1,2,4-Trimethylbenzene

1Identification

Name

1,2,4-Trimethylbenzene

IUPAC name

1,2,4-trimethylbenzene

CAS number

95-63-6

EC number

202-436-9

Molecular formula

C9H12

Molecular weight

120.19 g/mol

InChIKey

GWHJZXXIDMPWGX-UHFFFAOYSA-N

SMILES

CC1=CC(=C(C=C1)C)C

PubChem CID

7247

Synonyms

1,2,4-TRIMETHYLBENZENE, Pseudocumene, Pseudocumol, Psi-cumene, 1,3,4-Trimethylbenzene, Benzene, 1,2,4-trimethyl-, 1,2,5-Trimethylbenzene, Uns-trimethylbenzene, Asymmetrical trimethylbenzene, 1,2,4-trimethyl-benzene, Benzene, 1,2,5-trimethyl-, Assymetrical trimethylbenzene, RefChem:71555, .psi.-Cumene

Recommended uses

• Used for sterilizing catgut; as a solvent in manufacture of dyes, perfumes and resins; solvent for liquid scintillation counting solutions; in the manufacture of trimellitic anhydride, pharmaceuticals, pseudocumidine, and pyromellitic dianhydride; as a comonomer for pseudocumene-formaldehyde resins; as an industrial solvent and paint thinner; as vermifuge; [HSDB] Used in high octane fuels; It is present in gasoline and occurs in coal tar and many petroleum products. [CHEMINFO] See Trimethyl benzene, isomers.
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Petroleum Production and Refining [Category: Industry] Painting (Solvents) [Category: Paint]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Solvent for /classical/ liquid scintillation counting solutions.
  Hazardous Substances Data Bank (HSDB)
• Other Solvent Fuel Fuel agents Diluent Filler Corrosion inhibitor Sealant (barrier) Surface modifier Processing aids, specific to petroleum production Intermediate
  EPA Chemical Data Reporting (CDR)
• Solvent Fuel agents Fuel Sealant (barrier) Not Known or Reasonably Ascertainable Processing aids, specific to petroleum production Intermediate Surface modifier
  EPA Chemical Data Reporting (CDR)

Use categories: Fragrance Ingredients

Description

• 1,2,4-trimethylbenzene appears as a liquid. Flash point near 130 °F. Less dense than water and insoluble in water. Vapors irritate eyes, throat, and nose. Used in dyes and pharmaceuticals.
  CAMEO Chemicals
• 1,2,4-trimethylbenzene is a trimethylbenzene carrying methyl groups at positions 1, 2 and 4. It has a role as a neurotoxin.
  ChEBI
• 1,2,4-Trimethylbenzene is a colorless liquid with chemical formula C9H12. It is a flammable aromatic hydrocarbon with a strong odor. It occurs naturally in coal tar and petroleum (about 3%). It is nearly insoluble in water, but well-soluble in ethanol, diethyl ether, and benzene.
  Toxin and Toxin Target Database (T3DB)

2Hazard identification

Signal word

Warning

Pictograms

GHS02, GHS07, GHS09

Classification source

Regulation (EC) No 1272/2008 of the European Parliament and of the Council

Precautionary statements

Other reported classifications

5 classification records exist across sources. Differences usually reflect purity, physical form or impurities.

NFPA 704 rating

• 1 - Materials that, under emergency conditions, can cause significant irritation.
  Hazardous Substances Data Bank (HSDB)
• 2 - Materials that must be moderately heated or exposed to relatively high ambient temperatures before ignition can occur. Materials would not under normal conditions form hazardous atmospheres with air, but under high ambient temperatures or under moderate heating could release vapor in sufficient quantities to produce hazardous atmospheres with air.
  Hazardous Substances Data Bank (HSDB)
• 0 - Materials that in themselves are normally stable, even under fire conditions.
  Hazardous Substances Data Bank (HSDB)

Health hazards

• Harmful if inhaled or swallowed. Vapor or mist is irritating to the eyes, mucous membrane and upper respiratory tract. Prolonged contact can cause dermatitis, nausea, headache, dizziness, and narcotic effect. (USCG, 1999)
  CAMEO Chemicals

Fire hazards

• Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids will float on water. Substance may be transported hot.
  CAMEO Chemicals
• Flammable. Above 44 °C explosive vapour/air mixtures may be formed.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Hazards summary

• A skin, eye, and respiratory tract irritant; Inhalation of high concentrations can cause CNS depression; [HSDB] A skin, eye, and respiratory tract irritant; May cause chemical pneumonitis after aspiration; Defats the skin; May have effects on the central nervous system and blood; [ICSC] Reported blood dycrasias in chronically exposed workers were probably caused by benzene present as a contaminant; [ACGIH] An irritant; [MSDSonline] See Trimethyl benzene isomers.
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• The major hazards encountered in the use and handling of 1,2,4-trimethylbenzene stem from its toxicologic properties. Toxic by inhalation and dermal contact, exposure to this liquid may occur from its use as a solvent and paint thinner, and in the manufacture of dyes, perfumes, resins, pharmaceuticals, and trimellitic anhydride. Effects from exposure may include headache, fatigue, nausea, irritation of the skin, eyes, and mucous membranes, central nervous system depression, asthmatic bronchitis, chemical pneumonitis, or pulmonary edema.
  Hazardous Substances Data Bank (HSDB)

3Composition / information on ingredients

This page describes the pure substance. Commercial products may be solutions or mixtures. Check Section 3 of your supplier's SDS for concentrations and other ingredients.

