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Liability and Defenses to Products Liability

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Stream of Commerce:
The flow of products from manufacturers, suppliers, retailers, distributors and lessors to the consumer.

Case law has established that anybody who causes a product to “enter the stream of commerce” or “passes it on” in the stream of commerce can be held strictly liable for any harm caused by defects in the product. This includes manufacturers, suppliers, retailers, distributors, lessors, assemblers of component parts into finished products and, in some cases, contractors. See Alvarez v. Felker Manufacturing, 230 Cal.App.2d 987 (1964).

All jurisdictions hold that any person injured by a defective product, whether the plaintiff is a purchaser or a bystander, can recover under strict liability. See Codling v. Paglia, 32 N.Y.2d 330 (1973). However, strict liability can only be invoked in situations where the injury is caused by an actual product. That is to say, strict liability will not be invoked where the plaintiff was injured by poorly performed services.This makes a difference because, in a situation where a product is not defective but the plaintiff suffers injury as a result of defendant’s poor installation or servicing of the product, the plaintiff will not be able to invoke strict liability. See Schemel v. General Motors Corp., 384 F.2d 802 (7th Cir. 1967).

In addition, certain jurisdictions allow strict liability against sellers of used products. However, most jurisdictions do not allow strict liability here because it is unreasonable for the buyer of a used product to expect the product to be completely free of defects. Finally, strict liability only applies to people regularly engaged in the business of manufacturing, selling or leasing the defective product. Amateur or occasional sellers of products will not be held strictly liable.

Further, because the product must have been introduced into the stream of commerce for strict liability to be invoked, a plaintiff cannot recover under a strict liability theory if he is injured by a test model that has not been sold.

Please note that although strict liability cannot be invoked in these cases, an ordinary negligence claim is still possible.

Determining Defects

The most difficult question a court has to confront in product liability cases is the question of what exactly makes a product defective. Answering this question depends on two different factors: the type of defect and the standard used to determine the defect.

As we have already discussed, the three types of defects are manufacturing defects, design defects and defects due to lack of warning.

As for the standard used to determine whether or not there is a defect, the general understanding is that a product is defective if it is unreasonably dangerous, i.e., if the defect causes injury other than what a reasonable person would anticipate through the normal use of the product.

Further, the injury to the plaintiff must be the result of the normal or foreseeable use of the product. Please note that normal and foreseeable use does not necessarily mean intended use. A product that poses no risk to a plaintiff when used appropriately may pose a risk when used in a way that it was not intended for. However, if the unintended use was still foreseeable, the defendant could still be liable. For example:

Ethan manufactures office chairs. The chairs are intended, obviously, for people to sit on. Allen stands on the chair in order to change a light bulb and falls. In this situation, if Allen’s fall was caused by the chair slipping or tilting, Ethan could be held liable for Allen’s injuries, even though the chair was not made for people to stand on. 

In this example, standing on the chair is a foreseeable, although not intended, use of the product. The law requires that a manufacturer foresee a certain amount of misuse of its products. That being the case, the law requires that defendants warn plaintiffs of any possible dangers that could be created by such misuse. Alternatively, manufacturers must manufacture the product with safety devices that would protect against these possible harms.

Further, it is foreseeable that a buyer will try to modify a product after he buys it. In such cases, the manufacturer may be liable for the harm caused if the product invited the modification. See Liriano v. Hobart Corp., 92 N.Y.2d 232 (1998). For example:

A snowmobile manufacturer builds his snowmobiles with speed caps that prevent the snow mobiles traveling in excess of 50 miles per hour. The purchaser/plaintiff removes the speed cap so that he can travel at a faster rate of speed. The plaintiff is severely injured when he loses control of his snowmobile traveling at 80 miles per hour. In such a situation, since the snowmobile invited the modification (it is foreseeable that a purchaser would remove the speed cap in order to go faster), the manufacturer may still be liable to the plaintiff.

Where a plaintiff has a highly unusual reaction to a product (like an allergic reaction), the product is not considered defective so long as the plaintiff’s reaction is so unforeseeable that it could not have been guarded against. See Mountain v. Procter & Gamble Co., 312 F.Supp. 534 (E.D. Wis. 1970). However, more and more jurisdictions are adopting the view that, if there is a known risk of harm to any number of potential users, the manufacturer owes a duty to warn potential buyers of the potential risks no matter how few potential users are at risk.


As in ordinary negligence cases, the plaintiff must show that his injuries were caused by a defect in the product that existed at the time the product was sold by the defendant. See Williams v. Ford Motor Co., 494 S.W.2d 678 (Mo. 1973).


The plaintiff can recover for all physical injuries suffered as a result of a defective product, including pain and suffering, medical expenses, loss of income (as a result of a physical injury) and, where applicable, wrongful death. In addition, damage to property is also recoverable in most jurisdictions. However, most jurisdictions do not allow recovery for purely economic loss. 

Defenses to Strict Liability

The plaintiff is under no duty to inspect the product and so his failure to do so will not be a valid contributory negligence defense. However, where the plaintiff is injured due to an unreasonable misuse of a defective product, contributory negligence will be valid and may bar liability. See McDevitt v. Standard Oil, 391 F.2d 364 (5th Cir. 1968).

Comparative negligence is a valid defense. Most jurisdictions that have adopted comparative negligence will reduce the plaintiff’s recovery in these cases to reflect the fact that plaintiff contributed to his own injuries. See Rudisaile v. Hawk Aviation, Inc., 592 P.2d 175 (N.M. 1979).

Finally, assumption of the risk is also a valid defense. A plaintiff who knows the danger of using a certain defective product and continues to use the product anyway may be held to have assumed the risk. However, in order for assumption of the risk to be a viable defense, the plaintiff must have actually known of the particular danger involved in using the defective product and voluntarily continued to use that product anyway. 

Where the plaintiff knows of the potential risks involved in continuing to use a defective product, but has no choice but to continue using the product, assumption of the risk is not available as a valid defense.

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