Prop 65 Warning Label Requirements: What to Ask Your Factory For

Alan Xiao Founder, Sourcing Pioneer

· Updated October 24, 2026 · 11 min read

the state's Prop 65 asks a business to warn people before they touch a product that carries a listed substance. The warning is a label, not an approval. That single fact explains most of the confusion in this category, because buyers keep asking factories for a certificate that cannot exist. Here is what the rule asks for, which parts usually trigger it, and what to put in the file instead.

The Short Answer

Four things are true at once. A buyer needs all four before talking to a supplier.

Each one changes what you ask for in the first email. Together they set the questions you send the factory. Nothing here needs a lawyer, only a checklist.

The rule is a warning duty, not a ban. A product with a listed substance can still be sold in the state, as long as the warning reaches the buyer first.

There is no certificate of the rule, because there is nothing to approve. A factory that offers you a "Prop 65 certificate" is selling you a letter with no legal weight.

What you can hold is evidence: part declarations, lab test per part, and the label artwork with its revision. That is the file a buyer needs if a letter ever arrives.

The state pages carry the current list, formats and enforcement detail. Read the warning formats page for the exact wording, because it changes and this page does not reproduce it.

What the Rule Actually Asks For

Strip out the history and four mechanics remain.

Who warns

A business selling into the state. Size and turnover decide how the duty applies, and the state FAQ sets out the current position.

What triggers it

A substance on the state list, present above the level the state treats as safe for that substance. No list, no duty.

What the warning says

The substance name, the harm it is linked to, and a web address for more detail. A short form drops the substance name.

Where it goes

On the product, on its pack, or both. A sale online needs the warning visible on the page too.

The practical weight sits in the second item. The list is long, and it covers metals, solvents and plasticisers that appear in ordinary goods. A factory cannot tell you whether your item crosses a level. Only a test on the part can.

The Certificate Question

This is the most common error in the category, so it is worth being blunt.

A supplier who says "we meet Prop 65" has told you nothing you can use. The rule asks for a warning where one is needed. The state does not issue a mark, a number or a certificate for that.

What a supplier can give you is a part list, a lab test, and the label. Ask for all three, and treat a letter as a substitute for none of them.

The same logic applies to the word "certified". A lab can certify that a sample of a part held a certain amount of a substance. That is a test result about a part, and it is useful. It is not a statement about your product.

Which Materials Usually Trigger It

Four parts account for most of the warnings on consumer goods sourced from China. The pattern is stable enough to plan around.

Two details decide whether a test is worth the money. The first is which layer is tested. Lead sits in paint far more often than in the steel under it, so a substrate test can pass while the surface fails.

The second is colour and compound. A factory may run five colours from three suppliers. One passing test covers one compound, and the other colours remain unknown until each is tested.

Testing: By Material, Not by Product

A product-level lab test looks reassuring and answers a narrower question than buyers think. It test on the sample submitted, which is one item from one run.

Materials are what carry the risk, so build the test plan from the bill of parts. List each part, each colour and each supplier. Then decide which ones need a test. A five-part product can need three tests or eight, and the difference is cost, not caution.

Two rules keep the plan honest. Test every colour of a coated or printed surface, and test every alloy batch you will actually ship. A test tied to a batch that was consumed two orders ago tells you about history.

The test also needs to name the part and the method. A page of numbers with no part name cannot be matched to anything, and it will not help if a notice arrives a year later.

Long Form, Short Form, and Where It Goes

The long form names the substance. The short form does not, and exists so that a small item can carry something legible.

That is a real trade-off, not a free option. A short-form label on a pair of earrings may be the only version that fits. It also removes the one piece of information a worried customer wants.

Placement is the part that gets skipped. The warning belongs on the product or the pack, and a sale made on a website needs it on the page as well. Many sellers print the label and forget the listing, which is the version most buyers actually see.

Put the label artwork in the specification sheet with a revision number. A factory that reprints pack between orders will otherwise use whatever file it still has. The spec sheet a Chinese factory builds from is the right place for artwork, and the place a buyer forgets to put it.

A pack can carry the long form while the item carries the short one. That combination solves most space problems.

It also doubles the artwork you have to track. One revision per surface, or the next printing runs on the old file.

What to Keep in the File

If a notice ever arrives, the file decides how the next month goes. Five items are enough.

Material list

Every part in the product, with supplier and colour, so a test can be traced to a part.

Test test

One per part and colour tested. Each names the part, the method and the sample date.

Label artwork

The file sent to the printer, with its revision and the date it was approved.

Photo of the finished label

A photo of a production unit, because artwork and print are not always the same thing.

Shipment records

Which lots carried which label, so you can show what was sold when.

The photo is the item most buyers skip and the one that settles arguments fastest. It shows what actually left the factory, and it costs nothing to take during an inspection before the cartons close.

Keep the parts list with the order file. It is the most useful document you will own. It is short, it is cheap to make, and it answers the only question that matters. What is in this product.

Ask for it in writing, with a supplier name for each part. A list that says "plastic" is not a list.

Then check it against the sample. A factory that added a part after the quote will not offer the news.

Two buyers can hold the same test and reach different answers. One tested the coating. The other tested the steel under it.

That is not a lab error. It is a question of what was sent.

Write the part name on the test request. Then the result can be matched to a line in the parts list, years later.

Four Mistakes That Repeat

The first is accepting a letter in place of a test. It arrives fast, it looks state, and it proves nothing about the goods.

The second is testing one colour of a five-colour range. The other four remain unquantified, and a single complaint can reach any of them.

The third is a label that names no substance on a product that needs the name. The short form is legal in the right setting, and it is the wrong choice when the item is large enough for the long form.

The fourth is no label at all on a product that already carries a listed substance. That is the case where a warning duty was skipped entirely, and it is the one that produces letters.

Where This Sits for a Buyer

None of this asks you to become a rule expert. It asks you to buy the right documents at the right moment, and to keep them.

The moment is before the first bulk order. Testing after the goods land tells you what you already shipped. If the order itself is still a plan, start with the route from design to a first production run. Fold the part list into it.

Material testing is a different job from the visual checks most buyers run. A fabric and component check at the mill catches defects; a lab test catches lab work. Both belong in the same file, and neither replaces the other.

How a Case Usually Starts

It rarely starts with a regulator. It starts with a letter.

An outside party sends a notice to the seller. The notice names the product and the substance. It says a warning was missing.

The seller then has a short window to respond. Most cases end in a settlement, and most settlements are small. The cost sits in the disruption, not the sum.

This is why the file matters more than the label. A seller who can show a part list, a test and a printed label has a different conversation from one who cannot.

It is also why the cheapest route is boring. Test the parts that carry risk. Print the label. Keep the paperwork. Repeat on the next order.

A small order is not a safe order. The label duty does not care how many units you bought.

It also does not care who touched the product first. If your name is on the sale, the duty is yours.

That is why a buyer should decide the label before the artwork is approved. Changing a label after printing costs more than testing a part.

Questions Buyers Ask About Prop 65

The Bottom Line

Prop 65 is a warning duty that follows the product. The label tells a buyer what a part contains, and no authority approves it in advance.

So the work sits with you, and it is mostly paperwork. Name the parts, test the ones that carry risk, print the label where people will see it, and keep the file.

Ask a factory for a certificate and you get a letter. Ask for a part list, a test per part and the label artwork, and you get a file you can defend.