Prop 65 Short-Form Warnings: The January 1, 2028 Cutoff and Who Applies the Warning When You Relabel or Kit at a 3PL

By Bernardo Campelo, Forbes Business Council E-Commerce Leader, Amazon SPN Certified provider, Amazon SP-API authorized partner, and Founder of PrepVia.

As of October 29, 2026, California's Proposition 65 rules put a fixed date on the old short-form warning. Under 27 CCR 25603(c), as amended in the final regulatory text published by the Office of Environmental Health Hazard Assessment (OEHHA), a short-form warning on a product "manufactured and labeled prior to January 1, 2028" may keep the old content "regardless of when the product is sold to a consumer." Any other short-form warning has to use the new content, which names a chemical.

The amendments were filed on November 26, 2024 and took effect on January 1, 2025, according to the California Regulatory Notice Register of December 6, 2024. For a brand, that makes 2028 a packaging decision; for anyone whose units get a new consumer label or a kit box at a 3PL, it is also a work-order decision. This guide explains what the rules say and is not legal advice: whether a product needs a warning, and which chemical it names, is a question for your counsel.

Every date, rule and name below was checked on October 29, 2026 against OEHHA's published regulation text and its 2024 statement of reasons, California's Regulatory Notice Register, the Health and Safety Code, and Amazon's Seller Central help pages and Business Solutions Agreement, linked where they first appear. Amazon edits its help pages without notice and OEHHA has a draft package in discussion, so open the live page before you act.

What Changed on January 1, 2025

Before 2025, a product label could carry a short warning made of the yellow triangle, the word "WARNING:", and one of three phrases: Cancer, Reproductive Harm, or Cancer and Reproductive Harm, followed by the P65Warnings.ca.gov address. It named no chemical, and the 2024 rulemaking deleted the sentence that allowed it to skip the chemical name.

The general rule is in 27 CCR 25601(b), and the 2024 rulemaking removed its exception for the short form: a safe harbor warning includes "the name of one or more of the listed chemicals" in the product, with a chemical for each endpoint when it warns for both cancer and reproductive toxicity, unless one named chemical is listed for both. These are safe harbor warnings: OEHHA's October 2024 final statement of reasons notes that businesses "are not legally required to follow the safe harbor warning regulations," though many use them for the protection they give. The old wording survives only as a transition, in 25603(c). OEHHA's unofficial June 2024 copy of the proposed text left the end date blank for the Office of Administrative Law to insert the date "three years after the effective date of the 2023 amendments," and the final text set it at January 1, 2028.

What the New Short Form Has to Say

Section 25603(b) keeps the yellow triangle and lets the label use "WARNING:", "CA WARNING:" or "CALIFORNIA WARNING:" in capital letters and bold print. For a carcinogen, the sentence is "Cancer risk from exposure to [name of chemical]. See www.P65Warnings.ca.gov." or "Can expose you to [name of chemical], a carcinogen. See www.P65Warnings.ca.gov." For a reproductive toxicant, the same two forms are built around "Risk of reproductive harm" and "a reproductive toxicant," and the rule adds matching versions for both kinds of chemical and for one chemical listed for both endpoints. Food, including dietary supplements, has its own short form in 25607.2(b), with the same signal words and a named chemical but the www.P65Warnings.ca.gov/food address.

Type size changed too. The old requirement that the short form be no smaller than the largest type used for other consumer information on the product was deleted. Section 25602(a)(4) now asks for a type size that meets the conspicuousness test in 25601(c), and keeps the floor: "In no case shall the warning appear in a type size smaller than 6-point type."

That test applies to every consumer product warning under these rules: it has to be displayed so as "to render the warning likely to be seen, read, and understood by an ordinary individual under customary conditions of purchase or use." Keep that sentence in mind when a product goes into a kit box.