4First-aid measures

• Excerpt from NIOSH Pocket Guide for 1,2,4-Trimethylbenzene: 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 WASH - If this chemical contacts the skin, wash the contaminated skin with soap and water. Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.
  CAMEO Chemicals
• (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 wash - If this chemical contacts the skin, wash the contaminated skin with soap and water. Breathing: Respiratory support Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.
  The National Institute for Occupational Safety and Health (NIOSH)

Symptoms of exposure

• Confusion. Cough. Dizziness. Drowsiness. Headache. Sore throat. Vomiting.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Dry skin.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• This chemical is a flammable liquid. Poisonous gases are produced in fire. Small fires: dry chemical, carbon dioxide, water spray, or alcohol-resistant foam. Large fires: water spray, fog, or alcohol foam. Move container from fire if you can do so without risk. Spray cooling water on containers that are exposed to flames until well after fire is out. For massive fire in cargo area, use unmanned hose holder or monitoring nozzles; if this is impossible, withdraw from area and let fire burn. Isolate for one-half mile in all directions if tank car or truck is involved in fire. Vapors are heavier than air and will collect in low areas.
  Hazardous Substances Data Bank (HSDB)

Hazardous combustion products

• The substance decomposes on burning producing toxic and irritating fumes.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]: IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions. LARGE SPILL: Consider initial downwind evacuation for at least 300 meters (1000 feet). FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)
  CAMEO Chemicals

Spill cleanup

• Personal protection: filter respirator for organic gases and vapours adapted to the airborne concentration of the substance. Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations. Do NOT wash away into sewer. Do NOT let this chemical enter the environment.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Establish forced ventilation to keep levels below explosive limit. Absorb liquids in vermiculite, dry sand, earth, peat, carbon, or similar material and deposit in sealed containers. Keep this chemical out of a confined space ... because of the possibility of an explosion ... It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Fireproof. Separated from strong oxidants. Well closed. Keep in a well-ventilated room.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Prior to working with this chemical you should be trained on its proper handling and storage. Before entering a confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. Trimethylbenzene must be stored to avoid contact with oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates), and strong oxidizers (such as chlorine, bromine, and fluorine) since violent reactions occur. Store in tightly closed containers in a cool, well-ventilated area away from heat.
  Hazardous Substances Data Bank (HSDB)
• STORAGE TANKS SHOULD BE MOUNDED TO CONFINE ESCAPING LIQUID & ESCAPE FROM PROCESS VESSELS SHOULD BE CONTROLLED IN SIMILAR MANNER BY SILLS @ DOORWAYS, DESIGN OF FLOORS, ETC. /TRIMETHYLBENZENES/
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• Excerpt from NIOSH Pocket Guide for 1,2,4-Trimethylbenzene: Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact. Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact. Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated. Remove: WHEN WET OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced. Change: No recommendation is made specifying the need for the worker to change clothing after the workshift. (NIOSH, 2024)
  CAMEO Chemicals
• Wear appropriate personal protective clothing to prevent skin contact.
  Hazardous Substances Data Bank (HSDB)
• Wear appropriate eye protection to prevent eye contact.
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• Important additional information about respirator selection
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• 1,2,4-TRIMETHYLBENZENE is incompatible with the following: Oxidizers, nitric acid (NIOSH, 2024).
  CAMEO Chemicals
• Insoluble in water.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• Oxidizers (perchlorates, peroxides, permanganates, chlorates, nitrates), strong oxidizers (chlorine, bromine, fluorine), and nitric acid. /Trimethyl benzenes/
  Hazardous Substances Data Bank (HSDB)
• Oxidizers, nitric acid.
  Hazardous Substances Data Bank (HSDB)
• Oxidizers, nitric acid
  The National Institute for Occupational Safety and Health (NIOSH)

11Toxicological information

Target organs

• Developmental Hematologic Nervous Respiratory
  EPA Integrated Risk Information System (IRIS)
• Eyes, skin, respiratory system, central nervous system, blood
  The National Institute for Occupational Safety and Health (NIOSH)

Short-term exposure effects

• The substance is irritating to the eyes, skin and respiratory tract. If this liquid is swallowed, aspiration into the lungs may result in chemical pneumonitis. The substance may cause effects on the central nervous system.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• The substance defats the skin, which may cause dryness or cracking. Repeated or prolonged inhalation may cause effects on the lungs. This may result in chronic bronchitis. The substance may have effects on the central nervous system and blood.
  ILO-WHO International Chemical Safety Cards (ICSCs)

12Ecological information

Not available in the public sources we compile. Check Section 12 of the supplier's SDS.

13Disposal considerations

• SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.
  Hazardous Substances Data Bank (HSDB)
• Incineration /SRP: with appropriate emission controls/. /Trimethyl benzenes/
  Hazardous Substances Data Bank (HSDB)

14Transport information

DOT label

• Flammable Liquid
  CAMEO Chemicals

UN classification

• UN Hazard Class: 3; UN Pack Group: III
  ILO-WHO International Chemical Safety Cards (ICSCs)

Not available in the public sources we compile. Check Section 14 of the supplier's SDS.

How DOT hazard classes work →

15Regulatory information

• Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. 1,2,4-Trimethylbenzene is included on this list. Effective date 4/29/1983; Sunset date 4/29/1993.
  Hazardous Substances Data Bank (HSDB)

Overview of SDS regulations (OSHA HazCom, WHMIS, REACH/CLP) →

16Other information

Compiled from PubChem CID 7247 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.