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Design Defects- Module 2 of 5

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Module 2: Design Defects

Design Defects vs. Manufacturing Defects

Product liability is the area of law governing liability for products that are defective, and that, as a result, cause economic loss or physical harm to the users of such products. Defective design is an important subset of products liability law. A product can be defective either due to an error in the manufacturing process, or because the very design of the product makes it potentially dangerous for the user.

Defects that belong to the first category, manufacturing defects, are proven by comparing how the product that caused the harm was produced with how it was supposed to be produced. If the product does not conform to proper manufacturing standards, and this error in the manufacture makes it dangerous, the seller can be liable for injuries caused by the defective product. However, the second type of defect, a design defect, occurs when the product is unreasonably dangerous despite being manufactured properly.

To understand the difference, compare the facts of two cases. In the first case, the plaintiff sued a car-dealer for selling a car with defective spokes, leading to an accident. She sued on the theory that the car she purchased did not meet the standards for the proper manufacture of that type of car. [1] In the second case, a forklift operator sued when the forklift he was operating experienced a power surge, knocking him to the ground, causing serious injury. He did not claim that the forklift was manufactured incorrectly. Rather, the plaintiff argued that the manufacturer should be liable because the forklift was designed without a seat for the operator to sit on, making it dangerous to operate.[2]  The case rested on the theory that the design of this type of forklift was itself the defect. So, unlike the case of a manufacturing defect, the plaintiff could not prove that the machine that caused his injuries was defective due to flaws in the manufacturing process or by comparison with properly manufactured forklifts.  In these cases, the entire line of products is manufactured uniformly, and would be equally defective.

Design Defect Tests: The Risk-Utility Test

A seller can be liable for a design defect when the product being sold poses risks to the user because of the way it was designed. However, no product is completely without risk, and almost any product can be made safer. If the law allowed for liability any time there was some way of making a product safer, the costs to the manufacturer and the consumer would increase dramatically. So, the law must devise a test that determines when the design is dangerous enough to create liability without driving less expensive products out of the market.

One important approach to addressing design defects is called the risk-utility test. This test balances the risk faced by users of the product against the usefulness of the product as designed, as well as the cost that would be incurred to make it safer. Under the test, the design of a product is defective when the foreseeable risks of harm posed by the product could have been reduced or avoided by using a reasonable alternative design. A manufacturer will be liable if the failure to employ an alternative design makes the product unsafe, assuming that using the alternative design would be reasonable under the circumstances.[3]

The first element of the test requires the plaintiff to show that the risks posed by the defective product were foreseeable.[4] This means that the risks arise when products are used in ways that the seller may reasonably expect.  They are not expected to make products safe for every conceivable circumstance.[5]

For example, in one instance, a child found a beer bottle, smashed it against a utility pole, and a shard of glass from the shattered bottle caused serious injury to his eye.[6] In circumstances such as these, the seller could not be expected to design the product to reduce the risk of injury because the risk was not reasonably foreseeable.

If the plaintiff can make the case that the risk was foreseeable, she must still establish that the risk could have been mitigated in a reasonable way. This reasonable design alternative is the second element of the risk-utility test. The reasonable design alternative has two components. First, the plaintiff must show that an alternative design would pose less risk than the allegedly defective design. . In addition, she must demonstrate that using the safer alternative design would be reasonable for the manufacturer. This reasonability test depends on the level of risk posed by the product, the utility of the product for society, and the cost involved in adopting the alternative design.

Let’s begin with the question of what constitutes an alternative design. This inquiry is complex and involves economic and technological factors. First, note that the law does not require the plaintiff to produce a prototype of an alternative product to make the case for liability.[7] Instead, plaintiffs generally bring evidence from similar products on the market produced by other manufacturers. If it can be shown that other products already on the market serve a similar function at lower risk and at comparable cost, this is a strong basis for establishing a safer alternative design.[8]

The key legal question will often be which products are considered similar enough to serve as a basis for comparison. In Tyson v. General Motors, a court rejected the claim that a two-door, hardtop car was defective on the grounds that the roof was designed without the robust safety features of an earlier version of the car. The court’s rationale was that the earlier model was a full frame, four-door sedan, and so could be expected to have different methods of manufacture with different types of risks than the later model.