The Manufactured-and-Labeled Date Decides, Not the Sale Date

Read 25603(c) with both verbs. The old content is allowed only on a product that was manufactured and labeled before January 1, 2028. A unit that meets both conditions can sell in 2029 with the old warning, because the rule applies "regardless of when the product is sold to a consumer." OEHHA's statement of reasons says the sell-through gives businesses certainty, "so they do not have to recall products or relabel products that are already produced or in the stream of commerce."

The flip side matters to anyone who puts a new consumer label or a kit box on a unit after it is made. In our reading, a unit manufactured in 2027 that gets a new consumer label, or goes into a kit with a new kit label, on or after January 1, 2028 was not both manufactured and labeled before that date, so a short-form warning on the new label has to use the new content. An FNSKU sticker that carries no warning and covers none is a different case: in our reading, it does not take a unit out of the sell-through.

Packaging follows the same date. OEHHA declined to extend the sell-through "to preprinted labels or packaging," so a print run, kit box or replacement label that carries a short form needs the new content if it goes on a unit on or after January 1, 2028, or on a unit manufactured from that date, even if it was printed earlier.

"Prop 65 gets settled at the artwork stage, long before the container ships. Only units manufactured and labeled before January 1, 2028 can keep the old short form, so the packaging you approve in 2027 for 2028 production has to carry the new version, with a chemical named, if it uses a short-form warning at all."

Bernardo Campelo, Founder of PrepVia

Online Sales: The Product Page and the 60-Day Retailer Window

Under 25602(b)(1), an internet sale needs a warning with the required content, provided on the product display page, through a clearly marked hyperlink on that page using "WARNING", "CA WARNING" or "CALIFORNIA WARNING", or otherwise prominently displayed to the purchaser before the purchase is completed. OEHHA treats that online warning as a second one, not a substitute: its statement of reasons says that "for safe harbor protection, a business must provide a warning on or with the product," and that for internet sales "the business must also provide" one on the product page or before checkout. On that reading, an Amazon listing warning does not replace the warning on the unit.

Two lines in the same subsection settle most website questions. If the label carries the short form, "the warning provided on the website may use the same content." And "the warning is not prominently displayed if the purchaser must search for it in the general content of the website."

Retailers get a transition of their own. For "internet purchases made before January 1, 2028," 25602(b)(2) says a retail seller is not responsible under 25600.2(e)(4) for posting the new warning online "until 60 calendar days after the retailer receives a warning or a written notice" that replaces an old short form with the new content. The window does not reach purchases made from January 1, 2028. In our reading, it only pauses the duty that comes from receiving a supplier's notice, so it does not help a seller that sells under its own or a licensed brand, which answers under 25600.2(e)(1) on its own site or on Amazon.

Who the Rules Make Responsible

The statute sets the duty. Health and Safety Code section 25249.6 says: "No person in the course of doing business shall knowingly and intentionally expose any individual to a chemical known to the state to cause cancer or reproductive toxicity without first giving clear and reasonable warning to such individual, except as provided in Section 25249.10." Section 25249.11(f) then says the regulations shall, "to the extent practicable," "place the obligation to provide any warning materials such as labels on the producer or packager rather than on the retail seller," except where the retailer itself introduced the chemical.

The regulation names the parties. Under 27 CCR 25600.2(b), the manufacturer, producer, packager, importer, supplier or distributor can comply either with a warning on the product label or labeling, or with a written notice, renewed annually, to the authorized agent of the business it sells or transfers the product to.

Under the Article 6 definitions (OEHHA's 2017 text), a label is material "printed on or affixed to a product or its immediate container or wrapper," and a retail seller is a business that sells consumer products directly to consumers "by any means, including via the internet." The statute's definition of a person in the course of doing business "does not include any person employing fewer than 10 employees," but Amazon's Prop 65 help page tells sellers they are responsible for Prop 65 warnings "even if you have fewer than 10 employees, and even if someone else is selling the same product."

