Substance profile
Styrene
Styrene is a colorless to yellowish, oily liquid with a characteristic, sweet, balsamic, almost floral odor that is extremely.
01 · Identification
What Styrene is
Styrene is a colorless to yellowish, oily liquid with a characteristic, sweet, balsamic, almost floral odor that is extremely. Its molecular formula is C8H8 and its molecular weight is 104.15 g/mol. It boils at 145 °C, melts at -30.6 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Styrene identifiers and molecular data
Styrene CAS number and EC number
Styrene molecular formula and molecular weight
Other names for Styrene
- vinylbenzene
- styrene monomer
- Cinnamene
- Cinnamenol
- Cinnamol
- Diarex Hf 77
- Ethenyl Benzene
- Ethenylbenzene
- Phenethylene
- Phenylethene
- Phenylethylene
- Styrol
- Styrole
- Styrolene
03 · GHS classification
Styrene hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Styrene pictograms and signal word
Styrene hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable liquids GHS chapter 2.6 | Category 3 | H226 | GHS02 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 4 | H332 | GHS07 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 2 | H315 | GHS07 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 2A | H319 | GHS07 |
| Specific target organ toxicity - repeated exposure GHS chapter 3.9 | Category 1 | H372 | GHS08 |
Styrene hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H226 | Flammable liquid and vapour. |
| H361d | Suspected of damaging the unborn child. |
| H332 | Harmful if inhaled. |
| 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 Styrene. 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 Styrene
Our own Styrene 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
Styrene precautionary statements
CLP Annex VI assigns 20 precautionary statements to Styrene. 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
Styrene 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 | стирен |
| Spanish español | Estireno |
| Czech čeština | styren |
| Danish dansk | styren |
| German Deutsch | Styrol |
| Estonian eesti | stüreen |
| Greek ελληνικά | στυρόλιο |
| English English | styrene |
| French français | styrène |
| Croatian hrvatski | stiren |
| Italian italiano | stirene |
| Latvian latviešu | stirols |
| Lithuanian lietuvių | stirenas |
| Hungarian magyar | sztirol |
| Maltese Malti | stiren |
| Dutch Nederlands | styreen |
| Polish polski | styren winylobenzen |
| Portuguese português | estireno |
| Romanian română | stiren |
| Slovak slovenčina | styrén |
| Slovenian slovenščina | stiren |
| Finnish suomi | styreeni |
| Swedish svenska | styren |
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
Styrene GHS label elements
Everything CLP Annex VI fixes for Styrene, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Styrene
- Flammable liquid and vapour.
- Suspected of damaging the unborn child.
- Harmful if inhaled.
- 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.
- 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.
- Use only outdoors or in a well-ventilated area.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF ON SKIN:
- IF INHALED:
- IF IN EYES:
- Call a POISON CENTER/doctor/… if you feel unwell.
- 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 Styrene in the GHS label constructor →
07 · Health hazards
Styrene health hazards and exposure limits
Styrene hazard summary
Styrene is primarily a synthetic chemical. It is also known as vinylbenzene, ethenylbenzene, cinnamene, or phenylethylene. It's a colorless liquid that evaporates easily and has a sweet smell. It often contains other chemicals that give it a sharp, unpleasant smell. It dissolves in some liquids but doesn't dissolve easily in water. Billions of pounds are produced each year to make products such as rubber, plastic, insulation, fiberglass, pipes, automobile parts, food containers, and carpet backing. Most of these products contain styrene linked together in a long chain (polystyrene) as well as unlinked styrene. Low levels of styrene also occur naturally in a variety of foods such as fruits, vegetables, nuts, beverages, and meats.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Styrene carcinogenicity classification
Studied by the US National Toxicology Program: TR-185: Bioassay of Styrene for Possible Carcinogenicity (CASRN 100-42-5) (1979 )
Styrene is reasonably anticipated to be a human carcinogen based on limited evidence of carcinogenicity from studies in humans, sufficient evidence of carcinogenicity from studies in experimental animals, and supporting data on mechanisms of carcinogenesis.
Source: Hazardous Substances Data Bank (HSDB)
Evaluation: There is limited evidence in humans for the carcinogenicity of styrene. There is limited evidence in experimental animals for the carcinogenicity of styrene. Styrene is possibly carcinogenic to humans (Group 2B).
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.
Styrene occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 100.0 [ppm], Ceiling(OSHA) = 200 ppm(600 ppm is 5-min. peak in any 3 hrs.) | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 100 ppm | Occupational Safety and Health Administration (OSHA) |
| PEL | 200 ppm; 600 ppm (Peak) for a single time period up to 5 min in any 3 hours | Occupational Safety and Health Administration (OSHA) |
| REL | 50 ppm (215 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | 100 ppm (425 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 50 ppm (215 mg/m3) ST 100 ppm (425 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 700 ppm (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 700.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 700 ppm | 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
Styrene 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.
