Products Liability
One injury, five theories. The MBE's favorite move is giving you facts that fit one theory and answer choices quoting the others.
The five theories
| Theory | Who's liable | What plaintiff must show |
|---|---|---|
| Strict products liability | Commercial sellers in the chain—manufacturer, distributor, retailer | Defective when it left D's hands + caused harm; no fault needed |
| Negligence | Anyone careless—including used-goods dealers and service providers | Ordinary negligence: breach in design, making, or inspecting |
| Implied warranty of merchantability | Merchants of goods of that kind | Goods unfit for ordinary purposes—contract-flavored, no fault |
| Fitness for particular purpose | Any seller who knew buyer's special purpose + reliance | Buyer relied on seller's skill to pick the goods |
| Express warranty / misrepresentation | Whoever made the statement | An affirmation of fact about the product, breached |
Strict liability, element by element
(1) Defendant is a commercial seller of the product; (2) the product was defective when it left the defendant's control; (3) it reached the plaintiff without substantial alteration; (4) the defect caused the harm during a foreseeable use—which includes plenty of misuse. No privity required: any foreseeable plaintiff—buyer, family, bystander—may sue any commercial seller in the chain.
Rosa's café espresso machine explodes and scalds customer Lana. Lana can sue the manufacturer AND the distributor AND the dealer—strictly—though not Rosa: serving coffee makes her a service provider, not a commercial seller of machines. And casual seller Liv, who sold her old machine at a yard sale, is out of strict liability entirely.
The three defects
| Defect | The test | 🐚 Example |
|---|---|---|
| Manufacturing | This unit departed from its intended design—more dangerous than consumers expect | One jar in Rosa's salsa run contains glass shards |
| Design | A reasonable alternative design existed—safer, economical, practical—and not adopting it made the line unreasonably dangerous | Noodle Corp.'s space heater tips over and ignites; a $2 tip-switch existed |
| Warning | Foreseeable, non-obvious risks lacked adequate warnings or instructions | Liv's hair serum causes burns when used near heat—nothing on the label |
Match the defect to the proof: manufacturing = compare the unit to its own blueprints (closest to true strict liability); design = the risk-utility fight over the alternative design; warning = adequacy, prominence, and the obviousness carve-out (no duty to warn that knives cut).
Which theory fits the facts?
The sorting questions
Is the defendant a commercial seller of this kind of product?
Negligence (or warranty) only. Casual sellers and service providers are out of strict liability.
Was the product defective when it left this defendant's hands?
No strict liability—later alteration or damage in transit breaks the chain against upstream sellers.
Foreseeable use (including foreseeable misuse)?
Unforeseeable misuse defeats the claim—standing on the top ladder rung is foreseeable; using the mower as a hedge trimmer is not.
Strict liability attaches
Damages for personal injury and property—pure economic loss stays in warranty.
Defenses
Comparative fault: most states reduce recovery for the plaintiff's own unreasonable conduct; ordinary failure to discover the defect is not a defense.
Assumption of risk: knowing of the specific defect and using it anyway.
Unforeseeable misuse or alteration: breaks causation. Disclaimers: ineffective against personal-injury strict liability and negligence claims—another favorite wrong answer.
Noodle sees the frayed wiring on his toaster, shrugs, and uses it daily until the fire—assumption of risk. Lana never noticed the same fraying—her recovery stands; consumers needn't inspect.
Where the points are
The traps examiners actually set.
- Most tested
- Commercial seller vs. casual seller vs. service provider; the whole chain being strictly liable; design defect's reasonable-alternative-design test; foreseeable misuse still covered.
- Classic traps
- Strict liability against yard-sale Liv (no); the retailer escaping because it “did nothing wrong” (strict = no fault needed); disclaimers defeating injury claims (no); pure economic loss in tort (warranty instead); requiring privity (dead since MacPherson).
Keep going: Torts Attack Sequences Negligence deep dive Vicarious Liability deep dive