Those ubiquitous warnings — "This product can expose you to chemicals known to the State of California to cause cancer" — come from Proposition 65, formally the Safe Drinking Water and Toxic Enforcement Act of 1986 (Health & Safety Code § 25249.5 et seq.). For businesses, Prop 65 is less a chemistry problem than a litigation problem: private enforcers send thousands of 60-day notices every year, and settlements routinely run into five and six figures. Here is who must warn, when, and how to reduce the target on your back.
What Prop 65 actually requires
The statute has two operative prohibitions. First, a business may not knowingly and intentionally expose any individual to a chemical known to the state to cause cancer or reproductive toxicity without first giving a clear and reasonable warning. Second, a business may not knowingly discharge a listed chemical into a source of drinking water or onto or into land where it passes or probably will pass into such a source. The warning requirement is the one that reaches ordinary companies — manufacturers, distributors, retailers, restaurants, landlords, and e-commerce sellers alike.
The chemical list, maintained by California's Office of Environmental Health Hazard Assessment (OEHHA), now includes roughly 900 substances: lead, cadmium, phthalates, acrylamide, BPA, wood dust, and many more. Exposures count whether they come from a product, a workplace, or physical premises, which is why you see warnings in parking garages and coffee shops as well as on product labels.
The 10-employee threshold — and its limits
Prop 65's warning and discharge prohibitions do not apply to businesses with fewer than 10 employees. The count includes all employees, not just those in California, and part-time workers count. But small businesses should not relax too quickly:
- The exemption protects the small business itself, not its products downstream. A small manufacturer's goods can still trigger obligations for larger retailers who sell them — and those retailers push the compliance burden (and indemnity demands) back up the supply chain by contract.
- Companies hovering near 10 employees should track headcount carefully; crossing the line switches the statute on.
- Government agencies are also exempt, but few private sellers are.
There is also an exposure-level exemption: no warning is required if the business can show the exposure falls below the "no significant risk level" for carcinogens or the "maximum allowable dose level" for reproductive toxicants. The catch is that the burden of proof sits on the business, and proving low exposure requires testing and expert work — often after an enforcer has already sent a notice.
Safe harbor warnings: getting the words right
OEHHA regulations provide "safe harbor" warning content and delivery methods that are deemed clear and reasonable. Since 2018, the standard long-form warning must name at least one listed chemical for each applicable toxicity endpoint, include the warning triangle symbol (yellow unless the label does not use yellow), and cite www.P65Warnings.ca.gov. A short-form warning is permitted on product labels, and recent amendments (adopted effective January 1, 2025, with a multi-year phase-in) require even short-form warnings to identify at least one specific chemical for each applicable toxicity endpoint. Internet sellers must provide the warning on the product page, through a clearly marked hyperlink on that page, or otherwise prominently before purchase; catalog sellers must provide it in a manner that clearly associates it with the item. Businesses using old label stock or generic no-chemical-named short forms should plan their transition now rather than at the compliance deadline.
Enforcement: the 60-day notice machine
Prop 65 can be enforced by the Attorney General, district attorneys, and certain city attorneys — but the volume comes from private plaintiffs suing "in the public interest." A private enforcer must first serve a 60-day notice of violation on the business and public prosecutors. If no public agency takes the case, the private enforcer may sue for civil penalties of up to $2,500 per violation per day, plus potential attorney's fees, which are the true economic engine of these cases. Most matters settle with a payment, a fee award, and an injunction requiring reformulation or warnings. If you receive a 60-day notice, treat it as litigation: preserve documents, notify upstream suppliers and your insurer, and get counsel involved before responding.
Reducing your exposure before a notice arrives
- Map your product line against the OEHHA list, focusing on frequent-flyer categories: anything with lead or cadmium (metal parts, ceramics, jewelry), vinyl and plastics (phthalates), foods with acrylamide, and supplements.
- Get supplier representations, testing certificates, and indemnity provisions into your purchase agreements — your contracts are your first line of defense.
- Adopt safe harbor warnings where exposure is plausible; the warning costs little compared to defending its absence.
- Cover premises exposures too: parking structures, designated smoking areas, and certain workplace exposures have their own tailored warnings.
- Fold Prop 65 into your broader regulatory compliance program and revisit it when you add products, suppliers, or that tenth employee.
Talk to a California business attorney
Whether you are labeling a new product line or holding a fresh 60-day notice, early advice on Prop 65 usually saves multiples of its cost. Schedule a free consultation or call (949) 418-2113.
This article is attorney advertising and provides general information only. It is not legal advice and does not create an attorney–client relationship. Facts matter; consult a lawyer about your specific situation.
