# Difethialone

URL: https://app.greenveil.ai/ingredients/ingredient_cas_104653_34_1
Categories: beauty, industrial
Identifier: 104653-34-1

> Difethialone. Greenveil chemical-concern score: 100/100 — Critical concern driven by cmr.. Compiled from 7 published data sources.

## Safety assessment

- Chemical concern score: 100/100 — Critical concern driven by cmr.
- Confidence in this assessment: High
- Is it a concern? Critical concern: classified for carcinogenic, mutagenic or reproductive toxicity (CMR). It is banned in EU cosmetics.
- Rationale: Difethialone (ISO); 3-[3-(4′-bromobiphenyl-4-yl)-1,2,3,4-tetrahydronaphthalen-1-yl]- 4-hydroxy-2H-1-benzothiopyran-2-one is prohibited in cosmetic products under Annex II of the EU Cosmetics Regulation (EC) 1223/2009.

## Regulatory status

- EU: Active — Cosmetics Regulation annex II / ref 1635.
- EU: banned — Annex II of EU Cosmetics Regulation (EC) 1223/2009: substances prohibited in cosmetic products. CMR: Reprotoxic Cat. 1B()
- US: commercial use observed — EPA CPDat observed this chemical in 0 composition records across product categories including unclassified products.
- US: listed in openFDA substance — openFDA substance registry classifies this ingredient as mixture.

## Expert safety opinions

- SCCS (EU Scientific Committee on Consumer Safety): no opinion on file.
- CIR (Cosmetic Ingredient Review (US expert panel)): no opinion on file.

## Data sources

- CosIng (updated 2026-09-23): https://ec.europa.eu/growth/tools-databases/cosing/details/98557
- EU CosIng Cosmetics Regulation Annexes (updated 2020-08-03): https://ec.europa.eu/growth/tools-databases/cosing/reference/annexes/list/II
- EPA Chemical and Products Database (updated 4 December 2007): https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A32007R1451
- EPA DSSTox Identifiers (updated 2025-12-29): https://epa.figshare.com/articles/dataset/Chemistry_Dashboard_Data_DSSTox_Identifiers_Mapped_to_CAS_Numbers_and_Names/5588566
- FDA GSRS UNII (updated 2026-02-26): https://precision.fda.gov/uniisearch/
- openFDA Substance (updated 2026-05-24): https://api.fda.gov/other/substance.json?search=unii:KOL4VXI5O0
- PubChem Live Enrichment (updated 2026-05-17): https://pubchem.ncbi.nlm.nih.gov/compound/91771

_Assessed by Greenveil._