Negligence

Understanding Negligence Law in Ontario

Negligence is the cornerstone of modern tort law in Canada. It governs virtually every activity imaginable—from how motorists drive, to how professionals practice their crafts, to how property owners maintain their premises. Understanding negligence is essential whether you are seeking compensation for injuries suffered or defending against claims of wrongful conduct.

The scope of negligence law is remarkably broad. Courts have held that negligence standards apply to skiing accidents, racing car drivers, airline operations, jailers supervising inmates, nurses rushing to attend patients, and countless other scenarios. There is virtually no activity—new or old, rare or commonplace, dangerous or safe—that can escape review by negligence standards.

The Elements of Negligence

To establish a negligence claim in Ontario, a plaintiff must prove three essential elements:

1. Duty of Care: The defendant owed a legal duty to take reasonable care to avoid causing harm to the plaintiff. This is fundamentally a question of law.
2. Breach of the Standard of Care: The defendant failed to meet the required standard of care. While defining the legal standard is a question of law, determining whether the defendant actually met that standard is a question of fact.
3. Causation and Damages: The defendant's breach caused actual harm or loss to the plaintiff.

This guide focuses on the second element—the standard of care and its breach—which is where most negligence disputes are won or lost. A superb example of the correct judicial approach to assessing standard of care is Hill v. Hamilton-Wentworth Regional Police Services Board.

The Standard of Care: What is "Reasonable"?

The standard of care in negligence law is an objective standard, not a subjective one. The basic standard is that expected from a fictional "reasonable person"—someone who would never take an unreasonable risk.

The Objective Reasonable Person

Courts have described the reasonable person as:

A mythical creature of the law whose conduct is the standard by which the Courts measure the conduct of all other persons and find it to be proper or improper in particular circumstances as they may exist from time to time. He is not an extraordinary or unusual creature; he is not superhuman; he is not required to display the highest skill of which anyone is capable; he is not a genius who can perform uncommon feats, nor is he possessed of unusual powers of foresight. He is a person of normal intelligence who makes prudence a guide to his conduct. He does nothing that a prudent man would not do and does not omit to do anything that a prudent man would do.

Although the courts pursue a common objective standard, subjective elements occasionally intrude. The standard varies depending on the class of defendant involved—children are judged differently than adults, professionals differently than laypeople, and those with physical disabilities are held to modified standards accounting for their limitations.

Fault Without Moral Blame

The words "fault" and "blame" are employed in negligence law, but without the moral opprobrium attached to these terms in criminal law. Negligence is about unreasonableness, not moral culpability. These terms have acquired special meanings that vary according to the context and the class of defendant involved.

This distinction is crucial: being found negligent does not mean you are a bad person or acted with evil intent. It simply means your conduct fell below what the law considers reasonable in the circumstances.

Assessing Unreasonable Risk: The Four-Factor Test

Determining whether conduct is negligent requires assessing whether the defendant took an "unreasonable risk." Courts balance four key factors in making this determination:

1. The probability that harm will occur
2. The magnitude of potential loss if harm occurs
3. The social utility of the defendant's conduct
4. The cost of taking precautions

Famous American jurist Judge Learned Hand articulated this balancing test mathematically: liability exists when the burden of adequate precautions (B) is less than the probability of harm (P) multiplied by the magnitude of loss (L). In other words: if B < P × L, the defendant is liable.

While Canadian courts do not apply this formula rigidly, they do engage in similar balancing exercises. Let us examine each factor in detail.

Factor 1: Probability of Harm

If there is only a slight risk that an accident will occur, courts may hold that running such a risk is not unreasonable. As the law recognizes, "people must guard against reasonable probabilities, but they are not bound to guard against fantastic possibilities." However, "probability" does not mean the accident must be more likely than not—there need only be a real or substantial risk of harm. One chance in 100 or even 1,000 may suffice.

