 2000 Coles Lutman and Buffin published an article in Clinical Otolaryngology entitled "Guidelines on the Diagnosis of Noise induced Hearing Loss for Medico-Legal Purposes". The scheme proposed for diagnosis will have to be considered later, but for the present purpose explanatory notes 6 and 7 include the following:
Note 6. At face value [the formulae] predict that even the most extremely noise resistant percentiles would suffer some degree of NIHL. They also suggest that noise exposures of low level (e.g. low 80's in decibels) and duration (e.g. only a few years) would cause small but finite degrees of NIHL in some of those so exposed.
However, their original data sources were limited to cross-sectional studies, and the evidence for such effects is weak, being extrapolations from effects measured mostly in people with around average degrees of susceptibility and large amount of noise exposure. The earlier work also exaggerated the apparent effect of small noise exposures. Moreover epidemiological studies involving low level and/or short-duration and/or intermittent exposures…. seem to indicate an occurrence of less than the expected degree of hearing loss and in smaller proportions of those exposed.
These scientific considerations have to be judged also in relation to the legal criterion of balance of probabilities and to what can be regarded as a reasonably reliable single measurement in an individual ear. At 4khz this is considered to be about 10dB. According to international standard 1999 (1990) noise exposure at 90dB(A) for 10 years, which equates to a NIL value of 100dB(A) causes a median NIHL of 11dB at 4khz (and, incidentally, about 3.5dB in the 3khz average) Hence our use of the 100 dB(A) NIL [in the guidelines]
Note 7. Lepd noise levels below 85dB(A) in fact cause very little NIHL. With low noise levels the noise immission calculations tend to over estimate the potential auditory hazard. For example, a virtually safe noise level of 80dB(A) if heard for 20 years, would yield an apparently unsafe NIL of 93dB(A). Therefore it is recommended that lepd levels below 85dB(A) should not be taken into account in estimating total noise exposure.
- In 2000 Professor Lutman also published a short paper in Occupational Medicine, entitled "What is the risk of noise-induced hearing loss at 80, 85, 90dB(A) and above?"
He included 3 tables, one showing the expected threshold shifts at 4khz (the most sensitive frequency for noise damage) in 5% of men after a 45 year working lifetime:
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He concluded the article by saying:
From a preventive point of view, as long as daily noise exposures do not exceed 85dB(A), the risk of hearing loss is minimal
- Those notes to the 2000 paper may be a convenient introduction to the oral evidence about the risk of hearing loss by being exposed to noise below 90dB(A) and below 85dB(A). I deal with this area 85 to 80dB(A) separately because the evidence in the individual cases makes the area of 85-80dB(A) important, and because in the material about risk, and statutory regulation, 85dB(A) is an important feature. The risk from exposure moves, of course, in a continuum, though not in a straight line, and does not stop at any particular sound level, though there is agreement that there is effectively no risk below 80dB(A), despite the fact that the NPL tables would suggest there is. The result of some of the research material is set out above. 90db(A) is an arbitrary level, and approaching it from 85dB(A) the risk of noise induced hearing loss in some people is significant and increasing as 90dB(A) is approached. The risk going down from 85dB(A) was the subject of oral evidence.
- Professor Lutman said the NPL tables are less accurate below 90dB(A), though reasonably accurate above that level. They tend at the lower levels to exaggerate the effect of noise, partly because the assumption that was made was that the normal hearing of young people could be taken to be 0dB, whereas in fact the threshold is higher than that, so that the effects of age are underestimated. The figures yielded by the application of the ISO 1999 formula were not subject to the same criticism, and he stood by his opinion based on them that even at 80dB(A) there is a probability that most people will be affected, albeit the damage will be minor. Asked about the 2000 paper on diagnosis he said
The context of this is trying to make a diagnosis for individuals on the balance of probability. The difficulty that occurs is that for noise levels below 85 the expectation is that hearing losses will be very small. These are measurable in population terms, and hence pose a risk. But when it comes to identifying hearing losses in individuals, they are becoming very small for that context. Therefore these guidelines were recommending, particularly in the situation where somebody has been exposed to different noise levels for different employers, that it was a reasonable rule of thumb to simply discount the levels below 85 and focus on the others. I think there is a difference between trying to apply these sorts of statistics to individuals where a sort of larger hearing loss needs to be present in order to be certain or have the probability and populations where smaller hearing losses can be estimated.
When he returned to the witness box late in the case Professor Lutman discussed by reference to Professor Robinson's work the possible shape of the way in which hearing loss tapers off at low levels. It serves to emphasise his evidence that there is no clear cut off at 85dB:
Clearly if 85dB(A) causes some hearing loss and a much lower level causes no hearing loss, there must be some sort of transition between those two possibilities.
- Professor Lutman was, as shown above, careful in his description of the risks to hearing at exposures below 85dB(A). He could hardly be otherwise given what he had previously written. I have now mentioned his work and his evidence on a number of occasions. He was the expert witness for the Claimants dealing with a large range of matters. He is Professor of Audiology, Institute of Sound and Vibration Research in the University of Southampton. Mr Purchas QC has on a number of occasions both before and during the trial, and also in his final written submissions sought to confine Professor Lutman's evidence on the basis that he was giving evidence outside his area of expertise. It is quite plain that Professor Lutman's expertise is very wide ranging and that he works at the forefront of the development of understanding in various areas concerning audiology, including noise induced hearing loss. The number of papers to which he has contributed and which are referred to in the evidence in this case evidences his high standing in the firmament of audiology. The one area about which his opinion is not admissible is what
employers in industry should have done to discharge their duty to employees at different times, in the light of industry practice and understanding, even though it is an area about which he may have strong opinions. Nor, however, is anyone else's expert opinion admissible on that very question. The attack on Professor Lutman's expertise leaves the breadth of it unconfined.
- The doctors, Mr McCombe for the Claimants (together with Dr Rajput for one of the cases); and Dr Yeoh, Mr Jones and Mr Parker for the various Defendants, were really concerned with diagnosis and quantification of hearing loss in the individual cases. They had nothing in the way of scientific evidence to advance in the area of what degree of noise induced loss one might expect to see as the noise level ascended through the 80's. Mr McCombe said that he did not agree that there was no risk below 85dB(A). The evidence in that area may be statistical, but "this is all statistics". There will be very little hearing loss but it will still be there at low levels. Dr Yeoh thought that estimates of likely loss were based on tenuous scientific evidence below 85dB(A), and took the view that impairment caused by noise at such levels would be so slight as not to be identifiable. Mr Jones said that the evidence came from extrapolation from larger levels of noise (and despite Professor Lutman identifying papers in which low levels of noise were discussed, from the evidence produced to me, Mr Jones appears to be right). He said that the small changes involved were undetectable in an individual. They can't be detected on an audiogram. Mr Parker said that at low noise levels he suspected that the figures in the tables lacked power: The extent of risk below 85 is not known.
- Examples of the sort of threshold shifts due to noise that emerge from the various papers are given above. They differ, but often not by a great deal. If I have simply selected some that have come into evidence in this case, it is not to perform a task of deciding between them, which I could not do, but simply to illustrate in general the level of risk of hearing loss caused by exposure under 90 and 85dB(A). It is not possible to ignore the statements made by Professor Robinson, and in quite recent times by Professor Lutman about exposure below 85dB(A). What is plain is that the risk of identifiable hearing loss from noise at those levels is very low, and there is a degree of uncertainty about whether the figures are robust enough to translate into actual losses to be expected in individual people at all. On the other hand, to be sure that no noise induced hearing loss at all is caused in any individual, whether detectable or not, conservation measures would be required. Nonetheless, the description given to the risk to hearing of exposure below 85dB(A) by Professor Lutman in one of the publications set out above as "minimal" is one that I accept and adopt. Above 85dB(A) the risk accelerates up to 90db(A). In the high 80's given long enough exposure significant hearing loss may be expected in at least a substantial minority of individuals.
