Substance profile
Benzene
Benzene is a clear, colorless liquid with an aromatic odor.
01 · Identification
What Benzene is
Benzene is a clear, colorless liquid with an aromatic odor. Its molecular formula is C6H6 and its molecular weight is 78.11 g/mol. It boils at 80.1 °C, melts at 5.6 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Benzene identifiers and molecular data
Benzene CAS number and EC number
Benzene molecular formula and molecular weight
Other names for Benzene
- benzol
- C6H6
- (6)Annulene
- Benzin
- Benzine
- Benzole
- Benzolene
- Bicarburet Of Hydrogen
- Carbon Oil
- Coal Naphtha
- Cyclohexatriene
- 1,3,5-Cyclohexatriene
- Mineral Naphtha
- Motor Benzol
03 · GHS classification
Benzene hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Benzene pictograms and signal word
Benzene hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable liquids GHS chapter 2.6 | Category 2 | H225 | GHS02 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 2 | H315 | GHS07 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 2A | H319 | GHS07 |
| Germ cell mutagenicity GHS chapter 3.5 | Category 1A or 1B | H340 | GHS08 |
| Carcinogenicity GHS chapter 3.6 | Category 1A or 1B | H350 | GHS08 |
| Specific target organ toxicity - repeated exposure GHS chapter 3.9 | Category 1 | H372 | GHS08 |
| Aspiration hazard GHS chapter 3.10 | Category 1 | H304 | GHS08 |
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.
Benzene hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H225 | Highly flammable liquid and vapour. |
| H350 | May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H340 | May cause genetic defects <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H304 | May be fatal if swallowed and enters airways. |
| H372 | Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H315 | Causes skin irritation. |
| H319 | Causes serious eye irritation. |
This page lists only the codes assigned to Benzene. 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 Benzene
Our own Benzene safety data sheet walks through all sixteen sections of the published data. What it is not is the document an inspector asks for: an SDS is issued for a product by its supplier, so the sheet covering the grade actually standing in your store exists only in that supplier’s version. Collecting those and keeping them current as suppliers revise them is a separate job.
04 · Precautionary statements
Benzene precautionary statements
CLP Annex VI assigns 19 precautionary statements to Benzene. 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.
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
Benzene 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 | бензен |
| Spanish español | Benceno |
| Czech čeština | benzen |
| Danish dansk | benzen |
| German Deutsch | Benzol |
| Estonian eesti | benseen |
| Greek ελληνικά | βενζόλιο |
| English English | benzene |
| French français | benzène |
| Croatian hrvatski | benzen |
| Italian italiano | benzene |
| Latvian latviešu | benzols |
| Lithuanian lietuvių | benzenas |
| Hungarian magyar | benzol |
| Maltese Malti | benżen |
| Dutch Nederlands | benzeen |
| Polish polski | benzen |
| Portuguese português | benzeno |
| Romanian română | benzen |
| Slovak slovenčina | benzén |
| Slovenian slovenščina | benzen |
| Finnish suomi | bentseeni |
| Swedish svenska | bensen |
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
Benzene GHS label elements
Everything CLP Annex VI fixes for Benzene, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Benzene
- Highly flammable liquid and vapour.
- May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- May cause genetic defects <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- May be fatal if swallowed and enters airways.
- Causes damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- Causes skin irritation.
- Causes serious eye irritation.
- Obtain special instructions before use.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Use explosion-proof [electrical/ventilating/lighting/…] equipment.
- Use only non-sparking tools.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Wash … thoroughly after handling.
- Do not eat, drink or smoke when using this product.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF ON SKIN:
- IF IN EYES:
- IF exposed or concerned:
- Get medical advice/attention.
- Get medical advice/attention if you feel unwell.
- If skin irritation occurs:
- If eye irritation persists:
- Remove contact lenses, if present and easy to do. Continue rinsing.
- Wash with plenty of water/…
- Store in a well-ventilated place.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Benzene in the GHS label constructor →
07 · Health hazards
Benzene health hazards and exposure limits
Benzene hazard 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.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Benzene carcinogenicity classification
Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenicity of benzene for male F344/N rats, for female F344/N rats, for male B6C3F1 mice, and for female B6C3F1 mice. For male rats, benzene caused increased incidences of Zymbal gland carcinomas, squamous cell papillomas and squamous cell carcinomas of the oral cavity, and squamous cell papillomas and squamous cell carcinomas of the skin. For female rats, benzene caused increased incidences of Zymbal gland carcinomas and squamous cell papillomas and squamous cell carcinomas of the oral cavity. For male mice, benzene caused increased incidences of Zymbal gland squamous cell carcinomas, malignant lymphomas, alveolar/bronchiolar carcinomas and alveolar/bronchiolar adenomas or carcinomas (combined), harderian gland adenomas, and squamous cell carcinomas of the preputial gland. For female mice, benzene caused increased incidences of malignant lymphomas, ovarian granulosa cell tumors, ovarian benign mixed tumors, carcinomas and carcinosarcomas of the mammary gland, alveolar/bronchiolar adenomas, alveolar/bronchiolar carcinomas, and Zymbal gland squamous cell carcinomas. Dose-related lymphocytopenia was observed for male and female F344/N rats and male and female B6C3F1 mice.
Source: US National Toxicology Program · TR-289: Toxicology and Carcinogenesis Studies of Benzene (CASRN 71-43-2) in F344/N Rats and B6C3F1 Mice (Gavage Studies) (1986 )
Classification of carcinogenicity: 1) evidence in humans: sufficient; 2) evidence in animals: sufficient; Overall summary evaluation of carcinogenic risk to humans is group 1: The chemical is carcinogenic to humans. /From table/
Source: Hazardous Substances Data Bank (HSDB)
Cancer Classification: Carcinogenic to Humans
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.
