A Supreme Court ruling has brought clarity to the long-running debate over the liability of employers for damages payable to employees who contract mesothelioma.

Mesothelioma is an aggressive and fatal cancer of the lining of the lungs and can be caused by inhaling a single speck of asbestos. The disease normally takes decades to develop and by the time that symptoms are evident the prognosis is usually very poor.

Because of the difficulties in ascertaining which employer was responsible for the exposure to asbestos that led to the development of mesothelioma, there have, over the years, been many cases concerning the issue of liability and revisions to the law on liability.

In 2008, so-called ‘trigger litigation’ was begun to clarify the law relating to the liability insurance carried by employers against such risks. At issue was the meaning of the clauses contained in insurance policies, which typically either provided cover at the time the disease was ‘contracted’ or when it was ‘sustained’.

In the Supreme Court, Lord Mance concluded that both terms should be read as meaning the time when the disease was caused (i.e. when the worker was exposed to the toxic substance), not when the symptoms first manifested themselves.

The ruling has clarified the position for claimants and insurers alike. However, there will still be many potential claimants who cannot claim damages from their former employers because the latter have gone out of business without records having been retained that would enable their insurers to be identified.

The ruling has potential ramifications for other types of industrial injury which have a long period of latency between the exposure to the agent causing the damage and the manifestation of the injury.