- The view I have reached has implications both for diagnosis of hearing loss in individual cases, and for breach of duty at exposure under 85dB(A). The identification of particular noise levels has no part in the way that the Claimants put their case. However Mr Hendy QC recognised that if the court came to a conclusion about the degree of hearing loss expected at such noise levels, it might express that conclusion first, thereby in effect confining the case on liability to noise levels of 85dB(A) and above. I do come to such a conclusion, so that in an area where the hearing loss to be expected can be regarded as marginal, or minimal, or so small as not to be identifiable in individuals but only in a statistical sense there could in my view be no liability at common law for breach of duty in exposing employees at such levels.
- I accept that assessment of actual risk as suggested by statistics at various noise levels is a separate question from what employers knew or ought to have known, to the extent that the common law required them to take action. If, however, the actual risk at any level was so small that no action was required of them, the fact that there may have been other information current at an earlier time which was inaccurate as to the extent of risk does not help, in my judgment, to establish liability.
The moves towards regulation
- The relevance of the information about risk at various times to the duty of employers depends on what they knew or ought to have known, and what they should have done with the actual or imputed knowledge. In addition to the developing knowledge just discussed, therefore, there are the moves towards statutory regulation, and various other publications that are in this case. I deal first with the moves towards statutory regulation, and the events that accompanied those moves.
A final report by a government appointed committee on the problem of noise under the chairmanship of Sir Alan Wilson was published in July 1963 entitled "Noise". The committee dealt with many different aspects of noise, particularly environmental noise, but Chapter Vlll dealt with occupational exposure to high levels of noise. They welcomed the fact that further research into the effects of noise had at that time been commissioned, but concluded that the then state of knowledge did not provide a firm enough basis for effective legislation.
- In the month before the publication of the Wilson Committee report, June 1963, the Factory Inspectorate published, as number 25 of a series of Safety Health and Welfare booklets, the first edition of Noise and the Worker. The preparation of the booklet had been prompted by the interim report of the Wilson Committee in March 1963. The purposes of the booklet were said to be:
To set out the basic facts, to suggest ways in which the working environment may be made less noisy, and the harmful effects of noise on workers be prevented or mitigated, and to indicate where further information and advice can be obtained
In deciding whether they have a noise problem employers are asked to consider 6 questions: the first is whether workers find it difficult to hear each other speak while at work in a noisy environment. The others are complaints, short and long term hearing loss, higher labour turnover, and management opinion that noise is affecting production. The booklet says:
If the answer to several of these questions is 'yes' there may be a problem of excessive noise. If so, efforts should be made to reduce it, or, if it can not be sufficiently reduced…. to reduce the exposure of workers to the noise, or to provide them with ear protection…
The booklet then discusses the measurement and danger levels of noise. The "A" weighting of noise had not then been developed, or at least was not in use, so that the levels of noise discussed are set out for different frequencies, grouped into octave bands. The result is more difficult to apply than an "A" weighted level. Under the heading "Danger levels of Noise", the booklet says:
Before the effects of loud noise can be judged.. it is necessary not only to measure the noise, but to assess the amount of exposure to it during a normal working day or working life.
Our knowledge of the relation of noise to hearing loss is as yet too limited for it to be possible to say with certainty what amount of exposure is safe- partly because people vary greatly in their susceptibility to noise. It is generally agreed however that if workers are exposed for eight hours a day, five days a week to a continuous steady noise of 85dB or more in any octave band in the speech range of frequency (500 to 4000 cycles per second) it is desirable to introduce a programme of noise reduction or hearing conservation (This is a level of noise in which normal speech cannot easily he heard at a distance of a few feet; communication can be achieved only by shouting) Frequency as well as intensity must be taken into account; high frequencies are more dangerous than low, at the same pressure level. As the following table shows, a sound pressure level of 80dB, for example, is not considered harmful at frequencies below 1200 cycles per second, but should be avoided at frequencies above that level
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(These values are said to equate to about 89 dB(A), though the comparison is not exact, and only works if the noise concerned matches the profile suggested in the table)
- Methods of noise control were then discussed: Reduction of noise at source; reduction of noise transmitted through air or structures; alteration in working arrangements; and hearing conservation by ear defenders, and periodic testing of workers' hearing, where the noise levels to which they are exposed are at or approaching the levels in the table. The purpose of the testing is to record any change in acuity, and to
Identify and move to other work individuals who are especially susceptible to noise and who may therefore be endangered by levels harmless to the majority
The booklet included a substantial bibliography of mainly technical sources.
- A second edition was published in June 1968. So far as it is material to employers' duties, it was really a second impression
The third edition was published in 1971, and went through several impressions. It was very soon overtaken in April 1972 by the Code of Practice for Reducing the Exposure of Employed persons to Noise. In the third edition of Noise and the Worker, "A" weighted sound levels are used, and the concept of leq is explained. The passage headed "The Danger Levels of Noise" contains the following:
THE DANGER LEVELS OF NOISE
Exposure to excessive noise causes deafness which may be severe if the exposure is continued for a long time. Because some people are more liable to hearing loss than others and because our knowledge of the effects of noise exposure, especially exposure to intensive noise of short duration, is still incomplete it is not possible to set out a simple table of permissible limits for all types of noise. It is, however, possible to give guidance which will help to protect most people against serious hearing loss.
Continuous and intermittent noise
When deciding whether continuous or intermittent noise is a hazard it is necessary to consider both the sound level and the number of hours of exposure per day. Unless efficient hearing protectors are worn people should not be exposed to levels of noise exceeding those set out in Table 1. For exposures of less than 15 minutes per day the permissible sound level can be increased by 3dBA for each successive halving of exposure duration, subject to an over-riding condition that no unprotected ear should ever be exposed to a sound pressure level of 135 dB or more.
| Exposure duration |
Maximum sound level |
| hours per day |
dBA |
| 8 |
90 |
| 4 |
93 |
| 2 |
96 |
| 1 |
99 |
| Half |
102 |
| Quarter |
105 |
Table 1 Levels of noise which indicate a serious hazard to hearing.
After a discussion of how to estimate a continuous equivalent sound level where noise levels fluctuate, there appears this passage:
Desirable Noise Levels
Damage risk criteria should be regarded as maximum permissible levels and not as desirable levels. If possible the noise should be reduced to levels lower than the danger levels set out in Table 1 to avoid the risk to the minority of people who are exceptionally susceptible to hearing damage, and for reasons of general welfare
- The 1972 Code of Practice was produced by a committee that included Professor Burns and Dr Robinson. The code sets out detailed requirements for controlling exposure to noise: Surveys, methods of control, ear protectors and training for their use, reduction of exposure duration, new machinery, training, and record keeping are covered. There are 9 appendices. Much of the first 4 sections are worth setting out here:
This Code of Practice deals with the engineering aspect of the reduction of noise exposure of employed persons. It does not include advice to machinery manufacturers, which will be covered separately or on the medical management of noise exposed personnel, or on the place of audiometry.
Section 1:
Scope of Code
1.1 General application
1.1.1 This Code of Practice applies to all persons employed in industry who are exposed to noise.
1.1.2 The Code sets out recommended limits to noise exposure. It should be noted that, on account of the large inherent variations of susceptibility between individuals, these limitations are not in themselves guaranteed to remove all risk of noise-induced hearing loss.
(1.2 Application to machinery)
(1.3 Relation to nuisance noise and vibration)
.
Section 2:
Objectives of code
2.1 Specification of limits
2.1.1 This Code specifies a limit for exposure to noise, and describes
methods of measurement (Appendices 1 and 2) which can be used to determine whether the limit is exceeded.
(2.1.2)
2.2 Reduction of sound levels
As a primary aim, the Code seeks the reduction of noise exposure to below the specified limit. As a secondary aim it seeks the reduction of sound levels generally.
2.2.1 The Code indicates appropriate measures for the reduction of noise exposure which should be taken by both management and employed persons.
Section 3:
Summary of measures to be taken
3.1 Measures to be taken by management
3.1.1 Management should accept a general responsibility for ensuring that the best practical means for noise reduction are applied.
