When it is linked together in long chains, or polymerised, styrene is used predominantly in the production of polystyrene plastics and resins, such as in insulation or in the fabrication of fibreglass boats; most styrene products contain a residue of unlinked styrene. Styrene is also used to make rubber, and as an intermediate in the synthesis of materials used for ion exchange resins and to produce copolymers such as styrene-acrylonitrile, acrylonitrile-butadiene-styrene, and styrene-butadiene rubber.
Substance name: Styrene (ethenylbenzene)
CASR number: 100-42-5
Molecular formula: C8H8
Synonyms: Ethenylbenzene, ethenyl benzene, cinnamene, cinnamenol, NCI-C02200, phenylethene, phenylethylene, styrene monomer, styrol, styrole, styrolene, vinylbenzol, and vinylbenzene
Pure styrene is a colourless to yellowish oily liquid that evaporates easily and has a sweet smell. It is often mixed with other substances that give it a sharp smell. It is flammable.
Specific Gravity: 0.905
Melting Point: -31 to -30.6°C
Boiling Point: 145-146°C
Vapour pressure: 4.3 mm Hg @ 15°C
9.5 mm Hg @ 30°C
10 mm Hg @ 35°C
Styrene dissolves in some liquids, but dissolves only slightly in water. It is soluble in alcohol, ether, acetone, and carbon disulfide; it is incompatible with oxidisers, catalysts for vinyl polymers, peroxides, strong acids, and aluminium chloride. Styrene is dangerous when exposed to flame, heat or oxidants; it reacts violently with chlorosulfonic acid, oleum, and alkali metal-graphite, and reacts vigorously with oxidising materials. It may polymerise if contaminated or subjected to heat; on decomposition, it emits acrid fumes. It usually contains an inhibitor such as tert-butylcatechol.
The National Pollutant Inventory (NPI) holds data for all sources of Styrene (ethenylbenzene) in Australia.
Styrene affects the central nervous and respiratory systems, including depression, concentration problems, muscle weakness, fatigue, unsteadiness, narcosis, defatting dermatitis, and nausea. Exposure may also irritate the nose, throat, and eyes, including severe eye injuries. The International Association for Research into Cancer (IARC) classifies styrene as 'possibly carcinogenic to humans (Group 2B)'.
Entering the body
By absorption into the blood through the lungs, stomach, skin or eyes. Populations with potentially high exposures to styrene include people working in various styrene industries, smokers, and those eating a high proportion of foods packaged in polystyrene.
Exposure to Styrene can be by breathing the vapours, contact with pure styrene or substances containing styrene or by eating or drinking foods containing or contaminated by styrene.
Workplace exposure standards
Safe Work Australia sets the workplace exposure standard for styrene through the workplace exposure standards for airborne contaminants:
- Maximum eight hour time weighted average (TWA): 50 parts per million (213 mg/m3)
- Maximum short term exposure limit (STEL): 100 parts per million (426 mg/m3)
These standards are only appropriate for use in workplaces and are not limited to any specific industry or operation. Make sure you understand how to interpret the standards before you use them.
Drinking water guidelines
The Australian Drinking Water Guidelines include the following guidelines for acceptable water quality:
- Maximum of 0.03 milligrams per litre of water for health purposes
- Maximum of 0.004 milligrams per litre of water for aesthetic considerations
Styrene is moderately toxic to aquatic organisms. Styrene is expected to have low toxicity towards terrestrial animals. Styrene contributes to the formation of photochemical smog due to indirect photochemical reactions.
Entering the environment
Styrene will be transported as a vapour in air, in water and in contaminated soils. Styrene has a slight tendency to bioaccumulate.
Where it ends up
Styrene is quickly broken down in the air, usually within one to two days; it evaporates from shallow soils and surface water. Styrene that remains in soil or water may be broken down by bacteria. Styrene Monomer is non-persistent in water, with a half-life of less than 2 days. About 99% of Styrene Monomer will eventually end up in air; about 0.85% will end up in water; the rest will end up in terrestrial soils and aquatic sediments.
No national guidelines.
Sources of emissions
Styrene will be emitted to air from industrial process that use or manufacture the material or where it is formed as a by-product.
Diffuse sources, and industry sources included in diffuse emissions data
Styrene is present in combustion products such as cigarette smoke.
Low levels of styrene occur naturally in a variety of foods, such as fruits, vegetables, nuts, beverages, and meats.
Styrene is present in car exhaust.
Products produced from styrene include packaging, electrical and thermal insulation, fibreglass, pipes, car parts, drinking cups and other food-use items, and carpet backing.
Sources used in preparing this information
- ChemFinder Searching (accessed, May, 1999)
- Environmental Chemicals Data and Information Network (accessed, May, 1999)
- Environmental Writer (accessed, May, 1999)
- International Association for Research into Cancer: Styrene (accessed, May, 1999)
- National Environment Protection Council (1998a), National Environment Protection Measure for the National Pollutant Inventory (accessed, May, 1999)
- New Jersey Dept of Health, Right to Know, TRIFacts (accessed, May, 1999)
- Technical Advisory Panel (1999), Final Report to the National Environment Protection Council.
- University of Cornell Material Safety Data Sheets (accessed, May, 1999)
- US EPA Chemical Summaries (accessed, May, 1999)
- US National Toxicology Program (accessed, May, 1999)
- USEPA Integrated risk Information System (accessed, May, 1999)
- Safe Work Australia, Workplace exposure standards for airborne contaminants, accessed February 2019.
- National Health and Medical Research Council (NHMRC), Australian Drinking Water Guidelines (2011) - Updated October 2017, accessed May 2018.