Manufacturing, design, and warning defects

This is the most straightforward theory, because the benchmark is the manufacturer's own specification. You're not arguing the design should have been different — you're showing this unit departed from what the company itself intended.

Proof comes from examining the product against the specification, which is why preservation matters so much here. Evidence that other units from the same lot failed the same way is strong corroboration.

Courts apply two main tests, and which one your state uses matters. Under the risk-utility test, the question is whether the design's risks outweigh its benefits, usually turning on whether a reasonable alternative design existed that was safer, feasible, and not prohibitively costly. Under the consumer expectations test, the question is whether the product was more dangerous than an ordinary consumer would expect.

The feasible alternative design is usually the heart of it, and it's an engineering argument: someone else was already doing it safer, or the company's own engineers proposed it and were overruled. Internal documents in these cases are often decisive.

The questions are whether the manufacturer knew or should have known about the risk, whether the warning was adequate in content and prominence, and whether an adequate warning would have changed what happened. Buried text in a manual nobody reads is frequently held inadequate where the hazard is serious and the warning could have been placed on the product itself.

There's also a post-sale duty in many states: a manufacturer that learns of a hazard after selling a product may have an obligation to warn owners, which is what recall campaigns partly reflect.

That's meaningfully easier than negligence, and it's the doctrinal reason product cases are viable against companies whose internal conduct you could never otherwise reconstruct. Negligence and breach of warranty claims are usually pleaded alongside it.

The main defenses are that the product was substantially altered after sale, that it was misused in a way that wasn't foreseeable, and comparative fault. Note the word foreseeable — misuse a manufacturer should have anticipated is generally their design problem, not your defense to overcome.