Canadian Applications of the Probability Factor

Two contrasting Canadian cases illustrate these principles:

• Shilson v. Northern Ontario Light and Power Co.: A 12-year-old boy was injured by an electric wire while crossing a ravine on a 12-inch pipe. The court held it was so improbable that "even a venturesome and mischievous boy" would attempt to cross a ravine 17-19 feet deep and 300 feet wide on a narrow pipe that the defendant owed no duty to take precautions.
• Gloster v. Toronto Electric Light Co.: An eight-and-a-half-year-old child touched an uninsulated wire 14-20 inches from a bridge used by many people daily. Recovery was permitted because the probability of someone touching this wire was significant enough to call for safety measures.

Weather and Extraordinary Conditions

Steps must be taken to prevent damage from normal weather vicissitudes, but not from abnormally severe conditions that rarely occur. Courts have declined to impose liability for loss caused by:

• Unprecedented frosts
• "Extraordinary falls of rain" or rains of "exceptional character"
• "Cyclones, tornados, hurricanes" of "unique, severe and exceptional kind"
• Fires ignited in ways no one had experienced before, even in dry conditions

However, liability has been imposed for structures blown down by winds characterized as "violent, but not of unusual violence." The distinction lies in whether the weather event was within the realm of normal expectation or truly extraordinary.

Sensitivity and Special Vulnerabilities

Extraordinarily sensitive individuals are generally denied special protection because they are seldom encountered. In Elverson v. Doctors Hospital, a hospital was relieved of liability when a plaintiff aggravated a pre-existing back condition while helping a nurse elevate a patient's bed. The court held this was a "common, everyday occurrence, completely devoid of any inherent danger" and that "the particular susceptibility of the plaintiff was beyond any range of normal expectancy or of reasonable foresight."

Similarly, in Munshaw Colour Service Ltd. v. Vancouver (City), when sediment in city water damaged a film company's specialized filtering equipment, the court held that municipalities cannot be expected to consider "consumers of peculiar sensitivity." Those with particular requirements above the ordinary must deal with them as part of their operation.

Factor 2: Magnitude of Potential Loss

When the potential loss is great, even creating a slight risk may give rise to liability. As Professor Fleming wrote: "Not only the greater risk of injury, but also the risk of greater injury is a relative and relevant factor."

Even if lightning is highly unlikely to strike at a given place and time, one must take precautions against this "extreme hazard" because the precautions must be "commensurate with the danger." If the threatened harm in Bolton v. Stone had been "a bullet in the heart or a nuclear explosion, rather than just a bump on the head," the defendant might have been liable despite the low probability.

Dean Prosser summarized the principle: "As the gravity of the possible harm increases, the apparent likelihood of its occurrence need be correspondingly less to generate a duty of precaution."

Factor 3: Social Utility of the Conduct

Even with substantial risk and potentially severe damage, defendants may be excused if their activities have high social utility. Where the objectives served are laudable enough, risks may be taken.

Police Pursuits and Public Safety Activities

The leading case is Priestman v. Colangelo and Smythson, involving a 17-year-old car thief fleeing from police along Toronto streets. When the youth refused to stop after warning shots, an officer aimed at a tire but accidentally shot the driver in the neck due to a bump in the road. The car went out of control and fatally injured two young women waiting for a bus.

The Supreme Court of Canada, in a 3-2 decision, dismissed the families' claims. The majority held that the hazard created was not too great given "the social value of capturing a criminal whose actions constitute a menace to other members of the public." The police could take certain reasonable risks in apprehending fleeing criminals, though they could not do anything that came to mind.

However, it is likely the dissenting views would prevail today. Society has come to recognize much safer methods of arresting car thieves than high-speed chases or gunfire.

Other High-Utility Activities

Courts have recognized that certain activities, while risky, serve such important social purposes that they warrant acceptance of some danger:

• Emergency medical procedures where speed is essential
• Fire rescue operations
• Essential infrastructure work during emergencies
• Military operations and training

The key is whether the social benefit justifies the risk created. Activities must still be conducted with reasonable care given the circumstances, but the threshold for what constitutes "reasonable" adjusts based on social utility.

