To determine if a product is defective under the law, a California judge or jury applies legal tests to the product as it left the company. A manufacturing defect means the unit strayed from its intended design. A design is defective if it fails the consumer expectations or risk-benefit test. Warning defects are non-obvious risks without adequate warnings.
When a product hurts you, the first questions are often personal ones. Was it my fault? Did I use it wrong? A manufacturer facing a claim may raise the same questions.
Those questions come up, but not first. California courts start by looking at whether the product failed a legal standard and whether that failure existed when the product left the defendant’s possession. They also ask whether it was a substantial factor in causing the injury.
What does “defective” mean under California product liability law?
A product is legally defective when it falls short of one of the standards California courts apply to manufacturing, design or warnings. The everyday meaning is looser. A product that broke, or that hurt someone, is not defective for that reason alone.
Some products are dangerous by nature. A kitchen knife is supposed to be sharp, and the danger that comes with a product’s intended purpose is not, on its own, proof of a defect. In Barker v. Lull Engineering Co. (1978) 20 Cal.3d 413, the California Supreme Court described its design-defect test as stopping short of making the manufacturer an insurer for all injuries that may result from the use of its product.
Many California product liability claims rest on strict liability, which looks at the condition of the product rather than at whether the company acted carelessly.
California law generally recognizes three kinds of defects: manufacturing, design and warning defects. We explain each type with examples in our guide to the three types of product defects in California, and a separate post covers how each type of defect affects liability.
How is a manufacturing defect identified?
A manufacturing defect is identified by comparing the product that caused the injury with the product the manufacturer meant to make. California’s civil jury instructions (CACI No. 1202) say a product contains a manufacturing defect if it differs from the manufacturer’s design or specifications or from other typical units of the same product line.
In a manufacturing defect case, the manufacturer’s own design is the yardstick. The question is whether this particular unit came out of production different from its blueprint or from its siblings on the line, so the injured person does not have to show the design was a bad idea. Under CACI No. 1201, the defect must have existed when the product left the defendant’s possession and must have been a substantial factor in causing the harm.
Investigators may use several methods to find that difference:
- Comparing the failed unit with an identical, undamaged unit of the same model, often called an exemplar
- Failure analysis of fractured, melted, cracked or separated parts
- Testing materials and components against the manufacturer’s stated specifications
- Reviewing lot numbers, batch records and production dates
- Requesting quality-control and inspection records through the legal process
Say a metal ladder rung snaps while someone is standing on it. An engineer might start with the ladder itself and compare the weld on the broken rung with welds on other ladders from the same production run. If the failed weld is thinner or incomplete compared with the manufacturer’s specification, that difference may point to a manufacturing defect. If the weld matches the specification, the investigation may shift to whether the ladder’s design was unsafe.
What tests do courts use to decide whether a design is defective?
California courts use two tests for design defects, both set out in Barker v. Lull Engineering Co. A design may be found defective if it fails either one.
Under the consumer expectations test (CACI No. 1203), the jury asks whether the product failed to perform as safely as an ordinary consumer would have expected when used or misused in an intended or reasonably foreseeable way. The Barker court noted that, at a minimum, a product must meet ordinary consumer expectations as to safety to avoid being found defective.
The risk-benefit test (CACI No. 1204) starts with the injured person, who must show that the product’s design was a substantial factor in causing harm. Then the burden shifts to the manufacturer, which must prove that the benefits of the design outweigh its risks. In weighing that question, the jury may consider:
- The gravity of the potential harm from using the product
- The likelihood that the harm would occur
- The feasibility of an alternative safer design at the time of manufacture
- The cost of an alternative design
- The disadvantages of an alternative design
The consumer expectations test has limits. In Soule v. General Motors Corp. (1994) 8 Cal.4th 548, the California Supreme Court said the test is reserved for cases in which the everyday experience of the product’s users permits a conclusion that the design violated minimum safety assumptions. The court observed that the ordinary consumer of an automobile has “no idea” how it should perform in all foreseeable situations. When a design question turns on technical tradeoffs, the jury generally weighs risks against benefits instead.
| Consumer expectations test | Risk-benefit test | |
|---|---|---|
| Question the jury answers | Did the product perform as safely as an ordinary consumer would expect in an intended or reasonably foreseeable use? | Do the benefits of the design outweigh its risks? |
| Who carries the burden | The injured person proves each element | The injured person shows the design was a substantial factor in the harm, then the manufacturer must prove the benefits outweigh the risks |
| When it fits | Everyday experience lets ordinary users form minimum safety expectations | The question involves technical issues of feasibility, cost and design tradeoffs |
| Role of expert witnesses | Experts may not testify about what an ordinary consumer would expect when that is within jurors’ common knowledge | Engineering and design evidence is often central |
When does a missing or inadequate warning make a product defective?
A missing or inadequate warning can make a product defective when the product carried a risk the company knew about or could have known about, ordinary consumers would not have recognized that risk, and the company failed to adequately warn or instruct users about it. Those are core elements of California’s strict liability failure-to-warn instruction, CACI No. 1205.
Whether a risk was “knowable” is measured against the scientific or medical knowledge generally accepted in the scientific community at the time the product was manufactured, distributed or sold. The risk must also present a substantial danger when the product is used or misused in an intended or reasonably foreseeable way.
A warning claim can turn on whether any warning existed, how clearly it was written, where it appeared, and whether the instructions explained how to avoid the danger. A caution tucked deep inside a manual may be weighed differently from a label printed on the product itself. And because one element asks whether ordinary consumers would have recognized the risk, an obvious danger may not require a warning.
