Strict liability is the part of Torts that breaks the pattern you spent the whole semester learning. Negligence asked whether the defendant behaved unreasonably. Intentional torts asked what was in the defendant's head. Strict liability throws both questions out: the defendant is liable for the harm they cause even if they were careful, even if they had no bad intent, and even if there was nothing more a reasonable person could have done. That is the whole idea, and it is exactly the idea 1Ls forget under exam pressure when they start writing about breach and duty out of habit.

This page gives you the black-letter rule, the elements broken down category by category, the way courts actually apply each element, worked examples, the trap that costs points on the exam, and how strict liability fits with the rest of your Torts course.

What is strict liability?

Strict liability is tort liability imposed without regard to fault. The plaintiff does not prove the defendant breached a duty (negligence) or acted intentionally (intentional torts). Instead, the plaintiff shows that the defendant engaged in a category of activity the law treats as so inherently dangerous, or sells a product so defective, that the defendant must pay for the resulting harm regardless of how much care they used. The policy justification is loss-allocation: the party who profits from an unusually risky activity, and is best positioned to insure against or price in the risk, should bear the cost when that risk materializes.

In first-year Torts, strict liability is almost always taught in three buckets. Learn them as three separate mini-rules, because their elements differ:

1. Abnormally dangerous (ultrahazardous) activities
2. Animals (wild animals and known-dangerous domestic animals)
3. Products liability (defective products)

Category 1: Abnormally dangerous activities — the elements

This is the classic essay category, so know the factors cold. Under the Restatement (Second) of Torts § 520, a court decides whether an activity is abnormally dangerous by weighing six factors:

1. Existence of a high degree of risk of some harm to persons, land, or chattels;
2. Likelihood that the harm that results will be great (severity of harm);
3. Inability to eliminate the risk by the exercise of reasonable care;
4. Extent to which the activity is not a matter of common usage;
5. Inappropriateness of the activity to the place where it is carried on; and
6. Extent to which its value to the community is outweighed by its dangerous attributes.

Note two things. First, whether an activity is abnormally dangerous is a question of law for the judge, not a jury question. Second, no single factor is decisive; the court balances them. But in practice, factor 3 — you cannot make it safe with reasonable care — is the heart of the doctrine. That is the whole reason strict liability exists here: if reasonable care could eliminate the risk, negligence law would do the job, and there would be no need for a no-fault rule.

The Restatement (Third) of Torts § 20 streamlines this into a two-part test: an activity is abnormally dangerous if (1) it creates a foreseeable and highly significant risk of physical harm even when reasonable care is exercised, and (2) it is not one of common usage. If your casebook uses the Third Restatement, lead with that test and mention the § 520 factors as the older, more granular version. If it uses the Second (most 1L casebooks still do), lead with the six factors.

How courts apply the factors

• Blasting / explosives: the paradigm case. Even a careful demolition contractor can send debris or shockwaves onto neighboring property. Reasonable care reduces but cannot eliminate the risk — strict liability applies.
• Storing large quantities of flammable or toxic material: often abnormally dangerous, especially in a populated area (factor 5, wrong place).
• Fumigation with toxic gas, crop dusting, transporting hazardous chemicals: frequently found abnormally dangerous.
• Driving a car, using electricity, ordinary construction: not abnormally dangerous — these are matters of common usage (factor 4) and their risks are managed by ordinary care.

The causation limitation you must not skip

Even inside strict liability, causation matters — and it matters in a specific, testable way. The defendant is strictly liable only for the kind of harm that makes the activity abnormally dangerous in the first place. This is the rule from Rylands v. Fletcher in the English tradition and captured in Restatement (Second) § 519(2): liability is limited to the harm that flows from the risk that made the activity dangerous.

The teaching example: a defendant transports dynamite. If the dynamite explodes and destroys a neighbor's barn, strict liability applies — that is exactly the risk. But if the truck carrying the dynamite negligently runs over a pedestrian, the pedestrian's injury did not flow from the explosive character of dynamite; it flowed from ordinary driving. That plaintiff must sue in negligence, not strict liability. Professors love this distinction because it separates students who memorized "blasting = strict liability" from students who understand the doctrine.

Category 2: Animals

Two separate sub-rules here:

• Wild animals (ferae naturae): An owner or possessor of a wild animal is strictly liable for harm caused by the animal's dangerous propensities characteristic of the species, even if the owner exercised the utmost care to confine it. Lions, tigers, bears, venomous snakes, monkeys — keep one, and you keep the liability.
• Domestic animals: Strict liability applies only if the owner knew or had reason to know of the animal's dangerous propensities — the classic "one free bite" idea (though modern statutes in many states impose strict liability for dog bites without requiring prior knowledge). Absent that knowledge, injuries caused by domestic animals are governed by negligence.