Factor 4: Cost of Precautions

The burden or cost of taking adequate precautions is a relevant factor in determining negligence. If precautions would be disproportionately expensive or impractical compared to the risk, courts may excuse their absence.

However, this factor has limits. Where an activity creates substantial risks, it should either be conducted with proper precautions or not conducted at all. As Lord Reid noted in Bolton v. Stone, "if cricket cannot be played on a ground creating a substantial risk, then it should not be played there at all." The activity's social utility does not justify continuing to engage in it if the risks cannot be adequately managed.

This principle extends across industries:

• Construction companies cannot plead poverty as an excuse for failing to provide basic safety equipment
• Manufacturers cannot avoid recalls of dangerous products based on cost considerations alone
• Property owners cannot neglect essential maintenance simply because repairs are expensive

Courts will consider whether the precautions demanded are reasonable given the defendant's circumstances, but cost cannot trump clear and substantial dangers.

The Reasonable Person Standard

The concept of the "reasonable person" is central to negligence law. This fictional legal character serves as the benchmark against which all conduct is measured. Understanding this standard—and how it is modified in different contexts—is essential to both pursuing and defending negligence claims.

Characteristics of the Reasonable Person

Intelligence and Knowledge

The reasonable person is assumed to possess normal intelligence and the knowledge that an ordinary person would have in the circumstances. This includes:

• General knowledge and common sense that adults typically possess
• Awareness of obvious dangers and common risks
• Knowledge of basic physical laws and cause-and-effect relationships
• Information that would be readily apparent through ordinary observation

However, the reasonable person is not expected to have specialized knowledge unless the defendant actually possesses such knowledge or the circumstances require it.

The Duty to Expand Knowledge by Consulting

While the reasonable person is not expected to possess specialized knowledge, there are circumstances where a reasonable person would recognize their limitations and seek expert advice. A property owner undertaking complex structural work, for instance, might be expected to consult an engineer. A business owner implementing new safety procedures might need to consult safety professionals.

The duty to consult arises when:

• The risks are significant and apparent
• The activity is beyond ordinary competence
• Expert knowledge is readily available and accessible
• A reasonable person would recognize the need for specialized input

Physical Disabilities

The law makes accommodations for physical disabilities. A person with impaired vision, hearing, or mobility is held to the standard of a reasonable person with similar disabilities, not to the standard of a fully able-bodied person.

This modification recognizes that it would be unfair and impractical to hold people to standards they physically cannot meet. However, this accommodation has limits:

• People with disabilities must still take reasonable precautions given their limitations
• They may have a duty to avoid activities their disability makes unreasonably dangerous
• They cannot claim disability as an excuse if they chose to engage in activities beyond their capabilities

Superior Knowledge and Skills

While the basic standard is that of a reasonable person, those who possess superior knowledge, skills, or training are held to a higher standard reflecting those advantages. A surgeon is held to the standard of a reasonable surgeon, not simply a reasonable person. An experienced driver is held to a higher standard than a newly licensed one.

This principle ensures that defendants cannot avoid liability by claiming ignorance of matters they actually know or by failing to use skills they actually possess.

Control of Children

Parents and guardians have a duty to exercise reasonable care in supervising children under their control. The standard is not one of perfect supervision—children will inevitably find ways to get into mischief—but rather reasonable oversight given:

• The child's age and maturity
• The child's known propensities and character
• The nature of the setting or environment
• The foreseeable risks present

The duty of supervision exists not only to protect the children themselves but also to protect third parties from harm the children might cause.

Modifications to the Reasonable Person Standard

While the reasonable person standard is generally objective, the law recognizes that certain classes of defendants require modified standards to account for their unique circumstances. These modifications primarily apply to children, those with mental illness, and professionals.

Youth and the Standard of Care

Children of Tender Age

Very young children—generally those under seven years old—are presumed incapable of negligence. This reflects the reality that children at this developmental stage cannot be expected to appreciate risks or make mature judgments about their conduct.

This presumption is rebuttable in some jurisdictions, meaning that in extraordinary circumstances, evidence might establish that even a very young child could understand the risks involved in particular conduct. However, such cases are rare.

