Pushing boundaries: public nuisance claims in class actions and mass tort litigation

Canadian businesses saw a significant uptick in public nuisance litigation across various industries in 2024. Traditionally associated with toxic spills and environmental damage, plaintiffs are increasingly asserting the doctrine of public nuisance in product liability claims, class actions, and mass tort litigation. This trend has the potential to affect a diverse array of industries that provide goods and services to consumers, from consumable products and cosmetics to social media.

Unlike traditional product liability causes of action rooted in negligence or misrepresentation, the tort of public nuisance allows plaintiffs to make allegations of harm to broad public interests—such as public health, safety, or the environment—and to avoid the strictures of negligence law. The ongoing attempt by plaintiffs to push public nuisance beyond its recognized boundaries presents a challenging and potentially costly new source of litigation risk for Canadian businesses. If successful, it may expose corporations to liability for events outside their control, including the conduct of others.

What is the tort of public nuisance?

To establish public nuisance at common law, a plaintiff with standing must prove (1) the existence of a public right; and (2) an unreasonable interference with that right¹.

Traditionally, public rights have engaged the use and enjoyment of public property and resources such as land, water, and air². However, creative plaintiffs’ counsel have seized upon abstract and general statements of legal principle to assert broad public interests in “health, safety, morality, comfort, or convenience” that go well beyond a public right of access³. The attempt to expand the scope of public nuisance to novel sets of circumstances is no doubt motivated by a desire to avoid having to prove that a defendant owed or breached a duty or standard of care, as negligence requires.

Without using the phrase “public nuisance”, Québec civil law provides similar remedies under the combined effect of article 1457 of the Civil Code of Québec and article 49 of the Québec Charter of Human Rights and Freedoms. In particular, article 49 of the Québec Charter provides that “[a]ny unlawful interference with any right or freedom recognized by this Charter entitles the victim to obtain the cessation of such interference and compensation for the moral or material prejudice resulting therefrom”. These protected interests may include a broad range of public rights, such as the right to live in a healthful environment under article 46.1 of the Québec Charter.

The risks of public nuisance litigation

Public nuisance can provide an attractive vehicle for class actions and mass tort litigation by providing an arguable right of action based on alleged interference with notionally broad public rights, rather than discrete harms to specific individuals. This has two important practical implications for Canadian businesses.

First, public nuisance claims risk exposing Canadian businesses to legal action by individuals or entities with whom they have no previous relationship. For example, in 2019, the Superior Court of Québec allowed Québec residents to pursue claims against Volkswagen Group Canada based on their public right to a clean environment, even if they had never purchased a Volkswagen automobile. The Superior Court of Québec authorized a class action on behalf of all Québec residents based on allegations that vehicles sold by Volkswagen Group Canada had caused an increase in nitrogen oxide emissions, contrary to the Québec Charter right to live in a healthful environment. Despite acknowledging that this decision would expand the notion of legal standing to sue, the Superior Court of Québec accepted that the public right to a clean environment entitled all Québec residents to pursue claims against Volkswagen Group Canada, even those who had not purchased a Volkswagen vehicle. The Québec Court of Appeal denied leave to appeal, and the Supreme Court of Canada upheld that denial⁴.

Second, public nuisance could help buttress novel product liability claims where claimants seek indirect compensation for the social effects of various products. For example, in 2021, the Ontario Superior Court of Justice rejected a public nuisance claim against Smith & Wesson for the design of a handgun that had been used in a public shooting⁵. Similarly, in 2022, the British Columbia Court of Appeal rejected public nuisance claims against various manufacturers of opioid painkillers alleging that opioid addiction infringed on the public’s rights to health and safety⁶. Although these attempts to reframe private causes of action as public nuisance claims were unsuccessful, plaintiffs’ counsel have not been deterred from continuing to assert public nuisance as a cause of action in class actions and mass tort claims.

The future of public nuisance litigation in Canada

As Canadian trends tend to mirror those in the United States, we expect to see a growing number of environmental, product liability, and healthcare claims framed as interference with both public and private rights, as has been the case south of the border. In many cases, we expect class actions to follow closely behind regulatory investigations or government recoupment actions. Indeed, in November 2024, the Supreme Court of Canada upheld the constitutionality of a 2018 British Columbia statute permitting multiple provinces to join in a single class action against the manufacturers of opioid painkillers, which has provided much of the roadmap for much of the opioid litigation in Canada⁷.

We expect this trend to continue in other health-related areas. In June 2024, the Province of British Columbia commenced a proposed class action on behalf of all provincial and municipal governments in Canada against various manufacturers of products containing polyfluoroalkyl substances (PFAS) in Canada, asserting public nuisance, among other causes of action, on the basis that “PFAS contamination” has allegedly interfered with “the Canadian public’s health, safety, morality, comfort, convenience and right to clean water”⁸. This proceeding was closely followed by proposed class actions in Ontario and British Columbia commenced on behalf of private well owners, similarly asserting public nuisance on the basis of an alleged interference with a public right to clean water⁹. A similar proceeding was also commenced in Québec under the Québec Charter¹⁰.

This framework of alleging that contaminants have interfered with broad public rights to health could apply to a wide variety of industries including cosmetics, health and food products, tobacco alternatives and cannabis products, consumer goods and disposable plastics¹¹.

The public nuisance model is also likely to see increased application in relation to intangible products such as software and social media apps. For example, in 2024, a group of Ontario school boards commenced  actions against various social media companies asserting public nuisance, among other causes of action, on the basis of conduct that allegedly interferes with a public right to education in a “safe and healthy environment”¹². Similar claims could also be targeted at related industries for purported harms to public health.

The importance of rapid response to a changing landscape

Plaintiffs’ attempts to sidestep the well-established guardrails of negligence law by dressing up private rights of action as public nuisance claims is a potentially concerning trend for manufacturers. However, the application of public nuisance law to consumer product and service industries has not yet gained a significant foothold in Canada and has been rejected by one appellate court on the basis that:

[t]he alleged misconduct engaged in this action falls securely within the law of negligence and fraud, including products liability and misrepresentation. Recognizing that the conduct may also amount to public nuisance would distort the boundaries of legal principle, and alter the foundations of compensation for wrongdoing. Public nuisance would risk becoming the emperor of all wrongs. Public nuisance does not depend upon fault so much as the consequences of action. Recognizing public nuisance in situations analogous to these would open the door to all kinds of claims hitherto regulated by the law of negligence¹³.

This and other recent decisions demonstrate that public nuisance remains vulnerable to early defensive challenges. Working quickly to identify potential risks, defendants and their counsel should remain nimble and proactive, considering all options for a rapid response in the early phases of potential litigation.