McGhee v National Coal Board [1973] 1 WLR 1 (HL)

Facts

The claimant was employed by the defendant and worked in brick kilns in extremely hot and dusty conditions. His work exposed him to brick dust, which could cause dermatitis. The employer was in breach of duty for failing to provide adequate washing and showering facilities at the workplace.

As a result, the claimant had to cycle home covered in brick dust before washing, thereby prolonging his exposure. He subsequently developed dermatitis. Medical evidence could not determine whether the disease was caused during working hours (which involved non-negligent exposure) or during the extended period of exposure caused by the employer’s breach.

Scientific uncertainty meant the claimant could not prove, on the balance of probabilities, that the failure to provide washing facilities had caused the condition.

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Issue

Can a claimant establish causation where the defendant’s breach materially increased the risk of injury, but it is scientifically impossible to prove that the breach actually caused the harm?

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Decision

The House of Lords held in favour of the claimant. It was sufficient that the employer’s breach had materially increased the risk of dermatitis. In the circumstances, this was treated as sufficient to establish causation.

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Legal Principle

Where a defendant’s breach of duty materially increases the risk of a particular injury, and scientific uncertainty makes precise causation impossible to prove, the court may treat the increase in risk as sufficient to satisfy causation. The case laid the groundwork for the later development of the Fairchild principle.

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Importance

• Introduces the concept of “material increase in risk” in causation.

• Marks an important relaxation of strict “but for” causation.

• Forms the doctrinal foundation for Fairchild and mesothelioma litigation.

• Demonstrates judicial willingness to respond to evidential injustice caused by scientific uncertainty.