FAQs about Styrene
General Questions about Styrene
What is styrene?
Styrene is a clear, colorless liquid that is an essential component of materials used to make thousands of everyday products. Its molecular formula is C8H8, meaning that it consists entirely of the elements carbon and hydrogen. Styrene is also known by several other names, including vinylbenzene, phenylethylene, cinnamene, Diarex HF 77, styrolene, and styrol.
Products made from styrene add convenience, value, and quality to daily life. 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 helps create remarkably strong, flexible, and light-weight products. Probably the most recognizable material is polystyrene, often encountered as expanded polystyrene foam (EPS). Other styrene-based materials include acrylonitrile-butadiene styrene (ABS), styrene-acrylonitrile (SAN), and styrene-butadiene rubber (SBR). Styrene is also used as a diluent and reactive cross-linker for thermoset polyester resin, which is combined with a reinforcement (such as glass fiber) to form composite materials such as fiberglass. The styrene used in these products comes from factories located all around the United States, and, indeed, around the world.
Styrene also occurs naturally and is an inherent component of tobacco smoke as well as many commonly-consumed foods and beverages, such as coffee, strawberries, and cinnamon. In fact, it was first extracted from the Turkish sweetgum tree (also called Levant styrax, after which styrene is named). Learn more at YouKnowStyrene.org.
How and where does the average person come in contact with styrene?
Most people are exposed to styrene every day in tiny amounts that may occur naturally in tobacco smoke and in food or which may be present in the air or consumer products. Styrene may also be recognized by its distinctive odor (described by some as floral or sweet at low concentrations) when using certain products such as latexes, paints, auto body patching putties, and polyester resin solutions.
Some people confuse styrene, which is a liquid, with polystyrene, which is a solid plastic made by chemically reacting, or polymerizing, individual styrene molecules into long polymer chains.
Styrene and polystyrene are different substances with different chemical and physical properties. Polystyrene is inert and has no styrene odor. Polystyrene often is used in applications where hygiene is important, such as health care and foodservice products. For more information on polystyrene products, visit the Plastics Foodservice Packaging Group (PFPG) website.
Does styrene cause cancer?
There are no strong or consistent indications that styrene causes any form of cancer in humans. Although some studies suggest that styrene-exposed workers may be at increased cancer risk, the human evidence for styrene carcinogenicity is inconclusive. Studies of general population environmental and consumer styrene exposure and cancer are less informative than the worker studies, but the available evidence does not suggest these low exposures are a concern. Extensive studies on mouse lung tumors show these are of low relevance to human cancer risk.
Is styrene harmful to people who may be exposed to it outside of the workplace?
Styrene is not harmful in the very small amounts that people may sometimes encounter in air, consumer products, or food. Someone working in an enclosed area with resin solutions containing styrene (patching the surface of a fiberglass boat, for example) may find the odor of styrene causes slight nausea or neurological symptoms. This is remedied by exposure to fresh air, and there is no lasting effect.
Learn more in the Science section of this website
There is negligible risk from exposures to styrene through everyday use of consumer products. However, two non-regulatory bodies, the International Agency for Research on Cancer and the U.S. National Toxicology Program Report on Carcinogens (RoC) have issued styrene classifications related to carcinogenicity.
Learn more in the Policy section of this website.
What happens to styrene released into the environment?
More than 96% of styrene released into the environment separates into the air, but styrene does not persist in the atmosphere due to photooxidation. Styrene emissions are not expected to contribute significantly to photochemical ozone formation (smog), and styrene emissions from industrial sources are subject to federal and state government regulation.
What are the benefits of using styrene instead of other alternative materials?
Styrenic materials have excellent performance characteristics, quality, low toxicity, and affordability. Styrene is so widely used because it has been substituted over the years for other materials to create improved products. For example, boats made from styrenic material are more structurally sound. Packaging is more sanitary and less costly. Automobiles feature lighter components, making them more fuel-efficient. And building insulation quality has greatly improved, helping to cut energy use, thereby reducing cost and global warming gas emissions.
What is the difference between styrene and styrenic compounds: (polystyrene, “styrofoam,” styrene butadiene rubber, etc.)