Two nuances that show up on exams. First, like abnormally dangerous activities, animal strict liability is limited to harm from the animal's dangerous propensity — if your neighbor's pet tiger causes a car accident by wandering into the road and the driver swerves, the analysis gets more interesting than "tiger = strict liability." Second, trespassers often cannot recover in strict liability for animal injuries; the owner's duty to a trespasser is limited.

Category 3: Products liability

Strict products liability, drawn from Restatement (Second) of Torts § 402A, holds a commercial seller liable for injuries caused by a product sold in a defective condition unreasonably dangerous to the user, even if the seller exercised all possible care and even though there is no contractual relationship (privity) with the injured plaintiff. The three defect types are:

1. Manufacturing defect — the product departed from its intended design (the one bad unit on the assembly line). Liability is essentially automatic once the defect and causation are shown.
2. Design defect — the entire product line is unreasonably dangerous. Courts use either the consumer-expectations test (more dangerous than an ordinary consumer would expect) or the risk-utility test (a reasonable alternative design would have reduced the risk at acceptable cost). The Restatement (Third) favors risk-utility.
3. Warning/marketing defect — inadequate instructions or failure to warn of a non-obvious danger.

Because products liability is often taught as its own unit, this page treats it as the third strict-liability bucket you must be able to name; if your professor gave it a dedicated week, study it as its own subject. The point for your strict-liability framework: note that fault is irrelevant to whether the product was defective — a manufacturer who tested every unit is still liable for the one defective unit that slips through.

Defenses to strict liability

This is where students lose easy points by importing negligence defenses wholesale. Get the distinctions right:

• Contributory / comparative negligence: Ordinary plaintiff negligence — mere carelessness or failure to discover the danger — is traditionally not a defense to a strict-liability claim. This is a signature difference from a negligence claim. (Many comparative-fault jurisdictions now apportion damages in strict-liability cases, so watch your casebook.)
• Assumption of risk: A plaintiff who knowingly and voluntarily encounters the dangerous condition can have their recovery barred or reduced. This is the defense that works.
• Misuse / abnormal use (products): If the plaintiff used the product in an unforeseeable way, the defect did not cause the harm.

The exam trap

The single most common strict-liability mistake on a 1L exam is writing a negligence analysis by reflex — spending three paragraphs on duty, breach, and the reasonable person when the fact pattern is screaming strict liability. When you see blasting, a captive wild animal, stored explosives, toxic chemicals, or a defective product, your first move is to say the magic words: "Because this is [an abnormally dangerous activity / a wild animal / a defective product], the defendant is liable regardless of fault, and no showing of unreasonable conduct is required."

The second most common mistake is the flip side: assuming that once you're in strict liability, causation and scope vanish. They don't. You still have to run the kind-of-harm limitation (§ 519(2)) — the harm must be the very risk that made the activity abnormally dangerous. A great exam answer names the category, applies the § 520 factors (or the § 20 test), and then separately checks that the harm flowed from the dangerous propensity. That structure is what separates the A from the B+.

Third trap: forgetting that abnormally-dangerous status is a question of law for the judge. If a question asks who decides whether an activity is abnormally dangerous, the answer is the court, not the jury — a clean point most students miss.

How strict liability fits with the rest of Torts

Think of strict liability as one of the three fault regimes you're comparing all semester: intentional torts (fault = intent), negligence (fault = unreasonableness), and strict liability (no fault required). On an issue-spotter, the same facts can support alternative theories — a plaintiff hurt by a defendant's blasting might have both a negligence claim (if the defendant blasted carelessly) and a strict-liability claim (regardless of care). Plead both; the strict-liability theory is easier to win because it removes the breach question.

Related doctrines to keep straight:

• Negligence per se is not strict liability — it still requires a breach (of a statutory standard) and lets the defendant raise negligence defenses. Students conflate them; don't.
• Res ipsa loquitur is also not strict liability — it's a way of inferring negligence from circumstances. Fault is still the issue.
• Vicarious liability (respondeat superior) is a form of liability without personal fault by the employer, and is sometimes grouped conceptually with strict liability, but it's distinct: it depends on an employee's underlying tort.

Master this page and you can do three things on the exam: name the category, run the factors or defect test, and apply the causation limitation — all while resisting the reflex to write a negligence answer. That's the whole doctrine, and it's very learnable once you stop trying to make it about fault.