California Prop 65 Checker

This Prop 65 checker scans product names, ingredient lists, CAS numbers, and warning text against the California Proposition 65 list of chemicals so you can flag exposures and validate label wording before a listing goes live. It is built for retail and marketplace teams who enrich thousands of SKUs and need a fast, repeatable first-pass review.

What it checks

Paste a single product or a full export, and the checker evaluates each row for the signals that drive Prop 65 obligations:

• Listed-chemical matches — scans ingredient strings and CAS numbers against the Prop 65 chemical list, including common synonyms (for example, “DEHP” alongside “di(2-ethylhexyl)phthalate”).
• CAS number validity — confirms each CAS Registry Number passes its check-digit test before it is matched, so a typo in a furniture finish or industrial lubricant spec does not produce a false clear.
• Toxicity endpoint — flags whether a matched chemical is listed for cancer, for reproductive toxicity, or for both, since the warning wording differs.
• Warning-text structure — checks existing Prop 65 warning strings for the expected elements: the triangular symbol reference, the word “WARNING”, at least one named chemical, and a reference URL.
• Missing-warning flags — highlights rows that match a listed chemical but carry no warning text at all.
• Free-text noise — strips marketing copy and units so a CPG cleaning spray, an MRO solvent, or an upholstered chair is judged on its substances, not its adjectives.

How the Prop 65 checker works

California’s Proposition 65 (the Safe Drinking Water and Toxic Enforcement Act of 1986) requires a “clear and reasonable” warning before knowingly exposing people to chemicals on a state-maintained list of substances known to cause cancer or reproductive harm. Each entry on that list carries a chemical name and, where one exists, a CAS number — the same identifier validated by a CAS number validator.

The tool works in three stages. First it normalizes your input: ingredient strings are tokenized, CAS numbers are extracted and check-digit verified, and synonyms are folded to a canonical name. Then it matches each normalized token against the listed-chemical reference and records the toxicity endpoint. Finally, if a warning string is present, it parses that text for the structural elements a compliant short-form or long-form warning is expected to contain.

1. 1
   Paste or upload
   Drop in a product row, an ingredient deck, or a full CSV export from your PIM or marketplace feed.
2. 2
   Match and verify
   Each CAS number is check-digit validated, then matched against the listed-chemical reference with synonym folding.
3. 3
   Review flags
   See per-row results: listed chemical, endpoint, whether a warning is present, and whether its wording is well-formed.

All processing happens client-side in your browser. Nothing is uploaded, stored, or sent to a server, so confidential formulations and pre-launch catalogs never leave your machine. This makes the checker safe to run against an unredacted furniture-finishes sheet or an industrial-chemical price file.

A spot-check tool clears one batch. The harder problem is keeping a compliance attribute accurate across hundreds of thousands of SKUs as suppliers revise formulations — which is where a canonical data layer with source-linked enrichment earns its place. See how Claro grounds enrichment in source documents so a Prop 65 flag carries the evidence behind it.

Related resources

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