McGhee v National Coal Board is a landmark case in UK tort law, decided by the House of Lords in 1972. The case significantly shaped the understanding of causation in negligence, particularly in circumstances where scientific proof of causation is complicated by multiple potential causes.
This decision clarified the test for factual causation by introducing the concept that a breach of duty which materially increases the risk of injury may satisfy the requirement of causation. This case remains pivotal in negligence claims involving cumulative exposure or multiple causes of harm.
Facts of McGhee v National Coal Board
The claimant, James McGhee, was employed by the National Coal Board and was tasked with cleaning brick kilns. During the course of his employment, McGhee contracted dermatitis, a skin condition caused by prolonged exposure to harmful substances, in this case, coal dust. The defendant, the National Coal Board, had failed to provide proper washing facilities at the workplace. As a result, McGhee was unable to wash off the accumulated dust immediately after his shift.
Instead of washing at work, McGhee cycled home each day covered in the harmful brick dust. This prolonged exposure was significant because medical evidence suggested that the longer the skin was exposed to the irritant, the greater the likelihood of developing dermatitis. The employer’s failure to provide washing facilities thus increased McGhee’s risk of injury.
Scientifically, it was impossible to determine whether McGhee’s dermatitis was caused solely by exposure to the dust during working hours or whether the increased exposure while cycling home without washing also contributed. Despite this uncertainty, McGhee sued the National Coal Board for negligence, alleging that the employer’s breach of duty to provide washing facilities caused his skin condition.
Legal Issue
The core legal issue in McGhee v National Coal Board was whether the employer could be held liable for the injury when it was scientifically impossible to prove that the breach of duty was the sole cause of the dermatitis. More specifically, the question was:
- Could the claimant establish factual causation, despite multiple possible causes of the injury?
The traditional test for causation in negligence—the ‘but for’ test—requires the claimant to prove, on the balance of probabilities, that the harm would not have occurred ‘but for’ the defendant’s breach of duty. However, where multiple factors contribute to injury, this test may fail because it is impossible to isolate which cause was the decisive one. The House of Lords in McGhee v National Coal Board was asked to reconsider this approach.
Decision and Reasoning in McGhee v National Coal Board
The House of Lords unanimously ruled in favour of McGhee, holding that the defendant’s breach of duty did cause the injury. The court reasoned that the failure to provide washing facilities materially increased the risk of harm to McGhee, and this increase in risk was sufficient to establish causation.
Lord Reid, delivering a key judgement, explained that dermatitis was a cumulative condition. The longer a worker’s skin was exposed to the irritant brick dust, the more likely it was to develop the disease. The inability to wash immediately after work—due to the defendant’s negligence—meant that McGhee was exposed for a longer period, thus materially increasing the risk of contracting dermatitis.
The court departed from the strict ‘but for’ causation test by holding that where a breach of duty materially increases the risk of injury, this could be equated with a material contribution to the harm itself. Consequently, the defendant’s failure was regarded as having caused McGhee’s dermatitis on the balance of probabilities, even though it could not be proven scientifically that the breach was the only cause.
Legal Principle Established
McGhee v National Coal Board is widely cited for establishing a more flexible approach to factual causation in negligence law. The key legal principle derived from this case is:
- Where a defendant’s breach of duty materially increases the risk of harm to the claimant, this increase in risk may satisfy the causation requirement in negligence.
This principle is often summarised as the ‘material increase in risk’ test. It allows claimants to succeed where the strict ‘but for’ test would otherwise fail, particularly in cases involving cumulative exposure or multiple potential causes.
The case effectively recognised that in situations where scientific certainty is impossible, the law can rely on the practical reality of increased risk to attribute liability. This was seen as a necessary adaptation to prevent injustice to claimants.
Conclusion
McGhee v National Coal Board fundamentally reshaped the law on causation in negligence claims. By recognising that a breach of duty which materially increases the risk of injury can be regarded as causing that injury, the House of Lords made the law more just and adaptable to complex factual scenarios.
The case emphasises the practical realities faced by claimants who suffer harm due to multiple potential causes and scientific uncertainty. It also underscores the principle that defendants cannot evade liability simply because it is impossible to prove exactly which exposure caused the injury.
In sum, McGhee v National Coal Board remains a vital precedent in UK tort law and is essential reading for understanding the development of causation principles in negligence.
