Substance profile
O-Toluidine
O-Toluidine is a light yellow liquid becoming reddish brown on exposure to air and light with an aromatic aniline-like odor.
01 · Identification
What O-Toluidine is
O-Toluidine is a light yellow liquid becoming reddish brown on exposure to air and light with an aromatic aniline-like odor. Its molecular formula is C7H9N and its molecular weight is 107.15 g/mol. It boils at 200 °C, melts at -14.4 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
O-Toluidine identifiers and molecular data
O-Toluidine CAS number and EC number
O-Toluidine molecular formula and molecular weight
Other names for O-Toluidine
- 2-aminotoluene
03 · GHS classification
O-Toluidine hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
O-Toluidine pictograms and signal word
O-Toluidine hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - oral GHS chapter 3.1 | Category 3 | H301 | GHS06 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 3 | H331 | GHS06 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 2A | H319 | GHS07 |
| Carcinogenicity GHS chapter 3.6 | Category 1A or 1B | H350 | GHS08 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
O-Toluidine hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H350 | May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H331 | Toxic if inhaled. |
| H301 | Toxic if swallowed. |
| H319 | Causes serious eye irritation. |
| H400 | Very toxic to aquatic life. |
This page lists only the codes assigned to O-Toluidine. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for O-Toluidine
A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of O-Toluidine issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.
04 · Precautionary statements
O-Toluidine precautionary statements
CLP Annex VI assigns 18 precautionary statements to O-Toluidine. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Response
What to do once exposure, spillage or fire has already happened.
Disposal
What has to happen to the contents and the empty container.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
O-Toluidine name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | o -толуидин 2-аминотолуен |
| Spanish español | o -Toluidina 2-aminotolueno |
| Czech čeština | o -toluidin 2-methylanilin |
| Danish dansk | o -toluidin 2-aminotoluen |
| German Deutsch | o-Toluidin 2-Aminotoluol2-Methylanilin |
| Estonian eesti | o -toluidiin 2-aminotolueen |
| Greek ελληνικά | o -τολουιδίνη 2-αμινοτολουόλιο |
| English English | o -toluidine 2-aminotoluene |
| French français | o -toluidine 2-aminotoluène |
| Croatian hrvatski | o -toluidin 2-aminotoluen |
| Italian italiano | o -toluidina 2-aminotoluene |
| Latvian latviešu | o -toluidīns 2-aminotoluols |
| Lithuanian lietuvių | o -toluidinas 2-aminotoluenas |
| Hungarian magyar | o -toluidin 2-aminotoluol |
| Maltese Malti | o -toluidina 2-amminotoluwen |
| Dutch Nederlands | o -toluïdine 2-aminotolueen |
| Polish polski | o -toluidyna 2-toliloaminao -aminotolueno -metyloanilina |
| Portuguese português | o -toluidina 2-aminotolueno |
| Romanian română | o -toluidină 2-aminotoluen |
| Slovak slovenčina | orto -toluidín 2-metylanilín |
| Slovenian slovenščina | o -toluidin 2-aminotoluen |
| Finnish suomi | o -toluidiini 2-aminotolueeni |
| Swedish svenska | o -toluidin 2-aminotoluen |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
O-Toluidine GHS label elements
Everything CLP Annex VI fixes for O-Toluidine, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
O-Toluidine
- May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- Toxic if inhaled.
- Toxic if swallowed.
- Causes serious eye irritation.
- Very toxic to aquatic life.
- Obtain special instructions before use.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Wash … thoroughly after handling.
- Do not eat, drink or smoke when using this product.
- Use only outdoors or in a well-ventilated area.
- Avoid release to the environment.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF INHALED:
- IF IN EYES:
- IF exposed or concerned:
- Immediately call a POISON CENTER/doctor/…
- Get medical advice/attention.
- Rinse mouth.
- If eye irritation persists:
- Remove contact lenses, if present and easy to do. Continue rinsing.
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open O-Toluidine in the GHS label constructor →
07 · Health hazards
O-Toluidine health hazards and exposure limits
O-Toluidine hazard summary
o-Toluidine is primarily used in the manufacture of dyes. o-Toluidine is highly toxic to humans when absorbed through the skin, inhaled as vapor, or swallowed. Acute (short-term) exposure of humans to o- toluidine affects the blood (i.e., methemoglobinemia), with clinical signs of central nervous system depression. The chronic (long-term) effects in workers exposed to o-toluidine include anemia, anorexia, weight loss, skin lesions, central nervous system depression, cyanosis, and methemoglobinemia. Animal studies indicate that chronic exposure too-toluidine causes effects on the spleen, liver, urinary bladder, and blood. Occupational exposure to dyestuffs (including o-toluidine) is associated with an increased risk of bladder cancer. 2-Methylaniline hydrochloride (the hydrochloride salt of o-toluidine) was carcinogenic in rats and mice. o-Toluidine has been classified by EPA as a Group B2, probable human carcinogen.
Source: EPA Hazardous Air Pollutants
O-Toluidine carcinogenicity classification
There is sufficient evidence in humans for the carcinogenicity of ortho-toluidine. There is sufficient evidence in experimental animals for the carcinogenicity of ortho-toluidine. Overall evaluation ortho-Toluidine is carcinogenic to humans (Group 1).
Source: Hazardous Substances Data Bank (HSDB)
o-Toluidine: reasonably anticipated to be human carcinogens. /o-Toluidine and o-Toluidine Hydrochloride/
Source: Hazardous Substances Data Bank (HSDB)
An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.
