There are increasing numbers of claims being intimated from Claimants suffering from mesothelioma who allege low level bystander exposure. However, caution needs to be exercised before automatically attributing causation for the condition to specific alleged exposure, rather than taking a close look at environmental, background exposure.

It is particularly difficult to rebut allegations of negligent exposure involving low dose cases which involve occupations not typically associated with exposure to asbestos.

One such example could be those cases where claimants are increasingly seeking to attach liability for low level asbestos exposure to individual schools and local authorities, despite the likelihood of asbestos being present in a wide variety of locations. Where there are allegations of exposure to asbestos occurring many years previously whilst attending or working at schools, there is often little information with regard to potential exposure there and elsewhere. Differentiating between these competing potential causes can be impossible, or at least extremely difficult.

Perhaps the most emotive instance is that of 28 year old Leigh Carlisle who tragically died last summer and whom it is believed developed mesothelioma either from her primary school or by taking a short cut through a factory yard where asbestos was cut.

It would be helpful if the Health & Safety Executive provided greater clarity on background asbestos levels in the UK's public buildings if Defendants are to have any chance against spiralling low level exposure claims. There is certainly a need to look closely at the general issue of background asbestos levels so that greater certainty can be reached on an individual Claimant's likelihood of exposure.

In 2006, the Health & Safety Executive Watch Committee published an assessment of the potential exposure of teachers and others from the use of drawing pins on asbestos insulating board in a school classroom setting, but the scientific methodology employed was called into question.

In theory, given the appropriate facts and evidence, it should be possible to argue that, even though the Defendant may have exposed a Claimant/Deceased to asbestos and even if that exposure was negligent, it did not materially increase the risk of the mesothelioma developing (the causation test in Fairchild) because it did not materially exceed the background level of asbestos in the community as a whole. However, recent case law would suggest that such a defence is difficult to succeed in the current climate, particularly where post 1965 exposure is involved.

In Pinder v Cape Plc [2006], the Claimant, John Pinder, developed mesothelioma as a result of playing in an asbestos waste tip as a child in the 1950's. The High Court rejected Pinder's claim that:

  1. The Defendants could not have foreseen he, or other children would play within its grounds, which was, at the time, controlled by the local Council.
  2. The Defendants were under no duty to provide advice to the local Council regarding the safe disposal of asbestos it had delivered to the tip.

The key factor in this case was that exposure was prior to 1965 when the risks from such exposure were not appreciated and it was outside the workplace.

In Jones v Metalbox Limited and Crown Cork & Seal Limited [2007], the court examined the likelihood of mesothelioma being caused by limited exposure to chrysotile (white asbestos). The deceased's exposure was described as:

"Small amounts of dust invisible to the naked eye" arising from the asbestos conveyor belts on a production line".

The Judge found that there was not a threshold exposure to chrysotile below which there was not an increased risk and that the Asbestos Regulations [1969] standards were merely guidelines as to the levels of dust that would avoid a prosecution. They did not lay down safe levels of exposure. The Judge further stated that the general view of national and international bodies is that there is no threshold below which exposure to chrysotile can be regarded as safe and that if a person is exposed to chrysotile at levels above those found in the environment at large, then he is satisfied that that person has an increased risk in respect of mesothelioma. On this basis, it was held that the exposure was "more than trivial" and therefore increased the Claimant's risk of contracting mesothelioma.

In Brett v University of Reading [2007], although the Deceased was likely to have been exposed with a number of employers, the Claimant only elected to sue the Defendant. It was alleged that the deceased was exposed to low levels of asbestos dust whilst supervising work, which included the removal of asbestos from an old library at the university in the 1980's.

Whilst there was evidence that the deceased came into contact with asbestos, there was no evidence the Defendant had not taken the necessary precautions or otherwise failed to discharge its duties. The Court of Appeal made it clear that the development of mesothelioma does not inevitably lead to a conclusion that there must have been a breach of duty which the Claimant must in turn prove. However, the facts are very specific in this case. Certainly Sedley LJ, also made it clear that had the Claimant/Deceased only been exposed during his employment with Reading University;

"the inference that this is where it did occur will be practicably irresistible"

and further commented;

"any unlawful exposure of the employee to airborne asbestos will ordinarily constitute such a contribution if mesothelioma developed".

As such, despite the lack of evidence, had the deceased only alleged exposure with one Defendant, the suggestion is the Court would have inferred the Claimant had been unlawfully exposed by the Defendant.

