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Benzene
Description: Benzene (C.A.S. 71-43-2) is produced naturally by volcanoes and forest fires, and is present in many plants and animals, but is also a major industrial chemical made from coal and oil. As a pure chemical, benzene is a clear, colorless liquid. It is used to make other intermediate chemicals and some types of plastics, liquid detergents, synthetic rubbers and fibers, and pesticides. It is used in plastic containers, adhesives, radios, toys, sporting goods, appliances, automobiles, tires, and textiles. Benzene has been used in the rotogravure printing industry, in shoe manufacturing, and chemical laboratories. It is also a component of motor vehicle gasoline. Emissions can be detected from carpet glue, textured carpet, and furniture wax. Chemical Properties: Benzene is a colorless, volatile, flammable liquid with an aromatic odor. It produces poisonous gas in fire; containers of benzene may explode in fire. The vapor is heavier than air and may travel a distance to cause a fire or explosion far from the source. It is slightly soluble in water and is miscible with alcohol, ether, acetone, carbon tetrachloride, carbon disulfide, and glacial acetic acid. It is incompatible or reactive with strong oxidizers, many fluorides and perchlorates, and nitric acid. Synonyms for benzene include (6) annulene, 1,3,5-cyclohexatriene, benceno (DOT Spanish), benzene (DOT French), benzin, benzine, benzol, benzole, benzolene, bicarburet of hydrogen, carbon oil, coal naphtha, cyclohexatriene, mineral naphtha, motor benzol, NCI-C55276, nitration benzene, phene, phenyl hydride, pyrobenzol, pyrobenzole, RCRA Waste Number U019, UN 1114, and [6]annulene. Identification: Health Effects: Benzene is a known carcinogen; exposure to it has been shown to cause leukemia. It is also believed to cause tumors in animals and possibly in humans. Major human exposures occur in gassing vehicles and as a result of vaporization of gas from car fuel tanks in garages, where the benzene seeps into attached homes. Other health effects of long-term exposure include damage to the blood-forming organs, enough to cause death (aplastic anemia), and drying and scaling of the skin. Benzene exposure is also associated with chromosomal damage. Exposure to very high concentrations of benzene can be fatal within minutes, with central nervous system depression and convulsions. Deaths from cardiac sensitization, cardiac arrhythmias, and comas have been reported after exposure to unknown concentrations. Other short-term health effects that may occur immediately or shortly after exposure to benzene include dizziness, lightheadedness, headache, vomiting, and irritation of the eyes, nose and throat. Exposure Values: Economics: U.S. manufacturers of benzene Amerada Hess Corp, Hq, 1185 Ave of the Americas, St Croix, Virgin Islands; American Petrofina Inc, Port Arthur, TX; Amoco Corp, Texas City, TX ; Aristech Chemical Corporation, Clairton, PA; Arochem International Inc, Penuelas, PR; Ashland Oil, Inc, Catlettsburg, KY; Atlantic Richfield Co, Channelview, TX; BP America, Inc, Lima, OH; Champlin Refining & Chemicals Inc, Corpus Christi, TX; Chevron Corp, Philadelphia, PA, Port Arthur, TX; Citgo Petroleum Corp, Lake Charles, LA; The Coastal Corp, Westville, NJ, Corpus Christi, TX; Crown Central Petroleum Corp, Pasadena, TX; Dow Chemical USA, Freeport, TX, Plaquemine, LA; Exxon Corp, Baton Rouge, LA, Bayton, TX; Hoechst Celanese Corp, Bayport, TX; Kerr-McGee Corp, Corpus Christi, TX; Koch Industries, Inc, Corpus Christi, TX; Mobil Corp, Beaumont, TX, Chalmette, LA; Occidental Petroleum Corporation, Chocolate Bayou, TX; Phillips Petroleum Company, Sweeny, TX, Guayama, PR; Salomon Inc, Houston, TX; Shell Oil Company, Deer Park, TX, Odessa, TX, Wood River, IL; Sun Company, Inc, Marcus Hook, PA, Toledo, OH, Tulsa, OK; Texaco Inc, Delaware City, DE; El Dorado, KS, Port Arthur, TX; Unocal Corp, Beaumont, TX, Chicago,IL; and USX Corporation, Texas City, TX. Regulation: Benzene releases into the air are regulated by OSHA and by EPA; releases into the water are regulated by EPA. Benzene is on EPA's Workplace Hazardous Substances List because it is regulated by OSHA, and is also one of the 100 most significant hazardous substances as determined by EPA and the Agency for Toxic Substances and Disease Registry under Superfund, which regulates benzene as a toxic waste. Benzene is classified by EPA as a hazardous substance under the Safe Drinking Water Act and a hazardous air pollutant under the Clean Air Act. The final OSHA Benzene standard in 1910.1028 applies to all occupational exposures to benzene except some subsegments of industry where exposures are consistently under the action level (i.e., distribution and sales of fuels, sealed containers and pipelines, coke production, oil and gas drilling and production, natural gas processing, and the percentage exclusion for liquid mixtures); for the excepted subsegments, the benzene limits in Table Z-2 apply (i.e., an 8-hour TWA of 10 ppm, an acceptable ceiling of 25 ppm, and 50 ppm for a maximum duration of 10 minutes as an acceptable maximum peak above the acceptable ceiling). Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986, releases of more than one pound of benzene into the air, water, and land must be reported annually and entered into the Toxic Release Inventory (TRI). National Overview of 1998 Toxics Release Inventory See EPA's Toxic Release Inventory. Notations: The NIOSH recommended exposure limits (RELs) are time-weighted average (TWA) concentrations for up to a 10-hour workday during a 40-hour workweek. A short-term exposure limit (STEL) is designated by "ST" preceding the value; unless noted otherwise, the STEL is a 15-minute TWA exposure that should not be exceeded at any time during a workday. A ceiling REL is designated by "C" preceding the value. Any substance that NIOSH considers to be a potential occupational carcinogen is designated by the notation "Ca." The OSHA permissible exposure limits (PEL) are found in Tables Z-1, Z-2, and Z-3 of the OSHA General Industry Air Contaminants Standard (29 CFR 1910.1000). Unless noted otherwise, PEL are TWA concentrations that must not be exceeded during any 8-hour workshift of a 40-hour workweek. A STEL is designated by "ST" preceding the value and is measured over a 15-minute period unless noted otherwise. OSHA ceiling concentrations (designated by "C" preceding the value) must not be exceeded during any part of the workday; if instantaneous monitoring is not feasible, the ceiling must be assessed as a 15-minute TWA exposure. In addition, there are a number of substances from Table Z-2 (e.g., beryllium, ethylene dibromide, etc.) that have PEL ceiling values that must not be exceeded except for specified excursions. For example, a "5-minute maximum peak in any 2 hours" means that a 5-minute exposure above the ceiling value, but never above the maximum peak, is allowed in any 2 hours during an 8-hour workday. Information Sources:
Originally published in Environment Writer by the National Safety Council. Reprinted with permission. Environment Writer Metcalf Institute for Marine and Environmental Reporting University of Rhode Island Graduate School of Oceanography Office of Marine Programs Narragansett, RI 02882 Tel: 401-874-6211; Fax: 401-874-6485 Disclaimer * Copyright 2002-2006 * All rights reserved. * University of Rhode Island |