Benzene - The Next Asbestos? - RAE Systems Inc - #1

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Benzene--The Next Asbestos? Monitor in g technologies to mitigate r isk and cr ea t e a safer and mor e compliant plant envir on m en t By Meg Godfrey, RAE Systems A graduate in mechanical engineering from the University of Texas at Austin, Meg Godfrey is the Product Marketing Manager for Portable Products for RAE Systems, Inc., (www.raesystems.com) of San Jose, California. She can be reached at mgodfrey@raesystems.com. The thr ea t of benzene The aromatic hydrocarbon benzene is almost everywhere. It is a component of gasoline, and it is an important industrial solvent and precursor in the production of drugs, plastics, synthetic rubber, and dyes. It is a natural constituent of crude oil, but it is usually synthesized from other compounds present in petroleum. It is found in high concentrations in cigarette smoke. Like asbestos, the use and handling of benzene has changed over the past several decades as its toxic properties have become better understood. As the understanding of the threat has developed, various sensing technologies and regulations have been used to provide better protection of people at higher risk of exposure. Histor y and uses Benzene was first discovered and isolated from coal tar in the 19th century. Prior to the 1920's, benzene was frequently used as an industrial solvent, especially for degreasing metal. As its toxicity became obvious, other solvents replaced benzene in applications that directly exposed the user to benzene. Today, benzene is made mostly from petroleum sources and ranks in the top 20 in production volume for chemicals produced in the United States. By far the largest use of benzene is an intermediate to make other chemicals. The most widely produced derivatives of benzene are styrene, which is used to make polymers and plastics, phenol for resins and adhesives (via cumene), and cyclohexane, which is used to manufacture Nylon. Smaller amounts of benzene are used to make some types of rubbers, lubricants, dyes, detergents, drugs, explosives and pesticides. As many as 238,000 people may be occupationally exposed to benzene in the United States. These industries include benzene production (petrochemicals, petroleum refining, and coke and coal chemical manufacturing), rubber tire manufacturing, and storage or transport of benzene and petroleum products containing benzene. Other workers who may be exposed to benzene due to their occupations include steel workers, printers, rubber workers, shoe makers, laboratory technicians, and gas station employees. Char a ct er ist ics and health effects Benzene is a colorless liquid with a sweet odor. Benzene evaporates into air very quickly, dissolves slightly in water, and is highly flammable. Most people can begin to smell benzene in air at 1.5 - 4.7 parts of benzene per million parts of air (ppm) and can begin to taste benzene in water at 0.5 - 4.5 ppm. Benzene's health hazards are well documented. It is a recognized carcinogen, developmental and reproductive toxicant. It is also suspected as a toxicant in cardiovascular, endocrine, gastrointestinal, immunological, neurological, and respiratory systems.