Proposition 65 in Canada is a question with a short answer: the law is Californian, but it reaches Canadian businesses whose products end up in California consumers’ hands. Officially the Safe Drinking Water and Toxic Enforcement Act of 1986, Proposition 65 requires warnings before exposing anyone in California to any of roughly 900 chemicals the state has identified as causing cancer or reproductive harm.1Office of Environmental Health Hazard Assessment. About Proposition 65 It regulates the location of the exposure, not the origin of the product, so a Canadian manufacturer shipping into California carries the same obligations as a company headquartered in Los Angeles. Compliance with Canadian chemical rules does not satisfy it.
Which Canadian Businesses Are Covered
The statute prohibits any “person in the course of doing business” from knowingly exposing an individual in California to a listed chemical without first providing a clear and reasonable warning.2California Legislative Information. California Health and Safety Code HSC 25249.6 That language is broad enough to cover a Canadian manufacturer, distributor, or online retailer whose goods reach California.
The one size-based carve-out matters for small Canadian exporters: businesses with fewer than 10 employees are exempt from the warning requirement and the discharge ban.3Office of Environmental Health Hazard Assessment. Businesses and Proposition 65 The count is total employees worldwide, not just staff in California or the United States.4California Legislative Information. California Health and Safety Code HSC 25249.11 A ten-person Canadian company that sells into California is covered. Health Canada plays no role in enforcement, and the Canadian framework and California’s are entirely separate regimes.
When a Warning Is Not Required
Proposition 65 regulates exposure, not mere presence. If anticipated consumer exposure falls below a designated safe harbor threshold, no warning is needed.5Office of Environmental Health Hazard Assessment. Proposition 65 No Significant Risk Levels (NSRLs) and Maximum Allowable Dose Levels (MADLs) The thresholds come in two forms:
- No Significant Risk Levels (NSRLs) apply to chemicals listed as carcinogens. An NSRL is calculated to produce no more than one excess cancer case per 100,000 people over a 70-year lifetime.
- Maximum Allowable Dose Levels (MADLs) apply to reproductive toxicants. A MADL is the level at which no observable reproductive effect would occur even at 1,000 times the actual exposure.
The point that trips up Canadian exporters: concentration in a product is not the same as consumer exposure. Exposure depends on how much a person actually ingests, inhales, or absorbs during normal use. A product may contain a listed chemical at a measurable level yet still fall below the NSRL or MADL when used as intended. OEHHA publishes safe harbor levels for many listed chemicals but not all of them; where none exists, the business bears the burden of proving the exposure poses no significant risk.6Office of the Attorney General. Proposition 65 Frequently Asked Questions
Beyond the safe harbor route, listed chemicals occurring naturally in food are exempt if the business shows levels have been reduced to the lowest currently feasible amount.6Office of the Attorney General. Proposition 65 Frequently Asked Questions Government agencies and public water systems are also exempt, which is rarely relevant to Canadian exporters.
What a Compliant Warning Looks Like
When exposure exceeds safe harbor levels and no exemption applies, the business must provide a “clear and reasonable warning” before the exposure occurs. The regulations spell out a safe harbor format that, if followed exactly, insulates the business from claims that the warning was inadequate.
A compliant consumer product warning displays a yellow equilateral triangle containing a black exclamation point, with a bold black outline, placed to the left of the warning text. Black and white is acceptable where the label itself is not printed in color. The word “WARNING” appears in bold capitals, followed by language that names at least one listed chemical and states whether it is known to cause cancer, reproductive harm, or both. The warning must direct consumers to www.P65Warnings.ca.gov.7Legal Information Institute. California Code of Regulations Title 27 25603 – Consumer Product Exposure Warnings
The 2025 Short-Form Change
Businesses with limited label space have long used a shorter version of the warning. Regulations amended effective January 1, 2025 now require even short-form warnings to name at least one chemical. Companies still using the older short-form without a chemical name have a three-year transition window, so the previous format remains a valid safe harbor through roughly the end of 2027.8Office of Environmental Health Hazard Assessment. Proposition 65 Clear and Reasonable Warnings – Safe Harbor Methods and Content If you are designing new packaging now, adopt the updated format rather than relying on the transition period.
