Benzene

1Identification

Name

Benzene

IUPAC name

benzene

CAS number

71-43-2

EC number

200-753-7

Molecular formula

C6H6

Molecular weight

78.11 g/mol

InChIKey

UHOVQNZJYSORNB-UHFFFAOYSA-N

SMILES

C1=CC=CC=C1

PubChem CID

241

Synonyms

benzene, benzol, Cyclohexatriene, benzole, Pyrobenzole, Benzine, Coal naphtha, Pyrobenzol, Benzen, Phene, Phenyl hydride, Mineral naphtha, Benzolene, Bicarburet of hydrogen

Recommended uses

• Benzene is used as a constituent in motor fuels; as a solvent for fats, waxes, resins, oils, inks, paints, plastics, and rubber; in the extraction of oils from seeds and nuts; and in photogravure printing. It is also used as a chemical intermediate. Benzene is also used in the manufacture of detergents, explosives, pharmaceuticals, and dyestuffs.
  EPA Hazardous Air Pollutants
• Benzene was used in the past as a solvent in inks, rubber, lacquers, and paint removers. Today, it is used mainly in closed processes to synthesize organic chemicals. Gasoline in some countries contains a high concentration of benzene (as high as 30%); the U.S. average is 1-3%. Workers who remove or clean underground storage tanks may be exposed to significant levels. [ACGIH] Gasoline in North America now contains about 1% benzene. [AIHAJ 2002;63(2):225-30] The European Union (EU) reduced in 2000 the maximum allowed benzene content in gasoline from 5% to 1% by volume. Mean exposures in the Swedish petroleum industry are well below the Swedish occupational exposure limits. [PMID 28578463]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• EPA restricts benzene emission from specific point sources; maximum contaminant level in drinking water is 5 ppb; FDA prohibits the use of benzene in food; [ATSDR Case Studies]
  Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
• Binder Other Solvent pH regulating agent Fuel Heat transferring agent Fuel agents Surfactant (surface active agent) Not Known or Reasonably Ascertainable Catalyst Cleaning agent Plasticizer Flame retardant Laboratory chemicals Intermediate Processing aids, specific to petroleum production Adhesion/cohesion promoter
  EPA Chemical Data Reporting (CDR)
• Intermediate Etching agent Plasticizer Soil amendments (fertilizers) Not Known or Reasonably Ascertainable Catalyst Fuel Fuel agents Solvent Lubricating agent Other
  EPA Chemical Data Reporting (CDR)

Use categories: Chemical Classes -> Hydrocarbons (contain hydrogen and carbon atoms), Volatile organic compounds · Food Additives -> EXTRACTION_SOLVENT -> JECFA Functional Classes · SOLVENTS

Description

• Benzene is a colorless liquid with a sweet odor. It evaporates into the air very quickly and dissolves slightly in water. It is highly flammable and is formed from both natural processes and human activities. Benzene is widely used in the United States; it ranks in the top 20 chemicals for production volume. Some industries use benzene to make other chemicals which are used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline, and cigarette smoke.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Benzene can cause cancer according to California Labor Code. It can cause developmental toxicity and male reproductive toxicity according to an independent committee of scientific and health experts.
  California Office of Environmental Health Hazard Assessment (OEHHA)
• Benzene appears as a clear colorless liquid with a petroleum-like odor. Flash point less than 0 °F. Less dense than water and slightly soluble in water. Hence floats on water. Vapors are heavier than air.
  CAMEO Chemicals

2Hazard identification

Signal word

Danger

Pictograms

GHS02, GHS07, GHS08

Classification source

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

Precautionary statements

Other reported classifications

7 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)
• 3 - Liquids and solids that can be ignited under almost all ambient temperature conditions. Materials produce hazardous atmospheres with air under almost all ambient temperatures or, though unaffected by ambient temperatures, are readily ignited under almost all conditions.
  Hazardous Substances Data Bank (HSDB)
• 0 - Materials that in themselves are normally stable, even under fire conditions.
  Hazardous Substances Data Bank (HSDB)

Health hazards

• Dizziness, excitation, pallor, followed by flushing, weakness, headache, breathlessness, chest constriction, nausea, and vomiting. Coma and possible death. (USCG, 1999)
  CAMEO Chemicals
• · May cause toxic effects if inhaled or absorbed through skin. · Inhalation or contact with material may irritate or burn skin and eyes. · Fire will produce irritating, corrosive and/or toxic gases. · Vapors may cause dizziness or asphyxiation, especially when in closed or confined areas. · Runoff from fire control or dilution water may cause environmental contamination.
  Emergency Response Guidebook (ERG)

Fire hazards

• Behavior in Fire: Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back. (USCG, 1999)
  CAMEO Chemicals
• · 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.
  Emergency Response Guidebook (ERG)
• Highly flammable. Vapour/air mixtures are explosive. Risk of fire and explosion. See Chemical Dangers.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Hazards summary

