In Bussey v Anglia Heating ([2018] EWCA Civ.243, 22 February 2018), the Court of Appeal looked at asbestos exposure levels sufficient to found liability for causing mesothelioma. Mr Bussey had developed mesothelioma as a result of exposure while employed by the defendant as a plumber from 1965 to 1968. The issue was whether, given the relatively low level of exposure and the state of knowledge in the late 1960s, the defendant was under a duty to take protective measures.

At first instance, the judge had regarded himself as bound to follow the decision in Williams v University of Birmingham ([2011] EWCA Civ.1242), in which the Court of Appeal found that Technical Data Note 13 (TDN13) was the best guide to what were acceptable levels of exposure to asbestos in 1974 and that exposure below the levels identified did not give rise to a reasonably foreseeable risk of injury. TDN13 was published by the Factory Inspectorate in 1970 (two years after Mr Bussey’s exposure ended) and addressed standards for dust concentration for use with the Asbestos Regulations 1969.

In Bussey, the Court of Appeal found that Williams should not be read as making TDN13 a universal test of foreseeability in mesothelioma cases. A “more nuanced approach” is required. It is necessary to look at the information which a reasonable employer in the defendant’s position at the relevant time should have acquired and then to determine what risks such an employer should have foreseen. The case was remitted to the trial judge to re-determine the issue of liability in the light of the Court of Appeal’s guidance.

The Court of Appeal had differing views as to the correct formulation of the test for foreseeability. Jackson LJ expressed the test as whether the defendant ought reasonably to have foreseen that the relevant exposure would expose the employee to an unacceptable risk of asbestos-related injury. Underhill and Moylan LJs preferred a formulation that split the test into two parts: should the employer have been aware at any time during the exposure that it gave rise to a significant risk of asbestos-related injury?; and if the employer should have been so aware, did the employer take proper precautions to reduce or eliminate the risk? They thought that to link the test to what was “acceptable” or “unacceptable” was liable to mislead.