Bussey v Anglia Heating Limited [2018] EWCA Civ 243 – Impact Note

In our feature article, we provide an ‘Impact Note’ on Bussey v Anglia Heating Limited [2018] EWCA Civ 243, the Court of Appeal decision which we examined in last week’s edition of BC Disease News (here). The ruling was in relation to breach of duty in a mesothelioma claim.


Not much. However if it was as simple as from 1965 respirators must be provided, it would have been a short and straightforward Judgment.

From Rupert Jackson LJ, giving the lead Judgment of the Court of Appeal we can decipher:


…on the facts of that case:

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In undertaking a mixed finding of fact and law, Aiken LJ was right to consider and attach weight to TDN13. However, in Jackson LJ’s view, he may have gone a little too far.


Where HHJ Yelton may have fallen into error is treating TDN13, as the sole determinative factor:

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Had Maguire and Jeromson been cited to Aiken LJ then in Jackson LJ’s view, Aiken LJ would have looked at a wider range of issues to determining the standard of a reasonable employer.

It is clear that our asbestos tools are able to calculate that ‘bright line’.

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Assessing liability is not as clear as being above or below a 2 fibre/ml 4 hour TWA, but in training to clients and our solicitors, we have never presented it that way. What does seem clear from Jackson LJ is that exposure when measured against Occupational Hygiene levels is a factor, it is just not determinative of negligence on its own:

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Other factors need to be considered:

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Jackson LJ requires a more ‘nuanced approach’:

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So what would that more nuanced approach look like? We would suggest the following as a starting point:

  1. Exposure level when compared to the maximum permissible occupational hygiene level. That exposure is well below such a level is a factor (see below as to our comments on back calculations/back-guestimations)
  2. Other available industry guidance and medical literature
  3. The opinion of experts in the case as to what was available to a reasonable employer and what reasonable employers were doing at the period of exposure
  4. What could have been done to reduce exposures


It is clear that Underhill LJ is not in favour of back calculations, believing them to be ‘unsound’:

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This presents some problem, as this is routinely how liability is assessed. However these findings are against the backdrop of the agreed expert evidence that it was not possible to measure the actual level of exposure at the time of Mr Bussey’s employment:

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If you are unable to assess the fibre/ml exposure level, then obviously it is not acceptable to assume the risk to be acceptable. The more appropriate course would be to assume the worst, as advocated in Jeromson. Some commentators have suggested Underhill LJ’s may be adopted on a wider scale with the role of engineers being questionable.

However what about when you can calculate the fibre/ml exposure? Surely then the amount generated by the activity is a factor to which considerations of risk must be attached? The truth of the matter is that once an employer is capable of assessing the fibre/ml exposure in factual circumstances, then the back calculation becomes a viable consideration, as the Court needs to know what level of exposure would have been found, had the employer measured it, to give weight to that point. If this was not the case, TDN13 would not have been found to hold any significance. It was, just not determinative of the whole issue.

In a great many incidences government guidance was that environmental testing was not required, as HM Factories Inspectorate had taken on this responsibility for employers.

See TDN42, which was relied upon by HHJ Yelton to determine Mr Bussey’s likely exposure, though would not have been available to Anglia Heating, at the time of exposure:

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If the Court is again to considered lower exposure cases, it is assumed that the extent of exposure will be pretty low. In those factual circumstances, is it unreasonable for an employer to not undertake their own testing and place reliance on the figures within TDN42? That was the very purpose of the document:

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Even if capable of undertaking testing, if literature is available to advise an employer on likely exposure levels to their employees, should they be required to have undertaken their own testing and evidentially prejudiced by a failure to evidence testing results? In our view the comments of Underhill LJ should be viewed against the factual back drop and agreed expert evidence in Bussey that testing could not be undertaken and that none was. There is much litigation to come about the position when testing could be undertaken and whether it was reasonable, in light of other industry guidance available to the reasonable employer, to have done so.


