Does exposure to asbestos early in life increase the chance of developing mesothelioma? The success of a mesothelioma claim can often depend on showing the court that, ‘on the balance of probabilities’, it was likely that mesothelioma – the incurable cancer of the lung linings – was due to a level exposure to asbestos during the period of time when the claimant was employed at the company.

While settlements can and often are reached between several former employers who agree to award a proportion of damages to a claimant, the results of recent research also reinforce the claim that all asbestos exposure at any time in a victim’s life can cause mesothelioma.

Employer may try to deny the level of contributory exposure

The period of exposure may have occurred in the early part of a claimant’s working life, for example, when serving an apprenticeship at one particular workplace. But there may also be strong evidence to suggest that further exposures took place at different companies throughout a victim’s entire employment history. In a bid to reduce liability and the amount of mesothelioma compensation they might have to pay, a former employer will try to deny their level of contributory exposure to a victim’s mesothelioma, compared to any exposure levels at any other workplaces during the victim’s lifetime.

A defendant employer will not only vigorously contest their liability, based on identifying the specific cause of an asbestos-related disease amongst several workplaces in a former employees work history but also raise the issue of the time that has lapsed between original exposure and the appearance of asbestosis symptoms. In court, an employer defendant may simply argue that any exposure after the first few years would be unlikely to eventually lead to developing mesothelioma.

Difficulty in establishing one or more former employers’ liability

Claimants have always faced a significant difficulty in establishing one or more former employers’ liability for preventing or minimising the potential health risk of exposure, which eventually leads to the terminal cancer. An exceptionally long period of time of between 15 to 50 years or more may pass before the first symptoms of breathlessness, tight chests or coughing start.

Previous research has often suggested that individuals are likely to be more prone to developing mesothelioma or other asbestosis diseases if they were exposed early on in their life. Medical data seemed to show that the highest incidence of malignant pleural mesothelioma was among victims under the age of 20 when they were first exposed to asbestos. There is also the possibility of greater susceptibility to other types of cancers as well as an increase in deaths caused by strokes and heart disease.

More recent studies may help future mesothelioma claimants to challenge the idea that recent exposures to asbestos are unlikely to contribute to causing mesothelioma.

Risk of mesothelioma related to “cumulative” exposure to asbestos

A report published by The Collegium Ramazzini, an international academy of 180 scientists from 35 countries and experts in environmental and occupational health, clearly state that the risk of malignant mesothelioma is related to “cumulative” exposure to asbestos, i.e. all exposures, early as well as late, contribute to a total risk of developing mesothelioma.

The Academy is not alone in their conclusions. A number of published scientific studies now support the idea that mesothelioma is the result of cumulative asbestos exposure, rather than either early or recent exposure.

One recent study, which included 862 mesothelioma cases from more than 22,000 individual exposures across Europe, and as far afield as Australia, suggest that the risk of developing mesothelioma after an initial exposure never reduces, regardless of life expectancy. In other words, the risk of developing the fatal, incurable disease is still at the same high level or may even increase.

Emphasis on asbestos fibre counts

The research revealed that nearly 45 per cent of pleural (lung lining) mesothelioma cases, and more than 50 per cent of peritoneal (stomach) mesothelioma cases, were diagnosed at least 40 years after a first exposure. Even after 50 years, there were still over 13 per cent of pleural cases and 23 per cent of peritoneal cases recorded. It was also found that the rate and risk of pleural mesothelioma actually intensified for 45 years following a first exposure, which then appeared to advance but at a slower pace.

The Collegium has also cast doubt on the various criteria used in determining a diagnosis of diseases caused by asbestos, including the “over-reliance on detecting asbestos bodies” and fibre counts in lung tissue as an indicator of past exposure. There is also a concern over the lack of recognition that white ‘chrysotile’ asbestos fibres are now mostly found in pleural mesothelioma tissue.

Original risk levels were based upon observations of the most toxic blue ‘crocidolite’ and brown ‘amosite’ asbestos types used to manufacture insulation or fireproofing materials. As a result, they were banned in the mid 1980s, while white asbestos was considered ‘low risk’ and allowed to continue being used for a further 15 years.

Higher fibre number expelled over a shorter period of time

The reason for considering white asbestos as ‘low risk’ was because the curly structure of white chrysotile fibres. The less rigid fibres were more able to be “broken down” by the immune system and lead to a higher fibre number expelled from the lung linings over a shorter period of time. Today, chrysotile has been confirmed as a Class 1 cancer-causing substance without a confirmed threshold level, below which, exposure would be considered safe for human health.

The ongoing research may also suggest why a steady number of mesothelioma patients continue to be diagnosed since asbestos was first banned just over thirty years ago. More than 2,500 people now lose their lives to mesothelioma every year – up by more than 10 per cent since 2011 – according to the latest available figures from Health & Safety Executive (HSE) Annual Report, 2014.

However the research also means that mesothelioma victims and their families should increasingly expect to see a more favourable outcome when claiming damages from former employers, no matter when exposure to asbestos occurred.