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1,3-Butadiene
Description: 1,3-Butadiene (C.A.S. 106-99-0) is a colorless, noncorrosive gas with a mild aromatic or gasoline-like odor. It is used primarily as a chemical intermediate and polymer component in the manufacture of synthetic rubber. Its major uses are as a comonomer for styrene-butadiene rubber used to produce tires and tire products, hoses, and beltings (39%); in monomeric form, to produce tires and tire products, impact polystrenes, industrial hoses, belts, seals and gaskets (23%); in the production of adiponitrile (11%); as a chemical intermediate for styrene-butadiene latexes (9%); as a polychloroprene used to make Neoprene elastomers for non-tire and latex applications (7%); as a comonomer for nitrile rubber (3%), and for acrylonitrile-butadiene-styrene resins used to produce auto parts and appliances (5%); and other polymer or copolymer uses (2%). It is also used as a chemical intermediate for the fungicides Captan and Captofol, and in the manufacture of latex adhesives, various rubber products, nylon carpet backings, paper coatings, pipes, conduits, appliance and electrical equipment components, and luggage. Chemical properties: 1,3-Butadiene is both explosive and flammable because of its low flash point. Vapor may explode if ignited in an enclosed space. It is slightly soluble in water, more soluble in methanol and ethanol, and soluble in most common organic solvents such as acetone, ether, benzene, and cyclohexane. It readily polymerizes in the presence of sodium or oxygen. When heated, 1,3-butadiene emits acrid fumes, and explosive peroxides may form when it is exposed to air. Synonyms for 1,3-butadiene include 1-methylallene; alpha, gamma-butadiene; biethylene; bivinyl; bivinyl; erythrene; pyrrolylene; vinylethylene, butadienes, inhibited; alpha-gamma-butadiene; buta-1,3-diene; butadiene; butadiene-1,3; butadienes, stabilises (DOT French); butadienos, inhibidos (DOT Spanish); NCI-C50602; and vinyl ethylene. Identification: Health effects: 1,3-Butadiene is classified by the Occupational Safety and Health Administration (OSHA) as a "de minimis" carcinogen, meaning that the minimum amount of the chemical set by OSHA is considered to be carcinogenic. It is listed on EPA's Toxic Release Inventory (TRI) as a de minimis carcinogen. It is also defined as a substance which may reasonably be anticipated to be a carcinogen by the U.S. Department of Health and Human Services' National Toxicology Program's Fifth Annual Report on Carcinogens. Dermatitis and frostbite may result from exposure to liquid butadiene and evaporating gas. In high concentrations, the gas can act as an irritant, producing cough; and a narcotic producing fatigue, drowsiness, headache, vertigo, loss of consciousness, respiratory paralysis, and death. Chronic exposure may result in central nervous system disorders, diseases of the liver and biliary system, and tendencies toward hypertension, leukopenia, and decreased hemoglobin content in the blood. The primary routes of potential human exposure to 1,3- butadiene are inhalation, ingestion, and dermal contact with products containing 1,3-butadiene residues, ingestion of food containing residues as an indirect food additive, from living in the vicinity of plants producing or using the chemical. Exposure Values: Economics: U.S. manufacturers of 1, 3-butadiene are Amoco Corporation, Chocolate Bayou, TX; Atlantic Richfield Co., Channelview, TX; Dow Chemical USA, Freeport, TX; Exxon Corp, Baton Rouge, LA, Baytown, TX; Mobil Corp, Beaumont, TX; Occidental Petroleum Corporation, Chocolate Bayou, TX; Shell Oil Co, Norco, LA; Texaco Inc, Port Neches, TX; and Texas Olefins Co, Houston, TX. Regulation: EPA regulates 1,3-butadiene under the Clean Air Act and the Toxic Substances Control Act. The Food and Drug Administration regulates 1,3-butadiene as an indirect food additive. Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986, releases of more than one pound of 1,3-butadiene into the air, water, and land must be reported annually and entered into the Toxic Release Inventory (TRI). Toxics Release Inventory Information 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 |