California Prop 65 for Online Sellers: Who Must Warn and How
If you sell consumer products that reach California buyers, Proposition 65 can apply to you even if your company is based in China or another state. A missing warning can lead to a "60-day notice," a settlement demand and civil penalties. This guide explains who must warn, how online warnings work, and the dates and numbers that matter, based on official California guidance.
What Prop 65 requires
According to the OEHHA Frequently Asked Questions for Businesses, businesses must provide a "clear and reasonable" warning before knowingly and intentionally exposing anyone to a chemical on the Proposition 65 list, unless they can show the exposure will not pose a significant risk of cancer or is significantly below levels observed to cause birth defects or other reproductive harm. The list covers chemicals known to cause cancer or reproductive harm, and businesses decide for themselves whether their products need a warning.
Two points sellers often miss:
- Out-of-state online sellers are not exempt. The FAQ says Prop 65 "applies to all businesses with 10 or more employees doing business in California," including out-of-state internet retailers.
- Small businesses may still be affected. Companies with fewer than 10 employees are exempt from the warning rules, but OEHHA notes they may still have contractual or indemnification obligations, for example to a retailer or marketplace.
Key numbers and deadlines
| Rule | Number or deadline | Source |
|---|---|---|
| Businesses covered | 10 or more employees (full- and part-time counted) | OEHHA FAQ, 27 CCR 25102(h) |
| Warning required after a chemical is listed | 1 year | OEHHA FAQ |
| Minimum font for a short-form label warning | 6-point | OEHHA FAQ, 27 CCR 25602(a)(4) |
| Supplier's written notice to a retailer | Renew at least annually | OEHHA FAQ, 27 CCR 25600.2(b)(4) |
| Retailer updates online short-form warning after supplier notice | Up to 60 calendar days | OEHHA FAQ, 27 CCR 25602(b)(2) |
| Retail seller corrects after a 60-day notice (if it only learned from the notice) | 5 business days | OEHHA FAQ, 27 CCR 25600.2 |
| New short-form content mandatory for products made on or after | January 1, 2028 | OEHHA FAQ |
| Maximum civil penalty | Up to $2,500 per day for each violation | California Attorney General FAQ |
Sources: OEHHA business FAQ and California Attorney General Prop 65 FAQ.
Who has to provide the warning
OEHHA's regulations place primary responsibility on manufacturers, producers, packagers, importers, suppliers and distributors. Under 27 CCR 25600.2, they must either put the warning on the product label or labeling, or send written notice and warning materials to the retailer's authorized agent and get an acknowledgment. Retail sellers are responsible for placing and maintaining the warning materials they receive. For a Chinese factory or brand selling through US retailers or marketplaces, that usually means you are expected to provide the warning.
How online warnings work
For internet sales, the FAQ says a product needs both a warning on or with the product and a warning online. The website must display the warning on the product display page, include a clearly marked hyperlink using the word "WARNING," or otherwise prominently display it "prior to completing the purchase." OEHHA gives the example of a pop-up shown when a buyer enters a California ZIP code. If the label uses a short-form warning, the website may use the same short-form content.
Short-form warnings: the 2028 change
The short-form warning is a shorter label version with the yellow warning symbol. According to OEHHA, products manufactured and labeled before January 1, 2028 can use the prior short-form or the new one. From January 1, 2028, the new language is required to keep safe harbor protection, and it must name at least one listed chemical for each health effect (cancer or reproductive harm). A short-form label warning cannot be smaller than 6-point type.
If you are printing packaging now for products that will still be manufactured in 2028, switching to the new short-form content today avoids a second packaging change.
Practical checklist
- Check your materials (plastics, coatings, metals, dyes) against the current Prop 65 list with your supplier or a testing lab.
- Decide: reformulate to avoid the chemical, or warn. The Attorney General's FAQ confirms reformulating is an option.
- If you warn, use the safe harbor content and add the warning to both the label and every online listing that can ship to California.
- If you sell through retailers, send written notice and warning materials, get an acknowledgment, and renew it at least once a year.
- Keep records of test reports, notices and listing screenshots.
- Align Prop 65 work with your other compliance steps: country-of-origin marking, CPSC product certificates and liability insurance.
- If you receive a 60-day notice, act fast and consult a California attorney.
How Atronia Innovations helps
We help Chinese factories and brands entering the US prepare compliant listings and packaging details for Amazon, Walmart and TikTok Shop, and coordinate with your compliance advisors. This guide is general information, not legal advice. See our Brand Accelerator or contact us.
