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Styrene

Vinylbenzene, Ethenylbenzene, Styropor, Cinnamene

SPRI Emission Reporting Threshold
100 Kg/yr Pollutant Emissions to Air
Disclaimer
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Under normal conditions, Styrene is a colourless or pale yellow oily liquid. At low concentrations it has a sweet smell, but this can become unpleasant at high concentrations. Styrene evaporates fairly easily at room temperature and boils at 145 degrees celsius. When heated, it breaks down to give acrid fumes. Styrene is flammable and may react violently with some reagents. It may also react with itself when exposed to light. Styrene does not dissolve well in water, but mixes well with organic (carbon-containing) solvents. Styrene is one of a group of substances known as the volatile organic compounds (VOCs).
What is it used for?
Large quantities of Styrene are produced to make a variety of important chemical products. The most common of these is the widely used plastic "polystyrene". Other products include other types of plastics, synthetic rubbers, resins, fibreglass, insulation materials and food packaging.
Where does it come from?
Releases of Styrene may occur from industry producing or using it. It may also be released when products containing it are used or disposed of. Trace amounts of Styrene are present in cigarette smoke and vehicle exhaust fumes. Small amounts are found naturally in a variety of foods (fruits, vegetables, nuts and meat) and in natural gums and rubbers.
How might it affect the environment?
Exposure to high levels of Styrene may have moderately toxic effects to wildlife, particularly aquatic organisms. At levels normally found in the environment it is unlikely to cause significant harm. From surface waters or soils it evaporates fairly easily into the atmosphere, where it is broken down within a few days. That which remains in soils or waters is broken down within days by bacteria. Some seepage to groundwaters may occur where Styrene may persist for weeks or months. However, this is minimal as it is quickly broken down in or evaporated from soils and surface waters. Styrene does not accumulate in the environment. As a VOC, Styrene may be involved in the formation of ground level ozone, which can damage crops and materials. It is not considered likely that Styrene pollution has any effects on the global environment.
How might exposure to it affect human health?
Styrene enters the body mainly by inhalation of air containing styrene vapours, but can also enter by ingestion of contaminated water or food or by dermal contact with styrene or substances containing styrene. Inhalation of air containing styrene can affect the central nervous systems and cause symptoms including depression, headache, concentration problems, fatigue, nausea and drowsiness, irritation of the eyes, nose and throat and chemical pneumonitis. There is little information on the effects caused by the ingestion of styrene however some effects may be similar to those for inhalation. Dermal contact with styrene may result in skin irritation. The International Agency for Research on Cancer has designated styrene as a possible carcinogen However, exposure to styrene at normal background levels is unlikely to have any adverse effect on human health.
What steps are being taken to limit the potential impacts?
Releases of Styrene are controlled through the UK Pollution, Prevention and Control (PPC) Regulations. As a VOC, levels of Styrene in air are also controlled through the UK National Air Quality Strategy. European Directives regulating levels of Styrene include that which evaluates and controls the risks of substances known to be in the environment (793/93) and the Solvents Directive (99/13/EC). The main international legislation regulating levels of VOCs such as Styrene is the UN/ECE Convention on Long-Range Transboundary Air Pollution and the Basel Convention on the transboundary movement and disposal of hazardous wastes.