The California Proposition 65 chemical list is a state-maintained catalog of nearly 900 substances that California has identified as causing cancer or reproductive harm. It is published by the Office of Environmental Health Hazard Assessment (OEHHA) under the Safe Drinking Water and Toxic Enforcement Act of 1986, and it must be revised and republished 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 provide a warning, and the list drives billions of dollars in compliance costs and private enforcement activity each year.
Where to Find the Current List
OEHHA publishes the full list on its website as a searchable online 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.1Office of Environmental Health Hazard Assessment. Proposition 65 List of Chemicals The Excel version also shows how each chemical was added and whether OEHHA has adopted a safe harbor exposure level for it.
The list is formally codified at Title 27 of the California Code of Regulations, Section 27001.1Office of Environmental Health Hazard Assessment. Proposition 65 List of Chemicals Chemicals can be added at any point during the year, so check for recent additions instead of relying on an older downloaded copy.
What Kinds of Chemicals Are on It
Every substance falls into one of two categories: chemicals known to cause cancer, and chemicals known to cause reproductive harm, including birth defects. Some chemicals appear under both categories. The list ranges across heavy metals like arsenic and lead, industrial solvents, pesticides, pharmaceutical ingredients, and compounds that form naturally during food processing.
How Chemicals Get Added and Removed
California law defines four separate paths for adding a chemical to the list: a determination by one of two state scientific panels (the Carcinogen Identification Committee or the Developmental and Reproductive Toxicant Identification Committee); an automatic Labor Code listing when the International Agency for Research on Cancer identifies a substance as causing cancer; a formal identification by a designated Authoritative Body such as the U.S. EPA, the FDA, the National Toxicology Program, or NIOSH; and a listing driven by a state or federal labeling requirement, used mostly for prescription drugs.3Office of Environmental Health Hazard Assessment. How Chemicals Are Added to the Proposition 65 List All four paths include public notice and a comment period before the listing becomes final.
Chemicals can also be delisted through a process OEHHA calls reconsideration, which requires public notice, a comment period, deliberation, and a final decision.4Office of Environmental Health Hazard Assessment. Mechanisms for Listing and Delisting Chemicals Under Proposition 65 Delistings are rare. The evidence burden is substantial and the process can take years.
When a Warning Is Required
The core obligation is simple: no covered business may knowingly expose anyone in California to a listed chemical without first providing a “clear and reasonable” warning.5California Legislative Information. California Health and Safety Code HSC Division 20 Chapter 6.6 Section 25249.6 The warning duty kicks in 12 months after a chemical is added to the list, giving businesses time to reformulate products, test exposure levels, or update labels. A separate prohibition on discharging listed chemicals into drinking water sources takes effect 20 months after listing.6Office of Environmental Health Hazard Assessment. The Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65) A Summary
The law applies to every business with ten or more employees that does business in California, wherever the company is physically located.7Proposition 65 Warnings Website. Frequently Asked Questions for Businesses A company in another state or another country that sells products to California consumers has the same warning duty as one headquartered in Los Angeles. Each business must review the list itself and decide whether its products or operations are likely to expose Californians to listed chemicals above the thresholds.8Office of Environmental Health Hazard Assessment. Businesses and Proposition 65
Who and What Is Exempt
Businesses with fewer than ten employees are completely exempt from the warning requirement and the discharge prohibition. Government agencies at the local, state, and federal level, along with public water system operators, are also exempt.9California Legislative Information. California Health and Safety Code Section 25249.11
For covered businesses, the most common way out of a warning is a safe harbor exposure level. OEHHA has set two kinds.10Office of Environmental Health Hazard Assessment. Proposition 65 No Significant Risk Levels and Maximum Allowable Dose Levels For carcinogens, the No Significant Risk Level (NSRL) is the exposure calculated to produce no more than one excess case of cancer per 100,000 people over a lifetime of exposure.11Legal Information Institute. California Code of Regulations Title 27 Section 25703 – Quantitative Risk Assessment For reproductive toxicants, the Maximum Allowable Dose Level (MADL) is the no-observable-effect level divided by 1,000. Exposure below the applicable threshold does not require a warning.
Not every listed chemical has an established safe harbor level. When none exists, the business must show that anticipated exposure poses no significant cancer risk or falls well below levels observed to cause reproductive harm. OEHHA discourages unnecessary warnings and recommends consulting a qualified professional before deciding.8Office of Environmental Health Hazard Assessment. Businesses and Proposition 65
A narrower exemption covers listed chemicals that occur naturally in food. The business must prove the chemical is genuinely “naturally occurring” as defined by OEHHA’s regulations 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 does not qualify, even if lead also appears naturally in the soil where the crop was grown.
What a Compliant Warning Looks Like
To qualify for safe harbor protection from lawsuits, a warning must 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 may appear in black and white.
Warnings can take several forms depending on the exposure: a label on the product for consumer goods, a posted sign for occupational exposures, or a notice on a website’s product listing page for online sales.7Proposition 65 Warnings Website. Frequently Asked Questions for Businesses
2025 Short-Form Warning Changes
OEHHA adopted new regulations effective January 1, 2025, that change the rules for short-form warnings, the abbreviated labels used when space is limited. Short-form warnings must now name at least one chemical, making them more informative than the older generic versions. Businesses using the old short-form format have a three-year transition, meaning full compliance is required by January 1, 2028.14Office of Environmental Health Hazard Assessment. Proposition 65 Clear and Reasonable Warnings – Safe Harbor Methods and Content The updated regulations also add tailored safe harbor warnings for specific product categories, including motor vehicle parts and recreational marine vessel parts. Online retailers get a 60-day window after receiving notice from a manufacturer to update short-form warnings on their sites.
Penalties and Private Enforcement
A business that violates the warning requirement or the discharge prohibition faces civil penalties of up to $2,500 per day for each violation, on top of any other penalties available under law. Because the structure is daily and per-violation, a single product sold continuously across California can generate substantial potential liability in a short time.
The most distinctive feature of Proposition 65 is that it does not depend on government regulators. Any private individual or organization can enforce the law by filing a lawsuit in the public interest. Before filing, the private enforcer must serve 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.16California Office of the Attorney General. Initial Statement of Reasons – Division 4 Proposition 65 Private Enforcement Thousands of 60-day notices are filed each year. Most cases settle, and settlements frequently include testing costs and legal fees on top of the penalty split. Businesses that ignore 60-day notices or assume they are frivolous often pay far more than compliance would have cost.
Online and Out-of-State Sellers
If a product is available for purchase by California consumers online, the seller must ensure a compliant warning reaches the buyer before the exposure occurs. The warning generally needs to appear on the product listing page itself, not buried in terms of service the buyer is unlikely to read.7Proposition 65 Warnings Website. Frequently Asked Questions for Businesses
Responsibility can shift between manufacturers, distributors, and retailers depending on who controls the labeling and who knows about the chemical exposure. A retailer that receives a compliant warning label from its supplier and passes it along to consumers is generally in a stronger position than one that strips or ignores the manufacturer’s label. Under the 2025 amendments, online retailers have 60 days after receiving notice from a manufacturer to update short-form warnings on their sites.14Office of Environmental Health Hazard Assessment. Proposition 65 Clear and Reasonable Warnings – Safe Harbor Methods and Content