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Creosote
Description: Creosote is the name used for a variety of products that are mixtures of many chemicals; those products include wood creosote, coal tar creosote, coal tar, and coal tar pitch. Creosotes do not occur naturally in the environment; they are created by high-temperature treatment of beech and other woods (wood creosote) or coal (coal tar creosote), or from the resin of the creosote bush (creosote bush resin). Wood creosote (C.A.S. 8021-39-4) is a colorless to yellowish greasy liquid with a characteristic smoky odor and sharp burned taste. The major chemicals in wood creosote are phenol, cresols, and guaiacol. It has been used as a disinfectant, a laxative, and a cough treatment; it is rarely used today in the United States, but is still used as an expectorant and a laxative in Japan. Synonyms are Creosote, beechwood; beechwood creosote; creasote; creosote; creoeote beechwood; creosote,wood; liquid pitch oil; and wood creosote. Coal tar creosote (C.A.S. 8001-58-9) is the most common form of creosote in the workplace and at hazardous waste sites in the United States; it is referred to by EPA as creosote. It is a thick, oily liquid that is typically amber to black in color, and is a distillation product of coal tar. It has a burning, caustic taste. Coal tar creosote is the most widely used wood preservative in the United States, and is used as a wood preservative and water-proofing agent for log homes, railroad ties, telephone poles, marine pilings, and fence posts. It is also a restricted-use pesticide, and is used as an animal and bird repellant, insecticide, animal dip, fungicide, and a pharmaceutical agent for the treatment of psoriasis. About 300 chemicals have been identified in coal tar creosote, but there may be as many as 10,000 other chemicals in the mixture. Synonyms are creosote, [coal tar]; AWPA #1; brick oil; coal creosote; coal tar creosote; coal tar oil (DOT); creosote; creosote (wood); creosote oil; creosote P1; cresote, coal tar, creosote, from coal tar; creosotum; cresylic creosote; dead oil; heavy oil; liquid pitch oil; naphthalene oil; preserv-o-sote; RCRA Waste number U051; sakresote 100; tar oil; UN 1136 (DOT); and wash oil. Coal tar (C.A.S. 8007-45-2) and coal tar pitch (CAS #67996-93-2) are the by-products of the high-temperature treatment of coal to make coke or natural gas; they are usually thick, black or dark brown liquids or semi-solids with a naphthalene-like odor. Coal tar has a sharp, burning taste. Coal tar products are ingredients in medicines used to treat skin diseases such as psoriasis; they are also used as animal and bird repellants, insecticides, animal dips, and fungicides. Synonyms are tars, liquid; alquitranes, liuidos (DOT Spanish); BR 45; brown coal, tar; brown-coal, lignit tar; coal tar; coal tar extract; coal tar ointment; coal tar, brown; coal, brown, tar; coke-oven tar; coking tar; estar; estar (skin treatment); and EX 1500. Coal tar creosotes, coal tar, and coal tar pitch are similar in composition; the major chemicals in them that can cause harmful health effects are polycyclic aromatic hydrocarbons, phenol, and cresols. Chemical properties: Creosotes and coal tars are complex mixtures of variable composition containing primarily condensed aromatic ring compounds or phenols; therefore, it is not possible to represent the chemical formula and structure for these materials. Wood creosote is relatively soluble in water; it is miscible with alcohol, ether, and fixed or volatile oils. Coal tar creosote is easily set on fire and contains some components that dissolve in water and some that do not. It is miscible with alcohol, ether, and fixed or volatile oils. Coal tar creosote components dissolved into the water move through the soil to eventually reach and enter groundwater, where they may persist; once in the water, biodegradation may take months. Biodegradation in soil can take months for some components of coal tar creosote, or much longer for others. Coal tar is slightly soluble in water; it mostly dissolves in benzene; it partially dissolves in alcohol, ether, chloroform, acetone, and pet. ether. Synonyms for coal tar are crude coal tar, and pixalbol. Coal car pitch is incompatible with strong oxidizers; other properties vary depending upon the specific compound. Identification: Identification: Health effects: The International Agency for Research on Cancer has determined that coal tar creosote is probably carcinogenic to humans. EPA has determined that coal tar creosote is probably a human carcinogen, and that coal tar pitch is a human carcinogen; it classified coal tar creosote as a carcinogen in the 1992 Toxic Release Inventory (TRI). Skin cancer and cancer of the scrotum have resulted from long exposure to low levels of these chemical mixtures, especially through direct contact with skin during wood treatment or manufacture of coal tar creosote-treated products, or in coke or natural gas factories. Cancer of the scrotum in chimney sweeps has been associated particularly with prolonged skin exposure to soot and coal tar creosote. Eating food or drinking water contaminated with a high level of creosotes may cause a burning in the mouth and throat, as well as stomach pains. Brief exposure to large amounts of coal tar creosote may result in a rash or severe irritation of the skin, chemical burns of the surfaces of the eye, convulsions, mental confusion, kidney or liver problems, unconsciousness, or even death. Longer exposure to lower levels of coal tar creosote, coal tar, or coal tar pitch by direct contact with skin or by exposure to the vapors from these mixtures can also result in sun sensitivity and cause damage to skin, such as reddening, blistering, or peeling. Longer exposures to the vapors of the creosotes, coal tar, or coal tar pitch can also cause irritation of the respiratory tract. Economics: Creosote, Wood is not produced commercially in the U.S. NOT PRODUCED COMMERCIALLY IN USA Creosote in coal tar solution was produced in 1992 by Allied Signal, Inc., Engineered Materials Sector, Morristown, NJ; Aristech Chemical Corp., Pittsburgh, PA; Coopers Creek Chemical Corp., Conshohocken, PA; Koppers Industries, Inc., Pittsburgh, PA; and Reilly Industries, Inc., Indianapolis, IN. Regulation: Coal tar creosote releases into the air are regulated by the Occupational Safety and Health Administration (OSHA); permissible exposure limit, time-weighted average, is .2mg/m3; they are also regulated by EPA’s Office of Air and Radiation. Coal tar creosote is also regulated by EPA’s Offices of Emergency and Remedial Response, Chemical Emergency Preparedness and Prevention, Solid Waste, and Pesticide Registration Standards. Coal tar creosote is subject to these environmental laws: Comprehensive Environmental Response, Compensation, and Liability Act; Federal Insecticide, Fungicide, and Rodenticide Act; and Resource Conservation and Recovery Act. 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 |