Toxicology of 1,3-butadiene, chloroprene, and isoprene

Abstract

The diene monomers 1,3-butadiene, chloroprene, and isoprene, shown in Fig. 1, are important building blocks used in the synthesis of polymers. These volatile organic compounds contribute significantly to the atmospheric burden of organic chemicals, appearing at low parts per billion (ppb) Fig. 1. Structures of butadiene, chloroprene, and isoprene. concentrations in ambient air near industrial sites where they are used. Occupational exposures to these dienes occur at higher air concentrations approaching or slightly exceeding the parts per million (ppm) threshold in facilities that produce or polymerize these monomers. Such exposures present significant continuing concern to occupational hygienists and epidemiologists in the quest to provide safe working conditions during production. These three chemicals, which differ chemically only by substitution of a hydrogen, chlorine, or methyl group at the 2-carbon of the molecule, provide interesting comparisons among their physical properties, occurrence, uses, and potential health effects. This review does not attempt comprehensive review of these chemicals, as that would fill many volumes. Search of the National Library of Medicine Medline database yielded more than 1,100, 700, and 130 citations, respectively, when butadiene, isoprene, and chloroprene were sought as keywords indexed from publications between 1966 and October 2005. © 2007 Springer.