• Benzene is a colorless liquid with a sweet odor. It evaporates into the air very quickly and dissolves slightly in water. It is highly flammable and is formed from both natural processes and human activities. Benzene is widely used in the United States; it ranks in the top 20 chemicals for production volume. Some industries use benzene to make other chemicals which are used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline, and cigarette smoke.
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Benzene is found in the air from emissions from burning coal and oil, gasoline service stations, and motor vehicle exhaust. Acute (short-term) inhalation exposure of humans to benzene may cause drowsiness, dizziness, headaches, as well as eye, skin, and respiratory tract irritation, and, at high levels, unconsciousness. Chronic (long-term) inhalation exposure has caused various disorders in the blood, including reduced numbers of red blood cells and aplastic anemia, in occupational settings. Reproductive effects have been reported for women exposed by inhalation to high levels, and adverse effects on the developing fetus have been observed in animal tests.
  EPA Hazardous Air Pollutants

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

• 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.
  CAMEO Chemicals
• General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).
  Emergency Response Guidebook (ERG)
• (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 immediately - If this chemical contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly. 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

• Dizziness. Drowsiness. Headache. Nausea. Shortness of breath. Convulsions. Unconsciousness.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• MAY BE ABSORBED! Dry skin. Redness. Pain. Further see Inhalation.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Redness. Pain.
  ILO-WHO International Chemical Safety Cards (ICSCs)

5Fire-fighting measures

• Approach fire from upwind to avoid hazardous vapors. Use water spray, dry chemical, foam, or carbon dioxide. Use water spray to keep fire-exposed containers cool.
  Hazardous Substances Data Bank (HSDB)
• If material on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use foam, dry chemical, or carbon dioxide.
  Hazardous Substances Data Bank (HSDB)
• Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
  Hazardous Substances Data Bank (HSDB)

6Accidental release measures

Isolation and evacuation

• Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]: 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
• 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.
  Emergency Response Guidebook (ERG)

Spill cleanup

• Remove all ignition sources. Evacuate danger area! Consult an expert! Personal protection: complete protective clothing including self-contained breathing apparatus. Do NOT wash away into sewer. Do NOT let this chemical enter the environment. 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.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• For spills on water, contain with booms or barriers, use surface acting agents to thicken spilled materials. Remove trapped materials with suction hoses.
  Hazardous Substances Data Bank (HSDB)
• Small spills of benzene can be taken up by sorption on carbon or synthetic sorbent resins. Flush area with water. For large quantities, if response is rapid, benzene can be skimmed off the surface. Straw may be used to mop slicks.
  Hazardous Substances Data Bank (HSDB)
• PRECAUTIONS FOR "CARCINOGENS": A high-efficiency particulate arrestor (HEPA) or charcoal filters can be used to minimize amt of carcinogen in exhausted air ventilated safety cabinets, lab hoods, glove boxes or animal rooms. ... Filter housing that is designed so that used filters can be transferred into plastic bag without contaminating maintenance staff is avail commercially. Filters should be placed in plastic bags immediately after removal. ... The plastic bag should be sealed immediately. ... The sealed bag should be labelled properly. ... Waste liquids ... should be placed or collected in proper containers for disposal. The lid should be secured & the bottles properly labelled.
  Hazardous Substances Data Bank (HSDB)

7Handling and storage

• Fireproof. Separated from food and feedstuffs, oxidants and halogens. Store in an area without drain or sewer access.
  ILO-WHO International Chemical Safety Cards (ICSCs)
• Keep in well closed containers in a cool place and away from fire.
  Hazardous Substances Data Bank (HSDB)
• PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practicable to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/
  Hazardous Substances Data Bank (HSDB)
• Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage.
  Hazardous Substances Data Bank (HSDB)

8Exposure controls / personal protection

Personal protective equipment

• Excerpt from NIOSH Pocket Guide for Benzene: 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 (FLAMMABLE) - Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100 °F). Change: No recommendation is made specifying the need for the worker to change clothing after the workshift.
  CAMEO Chemicals
• Protective clothing consisting of coveralls or other full body clothing should be worn and changed at least twice weekly.
  Hazardous Substances Data Bank (HSDB)
• Where there is a possibility of benzene contact to eyes or skin, safety showers, eye-wash fountains, and cleansing facilities shall be installed and maintained.
  Hazardous Substances Data Bank (HSDB)
• Where high vapor concn are unavoidable, forced air masks should be used. Lifeline attended by ... person outside contaminated enclosure is mandatory. If skin contact is unavoidable, neoprene gloves must be worn.
  Hazardous Substances Data Bank (HSDB)

Respirator recommendations

• (See OSHA respirator requirements for selected chemicals) NIOSH At concentrations above the NIOSH REL, or where there is no REL, at any detectable concentration: (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode (APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus Escape: (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister Any appropriate escape-ty…
  The National Institute for Occupational Safety and Health (NIOSH)

