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Chloroform
Description: Chloroform (C.A.S. 67-66-3) is a colorless liquid with a sweet odor. It is used primarily in the production of chlorofluorocarbon (CFC)-22, and in the production of plastics, especially vinyl chloride. Its other uses are as an industrial solvent in the extraction and purification of some antibiotics, alkaloids, vitamins, and flavors; as a solvent for lacquers, floor polishes, artificial silk manufacture, resins, fats, greases, gums, waxes, adhesives, oils, and rubber; as an industrial solvent in photography and dry cleaning; as a heat transfer medium in fire extinguishers; and as an intermediate in the preparation of dyes and pesticides. Chloroform formulated with other ingredients is used to control screw worm in animals. Its use as an anesthetic has been largely discontinued. Chloroform is often produced during the chlorination of drinking water and thus is a common drinking water contaminant. Chemical Properties: Chloroform is a colorless, volatile, non-flammable liquid which is slightly water-soluble and is miscible with oils, ethanol, ether, and other organic solvents. It produces poisonous gas in a fire and is unstable when exposed to air, light, and/or heat, which cause it to break down to phosgene, hydrochloric acid, and chlorine. When heated to decomposition, chloroform emits toxic fumes of hydrochloric acid and other chlorinated compounds. Fire may also cause containers of it to explode. Violent reactions will occur if chloroform makes contact with strong caustics and chemically active metals such as aluminum, magnesium powder, sodium, or potassium. Synonyms for chloroform are methane trichloride; trichloromethane; chloroforme (DOT French); cloroformo (DOT Spanish); formyl trichloride; freon 20; HCC 20; methane, trichloro-; methenyl chloride; methenyl trichloride; methyl trichloride; NCI-C02686; NCI-CO2868; R 20; R 20 (refrigerant); R 20 (refrigerant); R-20; RCRA Waste Number U044; TCM; trichloroform; and UN 1888. Identification: Health Effects: Chloroform is a carcinogen. It is also believed to be a teratogen in animals, and possibly in humans. Other long-term health effects include damage to the liver, kidney, and nervous system, and drying and cracking of the skin. Alcohol consumption can increase the liver damage caused by chloroform. Exposure to chloroform, either through breathing or making contact with the skin, may cause several other short-term and long-term health effects. Immediately or shortly after exposure to chloroform, the heart may beat irregularly or stop. Exposure can also cause dizziness, lightheadedness, nausea, confusion, and headache. Contact with it can irritate skin, causing a rash or burning feeling. The liquid can cause severe eye burns. Exposure to the vapor can irritate the nose and throat. Higher levels of exposure can cause coma and death. Exposure Values: Economics: U.S. manufacturers of chloroform are Dow Chemical USA, Freeport, TX; Hanlin Group, Inc, Moundsville, WV; Occidental Petroleum Corporation, Belle, WV; and Vulcan Materials Company, Geismar, LA, Wichita, KS. Regulation: The Occupational Safety and Health Administration (OSHA) has issued permissible exposure limits for chloroform. EPA regulates chloroform under the Clean Water Act; Comprehensive Environmental Response, Compensation, and Liability Act; Federal Insecticide, Fungicide, and Rodenticide Act; Food, Drug and Cosmetic Act; Resource Conservation and Recovery Act; Safe Drinking Water Act; and Superfund Amendments and Reauthorization Act. Chloroform is a toxic pollutant of air and water. EPA has established water quality criteria for chloroform, effluent guidelines, rules for regulating hazardous spills, general threshold amounts, and requirements for handling and disposal of chloroform. Under Section 302 of the Emergency Planning and Community Right to Know Act of 1986, chloroform is listed as an Extremely Hazardous Substance and has a threshold planning quantity of 10,000 lbs. Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986, releases of more than one pound of chloroform into the air, water, and land must be reported annually and entered into the Toxic Release Inventory (TRI). Facilities having a threshold quantity of 20,000 lbs of chloroform are subject to the Risk Management Program Rule (RMP), Section 112r of the 1990 amendments to the Clean Air Act. Chloroform has a toxic endpoint of 0.49 mg/L. 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 |