Low level exposure to asbestos can cause the development of diffuse pleural thickening (DPT) – an asbestosis condition which often leads to the non-malignant scarring of the outer lining of the lung. A victim who can clearly show that asbestos exposure was responsible for a confirmed diagnosis of pleural thickening is entitled to claim asbestos compensation for the “proportion of respiratory disability caused”.

A former employer may argue that the level / amount of exposure was not enough to have caused the condition. However a court will refer to expert medical testimony and guidance on tested minimum exposure levels for pleural thickening as well as for mesothelioma cancer, which have previously relied on fibre counts over a set period of time. The claimant’s working conditions are also considered and whether adequate safety measures were in place at the time, as legally required of an employer.

There were 370 new cases of pleural thickening assessed for Industrial Injuries Disablement Benefit in 2016 (Health and Safety Executive, November 2017) – a rise of 9 per cent on the annual average of 340, and nearly 2.5 times the 150 cases diagnosed in 1991.

Many more could be at risk of suffering the debilitating symptoms

Because pleural thickening can develop after a relatively low level exposure to asbestos, many more could be at risk of suffering the debilitating symptoms. Pleural thickening and calcification of the lung lining reduces its elasticity and ability to fully function. A victim will start to experience symptoms such as shortness of breath, feeling of tightness across the chest and general chest pains.

More worryingly still, despite being considered a relatively benign condition, over a period of time more serious symptoms may develop resulting in asbestos-related lung cancer. In an estimated one in four of pleural thickening cases, the level of disability caused by a worsening of the condition will increase on and off in the first ten years after an initial confirmed diagnosis.

In recent years, the courts have increasingly considered the contribution of even a very low level of exposure may have upon a victim suffering with breathing problems caused by pleural thickening. It was not always the case – a claim for pleural thickening once posed a difficulty in being accepted. Victims were only considered to be at an increased risk of developing an asbestos-related disease as a “direct result of their exposure to asbestos” rather than because of the “existence of asbestosis symptoms, themselves”.

It means that an employer’s defence over the fibre levels accumulated may no longer be sufficient to completely determine the outcome of a pleural thickening claim. Defendants would refer to previous guidelines set out by the “Helsinki Criteria” of 1997.

Low levels of exposure could be disputed

The Criteria set the fibre ml level at 25 fibre/ml per year or above, at which mesothelioma, asbestosis or lung cancer may be held to have been caused by asbestos exposure. The level would be determined on a scale from 1 year’s ‘substantial’ exposure at 25 fibre/ml through to 5 years ‘moderate’ exposure at 5 fibre/ml per year. This would mean that the often low levels of exposure that can lead to pleural thickening could be disputed.

However, in 2005, the Industrial Injuries Advisory Council (IIAC) re-examined the initial criteria, and also obtained evidence to show that the risk of an asbestos-related condition varied between different industries at similar levels of cumulative exposure. This meant that it was no longer always necessary for claimants to prove that they were exposed to a total asbestos dose in excess of 25 f/ml years for an asbestosis compensation to succeed if they were not employed in an industry where there was likely to be a high level of regular exposure.

A claim for pleural thickening, where there is a respiratory disability of between 1 and 3 per cent, may also be considered “significant”. Compensation can be substantial if there is more than a ten per cent disability and causing progressive breathing problems.

Greater health risks to young adults

Another key aspect is the age of the victim when the initial exposures occurred. There is, on average, a long delay of between 30 to 40 years before the onset of typical asbestosis symptoms related to breathing difficulties. In many cases, therefore, the victims would most likely have been at the start of their working life, i.e. in their late teens or early 20s.

Medical research consistently finds a higher degree of susceptibility to contracting asbestos-related diseases when exposure occurs before the age of 30, and the greater health risks to teen and young adults continues to be a focus of research.