Relabeling and Kitting at a 3PL: Who Decides, Who Applies

A 3PL or prep center works on the seller's instructions. The regulation does not name 3PLs, and it does not define "packager," one of the parties it does name, so whether a 3PL that builds a kit box counts as a packager is a question for your counsel. Whether a product needs a warning and which chemical it names should be settled by the brand or seller and the parties the regulation names; the 3PL carries out the work order: where labels go, what stays visible and what the finished unit or kit shows the buyer.

Amazon's labeling rules point the same way. Its label placement requirements say to "Cover all other visible barcodes, except for any serial number barcodes or Transparency authentication code labels," and then: "Do not cover any other stickers or labels that have already been placed on the product, as these might contain relevant warning, safety or compliance information."

• Relabeling. In our reading, a new consumer label applied on or after January 1, 2028 that carries a short form needs the new content. If the new label would cover the manufacturer's warning, that is one of the cases in 25600.2(e)(3) that makes the seller responsible, so the warning should reappear on the new label.
• Kits. The definition of a label points to the product's immediate container, and for a kit that is likely the kit box. A component's warning sealed inside an opaque box may not be seen until the box is opened, and 25601(c) asks for a warning "likely to be seen, read, and understood" under customary conditions of purchase or use. In our reading, if the kit needs a warning, it belongs on the outside.
• Breaking master cartons. If the warning is printed only on an outer carton, units shipped one by one reach the buyer without it, and OEHHA expects a warning on or with each unit sold online.

The work order settles it: the brand or seller sends the exact warning text, the chemical named, the minimum type size and the placement for each SKU and kit, and the 3PL applies that file. The federal side of a kit is in our guide to kitting regulated products, and Amazon's bundle rules are in kitting vs bundling for FBA.

What OEHHA Has Floated, and What It Has Not Proposed

OEHHA held a pre-regulatory workshop on July 30, 2026 on a package it calls Omnibus 2026, and accepted comments until September 7, 2026, according to its workshop slides. The slides are plain about status: "Do not rely on these discussion drafts, which do not supersede existing laws and regulations."

Three of the eight topics touch this post. Topic 2, which OEHHA calls a technical fix, would change "[name of chemical]" to "[name of one or more chemicals]" in the "risk from exposure to" versions of the short form in the draft text, to make clear that a business may warn for more than one chemical. Topic 5 would write into the rule what OEHHA already reads into it, that internet sales need the warning in two places: "A warning must also be provided on or with the delivered product sold over the Internet." Topic 6 rewrites the retailer rule, which OEHHA says would clarify "that a warning must be given to consumers even if the retailer removes an item from its original packaging before sale or use," with a box of bulk items as the example.

It is not a formal proposal: the California Regulatory Notice Register, which the Office of Administrative Law publishes every Friday, carried no OEHHA notice on these sections in its issues from September 4 through October 23, 2026. A formal notice has to be published at least 45 calendar days before its comment period closes.

Where the Warning Goes on Amazon

Amazon's Prop 65 help page puts the job on the seller. For every existing and new listing, you must "Determine if the product needs a Prop 65 warning" and "Provide Amazon with the correct Prop 65 warning using the instructions on this page (and not in any other way, such as by email)."

In Seller Central, the warning goes in the listing's Compliance tab: select the California Proposition 65 Warning Type and, if needed, the California Proposition 65 Chemical Name(s). Bulk templates carry the same attributes in the Compliance group, listings built with custom feeds have to add them through one of those two routes, and warnings go on child SKUs, since a warning on a parent SKU fails.

What the page does not have, as of October 29, 2026, is any mention of the 2025 amendments or of January 1, 2028, or an "On Product" type for a short form that names a chemical; it still describes the regulations that took effect on August 30, 2018. If your new label carries the new short form, none of the three "On Product" types matches what is printed, so check the live page before you change the warning type on a listing.

