Product Liability Lawsuits: Design Defect, Manufacturing Defect, and Failure to Warn

A Doctrine Built on One Core Principle

In 1963, the California Supreme Court's decision in Greenman v. Yuba Power Products transformed American consumer law by establishing that a manufacturer is strictly liable when a product it places in commerce proves defective and causes injury — regardless of whether the manufacturer exercised reasonable care. Before that ruling, injured consumers had to prove fault. After it, proof of defect alone was sufficient. That single shift has produced tens of thousands of lawsuits annually and prompted safety improvements in everything from car seatbelts to children's toys.

Today, product liability law encompasses three distinct theories: design defect, manufacturing defect, and failure to warn (also called marketing defect). A successful claim may rest on one or more of these theories depending on the nature of the product and the injury.

Three Theories of Defect

Design Defect: Two Tests Courts Apply

Courts use two competing standards to evaluate whether a design is defective.

The Consumer Expectations Test asks whether the product performed as safely as an ordinary consumer would expect when used in an intended or reasonably foreseeable manner. This standard is more favorable to plaintiffs because it does not require proof of a safer alternative design.

The Risk-Utility Test (also called the Barker test in California) weighs the utility of the product's design against the severity and probability of harm, the cost of an alternative design, and whether a reasonable alternative design existed. This approach is more common in federal courts and requires expert testimony comparing the challenged design to available alternatives.

Who Can Be Sued in the Distribution Chain

Strict liability extends beyond manufacturers. Under the Restatement (Third) of Torts: Products Liability, any commercial seller in the distribution chain can be held liable:

• Raw material suppliers: If defective materials contribute to the end product's failure.
• Component part manufacturers: If a defective sub-assembly (e.g., a faulty airbag inflator) causes harm independent of the final product's design.
• Assemblers and manufacturers: Primary defendants in most product liability actions.
• Wholesalers and distributors: May be liable where the manufacturer cannot be located or is judgment-proof.
• Retailers: In strict liability states, even a store that sells a defective product without altering it can face claims.

Blameless retailers often have indemnification rights against manufacturers up the chain, but injured plaintiffs benefit from having multiple potential defendants.

Failure to Warn: Pharmaceutical Litigation

Drug and medical device cases are among the most litigated failure-to-warn claims. The "learned intermediary doctrine" holds that a drug manufacturer satisfies its warning duty by adequately informing the prescribing physician rather than the patient directly. However, this doctrine has exceptions: when manufacturers engage in direct-to-consumer advertising, the duty to warn may extend to patients themselves.

Inadequate warnings account for billions in annual pharmaceutical settlements.

Courts examine whether the warning was prominently placed, written in understandable language, and updated to reflect post-market safety data. The FDA's Black Box Warning — the most serious warning it requires — is central to many pharmaceutical liability trials.

Defenses Available to Manufacturers

• State of the art: The product was designed using the best technology available at the time; plaintiffs counter that known risks still demand warnings.
• Comparative fault: The plaintiff misused the product in an unforeseeable way. Most states reduce damages proportionally rather than barring recovery entirely.
• Assumption of risk: The plaintiff knowingly and voluntarily used a product with known dangers (e.g., continuing to use a chainsaw after observing a loose guard).
• Statute of limitations/repose: Product liability statutes of limitations typically run 2–4 years from injury discovery. Separate statutes of repose bar claims arising from products sold more than a defined period (often 10–12 years) before the lawsuit.
• Federal preemption: When a product complies with federal safety standards (notably FDA-approved drug labeling), some courts find state failure-to-warn claims preempted. The Supreme Court's 2009 ruling in Wyeth v. Levine rejected broad preemption for most brand-name drugs but preserved it for generic drugs' failure-to-warn claims in PLIVA v. Mensing (2011).

Damages and Major Settlements

Compensatory damages include medical costs, lost income, pain and suffering, and loss of consortium. Punitive damages are available when the manufacturer knew of a defect and concealed it — the standard applied in landmark tobacco, asbestos, and opioid litigation.

This article is for informational purposes only and does not constitute legal advice.