Introduction
The case of Dryden v Johnson Matthey plc [2018] UKSC 18 marks an important step in the legal understanding of actionable damage, particularly in the context of occupational health and safety. The central issue before the UK Supreme Court was whether "sensitization" or asymptomatic physiological changes could constitute actionable damage under English tort law. The claimants, employees of Johnson Matthey plc, had been exposed to platinum salts during their employment, leading to sensitization—a condition that rendered them unable to continue working in environments where platinum salts were present. Although the claimants exhibited no immediate symptoms, the court was tasked with determining whether the physiological changes alone were sufficient to establish a cause of action in negligence.
The legal principles at stake included the definition of damage in tort law, the line between actionable harm and mere risk of harm, and how these principles apply to cases involving occupational exposure to hazardous substances. The judgment clarified that actionable damage does not require the appearance of symptoms or functional impairment; rather, physiological changes that limit an individual's ability to work or expose them to future harm may be enough. This ruling has wide implications for employers, employees, and legal practitioners, particularly in industries where exposure to hazardous substances is a known risk.
Legal Background and Context
The case arose in the context of occupational exposure to platinum salts, which are used in the production of catalytic converters. Platinum salts are known to cause sensitization, a condition where the immune system becomes highly reactive to the substance. Sensitization can lead to allergic reactions, such as asthma or dermatitis, upon later exposure. However, in the claimants' case, sensitization had not yet progressed to symptomatic disease. The claimants argued that the mere fact of sensitization was actionable damage, as it restricted their ability to work in environments with platinum salts and increased their risk of future harm.
The legal framework for such claims is based on negligence principles. To show liability, a claimant must prove that the defendant owed a duty of care, breached that duty, and caused actionable damage. The key question in Dryden was whether sensitization, without symptoms, could satisfy the requirement of actionable damage. Earlier case law had indicated that mere exposure to risk, without actual harm, was not enough to support a claim. However, the claimants maintained that sensitization was a genuine physiological change, separate from a simple risk.
The Supreme Court's Analysis
The UK Supreme Court, in a unanimous decision, held that sensitization amounted to actionable damage. The court emphasized that the physiological changes linked to sensitization were not theoretical risks but real alterations to the claimants' bodies. These changes had practical effects, as they stopped the claimants from continuing their employment in settings with platinum salts. The court rejected the argument that actionable damage required the appearance of symptoms or functional impairment, noting that such a requirement would weaken the protective role of tort law.
The judgment relied on established principles of tort law, including the distinction between damage and risk. The court referred to Rothwell v Chemical & Insulating Co Ltd [2007] UKHL 39, where pleural plaques caused by asbestos exposure were not deemed to be actionable damage because they were asymptomatic and did not affect lung function. However, the court differed from Rothwell by pointing out that sensitization, unlike pleural plaques, had immediate practical impact on the claimants' ability to work.
Implications for Employers and Employees
The ruling in Dryden v Johnson Matthey plc has significant implications for employers and employees in industries where exposure to hazardous substances is a known risk. Employers must now account for not only the risk of symptomatic disease but also the chance of asymptomatic physiological changes that could limit employees’ ability to work. This may require stricter compliance with health and safety regulations, including regular monitoring of employees’ exposure levels and the use of preventive measures.
For employees, the judgment provides a clearer path for bringing claims in cases of occupational exposure. The acceptance of sensitization as actionable damage means that employees do not have to wait for symptoms to present themselves before seeking redress. This is especially important in sectors where the interval between exposure and disease can be long, such as asbestos-related illnesses.
Broader Legal and Policy Considerations
The decision also raises broader questions about the range of actionable damage in tort law. By recognizing asymptomatic physiological changes as actionable, the court has expanded the scope of what is considered harm. This has implications for other areas of law, such as environmental torts, where plaintiffs may pursue compensation for exposure to pollutants that result in physiological changes without immediate symptoms.
From a policy viewpoint, the judgment shows the importance of preventive measures in occupational health and safety. By holding employers accountable for asymptomatic harm, the court has spurred earlier risk management. This aligns with the wider approach in health and safety regulation, which increasingly emphasizes prevention over later correction.
Conclusion
The decision in Dryden v Johnson Matthey plc [2018] UKSC 18 clarifies the legal interpretation of actionable damage. By acknowledging sensitization as actionable harm, the UK Supreme Court has confirmed that physiological changes—even in the absence of symptoms—can form the basis of a negligence claim. This outcome has notable consequences for employers, employees, and legal professionals, particularly in fields involving known exposure to hazardous substances. It also prompts questions about the limits of actionable damage and the function of tort law in supporting preventive health and safety measures.
The case is a reminder of the changing nature of tort law and its capacity to adjust to new scientific and medical knowledge of harm. As industries continue to change, so must the legal frameworks that guide them. The judgment in Dryden shows the court's commitment to ensuring that tort law remains a strong and effective means of protecting individuals from harm.
