# California Prop 65 importers guide: what US sellers must know
California Prop 65 is the regulation that puts warning labels on products sold in California when they can expose people to listed chemicals. For importers, it is one of those rules that stays invisible until it suddenly is not: a letter from a law firm, a marketplace compliance notice, or a retailer asking for documentation you do not have. This California Prop 65 importers guide explains what the rule requires, why it hits importers harder than domestic brands, and how to handle it without panic.
The short version: if your product is sold in California and contains a listed chemical above the relevant level, it needs a clear warning. The importer of record owns compliance, which means the responsibility lands on you, not your factory in China. Testing is batch-specific, documentation is everything, and the cost of getting it wrong can far exceed the value of the goods.
What Prop 65 actually requires
Proposition 65 is a California law requiring businesses to warn consumers about significant exposures to chemicals the state lists as causing cancer or reproductive harm. The practical effect for product sellers is a warning label on the product or its packaging when a listed chemical is present above the applicable threshold.
Two things about the structure matter for importers. First, the list is long and it grows; lead and phthalates are the ones importers encounter most often, but they are far from the only entries. Second, the law works through warnings rather than bans. That warning-first design is what makes this a labelling problem for California Prop 65 importers, not just a chemistry problem. A product that would be illegal under an outright restriction can be sold in California with the right warning. That sounds lenient until you consider what a cancer warning does to a consumer product's sales, which is why most brands aim to be below the thresholds rather than labelling their way out.
The warning has to be clear and reasonable, which in practice means visible at the point of sale or on the product itself, not buried in a manual. For goods sold online into California, the product page typically needs the warning too. Check the current official guidance from the state's administering office for the exact requirements in force when you ship, since the details move.
Why California Prop 65 catches importers off guard
Domestic US brands usually meet Prop 65 through their supply chain paperwork: material declarations from known suppliers, testing cadences, legal review. The compliance playbook that California Prop 65 importers need looks different from the domestic one, because they are buying from China with far less visibility. The factory's material choices are opaque, sub-suppliers change without notice, and the test report on file, if one exists, may describe a sample from two years ago. California Prop 65 importers discover the gap at the worst moment, when someone asks for proof.
Enforcement is the other surprise. Prop 65 is largely enforced through private lawsuits, which means specialised law firms actively look for products without warnings. That enforcement model is why California Prop 65 importers lose more sleep over this rule than over most federal ones. An importer with a few hundred units in a California warehouse is as visible as a national brand if the product is listed online. The economics of these cases favour quick settlements, which is why the letters keep coming.
There is also a compounding effect with other US rules. A children's product with lead above the limit is a CPSIA problem and a Prop 65 problem at once. Food-contact goods face FDA rules plus Prop 65. Each regime has its own testing and documentation, and passing one does not cover the others. Importers who treat "US compliance" as a single checkbox get caught in the gaps between the regimes.
California Prop 65 importers: the compliance workflow
Handling Prop 65 is a process, not a purchase. The workflow below is written for California Prop 65 importers working with Chinese factories, not for domestic brands with established supply chains.
Start with materials. List every material in your product and packaging that could contain a listed chemical: metals that could contain lead, soft plastics that could contain phthalates, coatings, inks, adhesives, and any recycled content. Your product spec sheet is the right place for this list. If you do not have a spec sheet with materials broken out, write one before you do anything else; it is the single source of truth that prevents "misunderstandings" with the factory later.
Test the actual production materials, not just the sample. When California Prop 65 importers skip straight to finished-goods testing, or skip testing entirely, the results are guesswork either way. Batch-specific test reports matter enormously here because material composition drifts between production runs. A report from an accredited lab such as SGS, Intertek, TUV, or Bureau Veritas, tied to the batch you are shipping, is the document that protects you. A generic certificate from the supplier, or a two-year-old report for a different production run, does not.
