Strict liability and products liability - Common law strict ...

Learning Outcomes

This article explains common law strict liability for activities and animals, including:

• The doctrinal basis and policy rationale for imposing liability without fault, distinguishing strict liability from negligence, nuisance, and intentional torts.
• The elements for identifying abnormally dangerous activities, with emphasis on factors used by courts and typical MBE fact patterns involving blasting, toxic chemicals, and nuclear or similarly high-risk operations.
• How strict liability applies to wild animals, domestic animals with known dangerous tendencies, and trespassing livestock, as well as the limits on liability for injuries to trespassers and for harms outside the animals’ dangerous propensities.
• The causation and “scope of risk” requirements that confine strict liability to harms arising from the very dangers that justify the doctrine, and how intervening acts and unusual events affect that analysis.
• The principal defenses and limitations in strict liability actions, including assumption of risk, contributory negligence, comparative fault, and statutory modifications, and how they are treated on the MBE.
• Practical strategies for reading MBE questions, spotting when strict liability is triggered, and choosing between strict liability and negligence theories on close exam fact patterns.

MBE Syllabus

For the MBE, you are required to understand strict liability at common law, with a focus on the following syllabus points:

• Recognition of abnormally dangerous activities and when strict liability attaches.
• Strict liability for harm caused by wild animals and domestic animals with known dangerous propensities.
• Distinguishing strict liability from negligence, nuisance, and intentional torts.
• Application of defenses, including assumption of risk, contributory negligence, and comparative fault.
• Understanding the scope of strict liability and the requirement that the harm result from the specific dangerous aspect of the activity or animal.
• Awareness of the relationship between strict liability for activities/animals and strict products liability (addressed separately).

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

1. Which of the following is most likely to give rise to strict liability at common law?
   1. A driver negligently causes a car accident.
   2. A person keeps a tiger as a pet and it escapes, injuring a neighbor.
   3. A store sells spoiled food, causing illness.
   4. A landlord fails to repair a broken stair, resulting in injury.
2. Under common law, strict liability for harm caused by animals applies:
   1. Only to wild animals, never to domestic animals.
   2. Only if the animal owner was negligent.
   3. To wild animals and to domestic animals with known dangerous tendencies.
   4. Only if the animal is used for commercial purposes.
3. Which defense is generally NOT available to a defendant in a strict liability action for abnormally dangerous activities?
   1. Assumption of risk by the plaintiff.
   2. Contributory negligence where the plaintiff failed to appreciate the risk.
   3. The activity was carried out with reasonable care.
   4. The harm was not caused by the dangerous aspect of the activity.

Introduction

Strict liability at common law imposes liability without proof of fault for certain activities and harms. Unlike negligence, strict liability focuses on the nature of the defendant’s activity or animal, not on whether the defendant acted carefully. The main areas where strict liability applies are abnormally dangerous activities and harm caused by animals. Strict products liability (for defective products) is a separate topic and is treated elsewhere.

Understanding when strict liability is imposed, and the limits and defenses to such liability, is essential for MBE success. Many questions will require you to decide quickly whether the facts fit into one of the narrow categories where strict liability is permitted, or instead are governed by ordinary negligence principles.

Key Term: Strict Liability
Liability imposed for harm caused by certain activities or animals, regardless of the defendant’s fault or level of care.

Strict liability does not make the defendant an absolute insurer against all harm. The plaintiff must still prove:

• The defendant engaged in an activity (or kept an animal) that triggers strict liability.
• Factual causation (“but-for” the activity/animal, the harm would not have occurred).
• Proximate causation (the harm is within the scope of risks that make the activity/animal dangerous).
• Actual damages.

Strict Liability: The Principle

Strict liability holds a defendant liable for harm resulting from certain activities, regardless of the level of care exercised. The rationale is that some activities are so hazardous that those who engage in them should bear the risk of harm to others, rather than imposing that risk on innocent members of the public.

Classic MBE-tested sources of strict liability are:

• Abnormally dangerous (ultra-hazardous) activities.
• Animals (wild animals and some domestic animals).
• Defective products (addressed in separate products-liability coverage).

On the exam, if the fact pattern does not involve one of these categories (or an explicit statute imposing strict liability), you should be very cautious about finding strict liability.

Abnormally Dangerous Activities

Strict liability applies to activities that create a significant risk of serious harm even when reasonable care is taken, and which are not common in the community. Classic examples include blasting with explosives, storing large quantities of flammable liquids, or using highly toxic chemicals.

Key Term: Abnormally Dangerous Activity
An activity that creates a foreseeable and highly significant risk of serious harm even when reasonable care is used, and that is not a matter of common usage in the community.