O-Toluidine occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 5.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 5 ppm (22 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 5 ppm (22 mg/m3) [skin] | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | Ca [skin] See Appendix A | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 50 ppm ; A potential occupational carcinogen. (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 50.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | NIOSH considers o-toluidine to be a potential occupational carcinogen. | Hazardous Substances Data Bank (HSDB) |
These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.
08 · Physical and chemical properties
O-Toluidine properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
O-Toluidine boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 200.3 °C (392.5 °F) | HSDB | |
| 200 °C (392 °F) | NIOSH |
O-Toluidine melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -14.41 °C (6.1 °F) | HSDB | |
| -23.7 °C (-10.7 °F) | alpha form | HSDB | |
| -14.44 °C (6 °F) | NIOSH |
O-Toluidine density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.01 g/cm³ | NIOSH | |
| 0.9984 g/cm³ | at 20 °C | HSDB | |
| 0.998 g/cm³ | at 20 °C | CAMEO |
O-Toluidine solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in alcohol and ether | HSDB | |
| Miscible in ethanol, diethyl ether, carbon tetrachloride | HSDB | ||
| Soluble in dilute acids | HSDB |
O-Toluidine vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.3 mmHg | NIOSH | |
| 0.1 mmHg | at 20 °C | CAMEO | |
| 0.26 mmHg | at 25 °C | HSDB |
O-Toluidine flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 85 °C (185 °F) | HSDB |
O-Toluidine autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 482.22 °C (900 °F) | HSDB | |
| 480 °C (896 °F) | ICSC |
O-Toluidine lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 1.5 % by volume | HSDB |
O-Toluidine upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 7.5 % by volume | HSDB |
O-Toluidine vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 3.69 (air = 1) | HSDB | |
| 3.7 (air = 1) | ICSC |
O-Toluidine odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Odor Threshold Low: 0.02 [ppm] | Haz-Map | |
| Odor Threshold High: 6.6 [ppm] | Haz-Map | ||
| Odor threshold from AIHA | Haz-Map |
O-Toluidine critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 443.85 °C (830.9 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
O-Toluidine fire and explosion behaviour
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
O-Toluidine fire potential
Flammable when exposed to heat or flame.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
O-Toluidine storage and handling
O-Toluidine safe storage
Provision to contain effluent from fire extinguishing. Separated from strong oxidants, strong acids and food and feedstuffs. Well closed. Ventilation along the floor. Keep in the dark. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
O-Toluidine storage conditions
Before entering confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. o-Toluidine must be stored to avoid contact with strong oxidizers (such as chlorine, bromine, and fluorine) because violent reactions occur. Store in tightly closed containers in a cool, well-ventilated area away from heat. Sources of ignition, such as smoking and open flames, are prohibited where o-toluidine is used, handled, or stored in a manner that could creats a potential fire or explosion hazard. A regulated, marked area should be established where this chemical is handled, used, or stored ...
Source: Hazardous Substances Data Bank (HSDB)
O-Toluidine incompatible materials
Hypergolic reaction with red fuming nitric acid. Can react with oxidizing materials.
Source: Hazardous Substances Data Bank (HSDB)
O-Toluidine reactivity
O-TOLUIDINE neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen may be generated in combination with strong reducing agents, such as hydrides. Emits very toxic oxides of nitrogen when heated to decomposition. Undergoes a hypergolic reaction with red fuming nitric acid [Kit and Evered, 1960, p. 239, 242].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check O-Toluidine in the storage compatibility matrix →
11 · Questions
O-Toluidine — frequently asked questions
What is the CAS number of O-Toluidine?
The CAS number of O-Toluidine is 95-53-4. Its EC number is 202-429-0.
What is the chemical formula of O-Toluidine?
The molecular formula of O-Toluidine is C7H9N and its molecular weight is 107.15 g/mol.
What does a O-Toluidine label have to show?
Under CLP Annex VI the label for O-Toluidine carries the pictograms Skull and crossbones, Health hazard and Environment and the signal word is Danger.
Is O-Toluidine flammable?
CLP Annex VI assigns O-Toluidine no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it. The flash point reported for it is 85 °C (185 °F) (HSDB).
Is O-Toluidine a carcinogen?
Yes. CLP Annex VI classifies O-Toluidine as a category 1A or 1B carcinogen and assigns it H350: may cause cancer. IARC places it in Group 1: carcinogenic to humans.
What is the exposure limit for O-Toluidine?
The US occupational exposure limit reported for O-Toluidine is 5.0 [ppm] (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.
What is the boiling point of O-Toluidine?
The boiling point reported for O-Toluidine is 200.3 °C (392.5 °F) (HSDB).
What is the melting point of O-Toluidine?
The melting point reported for O-Toluidine is -14.41 °C (6.1 °F) (HSDB).
How should O-Toluidine be stored?
Before entering confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. o-Toluidine must be stored to avoid contact with strong oxidizers (such as chlorine, bromine, and fluorine) because violent reactions occur. Store in tightly closed containers in a cool, well-ventilated area away from heat. Sources of ignition, such as smoking and open flames, are prohibited where o-toluidine is used, handled, or stored in a manner that could creats a potential fire or explosion hazard. A regulated, marked area should be established where this chemical is handled, used, or stored ... (Hazardous Substances Data Bank (HSDB))
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