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Significant low-exposure asbestos decision considers Fairchild ‘material increase in risk’ principle

  • 21 May 2020 21 May 2020

The High Court has handed down a judgment on a low exposure asbestos claim, accepting for the first time epidemiological and medical evidence on what is considered a material increase of risk under the principles set out in Fairchild.


Bannister (Estate of) v Freemans Public Limited Company (Rev 1) [2020] EWHC 1256 (QB)

The Defendant had advanced a de minimis defence. Litigators have struggled with the utility of such defences for many years given the circular definitions used in the appellate courts over the years. Terms such as ‘more than minimal’, ‘significant’ or ‘material’ have all been used to describe the benchmark whether in terms of damage caused or, in the disease setting, exposures causing an increase in risk.

The reluctance of the courts to lay down more useful benchmarks has derived from a belief that the question should be treated as a fact specific one ('you know it when you see it’). In this instance, however, the experts and the Court appear to have agreed that a de minimis risk was one that a doctor, considering the risk on a prospective basis, felt able to advise a patient that the risk was such that there was no justification for worrying about it.

This is a useful formulation, although obviously informed, as here, by a full analysis of the risk in a particular case; one which permits litigators to question their experts in advance and cross-examine the opponent's experts at trial.

The judge reminded the parties that the burden of proof remained with the Claimant, a reality that is often ignored by claimants in mesothelioma cases.

Ultimately, the High Court found the Claimant had not proved the Deceased had been exposed to asbestos, and further held that had the Claimant proved the exposure, it would have been treated as de minimis and the claim would have failed in any event.


The Deceased died of epithelioid malignant mesothelioma in March 2019. He alleged he had been exposed to asbestos in 1983-84, when employed by the Defendant, after the removal of a partition wall containing asbestos. He stated that on the Monday morning there was visible dust all over his desk and on the floor. The alleged exposure continued throughout the week, as the dust was gradually removed in the evenings by cleaning.


Geoffrey Tattersall QC, sitting as a High Court judge, considered three issues:

  1. To what degree, if at all, was the Deceased exposed to asbestos during the relevant period?
  2. What was the extent of the exposure to asbestos dust?
  3. Whether any such exposure constituted a ‘material increase in risk’ of the Deceased developing mesotheolioma?

Was the Deceased exposed to asbestos?

Mr Tattersall QC found that the panels in the Deceased's office were made of asbestos and had been removed by the Defendant. The Court found the Defendant had warned its employees of the asbestos removal by way of a memo. The Defendant “probably used reputable and specialist contractors to undertake the works”, as sending the warning and then using non-reputable contractors would have been counter-intuitive. These specialists would not have allowed employees to be exposed to asbestos dust.

Therefore, on the balance of probabilities, the Deceased failed to prove that the dust he referred to was asbestos dust.

This was sufficient to confirm that the claim would fail.

What was the extent of the exposure to asbestos, and did this constitute a ‘material increase in risk’?

The Judge, however, went onto assume that the Deceased had been exposed to asbestos dust during the week in question, those levels gradually reducing from Monday to Friday.

In considering this, the Judge held that epidemiology has a part to play in ascertaining whether there was a material increase in risk under the Fairchild test. He was satisfied that when determining whether there is a material increase in risk "it is appropriate to have a very limited engagement with statistical risks provided by epidemiology and with the views of medical experts."

On the extent of the exposure, the parties’ experts gave evidence as to the cumulative dose the Deceased was ‘exposed’ to. The Judge stated he was "entitled to have regard to any such estimates as rough and ready indications" of the exposure. The judge preferred the evidence of the Defendant’s expert, Mr Martin Stear, and found that the total cumulative dose the Deceased was exposed to was 0.0004 fibre/ml years.

The Judge then moved on to consider how the dose estimate should be used in assessing risk and preferred the Defendant's evidence overall. The Defendant's expert, Dr John Moore-Gillon, submitted that by using a dose estimate of 0.0005 fibre/ml years and analysing the 2000 study from Hodgson and Darnton paper, there would be a risk of 0.2 deaths per 100,000 exposed.

Based upon the Hodgson and Darnton study and guidance from the HSE, this figure would be regarded as insignificant. Therefore, if the dose estimate was of 0.0004 fibre/ml years the risk was even lower.

Dr Moore-Gillon further stated that given the Deceased's age at the time of the exposure the estimated annual risk of him developing mesothelioma from such exposure had been 1 in 50 million. He opined that there was no significant medical risk associated with this exposure.

The Claimant's expert stated the Deceased's exposure was a "small but more than negligible risk" and that people worried about such risks. However, on cross-examination he accepted there were certain levels of exposure which were so trivial that he would dismiss them, but the judge noted he did not make any "attempt to assess what level of risk, if any, was created by any exposure to asbestos whilst the Deceased was in the employment of the Defendant or whether such risk was more than de minimis."

The judge further stated that the Claimant's expert was "straining logic and common sense to regard an annual risk of 1 in 50 million as a material increase in risk".

The Judge accepted that this risk would not be regarded as medically material and that exposure at this level could not be considered a ‘material increase in risk’ and was therefore de minimis. He concluded that if the dust in the Claimant's office had included asbestos fibres, the level within the dust would not have materially increased the risk of mesothelioma to anyone exposed to it.

What can we learn

  • The decision has provided much needed clarity and confirms that when addressing the concept of a ‘material increase’ in risk, the Courts can consider both medical and epidemiological assessments of that risk.
  • On the risks associated with low-level asbestos exposure, the Judge concluded that Hodgson & Darnton is the "best and most appropriate paper available" and it can "offer a reliable but rough and ready indication of the degree of risk to which the deceased was exposed."
  • The decision also reiterated some guidance on why the evidence of lay witnesses in historical disease claims should be viewed with particular care, specifically Mr Justice Leggatt’s comments in Gestmin SPGS SA v Credit Suisse (UK) Limited that difficulties arise due to "the unreliability of human memory". He continued that "the nature of litigation is such that witnesses often have a stake in a particular version of events" and "it is important to avoid the fallacy of supposing that, because a witness has confidence in his or her recollection and is honest, evidence based on that recollection provides any reliable guide to the truth."
  • It is likely that claimants will not like this decision and will be looking for an opportunity to appeal. Indeed the Claimant in this case has indicated his intention to apply for leave to appeal.


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