Styrene (ethenylbenzene)

Synonyms

cinnamene, cinnamenol, Ethenylbenzene, ethenyl benzene, NCI-C02200, phenylethene, phenylethylene, styrene monomer, styrol, styrole, styrolene, vinylbenzol, and vinylbenzene

Styrene

What is Styrene?

Styrene is a clear colourless solvent that is derived from natural gas and petroleum products. It is primarily synthetic but does occur naturally. The fibreglass reinforced plastics industry uses Styrene widely. In this industry most polyester resins that are used (approximately 40-60%) contain substantial amounts of styrene. Styrene can enter the body through the lungs or the skin and is considered a major hazard. The health of workers over both the short and long term can be potentially damaged by exposure to styrene.

Physical properties of styrene:

• Air is lighter that Styrene vapour. At concentrations normally encountered in the workplace, the air and styrene mixture is not significantly heavier than clean air.
• Styrene can be smelled at very low concentrations. Prolonged exposure to styrene reduces a person’s ability to smell it.
• Styrene evaporates more rapidly at high temperatures (e.g. the evaporation rate at 30° C is twice that at 20 ° C).

Is Styrene dangerous?

Styrene is a volatile, highly flammable compound. All resins containing liquid styrene, styrene and styrene vapours are ighly flammable. All sources of ignition must be removed from areas where these materials are used or stored (of course no smoking is permitted).  Safety measures may also include the use of non-sparking ventilation fans and electrical equipment. Reference should be made to The Occupational Health and Safety Regulation 2001, under the Occupational Health and Safety Act 2000, as these cover the storage of flammable liquid¹.

As styrene vapour is heavier than air, it may travel some distance to an ignition source and
flash back.

• Resins and liquid styrene should be stored in a cool, dry, well ventilated area, out of direct sunlight and in a part of the workplace separate from the production area.
• Resins and liquid styrene should be stored away from possible sources of ignition.
• Containers containing styrene compounds must be adequately labeled and tightly closed when not in use.

How is Styrene Produced?

Styrene is produced by the dehydrogenation of ethylbenzene in the presence of polymerization inhibitors.

What products may contain Styrene?

When it is linked together in long chains, or polymerised, styrene is used:

• in the production of :

• polystyrene plastics and resins, e.g. insulation or in the fabrication of fibreglass boats,
• as a solvent for synthetic rubber and resins,
• the manufacturing of synthetic rubber,
• in the production of propylene oxide.

Products produced from styrene include car parts, carpet backing, drinking cups and other food-use items, electrical and thermal insulation packaging, fibreglass, and pipes.

Sources of emissions

Styrene is emitted to air from:

• Industrial processes that use or manufacture the material or where it is formed as a by-product.
• Cigarette smoke.
• car exhaust

How might I be exposed to Styrene?

Exposure to Styrene can be by contact with pure styrene or substances containing styrene, breathing the vapours, or by eating or drinking foods containing or contaminated by styrene. People working in various styrene industries and smokers can have potentially high exposures to styrene.

How might Styrene enter my body?

• By absorption into the blood through the lungs, stomach, skin or eyes.
• Styrene liquid is soluble in body fat and can be absorbed through the skin; however, styrene present in polyester resin is not easily absorbed through the skin.
• Inhalation is therefore the major route of exposure.

How might exposure to Styrene affect my health?

Short Term Health Effects of Exposure to Styrene Vapours

• Irritation of eyes and mucous membranes.
• Dizziness, headache and fatigue
• Slower reaction times, reduced manual dexterity, and impaired co-ordination and balance
• Styrene liquid defats the skin and can cause dermatitis.
• Styrene liquid can cause mild to severe irritation of the eyes if splashing occurs.

Long Term Health Effects of Exposure to Styrene Vapours

• Repeated exposure to styrene vapours can have an effect on the central nervous system.
• The International Association for Research into Cancer (IARC) classifies styrene as 'possibly carcinogenic to humans (Group 2B)'.

What is the airborne exposure limit for Styrene Vapour?

Australia:

The Hazardous Substance Information System (HSIS) supplied by the Office of the Australian Safety and Compensation Council provides an eight-hour time weighted average (TWA) exposure limit of 213mg/m3 (50ppm) and short term exposure limit (STEL) of 426mg/m3 (100ppm) for the styrene monomer.