Even though the accident was considered a foreseeable risk, and the court agreed that the car would have been safer if the manufacturer had used a different support infrastructure, evidence from another type of product could not be used to show the existence of an alternative design.[9]  Note that while the existence of similar products on the market with a safer design can be persuasive evidence of a reasonable alternative design, the plaintiff is not required to submit such evidence. The standard only requires that such an alternative is a practical possibility. So, the fact that a proposed alternative design has not been adopted by other manufacturers and is not available in the market does not preclude a finding that there was a reasonable alternative design.[10]

At the same time, the defendant can rely on industry standards as evidence that no alternative was practical when the product was offered for sale. This is known as the state of the art defense. A design will not be considered defective if the defendant can show that the available technology and the state of the market did not allow for a safer product at the time of manufacture.[11]

In addition to showing that a product of similar cost and similar model or function could be designed to be less risky, the plaintiff must also demonstrate that it would have been reasonable for the manufacture to employ the proposed alternative design. In practice, safety mechanisms are often marketed as features of products being offered for sale. A seller can ask a higher price for products with these features because they are less risky.

Alternatively, some products that pose risks to users because of their design are also highly useful due to that same design. In those cases, the only way to increase the level of product safety would be to decrease its usefulness. This is why cost and utility are essential to determining the reasonableness of an alternative design. It may not be reasonable to require that manufacturers add safety features if the result is higher costs to the consumers or less valuable products.

Consider an example:

A police officer wearing a bullet-proof vest was shot and killed at a traffic stop when a detained person fired at him. The bullets struck him along the side of his body, which was not covered by the vest. The family of the officer sued the manufacturer of the bullet-proof vest, claiming that the design of the vest left the side of the body exposed to gunfire. They brought evidence of another, larger vest, that completely wrapped around the body, to show that a reasonable alternative design existed.

However, the safer vest was costlier. Furthermore, evidence showed that officers often chose the vest that covered less of the body because the more expensive wrap-around vest was also less flexible and more confining and did not dissipate the heat as well as the smaller vest.[12]

In such a case, the defendant has a strong case to argue that the bulkier, more expensive vest is not a reasonable alternative to the more flexible and cheaper vest. Instead, these should be seen as two competing products, each with their own costs and benefits.

To determine whether a product is defective due to a reasonable alternative design, courts employing the risk-utility test will look at factors such as:

a) the gravity of the danger posed by the challenged design;

b) the likelihood that such danger would occur;

c) the mechanical feasibility of a safer alternative design;

d) the financial cost of an improved design; and

e) the adverse consequences to the product and to the consumer that would result from an alternative design.[13]

Alternative Approach: The Consumer Expectation Test

While the risk-utility balancing test is the standard approach to design defects, it is important to note the consumer-expectation test, which is an alternate approach that may be used in place of, or along with, the risk-utility test. Under this test, a product may be defective if it fails to perform as safely as an ordinary consumer would expect when used in a reasonably foreseeable manner. Specifically, a manufacturer can be liable if the product is dangerous to an extent beyond what the ordinary consumer who purchases it would contemplate.[14]

The consumer expectation test uses a standard of ordinary knowledge common to the community regarding the characteristics of the product in question.[15] However, determining how a device should function and what design would make it safe often involves complex questions of technology and economics. In many cases, these are questions that most people are not in position to answer. So, the consumer expectation test has generally been limited to cases in which the design defect is obvious and apparent to most average users.[16]


Finally, under certain circumstances, some products are so unsafe that the law may hold the defendant liable even if there are no reasonable alternative designs that would make the product safer. These products are sometimes referred to as unavoidably unsafe. The rationale is that these products are so unsafe that the risks they pose will always outweigh any utility they may have for society.


One case in which a product was determined to be unavoidably unsafe involved certain above-grounds pools. These pools were deemed so hazardous that they should be considered defective, even if there was no way to make them safer.[17] Another example often considered to be in the unavoidably unsafe category are realistic-looking toy guns that shoot rubber bullets. Such devices will be considered defective even if every effort is exhausted to make them as safe as possible.[18]


Prescription Drugs and Medical Devices


One special and timely aspect of design defects law is that of liability for defective prescription drugs and medical devices. The law treats the area of medicine differently from the rest of product liability because it presents a unique set of risks and benefits. In medicine, what may be helpful for some can be harmful for others, and vice versa.