9Physical and chemical properties

10Stability and reactivity

Reactivity

• BENZENE reacts vigorously with allyl chloride or other alkyl halides even at -70 °C in the presence of ethyl aluminum dichloride or ethyl aluminum sesquichloride. Explosions have been reported [NFPA 491M 1991]. Ignites in contact with powdered chromic anhydride [Mellor 11:235 1946-47]. Incompatible with oxidizing agents such as nitric acid. Mixtures with bromine trifluoride, bromine pentafluoride, iodine pentafluoride, iodine heptafluoride and other interhalogens can ignite upon heating [Bretherick 5th ed. 1995]. Benzene and cyanogen halides yield HCl as a byproduct (Hagedorn, F. H. Gelbke, and Federal Republic of Germany. 2002. Nitriles. In Ullmann's Encyclopedia of Industrial Chemistry.
  CAMEO Chemicals
• Highly flammable. Slightly soluble in water.
  CAMEO Chemicals

Incompatible materials and hazardous reactions

• Reacts violently with iodine pentafluoride.
  Hazardous Substances Data Bank (HSDB)
• Hydrogenation of benzene to cyclohexane was effected in a fixed bed reactor at 210-230 °C, but a fall in conversion was apparent. Increasing the bed temp by 10 °C & the hydrogen flow led to a large increase in reaction rate which the interbed cooling coils could not handle, & an exotherm to 280 °C developed, with a hot spot around 600 °C which bulged the reactor wall.
  Hazardous Substances Data Bank (HSDB)
• Benzene ... ignites in contact with /iodine heptafluoride/ gas ...
  Hazardous Substances Data Bank (HSDB)

Chemical stability

• Stable under recommended storage conditions.
  Hazardous Substances Data Bank (HSDB)

11Toxicological information

Target organs

• Cancer, Gastrointestinal (Stomach and Intestines, part of the digestive system), Hematological (Blood Forming), Immunological (Immune System), Neurological (Nervous System)
  Agency for Toxic Substances and Disease Registry (ATSDR)
• Immune
  EPA Integrated Risk Information System (IRIS)

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. This may result in lowering of consciousness. Exposure far above the OEL could cause unconsciousness and death. If swallowed the substance easily enters the airways and could result in aspiration pneumonitis.
  ILO-WHO International Chemical Safety Cards (ICSCs)

Long-term exposure effects

• The substance defats the skin, which may cause dryness or cracking. The substance may have effects on the central nervous system and immune system. The substance may have effects on the bone marrow. This may result in anaemia. This substance is carcinogenic to humans. May cause heritable genetic damage to human germ cells.
  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

• Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number F005, U019, D018, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.
  Hazardous Substances Data Bank (HSDB)
• SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal.
  Hazardous Substances Data Bank (HSDB)
• Biodegradation, incineration: Benzene is biodegradable. Diluted aqueous soln, therefore, are drained into sewage treatment plants and decomposed there by anaerobic bacteria. Solvent mixtures and sludges of higher concn are burnt in special waste incinerators if a recovery process is uneconomical.
  Hazardous Substances Data Bank (HSDB)

14Transport information

UN number: UN 1114

Shipping name

• UN 1114; Benzene
  Hazardous Substances Data Bank (HSDB)
• IMO 3.2; Benzene
  Hazardous Substances Data Bank (HSDB)

DOT hazard class

• Benzene
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• UN1114
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172
• Class 3 Flammable and combustible liquid (49 eCFR § 173.120)
  US Code of Federal Regulations, Hazardous Materials, 49 CFR Part 172

DOT label

• Flammable Liquid
  CAMEO Chemicals

UN classification

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

Emergency Response Guidebook

• 1114 130
  Emergency Response Guidebook (ERG)

How DOT hazard classes work →

15Regulatory information

• National emission standard for equipment leaks (fugitive emission sources) of benzene prohibit detectable benzene emissions from processing equipment (eg, pumps, valves) that contains materials which have a benzene concn of 10% or more by wt.
  Hazardous Substances Data Bank (HSDB)
• Toxic pollutant designated pursuant to section 307(a)(1) of the Federal Water Pollution Control Act and is subject to effluent limitations.
  Hazardous Substances Data Bank (HSDB)
• Benzene is designated as a hazardous substance under section 311(b)(2)(A) of the Federal Water Pollution Control Act and further regulated by the Clean Water Act Amendments of 1977 and 1978. These regulations apply to discharges of this substance. This designation includes any isomers and hydrates, as well as any solutions and mixtures containing this substance.
  Hazardous Substances Data Bank (HSDB)
• Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 10 lb or 4.54 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV.D.3.b).
  Hazardous Substances Data Bank (HSDB)
• D018; A solid waste containing benzene may or may not become characterized as a hazardous waste when subjected to the Toxicity Characteristic Leaching Procedure listed in 40 CFR 261.24, and if so characterized, must be managed as a hazardous waste.
  Hazardous Substances Data Bank (HSDB)
• Benzene is an indirect food additive for use only as a component of adhesives.
  Hazardous Substances Data Bank (HSDB)

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

16Other information

Compiled from PubChem CID 241 and the sources it aggregates (attributed inline). Data retrieved 2026-10-12. This summary describes the pure substance and is not a supplier SDS.