# 2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol

URL: https://app.greenveil.ai/ingredients/ingredient_cas_1444596_49_9
Categories: beauty
Functions: Hair dyeing
Identifier: 1444596-49-9

> 2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol: Used in cosmetics as a hair dye. Greenveil chemical-concern score: 70/100 — High concern based on regulatory listings.. Compiled from 3 published data sources.

## Safety assessment

- Chemical concern score: 70/100 — High concern based on regulatory listings.
- Confidence in this assessment: High
- Is it a concern? High concern: no hazard classifications on record. It is restricted in EU cosmetics.
- Rationale: 2-chloro-4-{(E)-[3-(methylthio)-1,2,4-thiadiazol-5-yl]diazenyl}phenol is restricted in cosmetic products under Annex III of the EU Cosmetics Regulation (EC) 1223/2009.

## Regulatory status

- EU: Active — Cosmetics Regulation annex III / ref 386.
- EU: Active — Listed in CosIng inventory for cosmetic use.
- EU: restricted — Annex III of EU Cosmetics Regulation (EC) 1223/2009: substances which cosmetic products must not contain except subject to the restrictions laid down. Product types: (a) Hair dye substance in oxidative hair dye products (b) Hair dye substance in non-oxidative hair dye products Maximum concentration: (b) 0,5 % Other conditions: For (a): After mixing under oxidative conditions the maximum concentration applied to hair must not exceed 1,5 %. Conditions of use and warnings: For (a): To be printed on the label: The mixing ratio. “Hair colourants can cause severe allergic reactions. Read and follow instructions. This product is not intended for use on persons under the age of 16. Temporary ‘black henna’ tattoos may increase your risk of allergy. Do not colour your hair if: — you have a rash on your face or sensitive, irritated and damaged scalp, — you have…

## 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/106938
- EU CosIng Cosmetics Regulation Annexes (updated 2026-05-06): https://ec.europa.eu/growth/tools-databases/cosing/reference/annexes/list/III
- 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

_Assessed by Greenveil._