Styrene [‘stī-,rēn] is a clear, colorless liquid that is synthesized for commercial use from petroleum and natural gas by-products. Styrene also occurs naturally in the environment and is an inherent component in small concentrations of many commonly-consumed foods and beverages, such as coffee, strawberries, and cinnamon.
Styrene is an essential component of materials used to make thousands of remarkably strong, flexible, and light-weight products for home, school, work, and play. These products range from convenient food containers and protective packaging materials to computer housings; consumer electronics; medical applications; components for automobiles, trucks, trains, boats, aircraft, and other means of transport; wind-energy parts; construction and water treatment products; building insulation; military personnel and vehicle armor; ballistic protection; fuel cells; gasoline and other storage tanks; protective sports gear, such as bicycle helmets; and many other important items. Styrene production and the manufacture of products derived from styrene represent an important part of the U.S. economy and these products enhance quality of life by providing improved energy efficiency, performance, and cost efficiencies.
Styrene: Chemical Identity & Physical Properties
General Information
| Chemical Name | Styrene |
| Synonyms | Cinnamene, ethenylbenzene, phenylethylene, styrol, vinylbenzene |
| Chemical formula | C8H8 |
| Chemical structure |  |
| Molecular weight | 104.15 g/mol |
| Color | Colorless to yellow |
| Odor | Sweet, aromatic (if pure) Sharp, penetrating, unpleasant (commercial grades) |
| Physical State | Oily liquid |
| Identification numbers | CAS Registry: 100 -42 -5 EINICS: 202 -851 -5 DOT/UN/NA/IMDG shipping: IMDG 3.3; UN 2055 |
Adapted from ATSDR Toxicological Profile for Styrene and the website of the European Styrene Producers Association.
Physical Properties
| Characteristic | Property |
| Melting point/freezing point | -30.6 °C (-23.1 °F) |
| Boiling point | 145.2 °C (293.4 °F) |
| Density at 20 °C | 0.9059 g/cm3 |
| Odor threshold: Water Air | 0.73 mg/L 0.1 ppm (0.43 mg/m3 ) |
| Solubility: Water at 20 °C Organic solvents | 300 mg/L (0.03% wt.vol.) Soluble in alcohol, ether, acetone, carbon disulfide |
| Partition coefficients: Log KOW Log KOC | 2.95 2.96 |
| Vapor density (air = 1) | 3.6 |
| Vapor pressure at 20 °C | 5 mmHG (5 mbar) |
| Henry’s law constant (at 25 °C) | 0.00261 atm-m3 /mol (calculated) |
| Autoignition temperature | 490 °C (914 °F) |
| Explosive limits in air | 0.9-6.8% vol. |
| Flashpoint | 31 °C (87 °F), closed cup 34.4 °C (93.9 °F), Tag open cup |
| Flammability limits | 0.9-1.1 (lower); 6.1-6.8 (higher) |
| Conversion factors | 1 mg/m3 =0.23 ppm 1 ppm=4.33 mg/m3 |
Adapted from ATSDR Toxicological Profile for Styrene and the website of the European Styrene Producers Association.
Click here for a printable download of styrene’s physical properties and chemical identity.
Additional valuable resources on styrene:
Styrene Science
SIRC’s comprehensive research program seeks to better understand the potential for styrene to affect human health.
Styrene Policy
The Styrene Information & Research Center (SIRC) monitors the regulatory activity on styrene.
Styrene FAQs
Learn more about styrene in the community, the environment, and the workplace.
