Asbestos is certainly a potential cause of lung cancer but around 85% of all lung cancers are believed to be caused by smoking.
However, it is well established that people who smoke and are exposed to asbestos have a much higher risk of developing lung cancer than smokers who were not exposed to any form of asbestos and in one study were found to be around fifty times more likely to contract the cancer in these circumstances than non-smokers.
Asbestos-related lung cancer claims where the victim is a smoker therefore involve complex issues of causation. Where a claimant has smoked and been exposed to asbestos, how does a court decide which of those caused their cancer or to what extent it caused it?
Medical evidence will need to be obtained confirming the asbestos exposure caused or contributed to the development of the lung cancer. Furthermore, it is generally considered that for asbestos to contribute to the development of lung cancer, there has to have been a heavy asbestos exposure and engineering evidence is often needed to assess the level of exposure.
In most asbestos-related lung cancer cases, it is generally accepted that the test to use is whether a claimant’s asbestos exposure, when considered in isolation, more than doubles the risk of developing lung cancer. But even if asbestos is found to have caused or contributed to the development of the lung cancer, the smoking history is not ignored by the Courts.
A recent example of this is the case of Blackmore v Department for Communities and Local Government (2017). Mr Blackmore was exposed to asbestos at the Devonport Dockyard for at least five years, both removing it and sweeping up after others’ activities. It was relatively heavy exposure and his employer’s accepted that they had negligently exposed him to asbestos. He died from lung cancer aged 74 and mineral fibre analysis of the lungs showed a quantity of total retained asbestos fibre count above the level at which the risk of contracting lung cancer doubles.
However, Mr Blackmore was also a moderate but long term smoker, with a 20 a day habit for around 60 years, tailing off a little in his final few years. The defendant’s expert argued that the deceased’s smoking was the overwhelmingly more significant contributor to the risk of his cancer.
Even after disregarding the first 25 years of his smoking (when Mr Blackmore and the rest of society would have been ignorant of the dangers of the habit) the defendants argued that smoking caused 90% of his cancer risk with the remaining 10% due to their negligent asbestos exposure.
They used these figures to argue for a correspondingly huge reduction in any compensation award. The court rejected those arguments.
The judge maintained that the causes of lung cancer cannot be determined by a simple statistical analysis as the defendants tried to do here, but he did find that Mr Blackmore’s smoking was a cause of the cancer, especially when he continued to smoke after the links between smoking and cancer were well established and well known.
However, while his actions in continuing to smoke when he ought to have been aware of the risks were a contributory factor in his succumbing to cancer, his was considered morally ‘less blameworthy’ than the willful disregard his employers showed for his health and safety.
A finding of 30% contributory negligence for smoking was upheld by the Court of Appeal in Mr Blackmore’s case.