Children Beyond Tender Age

For children old enough to potentially be held negligent but not yet adults, courts apply a modified standard: that of a reasonable child of similar age, intelligence, and experience.

Key principles include:

• Subjective factors matter: Unlike the purely objective adult standard, the child standard considers the individual child's actual age, intelligence, and experience
• Incrementally increasing expectations: The older the child, the closer the standard approaches that of an adult
• Context-specific assessment: What is expected of a 10-year-old riding a bicycle differs from what is expected of that same child operating a boat

Courts recognize that children:

• May not appreciate risks that adults readily recognize
• Have less developed judgment and impulse control
• Are more prone to distraction and inattention
• May overestimate their own abilities
• Are less likely to consider consequences before acting

The Adult Activity Exception

An important exception exists when children engage in "adult activities." When a minor operates motor vehicles, boats, or other potentially dangerous equipment typically used by adults, courts generally hold the child to an adult standard of care.

The rationale is straightforward: other users of the roadways or waterways have no way of knowing whether the driver or operator is a child or an adult, and they are entitled to expect adult levels of competence from those operating these vehicles. To hold child operators to a lesser standard would create unacceptable risks for others.

This exception typically applies to:

• Operating automobiles, trucks, and motorcycles
• Operating boats and watercraft
• Operating farm equipment and heavy machinery
• Handling firearms
• Other activities carrying serious risks where age-based standards would endanger others

Mental Illness and Cognitive Impairment

The law's treatment of mental illness in negligence claims is more nuanced and contested than its treatment of children. The general rule—though subject to significant criticism and some exceptions—is that mental illness or cognitive impairment does not excuse conduct that would otherwise be negligent.

The Traditional Rule

Courts have traditionally held that defendants with mental illness are judged by the same reasonable person standard as everyone else. The rationale includes:

• Difficulty of assessment: Mental conditions vary widely in nature and severity, making it difficult to determine appropriate modified standards
• Risk of fabrication: Concerns that defendants might fake or exaggerate mental illness to avoid liability
• Victim protection: Injured parties should not bear losses simply because the person who caused them had a mental illness
• Incentive structure: Caregivers and family members may be more diligent in supervision if liability is not excused by mental illness

Criticisms and Exceptions

This traditional rule has been heavily criticized as unduly harsh and inconsistent with accommodations made for children and physical disabilities. Some argue it fails to recognize that mental illness can be as limiting as physical disability.

Courts have carved out limited exceptions, particularly where:

• The mental condition arose suddenly and without warning
• The defendant had no prior knowledge of the condition
• The defendant could not have reasonably foreseen the episode
• The defendant took reasonable precautions given their knowledge of the condition

Professional Negligence

Professionals—including lawyers, doctors, accountants, engineers, architects, and others—are held to the standard of a reasonably competent practitioner in their field, not merely to the standard of a reasonable layperson.

As courts have explained:

The degree of skill consistent with the function discharged, that is, consistent with the measure of skill displayed by others reasonably competent in that profession touching matters of like kind. Perfection is not expected; the world of work, not the ideal of the debating area, is the standard.

Key Principles of Professional Negligence

1. Reasonable Competence, Not Perfection

Professionals are not guarantors of results. They are required to exercise the skill and care that would be exercised by a reasonably competent professional in similar circumstances. Mere errors in judgment or unsuccessful outcomes do not constitute negligence if the professional acted competently.

2. Specialist Standards

Specialists are held to the standard of reasonable specialists in their specific field. A cardiologist is held to the standard of a reasonable cardiologist, not merely that of a general practitioner. A patent lawyer is held to the standard of a reasonable patent lawyer, not merely that of a general practitioner lawyer.

3. Keeping Reasonably Current

Professionals must keep reasonably abreast of developments in their fields. They need not know every new study or technique, but they must maintain reasonable competence through continuing education and awareness of significant developments.

4. Honest Errors of Judgment

Where professional practice involves the exercise of judgment, professionals are not liable for honest errors of judgment, provided they acted with reasonable care. Multiple approaches may be acceptable, and choosing one approach over another does not constitute negligence simply because a different approach might have worked better.