3.1.2 The aim should be the general reduction of noise exposure. Where noise exposure less than the limits set in Section 4 are not achieved, ear protectors should be provided and their use ensured.
3.1.3 Appropriate staff should have adequate training in noise measurement and control.
3.1.4 Suitable records should be maintained.
Where it is not practical to ensure that the noise exposure is less than the limits set out in Section 4, and people must wear ear protectors, management should:
(a) identify and mark places where ear protectors are required.
(b) control entry into ear protection areas,
(c) ensure that suitable ear protectors are provided and are used,
(d) ensure that people provided with ear protectors are instructed in their care and use,
(e) where ear protectors are worn and the limit in Section 4 may still be exceeded at the wearer's ear, ensure that exposure periods are suitably reduced.
(3.2 Measures to be taken by employed persons)
Section 4: Limits
4.1 Desirable sound levels
4.1.1 The limits set out in this section should be regarded as maximum acceptable levels and not as desirable levels. Where it is reasonably practicable to do so it is desirable for the sound to be reduced to lower levels.
4.2 Limiting sound level
4.2.1 People should not be exposed to sound levels exceeding the limit set out in 4.3 to 4.5 below, unless they are using ear protectors which effectively reduce the sound level at the user's ear to or below the limits for unprotected ears. Note: The allowance for ear protectors, when worn, should be calculated as described in Appendices 4 and 5.
4.3 Continuous exposure
4.3.1 If exposure is continued for 8 hours in any one day, and is to a reasonably steady sound, the sound level should not exceed 90 dB(A).
4.4 Non-continuous exposure
4.4.1 If exposure is for a period other than 8 hours, or if the sound level is fluctuating, an equivalent continuous sound level (L ) may be calculated and this value should not exceed 90 dB(A).
4.5 Non-continuous exposure which cannot be adequately measured
4.5.1 4.64.5.1In certain circumstances, for example where employed persons
4.7move from one area to another, it may be difficult to measure and control exposure to non-continuous sound. If the non-continuous exposure cannot be adequately measured and controlled, any exposure at a sound level of 90 dB(A) or more should be regarded as exceeding the accepted limit and requiring the use of ear protectors. Places where this level is likely to be exceeded should be clearly identified (see Section 5).
Section 7:
Ear protectors
7.1 General
7.1.1 When the application of means of controlling sound at source, or restriction of exposure duration, does not reduce the noise exposure to below the limit set out in Section 4, employed persons should be supplied with effective ear protection on an individual basis
Appendix 3 to the Guide proposed a method, by reference to a nomogram, for working out an equivalent continuous sound level, or leq. Instruments later readily available that worked out the leq over a period of time had not then been developed, or at least not for a mass market. In setting out the periods of different sound in order to perform the calculation, the Appendix provides:
Periods of exposure at less than 85dB may be ignored
- The Code of Practice was widely circulated and referred to by factory inspectors. Although, as will appear, it was expected that regulation by legislation would follow it was not until January 1990 that such regulation was put in place. There were only 2 areas where there was statutory regulation: Regulation 44 of the Woodworking Machines Regulations 1974 required reduction of noise to the greatest extent reasonably practicable and provision and use of ear protection where people are likely to be exposed to noise at or above 90dB(A)leq (8 hour). The regulations provided that the dB(A)leq should be worked out in an approved way, and the way approved was the method provided for in the 1972 Code of Practice. The Agriculture (Tractor Cabs) Regulations 1974 provided that the noise level in a cab before a certificate of approval could be given for it should not exceed 90dB(A).
- Also in 1974 came the Health and Safety at Work Act 1974. Breach of the primary duty of employers under section 2(1) of the Act to ensure so far as reasonably practicable the health safety and welfare at work of all employees gives rise to criminal but not civil liability, but that section provided a route by which the Health and Safety Executive could and did compel employers to move towards observance of the 90dB(A)lepd limit specified in the 1972 Code of Practice.
- In 1975 the Health and Safety Executive published a report entitled "Framing Noise Legislation". The report was prepared by the Noise Sub Committee of the Industrial Health Advisory Committee whose membership included Professor Burns and Dr Robinson, as well as representatives from both sides of industry. The same committee with some of the same membership had been responsible for the 1972 Code of Practice. The committee recommended that regulations should be made under the 1974 Act, and set out the proposed framework. They regarded the 1972 Code of Practice as the model, and followed it closely in their recommendations, including a limit of 90dB(A)leq of noise to which employees could be exposed. The report discusses the equal energy principle, by then well established, and the fact that it was therefore possible to predict the risk of hearing damage from a lifetime's exposure. In discussion of the 90dB(A) limit the report says in paragraph 19:
19 The Code's noise limit of 90 dB(A) leq has widespread international acceptance, and although it does not eliminate all risk of hearing damage, we feel it continues to be the most practicable standard, in recognition of the necessity of concentrating limited resources on workers subject to the most significant risks and of eliminating these risks as a first priority. If the limit were lowered to 85 dB(A) for example, the Factory Inspectorate survey indicates that the total number exposed would be more than twice that at 90 dB(A) and above. Prediction of risks of hearing damage at these levels, based on a lifetime's exposure of 30 or 40 years,10 indicates that the proportion of an exposed population likely to suffer unacceptable degrees of impairment falls off rapidly below 90 dB(A). The specification of a daily dose introduces a further margin of safety since it is unlikely that a large number of workers would receive the full daily limit throughout their entire working lifetime. Similar conclusions have been reached in other major industrial countries, and none of those examined in our survey has introduced a generally applicable environmental limit lower than 90 dB(A)l'. Nevertheless, the question of a lower limit should be reconsidered at regular intervals. A level of 90 dB(A) is by no means ideal, and the aim should be to ensure a progressive reduction.
The industrial background at that time as discussed in the report included an estimate that between half and one million workers in manufacturing industry were exposed to noise over 90dB(A)lepd.
- In 1978 the Health and Safety Executive produced a discussion document "Audiometry in Industry" and in 1981 2 important documents. There was a consultative document entitled "Protection of Hearing at Work" and a background document to the consultative document entitled "Some Aspects of Noise and Hearing Loss". The background document set out the current understanding of noise induced hearing loss in detail, but the same information was contained in both papers about the relationship between reduction of noise levels over time and the incidence of serious hearing loss. The relevant part of the consultation document is as follows:
Risk of hearing loss due to noise
1 The risk of hearing loss is related to the level of noise exposure and the length of time a person is exposed to that level. Information on how noise affects hearing and on the scales of resulting handicap is given in reference 1. The evidence on hearing loss due to noise at work is complicated because hearing loss may also occur from other causes such as age, accident and illness.
2 Taking these difficulties into account, Fig 1 can be used to obtain an estimate of the risk of hearing loss (expressed as a percentage of persons exceeding a stated hearing loss) for a given level of noise exposure. Curves are drawn for exposure periods of 10 years and a lifetime, and for two different levels of hearing loss (30dB and 50dB).
The information given in Fig 1 may be represented in tabular form as Table 1
Number of persons in every 100 likely to suffer 50dB hearing loss
| Level of exposure (dB(A) Leq,(g nrj) years'exposure |
Lifetime exposure/ |
10 |
| 100 |
32 |
17 |
| 90 |
11 |
5 |
| 80 |
3 |
1 |
If, for example, a population of 100 persons were exposed to a noise level of 100dB(A) Leq (8 hr)for a lifetime, about 32 of them would be expected to suffer a 50dB hearing loss. If, on the other hand, 100 persons were exposed to a noise level of 90dB(A) Leq (8 hr) for a lifetime, then about 11 of them will suffer a 50dB hearing loss. Thus, by reducing the noise level from 100 to 90dB, the risk of hearing loss is reduced by 21 persons in a hundred. If the same exercise is repeated for a noise level exposure of 80dB(A) Leq (8 hr)for a lifetime, about 3 persons out of 100 will suffer a 50dB hearing loss. The reduction in risk of potential hearing loss at this level compared to the 90dB(A) Leq (8 hr) level is about 8 persons in every 100 persons exposed.
