Skin prick tests revealed they had become sensitised to platinum salts as a result.
In accordance with a collective agreement between the Appellants’ trade union and Johnson Matthey, the Appellants were either redeployed to another work environment or, if that was not possible, dismissed with an additional payment by way of compensation. If the Appellants had continued to be exposed to platinum salts, which are found only in specialist workplaces, there was a risk of them developing an allergy. However, an allergy or other symptoms would not develop (or be at risk of developing) if there was no further exposure.
Although no physical symptoms developed, the Appellants had all suffered a significant loss of earnings as a result of no longer being able to perform their original, higher-paid duties. The High Court and the Court of Appeal held that because the sensitisation was asymptomatic and the change in workplace meant it would not develop into an allergy, there was no physical injury capable of giving rise to damages in tort. Without injury, the claim for pecuniary loss was one for pure economic loss.
The Supreme Court unanimously allowed the appeal. It rejected Johnson Matthey’s argument that sensitisation simply resulted in a benign antibody that did not damage the Appellants’ health or physical capability. The Court held that the physiological changes were “undoubtedly” harmful, despite the lack of symptoms, because the Appellants’ bodily capacity for work had been impaired and they were therefore significantly worse off – their bodies were no longer fit for work in areas where they may be exposed to platinum salts.
This case was distinguished from Rothwell v Chemical & Insulating Co Ltd  AC 281, which concerned the development of pleural plaques, as pleural plaques did not lead or contribute to any condition which would produce symptoms even of there was further exposure to asbestos dust.
Whether a person has suffered material damage by any physical changes to their body such that it amounts to an actionable personal injury remains a question of fact, but the Supreme Court has clarified the principles.