 |
Also see:
|
N-Nitrosodiphenylamine
Description: N-Nitrosodiphenylamine (C.A.S. 86-30-6) is not a naturally occurring substance; it is a man-made chemical that is no longer produced in the United States. It was used in rubber compounding as a retarder to prevent premature vulcanization of rubber compounds during mixing and other processing operations. It was generally used with sulfenamide accelerators in tire compounds and other mechanical goods. N-Nitrosodiphenylamine was also used as an intermediate in the manufacture of p-nitrosodiphenylamine, which was subsequently used to produced N-phenyl-p-phenylenediamine and other rubber- processing chemicals. U.S. manufacturers stopped producing N-nitrosodiphenylamine in the early 1980s because new and more efficient chemicals were found to replace it. It also had several undesirable side effects, which do not occur with replacement chemicals. Chemical properties: N-Nitrosodiphenylamine is a yellow or orange-brown solid with no odor. It is soluble in acetone, ethanol, benzene, and ethylene dichloride. Its flash point and flammability limits are unknown. It appears to be susceptible to biological degradation in soil and water, though the degradation rates may vary with local conditions. It appears to be susceptible to direct photodegradation in the presence of sunlight. Extended periods of persistence in soil or water may be possible if local microbial populations are very low or inactive, or if the concentration of the pollutants is high enough to be toxic to microbial populations. Synonyms for N-nitrosodiphenylamine are diphenylnitrosoamine, N-nitroso-n-phenylaniline, N-nitroso-n- phenylbenzenamine, N,n-diphenylnitrosoamine, nitrous diphenylamide, NDPA, and NDPhA. Identification: Health effects: There is little information available regarding effects of brief exposures to N-nitrosodiphenylamine on human health. It is not known if exposure to it by breathing or skin contact can affect the health of humans or animals, but because ingestion of N-nitrosodiphenylamine has been shown to have adverse health effects in animals, exposure of humans to the chemical should be minimized. Because it causes cancer in laboratory animals, it is assumed that exposures involve some risk for humans. Economics: N-nitrosodiphenylamine is no longer produced in the United States. The last year for which production volume figures are available is 1980, when 405,000 pounds were produced. U.S. manufacturers of N-nitrosodiphenylamine Uniroyal Chemical Company, Inc., Geismar, LA. Regulation: N-Nitrosodiphenylamine is listed by EPA as a low hazard ranking for carcinogenicity under Superfund. It is classified by EPA as a priority pollutant for toxic water discharges and a volatile organic compound. Under Section 313 of the Emergency Planning and Community Right to Know Act of 1986, releases of more than one pound of N-nitrosodiphenylamine 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 |