Who decides whether a product is defective, and what evidence do they weigh?
The jury decides whether a product was defective, or the judge does in a trial without a jury. The judge also makes an earlier call about which design test fits. According to the directions for CACI No. 1203, the court makes an initial determination of whether the consumer expectations test applies to the product, and in some cases leaves that question to the jury.
Expert testimony often shapes the answer. The Soule court described the risk-benefit question as involving technical issues of feasibility, cost, practicality, risk and benefit. Engineers and other technical witnesses may test the product and review the design choices behind it, then explain possible alternatives to the jury. You can read more about expert witnesses in product liability cases.
The evidence a judge or jury weighs may include:
- The product itself, including broken or separated parts
- Packaging, labels, manuals and instructions
- Design drawings, testing records and internal documents obtained during the case
- Complaints, incident reports and warranty claims involving the same model
- Recall notices and communications with regulators
A recall can be useful evidence, but it is not automatic proof, and a product that was never recalled can still be found defective.
Causation comes last. Each of California’s strict liability instructions for manufacturing, design and warning defects requires proof that the defect was a substantial factor in causing the harm, so a flaw that played no part in the injury does not support a claim.
What can make a product “not defective” in the eyes of the law?
A product may be found not defective, or the company may avoid responsibility, when the injury traces back to something other than a defect that existed when the product left the company’s hands.
The defense may argue misuse, which turns the question “Did I use it wrong?” into the company’s argument. Foreseeable misuse does not excuse the manufacturer, though. Under CACI No. 1245, misuse or modification is a complete defense only if the company proves the misuse or modification was so highly extraordinary that it was not reasonably foreseeable and should be considered the sole cause of the harm. Our post on product defect vs. user error covers that line in more detail.
The company may also point to:
- Alterations made to the product after it left the company’s possession
- Ordinary wear, age or poor maintenance, suggesting the flaw developed after sale
- Obvious risks that ordinary consumers would recognize, which matter most in warning claims
- Evidence that a safer alternative design was not feasible at the time of manufacture or would have created other problems
Shared fault is a separate question, and it does not automatically end a claim. Under CACI No. 1207A, if the company proves the injured person’s own negligence contributed to the harm, that person’s damages are reduced by the percentage of responsibility the jury assigns to them.
Suppose someone removes a blade guard from a power saw and is later injured. The manufacturer may argue the modification caused the injury. The injured person may respond that removing the guard was foreseeable, perhaps because the guard got in the way of common cuts.
What should you do if you think a product that hurt you was defective?
Get medical care first. After that, preserve the product and the records connected to it, because every test described above depends on evidence.
- Get medical treatment and keep copies of your records.
- Keep the product exactly as it is. Don’t repair it, clean it, take it apart or throw it away.
- Think carefully before returning the product to the manufacturer or retailer. Once the product is in the company’s hands, an independent inspection may no longer be possible.
- Save packaging, manuals, receipts and online order history.
- Photograph the product, its model and serial numbers, the place where you were hurt and your injuries.
- Write down what happened while the details are fresh.
- Keep legal deadlines in mind, since they can limit how long you have to file a claim.
For more on these steps, read why it’s important to act quickly after a defective product injury.
This information is provided for general educational purposes and is not legal advice for your situation; whether a product is legally defective depends on the specific facts of each case.
Frequently asked questions
Does a product have to be recalled to be considered defective?
No. A product that was never recalled can still be found defective if it fails a legal test for manufacturing, design or warnings and the defect was a substantial factor in causing the injury. A recall may be useful evidence, but it does not prove that a specific product caused a specific injury.
Can a product still be defective if I didn’t follow the instructions exactly?
It can. California measures design and warning claims by how a product performs when used or misused in an intended or reasonably foreseeable way. Misuse becomes a complete defense only when the company proves the misuse was so highly extraordinary that it was not reasonably foreseeable and was the sole cause of the harm. Shared fault may reduce damages instead.
What if the product was thrown away or sent back to the manufacturer?
Losing the product can make a defect claim harder to prove, especially a manufacturing defect claim that depends on comparing the failed unit with its specifications. It does not always end the inquiry, though. Photos, receipts, model and serial numbers, identical units of the same model and records from the company may still help show what happened.
Do you need an expert witness to prove a product is defective?
Often, yes, especially under the risk-benefit test, which turns on technical questions of feasibility, cost and design tradeoffs. The consumer expectations test works differently. When safety expectations fall within jurors’ common knowledge, California courts do not allow experts to tell the jury what an ordinary consumer would or should expect.
Can a retailer or distributor be responsible for a defective product, or only the manufacturer?
California strict liability can reach more than the manufacturer. The state’s civil jury instructions apply to a defendant that manufactured, distributed or sold the product. In Soule v. General Motors Corp., the California Supreme Court stated that a manufacturer, distributor or retailer is liable in tort if a defect in the manufacture or design of its product causes injury during reasonably foreseeable use.
How we can help
If a product injured you or someone in your family, the question of whether it was legally defective usually starts with the product itself and the records around it. At Hayes Law, attorneys Jillian Hayes and Jim Hayes can review how the injury happened and talk through which legal test may apply to your product.
Both of our attorneys defended insurance companies before representing injured people. We are a small firm by design, so you work directly with your attorneys, and we prepare every case as if it is going to trial.
You can read more about how we handle product liability cases in San Diego. To talk about what happened, call us at 858-737-3311 or contact Hayes Law to schedule a free consultation.