The length of time that a claimant was exposed to asbestos dust is an important factor when evidence is produced at court to support a mesothelioma claim. A judge will refer to applications of the law by which a decision can be reached.

The verdict may not always go in the claimant’s favour if it is determined that exposure had not exceeded guidelines and there is insufficient evidence to prove that an employer was negligent.

In one recent case, a judge did conclude at an initial hearing that the asbestos exposure time was not “substantial” enough to award mesothelioma compensation.

Not in breach of defendant’s duty of care

The court heard that the employer only required the claimant to work with asbestos on rare occasions and, therefore, was not in breach of his duty of care. The judge’s decision reflected an understanding of asbestos exposure risk based on a guidelines standard set out in 1970, known as HM Factory Inspector Technical Data Note (TDN) 13.

Fixed at a significantly higher level than is the accepted guideline today, TDN 13 exposure times to brown ‘amosite’ asbestos and ‘white’ chrysotile asbestos were as follows:

  • 12 fibres per millilitre as an average over any 10 minute period.
  •   2 fibres per millilitre as an average over any 4 day period.

Under current Control of Asbestos at Work Regulations 2006/12, the control limits are set at:

  • 0.1 fibres per millilitre of air averaged over a continuous period of 8 hours.
  • 0.3 fibres per millilitre of air averaged over a continuous period of 4 hours.

While the above limits are directed towards larger scale works, such as building renovations or demolition, nevertheless, control limits for a shorter duration of asbestos exposure are given as:

  • 0.9 fibres per millilitre of air averaged over a continuous period of 10 minutes.

Exposures did not exceed the 1970 guidelines

The claimant was employed making “one hour” fire check doors containing asbestos insulation board at the defendant’s company between 1973 and 1977. However, the defendant argued that manufacture of doors was rare and did not exceed the 1970 guidelines. The claimant also told the medical examiners that his exposures were limited although, after 40 years, there was some admitted memory issues.

The judge concluded that any exposure to asbestos was most probably less than an hour and, therefore, exposure was unlikely to have exceeded either the short-term limit or the four hour average as set out in TDN 13.

The court did not think that the defendant was in breach of their duty of care in exposing the claimant to asbestos nor was the asbestos-related condition a “reasonably foreseeable” consequence of the exposure. Clearly, the court took the view that as exposure was determined to be neither heavy nor regular, the defendant could not be liable for the claimant’s resulting mesothelioma.

Link to colon cancer

During the 1970s, around 150,000 tons of the low cost insulation was imported annually into the UK despite a growing asbestos awareness to the deadly health risks. Doctors and clinical research had identified asbestos-related diseases, such as asbestosis as far back as the 1920s.

Nevertheless, slowness to put adequate regulations into place simply led to employers ignoring the potential fatal risks. As a result, there was a widespread lack of protection for industrial workers, tradesmen and maintenance crews directly involved in handling asbestos materials.

In the years following the UK ban of asbestos use from the mid 1980s, medical research and government statements have repeatedly issued warnings over white chrysotile. The so-called ‘low level’ risk asbestos is now accepted as a Class 1 cancer-causing substance without a confirmed threshold level, below which, exposure would be considered safe for human health.

There is also medical evidence, which indicates a link between a short-duration exposure triggering colon cancer lesions, while longer term exposures of a short duration can possibly increase the risk of developing gastrointestinal tumours, depending on the fibre dust levels present.

The British Journal of Cancer has also stated that “Asbestos continues to be the cause of the largest proportion of the overall burden of occupational cancer.” Despite mesothelioma accounting for less than 1 per cent of all cancers, around 2,500 people continue to be diagnosed with mesothelioma in the UK every year.