California Prop 65 Warnings: What Online Sellers Must Put on Labels and Websites

If you sell a single product to a customer in California, a 1986 state law can reach into your warehouse — wherever that warehouse is — and fine you up to $2,500 per day, per product, for a missing sentence on your website. You do not need a California office, a California entity, or even a single California employee. You just need a California buyer and a product containing any of roughly 900 listed chemicals without a proper warning.

That law is Proposition 65, and private bounty-hunter lawyers filed a record volume of enforcement actions under it in recent years: more than 1,300 settlements totaling over $26 million in 2024 alone. Most cases never see a courtroom. They start with a 60-day notice letter and end with a settlement check — commonly $5,000 to $80,000 for a small seller — plus attorney's fees. The good news: compliance is mostly a labeling and website exercise, and the responsibility falls first on manufacturers and importers, not on every retailer down the chain. Here is how the rules actually work for online sellers and small retailers.

Who Has to Warn (and Who Is Exempt)​

Proposition 65 requires businesses with 10 or more employees to provide a "clear and reasonable warning" before knowingly and intentionally exposing a Californian to a listed chemical. Three points trip up small sellers:

The 10-employee threshold counts your whole business. Part-time staff count, and employees outside California count. If you have 12 people across two states, you are covered. Genuinely tiny operations with fewer than 10 employees are exempt — the most useful small-business carve-out in the law.

Out-of-state and online-only sellers are covered. The trigger is exposure inside California. If your Shopify store, Amazon listing, or Etsy shop ships to a California address, the law applies to that sale. You are allowed to limit warnings to California-bound products rather than warning the whole country, but most small sellers warn everywhere because geo-targeting warnings is more engineering than it is worth.

"Knowingly" does not mean what you hope it means. You cannot dodge the law by refusing to test your products. Courts have held that knowledge can come from public information — supplier disclosures, industry alerts, or a notice letter itself. Once a manufacturer tells you a product needs a warning, or a 60-day notice lands in your mailbox, you know.

Who in the Supply Chain Actually Owes the Warning​

This is the part most retailers get backwards. California's regulations place primary responsibility on manufacturers, producers, packagers, importers, suppliers, and distributors — not on retail sellers. An upstream business in those categories must do one of two things:

1. Put the warning directly on the product label or immediate packaging, or
2. Send a written notice plus warning materials to the authorized agent of the business it sells to, and get an acknowledgment of receipt back.

If your supplier does either of those properly, you as the retailer are generally off the hook — you just have to pass the warning through. But retailers become responsible in five situations you should memorize:

• You sell under your own brand. Private-label sellers, Amazon FBA sellers with their own brand, and anyone whose name is on the product is treated as the responsible party, not a mere retailer.
• You imported the product. Importers are upstream parties. If you source from an overseas factory, California treats you as the manufacturer for warning purposes — even if you are a two-person company.
• You introduced the chemical. Repackaging, refurbishing, or bundling that adds an exposure makes it yours.
• You covered up or failed to pass on a warning. Removing a supplier's label, or receiving a supplier notice and ignoring it, shifts liability to you.
• You have actual knowledge anyway. Marketplace operators learned this the hard way: once you know a product contains a listed chemical, the retailer's shield does not protect you.

There is one narrow mercy rule for retailers. If the only reason you know about an exposure is that you received a 60-day notice naming the product, you get five business days to fix it — either add the warning or pull the product — and that cure limits your exposure for that claim.

What this means for Amazon, Etsy, and Shopify sellers​

If you resell someone else's branded product and the brand handles warnings, your job is mostly to display them. But if you private-label, bundle, import, or manufacture — the standard Amazon FBA and Shopify playbook — you are the upstream party. Amazon's own seller terms say this explicitly: selling partners are responsible for Prop 65 compliance, and Amazon requires you to submit warning information through Seller Central so it can display the warning on your detail pages. A marketplace field is not a substitute for your own legal duty, but leaving it blank while shipping to California is close to an admission.

What the Warning Has to Say (and the 2028 Short-Form Change)​

A compliant "safe harbor" warning has specific required elements: the yellow triangle symbol with an exclamation point, the word WARNING in capital letters and bold print, the name of at least one listed chemical in the long-form version, the type of harm (cancer, birth defects or other reproductive harm), and the website www.P65Warnings.ca.gov.

For years, sellers loved the short-form warning — the one-liner ending in the P65 website with no chemical name — because it fit on small packages and crowded web pages. That version is now on a timer:

• You can use the new short-form language today. The revised short form names at least one chemical, e.g. identifying lead as the reason for the warning.
• Products manufactured and labeled before January 1, 2028 can keep the old short form and still hold safe harbor protection.
• On January 1, 2028, the new language becomes mandatory for anyone who wants safe-harbor protection from a short-form warning.

If you are ordering packaging with a long shelf life, print the new language now. Relabeling inventory in December 2027 is the expensive version of this decision.

Website warnings have their own rules​

For internet sales, the regulations offer three compliant methods, and you must pick at least one:

1. Put the full warning text on the product display page itself.
2. Put a clearly marked "WARNING" hyperlink on the product display page that leads to the warning.
3. Otherwise prominently display the warning to the buyer before they complete the purchase.

Two traps catch online sellers here. First, you may use the short-form warning online only if the same short-form warning also appears on the product or its packaging — a website-only short form does not earn safe harbor. Second, if you provide consumer information in a language other than English, the warning must appear in that language too. A Spanish-language product page with an English-only warning is a defective warning.

Warnings must also appear before checkout completes. A warning buried in a footer, hidden behind a tab nobody opens, or shown only in the order confirmation email arrives too late.

