High Court consideration of material contribution to risk and the principle of de minimis in a mesothelioma claim

19 May 2020

Valerie Bannister v Freemans Plc [2020] EWHC 1256 (QB)

(HH Geoffrey Tattersall QC sitting as a Deputy Judge of the High Court)

BLM acted for the defendant in this claim.

We examine a claim involving a mesothelioma victim who had allegedly been exposed to a very low transient dose of asbestos on a single occasion in his life. The court found that:

  1. the claimant had failed to prove that the dust to which the deceased had been exposed had contained asbestos fibres; but in any event
  2. if the dust had contained amosite fibres as alleged, the level of asbestos fibres within the dust would not have materially increased the risk of mesothelioma to anyone exposed to it.     

The facts

The claimant’s husband unfortunately developed mesothelioma, of which sadly he died in 2019, having given evidence on commission. He had been employed by the defendant as a manager in its accounts department for about 10 years. He had worked in an office environment throughout his adult life and, when informed of a diagnosis of mesothelioma, on more than one occasion told his medical advisors that he had no recollection of ever having been exposed to asbestos fibres. He was subsequently reminded by former colleague X about an incident in the 1980s, where they had been notified by a memo that asbestos material was to be removed from their office partitioning over the course of the following weekend. They had allegedly returned on the Monday to find visible dust left in the office that they believed must have contained asbestos fibres. The dust did not trouble the deceased, who worked normally and did not say that he had had to clear it from his desk. The dust was removed by office cleaners at the end of the day.

Evidence at trial was given by X, who recalled receiving a memo notifying them that work involving asbestos removal was to take place over the following weekend. He recalled visiting the deceased on the Monday and noticing the presence of dust.  

The defendant was unable to adduce any documentary or witness evidence but submitted that, on the claimant’s case, it had: (1) identified works potentially involving disturbance of asbestos (2) arranged for the partitions to be removed by contractors when its employees were absent; and (3) alerted its employees to the nature of the work. This showed a responsible approach to asbestos risks and was not consistent with permitting a residue of asbestos dust after completion of work.  

It was admitted that, if the dust had contained asbestos fibres, the defendant was in breach of statutory duty, but it was disputed that the level of fibres involved would have materially increased the risk of mesothelioma.

Expert liability evidence

For the claimant, John Raper estimated an exposure dose of 0.001 f/ml years, assuming the dust contained asbestos, whereas Martin Stear for the defendant estimated a dose of 0.00021 to 0.00058 f/ml years. The experts agreed that these figures were illustrative and not definitive and that, if asbestos had been present, it would probably have been amosite. 

Following cross-examination at trial, Mr Raper conceded that there was some inconsistency in his figures which, when removed, left him with an estimate of 0.0004 f/ml years which was consistent with Mr Stear’s evidence.

Expert medical evidence

For the defendant, Dr John Moore-Gillon’s evidence was that:

  • According to Peto, someone of the deceased’s age with no known history of asbestos exposure had a lifetime risk of developing mesothelioma of 0.08% (agreed by Dr Robin Rudd for the claimant)
  • Extrapolating from the Hodgson & Darnton paper (“H&D”), if the assumed dose had been 0.0005 f/ml years, there would be a risk of 0.2 deaths per 100,000 exposed, which would be regarded by H&D and the Health & Safety Executive as insignificant
  • Given the deceased’s age at the time, the estimated annual risk of him developing mesothelioma from such exposure had been 1 in 50m
  • If the dose was 0.0004 f/ml years, the risk was lower still
  • There was no significant medical risk from this exposure

Dr Rudd’s evidence was that the deceased`s exposure gave rise to a “small but more than negligible risk”, that he may have told a patient that it constituted “a very small chance” of causing mesothelioma and not to worry about such a risk. But people did worry about such risks. He accepted that there were certain levels of exposure which were so trivial that he would dismiss them, but was unable to say what risk level he would conclude not material.

The Judge’s findings

The Judge was satisfied that the defendant had probably used specialist contractors, because why advise employees about the asbestos only then to ignore the risks associated with it by engaging non-reputable contractors? Specialist contractors would not have left asbestos dust and it was more likely that contractors subsequently replacing the partitions left the dust. On the balance of probabilities, the deceased had not been exposed to asbestos dust from the work.

Having found against the claimant on the facts, the Judge nevertheless went on to deal with the causation issue. He concluded that:

  • H&D is the best research available. Although any conclusions drawn from it were not definitive, it offered a reliable but rough and ready indication of the degree of risk
  • Dr Moore-Gillon had attempted to evaluate the significance of the dose by reference to the statistical risks provided by epidemiology, and concluded the risk was insignificant and “vanishingly low.”
  • Dr Rudd conceded that there were some cases where exposure was so trivial that it was immaterial, but could not explain on what basis the Judge could assess whether there was a material increase in risk. He did not assess what level of risk, if any, was created by the deceased’s alleged exposure or whether such risk was more than de minimis
  • In Sienkiewicz, the Supreme Court established that what constitutes a material risk must be for a Judge on the facts of the particular case
  • The test for material risk propounded by Dr Rudd in the case of Sloper, and agreed by Dr Moore-Gillon, is appropriate ie. “…a dose of asbestos which was properly capable of being neglected could be defined as a dose which a medical practitioner who is aware of the medical risks would define as something that the average patient should not worry about.”
  • The claimant had not established, on a balance of probabilities, that the alleged exposure gave rise to a material increase in the risk of the deceased suffering from mesothelioma.

What this means for you

This is a first instance decision, which the defendant won on the facts. Nevertheless, the Judge went on to make findings on the principle of de minimis in mesothelioma claims, in essence finding that the defence of de minimis may exist even where the alleged exposure is the only exposure known. However, the level of exposure, and thus the risk arising, was extremely low in this claim.

A statistical analysis of risk based on the Hodgson & Darnton paper was found to be indicative and not determinative, but it is important that the experts understand the epidemiology. Ultimately, what constitutes a material as opposed to insignificant increase in risk is a matter of fact and law for the Judge to determine. 

The court did not give any indication or approximation of what level of dose may be considered significant, or below which one could be confident of establishing a de minimis defence, and it is unlikely any court will do so. Each case will be a matter for the Judge. Where there is evidence of exposure elsewhere, there will always be a better prospect of establishing a de minimis defence.      

David Platt QC represented the defendant; Harry Steinberg QC and Gemma Scott were for the claimant, instructed by Field Fisher.

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Disclaimer: This document does not present a complete or comprehensive statement of the law, nor does it constitute legal advice. It is intended only to highlight issues that may be of interest to clients of BLM. Specialist legal advice should always be sought in any particular case.

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