The California Proposition 65 list is a state-maintained catalog of nearly 900 chemicals that California has identified as causing cancer, reproductive harm, or both. It is published by the Office of Environmental Health Hazard Assessment (OEHHA) under the Safe Drinking Water and Toxic Enforcement Act of 1986 and is updated at least once a year.1Office of Environmental Health Hazard Assessment. Proposition 65 List of Chemicals Any business with ten or more employees that exposes people in California to a listed chemical above the applicable threshold must give those people a warning first.
Where to Read the Official List
OEHHA posts the full list on its website as a searchable table and as a downloadable PDF or Excel file.2Office of Environmental Health Hazard Assessment. The Proposition 65 List Each entry shows the chemical name, its Chemical Abstracts Service (CAS) registry number, and whether the chemical is listed for cancer, reproductive harm, or both. The Excel version also shows how the chemical was listed and whether OEHHA has set a safe harbor exposure level for it.
The list is formally codified at Title 27 of the California Code of Regulations, Section 27001. Because chemicals can be added at any time during the year, a downloaded copy goes stale quickly. Check the official page before relying on it.
What Is on the List
Every substance falls into one or both of two categories: chemicals known to cause cancer, and chemicals known to cause reproductive harm, including birth defects. The scope is broad. Heavy metals like arsenic and lead sit on the list alongside industrial solvents, pesticides, pharmaceutical ingredients, and compounds that form naturally during food processing.
Chemicals get added through four separate paths defined by California law: a finding by one of two state scientific panels (the Carcinogen Identification Committee or the Developmental and Reproductive Toxicant Identification Committee); automatic listing of substances the World Health Organization’s International Agency for Research on Cancer identifies as causing cancer, as required by California Labor Code Section 6382; formal identification by designated “Authoritative Bodies” such as the U.S. EPA, the FDA, the National Toxicology Program, and the National Institute for Occupational Safety and Health; and a federal or state requirement that a product carry a cancer or reproductive-harm warning, a path used mostly for prescription drugs.3Office of Environmental Health Hazard Assessment. How Chemicals Are Added to the Proposition 65 List
Chemicals can be removed through a “reconsideration” process that requires public notice, a comment period, and a final decision.4Office of Environmental Health Hazard Assessment. Mechanisms for Listing and Delisting Chemicals Under Proposition 65 Delistings are rare and the evidence burden is substantial.
Who Has to Comply
The warning requirement applies to every business with ten or more employees that does business in California, no matter where the company is based.5Proposition 65 Warnings Website. Frequently Asked Questions for Businesses A company in another state or another country that sells to California consumers is on the hook the same way a Los Angeles company is. Each business is responsible for reviewing the list and figuring out whether its products or operations expose anyone in California to a listed chemical above the relevant threshold.6Office of Environmental Health Hazard Assessment. Businesses and Proposition 65
Online sellers face the same obligation. If a product can be bought by a California consumer online, a compliant warning has to reach that buyer before the exposure happens, which means on the product listing page rather than buried in terms of service.5Proposition 65 Warnings Website. Frequently Asked Questions for Businesses Responsibility for the warning can shift among manufacturers, distributors, and retailers depending on who controls the labeling and who knows about the exposure.
When a Warning Is Required
The core rule: no business may knowingly expose anyone to a listed chemical without first providing a “clear and reasonable” warning.7California Legislative Information. California Health and Safety Code HSC Division 20 Chapter 6.6 Section 25249.6 The obligation kicks in 12 months after a chemical is added to the list. A separate rule prohibits discharging listed chemicals into drinking water sources, with a 20-month grace period after listing.8Office of Environmental Health Hazard Assessment. The Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) A Summary
A warning is not required if the exposure stays below OEHHA’s safe harbor level for the chemical.9Office of Environmental Health Hazard Assessment. Proposition 65 No Significant Risk Levels and Maximum Allowable Dose Levels For carcinogens, the safe harbor is the No Significant Risk Level (NSRL), set at the exposure calculated to produce no more than one excess case of cancer per 100,000 people over a lifetime.10Legal Information Institute. California Code of Regulations Title 27 Section 25703 – Quantitative Risk Assessment For reproductive toxicants, it is the Maximum Allowable Dose Level (MADL), the no-observable-effect level divided by 1,000. Not every chemical on the list has a safe harbor level. When none exists, the business bears the burden of proving its exposure poses no significant cancer risk or falls well below levels observed to cause reproductive harm.
Other Exemptions
Businesses with fewer than ten employees are exempt from both the warning requirement and the discharge prohibition. Government agencies at every level and public water system operators are also exempt.11California Legislative Information. California Health and Safety Code Section 25249.11
Chemicals that occur naturally in food can be exempt, but the standard is narrow. The business must prove the chemical is genuinely “naturally occurring” under OEHHA’s definition and that the level has been reduced to the lowest amount currently feasible.12California Office of the Attorney General. Proposition 65 Frequently Asked Questions Lead that leaches into food from processing equipment would not qualify, even if lead also appears naturally in the soil.
What a Compliant Warning Looks Like
To get “safe harbor” protection from lawsuits, a warning has to identify the type of harm (cancer, reproductive harm, or both), name at least one listed chemical responsible, use the word “WARNING” in capital letters, and include a black exclamation point inside a yellow triangle placed to the left of the warning text.13Proposition 65 Warnings Website. Where Can I Get Information on the Warning Symbol If the label is not printed in color, the triangle can appear in black and white. The warning can take different forms depending on the exposure: a product label, a posted sign at a workplace, or a notice on a product’s online listing page.
2025 Short-Form Warning Changes
OEHHA regulations effective January 1, 2025 changed the rules for short-form warnings, the abbreviated labels used when space is limited. Short-form warnings now must include at least one chemical name, so the older generic version no longer qualifies for safe harbor. Businesses using the old format have a three-year transition period, with full compliance required by January 1, 2028.14Office of Environmental Health Hazard Assessment. Proposition 65 Clear and Reasonable Warnings – Safe Harbor Methods and Content The amendments also create tailored safe harbor warnings for specific product categories, including motor vehicle parts and recreational marine vessel parts, and give online retailers 60 days after receiving notice from a manufacturer to update short-form warnings on their sites.
Penalties and the 60-Day Notice
Violating the warning requirement or the discharge prohibition exposes a business to civil penalties of up to $2,500 per day for each violation, on top of other penalties available under law. For a product sold continuously across California, that daily-per-violation structure stacks fast.
Proposition 65 is enforced largely by private parties, not just government regulators. Any individual or organization can sue in the public interest after serving a 60-day notice of violation on the business, the California Attorney General, the relevant district attorney, and the city attorney where the violation occurred.15California Office of the Attorney General. 60-Day Notice of Violation If a public agency begins prosecuting during that 60-day window, the private suit cannot proceed.
Private enforcers receive 25 percent of any civil penalty collected, plus attorney’s fees, and thousands of 60-day notices are filed every year.16California Office of the Attorney General. Initial Statement of Reasons – Division 4 Proposition 65 Private Enforcement Most cases settle, often with payment for testing costs and legal fees on top of the penalty split. A business that receives a notice and treats it as frivolous usually pays far more than compliance would have cost.