Colorant

Basic Orange 31

INCI: BASIC ORANGE 31
CAS 97404-02-9 EC 306-764-4
2-((4-Aminophenyl)azo)-1,3-dimethyl-1H-imidazolium chloride
Limited Data
Insufficient safety data available. Consider enriching this ingredient.
Details

Description

2-((4-Aminophenyl)azo)-1,3-dimethyl-1H-imidazolium chloride

Purpose

Function

Hair Dyeing (semi-permanent / direct dye)
Profile

Properties

Silicone
Silicone free
Compliance

Regulatory Status

EU
Banned
Safety
POOR
US
Restricted
Absorptionmoderate
Sensitizationmoderate
MoSnot established
NOAEL60 mg/kg
ConcernModerate
Flags
eu_children_restrictedeu_cosing_listed
Verdict

Contains primary aromatic amine (aminophenyl group) requiring monitoring for free amine levels; restricted to non-oxidative systems only; must comply with purity specifications

US Note

Not an approved color additive; usable under coal-tar hair dye exemption with caution statement

Assessment

Ratings

Comedogenic0/5
LowHigh
Irritancy0/5
LowHigh
Reference

Identifiers

CAS Number
97404-02-9
EC Number
306-764-4
INCI
BASIC ORANGE 31
Category
Colorant
Updated
Apr 2, 2026