Courts consider several factors in deciding whether an activity is “abnormally dangerous” for strict liability purposes (no single factor is conclusive):

• The degree of risk of harm to others.
• The likelihood that the harm will be great.
• The inability to eliminate the risk by exercising reasonable care.
• The uncommonness of the activity in the community.
• The inappropriateness of the activity to the place where it is carried on.
• The extent to which its value to the community is outweighed by its dangerous attributes.

The usual MBE approach is:

• Blasting, large-scale storage of explosives or highly toxic chemicals, nuclear activities, and some forms of fumigation or crop-dusting are abnormally dangerous.
• Ordinary driving, operating a factory or office building, or storing modest amounts of fuel for normal uses are not abnormally dangerous.

To impose strict liability for an abnormally dangerous activity, the following must be shown:

• The activity creates a high risk of serious harm.
• The risk cannot be eliminated by reasonable care.
• The activity is not commonly carried out in the area.
• The harm results from the dangerous aspect of the activity.

Key Term: Scope of Strict Liability
Strict liability applies only to harm resulting from the type of risk that makes the activity or animal dangerous.

This “scope of risk” requirement is frequently tested. Strict liability applies only when the injury results from the very risk that makes the activity abnormally dangerous.

• If explosives detonate and cause shrapnel injuries, strict liability applies.
• If a truck carrying explosives negligently runs a red light and hits a pedestrian, but the explosives never detonate, the harm results from ordinary driving risks, not from the explosive cargo. No strict liability; negligence governs.

Independent Contractors and Abnormally Dangerous Activities

Even when an abnormally dangerous activity is carried out by an independent contractor (for example, a demolition subcontractor using explosives), the party who hired the contractor often remains strictly liable. The duty to ensure the activity is carried on safely is treated as nondelegable.

Worked Example 1.1

A demolition company uses explosives to demolish a building. Despite all safety precautions, debris flies onto a neighbor’s property, damaging a car. The neighbor sues the company for damages. Is the company strictly liable?

Answer:
Yes. Blasting with explosives is an abnormally dangerous activity. The harm (flying debris) resulted from the dangerous aspect of the activity. Strict liability applies even if the company used reasonable care.

Worked Example 1.2

A trucking company hauls a large quantity of dynamite through a city. The driver is distracted, runs a red light, and collides with another car. The dynamite does not explode, but the other driver is injured in the collision. The injured driver sues on a strict liability theory based on transport of explosives. Will strict liability apply?

Answer:
No. The injury was caused by the truck’s negligent driving, not by the risk that makes transporting explosives abnormally dangerous (explosion). Strict liability covers only harm resulting from the dangerous propensity of the activity. The plaintiff may recover under negligence, but not strict liability.

Animals and Strict Liability

Strict liability also applies to harm caused by animals in two main situations:

Key Term: Wild Animal
An animal that, as a species, is not customarily kept in the service of humankind and that naturally poses a risk of causing substantial personal injury. Owners are strictly liable for harm arising from such an animal’s dangerous propensities.

Key Term: Domestic Animal
An animal that is customarily domesticated and kept in the service of humankind, such as a dog, cat, horse, or cow. Owners are strictly liable only if the particular animal has known dangerous tendencies.

• Wild Animals: Owners are strictly liable for harm caused by wild animals, even if the animal is kept securely and the owner exercised all possible care. The key is that the injury must result from the animal’s dangerous propensities (including the fear it reasonably creates).

• Domestic Animals: Owners are strictly liable only if they knew or should have known of the individual animal’s dangerous propensities (often called the “one-bite rule” in the dog context). Without such knowledge, liability is governed by negligence.

Key Term: Trespassing Animal
A domesticated farm animal (such as cattle, horses, or sheep) that strays onto another’s land. At common law, owners are strictly liable for reasonably foreseeable damage caused by trespassing livestock, but not for trespassing household pets.

Additional points commonly tested:

• Owners are strictly liable for foreseeable harm caused by trespassing livestock (e.g., trampling crops), but usually not for wandering dogs and cats.
• For wild animals kept on land (e.g., a pet wolf or tiger), the possessor is strictly liable for injuries to licensees and invitees on the land. Many jurisdictions do not impose strict liability for injuries to unknown adult trespassers, though ordinary negligence rules still apply.
• Some jurisdictions create an exception and impose strict liability when a landowner keeps a vicious watchdog that injures even a trespasser.

Worked Example 1.3

A homeowner keeps a pet wolf. The wolf escapes from a locked cage and bites a passerby on the sidewalk. The passerby sues the homeowner. Is the homeowner strictly liable?