3 In other words, reduction of the level from 100 to 90dB(A) achieves a 'saving' of 21 persons in every 100 and reduction from 90 to 80dB(A) achieves a further 'saving' of 8 persons in every 100. Similar calculations can be made for different levels, exposure durations and degrees of hearing loss.
4 It is clear from these figures that the degree of reduction of risk achieved by reducing the level from 100 to 90dB(A) is much greater than that achieved by reducing it from 90 to 80dB(A) and that the maximum benefit in terms of protection of hearing will be gained by directing the major effort at noise control towards those exposed above 90dB(A) Leq (8hr). Nevertheless, it is clear that there is still a risk, albeit less, at levels below 90dB(A) Leq (8 hr) and this merits appropriate action where it is reasonablv practicable.
3
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The above tables and graphs do not give figures or a line for a non-noise exposed population, so they do not illustrate the effects of noise alone on a population, simply the relative effects of different levels of noise over time.
- The proposal in the paper was that the major effort should be directed at eliminating noise exposure over 90dB(A), while recognising the risk to some employees below that level. Under the heading "Proposed new legislation" the document includes:
[The Health and Safety Commission] has sought a solution in which priority in use of resources is given to those areas where risk is greatest and where expenditure of resources is given to those areas where risk is greater and where expenditure of resources will bring the greatest benefit in reduction of the number of workers suffering loss
In considering the target that ought to be set for efforts at noise reduction, it is clear that, in the light of evidence of risk below 90dB(A)leq (8 hr) those responsible for noise reduction ought not to be relieved of all duties at levels below this. However, it is also clear that more effort should be required above this level than below it
The outline draft regulations attached to the consultation document provided that no person should be exposed above 90dB(A)lepd, but that without prejudice to that limit there would be a duty to reduce exposure at levels below 90 if reasonably practicable. The effect of the proposals about noise levels did not, therefore, depart substantially from the provisions of the 1972 Code of Practice 9 years earlier.
- Before the consultation process was complete the European Commission on the 18th October 1982 published a draft proposal for a Council directive on the protection of workers from the risks related to exposure to noise. This draft directive, if carried into effect, would have compelled member states to legislate to set a maximum daily sound exposure level to which the ear of a worker is subjected at work at 85dB(A)lepd. The draft directive also provided for audiometric testing for those who had to wear protection in order to comply with the 85dB(A)lepd limit. These proposals from the Commission prompted vigorous debate, in which employers' organisations and unions took part. On the one side the CBI and employers sought to uphold 90dB(A) and on the other some unions supported the Commission, and others still argued for 80dB(A)lepd. The nature of the argument is captured in a debate in the House of Commons on 7th December 1983. After representations made from other countries in Europe as well as this country, the Commission in June 1984 withdrew their draft with a view to replacing it. It was replaced by less stringent proposals and led to the Noise at Work Directive of 12th May 1986. The exposure limit is to be 90db(A)lepd, but where the exposure is likely to exceed 85dB(A)lepd ear protectors were to be made available, together with information and, where relevant, training about potential risks and the wearing of hearing protection, and the opportunity for medical tests. The resulting legislation was to be brought into force by 1st January 1990. The recitals to the directive make it clear that the Commission had it in mind that the directive was an interim measure, and that it was likely to return to the subject to achieve lower noise levels still:
Whereas the current situation in the Member States does not make it possible to fix a noise exposure value below which there is no longer any risk to workers' hearing.
….whereas this Directive contains provisions which will be reviewed in the light of experience and developments in scientific and technical knowledge in this field
- After the directive there came in 1987 an HSE consultation paper "Prevention of damage to hearing from noise at work; Draft proposals for regulation and guidance". The framework of regulation was bound to be as set out in the 1986 directive, unless the UK government were minded to derogate from the obligation, which they were not. The draft guidance to employers, in its commentary on the proposed regulation 6, a general duty to expose exposure of employees to noise to the lowest level reasonably practicable, includes this passage:
In practical terms this requirement means that… the employer will need to consider whether it is reasonably practicable to do more to control the noise level, perhaps in the longer term, to reduce any risk to hearing below [90dB(A)lepd]. There is a quantifiable risk of hearing damage from exposures between 85 and 90dB(A), and a residual though small risk below 85dB(A)
That statement in due course was to find its way into the guidance actually promulgated, and in independent publications in the early 1990's, for example the IRS Guide to the Noise at Work Regulations.
- The 1986 Directive was carried in to effect by the Noise at Work Regulations 1989 which came into effect on the 1st January 1990. The First Action Level (85dB(A)lepd) and the Second Action level (90dB(A)lepd) were established in accordance with the Directive. Where noise exposure is likely to exceed 85dB(A)lepd a noise assessment has to be made, and records kept. In addition to the specific duties related to the action levels, there is a general duty under regulation 6 to reduce the risk of damage from exposure to noise to the lowest level reasonably practicable. The HSE Guide introducing the Regulations made clear, as appears from regulation 6 itself, that there was no cut off point, and that the general obligation applied below 85dB(A)lepd:
There is a quantifiable risk of hearing damage from exposures between 85 and 90dB(A) and a residual though small risk below 85dB(A), so in practical terms this means that in addition to the specific steps required by the Regulations, the employer will need to consider whether it is reasonably practicable to do more to control the noise level, perhaps in the longer term, to reduce any risk to hearing from exposures below [90db(A)lepd]
Regulation 11 provides for adequate information, instruction and training to be given to employees where exposure at 85dB(A)lepd is likely.
- In the early 1990's the Commission returned to its wish for lower levels than the 1986 Directive had provided for. Ultimately the Noise at Work Directive of 6th February 2003 appeared, brought into effect by the Control of Noise at Work Regulations 2005, which came into force on 6th April 2006. The aim of the regulations, as appears from regulation 3(1), is to protect persons against risk to their health and safety from exposure to noise at work. In addition to the general duty to see that risk from exposure is eliminated at source or reduced to as low a level as is reasonably practicable, there is to be no exposure above 87dB(A)lepd; Steps are to be taken to reduce exposure so far as practicable above 85dB(A)lepd; where there is likely exposure over 85dB(A)lepd, hearing protection must be provided. Where there is likely exposure over 80dB(A)lepd hearing protectors must be made available on request. Suitable information instruction and training must be provided where 80dB(A)lepd is likely to be exceeded. These regulations, at the end of the development of guidance that started in 1963, if they are obeyed, enable an employee to avoid any risk of damage to his hearing from noise.
Other material mentioned in the pleadings
- The other material, mentioned in the pleadings, are the work of Mrs Jean Stone in the 1970's, and the HATRA report of 1976. In the 1970's Mrs Jean Stone, a noise control and hearing conservation consultant carried out surveys for the National Union of Hosiery and Knitwear Workers. The First report was published in June 1971 and re-printed in March 1972. It is entitled "Investigation into The Effects of Industrial Noise on the Hearing of Employees in the Hosiery Industry". Tests were carried out on 87 employees, of whom she found that 55 had hearing impairment attributable to noise exposure, 23 had normal hearing, and 9 were rejected from analysis. She measured simple dB(A) levels for a number of different machines, and found significant hearing loss in workers who had been exposed to machine noise at between 80 and 90dB(A) as well as over that level.
In her second report in 1974 Mrs Stone noted, with reference to the 1972 Code of Practice, that a level of 90dB(A)lepd was too high to give adequate protection to some industrial workers She described the Code as "an important first step" and said:
It is to be hoped… that the 90dB(A) level will not come to be regarded as the ultimate objective in noise control and hearing conservation"
In her third report in December 1976 she re-visited some of the persons tested in the first survey, and found that the hearing of those who in the meantime had not worn ear protection had become significantly worse than those who had. She found by interview that even slight hearing loss had an adverse effect on home and social life; that a hearing conservation programme could be effective in preventing hearing loss; and that audiometry could be carried out satisfactorily.
Jean Stone's work was limited, but the feature of it particularly pointed to by the Claimants is the confirmation by her that some workers exposed to noise levels between 80 and 90dB(A) could be expected to suffer hearing loss in consequence and that a properly run hearing conservation programme could be effective.
