- beauty
- industrial
3(or5)-[[4-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-1-naphthyl]azo]salicylic acid and its salts, when used as a substance in hair dye products
CAS 3442-21-5 · 100/100 · High conf.
Also registered as 1 other CAS number
34977-63-4
Concern score
100/100Critical concern based on regulatory listings.
High confidence
3(or5)-[[4-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-1-naphthyl]azo]salicylic acid and its salts, when used as a substance in hair dye products in plain language
On cosmetic ingredient lists it appears as “Direct black 51”.
Also known as Direct black 51 · Direct black 51, 5-SALICYLATE-
Used in cosmetics as a hair dye.
- Hair dyeing
- Colourant
- Critical concern: no hazard classifications on record. It is banned in EU cosmetics.
Why it's flagged
3(or5)-[[4-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-1-naphthyl]azo]salicylic acid and its salts, when used as a substance in hair dye products is prohibited in cosmetic products under Annex II of the EU Cosmetics Regulation (EC) 1223/2009.
RestrictedEU EC — banned
The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.
Regulation
Restrictions first, then routine listings from published regulatory sources.
- EU Annex II — prohibited
- EU prohibited in cosmetics
- Found in consumer products
- Industrial
- View source →banned
EUEC
Annex II of EU Cosmetics Regulation (EC) 1223/2009: substances prohibited in cosmetic products.
USEPAcommercial use observedEPA CPDat observed this chemical in 0 composition records across product categories including unclassified products. EPA CPDat classifies this chemical for functional uses including Dye.
- EPA CPDat observed this chemical in 0 composition records across product categories including unclassified products. EPA CPDat classifies this chemical for functional uses including Dye.Source →
USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
- openFDA substance registry classifies this ingredient as chemical.Source →
Expert safety opinions
No expert opinion on file for 3(or5)-[[4-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-1-naphthyl]azo]salicylic acid and its salts, when used as a substance in hair dye products. These are the independent scientific bodies that assess ingredients like this one; we show an opinion only when a record we hold cites it.
SCCS
EU Scientific Committee on Consumer Safety
No SCCS opinion on file.
CIR
Cosmetic Ingredient Review (US expert panel)
No CIR safety assessment on file.
Evidence & sources
No graded research studies for 3(or5)-[[4-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-1-naphthyl]azo]salicylic acid and its salts, when used as a substance in hair dye products yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.
Where this comes from
- Open →
CosIng
regulatory · updated 2026-09-23
- Open →
EU CosIng Cosmetics Regulation Annexes
regulatory · updated 2010-10-15
- Open →
EPA Chemical and Products Database
exposure · updated 2020-02-13
- Open →
EPA DSSTox Identifiers
chemistry · updated 2025-12-29
- Open →
FDA GSRS UNII
registry · updated 2026-02-26
- Open →
openFDA Substance
registry · updated 2026-05-24
Reference links (1)
Suitability
Context-specific fit derived from published classifications and the current ingredient evidence profile.
Fragrance avoidance
No fragrance-linked caution surfaced in the current profile.
This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.
Where it has been recorded
How often EPA CPDat has listed 3(or5)-[[4-[(7-amino-1-hydroxy-3-sulphonato-2-naphthyl)azo]-1-naphthyl]azo]salicylic acid and its salts, when used as a substance in hair dye products in a product composition. These are source records, not Greenveil catalog products.
Named organisations
1
Typical roles
Hair dyeingColourant