A simple, uniform legal definition of a defective product is impossible across the 50 different state judicial districts and eleven federal districts that comprise our country.
Since we must deal with slightly different definitions of design defect in every state and federal district court, sound general design concepts are probably of more value to the designer than attempts to satisfy legal "definitions," which may be correct in one jurisdiction and incorrect in another.
The "restatement of torts," the personal injury attorney's Bible, provides that a product is unreasonably dangerous and hence defective if the article sold has hazards that the ordinary consumer could not know about with the knowledge common to the community about the product's characteristics. This test is objective and does not depend upon the actual knowledge of the injured consumer.
What is safe? The designer tests are likewise objective; the development of "safe" products is a process much more standardized than the subjective definition of "safe" by a jury. A primary consideration is the "risk/benefit analysis" that provides that a dangerously defective product is one that a reasonable person, knowing of its harmful character, would not sell to the public. Thus, the question is simply whether the manufacturer is negligent by selling the product, knowing the risks involved. For example, concentrate sulfuric acid makes a wonderful drain cleaner and solvent, but is so dangerous in non-industrial settings that risk of harm to a housewife or child far outweighs its superiority as a drain cleaner. Thus, alkali chemicals are more acceptable for home use.
Simply stated, do not design a machine with a pinch point if the item can be made equally effective without endangering the operator's fingers. Charcoal lighter fluid should ignite charcoal but not be ultra-hazardous to people or personal property. These basic examples can and must be extended to the complex products of the '90s. A faulty micro-chip, electrical component, or hydraulic system can endanger a manned space flight. Indeed, the failure of several related products in our defense systems could bring us to the brink of nuclear conflict. Most aviation disasters are precipitated by a combination of design defects and human error.
Anticipate problems. The potential for significant damage or serious injury is a practical yardstick that should be applied to the products you design and manufacture. Use imagination. Not only should products meet or exceed all relevant industry and government codes, regulations, and safety standards, but the design team must try to anticipate any potential factor that might precipitate product failure.
All reasonable possible design alternatives should be evaluated; every foreseeable way that the product might be misused or abused must be identified and the unsafe, potentially hazardous design feature eliminated. If foreseeable dangers cannot be designed out, the conspicuous, clear, comprehensive, permanent warnings must be affixed to the product where feasible, or at least accompany it in the manual.
Anticipation, in the legal sense, is a critical attribute of today's successful designer. The "absent-minded professor" image and approach will result in lawsuits and adverse verdicts related to your products. The engineers of the '90s must develop a basic understanding of product liability litigation, and more specifically, the legal pitfalls of design engineering.
Q What is the legal definition of a product design defect?
A In states following strict liability law, a defective product is one that is defective and unreasonably dangerous to a user when sold. The defect is any deficiency in the product which may cause it to fail and result in injury. Even asbestos has been found defective because of the harm it may cause to human tissue, although no obvious defect is in asbestos.
Q Is a designer or manufacturer under an absolute duty to sell only defect-free products?
A No. However, the law of strict liability holds the manufacturer liable for defects in products which cause harm. The product defect must make the product unreasonably dangerous to the user. If the user is injured but, there is no defect nor is the product unreasonably dangerous the manufacturer is not liable. The defect must be one which the manufacturer/designer knew of or should have known about at the time of sale. If the defect was latent and not discoverable nor reasonably avoidable by the designer, there may be no liability.
Q If I design a component product which is free of any defect, but is later incorporated into a product which is defectively designed? Am I responsible if the product fails?
A No. The component manufacturer will only be held liable when there is evidence that that particular component was defective or unreasonably dangerous. However, it is useful for the component manufacturer to have an indemnification agreement with the final product manufacturer to assume the defense of any lawsuit not caused by the component manufacturer's negligence or breach of warranty.