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Hexachlorocyclopentadiene (HCCPD)
Description: Hexachlorocyclopentadiene (HCCPD) (C.A.S. 77-47-4) is a light, lemon-yellow liquid with a sharp, musty odor. It is a manufactured chemical that does not occur naturally in the environment. It is used to make a group of related pesticides: aldrin, chlordane, dieldrin, endosulfan, endrin, heptachlor, isodrin, mirex, and pentac. Only endosulfan and pentac are currently registered for use in the United States. HCCPD is also used to make flame retardants, resins that won’t burn, shock-proof and unbreakable plastics, acids, esters, ketones, fluorocarbons, and dyes. Chemical properties: Hexachlorocyclopentadiene is a highly volatile, reactive, and corrosive liquid. It easily turns from a liquid to a vapor when exposed to air. Its vapor looks like a blue haze. It is slightly soluble in water, and will react slowly with water to form hydrochloric acid. It is miscible in acetone, carbon tetrachloride, methanol, and hexane. Its melting point is -9 degrees C, and its boiling point is 239 degrees C. Synonyms are 1,3-cyclopentadine, percyclopentadiene, perchlorocyclopentadiene, hexachloropentadiene, and hex. Identification: Health effects: Exposure to hexachlorocyclopentadiene can cause sore throat, shortness of breath, nausea, abdominal cramps, chest discomfort, burning eyes, skin irritation, headaches, and irritation to the kidneys and liver. Exposure Values:
Economics: The sole U.S. manufacturer of hexachlorocyclopentadiene is Velsicol Chemical Corp., Memphis, TN. Production has decreased from the 1970s because of the regulatory restrictions on the use of many of the organochlorine pesticides using HCCPD as a chemical intermediate. Regulation: Under Section 302 of the Emergency Planning and Community Right-to-Know Act of 1986, Hexachlorocyclopentadiene is listed as an extremely hazardous substance, and has a threshold planning quantity of 100 pounds. Under Section 313 of the Emergency Planning and Community Right-to-Know Act, releases of more than one pound of hexachlorocyclopentadiene into the air, water, and land must be reported annually and entered into the Toxics 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 |