Is O-Aminophenol safe in cosmetics?
O-Aminophenol has a safety rating of "POOR" in our database. EU status: restricted. US status: permitted. 10 toxicological study endpoint(s) are available in our database.
O-Aminophenol
Also known as: CI Oxidation Base 17, EINECS 202-431-1, 2-Hydroxyanaline, Nako Yellow ga, Questiomycin B (+1 more)
INCI: O-AMINOPHENOL
O-Aminophenol (CAS 95-55-6) is a cosmetic cosmetic ingredient functioning as Hair dye (oxidative). NOAEL 5 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: restricted, max 2.0%. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in pharmaceutical data.
View industrial chemical safety profile for CAS 95-55-6 →
Auto-generated CPSR Part A draft with source citations
Function
Hair dye (oxidative)
Safety Rating
POOR
Chemistry & Identifiers
IUPAC Name
2-aminophenol
InChIKey
CDAWCLOXVUBKRW-UHFFFAOYSA-N
Regulatory Status
EU EU Status
restricted
EU Max Conc.
2.0%
US US Status
permitted
US Notes
Permitted under coal-tar hair dye exemption (FD&C Act §601(a)); requires caution statement and patch-test directive on label
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for O-Aminophenol.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for O-Aminophenol. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
| Endpoint | Value | Route | Species | Study Type | Source |
|---|---|---|---|---|---|
| NOAEL | =1.7 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =1.7 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =1.7 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =1.7 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =5 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =5 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =5 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =5 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =15 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
| NOAEL | =15 mg/kg bw/d | oral | rat | repeated dose toxicity | SCCS_vision_codex |
GHS Hazard Classification
Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.
Short-term Exposure Effects
The substance may cause effects on the blood. This may result in the formation of methaemoglobin. The effects may be delayed. Medical observation is indicated.
Long-term Exposure Effects
Repeated or prolonged contact may cause skin sensitization.
Routes of Exposure
The substance can be absorbed into the body by ingestion, through the skin and by inhalation of its aerosol.
Pre-Calculated Safety Assessment
Pre-calculated NOAEL → SED → MoS audit trail for O-Aminophenol across SCCS product categories, with measured dermal absorption where available.
Sensitization Profile
Contact sensitization data for O-Aminophenol based on clinical patch test studies and IFRA standards.
Sensitization Rate
low
Allergen Class
dye
EU Allergen Listed
no
Patch Test Positive Rate
0.3%
Cross-reactivity Group
para-amino-group
Reaction Type
contact-dermatitis
Source: IVDK; NACDG; ESSCA
EU CLP Annex VI Harmonized Classification
Legally binding harmonized classification per Regulation (EC) No 1272/2008 (CLP) Annex VI.
Signal Word
Warning
Pictograms
Health HazardHarmful / Irritant
Hazard Class and Category
Muta. 2; Acute Tox. 4 *; Acute Tox. 4 *
Hazard Statements
- H341 Suspected of causing genetic defects
- H332 Harmful if inhaled
- H302 Harmful if swallowed
Inserted via ATP: CLP00
Sensitization AOP Dashboard
Adverse Outcome Pathway data across 5 assays (DPRA, KeratinoSens, hCLAT, LLNA, NESIL) aggregated from public sources.
DPRA Cys %
96.2%
DPRA Lys %
18.1%
KeratinoSens IC50
116.49 µM
hCLAT CV75
6 µg/mL
LLNA EC3
0.45%
NESIL
112.5 µg/cm²
LLNA: Strong (1A)
GHS: 1A
Source: LLNA: Gerberick et al. (2007) | Gerberick et al. (2005); DPRA: Natsch et al. 2013 [DOI:10.1002/jat.2868]; KS: Natsch et al. 2013 [DOI:10.1002/jat.2868] | Joint Research Centre of the European Union 2014; hCLAT: Nukada et al. 2011 [DOI:10.1111/j.1600-0536.2011.01952.x]
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Intermediate
Tonnage Band
Intermediate use only
Substance Type
SUBSTANCE
SVHC Candidate
No
Hazard classification: Restricted (Annex XVII)
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
JPKR Japan/Korea Cosmetics
Korea (Prohibited): Genotoxic, banned 2022; Category: General
Additional Jurisdictional Restrictions (4)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| CN | permitted_hair_dye | 1.5 | Oxidative hair dye products |
| IN | restricted | 1.5 | oxidative hair dye products |
| BR | permitted_hair_dye | - | Oxidative hair dye |
| KR | prohibited | - | - |
Additional Ingredient Properties
1 property record from structured ingredient metadata.
allergen_detail
{"eu_allergen_listed": "no", "allergen_class": "dye", "cross_reactivity_group": "para-amino-group", "patch_test_frequency_pct": "0.3", "sensitization_rate": "low", "common_reaction_type": "contact-dermatitis", "ifra_restricted": "no", "source": "IVDK; NACDG; ESSCA"}
PubChem Annotations
Safety and regulatory annotations from PubChem (NCBI) aggregated sources.
Safety (3)
Carcinogen Classification
No indication of carcinogenicity to humans (not listed by IARC).
Source: Toxin and Toxin Target Database (T3DB)
ICSC Safety Card
0824
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Skin Eye Respiratory Irritation
May cause eye irritation. May cause skin irritation. May cause respiratory tract irritation.
Source: Hazardous Substances Data Bank (HSDB)
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Dye
Expert Verdict
Expert safety assessment and concern-level summary for O-Aminophenol.
Regulatory Flags
potential-allergen
endocrine_disruptor
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to O-Aminophenol by CAS number or substance name.
Studies
21
Lowest NOAEL
1.7
Highest NOAEL
250
Units vary across source rows: mg/kg bw/day, mg/kg bw/d, mg/kg
ToxValDB_ECHA_IUCLID
SCCS_vision_codex
Known Synonyms
CI Oxidation Base 17
EINECS 202-431-1
2-Hydroxyanaline
Nako Yellow ga
Questiomycin B
UNII-23RH73DZ65
Chemical Function
Dye
Regulatory Lists
Canada; pharmaceutical
detected; Europe; Personal care - hair coloring - hair color - professional
detected; Europe; Personal care - hair coloring - hair color - professional
detected; Europe; Personal care - hair coloring - hair color - professional
detected; Europe; Personal care - hair coloring
detected; Europe; Personal care - hair coloring
Danish Environmental Protection Agency
Danish Environmental Protection Agency
Danish Environmental Protection Agency
Danish Environmental Protection Agency
Europe; Personal care - hair coloring
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
Compound
QUESTIOMYCIN B
ChEMBL ID
CHEMBL28319
Frequently Asked Questions
Is O-Aminophenol allowed in the EU?
O-Aminophenol EU regulatory status: restricted. Maximum allowed concentration: 2.0%. This is based on EU Regulation 1223/2009 and its amendments.
What does O-Aminophenol do in cosmetics?
O-Aminophenol functions as: Hair dye (oxidative). It is classified as a cosmetic ingredient in our database. CAS number: 95-55-6.
What is the NOAEL for O-Aminophenol?
The NOAEL (No Observed Adverse Effect Level) for O-Aminophenol is =1.7 mg/kg bw/d based on a repeated dose toxicity study via oral route in rat. A total of 10 study endpoints are available. Source: SCCS_vision_codex.
Is O-Aminophenol used outside cosmetics?
O-Aminophenol also appears in pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Compliance Tools
Check O-Aminophenol compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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