The accepted position in Bussey was that it was not possible for Anglia Heating to have tested the fibre/ml generation in 1965-68. We would not accept that as correct. Testing was possible in 1963:

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And in 1968 testing was undertaken using both midget impinger and membrane filter methods:

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The famous Harries paper was published in 1971, but was a result of testing undertaken in 1967 and when setting out the sampling method, it is clear he used methods that had been endorsed from around 1963:

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We do not say fibre/ml testing would not be expensive and that it was readily available and whether such testing could reasonably be undertaken would depend on the size of the Defendant and its resources. Such testing was in its infancy and the accuracy of those methods may now be doubted. However if we are looking to a nuanced approach and what an employer could have ascertained at the time, then the results of such testing must be a factor, though not determinative.

However it cannot be said that testing was not possible in the 1960’s and as time advanced, that testing became cheaper and more readily available. Defendants will rarely be able to establish testing was undertaken, but the passage of time should not be used to make findings of fact that such testing was not undertaken. We simply will not know in the majority of cases. Literature was available to employers to inform them as to fibre/ml generation and risk and it is appropriate that they react to the level of risk perceived within. The Leathart & Sanderson paper from 1963 quoted above was published in the Annals of Occupational Medicine, the same as the Thompson & Newhouse paper in 1965, which forms the ‘watershed of knowledge’, though admittedly the Sunday Times did not pick up and publicise its findings.

Claimants will no doubt give evidence that no testing was undertaken in their presence. This may give the presumption that testing was not undertaken. Claimants may also look to Keefe v Isle of Man Steamship [2012] EWCA that the Defendants must be in breach of duty, as they can adduce no positive evidence of testing. To that we would say, the position where a Defendant can no longer adduce evidence as to whether testing was done, due to the passage of time, is no evidence that none was ever undertaken and Keefe can be distinguished on a similar basis to it was in Heavey v TMD Friction (Lawtel Document No. AC0139095) in respect of noise readings that could no longer be located:

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Testing may or may not have been undertaken. But if it had, what would it likely have revealed? This can only be done with the assistance of expert evidence. If TDN13 and other historical OH levels remain relevant, if not determinative on their own, then the Claimant still has a burden of proving a level of exposure that can be measured against those levels. They may not be required to prove exposure necessarily in excess of TDN13, but they will need to establish exposure at a level that would be of concern to employers, having regard to historical knowledge of the time.

If a case were to reach the High Court, it is envisaged it would be with expert evidence that readings would have been below the relevant OH levels, if located, then it seems unlikely the Claimant would derive much evidential advantage from their absence, assuming the quality of the Defendants expert evidence is strong.

As such, if we accept that Bussey does not remove Factories Inspectorate fibre/ml levels as a factor to be considered by an employer (though not the sole factor), then ‘back calculation’ seems to have a place from the mid to late 1960’s as a relevant guide for a Trial Judge on what is an acceptable response to risk. If TDN13 remains relevant, then the Claimants exposure when measured against it must also be relevant and this can only be obtained by a back calculation. 



It is clear that medical literature and industry guidance will have to be considered, alongside exposure against permitted limits (where assessment was possible):

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As well as allowing BC Legal clients to assess exposure against industry guidance figures, ABC asbestos has a full and evolving back of industry guidance for assessing what a reasonable employer could have ascertained when assessing risk:

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Consider a small dissolved construction company in 1975 that has its employees using hand tools to cut asbestos cement on site and outdoors. We do not now know if TLV calculation was undertaken, but it was possible with back calculation. D argued that it was entitled to rely on TDN42 figures from government, as its actual work with asbestos was very limited. C would spend 30 mins per day on the activity:

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This work, applying a 4 hour TWA is 25% of TDN13. Not determinative of an employer’s liability, but a factor for them to consider. If the Factories Inspectorate attended their premises and got these readings, then there is no way there would be any chance of prosecution.