Which Products Actually Trigger Warnings​

The OEHHA list holds around 900 chemicals, but enforcement clusters around a familiar set of repeat offenders. Lead dominates the dockets — in jewelry, ceramics, brass fittings, cables and cords, vinyl bags, and imported housewares. Close behind are phthalates in vinyl and PVC products, BPA in plastics and can linings, formaldehyde in pressed-wood furniture, and heavy metals in cosmetics and supplements. A newer enforcement wave is forming around PFAS in food packaging and cookware.

Before panicking about your catalog, understand the two defenses that excuse a warning:

Below safe-harbor levels, no warning is due. OEHHA publishes No Significant Risk Levels for carcinogens and Maximum Allowable Dose Levels for reproductive toxicants. If the actual consumer exposure from your product falls below those levels, no warning is required. The catch: the burden is on you to prove it, which usually means lab testing or an exposure assessment — not a guess.

Naturally occurring chemicals in food are excluded. Lead that is unavoidably present in soil and taken up by a cocoa plant, for example, is treated differently from lead added during manufacturing. Food sellers should still get advice rather than self-certifying, because the line between natural and added is exactly where enforcers litigate.

Newly listed chemicals also come with a 12-month grace period before warnings are required, which is why monitoring OEHHA's listing notices belongs on someone's calendar — yours, your compliance consultant's, or your trade association's.

Common Mistakes That Turn Into Settlement Checks​

Reading enforcement patterns, the same errors appear over and over:

• Assuming the supplier handled it. Distributors routinely forward products with no warning and no written notice. If neither arrives, the duty can land on you. Ask every supplier for Prop 65 compliance statements or test reports, in writing, before you list the SKU.
• Warning only at checkout — or only in English. Both fail the "before purchase" and language rules described above.
• Treating "small seller" as "exempt seller." The under-10-employee exemption is real, but headcount includes everyone, everywhere. Many sellers who feel small are over the line.
• Forgetting marketplace attribute fields. Amazon, and increasingly other marketplaces, have dedicated Prop 65 fields. Fill them in, and make sure the listing-page warning matches the physical label.
• Over-warning everything. Slapping warnings on products that do not need them feels safe, but it trains customers to ignore warnings, can alarm buyers unnecessarily, and looks sloppy to wholesale partners. Warn where the law requires it; document why the rest of the catalog is clear.
• Ignoring the 2028 relabel deadline. Packaging ordered in 2026 with a multi-year run will still be on shelves when the old short form expires. Print forward-compatible labels now.

A Practical Compliance Checklist for Small Sellers​

Work through this once, then repeat it for every new SKU:

1. Triage your catalog. Flag high-risk categories: jewelry, ceramics, vinyl/PVC goods, cosmetics, supplements, children's products, brass and metal goods, cables, cookware, and anything imported.
2. Collect supplier paperwork. Request Prop 65 compliance letters, test reports, or material declarations for flagged SKUs. No paperwork means you assume the risk or test yourself.
3. Test what matters. Commission lab testing for your highest-volume or highest-risk products rather than the entire catalog. Keep reports filed by SKU.
4. Label the product. Use long-form warnings where space allows; use the new chemical-naming short form on small packages so you are already 2028-ready.
5. Fix the website. Add warnings or WARNING links to every flagged product display page, mirror non-English pages, and verify the warning renders before checkout on mobile — where most buyers actually shop.
6. Complete marketplace fields. Fill in Prop 65 attributes everywhere you sell, and keep screenshots with dates proving what the listing showed.
7. Keep a compliance file. Supplier notices, acknowledgments, test reports, label proofs, and listing screenshots, organized by SKU and date. This file is your settlement negotiator: documented good-faith compliance routinely shrinks demands.
8. Calendar OEHHA listings and January 1, 2028. New listings start 12-month warning clocks, and the short-form transition is a hard date.

If a 60-day notice arrives despite all this, do not ignore it — the 60-day clock is also your settlement window. Preserve your compliance file, stop the accused sales or add the warning immediately (retailers generally have five business days to cure when the notice was their first knowledge), and get a Prop 65 defense lawyer before responding. Early, documented cures are the single biggest lever on the final number.

Tracking Compliance Costs in Your Books​

Prop 65 compliance generates a paper trail of spending — lab testing fees, label redesigns, packaging reprints, website development time, supplier audits, and occasionally legal bills — and that spending deserves better than a pile of receipts. Lab testing and label reprints for products you already sell are generally ordinary and necessary business expenses, deductible when paid or incurred. Testing tied to developing a new product may need to be capitalized with the product's other development costs. Government penalties are not deductible, which is one more reason a cure beats a fine. Your CPA should bless the treatment, but the bookkeeping discipline is on you either way.

The practical move is to tag every compliance cost to the SKU or product line that caused it, so you can see which products earn their keep after testing and labeling. A product that needs a $600 lab panel, a packaging reprint, and an hour of developer time every time the warning language changes has a true margin well below what the purchase order suggests. Keep those costs in sub-accounts under testing, packaging, and professional fees rather than burying them in general supplies, and keep the test reports and label proofs alongside the transactions. When an enforcer's letter arrives two years later, the business that can pull the SKU file in minutes negotiates from strength. Plain-text accounting makes this easy: every cost is a dated, reviewable entry, and your compliance file and your ledger tell the same story. The inventory and cost-tracking workflows in the docs show how to structure product-level sub-accounts for exactly this kind of per-SKU tracking.

Simplify Your Financial Management​

Staying ahead of Prop 65 means tracking testing fees, label runs, and per-SKU margins as carefully as you track the warnings themselves. Beancount.io provides plain-text accounting that gives you complete transparency and control over your financial data — no black boxes, no vendor lock-in. Get started for free and see why developers and finance professionals are switching to plain-text accounting.