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2,4-Dinitrotoluene and 2,6-Dinitrotoluene
Description: 2,4-Dinitrotoluene (C.A.S. 121-14-2) and 2,6-dinitrotoluene (C.A.S. 606-20-2) are two of the six forms of the chemical called dinitrotoluene (DNT). They are pale yellow crystalline solids. There are no natural sources of DNT, which is usually manufactured by mixing toluene with nitric acid in the presence of concentrated sulfuric acid. This reaction produces a mixture which consists of approximately 80% of the 2,4-isomer and 20% of the 2,6- isomer. Also produced are small quantities of other DNT isomers. Small concentrations of DNT isomers also occur as by-products in the production of trinitrotoluene (TNT). 2,4-DNT and 2,6-DNT are used primarily as intermediates in the production of flexible polyurethane foams used in the bedding and furniture industry. DNT is also used in the production of munitions and explosives, for which DNT is a gelatinizing and waterproofing agent. It is also used as an intermediate in the manufacture of dyes, and as a purified form, in smokeless gunpowders. DNT has been detected in the soil, surface water, and groundwater of hazardous waste sites that contain buried munitions wastes. Chemical properties: 2,4-DNT is a highly reactive chemical and is a dangerous explosion hazard. It is combustible and may burn, but does not readily ignite. Poisonous gas is produced in a fire in which 2,4-DNT is burning. It is slightly soluble in water and soluble in alcohol ether, acetone, or benzene. 2,6-DNT is soluble in alcohol. DNT does not have a tendency to evaporate and is generally detected in the air only in manufacturing facilities. DNT may be released to or transported in the air as dusts, aerosols, and other suspended particles. There is little tendency for DNT to persist in the environment because it is decomposed by sunlight and by bacteria. Synonyms for 2,4-DNT are benzene, 1-methyl-2, 4-dinitro-; and 2,4-dinitrotoluol. Synonyms for 2,6-DNT are benzene,2-methyl-1,3- dinitro-; and 2,6-dinitrotoluol. Identification: Identification: Health effects: Heart disease has been observed in workers exposed to 2,4 or 2,6-DNT. There is some evidence that 2,4- and 2,6-DNT affect the nervous system and the blood of exposed workers. There is also one study showing that male workers exposed to 2,4- and 2,6-DNT had reduced levels of sperm, but later studies did not confirm the finding. Both 2,4-DNT and 2,6-DNT cause liver cancer in animals and may be human carcinogens. They can damage the human liver. Contact with molten 2,4-DNT or its hot fumes can cause severe skin and eye burns. Permanent eye damage may result. Exposure can interfere with the ability of the blood to carry oxygen, causing symptoms of weakness, dizziness, headaches, and blue coloration of the lips and nose. Higher exposure can cause nausea, vomiting, and fatigue, followed by shortness of breath, rapid or irregular heartbeat, unconsciousness, and death. The onset of these symptoms may be delayed for several hours after exposure. Repeated or prolonged exposures may cause low blood count (anemia). Economics: U.S. manufacturer of 2,4-dinitrotoluene is Du Pont Company, Deepwater, NJ. U.S. manufacturers of 2,6-dinitrotoluene are Air Products and Chemicals, Inc, Pasadena, TX; Miles, Inc, Baytown, TX, New Martinsville, WV; ICI Americas, Inc, Agricultural Chemicals Division, Polyurethane Group, Wilmington, DE; Rubicon, Inc, Gelsmer, LA. Regulation: The Occupational Safety and Health Administration (OSHA) has established permissible exposure limits for DNT. EPA offices regulating DNT are Water Regulations and Standards, Emergency and Remedial Response, and Solid Waste. Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986 releases of more than one pound of DNT into the air, water, and land must be reported annually and entered into the Toxic Release Inventory (TRI). 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 |