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Applying a more nuanced approach, the employer would then have to look at the other literature available on working with asbestos cement with hand tools. So an employer goes to the Asbestos Research Council (ARC) a body set up (albeit by asbestos manufacturers) to assist the industry with the management of risk. This guidance is quite clear that ‘Work can be carried out quite safely on asbestos cement materials with power drills, hand saws and other hand tools’:

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And it that employer went to the ARC paper on ‘Control and Safety’ for working with asbestos sheets, what would he be told? That no precautions were required:

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In light of this guidance, specific to the task being undertaken by this employee, can an employer be negligent for determining that no precautions were required?


The case has been remitted back to the High Court for further determination by HHJ Yelton, as he has heard the relevant expert evidence:

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Experts therefore have a key role to play on what the literature would have told employers, what fibre/ml levels would have been found if tested and what a reasonable employer was doing at the point in time of exposure. It is clear that experts will still have a key role to play in determining the approach of a reasonable employer to risk:

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The ABC Asbestos Tool has an evolving data base of expert reports from previous cases which can be word searched to identify the likely expert evidence, relevant to similar facts as the case you face. The database currently has 70+ reports and is constantly growing:

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Given the Judgment in Bussey, it is clear the Court of Appeal are reluctant to set broad guidance on the law of negligence, beyond the statement that it is not determined by a simple mathematical calculation. Each case will turn on its facts and Williams was just one such example, as were all the other cases that followed that decision:

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Bussey sets no real test and cases going forward will be assessed on the facts, on expert evidence and with TLV level as a factor, if not the determinative factor.


Jackson LJ stated that it is not possible to remove the risk altogether. The risk remains once precautions have been taken is the ‘acceptable risk’:

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The Claimants representatives would have had the law that everyone encountering asbestos from 1965 should be wearing a respirator. Jackson LJ does not go that far, but the reading of Paragraph 43 above does not sit well with industry guidance in the 1970’s, which indicates scenarios where asbestos is used and precautions are not required that would factor into his ‘nuanced approach’. We would refer back to our example of working with asbestos cement and hand tools.

The precautions available to Anglia Heating by HHJ Yelton were to work outside or wear a respirator. Does outdoor working represent appropriate reaction to risk? Do we have a higher duty of care between October 1965 and TDN13 than after the publication of TDN13?


Underhill and Moylan LJ are perhaps more critical of the Defendants approach to risk. Much of that criticism stems from their starting position that by 1965 the knowledge of mesothelioma being caused by small amounts of asbestos was well known:

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This all flows from the Thompson & Newhouse paper and ‘Killer Dust’ article in the Sunday Times in 1965. This article did reveal the dangers posed by small levels of asbestos. However if we are adopting a nuanced approach to the consideration of risk, we need to consider the perception of risk by individual fibre types.  In 1960 Wagner identified that those working in a crocidolite mine were contracting mesothelioma. It is certainly arguable that the Thompson & Newhouse paper did nothing to dissuade that theory, as in each case where the type of asbestos encountered could be identified, crocidolite was present, albeit on occasions with other fibre types:

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Anyone experienced in examining historic responses to the 1965 article will have seen companies of the belief that the risk from asbestos were predominantly linked to the use of crocidolite asbestos. Indeed the 1966 Factories Inspectors Report identifies that all the evidence of risk from chrysotile indicate that is that it is less dangerous:

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There was some support for this being the belief in 1968:

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In 1968, the Ministry of Labour were advocating the substitution of crocidolite for amosite or chrysotile and it must be right that an employer would approach the risk from each fibre differently. Is the substitution of crocidolite with chrysotile an appropriate precaution as the Ministry of Labour suggest:

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Adopting a ‘nuanced approach’ to risk and assessing what a reasonable employer would have thought as to the risk would require an assessment of the fibre type used in the process as an employer’s response to crocidolite exposure after 1965 would be different where it can be established that only chrysotile was used. Bussey identifies chrysotile and amosite fibre types (Paragraph 11) and there was no finding of crocidolite exposure, though it is not clear whether the arguments around risk perception per fibre type was ever explored in Bussey. Certainly no mention of such arguments was made in oral argument in the Court of Appeal. Adopting Ministry of Labour guidance in 1968, cited above, the move from crocidolite to amosite or crocidolite might have been considered an acceptable precaution to meet the risk.