- How wide a circulation these reports had is not clear, but her work was referenced in the HATRA Research Report number 43 in 1976, entitled "Noise in the Knitting Industry" by G.M. Coles. HATRA was an industry research body based in Nottingham. Coles took 905 measurements of noise in 57 factories. The reference in this case to the measurements have been largely by Mr Hill, engineer for the Claimants, as evidence going to the question what noise individuals were exposed to. However, the methodology of Mr Coles is not fully explained in the report. It seems clear that the meter used did not give a leq figure, but that Mr Coles recorded the noise made by each machine when running. From the point of view of an employer in the knitting industry in the late 1970's and 1980's looking through the report, the effect would be to reveal the very wide variation in noise emitted by machines of various types, and in some circumstances by machines of the same type. In the context of the time it would be likely for many employers to point the need for a noise survey, depending what area of the industry they were working in, and whether there was an indication of noise levels over 90dB(A).
Other documents and publications
- In their written submissions the Claimants refer to a number of other documents that are in or referred to in the papers that add, it is said, to the body of information in the public domain and which might have informed the state of knowledge of individual employers:
(i) The sources referred to in a paper entitled "Industrial Deafness, A review of the information available to the ordinary reasonable and prudent employer prior to 1972", by W I Acton.
(ii)
(iii) A textbook by Professor Burns in 1968: "Noise and Man" in which were indicated expected threshold shifts at 4khz after a lifetime exposure to sound levels at 82, 80, 79 and 78 dB.
(iv) An article by Dr H P Stout published in March 1970 for the Textile Research Associations. It contains a passage which is relied on as the sort of statement, current in the literature, alerting the reader to a risk to hearing below 90dB(A):
(v) The noise level above which damage to hearing becomes important on continuous pressure during a normal working week is not known with certainty… but it is probably somewhere in 80-90dB(A) region for moderate frequencies. The higher the actual noise level is above the critical level the more the effect is likely to be on the operative's hearing, and certainly levels over 95dB(A) must be regarded as hazardous.
The survey of typical noise levels includes some in the spinning and weaving industries, where noise levels were often much higher than 90dB(A). In discussing the noise levels, at another passage in the article Dr Stout says:
Of the machines examined, cards, Co-We-Knit and bobbinet lace types run at noise levels of 85dB(A) or less. These may be considered as safe from a hearing point of view…
(vi) The proceedings of the Teddington Conference at the National Physical Laboratory in March 1970, at which Dr Robinson gave his paper explaining the equal energy principle and the establishment of formulae that enabled levels of hearing loss as a result of exposure to noise to be predicted in exposed populations. Bryan and Tempest also gave a paper entitled "Noise damage liability- evidence as to the state of knowledge". The conference was attended by representatives of Courtaulds.; also present was Mr Bramer, Courtaulds' expert engineer witness in this case. The Claimants' case is that by this time, 1970,
The reasonable and prudent employer will have known at this point of his ability to estimate the risk of noise damage at various levels of exposure to his working population
(vii) A paper by the British Occupational Hygiene Society published in July 1971: "Hygiene Standard for Wide Band Noise". The sub-committee responsible for this paper was chaired by Dr D E Hickish who was also at that time on the committee that produced the 1972 Guidelines. The aim of the paper was to establish a damage-risk criterion: to state what in the opinion of the committee is an acceptable degree of exposure to noise by reference to the number of people who can be expected to suffer handicap, according to their definition of a 40 dB threshold averages over .5 to 6khz), as a result. The proposed standard was expressed as follows:
A noise immission of 105dB is acceptable exposure on the basis that no more than 1 per cent of exposed persons will experience handicap due to noise after lifetime exposure. The equivalent continuous noise level which corresponds to this immission is 90dB(A) for a working lifetime of 30 years.
The paper makes it clear that if a noise immission level of 105dB is the acceptable limit, it might be reached by longer exposure at lower noise levels than 90dB(A):
The acceptable durations in years for various noise levels are:
| Leq Equivalent-continuous Noise level dB(A) |
Acceptable duration of exposure in years |
| 88 |
50 |
| 88.5 |
45 |
| 89 |
40 |
| 89.6 |
35 |
| 90 |
30 |
(viii) The 1973 NPL tables. No copy of these is available. They set out in tabular form the results of the Burns and Robinson work, but apparently in a form not as convenient to use as the 1977 Tables. The extent of their circulation during their short life of 4 years in unknown.
(ix)
(x) The 1977 NPL Tables. These have remained. The Claimants say that anyone using them would have found significant levels of hearing loss predicted in populations exposed for as little as 10 years at 80dB(A) and above. The fact that subsequent research has shown that the degree of hearing loss in fact suffered at such levels is less than the tables predict does not, it is said, detract from the importance of the tables as alerting employers to the existence of risk.
(xi)
(xii) An editorial in the Lancet in 1979, which discusses the declared aim of the TUC to have the acceptable level of noise exposure reduced to 80dB
(xiii) Health and Safety Recommendations published in 1982 by the Knitting Dyeing and Lace Industries' Joint Health and Safety Committee. In Appendix 2 is set out a table of exposure limits. The bottom 2 entries in the table are:
| Noise level |
Daily exposure limit |
Typical noise emissions And effects |
| |
|
|
| 90 |
8 hours |
Rapier, air and water jet Looms. Heavy motor lorries |
| 80 |
|
Recognised "acceptable" level in Britain- still deafens 18% of all workers. Hearing damage begins at this level. Typical of very busy traffic |
The general approach to noise in industry
- The state of understanding of the individual employers involved in this case will be looked at below. There was evidence given by the expert witness engineers for Courtaulds (Mr Bramer and Mr Currie) about the approach to control of noise in the period from the 1970's in industry. The report of Mr Worthington for Pretty Polly and Guy Warwick is also in evidence. To Mr Bramer, the guidance in Noise and the Worker and the 1972 Guidelines provided a "clear and consistent recommendation to employers as to how they ought to deal with noise in the workplace". The result was that in his practice, his invariable advice until the late 1980's, was that "the relevant level was a daily personal noise exposure of 90dB(A)". This approach, he said, was standard during the period up to 1989 among noise professionals, and taught at training courses. In the mid 1980's, when it appeared that EEC regulation would involve a first action level of 85dB(A) his advice changed to reflect that. He was not aware of the NPL tables before the 1980's when he found that they were being used by medical experts writing reports for the purpose of deafness claims. He has never come across them being used in any part of industry. In evidence Mr Bramer said that he gave advice to employers in terms of complying with the 1972 Code. He was speaking to the 90dB(A) level, as were all his colleagues. He agreed that the advice would be to answer the question "Tell us how to comply with legislation and the Code of Practice", rather than "Tell me how to avoid reasonably foreseeable risk to my workforce". He would have recommended 90dB(A) as the cut off point, but would also have said "that does not actually stop some more susceptible people from having some small noise induced hearing loss". If asked about risk, he would have had some difficulty, and regarded the question as more one for medical people.
- Mr Currie said that the Health and Safety Executive and factory inspectors after the 1974 Act concentrated their advice and enforcement on the 90dB(A) level. He was not aware of any instance in which the NPL tables had been used by employers to predict the level of risk for their workforce. In evidence Mr Currie said that good practice won't necessarily remove all risk. He agreed that there has been no very different understanding about noise induced hearing loss since the 1970's. The first thing to look at when deciding on practices, which is what employers have to do, is to look at the guidance available.
Mr Worthington's report is to the effect that employers looked to the 90dB(A) limit in the Code of Practice as the maximum acceptable limit, and that the Factory Inspectorate and HSE did not refer employers to the risks below that limit as risks about which they should take action. That was the practice of the day, and employers taking advice, if they did, would be referred to the standard in the Code as being what had to be observed.
