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Styrene (C6H5CH=CH2 or C8H8) Chemical Backgrounder

Description:

Pure styrene (C.A.S. 100-42-5) is a colorless liquid that evaporates easily and has a sweet smell. It often contains other chemicals that give it a sharp, unpleasant smell. When it is linked together in long chains, or polystyrene, styrene is used predominantly in the production of polystyrene plastics and resins, such as in insulation or in the fabrication of fiberglass 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. Products produced from styrene include packaging, electrical and thermal insulation, fiberglass, pipes, automobile parts, drinking cups and other food-use items, and carpet backing. Styrene is also present in combustion products such as cigarette smoke and automobile exhaust. Low levels of styrene occur naturally in a variety of foods, such as fruits, vegetables, nuts, beverages, and meats.

Chemical properties:

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 oxidizers, catalysts for vinyl polymers, peroxides, strong acids, and aluminum 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 oxidizing materials. It may polymerize if contaminated or subjected to heat; on decomposition, it emits acrid fumes. It usually contains an inhibitor such as tert-butylcatechol. 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.

Synonyms for styrene are ethenyl benzene, cinnamene, cinnamenol, NCI-C02200, phenylethene, phenylethylene, styrene monomer, styrol, vinylbenzol, and vinylbenzene.

Health effects:

Styrene is classified in EPA’s Toxic Release Inventory (TRI) as a carcinogen. Exposure can be through inhalation, ingestion, or skin or eye contact. The most common health effects from exposure to styrene affect 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 and lachrymation. 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.

Economics:

Styrene has been manufactured in the United States since 1938. U.S. production in 1992 was approximately 11.913 billion pounds. U.S. producers of styrene in 1992 were Amoco Chemical Company, Chemical & Specialty Products Group, Texas City, TX (800 million pounds); ARCO Chemical Company, Channelview, TX (2.525 billion pounds), and Monaca, PA (220 million pounds); Chevron Chemica; Company, Aromatics and Derivatives Division, St. James, LA (1.525 billion pounds); Cos-Mar, Inc., Carville, LA (1.9 billion pounds); Dow Chemical U.S.A., Freeport, TX (1.42 billion pounds); Huntsman Chemical Corporation, Bayport, TX (1.25 billion pounds); Rexane Corporation, Odessa, TX (320 million pounds); Sterling Chemicals, Inc., Texas City, TX (1.6 billion pounds); and Westlake Styrene Corporation, Sulphur, LA (353 million pounds).

Regulation:

OSHA has issued permissible exposure limits for styrene of 50 ppm (215 mg/m3) for time-weighted average, and 100 ppm (425 mg/m3) for short-term exposure limit. EPA offices regulating styrene are Water Regulations and Standards, Emergency and Remedial Response, Solid Waste, and Toxic Substances. The Food and Drug Administration regulates styrene as a food additive-synthetic flavoring substance, as an indirect food additive, as a component of polymers in paper in contact with dry food, and with a residual styrene monomer limit in polystyrene intended for use in contact with food.

Under the 1986 Emergency Planning and Community Right-to-Know Act, releases of more than one pound of styrene into the air, water, or land must be reported annually and entered into the TRI.

In 1990, 31,909,826 pounds of styrene were released by 1,423 facilities; those releases ranked 24th of the TRI's 322 chemicals. Of those releases, 13,472,563 pounds were fugitive or nonpoint air emissions; 18,204,101 pounds were stack or point air emissions; 37,371 pounds were surface water discharges; 29,045 pounds were released by underground injection; and 166,746 pounds were released to land.

The ten facilities releasing the largest amounts of styrene in 1990 were Ameripol Synpol Corp., TX, 971,900 pounds; GE Chemicals Inc., WV, 840,000 pounds; Polydyne Inc., WI, 489,848 pounds; Goodyear Tire & Rubber Co., TX, 472,150 pounds; Monsanto Co., IO, 457,016 pounds; GE Chemicals Inc., IL, 453,863 pounds; Lasco Bathware, MI, 422,962 pounds; Hytec Inc., WA, 325,200 pounds; Dynagen Inc., TX, 313,700 Pounds; and BP Chemicals Inc., CA, 310,739 pounds.

The five states in which the largest amounts of styrene were released in 1990 were TX, 4,016,681 pounds; CA, 2,416,070 pounds; IN, 2,416,018 pounds; OH, 2,296,519 pounds; and FL, 2,030,977 pounds.

For futher information:

Chemical Backgrounders - Styrene

Styrene Problem

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