Another example of a case involving very low levels of exposure is the 2009 decision in Diane Willmore v Knowsley Metropolitan Borough Council which held that the local authority was liable in negligence to the Claimant, the Judge having found that her exposure to asbestos dust was likely to have had occurred from ceiling tiles in a secondary school where she was a pupil in the 1970's.

Despite there being no specific measurement of the duration of exposure, it was held that the exposure (although the Judgment frequently referred to the "risk" of exposure rather than "actual" exposure) had been more than de minimis and had materially increased the chance that she would develop mesothelioma later in life.

The Judge commented :

"The fact that mesothelioma can be triggered by very small quantities of asbestos dust does have the consequence that it may in principle have been caused by asbestos encountered in the general environment or from some other unknown cause. Mr Feeny, on behalf of the Defendant, referred to research by Julian Peto and Others 'Occupational, Domestic & Environmental Mesothelioma Risks in Britain', a case controlled study, published in March 2009, to show that in a high proportion of cases, it had not been possible to identify a particular source of asbestos exposure. Thus, even if the Claimant's mesothelioma was probably caused by asbestos, this could have been encountered in the general environment or from some other unknown source".

In spite of this and taking the advice of Maurice Kay LJ in Rolls Royce Industrial Power (India) Limited v Cox [2007], he did not consider any specific measurements of the duration was necessary. On the issue of measurement, he referred to Dr Rudd's evidence:

"It will be a matter for the court to determine on the basis of the evidence presented by witnesses and consultant engineers from which source or sources Mrs Willmore sustained significant asbestos exposure where 'significant' is defined in accordance with the definition adopted in relation to mesothelioma causation by the Industrial Injuries Advisory Council in their 1996 report (Cm 3467|): 'a level above that commonly found in the air in buildings and the general outdoor environment'. It would be appropriate for the Court to conclude that each such exposure materially increased the risk that she would develop mesothelioma".

One might however ask how a Court can determine if the level was in excess of building and environmental levels if there is insufficient guidance on background levels and no specific measurement of alleged negligent exposure is deemed to be necessary in these cases.

In Willmore It was held that the Claimant was negligently and causatively exposed to a risk of asbestos fibres in the following circumstances which were not de minimis.

  1. From the work done to the ceiling in the T shaped corridor and the temporary stacking there of ceiling tiles (some of which were broken or chipped) over a few days;
  2. From damage to ceiling tiles by the misbehaviour of pupils removing them and pushing bags and items of clothing up into the ceiling void;
  3. From vandalism of the girls' toilets in the junior block and the storage of damaged tiles there for a period of about two weeks.

A case in contrast is that of Terence Charles Abraham v (1) G Ireson & Son (Properties) Limited (2) Stanley Reynolds (t/a Reynolds a& Spademan (A Firm) [2009]

In this case, the Claimant was a plumber's apprentice and then an apprentice with the First Defendant. He worked later for the Second Defendant, a plumbing firm and left in 1965, so there was a further period of exposure to 1965.

Exposure with the First Defendant was light and intermittent. It was more frequent with the Second Defendant but still modest and infrequent. Exposure was likely to have been causative and could have been avoided because alternative asbestos free materials were available at the material time.

It was held that neither the First nor the Second Defendants could before the publication of the Newhouse and Thompson paper in 1965, have been aware that the asbestos dust was likely to be injurious to the claimant. As they did not know and could not reasonably have been expected to have known of the risk of injury arising from the Claimant's exposure to the dust, having no special degree of knowledge, it could not have been reasonably practicable for them to take any steps to protect him from it.

Whilst this case involved low level exposure, there was not an issue as to whether the exposure was causative and therefore whether environmental exposure was more likely. The determinative facts in this case were the period of exposure, the level of exposure and given that level, the knowledge of the Defendants.

Non work place exposure was however of relevance to the issue of the Defendant's knowledge as the Judge considered that having regard to the fact that at the time asbestos products were still in use in domestic and other everyday settings, even if the Defendants had sought advice on the Claimant's limited use of asbestos at the time, the response would in all probability have been that there was no need for the Defendants to be concerned about any risk of injury from the use of those products. The First and Second Defendants were found not to be negligent.

Clearly if Defendants are going to have any success in defending low level asbestos exposure claims, more guidance as to environmental levels is required, so that alleged culpable exposure can be demonstrated to be minimal, although it would appear a court will be keen to find an alternative source if there is evidence of above de minimis exposure elsewhere after 1965.

This issue is of increasing importance, bearing in mind the recent Peto research in April last year, which revealed that the number of population deaths due to mesothelioma could be significantly different from the current HSE projections.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.