Author: Rachit Buch, 12KBW

Steven Snowden KC, John-Paul Swoboda KC and Helen Waller of 12KBW acted for the appellants in Alexander Johnstone (Personal Representative of the Estate of Elaine Johnstone, Deceased) and Fawcett’s Garage (Newbury) Limited.

The Court of Appeal has handed down judgment in this case addressing the material increase in risk of contracting mesothelioma.

Elaine Johnstone was exposed to asbestos while working at Fawcett’s Garage over a period of around 7.5 years. She contracted malignant mesothelioma in 2018 and, sadly, passed away in 2019.

At first instance, H.H.J. Simon, sitting as a High Court Judge, found that her exposure to asbestos was at such low levels of chrysotile that the risk of Mrs Johnstone contracting mesothelioma had not been materially increased by the admitted breaches of duty.

The appeal, brought by Mr Johnstone, was dismissed.

First instance decision

H.H.J. Simon found that:

  1. The Garage’s mechanic (who provided the only factual evidence relevant to exposure, read at trial) was exposed to around 1.0 fibres per ml of air per year (fb/ml-y) of chrysotile asbestos.
  2. Mrs Johnstone’s exposure was around 0.001 – 0.002 f/ml-y as she worked primarily in an office, across the yard from the mechanic’s bay.
  3. Given background levels of asbestos, this exposure increased the risk of contracting mesothelioma by “0.1% or less”, which was not a material increase.

Appeal

There were five grounds of appeal; four of which concerned the way in which H.H.J. Simon calculated the increase in risk of mesothelioma; one argued that adverse inferences from the failure to obtain and keep air monitoring records should have led to the claimant’s expert evidence on dose being accepted.

The Garage also submitted a Respondent’s Notice which sought to support the Judge’s decision by reference to the approach in Bannister v Freemans Plc [2020] EWHC 1256 (QB).

In a joint judgment, Coulson, Nicola Davies and Zacaroli LJJ’s held:

  1. There was no error in H.H.J. Simon’s rejection of the adverse inference argument. There was insufficient evidence that the obligation applied; in any event, adverse inferences cannot require a judge to ignore factual findings properly made. In this case, the Court was not balancing opposing witnesses (one side having been hampered by another’s failure to provide relevant evidence or documents) but was analysing uncontested factual evidence with the help of expert evidence.
  2. The judge was entitled to use the ‘direct risk assessment’ approach on the evidence heard, extrapolating the risk of mesothelioma from occupational vs background risk, from the Hodgson & Darnton study. The evidence of the epidemiologist called on behalf of the claimant (Prof. Norrie), in context, was not as dismissive as suggested on appeal.
  3. The Judge’s calculation of the background risk contained an error but this did not affect the overall conclusion that increase was ‘less than 0.1%’. The court should not take the most favourable part of the ranges of occupational and background risk to arrive at the figure for increase.
  4. There was no error of law in accepting the direct risk assessment approach. The caution about use of statistics in Sienkiewicz v Grief (UK) Ltd [2011] UKSC 10 applied to cases decided on ordinary ‘but for’ principles of causation; and the defendant was not required to bear all consequences of evidential difficulties and uncertainties. The Judge’s decisions on relative risk were open to him.
  5. The judge did decide to accept the defendant’s approach to risk; there was no failure to make a decision or provide reasons.

Comment

At the heart of the appeal was the judge’s assessment of the increase in risk of mesothelioma caused by the low dose of exposure.

The claimant had argued that occupational exposure should be compared to background or environmental exposure and if it was a more than minimal increase, a material increase in the risk would be established. This was referred to as the ‘exposure/risk approach’ on appeal.

The defendant had argued that the Hodgson & Darnton model could be used, with evidence from Peto and Rake on the background risk of mesothelioma, to assess the risk of contracting mesothelioma at various levels of exposure.

It also sought to support the assessment of risk approved in Bannister – that a material increase in risk is one which an appropriately qualified doctor would regard as medically significant (referred to as the ‘absolute risk approach’).

The significant consequences of the appeal decision are:

  1. Direct risk assessment, and reliance on Hodgson & Darnton, is a permissible method of evaluating material increase in risk of mesothelioma in low exposure cases. The Court of Appeal found there was no error in principle or in assessing the evidence produced in the Judge’s decision.
  2. The Court of Appeal was explicit in stating that the appeal “is not about deciding whether the direct risk assessment approach is, generally, a valid and appropriate method.” The appeal was concerned with the Judge’s decision and its validity.
  3. In litigating cases involving low dose exposure, it will still be open to claimants to argue that material increase in risk is established using an analysis of exposure and risk or to challenge the use of Hodgson & Darnton. They will have to assess the risks of doing so in light of support for direct risk assessment provided in Johnstone.
  4. The Court of Appeal did, however, rule out use of the absolute risk approach. This delegates assessment of materiality to a medical expert (as argued by Mike Rawlinson KC of 12KBW here shortly after Bannister was decided). The example given in the judgment is an increase from a 0.1 in 100,000 chance of contracting mesothelioma to 0.9 in 100,000 by tortious exposure. This would be a nine-fold increase but still considered a medically insignificant chance overall. Unequivocally, the conclusion was that “we do not accept the absolute risk approach is appropriate in cases where the court is required to assess the material increase in risk of a claimant contracting mesothelioma.”
  5. Unlike the decision on the appeal grounds (explicitly phrased as not determining the validity of the approach to causation), the decision on the Respondent’s Notice is in terms that apply to all mesothelioma claims and bind first instance Courts.