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Tetrachloroethylene
Description: Tetrachloroethylene (C.A.S. 127-18-4) is a colorless liquid solvent with a sweet chloroform-like odor, widely used for dry cleaning and metal degreasing. It is also used in the production of other chemicals, mostly for chlorofluorocarbon CFC-113. The chemical is used in smaller quantities in rubber coatings, solvent soaps, printing inks, adhesives and glues, sealants, polishes, lubricants, and pesticides. Chemical and physical properties: Synonyms for tetrachloroethylene are 1,1,2,2-tetrachloro-ethylene; perchloroethylene; perc; carbon bichloride; carbon dichloride; ethylene -tetrachloride; per; perchlor; perchloethylene; and perk. It is nonflammable, and insoluble in water. Although it is a liquid at room temperature, some of the liquid can be expected to evaporate into the air, producing an ether-like odor. Evaporation increases as temperature increases. It is a non-combustible liquid, but if burned, will produce poisonous gases in a fire, including hydrogen chloride and phosgene. Identification: Health effects: Tetrachloroethylene may be a carcinogen in humans and may damage the developing fetus. Exposure to high concentrations of it in air, particularly in poorly ventilated areas, can cause dizziness, light-headedness, nausea, confusion, difficulty in speaking and walking, possibly unconsciousness, and death. Overexposure can cause the heart to beat irregularly or stop. Tetrachloroethylene can also damage the liver and kidneys enough to cause death. Breathing the vapor may irritate the lungs, causing coughing and/or shortness of breath. Higher exposure can cause a build-up of fluid in the lungs, which can cause death. Contact with the liquid can cause severe skin burns, and can cause eye burns. It may damage the liver and kidneys with high single exposures or lower repeated exposures. Long-term exposure can cause drying and cracking of the skin. Exposure to the vapor can irritate the eyes, nose, mouth, and throat. It is estimated that nearly 500,000 U.S. workers are at risk of exposure to tetrachloroethylene at over 20,000 dry-cleaning establishments and at a large number of other industries manufacturing or using the chemical. Populations at high risk of exposure to the chemical include those living in the vicinity of dry-cleaning operations, factories which emit tetrachloroethylene, and chemical waste dumps. Exposure Values: Economics: U.S. manufacturers of Tetrachloroethylene are: Dow Chemical USA, Midland, MI, Occidental Petroleum Corporation, Hq, Los Angeles, CA, PPG Industries, Inc, Pittsburgh, PA, and Vulcan Materials Company, Metal Division, Birmingham, AL. Regulation: The Occupational Safety and Health Administration issues permissible exposure limits for tetrachloroethylene; the Food and Drug Administration lists the chemical as a substance for use only as a component of adhesives. EPA Offices overseeing regulations and guidelines applicable to tetrachloroethylene include Air Quality Planning and Standards, under National Emissions Standards for Hazardous Air Pollutants; Water Regulations and Standards, under the National Pollutant Discharge Elimination System; Emergency and Remedial Response; Solid Waste; and Pesticide Programs. Under the Emergency Planning and Community Right-to-Know Act of 1986, releases of more than one pound of tetrachloroethylene into the air, water, or land must be reported annually and entered into the national Toxic Release Inventory (TRI) data base. National Overview of 1998 Toxic 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 |