Benzene occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 1.0 [ppm], STEL(OSHA) = 5 ppm (see CFR 1910.1028) | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 1 ppm | Occupational Safety and Health Administration (OSHA) |
| PEL | 5 ppm | Occupational Safety and Health Administration (OSHA) |
| REL | 0.1 ppm | Occupational Safety and Health Administration (OSHA) |
| REL | 1 ppm | Occupational Safety and Health Administration (OSHA) |
| REL | Ca TWA 0.1 ppm ST 1 ppm See Appendix A | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 500 ppm ; A potential occupational carcinogen. (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 500.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | NIOSH usually recommends that occupational exposures to carcinogens be limited to the lowest feasible concentration. | 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
Benzene 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.
Benzene boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 80.08 °C (176.1 °F) | HSDB | |
| 80 °C (176 °F) | NIOSH | ||
| 80.11 °C (176.2 °F) | at 760 mmHg | CAMEO |
Benzene melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 5.56 °C (42 °F) | HSDB | |
| 5.5 °C (41.9 °F) | CAMEO |
Benzene density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.88 g/cm³ | NIOSH | |
| 0.8756 g/cm³ | at 20 °C | HSDB | |
| 0.879 g/cm³ | at 20 °C | CAMEO |
Benzene solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Miscible with alcohol, chloroform, ether, carbon disulfide, acetone, oils, carbon tetrachloride, and glacial acetic acid | HSDB | |
| Miscible with ethanol, ethyl ether, acetone, chloroform; coluble in carbon tetrachloride | HSDB | ||
| In water, 1.79X10+3 mg/L at 25 °C | at 25 °C | HSDB |
Benzene vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 75 mmHg | NIOSH | |
| 75.0062 mmHg | at 20 °C | ICSC | |
| 94.8 mmHg | at 25 °C | HSDB |
Benzene flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | -11.11 °C (12 °F) | HSDB | |
| -11 °C (12.2 °F) | HSDB |
Benzene autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 497.78 °C (928 °F) | HSDB | |
| 591.67 °C (1097 °F) | CAMEO | ||
| 498 °C (928.4 °F) | ICSC |
Benzene lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 1.2 % by volume | HSDB | |
| 1.4 % by volume | HSDB |
Benzene upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 7.8 % by volume | HSDB | |
| 8 % by volume | HSDB |
Benzene vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 2.8 (air = 1) | HSDB | |
| 2.77 (air = 1) | CAMEO | ||
| 2.7 (air = 1) | ICSC |
Benzene odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | 4.68 PPM | HSDB | |
| In air: 4.9 mg/cu m (characteristic odor), in water: 2.0 mg/l. | HSDB | ||
| distinct odor: 310 mg/cu m= 90 ppm | HSDB |
Benzene critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 288.85 °C (551.9 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Benzene 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.
Benzene fire potential
A dangerous fire hazard when exosed to heat or flame. ... Ignites on contact with sodium peroxide + water, dioxygenyl tetrafluoroborate, iodine heptafluoride, and dioxygen difluoride.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Benzene storage and handling
Benzene reactive group
CAMEO Chemicals places Benzene in the reactive group Hydrocarbons, Aromatic. Compatibility with other chemicals is worked out from the group, not from the individual substance — which is why two substances you have never seen react can still be flagged as a pair that must be separated.
A reactive group is a CAMEO Chemicals (US NOAA) grouping, not a GHS hazard class: it has no code, no category and no legal force. It is what the storage compatibility matrix on this site computes from.
Benzene safe storage
Fireproof. Separated from food and feedstuffs, oxidants and halogens. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Benzene storage conditions
Keep in well closed containers in a cool place and away from fire.
Source: Hazardous Substances Data Bank (HSDB)
Benzene incompatible materials
Reacts violently with iodine pentafluoride.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Benzene in the storage compatibility matrix →
11 · Transport
Benzene UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
Benzene under UN 1114 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| BENZENE | 3 | F1 | II | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 3 is “Flammable liquids” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Benzene | 3 | II | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 3 is “Flammable and combustible liquid” (49 CFR 173.2).
12 · Questions
Benzene — frequently asked questions
What is the CAS number of Benzene?
The CAS number of Benzene is 71-43-2. Its EC number is 200-753-7.
What is the chemical formula of Benzene?
The molecular formula of Benzene is C6H6 and its molecular weight is 78.11 g/mol.
What does a Benzene label have to show?
Under CLP Annex VI the label for Benzene carries the pictograms Flame, Health hazard and Exclamation mark and the signal word is Danger.
Is Benzene flammable?
Yes. CLP Annex VI assigns Benzene H225 — highly flammable liquid and vapour. The flash point reported for it is -11.11 °C (12 °F) (HSDB).
Is Benzene a carcinogen?
Yes. CLP Annex VI classifies Benzene 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 Benzene?
The US occupational exposure limit reported for Benzene is 1.0 [ppm], STEL(OSHA) = 5 ppm (see CFR 1910.1028) (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 Benzene?
The boiling point reported for Benzene is 80.08 °C (176.1 °F) (HSDB).
What is the melting point of Benzene?
The melting point reported for Benzene is 5.56 °C (42 °F) (HSDB).
How should Benzene be stored?
CLP Annex VI assigns Benzene the storage statement P403. Keep in well closed containers in a cool place and away from fire. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Benzene
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