Many different chemical compounds and resins are made with or contain the building-block chemical styrene; all have different chemical and physical properties. Consumers should not make the assumption that because a compound or resin has “styrene” in its name or as part of its name that it is similar to the chemical styrene. Nor should they assume that because a compound or resin does not have “styrene” in its name that it is not made using styrene.
Is styrene used as a food additive?
While styrene occurs naturally in some foods, such as strawberries, cinnamon, beef, and beer, styrene is not used as a food additive.
Styrene in the workforce
Are workers exposed to styrene at greater risk for health concerns?
Occupational risks for most workplace exposures are within acceptable ranges. Only workers in the FRP industry using open-mold operations and not using respiratory protection have risk exceedances for styrene and should be considered for risk management measures.
The available data support safe exposures of 20 ppm (time-weighted, 8-hour average) for worker inhalation. Noise reduction measures are recommended where styrene is present to sustain levels below 85 decibels or dBA.
Does styrene cause hearing loss or damage?
Styrene is a demonstrated ototoxicant as evidenced by animal and human studies. The available human data indicates that ototoxicity results from short-term, high exposures. Prolonged exposures at lower concentrations with total higher cumulative styrene exposures do not appear to lead to hearing loss. Simultaneous exposure to noise and styrene appears to increase potential adverse effects. Noise protection is important for workers exposed to styrene.
Do styrene manufacturing plants emit an odor?
Styrene’s distinctive odor can be detected even when styrene is present at extremely low levels. People living near facilities that make or use styrene may sometimes notice an odor. Styrene odor can be detected at levels about 100-fold lower than the recommended worker protection limit. If concerns arise about such odors in your neighborhood, contacting the plant’s manager or the local health department may be appropriate.
What happens to styrene released into the environment?
Extensive research shows that styrene does not persist or accumulate in the atmosphere or in soils or surface waters. Studies also have shown that styrene is not likely to occur in drinking water. Additional information can be found in the Science section of this website
What is styrene’s impact on the U.S. economy?
In the U.S., the diversified styrene industry as a whole is an approximately $28 billion industry and has an annual industry payroll exceeding $4 billion. Every year the styrene industry contributes nearly $540 million to the U.S. trade balance and tax revenues of $7 billion annually. Learn more at YouKnowStyrene.org.
FAQs about Ethylbenzene
What is ethylbenzene?
Ethylbenzene is a clear, flammable liquid with an odor that is similar to gasoline. Ethylbenzene is commercially produced from benzene and ethylene in industrial plants, and a minor amount is isolated by purifying petroleum by-product streams. It is also present naturally in crude oil, some natural gas streams, and coal tar.
How are ethylbenzene and styrene related?
Styrene is a building block chemical that is used in the production of many different kinds of consumer products. Styrene is made from ethylbenzene.
Do consumer products contain ethylbenzene?
While ethylbenzene is a naturally-occurring component of automotive and other fuels, wood and tobacco smoke, it is primarily used to produce the chemical styrene. Styrene, which is used to make many industrial, consumer, and medical products, including many everyday household products, such as latex, paints, insulation, appliances, toys, food packaging, and safety products such as bicycle helmets, car seats, and flotation devices, may contain residual amounts of ethylbenzene from the production process.
How is the general public exposed to ethylbenzene?
The primary route of exposure to the general public to the very low levels of ethylbenzene found in the environment while at home, at school, outdoors, at work, and in a motor vehicle, is through the inhalation of ambient and indoor air, with the highest inhaled ethylbenzene concentrations occurring in smokers. Exposure to ethylbenzene also occurs from the ingestion of food stored and or served in food contact materials.
What about ethylbenzene and hydraulic fracturing (fracking)?
Nearly all ethylbenzene detected near petroleum extraction sites results from naturally occurring ethylbenzene which is present in crude petroleum and natural gas. In fact, according to a public website dedicated to fracking, <1% of oil wells report using ethylbenzene as a component of the chemicals and fluids used in the fracking process. For more information on ethylbenzene and fracking, SIRC suggests the following sources:
- FracFocus.org website
- “Chemicals Used In Hydraulic Fracturing,” United States House of Representatives Committee on Energy and Commence, Minority Staff Report, April 2011.