Prop 65 Lookup
Free tool
Enter one substance — name or CAS number — and see whether it appears on the California Proposition 65 list, checked against a dated copy of OEHHA's published list.
Listing is not the obligation. A Proposition 65 warning turns on exposure, not on list membership. OEHHA publishes safe-harbor levels — No Significant Risk Levels (NSRLs) for cancer endpoints and Maximum Allowable Dose Levels (MADLs) for reproductive endpoints — and a warning is not required for an exposure at or below the safe-harbor level established for a chemical. Not every listed chemical has a safe-harbor level.
Failure to provide a required warning can carry civil penalties under California Health & Safety Code §25249.7. This tool reports list membership only — it does not calculate exposure, apply a safe-harbor level, or tell you whether a warning is required.
For the Proposition 65 programme generally see OEHHA — Proposition 65, and the list itself at OEHHA — The Proposition 65 List.
These results are list-membership facts as of the dated copy of each list identified on the result. Absence from these lists is not evidence of safety or of regulatory non-applicability. Safety Data Sheets and the primary source lists remain authoritative.
California Prop 65 data: OEHHA, The Proposition 65 List.
Data as of: California Proposition 65 2026-07-31 — OEHHA Proposition 65 list dated 2026-07-31.
Reference only. Not legal or regulatory advice. Verify against the primary source before you act.
How it works
This tool screens a single substance — by name or by CAS number — against a dated copy of the California Proposition 65 list published by the Office of Environmental Health Hazard Assessment (OEHHA). The copy used here is OEHHA Proposition 65 list dated 2026-07-31. It screens that list and nothing else: no other jurisdiction, no other list.
Matching is exact, never fuzzy. A CAS number matches only an identical CAS token, and a name matches only a known entry name or a curated synonym of one. Some OEHHA rows carry several CAS numbers for one chemical; a query matches if it equals any of them.
Four verdicts are distinct and are never collapsed into each other:
- Listed— the substance's own CAS number appears on a current listing. The entry's toxicity type, listing mechanism and date listed are shown.
- Qualified match — your input equals a reference form of one or more OEHHA entries rather than an entry itself (for example Nickel, which OEHHA lists as two separate entries). The tool shows every matching entry's full verbatim OEHHA name so you can decide whether your substance is the listed form. A qualified match is never presented as "Listed".
- Formerly listed — OEHHA removed the chemical from the list. This is shown with the delisting date and is never rendered as listed.
- Not found — the substance is absent from this dated copy. That is a fact about one list on one date, not a safety conclusion.
The result states exactly which dated copy of the list was used and links the official OEHHA source. The list changes — OEHHA is always authoritative.
- A pill is an exact, current, identifier-level match
- A status pill next to a substance means one thing: that list has a current entry reached by an unambiguous identifier match. Every other state renders nothing at all. Silence on a pill is never a claim that a substance is absent from a list, and it is never a clean bill of health — it means the pill's own test was not met, which includes several kinds of real hit that a four-character label cannot qualify.
- Group listings
- A substance can be covered by a list without appearing on it by name, as a member of a listed group entry. The tools report that as a group listing and name the group entry so it can be checked. The source list itself carries no identifier for the group entry, so the membership comes from this site's curated group-alias table rather than from the publisher — which is why it is reported as something to review rather than as a match.
- Salts, esters and the parent compound
- Lists frequently name a parent compound, a salt of it, or a defined family, each under its own identifier. A query that reaches a related entry rather than the queried substance itself is reported as a qualified match, with the related entries named: the tool tells you what it found and stops, because whether your material is the listed form is a reading of the entry, not a lookup.
- Delisting
- A list can carry an entry for a substance that is no longer listed. Those entries are present in the committed data and are reported as formerly listed, with the date, never as a current listing and never as a plain absence. A substance can also hold both a delisted entry and a separate current one, in which case it is currently listed — the answer is about the substance, not about a row.
- CEPA Schedule 1 is matched by name
- Schedule 1 to the Canadian Environmental Protection Act, 1999 identifies substances by name, description and molecular formula. No entry on it carries a CAS number, so matching against it is name-level and requires review. A separate CAS mapping published by Environment and Climate Change Canada is used where it helps, and it is explicitly non-exhaustive: a substance the mapping does not reach is reported as having no CAS association, never as absent from the schedule.
- What "Review" means
- Review is not an error and it is not a maybe. It marks a result that is a real hit of a kind a one-word verdict would misreport: a formerly listed entry, a qualified match against a related form, a name-level match, or a group listing. Each of those needs a person to read the entry and decide whether it describes their material. A cell marked Review has more information behind it, not less.
Worked example
Searching Nickel returns a Qualified match, not "Listed". OEHHA has no entry called simply "Nickel" — it carries Nickel (Metallic) (cancer, listed 1989-10-01) and Nickel (soluble compounds) (developmental, male; listed 2018-10-26). Both are shown verbatim so you can identify which form you actually have.
Searching Quartz, Crystalline silica or 14808-60-7 all reach the same qualified match against Silica, crystalline (airborne particles of respirable size) — the synonym bridge resolves the identity, and the qualified tier then fires on the entity, not just on the exact string you typed.
Searching 107-05-1 (Allyl chloride) returns Formerly listed — OEHHA delisted it on October 29, 1999 — never "Listed".
Searching 1163-19-5 (decabromodiphenyl ether) returns Not found on this dated copy. The same substance is on the EU REACH SVHC Candidate List — absence here says nothing about any other list.
Sources · OEHHA
Sources
The Proposition 65 List
California Office of Environmental Health Hazard Assessment (OEHHA), OEHHA Proposition 65 list dated 2026-07-31
California Health and Safety Code §25249.5 et seq.
California Prop 65 data: OEHHA, The Proposition 65 List.
open the source
Data vintage
- Data: California Proposition 65 list, California Office of Environmental Health Hazard Assessment (OEHHA) list dated 2026-07-31 (stated in the file header), retrieved 2026-08-01, 990 rows.990 rows = 965 active and 25 delisted. OEHHA ships delisted chemicals inline in the same sheet; 111 entries carry no CAS number and match by name only.
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last updated 2026-08-04