Mesa AZ | Personal Injury and Product Liability

Products liability is a unique sector of the law that has its own set of rules and practices. If you are considering a personal injury case based on products liability, you should carefully study the ins-and-outs of product liability law and familiarize yourself with how these cases typically proceed. To that end, we are providing a multi-part series of blogs on the subject. This is Part 2, which covers what makes a product defective and unreasonably dangerous.

To win his or her product liability case, a plaintiff must prove that the defendant manufactured or sold a product that was defective and unreasonably dangerous, and that the defect caused the plaintiff’s injury. Knowing this, a potential plaintiff might wonder what, exactly, defective and unreasonably dangerous means. The best answer, as is often the case with matters of law, would be “it depends.” It depends on what type of product defect the plaintiff is trying to prove in his or her specific case.

Arizona provides for three separate types of product defect: manufacturing defect, design defect, and information defect. Each has its own definition, which a jury will use to decide the case. A potential plaintiff should learn about each one and then determine which best fits the facts of his or her case. Once that is determined, the plaintiff can begin to prepare evidence to convince the jury that there was a manufacturing, design, or information defect. Following below are the definitions of each type of defect – manufacturing, design, and information – and a brief explanation of each. The definitions are derived from Arizona’s Revised Civil Jury Instructions.

Manufacturing Defect

            A product is defective and unreasonably dangerous because of a manufacturing defect if it contains a condition which the manufacturer did not intend and, as a result, it fails to perform as safely as an ordinary consumer would expect when the product is used in a reasonably foreseeable manner.

            There are three distinct parts to this definition – three requirements that must be met before a jury can find that the product in question had a manufacturing defect.

         First, the product must have a “condition that the manufacturer did not intend.” In other words, there must something about the product as it rolled off the assembly line that makes the product different than the manufacturer intended it to be.

Second, the condition must cause the product to fail to “perform as safely as an ordinary consumer would expect.” So, the condition must not only change the product from what the manufacturer originally intended, it also has to change the way the product works. It has to make the product less safe for the ordinary consumer. Notice that this is an objective standard – the jury will be imagining a hypothetical ordinary consumer, not basing its ruling on the plaintiff’s subjective ideas about who an ordinary consumer for the product might be. This means that the plaintiff must present objective evidence about the ordinary consumer of the product in question.

Finally, the jury will evaluate all of this in the light of the “reasonably foreseeable use of the product.” In other words, if the jury is evaluating a fork, it is going to be thinking of the reasonable foreseeable uses of the fork, such as use as an eating utensil. The jury will only find that a product was not safe due to a manufacturing defect if it was not safe within its realm of reasonable uses.

Design Defect

The Revised Civil Jury Instructions provide for two different definitions for a design defect. That first states that:

A product is defective and unreasonably dangerous because of a design defect if the harmful characteristics or consequences of its design outweigh the benefits of the design.

This sets out a balancing test: the jury must evaluate the design of the product and determine what (if any) aspects of that design might have made the product dangerous or given the product negative, harmful consequences. The jury must then weigh the negative of the design with the positive, and essentially decide whether the negative was worth the risk. If the negative outweighs the positive in this manner, than the design was defective. The Revised Civil Jury Instructions put it this way: “If you find that it would not be reasonable for a manufacturer or seller…to have put this product on the market without changing the design, then the product is defective and unreasonably dangerous because of a design defect.”

It is apparent from the above that the plaintiff will have to provide the jury with detailed, specific information on the product’s design that especially focuses on the design’s negative aspects. This can be a complex and difficult task that will require extensive preparation.

The second definition provided by the Revised Civil Jury Instructions reads as follows:

A product is also defective and unreasonably dangerous because of a design defect if it fails to perform as safely as an ordinary consumer would expect when the product is used in a reasonably foreseeable manner.

This is quite similar to the requirements for a manufacturing defect. The jury will evaluate the intended use of the product and any reasonably foreseeable use, and then determine whether its performance in the case of the plaintiff was unsafe in light of such reasonably foreseeable use.

Information Defect

A product, even if faultlessly made, is defective and unreasonably dangerous if it would be unreasonably dangerous for use in a reasonably foreseeable manner without an adequate warning or instruction.

These days, most products come packaged with various warnings and instructions. These typically say things like, “WARNING – Do not use this product near an open flame.” Such warnings and instructions are the subject of information defects. If a product comes with no such warnings or instructions, a jury could find that it was defective and unreasonably dangerous.

Once again, this definition includes the reasonably foreseeable use limitation. A product’s warnings and instructions must only cover reasonably foreseeable uses – manufacturers do not need to worry about warnings related to unreasonable or unforeseeable uses of the product.


The above is meant to provide only a brief overview of the three separate definitions of a defective and unreasonably dangerous product. Potential plaintiffs should consult a qualified, experienced attorney for more information and for advice on which of the three the plaintiff should target in his or her specific case.

This blog should be used for informational purposes only. It does not create an attorney-client relationship with any reader and should not be construed as legal advice. If you or someone you know wishes to seek the help of an experienced personal injury attorney regarding Product Liability: Defective and Unreasonably Dangerous, or other personal injury matters, call 480.461.5300. Udall Shumway PLC is located in Mesa, Arizona and is a full service law firm. We assist Individuals, families, businesses, schools and municipalities in Mesa and the Phoenix/East Valley.