The BC Legal ABC Asbestos Tool allows you as it first stage of breach of duty analysis to make a decision on the most likely form of asbestos used in the operation, with reference to over 500 data sources:

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A respirator may be required for an appropriate response to crocidolite, but perhaps not in the case of white asbestos? An adoption of such a ‘nuanced approach’ encourages the Court to examine such matters and perhaps the law in respect of risk may be considerably differently in respect of chrysotile than of other fibre types?

Hawkes v Warmex [2018] EWHC 205 gives some insight into a ‘nuanced approach’. Expert evidence was heard, a back calculation had been undertaken and there was detailed literature as to the asbestos content of the task. We will leave to one side the interpretation of Factories Act and Asbestos Regulations 1931 in that case, which are controversial. Bussey concerned only the common law and how a reasonable employer might approach a known risk and this is what the Trial Judge sought to do in Hawkes. Exposure took place between 1946 and 1952 where obviously the fibre/ml level could not be tested. This informed the decision that no safe level could be assumed:

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Where no testing could be undertaken, then it seems even a nuanced approach would not allow an employer to work on the basis of a safe level:

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Hawkes provides only obiter statements, as ultimately the Court did not find exposure to asbestos. It is also of limited application as to any tension between Jeromson and Williams, given the Court of Appeal have now decided on the issue. However Bussey and Hawkes are consistent that there is no tension between those two decisions. Hawkes concerned work in an asbestos textile environment, where the risks from asbestos were first noticed and prompted the 1931 Regulations, albeit Hawkes concerns work with asbestos textiles, rather than the production of such textiles. Adopting the nuanced approach advocated by Jackson LJ is likely to have presented a similar outcome on common law duty, given the literature available to the Defendant, in that case and the very known dangers of working with asbestos textiles and the number of deaths seen in that industry. 


Cases where no testing was possible and where no precautions were taken, will be very difficult to defend indeed. An employer has to assume the worst. However the more the risk could be measured and understood, the more a nuanced approach might present a differing reaction to precautions.

The Court of Appeal refused to give real guidance where fibre/ml exposure can be realistically calculated and decided that Williams, Jeromson and Maguire sit happily together, as each case is correctly decided, relevant to its own facts.

Each subsequent case must therefore be decided on its own facts. One things that is clear is that TDN13 and other Government documents on TLV’s cannot determine liability on their own, but they remain a relevant factor, where technology existed to test fibre/ml exposure levels.

First instance Courts must adopt a ‘nuanced approach’ to the assessment of the foreseeability of risk in any given factual scenario and in doing so, they will have regard to the following:

  1. The TLV level
  2. Industry guidance as to the risk of the activity
  3. The asbestos fibre type
  4. Medical literature as to the risk of the activity
  5. Practical precautions that could have lowered the risk to the employee
  6. Expert evidence will inform several of the above

After Williams we saw a spate of cases decided for Defendants based on TDN13 and supporting documents. It is crucial that insurers consider carefully the next cases to come to first instance Trial on the issue of exposures below TLV’s as the next case may well set the tone for who benefits most from the lack of clarity offered by Bussey.

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ABC Asbestos Tools allows you to assess the likely asbestos fibre type to which the Claimant would be exposed, calculate the Claimants likely exposure and measure it against the TLV in place at the time. It also has a library of industry and medical publications and allows the user to assess what an expert would likely say, without the cost of obtaining that evidence. It allows the user to properly adopt a ‘nuanced approach’ to the assessment of the risk and its foreseeability, applied directly to the facts of the case.

Liability arguments are not dead, but are ever more fact specific and require more detail than ever before to allow insurers to put themselves in the shoes of the historical employer at the time of exposure and assess what approach to risk would have been taken by that employer at the time.