Developments in low exposure to asbestos litigation: Bannister, Johnstone, and Kerr

Following the recent decision in Kerr and others v Midlothian Council and another  [20.12.24] we consider the key findings and reflect on developments in low exposure to asbestos  litigation. In doing so we also consider potential future developments in light of Johnstone v Fawcett’s Garage which is due to be heard in the Court of Appeal in February.

Kerr and others v Midlothian Council and another  [20.12.24]

The claim was brought against two local authorities in Scotland. It was alleged that the deceased had contracted a peritoneal mesothelioma from working with Bunsen burner mats comprised of asbestos cement. Exposure was found to be to chrysotile and amounted to 0.001 fibre/ml years or less.

The pursuer argued that the Fairchild rule of causation applied and therefore the threshold to be met was to establish that there was a material contribution to risk.

Epidemiology evidence obtained by the defenders showed no relationship between low chrysotile exposures and peritoneal mesothelioma.  

With the court’s acceptance of the second defender’s expert evidence the court looked to the approach as argued in Bannister and now for further adjudication in the Court of Appeal in Johnstone.

Aside from the method of approach for assessing materiality, Kerr is important for two additional reasons:

1. The court accepted there was no association between chrysotile exposure and peritoneal mesothelioma.
2. The court found that the Fairchild rule did not apply to the claim. Fairchild imposes a relaxed test of causation removing the need for proof of factual causation and replacing it with proof of increased risk. Here, the pursuer could not prove that the mesothelioma was caused by asbestos.

Reflecting on key litigation: Sloper, Bannister, Ness, and Johnstone

In recent cases south of the border various methods have been suggested for assessing materiality. These can be  summarised as follows:

Sloper v Lloyds Bank [2016]

This case involved alleged exposure to asbestos in relation to renovation to ceilings in a bank. The Defendant deployed medical and occupational health evidence to argue that the exposure would not be material. Whilst this method was asserted at trial, it was not ruled on following a finding of no exposure.

Bannister v Freemans [2020]

This case concerned a single morning of exposure to amosite on a desk after renovation to office space. The alleged exposure was 0.00068 f/ml yrs – 0.00027 f/ml yrs if it occurred but the Court found there was no exposure . However it did apply epidemiology and the causation issues were fully argued. 

Ness v Carillion Contracts [2023]

The alleged exposure in this case related to cutting Asbestos Insulating Board. The alleged exposure was 0.0042 f/ml yrs – 0.0058 f/ml yrs. The claim was unsuccessful. No expert evidence was heard on the issue of or risk of medical significance. The court applied a relative assessment of exposure by reference to other defendants / occupational exposures.

Johnstone v Fawcett’s Garage [2023]

The claim in this case relates to bystander exposure from working in an adjacent office within a car garage where asbestos friction materials were used. The alleged exposures - Occupational: 0.001 f/ml yrs – 0.002 f/ml yrs; and Environmental: 0.0026 f/ml yrs – 0.046 f/ml yrs. The court made the findings on materiality.  This case is subject to appeal being heard by the Court of Appeal in February.

The claimant  contends that risk materially increased on either assessment of exposure or environmental levels.

The defendant has introduced a further methodology for assessing materiality akin to that in Bannister which is an absolute risk model. It does not look at risks relative to the background exposure risk but adopts the Hodgson & Darnton assessments and then applies medical evidence to consider if that risk would be considered medically significant.

It remains to be seen if the Court of Appeal will  allow an analysis that utilises Hodgson & Darnton coupled with expert assessment of medical significance. The hearing is listed for 13 February 2025 and judgment is expected later in the summer.

Peritoneal mesothelioma: a special category case?

The key difference in Kerr over the previous low dose judgments is the involvement of a peritoneal mesothelioma and not pleural disease.

It has always been thought that higher exposures are required compared with pleural disease mainly because the route to the peritoneal lining is more indirect. However, until Kerr the differences in risk had never been forensically tested.  

The deployment of epidemiology evidence in Kerr resulted in the court finding that there was no association between low dose chrysotile exposure and peritoneal mesothelioma. i.e. chrysotile did not cause mesothelioma.

The key takeaways are as follows:  

1. For those cases involving peritoneal mesothelioma and chrysotile exposures they are now, on this basis, defendable.
2. It will be essential to carefully consider exposure and the type of exposure in all peritoneal exposures to see if exposure falls into the low dose / chrysotile exception.
3. Whilst the focus of Kerr was on chrysotile exposures, even where very low doses to amphibole exposure exists akin to Bannister careful consideration ought to be given to the risks generated and if the claimant can show a significant increased risk.

Practical assessment  

The starting point for insurers is to consider exposure, fibre type and dose at least initially before incurring the cost of expert evidence.

Once an early informed view of exposure, dose and fibre type is taken then consideration can be given to a likely annual and lifetime risk in conjunction with a Hodgson & Darnton assessment.

Aided by handling expertise and technology these initial assessments can be taken to identify cases of low exposure as early as possible  and help ensure the appropriate expert evidence is obtained.

What does the future hold?

We are likely to see increasing numbers of lower dose claims involving claimants in non-industrial roles. The courts have tended to accept arguments based on epidemiological assessment via Hodgson & Darnton coupled with medical opinion.

Attention will now turn to the outcome of the appeal being heard by the Court of Appeal in Johnstone and whether the approach accepted in Bannister and Kerr will be approved.

If approved, it will seemingly do what Lord Phillips thought was impossible in Sienkiewicz v Greif [2011] by giving guidance on what is material and will give a clear route of challenge to low dose cases.