The rule is less clear about listings for units manufactured and labeled before 2028 and sold after it. Section 25603(c) covers the warning on the product, and OEHHA's statement of reasons expects websites to be "updated with the new warning content by the time the three years expires." Ask counsel before January 1, 2028 whether those listings need a warning type that names a chemical, even while the units keep the old label.

Also read the Prop 65 clause in Amazon's Business Solutions Agreement. In section S-1.1, the seller agrees that Amazon's display of the warning on the detail page "is confirmation of our receipt of that warning," and that it "will only revise or remove a Proposition 65 Warning for a product when the prior warning is no longer legally required." Changing the warning type on a live ASIN reads as a revision, so treat it as its own decision, made with counsel, not a side effect of new packaging.

Where a Prep Center Fits

A prep center handles units when a new consumer label or kit box goes on, so the warning should be decided before the units arrive. The regulation names the manufacturer, producer, packager, importer, supplier or distributor, and on Amazon the seller decides whether a product needs a warning. A 3PL asked to apply a warning applies the brand's file as written and keeps FNSKU stickers off existing warning labels, as Amazon requires, and, as a precaution, off warnings printed on the package.

PrepVia's part is the physical work: kits, bundles and multipacks, FNSKU, barcode and suffocation-warning labels, and case packs, at 8507 NW 72nd St, Miami, FL 33166, with a prep window of 24-36 hours. The Prop 65 decision stays with the brand.

Frequently Asked Questions

Do units with the old short-form warning have to be relabeled in 2028?

Not because of the date. Under 27 CCR 25603(c), a product manufactured and labeled before January 1, 2028 may keep the old content "regardless of when the product is sold to a consumer," and OEHHA's statement of reasons says "no relabeling is required by the proposed amendments."

What does the new short-form warning have to include?

The warning symbol, a yellow triangle that may be printed in black and white when the label is not printed in yellow; "WARNING:", "CA WARNING:" or "CALIFORNIA WARNING:" in bold capital letters; and a sentence that names the chemical, such as "Cancer risk from exposure to [name of chemical]. See www.P65Warnings.ca.gov." It can never be smaller than 6-point type. Food and dietary supplements use the version in 25607.2(b), which points to www.P65Warnings.ca.gov/food.

Can a kit built in 2028 from units made in 2027 use the old short form?

The old content requires that the product be both manufactured and labeled before January 1, 2028. A kit label applied on or after that date does not meet the second condition, so in our reading a short-form warning on it needs the new content.

Is my 3PL responsible for the Prop 65 warning when it relabels my products?

The regulation does not name 3PLs, and it does not define "packager," one of the parties it does name. The brand or seller should decide the warning and send it to the 3PL in writing, and under Amazon's rules the FNSKU sticker must not cover existing warning labels.

Where do I enter a Prop 65 warning for an Amazon listing?

On the listing's Compliance tab in Seller Central, as the California Proposition 65 Warning Type and, if needed, the Chemical Name(s). In OEHHA's reading, the listing warning does not replace a warning on or with the unit. As of October 29, 2026, the "On Product" types on Amazon's help page still show only the old text, so check the live page before you change a listing.

Do online retailers get extra time to post the new warning?

For internet purchases made before January 1, 2028, a retail seller is not responsible for posting the new warning online until 60 calendar days after it receives the updated warning or a written notice from its supplier. The window does not cover purchases made from that date on, and in our reading it does not help a seller that sells under its own or a licensed brand.

Final Take

The 2028 date is a manufactured-and-labeled date, not a sale date. Units manufactured and labeled before January 1, 2028 can keep the old short form for as long as they sell, and any other short-form warning has to name a chemical. For brands, that puts the decision in the 2027 artwork cycle; for anyone putting a new consumer label or kit box on units at a 3PL, it puts it on the work order for every build from January 1, 2028.

The regulation does not name the 3PL and does not define "packager," so the warning is best decided before the build, by the brand or seller and the parties the regulation names. The 3PL applies it without covering what is already on the unit, and the Amazon listing warning should be checked against the unit before the build ships.