- It is clear from some of the documents referred to above that by the beginning of the 1980's there were still many people employed in industry exposed over 90dB(A)lepd, and that the approach of enforcement agencies was to concentrate on those people. The evidence of the engineers referred to above suggests that that was a common approach until at least into the mid 1980's. That the 90dB(A)lepd level was regarded, as is the effect of the evidence of the engineers referred to above, in industry as the touchstone of reasonable standards that should be attained is evidenced by notes published by the Wolfson Unit for Noise and Vibration Control in the University of Southampton in 1976. The notes were intended to supplement a series of seminars held round the country in the Autumn of that year entitled "Industrial Noise- The Conduct of the Reasonable and Prudent Employer". The seminars were intended "primarily for company lawyers, solicitors, insurance claims and risk assessors, safety officers, medical officers and others with interests in occupational hearing loss". The notes are therefore strong evidence of the prevailing advice being given to people in industry concerned with noise at that time. They describe the 1972 Guidelines as establishing a comprehensive "damage risk criterion" based on 90dB(A)lepd; and that they have been actively promulgated by the Factory Inspectorate. In the discussion of the emerging principles of legal liability for noise induced hearing loss the authors say:
Over the last fifteen years knowledge as to the relationship between noise and deafness has grown and become more precise….Today a reasonable employer ought to know that to expose an employee to noise in excess of 90dB(A) for eight hours or its equivalent is potentially hazardous. It also seems a fair assumption that the reasonable employer should have known of the criteria set out in "Noise in Factories" and "Noise and the Worker" by the mid 1960's"
The individual Defendants
- The particular way in which the individual Defendants were addressing the question of noise has been the subject of evidence. Some possible witnesses for each were not called, and Pretty Polly decided to call none of their lay witness evidence, having served more than 15 statements. That has prompted the Claimants to submit that the court should draw adverse inferences as discussed in particular by Brooke LJ in Wisniewski v Central Manchester Health Authority (1998) 1st April, CA. I think that the drawing of an adverse inference from failure to call available evidence always starts from the proposition that there must always be a "case to answer" before failure to adduce available evidence can be used to strengthen the opposing case. Here, I think that the limits of that approach go no further than this, that where disclosure or other evidence may justify a conclusion, the absence of evidence given from the witness box means that there is no challenge to the drawing of that conclusion.
Courtaulds
- Both Julie Baxter and Tony Parkes worked for Meridian Limited. Meridian was a subsidiary company of Courtaulds PLC. Julie Baxter was there from 1979 to 1989, and Tony Parkes from 1968 to 1988. Both worked at the factory at Belvedere Street at Mansfield. Courtaulds was a large company, operating in six divisions. It was at one time a FTSE 30 company. Up to the early 1980's there were over 100,000 employees. By the end of the 1980's the numbers were down to 48,000, with about 20,000 in textiles. The years covered by these claims reflected the position in the clothing and textiles industry generally, as shown by the other Defendants: Years of prosperity and expansion accompanied by takeovers and consolidation, followed in the 1980's by decline as worldwide competition took its toll. That competition by the end of the 1990's lead to the almost total demise of the industry in the United Kingdom, and the closure of all the factories with which these cases are concerned.
- The main evidence for Courtaulds was given by Dr Peter Cooper, because co-ordination of the need for a better management of noise control in the Consumer Products Group, the division of Courtaulds that included clothing manufacture, fell to him in the 1980's. He said that it was in the early 1980's that the issue of noise in industry began to be widely discussed. He was not involved with noise until the end of 1982, when he was asked to form and chair what became known as the "Noise Committee". There is no direct evidence of what happened before that time. There were divisions of the company where there were high noise levels, such as spinning and weaving, and Dr Cooper said that he was aware that hearing protection was provided. There were, by 1983, claims for damages for industrial deafness coming through, and some 200 were expected to be pending by the end of 1983. One difficulty in defending them was that there had not been the systematic noise surveys that the 1972 Guidelines required. At the time that the Noise Committee was set up, the European Commission's proposal for a directive limiting noise as received by the ear of an employee to 85dB(A)lepd was current. Dr Cooper obtained information that Courtaulds Research Division had assembled about noise. There were library facilities at Coventry. What publications there were is not now known in detail. The Courtaulds disclosure comes largely from Dr Cooper himself, who preserved his own files relating to his work chairing the Noise Committee. In the first half of 1983 a memorandum was circulated widely in Courtaulds PLC from Mr Dillon-Weston, a solicitor in the legal department, and Dr Lyle, assistant Chief medical officer. It drew attention to the increase in claims, the necessity of hearing protection over 90dB(A) in all circumstances, and contains these passages:
It has been suggested that some impairment may be caused by noise levels in the range of 85-90dB(A)…. We strongly recommend that hearing protectors be provided for all those who may be exposed to noise within the range 85-90dB(A)Leq
- The noise committee met first on 17th March 1983. Amongst the material that Dr Cooper had had by then was a paper on noise circulated by Mr Crosdale, Senior Personnel Manager at Courtaulds Apparel, indicating that a number of other countries had set the maximum exposure level, or an availability of protection level, at 85dB(A). The committee set the various companies in the division the task of carrying out proper surveys of noise levels at all the factories. That process took about a year to complete. By the March 1984 meeting in nearly all factories areas over 90dB(A) and between 85 and 90dB(A) had been identified. The policy was to mark and achieve compliance in the compulsory over 90dB(A) areas, and then to designate 85-90dB(A) areas as recommended areas for protection. The 90dB(A) action was immediate. The 85-90 areas were
Rather more medium term and it was suggested that a 75% acceptance of hearing protection in recommended areas should be the aim for mid 1985
- At a further meeting on 3rd October 1984 the 85-89 bracket was discussed at length, and the possible difficulties of attaining compliance in that area without Code of Practice backing, but a target of 80% compliance by the end of 1985 was to be aimed for. 100% compliance in compulsory areas had not yet been achieved. There was a recognition at this time, as is certainly the case, that information instruction and encouragement had to accompany the provision of ear protection. By the meeting of 12th March 1986 the EEC directive for first and second action levels had appeared, and the committee noted that their policies complied with the directive.
The above references indicate that by 1984 in the Courtaulds Consumer Products Group companies there was a policy or intended policy of making hearing protection available to employees exposed in the 85-90dB(A) range, and that the need for information and encouragement was also recognised. There were other activities, as appears in the documents, and explained by Dr Cooper in evidence, including the steps taken to reduce noise at source by modifying in some cases individual machines. In evidence Dr Cooper accepted that the drivers for the activity from the early 1980's were proposed legislation, and the rising incidence of claims. There was no assessment of the risk to hearing caused by different levels of noise. Dr Cooper, however, understood that there would be some people exposed below 90dB(A)leq who would suffer damage.
- Concurrently with the beginning of Dr Cooper's involvement in early 1983 Courtaulds was active in the debate stimulated by the 1981 consultation and the EEC draft directive. There is an index of correspondence, the correspondence itself apparently being no longer extant, showing a considerable level of activity. Courtaulds made written representations on 25th February 1983 against the proposed compulsory limit of 85dB(A). There were 57, 000UK employees, of whom 5000 were exposed over 90dB(A) and 12,000 to 85dB(A) and above. Courtaulds accepted the need to reduce the level below 90dB(A) where reasonably practicable "at least where there is a significant risk of hearing impairment", but made a case against a compulsory 85dB(A) limit, which was what the EEC then proposed, on economic and competition grounds. The wearing of hearing protection below 90dB(A) was said to be "increasingly burdensome, and very difficult to enforce"; it would also, it was estimated, cost several hundred thousand pounds a year.
- Mr Brian Arthurs gave evidence. His career was spent as a design engineer with Courtaulds research. From the early 1980's he had the important function of carrying out noise surveys, and gained expertise in that area. Some of his surveys will be referred to in the evidence about individual cases. He was, however, cross examined about the material with which he had in the past been familiar. There were two filing cabinets with documents to which he could refer. He said that he could not remember individual documents (apart from the 1972 Guidelines, which he had) but when they were put to him he had, or thought he had, a recollection of seeing the Jean Stone reports and the HATRA report. In general, things like that would be dealt with by the medical department.
Mr Allen Jones gave evidence about the history. He, however, did not join the textiles division as group safety advisor until 1987. I do not regard him as adding to the general picture given in particular by Dr Cooper.