5. Informed Consent and Communication

Many professional negligence cases involve failures of communication. Doctors must obtain informed consent. Lawyers must properly explain risks and options to clients. Accountants must ensure clients understand their advice. The duty of care encompasses both technical competence and adequate communication.

Establishing Professional Negligence

Proving professional negligence typically requires expert testimony. Because the standard is that of a reasonable professional, not a layperson, plaintiffs must usually present evidence from other professionals explaining:

• What a reasonably competent professional would have done in the circumstances
• How the defendant's conduct fell below that standard
• How that deviation caused the plaintiff's injuries

Exceptions exist where the negligence is so obvious that laypeople can readily understand it—for instance, operating on the wrong body part or missing an obvious statutory deadline.

Custom and Industry Standards

The relationship between custom and negligence is complex. Prevailing industry practices are relevant evidence in determining the standard of care, but they are not conclusive. Courts maintain the authority to find conduct negligent even if it conforms to industry custom, and conversely, to excuse conduct that deviates from custom.

Compliance with Custom as Evidence of Reasonable Care

Evidence that a defendant complied with industry custom or accepted practices is admissible and often persuasive. If most people engaged in similar activities follow certain procedures, this suggests those procedures represent reasonable care.

Courts will consider:

• How widespread the practice is in the industry
• How long the practice has been followed
• Whether the practice is codified in industry standards or regulations
• Whether the practice is followed by reputable practitioners
• Whether there is consensus in the industry about appropriate methods

However, custom is not a complete defense. The question remains whether the custom itself represents reasonable care.

Deviation from Custom

Evidence that a defendant deviated from industry custom is likewise admissible and relevant. If everyone else in the industry uses safety equipment that the defendant omitted, this is probative of negligence.

However, mere deviation from custom does not automatically establish negligence. The deviation must be unreasonable. Courts recognize that:

• Progress requires innovation and deviation from established practices
• Custom may lag behind available safety improvements
• Individual circumstances may justify different approaches
• Custom may be based on cost-cutting rather than safety considerations

When Custom Itself Is Negligent

Perhaps most importantly, courts have held that compliance with custom does not necessarily demonstrate reasonable care. Industry-wide practices can themselves be negligent.

Courts will scrutinize custom when:

• The custom creates obvious and substantial risks
• Better safety measures are available and feasible
• The custom appears driven by cost savings rather than reasonable safety considerations
• The custom has not kept pace with technological or safety advances
• The custom serves the industry's interests at the expense of public safety

This principle prevents industries from insulating themselves from liability by collectively adopting unsafe but profitable practices. As Justice Learned Hand famously stated, "a whole calling may have unduly lagged in the adoption of new and available devices." Courts retain the power to declare that an entire industry's customary practices fall below reasonable standards of care.

Proving Custom

Establishing what constitutes industry custom requires evidence. Parties typically present:

• Expert testimony: Practitioners in the field testify about accepted practices
• Industry standards: Written standards, guidelines, or codes of practice
• Statistical evidence: Surveys or studies showing what percentage of practitioners follow certain practices
• Historical evidence: Documentation of how practices have evolved
• Regulatory materials: Government or professional body publications

The burden of proving custom—and proving compliance with or deviation from it—rests with the party relying on such evidence.

Statutory Violations and the Standard of Care

The relationship between statutory violations and negligence liability has been a source of confusion and controversy. When a defendant violates a safety statute or regulation, does this automatically establish negligence? The answer in Canada was definitively clarified by the Supreme Court in Canada v. Saskatchewan Wheat Pool.

