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Why McGhee v National Coal Board is important

In McGhee v National Coal Board, the House of Lords concluded that materially contributing to the risk of injury was equivalent to materially contributed to the harm. This extended the principle outlined by the House of Lords in Bonnington Castings Ltd v Wardlaw.


Mr McGhee worked at a brick kiln where the conditions were very hot, leading to the workers sweating profusely, and dusty. McGhee cycled home after work, which caused him to sweat further. Shortly after finishing work there, McGhee started to suffer from extreme skin condition and was diagnosed with dermatitis.

The dermatitis was caused by exposure to the dust, which was exacerbated because McGhee was sweating (and thus the pores on his skin bigger). However, the medical evidence at the time could not show whether McGhee’s dermatitis was caused by the continued exposure to dust in the hot and sweaty conditions, or just one particle of dust during the course of exposure.


McGhee brought a claim in the tort of negligence against his employers, the National Coal Board. He argued that they breached their duty to take reasonable care by not providing sufficient showering facilities at the kiln.

The defendant employers attempted to distinguish the House of Lords’ judgement in Bonnington Castings. In Bonnington Castings, the claimant showed that every particle of dust contributed to the injury, and thus the defendant did materially contribute to the claimant’s injury. By contrast, due to insufficient medical knowledge McGhee could not show that every particle of dust caused the injury, or when McGhee contracted the condition. Therefore, the claimant’s dermatitis might have been contracted before he cycled home, in which case the defendant’s negligence would not have been a but-for cause of the injury.


The House of Lords overturned the Court of Appeal’s decision. They held the National Coal Board caused the claimant’s dermatitis, making them liable for damages in the tort of negligence. It was sufficient that the National Coal Board materially contributed to the risk of harm.


The HL rejected the defendant’s distinction between the facts of McGhee and Bonnington Castings. The House concluded there was no difference between the material contribution to an injury and the material contribution to the risk of an injury. In McGhee, the medical evidence could not show exactly when the dermatitis was suffered. However, it did show that the longer the claimant went without washing the dust particles from his skin the higher chance there was of contracting the condition.

Lord Reid said:

The medical evidence is to the effect that the fact that the man had to cycle home caked with grime and sweat added materially to the risk that this disease might develop. It does not and could not explain just why that is so. But experience shews that it is so. Plainly that must be because what happens while the man remains unwashed can have a causative effect, though just how the cause operates is uncertain.

Justifying this broad view of causation

Lord Wilberforce justified relaxing the approach to causation based on a number of contextual factors:

First, it is a sound principle that where a person has, by breach of a duty of care, created a risk, and injury occurs within the area of that risk, the loss should be borne by him unless he shows that it had some other cause. Secondly, from the evidential point of view, one may ask, why should a man who is able to show that his employer should have taken certain precautions, because without them there is a risk, or an added risk, of injury or disease, and who in fact sustains exactly that injury or disease, have to assume the burden of proving more: namely, that it was the addition to the risk, caused by the breach of duty, which caused or materially contributed to the injury?

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