Online and Catalog Sales
A Canadian company selling directly to California consumers through its own website faces the same obligation as a storefront. The warning must appear on the product display page, through a clearly labeled hyperlink on that page, or be prominently shown to the consumer before purchase is completed. Burying it in terms-of-service pages or a post-purchase confirmation email does not qualify.
Who in the Supply Chain Is Responsible
Proposition 65 does not pin the warning obligation solely on the manufacturer. A manufacturer, importer, or distributor can satisfy its duty either by placing the warning on the product itself or by giving written notice to the downstream retailer or distributor that the product requires one. Parties in the chain can also contract to allocate who bears legal responsibility, as long as the consumer actually receives a compliant warning.
This is where supply chain structure drives the risk. A Canadian manufacturer that exports through a U.S. distributor can pass the labeling obligation downstream by giving proper written notice, and should capture that allocation in writing. A Canadian company selling directly to California consumers has nobody downstream, and the obligation stays with it.
Enforcement and the 60-Day Notice
Proposition 65 enforcement is unusually aggressive, and it catches foreign companies off guard. The California Attorney General, any district attorney, and city attorneys in cities with populations over 750,000 may enforce the law. So may any individual acting in the public interest, and that private right of action drives most of the activity.9California Legislative Information. California Health and Safety Code 25249.7 Total payments from enforcement actions exceeded $100 million in 2024.
Penalties can reach $2,500 per day for each violation, and courts routinely add attorney fees and injunctive relief, which can include orders to reformulate products.9California Legislative Information. California Health and Safety Code 25249.7 When setting penalties, the court weighs the nature and severity of the violation, the economic impact on the business, good-faith compliance efforts, and the deterrent effect on the broader regulated community.
Before suing, a private enforcer must serve a 60-day notice of violation on the business, the Attorney General, and the relevant local prosecutor, with a certificate of merit stating the enforcer has consulted a qualified expert and reviewed supporting data.9California Legislative Information. California Health and Safety Code 25249.7 The 60-day window lets a government prosecutor take over. If none does, the private enforcer can proceed.
For a Canadian business, this notice is the decision point. Options include negotiating a settlement (typically a monetary payment plus a commitment to add compliant warnings going forward), commissioning lab testing to show that actual exposure falls below the relevant threshold, or asserting another exemption. Ignoring the notice is the worst option. Defense costs climb quickly once suit is filed, and being outside the United States does not prevent a default judgment.
One procedural wrinkle to plan for: once a plaintiff shows a listed chemical is present in the product, even at very low levels, the burden shifts to the defendant to prove the exposure does not require a warning. You cannot wait for the plaintiff to prove harm. You have to produce the exposure analysis yourself.
Why Canadian Compliance Isn’t Enough
Canada regulates hazardous chemicals through a different framework. The Workplace Hazardous Materials Information System (WHMIS) covers chemicals used in workplaces, but its scope is occupational, not consumer-facing. The Canada Consumer Chemicals and Containers Regulations require disclosure of hazardous ingredients at concentrations of 1% or more in a product’s first aid statement. Neither regime does what Proposition 65 does: warn consumers about trace-level carcinogens and reproductive toxicants in everyday products.
The two regimes list different chemicals, set different thresholds, require different warning formats, and enforce through different mechanisms. A product that satisfies every Canadian labeling rule can still violate Proposition 65 if it contains a listed chemical above safe harbor exposure levels without a warning. For a Canadian company selling into California, building a separate Proposition 65 compliance process is the only reliable path.
One Boundary Worth Noting
Proposition 65 has a second prohibition that most Canadian businesses never encounter: it forbids knowingly discharging significant amounts of listed chemicals into sources of drinking water.1Office of Environmental Health Hazard Assessment. About Proposition 65 This applies to facilities operating in California. If your company has manufacturing or processing operations in the state, treat it as a separate compliance obligation; if you only ship finished product into California, product warnings are the piece that matters.