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Annex II Entry 721 CMR21/10/2010

4,4'-Bi-o-toluidine (ortho-Tolidine)

4,4'-Bi-o-toluidine (ortho-Tolidine) is listed in Annex II as a prohibited substance for cosmetic products placed on the EU market.

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Prohibited substance— Annex II, EU Regulation 1223/2009
Entry: 721
CMR

Chemical identity and properties

PubChem 2D chemical structure for CAS 119-93-7
CAS 119-93-7PubChem CID 8413

o-Tolidine

3,3'-dimethylbenzidine appears as white to reddish crystals or crystalline powder or a light tan powder. (NTP, 1992) — CAMEO Chemicals

IUPAC name
4-(4-amino-3-methylphenyl)-2-methylaniline
Molecular formula
C14H16N2
Molecular weight
212.29 g/mol
Exact mass
212.131348519 Da
XLogP3
2.3
Topological polar surface area
52.0 Ų
Hydrogen-bond donors
2
Hydrogen-bond acceptors
2
Covalent units
1
Defined stereocentres
0

Also known as

3,3'-DIMETHYLBENZIDINEOrthotolidineDiaminoditolyl2-TolidineBianisidineDiaminotolyl4,4'-Bi-o-toluidine3,3'-Tolidine
16 more reported names
Fast Dark Blue Base R3,3'-Dimethyl-4,4'-biphenyldiamine3,3'-Dimethyl-4,4'-diaminobiphenyl4,4'-Diamino-3,3'-dimethylbiphenyl2-Tolidina2-Tolidin4,4'-Di-o-toluidineRCRA waste number U0953,3'-Dimethylbiphenyl-4,4'-diamine[1,1'-Biphenyl]-4,4'-diamine, 3,3'-dimethyl-o-Tolidin3,3'-dimethyl-[1,1'-biphenyl]-4,4'-diamineTolidine, o-C.I. 37230C.I. Azoic Diazo Component 113CCRIS 256
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Evidence from additional scientific databases

NIH PubChem PUG-View
Exact identifier match8413

Attributed physical-property, hazard, environmental and use annotations.

  • First Aid: EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.; SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. IMMEDIATELY call a hospital or poison control center even if no symptoms (such as redness or irritation) develop. IMMEDIATELY transport the victim to a hospital for treatment after washing the affected areas.; INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknow Source: CAMEO Chemicals
  • First Aid: (General first aid procedures); Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.; Skin: Soap flush immediately - If this chemical contacts the skin, immediately flush the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water. If irritation persists after washing, get medical attention.; Breathing: Respiratory support; Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately. Source: The National Institute for Occupational Safety and Health (NIOSH)
  • Signal: Danger Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • GHS Hazard Statements: H302: Harmful if swallowed [Warning Acute toxicity, oral]; H350: May cause cancer [Danger Carcinogenicity]; H411: Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard] Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • Precautionary Statement Codes: P203, P264, P270, P273, P280, P301+P317, P318, P330, P391, P405, and P501 (click each P-code to see the statement) Source: Regulation (EC) No 1272/2008 of the European Parliament and of the Council
  • Signal: Danger Source: European Chemicals Agency (ECHA)
  • GHS Hazard Statements: H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]; H350 (100%): May cause cancer [Danger Carcinogenicity]; H411 (100%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard] Source: European Chemicals Agency (ECHA)
  • Precautionary Statement Codes: P203, P264, P270, P273, P280, P301+P317, P318, P330, P391, P405, and P501 (click each P-code to see the statement) Source: European Chemicals Agency (ECHA)
  • ECHA C&L Notifications Summary: Aggregated GHS information provided per 53 reports by companies from 4 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
  • Signal: Danger Source: NITE-CMC
  • GHS Hazard Statements: H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]; H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure] Source: NITE-CMC
  • Precautionary Statement Codes: P260, P264, P270, P319, and P501 (click each P-code to see the statement) Source: NITE-CMC
  • GHS Hazard Statements: H302: Harmful if swallowed [Warning Acute toxicity, oral]; H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity]; H350: May cause cancer [Danger Carcinogenicity]; H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]; H401: Toxic to aquatic life [Hazardous to the aquatic environment, acute hazard]; H411: Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard] Source: NITE-CMC
  • Precautionary Statement Codes: P203, P260, P264, P270, P273, P280, P301+P317, P318, P319, P330, P391, P405, and P501 (click each P-code to see the statement) Source: NITE-CMC
  • Environmental Bioconcentration: Using carp (Cyprinus carpio) which were exposed over an 8-week period in a continuous flow system and 3,3'-dimethylbenzidine concentrations of 0.02 and 0.2 mg/L, a 3,3'-dimethylbenzidine BCF range of 4.8 to 83 was measured(1). According to a classification scheme(2), these BCF values suggest bioconcentration in aquatic organisms is low to moderate(SRC). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 3190(SRC), determined from a structure estimation method(2), indicates that 3,3'-dimethylbenzidine is expected to have slight mobility in soil(SRC). The pKa values of 3,3'-dimethylbenzidine are 4.50 and 3.3(3), indicating that this compound will exist partially in the cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). In sediment studies, sorption measurements over the pH range of 5 to 9 saw an increase in sorption as the pH decreased suggesting that the protonated form of 3,3'-dimethylbenzidine was more strongly bound than the neutral form(5). Volatilization of 3,3'-dimethylbenzidine from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 6.3X10-11 atm-cu m/mole(SRC), using a fragment constant estimation method(2). 3,3'-Dimethylbenzidine is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 1.0X10-6 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). 3,3'-Dimethylbenzidine, p Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 3190(SRC), determined from a structure estimation method(2), indicates that 3,3'-dimethylbenzidine is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 6.3X10-11 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). According to a classification scheme(7), BCF values in the range of 4.8 to 83(4), measured in carp (Cyprinus carpio), suggest bioconcentration in aquatic organisms is low to moderate(SRC). 3,3'-Dimethylbenzidine, present at 100 mg/L, reached 3% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L and the Japanese MITI test(6), indicating the compound is not readily biodegradable(5). 3,3'-Dimethylbenzidine absorbs light >290 nm(6) and may be susceptible to direct photolysis. When aerated solutions of benzidine were exposed to a light from a xenon lamp (300-400 nm) complete degradation of benzidine was observed in 12 hours(7); photodegradation of 3,3'-dimethylbenzidine may be similar(SRC). Aromatic amines are susceptible to photooxidation Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 3,3'-dimethylbenzidine, which has an estimated vapor pressure of 1.0X10-6 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase 3,3'-dimethylbenzidine is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 2 hours(SRC), calculated from its rate constant of 1.9X10-10 cu cm/molecule-sec at 25 °C (SRC)determined using a structure estimation method(2). 3,3'-Dimethylbenzidine absorbs light >290 nm(3), therefore, it may be susceptible to direct photolysis(SRC). Particulate-phase 3,3'-dimethylbenzidine may be removed from the air by wet and dry deposition(SRC). Source: Hazardous Substances Data Bank (HSDB)

Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record

Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.

Additional source coverage and match status
SourceResultChecked
NIH PubChem PUG-ViewExact match2026-08-31

A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Chemical name

4,4'-Bi-o-toluidine (ortho-Tolidine)

Chemical / IUPAC name

o-Tolidine

Regulatory information

Regulation

(EC) 2009/1223

See every entry this act set

SCCS opinions

CMR

CategoryCarcinogenicMutagenicReprotoxic
Cat. 1B✓——

Key data

CAS
119-93-7
EC
204-358-0
Annex
II
Entry number
721

Direct matches are limited for this record, so nearby entries from Annex II are shown as well.

Annex II 727
Nearby record in the same annex

Azobenzene

CAS: 103-33-3
EC: 203-102-5

What Annex II means for 4,4'-Bi-o-toluidine (ortho-Tolidine)

4,4'-Bi-o-toluidine (ortho-Tolidine) is listed as a prohibited substance under Annex II of EU Cosmetics Regulation 1223/2009 and must not be intentionally added. Article 17 separately addresses unintended small quantities that are technically unavoidable under good manufacturing practice and compatible with the Article 3 safety requirement.

Formulators must screen their ingredients and raw materials to ensure none contain this substance. Suppliers should provide documentation confirming absence when requested.

The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.

Compliance checklist

  • Verify this substance is absent from all raw materials and finished formulations.
  • Request absence confirmation or CoA from raw material suppliers.
  • Document the screening result in the Product Information File (PIF).
  • This substance has CMR classification. Review the CMR table above and verify current Annex II/III status before use.

Frequently asked questions

Yes. 4,4'-Bi-o-toluidine (ortho-Tolidine) is listed in Annex II of EU Cosmetics Regulation 1223/2009 and is prohibited as an intentionally added cosmetic ingredient. Article 17 provides a narrow exception for unintended small quantities that are technically unavoidable under good manufacturing practice, provided the product remains safe under Article 3.

CAS 119-93-7 is the unique numerical identifier assigned to 4,4'-Bi-o-toluidine (ortho-Tolidine) by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

4,4'-Bi-o-toluidine (ortho-Tolidine) has a CMR (carcinogenic, mutagenic or reprotoxic) classification under EU CLP Regulation. Under Article 15 of EU Cosmetics Regulation 1223/2009, CMR substances of category 1A or 1B are prohibited in cosmetics unless specifically permitted. Category 2 CMR substances may be used only if assessed safe by the SCCS. Always verify current annex status and any applicable derogations before use.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex II record 4,4'-Bi-o-toluidine (ortho-Tolidine)

This page summarizes one Annex II record for 4,4'-Bi-o-toluidine (ortho-Tolidine) from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.

Use this record page to review Annex II conditions for 4,4'-Bi-o-toluidine (ortho-Tolidine), but confirm any final regulatory decision against the current official annex wording and source files.

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