Styrene boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 145.3 °C (293.5 °F) | HSDB | |
| 145 °C (293 °F) | NIOSH |
Styrene melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -30.65 °C (-23.2 °F) | HSDB | |
| -30.56 °C (-23 °F) | NIOSH | ||
| -30.6 °C (-23.1 °F) | ICSC |
Styrene density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.91 g/cm³ | NIOSH | |
| 0.906 g/cm³ | at 20 °C | CAMEO | |
| 0.9016 g/cm³ | at 25 °C | HSDB |
Styrene solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Insoluble in water | HSDB | |
| Soluble in ethanol, ether, and acetone; miscible with benzene; slightly soluble in carbon tetrachloride | HSDB | ||
| In water, 300 mg/L at 25 °C | at 25 °C | HSDB |
Styrene vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 5 mmHg | NIOSH | |
| 5.0254 mmHg | at 20 °C | ICSC | |
| 6.4 mmHg | at 25 °C | HSDB |
Styrene flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 32 °C (89.6 °F) | HSDB | |
| 31.11 °C (88 °F) | HSDB | ||
| 34.4 °C (93.9 °F) | Tag closed cup | HSDB |
Styrene autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 490 °C (914 °F) | HSDB |
Styrene lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 0.9 % by volume | HSDB | |
| 1.1 % by volume | HSDB |
Styrene upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 6.8 % by volume | HSDB | |
| 6.1 % by volume | HSDB |
Styrene vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 3.6 (air = 1) | HSDB |
Styrene odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Detection in water: 0.73 ppm; Chemically pure | HSDB | |
| Recognition in air: 0.047 ppm; Chemically pure | HSDB | ||
| Odor Threshold Range: 0.15 to 25 ppm | HSDB |
Styrene critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 363.7 °C (686.7 °F) | HSDB |
Styrene corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Styrene will corrode copper and copper alloys | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Styrene 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.
Styrene fire potential
Flammable liquid. /Styrene monomer, inhibited/
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Styrene storage and handling
Styrene reactive group
CAMEO Chemicals places Styrene in the reactive groups Hydrocarbons, Aliphatic Unsaturated, Hydrocarbons, Aromatic, Polymerizable Compounds. 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.
Styrene peroxide formation
C: Compounds that autopolymerize due to peroxide formation if inhibitors are depleated or not present
Source: Lab and Research Safety, University of Minnesota
Styrene safe storage
Fireproof. Separated from incompatible materials. See Chemical Dangers. Cool. Keep in the dark. Store only if stabilized. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Styrene storage conditions
Fireproof. Separated from incompatible materials. See Chemical Dangers. Cool. Keep in the dark. Store only if stabilized. Store in an area without drain or sewer access.
Source: Hazardous Substances Data Bank (HSDB)
Styrene incompatible materials
Incompatible materials: Oxidizing agents, copper.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Styrene in the storage compatibility matrix →
11 · Questions
Styrene — frequently asked questions
What is the CAS number of Styrene?
The CAS number of Styrene is 100-42-5. Its EC number is 202-851-5.
What is the chemical formula of Styrene?
The molecular formula of Styrene is C8H8 and its molecular weight is 104.15 g/mol.
What does a Styrene label have to show?
Under CLP Annex VI the label for Styrene carries the pictograms Flame, Health hazard and Exclamation mark and the signal word is Danger.
Is Styrene flammable?
Yes. CLP Annex VI assigns Styrene H226 — flammable liquid and vapour. The flash point reported for it is 32 °C (89.6 °F) (HSDB).
Is Styrene a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Styrene. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health. IARC places it in Group 2A: probably carcinogenic to humans.
What is the exposure limit for Styrene?
The US occupational exposure limit reported for Styrene is 100.0 [ppm], Ceiling(OSHA) = 200 ppm(600 ppm is 5-min. peak in any 3 hrs.) (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 Styrene?
The boiling point reported for Styrene is 145.3 °C (293.5 °F) (HSDB).
What is the melting point of Styrene?
The melting point reported for Styrene is -30.65 °C (-23.2 °F) (HSDB).
How should Styrene be stored?
CLP Annex VI assigns Styrene the storage statement P403. Fireproof. Separated from incompatible materials. See Chemical Dangers. Cool. Keep in the dark. Store only if stabilized. Store in an area without drain or sewer access. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Styrene
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