- There is no doubt that Courtaulds PLC had the resources to look beyond the 1972 Guidelines and reach their own conclusion about the nature and extent of the risks posed to the hearing of their employees exposed below 90dB(A). I do not draw any direct inference about knowledge from the fact that Dr Hugh Dennis Jones or someone else from the medical department was not called to give evidence. Dr Lyle in any event lent his name to the 1983 memorandum, together with the solicitor Mr Dillon-Weston. I think it is the fact that nobody actually considered, asked or sought to answer the question "What are the actual risks to members of the workforce exposed to different levels of noise?". The 90dB(A) standard from 1972 was considered to be the standard that the law and good practice required. There was a clear awareness by the early 1980's that exposure to levels of noise between 85 and 90dB(A) could be expected to damage the hearing of some workers to the extent that action was desirable at those levels. No large company who responded to the consultation document or read the background document and was aware of the EEC proposals in 1982, and one that then took part in the debates trying to fend off compulsory protection at 85dB(A) on economic grounds, but not on grounds that such levels of exposure were not harmful, could be said to be ignorant of the facts by the beginning of 1983 at the latest.
Taymil Limited
- Taymil Limited is responsible for the liabilities of a number of companies that became subsidiaries of Coats Viyella PLC from 1986. There are three claimants who worked for such companies. Stephanie Baker worked at a factory at Huthwaite Road, Sutton in Ashfield, from 1971 to 2001. Her employers were Simpson Wright & Lowe Limited, hosiery manufacturers, who by the early 1970's became a subsidiary company of the Nottingham Manufacturing Company PLC. Nottingham Manufacturing Company, which had a number of other subsidiaries that do not come into this case, merged with Vantona Viyella PLC in 1985, and the resulting entity became a subsidiary of Coats Viyella PLC in 1986. For the last few years of Mrs Baker's employment her employer was Coats Viyella Clothing Hosiery.
- Christine Faulkner worked as a lockstitch machinist at a factory at Botany Avenue, Mansfield from 1973 to 1988. This was a making up factory. The factory belonged to Mansfield Hosiery Mills, which was a subsidiary of the Nottingham Manufacturing Company, and which was therefore taken over by Coats from 1985. Nottingham Manufacturing Company were therefore responsible for the operations at Botany Avenue in the 1970's and up to the second half of the 1980's.
Sarah Moss had a number of different periods of employment and employers. She worked during various periods between 1963 and 1994 mainly at the Botany Avenue factory, but also in later years at factories operated under the umbrella of Nottingham Manufacturing Company or Coats at Ollerton and Alfreton. Nottingham Manufacturing Company had over 12,000 employees in the 1970's and 1980's. Coats Viyella was a large group with 68,000 employees in the late 1980's, working in various divisions, but serious decline was already setting in.
- There is very little disclosure of documents from Nottingham Manufacturing Company (or, for that matter, from Coats). Apart from the documents disclosed, which are noise surveys for different factories and a report from Midland Insurance in 1983 relating to Huthwaite Road, the oral evidence suggests that the only other document that may have come the way of Nottingham Manufacturing Company or its subsidiaries is the 1972 Code of Practice. There was oral evidence from Mr Douglas Watson, who from 1974 to 1988 was the group insurance and risk manager; from Mr Frederick Gage, the group works engineer from 1973 to 1989; Mr Mike Hallows, the Ollerton manager from 1970 to 1974, and who had worked at Botany Avenue, mostly in management, from the 1960's; and Mr Ivan Jones, from 1974 until 1986 the Nottingham Manufacturing personnel manager.
- The factories in the group seem to have run largely independently, with factory management being responsible for health and safety, reflecting the origins of each factory in a separate business. There was no central health and safety function. Mr Jones said that he thought that in 1977 or thereabouts a Health and Safety policy document had been produced. He said it would probably have been destroyed "when the company folded". There is no reason to think that such a policy, if it did in fact exist, would on noise have done anything but refer to the limit of 90dB(A). The knitting shops were recognised as being the areas with possibly dangerous levels of noise, not making up areas. Of the documents referred to the first is a noise survey and accompanying documents done for Huthwaite Avenue by Midland Insurance in June 1983. Mr Watson had discussed the conclusions of it with Midland Insurance, as appears on the face of the document, though he said in evidence that he could not remember it. The survey refers to the 90dB(A) limit and suggests that all areas in the survey above 87dB(A) should be areas where ear protection is worn until the noise is reduced by engineering methods. A number of areas were identified as having noise over that level. Proper training and instruction of staff is advised; and appended is a guide to preparing a noise control policy, in which it is suggested that any noise reduction programme should aim at reducing noise to 84dB(A) or less if practicable. There is a noise survey of Botany Avenue by Mr Graham Allin, an engineer working to Mr Gage in August 1984 in which Mr Allin refers to company policy taking 85dB(A) as the exposure threshold level. I am satisfied that there was no such policy. Mr Gage, who was a good witness was quite clear about that, and explained how Mr Allin may have got that idea from Mr Gage's view about a margin of safety below 90dB(A) so as to ensure the 90dB(A) level was achieved. Moreover, in a draft survey of the Ollerton factory written after June 1984 when the EEC proposals were changed there is no mention of such a policy. The quality of their evidence was not as good as that of Mr Gage, but both Mr Watson and Mr Ivan Jones said that the limit to be worked to was 90dB(A). There is no evidence of any steps towards protection being taken in the Nottingham Manufacturing years aimed at conservation over 85dB(A). Mr Watson said in evidence that he was aware of the EEC proposal in 1982 to reduce the exposure level to 85dB(A). He was aware of the existence of the debate about that proposal, from discussions with insurers: "It was viewed with some scepticism, I think". Coats was a large organisation. By the time they came on the scene attention, if any, must have been focused on the EEC proposals that lead to the 1989 regulations.
- There is therefore no evidence that anyone in Nottingham Manufacturing or its subsidiaries with which this case is concerned turned their mind towards the level of risk about possible harm below 90dB(A)leq, except that Mr Watson was aware after 1982 of a debate going on about what levels would ultimately be imposed, and by the summer of 1984 it was known that though the compulsory level would remain at 90, some measures, possibly audiometry, would be imposed at 85dB(A). The 1983 Midland Insurance document is an important document, with its plain implication that the 90dB(A) Code of Practice level did not provide protection to everyone, and that a noise conservation policy should do better, but it does not provide the information that means that management at Nottingham Manufacturing were in a position of knowledge and understanding that set them apart from what I take to be the understanding of the great majority of employers, that 90dB(A)lepd was the official limit that had to be worked to. I do not think it is shown that Nottingham Manufacturing had a greater than average degree of knowledge.
Pretty Polly
- Margaret Grabowski worked for Pretty Polly as an overlocker from 1966 to 1970; 1973 to 1975; and from 1978 to 1997. Pretty Polly was always a subsidiary of other companies during these periods: Thomas Tilling Limited until 1982; Then BTR PLC until 1994; then Sara Lee UK Holdings Limited. In its heyday in the early 1980's the company had about 1500 production employees. The BTR Group at that time had over 42,000 employees.
- Pretty Polly served a number of witness statements, but in the event called no factual evidence at the trial. They made substantial disclosure. The general documents disclosed include the final Wilson Committee Report of 1963; Noise and the Worker (1968); the 1972 Code of Practice; the second, 1974, Jean Stone report, though there is evidence from correspondence that in 1982 they had at least three of the reports; the HSC 1981 consultative document; the HSE 1987 consultative document with the draft 1989 regulations. The internal documents include a Guide to Preparing a Noise Control Policy from Midland Insurance, undated but probably from the late 1970's or early 1980's, in which it is said that an exposure to 90dB(A)lepd over a long period there is a possibility of damage to hearing, so that adequate steps should be taken to prevent this; also that a noise reduction programme should aim at reducing noise to 84dB(A) or less if practicable; a Commercial Union Risk Management Limited paper from 1977 saying "research has shown that few industrial workers will suffer serious hearing loss if the intensity and duration of exposure is controlled to allow a maximum [of 90db(A)" and later "the exposure standard of [90dB(A) lepd] is based on the prediction that not more than 1% of those exposed to this level over a 30 year working lifetime will suffer social handicap as a result.
