Substance profile
Hexachlorobenzene
Hexachlorobenzene is white needles.
01 · Identification
What Hexachlorobenzene is
Hexachlorobenzene is white needles. Its molecular formula is C6Cl6 and its molecular weight is 284.8 g/mol. It boils at 325 °C, melts at 229 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Hexachlorobenzene identifiers and molecular data
Hexachlorobenzene CAS number and EC number
Hexachlorobenzene molecular formula and molecular weight
03 · GHS classification
Hexachlorobenzene hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Hexachlorobenzene pictograms and signal word
Hexachlorobenzene hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| 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 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
| Hazardous to the aquatic environment - chronic GHS chapter 4.1 | Category 1 | H410 | 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.
Hexachlorobenzene 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>. |
| 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>. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
This page lists only the codes assigned to Hexachlorobenzene. 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 Hexachlorobenzene
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 Hexachlorobenzene 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
Hexachlorobenzene precautionary statements
CLP Annex VI assigns 10 precautionary statements to Hexachlorobenzene. 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
Hexachlorobenzene 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 | хексахлоробензен |
| Spanish español | Hexaclorobenceno |
| Czech čeština | hexachlorbenzen |
| Danish dansk | hexachlorbenzen |
| German Deutsch | Hexachlorbenzol |
| Estonian eesti | heksaklorobenseen |
| Greek ελληνικά | εξαχλωροβενζόλιο |
| English English | hexachlorobenzene |
| French français | hexachlorobenzène |
| Croatian hrvatski | heksaklorbenzen |
| Italian italiano | esaclorobenzene |
| Latvian latviešu | heksahlorbenzols |
| Lithuanian lietuvių | heksachlorbenzenas |
| Hungarian magyar | hexaklórbenzol |
| Maltese Malti | eżaklorobenżen |
| Dutch Nederlands | hexachloorbenzeen |
| Polish polski | heksachlorobenzen |
| Portuguese português | hexaclorobenzeno |
| Romanian română | hexaclorbenzen |
| Slovak slovenčina | hexachlórbenzén |
| Slovenian slovenščina | heksaklorobenzen |
| Finnish suomi | heksaklooribentseeni |
| Swedish svenska | hexaklorbensen |
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
Hexachlorobenzene GHS label elements
Everything CLP Annex VI fixes for Hexachlorobenzene, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Hexachlorobenzene
- May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- 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>.
- Very toxic to aquatic life.
- Very toxic to aquatic life with long lasting effects.
- Obtain special instructions before use.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Do not eat, drink or smoke when using this product.
- Avoid release to the environment.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF exposed or concerned:
- Get medical advice/attention.
- Get medical advice/attention if you feel unwell.
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Hexachlorobenzene in the GHS label constructor →
07 · Health hazards
Hexachlorobenzene health hazards and exposure limits
Hexachlorobenzene hazard summary
Hexachlorobenzene was widely used as a pesticide to protect the seeds of onions and sorghum, wheat, and other grains against fungus until 1965. It was also used to make fireworks, ammunition, and synthetic rubber. Currently, there are no commercial uses of hexachlorobenzene in the United States. Hexachlorobenzene is a white crystalline solid that is not very soluble in water. It does not occur naturally in the environment. It is formed as a by-product while making other chemicals, in the waste streams of chloralkali and wood-preserving plants, and when burning municipal waste.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Hexachlorobenzene carcinogenicity classification
Evaluation: There is inadequate evidence in humans for the carcinogenicity of hexachlorobenzene. There is sufficient evidence in experimental animals for the carcinogenicity of hexachlorobenzene. Overall evaluation: Hexachlorobenzene is possibly carcinogenic to humans (Group 2B).
Source: Hazardous Substances Data Bank (HSDB)
CLASSIFICATION: B2; probable human carcinogen. BASIS FOR CLASSIFICATION: Hexachlorobenzene, when administered orally, has been shown to induce tumors in the liver, thyroid, and kidney in three rodent species. HUMAN CARCINOGENICITY DATA: Inadequate. ANIMAL CARCINOGENICITY DATA: Sufficient.
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.