U.S.A:

In May 1997, The American Conference of Governmental Industrial Hygienists (ACGIH) established a 20ppm threshold limit value (TLV) for styrene in place of its existing 50ppm TLV guidance and a STEL of 40ppm.
The Occupational Safety and Health Administration (OSHA) have set a permissible exposure limit (PEL) for Styrene for general industry of 100ppm (for an 8-hour workday, 40-hour work week). The National Institute for Occupational Safety and Health (NIOSH) has a Recommended Exposure Limit (REL): of 215 mg/m3 TWA (50ppm) and 425 mg/m3 STEL (100ppm)

How can exposure to Styrene be monitored?

Atmospheric monitoring

• Should be carried out initially to determine workers’ exposure; and
• Subsequently if changes are introduced in the workplace likely to affect the level of styrene vapour.

Any measurements taken need to be representative of environmental conditions (especially ambient temperature) and changes in these conditions may require further monitoring to be carried out.

What does Atmospheric monitoring of Styrene involve?

Atmospheric monitoring involves measuring the concentration of styrene vapour either in:

• A worker’s breathing zone (personal samples); or
• At selected points in the factory (static samples).

Atmospheric monitoring can be used to determine:

• The extent of worker exposure and if any control measures are needed;
• The effectiveness of existing control measures (if any); and
• The effect of any changes made in the workplace (such as new control measures).
                 
There is a range of atmospheric monitoring devices available, including Absorbent tubes, Passive devices and Detector tubes.
Monitoring should be carried out by a person with appropriate training.

The Assessment of the Material Safety Data Sheets (MSDS)
In many cases the first step in planning an Occupational Hygiene Program is to assess the Material Safety Data Sheets (MSDS) for all the materials used by an organization, in addition to that of the chemical under investigation, Styrene.
In planning the program, GETEX hygienists must take into account any additive effects of a combination of materials (refer to synergistic effects above), and may also take into account a different time of exposure, for example, a 10 hour working day.

GETEX can help you instigate monitoring and/or devise a site management plan to control your site’s emissions.

The staff at GETEX has many years of experience in airborne hazardous material risk assessments including many projects involving the monitoring and management of VOCs including Styrene, Xylene, Glutaraldehydes and Formaldehyde. GETEX are ready to recommend & implement cost-effective monitoring programs in any part of Australia and overseas. Together with the administrative assistance and monitoring GETEX can recommend appropriate engineering controls and Personal Respirable Protective Equipment.

Why Choose GETEX?

• Trained Consultants with many years of experience across a broad range of occupational air quality services
• Trained Consultants employed by Getex are members of Australian Institute of Occupational Hygienists, Inc (AIOH)
• GETEX offers specialist occupational hygiene advice, 24 hours/7 days a week.
• GETEX carries full professional indemnity insurance.

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¹ In 2003 a review of the regulation of dangerous goods led to major reform. The regulation of the storage and handling of most classes of dangerous goods now come within the Occupational Health and Safety Regulation 2001, under the Occupational Health and Safety Act 2000. Explosives come under the Explosives Act 2003 and the Explosives Regulation 2005. The previous legislation, the Dangerous Goods Act 1975 and the Dangerous Goods (General) Regulation 1999, has been repealed.

The effect of these reforms was to place dangerous goods within a risk management framework, consistent with all other types of hazards found within workplaces. The Code of practice for the storage and handling of dangerous goods 2005 provides advice on applying this risk management framework to dangerous goods. These principles are extended to include aspects of public safety.
The changes are based upon the National Standard for the Storage and Handling of Workplace Dangerous Goods, produced by the National Occupational Health and Safety Commission in 2001.

The following legislation is in place: OHS Amendment (Dangerous Goods) Act 2003 and the supporting OHS Amendment (Dangerous Goods) Regulation 2005. These changes have been incorporated into Chapter 6A of the OHS Regulation 2001. Explosives Act 2003 and the supporting Explosives Regulation 2005

Note - the storage and handling of combustible liquids (as defined by Australian Standard 1940: 2004) are also regulated under this legislation.