Levels should thus be reduced whenever possible and 90dB(A) regarded as a ceiling rather than a safe level".
- There is a memorandum, from the works study department in about December 1982, probably written by Mr Butler who later became manager of that department, for the production manager at No 3 factory, Sutton in Ashfield, but which seems to have had quite a wide circulation, in which it was said that 90dB(A) was the maximum level, and noise at that level involved accepting a certain risk of hearing damage.
If we as a company feel that we require a zero risk of hearing damage for our employees, then no person should be exposed to a noise level of more than 80dB(A) for a 8 hour day.
There followed a table of percentage risk of hearing damage (such damage was not defined) which showed 0% at 80dB(A), and at 85dB(A) 1, 3, 5, 6, 7, 8, 9, and 10% for 5, 10, 15, 20, 25, 30, 35, and 40 years of exposure respectively. The percentages for the same periods at 90dB(A) were said to be 4, 10, 14, 16, 16, 18, 20, and 21%.
- In 1985 there was "An assessment of Occupational Noise exposure at Pretty Polly" from John Butler, distributed to management. It contained the same table, so far as material, as the 1982 memorandum. In the conclusion Mr Butler said that with the exception of the Wepamat Straightening machines all machinery areas in the company were in excess of 85dB(A):
Even at this level we are accepting a certain risk of damage for our employees. If a zero risk of hearing damage is required, then no employee should be exposed to a noise level of more than 80dB(A) for more than 8 hours a day.
Thereafter in the late 1980's the documents are concerned with the forthcoming standards in the Noise at Work Regulations, and meeting the requirements of those regulations. Mr Butler, though he made a statement, was not called, so it is not clear where he got his information about low level exposure from and when. Some, but not all of it, is in the 1981 consultative document.
- There is no evidence that anyone at Pretty Polly turned their mind towards any evaluation of the risks below 90dB(A) before 1982. It is not really likely that they did so. It is plain from Mr Butler's documents that by that year he had done so. Indeed, it is unlikely that a company of that size where there had been some collection of materials, and where they cannot have been unaware of the EEC proposals and the very public debate that followed, could not have known that there was a real case to be made that exposure below 90dB(A) could cause levels of hearing damage that should be guarded against. I would put actual awareness of the nature of the real risk below 90dB(A), as with Courtaulds, as having arisen by the beginning of 1983.
Guy Warwick Limited
- Joan Hooley was employed by Guy Warwick Limited from 1978 until it ceased to operate in December 1992. The company had been formed as a result of a management buy out in 1977, so Mrs Hooley worked for the company for substantially the whole of its life. By comparison with the other Defendants they were a very small company, engaged in making up operations, principally suits and trousers. They had at their height four factories, all in Nottinghamshire, at Bilsthorpe, Blidworth, Newark and Walesby, and something under 400 employees. The company went into liquidation and operations ceased in December 1992. Mrs Hooley worked almost exclusively at the Bilsthorpe factory, in the press area.
- Although I heard evidence from Mrs Hole, personnel officer, and Mr Michael Kettle, chief engineer, that evidence was principally about noise in the factory. There is no evidence that anyone at Guy Warwick knew about the 1972 Code of Practice, or even about the Noise at Work Regulations 1989, which were in force for the last 2 years of the company's life. Mr Kettle was involved in health and safety and set up the health and safety committee. There were committee meetings at which he said in his statement the question of noise was never raised. The factory inspectors who came round periodically and the insurance representatives never raised it. No surveys were ever done. "In my opinion" said Mr Kettle, "the industry was not renowned for excessive noise". Whether, on the facts of actual noise to which Mrs Hooley was exposed, Guy Warwick were in breach of any duty to her, has to be judged on the basis that they had no actual knowledge of the relevance of noise to their operation.
Duty and breach of duty at Common Law
- The Claimants' case is that from at least 1963 employers in the position of the employers in these cases, in discharge of their general employer's duty of care, should have made available to the workforce hearing protection and appropriate information, training and instruction, where there was any real risk of damage to hearing by long exposure to noise. It is not their case that in the context of the industry with which these cases are concerned, it was reasonably practicable generally to reduce the levels of noise at source below the levels that actually existed. They say that those steps of providing hearing protection should have been taken at all levels of noise above 80dB(A)lepd, which is a level at which they accept that professional opinion is that there is no risk, and therefore that identifying particular levels of noise above 80dB(A) is unnecessary and irrelevant. I have already found that there was no material risk against which an employer should have guarded below 85dB(A)lepd, for the reasons given above. That means that the Claimants' common law case is concentrated in the area 85 to 89dB(A)lepd. At 90dB(A)lepd and above, with which this case is not concerned, employers of any kind would not be likely to escape liability for exposure, probably from 1963 and certainly from 1972.
- The Claimants draw a distinction between the existence of a duty of care and breach of it. They are right to do that, since the general duty of care undoubtedly existed, though breach depends upon what employers knew or ought to have known of the risk and the action they should have taken in the light of their knowledge, so the distinction does not seem to me to help greatly in the answer to the question "What should they have done?".
- Their case is that the effect of the documents and publications referred to above is that no reasonable and prudent employer could be unaware of a risk to a significant, though small, population exposed to levels below 90dB(A)lepd and take steps to afford their employees protection. The equal energy principle was made explicit by 1970; the 1972 Guidelines themselves made it plain that 90dB(A)lepd was not to be regarded as a safe level of exposure; as the 1970's went on, with the appearance of ISO1999 in 1975 and BS5330 in 1976, the case on the public documents alone gets even stronger. To set the legal framework of their case about what should have been done, the Claimants cite a hallowed text in this area of the law, the passage in Stokes v Guest Keen and Nettlefolds [1968] 1 WLR 1776 at 1783, about general industrial practice and developing knowledge:
From these authorities I deduce the principles, that the overall test is still the conduct of the reasonable and prudent employer, taking positive thought for the safety of his workers in the light of what he knows or ought to know; where there is a recognised and general practice which has been followed for a substantial period in similar circumstances without mishap, he is entitled to follow it, unless in the light of common sense or newer knowledge it is clearly bad; but, where there is developing knowledge, he must keep reasonably abreast of it and not be too slow to apply it; and where he has in fact greater than average knowledge of the risks, he may be thereby obliged to take more than the average or standard precautions. He must weigh up the risk in terms of the likelihood of injury occurring and the potential consequences if it does; and he must balance against this the probable effectiveness of the precautions that can be taken to meet it and the expense and inconvenience they involve. If he is found to have fallen below the standard to be properly expected of a reasonable and prudent employer in these respects, he is negligent.
Keeping reasonably abreast of developing knowledge and not being too slow to apply it would, it is submitted, have caused an employer to identify the risk to the hearing of employees under 90dB(A), and to take steps to provide protection. The risk that they would have to identify need not be a high risk: A number of authorities were cited in support of this proposition including: Bolton v Stone [1951] AC 850, HL; and the two Armstrong v British Coal Corporation cases in the Court of Appeal, in each of which Judge LJ gave the leading judgment: [1997] 8 Med LR 259, CA and (1998) 31st July, CA.
- The Claimants also cite passages from Mustill J's judgment in Thompson. It is necessary, in my view, to be careful when transferring things said in the shipyard cases to these present cases. In the shipyard cases the fact that workers were deafened by noise in the course of their work was known to everyone. The question was, by what date should employers have found out that effective hearing protection was available and taken steps to provide it. The important passage in Thompson set out below and cited by the Claimants must be read in that context:
From what date would a reasonable employer, with proper but not extraordinary solicitude for the welfare of his workers, have identified the problem of excessive noise in his yard, recognised that it was capable of solution, found a possible solution, weighed up the potential advantages and disadvantages of that solution, decided to adopt it, acquired a supply of the protectors, set in train the programme of educat