Decide on labelling deliberately. If testing shows listed chemicals above the threshold, you need the warning, placed where it will actually be seen. If testing shows you below the thresholds, document that decision with the test report behind it. The worst position is the middle one: no testing, no warning, and no paper trail. That is the position the enforcement letters are written for.
Build retesting into repeat orders. Materials change, sub-suppliers change, and a test report from the first order says nothing about the fifth. A retest cadence tied to your order cycle costs less than a single enforcement action. Put the testing requirement and the right to retest into your manufacturing contract or purchase terms so it is agreed before a dispute, not during one.
The cost of getting it wrong
The direct costs are settlements and legal fees, which arrive faster than most importers expect. But the larger cost is often the recall. If a product already in distribution turns out to need a warning it does not carry, or worse, contains a chemical at levels that trigger stronger action, pulling it back through the supply chain is expensive. Recall cost can far exceed the value of the goods themselves, especially for low-margin imported products where the logistics cost more than the merchandise.
Then there is the channel damage. Marketplaces and retailers have their own compliance teams, and a Prop 65 flag on your product can mean delisting while you sort out documentation. The recall math is the part of California Prop 65 importers remember longest: pulling goods back through the chain routinely costs more than the goods were worth. For Amazon sellers, a compliance hold during a selling season costs sales you never recover. None of this requires the product to be dangerous in any practical sense; it requires the paperwork to be missing.
The lesson California Prop 65 importers take from this is not that California is unreasonable. It is that compliance has to be built into sourcing from the start, when testing is cheap and labels are easy to add, rather than bolted on after someone complains.
Prop 65 and your supplier relationship
Your factory did not create Prop 65 and does not think about it. That is fine; it is your job, not theirs. What you need from the supplier is cooperation with your process: material declarations for components, advance notice of material or sub-supplier changes, and access for testing.
Put the requirements in writing. The spec sheet should name restricted substances and the testing standard the goods must meet. The QC checklist should include label verification: is the warning present, legible, and correctly placed on the units actually shipping? A pre-shipment inspection is the last point where a missing warning can be fixed cheaply; once the container leaves, every option gets expensive.
Choose suppliers with export experience in regulated categories. The factories that make life easy for California Prop 65 importers are the ones that already sell into regulated markets. A factory that already sells into the US or EU understands material declarations and batch testing as routine. A factory whose customers never asked will treat your requirements as exotic, and you will spend the relationship educating them. Neither is disqualifying, but California Prop 65 importers should price the effort accordingly.
Conclusion
California Prop 65 importers handle best when they treat it as a sourcing process rather than a legal surprise. Map your materials, test the actual production batches through an accredited lab, make a deliberate labelling decision, document everything, and retest on a cadence. The importers who get hurt are not the ones with risky products; they are the ones with no paper trail when the letter arrives. Build the trail before you need it.
FAQ
### Does Prop 65 apply if I only sell online?
Yes, if your products reach California consumers. Online sales into California count. The warning typically needs to appear on the product page as well as on the product or packaging.
### Is a Prop 65 warning the same as a ban?
No. Prop 65 requires warnings, not bans. A product with a listed chemical above the threshold can be sold with a proper warning. Most brands still aim to stay below thresholds because warnings hurt sales.
### My supplier says the product is "Prop 65 compliant." Is that enough?
No. A supplier's verbal assurance is not documentation, and California Prop 65 importers need batch-specific test reports from an accredited lab, tied to the materials and the production run being shipped.
### Where can I check the current Prop 65 chemical list?
California Prop 65 importers should check the current official list maintained by the state's administering office before finalising materials, since the list grows over time. Do not rely on a supplier's copy of the list or a blog post from two years ago.
### How is Prop 65 different from CPSIA?
CPSIA is a federal law covering children's products, with lead and phthalate limits, mandatory third-party testing, and a Children's Product Certificate. Prop 65 is a California law covering all consumer products, working through warning labels for a much longer chemical list. A children's product sold in California can fall under both at once.