Widespread industrial and commercial use of asbestos fibres in the production of insulation and fireproofing products throughout most of the twentieth century meant that countless thousands of British workers were likely to have been exposed to the material at more than one place of work during the course of their lives.

Decades later, the challenge for the many workers who eventually succumbed to asbestosis disease or developed the fatal, incurable mesothelioma cancer is not only for their asbestosis lawyer to trace original employers or their insurers but also to prove liability of an individual employer and the degree of responsibility towards the employee’s disease.

The law requires that a person suffering injury must show “on the balance of probabilities” that the defendant’s “negligence” caused the injury or condition, without which, the claimant would not have suffered the damage. However, if exposure is only partly due and not totally the result of a defendant’s negligence the defendant will be liable to the extent that their breach of duty has materially contributed to the disease.

Asbestosis – a ‘divisible’ disease

With some asbestos-related diseases, such as pleural thickening and asbestosis, the greater the exposure the more likely the disease will develop and its severity increases. Known as “divisible” diseases, there are a number of identified times when exposure to asbestos occurred, and the increased probability that they all would be a “contributory” cause. Consequently, emergence of the disease can be divided between the different times when exposure occurred.

During an asbestosis claim case, for every defendant who has exposed a claimant to asbestos it will be necessary to determine the extent to which the claimant was exposed at each defendant’s workplace. The emphasis will be on ‘cumulative’ exposure, which has been the cause and/or contributed to each of the diseases. As a result, a percentage only of the claim will be recovered when not all of the defendants, including Insurers, can be found liable.

Mesothelioma – an ‘indivisible’ disease

In a mesothelioma claim case, the approach is different because the disease is recognised as being “indivisible”, and there is no known threshold of asbestos exposure below which mesothelioma cannot occur.

Medical practitioners cannot prove whether exposure at a particular defendant’s workplace had caused mesothelioma beyond stating that exposure will have materially increased the risk and any more than minimal exposure will have materially increased the risk so that that defendant can be held responsible.

There only needs to be “one event where there is exposure to asbestos for mesothelioma potentially to develop”. Consequently, just because the claimant cannot establish which defendant had caused the mesothelioma, the argument that none of the defendants could therefore, be held responsible, can be dismissed if can be established against one particular defendant that exposure was more than minimal.

One exposure event is sufficient

Hence, the emergence of mesothelioma, which cannot be divided between the different times when exposure occurred, will have a corresponding impact on apportioning claims between different employers / insurers. In a mesothelioma compensation case, it would be sufficient for the claimant to show that a negligent exposure had materially increased the risk of developing the disease.

As part of Compensation Act 2006, the “Mesothelioma damages” amendment, Section 3(1) states that where : (1) a person has negligently or in breach of statutory duty exposed the victim to asbestos and (2) the victim has contracted mesothelioma as a result of exposure to asbestos, but (3) it is not possible to determine with certainty whether it was this or another exposure which caused the disease and (4) the person in question is liable… “whether by reason of having materially increased a risk or for any other reason.”