08 · Physical and chemical properties
Hexachlorobenzene 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.
Hexachlorobenzene boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 325 °C (617 °F) | HSDB | |
| 322.22 °C (612 °F) | OSHA | ||
| 325 °C (617 °F) | at 760 mmHg | DOE PAC |
Hexachlorobenzene melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 228.83 °C (443.9 °F) | HSDB | |
| 200 °C (392 °F) | Technical product | HSDB | |
| 231 °C (447.8 °F) | ICSC |
Hexachlorobenzene density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 2 g/cm³ | ICSC | |
| 2.044 g/cm³ | at 23 °C | HSDB | |
| 2.044 g/cm³ | at 24 °C | CAMEO |
Hexachlorobenzene solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Sparingly soluble in cold alcohol; soluble in benzene, chloroform, and ether | HSDB | |
| Soluble in carbon disulfide; sparingly soluble in carbon tetrachloride | HSDB | ||
| In water, 4.7X10-3 mg/L at 25 °C | at 25 °C | HSDB |
Hexachlorobenzene vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.000007501 mmHg | at 20 °C | ICSC |
| 0.0000172 mmHg | at 25 °C | HSDB | |
| 1 mmHg | at 114.39 °C | CAMEO |
Hexachlorobenzene flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 242 °C (467.6 °F) | closed cup | HSDB |
| 242.22 °C (468 °F) | CAMEO | ||
| 242 °C (467.6 °F) | ICSC |
Hexachlorobenzene vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 9.83 (air = 1) | HSDB | |
| 9.8 (air = 1) | CAMEO |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Hexachlorobenzene 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.
Hexachlorobenzene fire potential
Not flammable or combustible.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Hexachlorobenzene storage and handling
Hexachlorobenzene safe storage
Separated from food and feedstuffs. Well closed. Store only in original container. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Hexachlorobenzene storage conditions
Separated from food and feedstuffs. Well closed.
Source: Hazardous Substances Data Bank (HSDB)
Hexachlorobenzene incompatible materials
DIMETHYL FORMAMIDE AND HEXACHLOROBENZENE REACT VIOLENTLY ABOVE 65 °C.
Source: Hazardous Substances Data Bank (HSDB)
Hexachlorobenzene reactivity
HEXACHLOROBENZENE reacts violently with dimethylformamide. (NTP, 1992).
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Hexachlorobenzene in the storage compatibility matrix →
11 · Transport
Hexachlorobenzene 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.
Hexachlorobenzene under UN 2729 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| HEXACHLOROBENZENE | 6.1 | T2 | III | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 6.1 is “Toxic substances” (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) |
|---|---|---|---|
| Hexachlorobenzene | 6.1 | III | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 6.1 is “Poisonous materials” (49 CFR 173.2).
12 · Questions
Hexachlorobenzene — frequently asked questions
What is the CAS number of Hexachlorobenzene?
The CAS number of Hexachlorobenzene is 118-74-1. Its EC number is 204-273-9.
What is the chemical formula of Hexachlorobenzene?
The molecular formula of Hexachlorobenzene is C6Cl6 and its molecular weight is 284.8 g/mol.
What does a Hexachlorobenzene label have to show?
Under CLP Annex VI the label for Hexachlorobenzene carries the pictograms Health hazard and Environment and the signal word is Danger.
Is Hexachlorobenzene flammable?
CLP Annex VI assigns Hexachlorobenzene 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 242 °C (467.6 °F), closed cup (HSDB).
Is Hexachlorobenzene a carcinogen?
Yes. CLP Annex VI classifies Hexachlorobenzene as a category 1A or 1B carcinogen and assigns it H350: may cause cancer. IARC places it in Group 2B: possibly carcinogenic to humans.
What is the boiling point of Hexachlorobenzene?
The boiling point reported for Hexachlorobenzene is 325 °C (617 °F) (HSDB).
What is the melting point of Hexachlorobenzene?
The melting point reported for Hexachlorobenzene is 228.83 °C (443.9 °F) (HSDB).
How should Hexachlorobenzene be stored?
Separated from food and feedstuffs. Well closed. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Hexachlorobenzene
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