The Law Before Saskatchewan Wheat Pool

Prior to 1983, Canadian courts applied an inconsistent and problematic approach to statutory violations. Courts claimed to search for "legislative intent" to determine whether a statute's violation would give rise to civil liability. The problems with this approach were manifold:

• Most statutes say nothing about civil liability—legislators simply prohibit conduct and specify penalties
• True legislative intent was rarely apparent in the statutory text
• The imposition of civil liability became "capricious" and "impossible to predict on any rational basis"
• Lord Denning described this area of law as a "guesswork puzzle" where one "might as well toss a coin to decide it"

Courts did establish some limiting principles—they would not consider a statutory breach relevant unless:

• The legislative provision was actually violated
• Some loss was caused to the plaintiff by the violation
• The accident was of a kind the statute aimed to prevent
• The plaintiff was within the class of persons the statute protected

However, these were principles of exclusion, not inclusion. They told courts when not to rely on penal violations, but provided no guidance on when they should rely on them.

The Saskatchewan Wheat Pool Decision

In a "learned, bold and unanimous decision," the Supreme Court of Canada fundamentally reformed Canadian law in Canada v. Saskatchewan Wheat Pool.

The Facts

The plaintiff incurred expenses after receiving wheat infested with rusty grain beetle larvae from the defendant. The defendant violated the Canada Grain Act, which forbade discharging infested grain from elevators. However, according to all the evidence, the defendant's conduct was completely free of any negligence—the infestation was essentially unavoidable despite reasonable care.

The Court's Holdings

Justice Dickson (as he then was) made several decisive rulings:

1. Legislative Intent Theory Rejected

The Court abandoned the "fictitious hunt for legislative intent," calling it "capricious and arbitrary" and a "bare-faced fiction at odds with accepted canons of statutory interpretation." Instead, the Court recognized that whether to rely on statutory violations in tort cases is "a question to be decided by the court" based on "considerations of policy and convenience."

2. Statutory Breach Located Within Negligence Law

The Court decisively rejected the notion of a separate "tort of breach of statutory duty." Instead, statutory violations were brought squarely within negligence law. Civil liability for statutory breach is "a creature of the court," not of the legislature.

3. Breach as Evidence, Not Proof

The Court adopted the principle that "proof of statutory breach, causative of damages, may be evidence of negligence." This means:

• Judges and juries may consider statutory violations in their deliberations
• They are not controlled by this evidence—they can find negligence without a statutory violation, or find no negligence despite a violation
• Defendants who violate statutes are not required to prove they exercised reasonable care (reversing earlier authority)
• If defendants remain silent, they may still be exonerated, though silence might be risky

This approach rejects both the American view that statutory violations constitute "negligence per se" (automatic strict liability) and the former Canadian view that violations provide "prima facie evidence" of negligence (shifting burden of proof).

The Court's Reasoning

Justice Dickson offered several reasons for affording less weight to statutory violations:

• Intellectual honesty: It avoids fictitious searches for non-existent legislative intent
• Flexibility: It prevents inflexible application of criminal standards to civil cases
• Legislative activity: Modern legislatures actively create compensation schemes when they want them—silence suggests no such intent
• Alternative compensation: Non-tort compensation schemes have reduced the need for tort recovery
• Fault principles: Tort law increasingly emphasizes fault; there is "little defensible policy for holding a defendant who breached a statutory duty unwittingly to be negligent and obligated to pay even though not at fault"
• Proportionality: "Inconsequential violations should not subject the violator to any civil liability" but should be left to criminal courts
• Natural justice: The trend is to "ameliorate the rigors of absolute rules and absolute duty as contrary to natural justice"

Industrial Safety Legislation Exception

The Court recognized that "industrial legislation historically has enjoyed special consideration," sometimes leading to absolute liability regardless of fault. This exception was permitted to continue, though its practical utility is limited in Canada given extensive workers' compensation legislation.

Application in Practice

Under the Saskatchewan Wheat Pool approach, statutory violations function as one piece of evidence among many. Courts will consider:

• Whether the statute represents a legislative judgment about reasonable care in specific circumstances
• Whether the statutory standard is appropriate to adopt as the civil standard
• Whether the violation was inadvertent or egregious
• Whether the violation actually contributed to the harm
• All other circumstances bearing on whether the conduct was reasonable

The result is a more flexible, honest, and just approach that empowers judges and juries to make reasonable assessments rather than being bound by rigid rules disconnected from actual fault.