Answer:
Yes. Keeping a wolf is keeping a wild animal. The owner is strictly liable for harm caused by the animal’s dangerous propensities (biting or causing reasonable fear), regardless of the precautions taken.

Worked Example 1.4

A farmer owns a dog that has never bitten anyone. The dog frequently chases bicycles, and the farmer has been warned several times. One day the dog chases a cyclist into a ditch, causing injury. Is the farmer strictly liable?

Answer:
Yes. Although the dog is a domestic animal, the farmer knew or should have known about this dog’s specific dangerous propensity (chasing cyclists in a way that foreseeably causes injury). That knowledge triggers strict liability for harm arising from that propensity. Even if the dog has never actually bitten anyone, the known tendency is enough.

Worked Example 1.5

A landowner keeps a caged tiger as a tourist attraction on her property. A trespassing adult sneaks onto the property at night to get a close look, leans over the barrier, and is injured when the tiger swipes at him. The trespasser sues on a strict liability theory for wild animals. Is the landowner strictly liable?

Answer:
In many jurisdictions, no. Although owners of wild animals are strictly liable to invitees and licensees, strict liability is often not extended to undiscovered trespassers. The trespasser may still have a negligence claim if the landowner unreasonably maintained dangerous conditions, but strict liability is limited in this context.

Causation and Scope of Liability

Strict liability does not make the defendant an insurer for all harm. The ordinary causation rules still apply:

• Actual Cause (Cause in Fact): The plaintiff must show that but for the defendant’s activity or animal, the harm would not have occurred.
• Proximate Cause (Legal Cause): The harm must result from the type of danger that makes the activity or animal abnormally dangerous.

Key Term: Scope of Strict Liability
Strict liability applies only to harm resulting from the type of risk that makes the activity or animal dangerous; harms outside that risk are governed by negligence or other doctrines.

Abnormally Dangerous Activities

If blasting vibrations crack a neighbor’s building, the harm is within the scope of blasting risks and strict liability applies. If the same blasting operation merely attracts spectators and a spectator later trips over a loose stone far from the site, the harm is not caused by the blasting’s dangerous propensity and strict liability does not apply, though negligence might.

Animals

With animals, strict liability covers:

• Harm caused by the animal’s dangerous propensities (attacks, charging, knocking people over, or reasonably causing panic).
• Harm reasonably resulting from fear of the animal (e.g., a passerby breaks an arm fleeing from a loose poisonous snake).

Strict liability does not cover harms clearly unrelated to the dangerous nature of the activity or animal—for instance, a visitor tripping over a dog’s leash where the dog itself is calm and poses no particular risk.

Worked Example 1.6

A chemical manufacturer stores large quantities of toxic gas in tanks. An earthquake causes one tank to rupture, releasing gas that harms nearby residents. The manufacturer had complied with all safety regulations and used reasonable care. Residents sue on a strict liability theory. Does the intervening earthquake defeat strict liability?

Answer:
No. The very risk that makes storing toxic gas abnormally dangerous is that, if containment fails for any reason, toxic gas will escape and injure others. Even though an earthquake is an intervening natural event, the harm is still within the scope of the risk that makes the activity abnormally dangerous, so strict liability applies.

Defenses to Strict Liability

Strict liability significantly limits defenses based on the defendant’s carefulness. The main defenses (and non-defenses) are:

Key Term: Assumption of Risk
A defense in which the plaintiff knowingly and voluntarily encounters a known, specific risk, thereby consenting to relieve the defendant of liability for resulting harm.

Key Term: Contributory Negligence
The plaintiff’s failure to exercise reasonable care for their own safety, which at common law completely barred recovery in negligence actions.

Key Term: Comparative Fault
A system that reduces the plaintiff’s recovery in proportion to their share of responsibility, even when the defendant is strictly liable.

• Reasonable Care Is Not a Defense: It is no defense that the defendant exercised utmost care. By definition, strict liability applies even when the defendant is non-negligent.

• Assumption of Risk: If the plaintiff knows of the risk and voluntarily chooses to encounter it, recovery may be barred (in contributory negligence jurisdictions) or reduced (in comparative fault jurisdictions).

  • Example: A spectator ignores clearly marked “no-entry” signs and intentionally walks into the blasting zone seconds before detonation, then is injured. This is a strong case for assumption of risk.

• Contributory Negligence:

  • In traditional contributory negligence jurisdictions, ordinary contributory negligence (failure to exercise reasonable care) is generally not a defense to strict liability. A careless plaintiff can still recover.
  • However, if the plaintiff’s conduct amounts to knowingly encountering a known risk, many courts treat this as assumption of risk and bar recovery.

