The mass production and consumption of consumer products in the twentieth century presented a considerable challenge to tort law. Negligence law responded to this challenge, and the initial duty to take reasonable care to manufacture products that are free of dangerous defects - recognized in Donoghue v. Stevenson1- has been complemented by a duty to warn of the inherent dangers of products and a duty to design products with reasonable care. Courts have, however, proceeded more cautiously in respect of the duty to warn and to design with care. The reason is that manufacturing defects normally arise in isolated rogue products. The defect is the result of a mistake or malfunction in the defendant’s manufacturing or quality control systems. In practice, therefore, the extent of liability will not normally be unmanageable or overly burdensome. In contrast, liability arising from a failure to warn of inherent dangers or a failure to use reasonable care to design a safe product may condemn a complete line of the defendant’s products and may place undue burdens on manufacturers. This differentiation among the obligations of manufacturers is also reflected, in a different way, in American product liability law. Strict liability is the norm for manufacturing defect cases but, in cases of design flaws and a failure to warn, fault is often required.
The modern law of products liability began with a defective bottle of ginger beer and the case of Donoghue v. Stevenson. Lord Atkin stated:
[A] manufacturer of products, which he sells in such a form as to show that he intends them to reach the ultimate consumer in the form in which they left him with no reasonable possibility of intermediate examination, and with the knowledge that absence of reasonable care in the preparation or putting up of the products will result in an injury to the consumer’s life or property, owes a duty to the consumer to take reasonable care.2This passage outlines the primary obligation of manufacturers. It is to take reasonable care that their products are manufactured in compliance
with their intended specifications and design and that they are not dangerously defective.
Lord Atkin’s formulation of this duty of care was expressed in cautious and guarded terms. His language reflected both the novelty of the case and the state of negligence law at that time. His expression of the scope of the manufacturer’s duty has now been loosened and broadened in almost every conceivable way.
The duty of care extends to all consumer and commercial products, including buildings. The requirement in Donoghue that the product must reach the consumer in the same form in which it left the manufacturer initially gave rise to suggestions that the product must be in a sealed package or bottle. Now it is taken to reflect the normal requirement of cause-in-fact and the need to show that the damage was caused by the manufacturer’s negligence and not by the negligence of some other person or by the normal deterioration of the product through wear and tear. The suggestion, in the case, that the defendant would be protected from liability if the defect could be discovered by an intermediate examination of the product by a third party or the plaintiff reflected the prevailing judicial attitude to intervening acts and to contributory negligence. Today, the failure of a third party, such as a retailer, to discover a defect by reasonable inspection is unlikely to exonerate the defendant. It is more likely that the manufacturer and the third party will be held jointly and severally liable.3A failure by the plaintiff to inspect the product suggests contributory negligence, which was a complete defence when Donoghue was decided. Now damages may be reduced on account of the plaintiff’s fault but the defendant will not be exonerated from all liability.
The duty of care currently extends beyond the manufacturers of products. It rests on the makers of component parts, assemblers, installers, repairers, and building contractors. Liability is restricted to those who may foreseeably be injured by the defective product but it is difficult to imagine a situation where a consumer, a user, or even a non-user of a defective product who is injured by it would not satisfy that test. In his dissenting judgment in Donoghue, Lord Buckmaster feared
that if one step was taken fifty would follow. That has proved to be a conservative estimate.
As yet, however, Canadian courts have resisted the temptation of imposing strict liability on manufacturers of defective products.4This has created a technical inconsistency in product liability law because under contract law the retailer of goods normally gives to the purchaser an implied warranty (guarantee) that the goods are free from defect.5This strict liability of the seller to a purchaser contrasts with the standard of reasonable care of the manufacturer to all those who may foreseeably be injured by his goods. This theoretical disparity between the intensity of the obligations of retailers and manufacturers is, however, minimized in practice by the application of high standards of care against manufacturers, the use of circumstantial evidence (formerly known as res ipsa loquitur), and the principle of vicarious liability of employers for the torts of their employees, all of which conspire to allocate most accident losses caused by defective products to the manufacturers of them.
The expansion of liability that followed Donoghue was fuelled by policies of accident prevention, compensation, and loss distribution. Negligence liability provides some deterrence against the manufacture of dangerously defective products. The liability costs may eventually be passed on to customers but there may be some market deterrence, and manufacturers prefer to avoid the bad publicity that may accompany a finding of liability. The compensatory concerns of plaintiffs also favour the extensive liability of manufacturers who are well placed to spread the loss through the price of the product or liability insurance.
Manufacturers are also under a duty to warn consumers of dangers inherent in the use of their products. The leading decision on the duty to warn is that of the Supreme Court in Lambert v. Lastoplex Chemicals Co.6In that case, the...