This means the usual risk-utility analysis must be considered differently when dealing with a product that has great utility for society, while posing serious risks at the same time. If the law imposed broad liability due to the risks medical products posed to some, it would prevent the use of these products by others for whom they are greatly beneficial. For this reason, the standard for establishing liability in these cases is higher than for non-medical products.[19]


The standard adopted by a highly influential torts treatise is that prescription drugs and medical devices will not be considered to have design defects if they have significant benefits for any class of patients, even while posing serious risk of harm to other patients.[20]


To succeed in a case for design defect, it must be shown that the foreseeable risks so far outweigh the benefits that reasonable healthcare providers would not prescribe the drug or device to any class of patients.[21] According to this approach, legal liability for risky drugs or medical devices that nevertheless contribute to positive health outcomes in any way would be highly unusual.[22]


Note, however, that this demanding standard has not been adopted universally. Some have maintained that the risk-utility test is applicable to drug and medical devices cases as well. In one case, the court rejected the argument that a drug manufacturer was categorically exempt from liability for complications arising from the use of a high blood pressure drug, since the medication had clear benefits for at least some patients.[23]


Even when the high standard does limit liability for design defects, there are other means of preventing unreasonably dangerous drugs and medical devices from reaching consumers. Prescription drugs and medical devices are regulated the by the Food and Drug Administration, which is a federal agency. One reason that courts are reluctant to find liability when a class of patients benefits from a risky medical product is because they tend to defer to the FDA to determine the risks and potential harms of a product.[24]


In this vein, some jurisdictions have passed legislation that recognizes a regulatory compliance defense to claims of design defects. This legislation absolves drug companies of liability for defective medical products if the drug or device in question has been approved for use by the FDA.[25]


Finally, the law imposes an obligation to warn health care providers of foreseeable risks associated with prescription drugs and medical devices.[26] The duty to warn is primarily a duty to inform a physician or other health care provider of the potential harms of products they may prescribe to their patients. Most product liability cases for prescription drugs are decided based on the adequacy of the warning. Note, however, that failure to warn will only create grounds for liability if the warning would have impacted a physician’s decision to prescribe a drug.


In one case, the widow of a depressed patient who committed suicide after taking an anti-depressant sued the drug manufacturer. The plaintiff argued that the manufacturer failed to warn the prescribing physician of the suicidal tendencies associated with the drug. The court dismissed the action, relying on the fact that the physician in question was familiar with the risks of the drug when he prescribed it. Thus, there was no evidence that the physician would have behaved differently if a warning had been provided.[27]


This segues into our next module, wherein we will look at the duty to warn that applies to other products as well as prescription drugs.


[1] MacPherson v. Buick Mfg. Co., 217 N.Y. 382, 111 N.E. 1050, 142 A.D.2d 567 (1916).

[2] Prentis v. Yale Manufacturing Co., 323 N.W.2d 444, 116 Mich. App. 466 (Ct. App. 1982).

[4]  Restatement (3rd) of Torts: Prods Liab., §2(b).

[5]  Restatement (3rd) of Torts: Prods Liab., §2, comment m.

[6] Venezia v. Miller Brewing Co., 626 F.2d 188 (1st Cir. 1980).

[7]  Restatement (3rd) of Torts: Prods Liab., §2, comment f.

[8]  Restatement (3rd) of Torts: Prods Liab., §2, comment f.

[9] Dyson v. General Motors Corporation, 298 F. Supp. 1064 (E.D. Pa. 1969).

[10] Restatement (3rd) of Torts: Prods Liab., §2.

[11] Restatement (3rd) of Torts: Prods Liab., §2.

[12] Linegar v. Armour of America, Inc., 909 F.2d 1150 (8th Cir. 1990).

[13] Barker v. Lull Engineering Co., 573 P.2d 443, 20 Cal. 3d 413, 143 Cal. Rptr. 225 (1978).

[14] Calles v. Scripto-Tokai Corp., 864 N.E.2d 249, 224 Ill. 2d 247, 309 Ill. Dec. 383 (2007).

[15] Restatement (Second) of Torts § 402A, Comment i, at 352 (1965).

[16] Pruitt v. General Motors Corp., 86 Cal. Rptr. 2d 4, 72 Cal. App. 4th 1480 (Ct. App. 1999).

[17] O'BRIEN v. Muskin Corp., 463 A.2d 298, 94 N.J. 169 (1983).

[18] Restatement (3rd) of Torts: Prods Liab., §2, comment e.

[19] Restatement (3rd) of Torts: Prods Liab., §6, comment b.

[20] Restatement (3rd) of Torts: Prods Liab., §6, comment b.

[21] Restatement (3rd) of Torts: Prods Liab., §6(c).

[22] Restatement (3rd) of Torts: Prods Liab., §6, comment f.

[23] Bryant v. Hoffmann-La Roche, Inc., 585 S.E.2d 723, 262 Ga. App. 401 (Ct. App. 2003).

[24] Restatement (3rd) of Torts: Prods Liab., §6, comment b.

[25] See N.J. Code §2A:58C-4.

[26] Restatement (3rd) of Torts: Prods Liab., §6(d)(1)-(2).

[27] Motus v. Pfizer Inc.(Roerig Div.), 358 F.3d 659 (9th Cir. 2004).