Trade · Seller compliance · Online sellers
Is a Prop 65 warning required for your product?
Answer five questions to see whether California's Proposition 65 warning duty reaches your business, and where the warning goes on a listing.
Proposition 65 requires a clear and reasonable warning before knowingly exposing California consumers to a listed chemical above the safe harbor level, but a business with fewer than 10 employees is outside the warning duty.
Your answers
Result
Answer the questions and press Check.
Worked example
A 25-person company sells ceramic mugs on its website and ships to California. A lab finds lead in the glaze and the calculated exposure exceeds the safe harbor level. The checker returns Warning required for California sales and notes that the warning must appear on the product page, in a link labelled WARNING, CA WARNING or CALIFORNIA WARNING, or otherwise prominently before the buyer completes the purchase. A two-person studio with the same mug is exempt on the employee test.
Before you start
The checker asks: How many employees does your business have; Do you offer or ship to California buyers; Does the product contain a Prop 65 listed chemical; Is consumer exposure above the safe harbor level; Where do you sell. Have your supplier paperwork, specification sheet and draft listing copy open, because each answer maps to a specific rule quoted below.
The result gives a verdict, the reasons behind it with the rule text it relied on, and next steps. Where your answers leave a real gap, it says "check" instead of guessing. Nothing you type leaves your browser, so you can try different answers to see how the verdict changes.
What the official source says
- Small-business exemption: Health and Safety Code 25249.11 excludes a person employing fewer than 10 employees from the definition of a person in the course of doing business. The statute page blocks automated fetches, so this was read from OEHHA's statute index and the code citation; confirm it on OEHHA's law page.
- Warning duty: Health and Safety Code 25249.6 requires a warning before knowingly and intentionally exposing a person to a listed chemical.
- Content: 27 CCR 25603 specifies a yellow triangle with an exclamation point, the header WARNING (or CA WARNING / CALIFORNIA WARNING), a message naming the harm (cancer or birth defects or other reproductive harm) and a link to www.P65Warnings.ca.gov. Source: 27 CCR 25603.
- Internet sales: 27 CCR 25602(b) requires the warning on the product display page, through a hyperlink so labelled, or otherwise prominently displayed before purchase; a warning the purchaser must search for does not qualify. Source: 27 CCR 25602.
All sources retrieved October 2026. Not covered: does not tell you which chemicals are in your product, calculate exposure, advise on a 60-day notice you may receive, or cover federal pre-emption of specific products. Test results and the OEHHA list decide. Rules change; the linked page governs.
Frequently asked questions
Does Prop 65 apply to businesses outside California?
The duty attaches to exposures of California consumers, so a seller that offers or ships to California can be covered wherever it is based.
How many employees exempt a business?
Fewer than 10 employees puts a business outside the warning duty under Health and Safety Code 25249.11.
Where does the warning go on an online listing?
On the product page, behind a link labelled WARNING, CA WARNING or CALIFORNIA WARNING on that page, or otherwise prominently before purchase.
What does the warning say?
It names the chemical and the harm and points to www.P65Warnings.ca.gov, in the format 27 CCR 25603 sets out.
Is this legal advice?
No. Prop 65 claims are litigated; ask a California attorney before deciding not to warn.
Not legal advice
This tool sorts the answers you enter against the regulator pages named on the page. It runs in your browser, stores nothing and does not decide your legal obligations. Rules change; confirm with the regulator or a qualified adviser.