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Ethylene
Description: Ethylene (C.A.S. 74-85-1) is a colorless gas that is primarily used as an intermediate for chemical raw materials which in turn are used to manufacture a large variety of substances and products, including vinyl chloride, 1,2-dichloroethane, ethyl chloride, tetraethyl lead, and acetaldehyde. It is also used as a solvent, a refrigerant, a raw material for anesthetics, a plant growth regulator, and a medication. It is used in oxyethylene welding and cutting metals. As a compressed gas, it is used to initiate degreening and ripening of bananas, citrus fruits, honeydew melons, pears, and pineapples; on pineapples, it is applied before harvest to induce flowering. Chemical properties: Ethylene is a noncorrosive gas. It is explosive when mixed with oxygen. It has an unpleasantly sweet odor and a slightly sweet taste. It forms monoclinic prisms when it solidifies at -181 degrees C. It is soluble in water, acetone, alcohol, ether, and benzene. It burns with a luminous flame. Identification Health effects: When ethylene was used as an anesthesic, fatal accidents have occurred during ethylene anesthesia because the gas-oxygen mixtures are explosives; its use has declined since the 1970s. Exposure to ethylene anesthesia may cause hyperglycemia, nausea, vomiting, unpleasant aftertaste, cyanosis, high blood pressure, and diffusion hypoxia. Exposure to ethylene may cause unconsciousness and memory disturbances. Exposure occurs through inhalation, from leaks, spills, accidents, and cigarette smoke. Economics: In 1995, ethylene production in the United States was 46.97 billion pounds, which was the fourth largest volume of chemicals produced in the country. That total represented an increase from the chemical’s 1994 volume of 44.6 billion pounds. U.S. manufacturers of ethylene are Amoco Chemical Co., Alvin, TX; Lyondell Petrochemical Co., Channelview, TX; Chevron Chemical Co., Cedar Bayou, TX, and Port Arthur, TX; Dow Chemical USA, Freeport, TX, and Plaquemine, LA; DuPont, Orange, TX; Eastman Chemical Co., Longview, TX; Exxon Chemical Co., Baton Rouge, LA, and Baytown, TX; B.F. Goodrich Co., Calvert City, KY; Koch Refining Co., Corpus Christi, TX; Mobil Oil Co., Beaumont, TX, and Houston, TX; Occidental Petroleum Corp., Chocolate Bayou, TX, Corpus Christi, TX, and Lake Charles, LA; Sun Co., Brandenburg, KY, and Claymont, DE; Phillips Petroleum Co., Sweeny, TX; Quantum Chemical Co., Clinton, IA, Morris, IL, and Deer Park, TX; Rexene Corp., Odessa, TX; Shell Oil Co., Deer Park, TX, and Norco, LA; Texaco Chemical Co., Port Arthur, TX, and Port Neches, TX; Formosa Plastics Corp., Point Comfort, TX; Union Carbide Corp., Seadrift, TX, Taft, LA, and Texas City, TX; Javelina Gas Processing, Corpus Christi, TX; and Sweeney Olefins Limited Partnership, Sweeney, TX. Regulation: Ethylene is regulated under the Federal Insecticide, Fungicide, and Rodenticide Act, and the Emergency Planning and Community Right-to-Know Act. Under the Emergency Planning and Community Right-to-Know Act, releases of more than one pound of ethylene into the air, water, and land must be reported annually and entered into the Toxic Release Inventory (TRI). Facilities having a threshold quantity of 10000 pounds of ethylene are subject to the Risk Management Program Rule (RMP), Section 112r of the 1990 amendments to the Clean Air Act. The RMP treats this chemical as neutrally buoyant. Under some circumstances, it can behave as a dense gas upon release. 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 |