• Comparative Fault: Most modern jurisdictions apply comparative fault principles even in strict liability cases. The defendant’s liability is strict, but the plaintiff’s damages are reduced in proportion to their share of fault.

  • Example: In a blasting case, if the plaintiff disregards repeated warnings and stands closer than permitted to the blast, damages may be reduced under comparative fault.

• “Not the Dangerous Propensity” / “Not the Dangerous Aspect”: If the harm did not result from the dangerous aspect of the activity or animal, strict liability does not apply at all. The case must be analyzed under negligence or another theory.

  • Example: A visitor trips on a decorative rock in a zoo while walking toward the lion enclosure. Any claim must be based on premises liability, not strict liability for wild animals, because the injury does not arise from the lions’ dangerous propensities.

• Statutory Modifications: Some statutes (for example, modern “dog-bite” laws) modify common law rules, sometimes imposing strict liability without requiring proof of prior dangerousness. On the MBE, unless the statute is quoted, assume traditional common law rules apply.

Revision Tip

Remember: Strict liability is limited. Ask three questions—(1) Is this an abnormally dangerous activity, a wild animal, or a domestic animal with known dangerous propensities? (2) Did the harm come from the dangerous aspect of that activity or animal? (3) Did the plaintiff knowingly assume the risk? If any answer is “no,” strict liability may not apply or may be reduced.

Worked Example 1.7

A quarry company posts prominent warning signs and erects barriers around its blasting site. A local resident, curious to “get a closer look,” climbs over the barrier during a scheduled blast despite seeing the warning signs, and is injured by flying debris. She sues on a strict liability theory. The jurisdiction follows pure comparative fault. How will her conduct affect recovery?

Answer:
The quarry is strictly liable because blasting is abnormally dangerous and the injury arose from the blasting’s dangerous propensity (flying debris). However, the plaintiff’s deliberate decision to ignore warnings and bypass barriers will likely be treated as significant comparative fault, reducing her damages in proportion to her share of responsibility.

Worked Example 1.8

A cattle rancher’s cows break through a poorly maintained fence and trample a neighbor’s vegetable garden. The neighbor sues. The rancher argues that he had no reason to know the cows would escape and that he generally keeps his fences in good repair. Is he strictly liable?

Answer:
Yes. At common law, owners are strictly liable for reasonably foreseeable damage caused by trespassing livestock. Because this harm is the natural result of the animals’ trespass, the owner’s level of care does not matter for strict-liability purposes, though it might affect any negligence analysis.

Exam Warning

In strict liability questions, always check that the harm resulted from the dangerous aspect of the activity or animal. If the harm is unrelated (e.g., a passerby trips over a blasting company’s sign or a visitor slips on spilled soda near a tiger cage), strict liability does not apply. Analyze those claims under negligence or premises liability instead.

Revision Tip

Strict liability does not apply to all dangerous activities—only those that are abnormally dangerous and not common in the area, or to the limited animal situations described. If you do not see blasting, toxic chemicals, nuclear hazards, wild animals, or domestic animals with known dangerous tendencies, think negligence before strict liability.

Key Point Checklist

This article has covered the following key knowledge points:

• Strict liability at common law imposes liability without fault for certain activities and animals, but the plaintiff must still prove causation and damages.
• Abnormally dangerous activities (e.g., blasting, large-scale storage of explosives or toxic chemicals) attract strict liability if harm results from the dangerous aspect of the activity.
• Courts assess abnormally dangerous activities by considering risk, seriousness of harm, inability to eliminate the risk by due care, uncommonness in the community, appropriateness of the location, and the activity’s value to the community.
• Owners of wild animals are strictly liable for harm caused by the animals’ dangerous propensities to licensees and invitees, and often for foreseeable fear-based injuries; liability to trespassers is more limited.
• Owners of domestic animals are strictly liable only if the particular animal has known dangerous tendencies; otherwise, negligence governs.
• Owners of trespassing livestock are strictly liable for reasonably foreseeable property damage; trespassing household pets generally do not trigger strict liability.
• Strict liability is limited by the “scope of risk” requirement: the harm must stem from the very risk that makes the activity or animal dangerous.
• Reasonable care is not a defense to strict liability, but assumption of risk and comparative fault can reduce or bar recovery.
• Ordinary contributory negligence is usually not a defense to strict liability unless it amounts to knowing assumption of risk.
• Strict liability for activities and animals is conceptually distinct from strict products liability, which has its own elements and defenses.

Key Terms and Concepts

• Strict Liability
• Abnormally Dangerous Activity
• Wild Animal
• Domestic Animal
• Trespassing Animal
• Scope of Strict Liability
• Assumption of Risk
• Contributory Negligence
• Comparative Fault