Vinyl bromide (Bromoethylene)

Vinyl bromide is produced by the addition of hydrogen bromide to acetylene or by dehydrohalogenation of dibromoethane [1]. Its primary industrial use is as a monomer in copolymers with vinyl chloride, acrylonitrile, and other monomers to produce flame-retardant textiles and plastics [2]. The presence of bromine in the polymer backbone enhances fire resistance, making vinyl bromide copolymers useful in upholstery, children's sleepwear, and electrical cable insulation [1]. Structurally analogous to vinyl chloride — both are vinyl halides with adjacent carbon=carbon double bonds and halogen atoms — vinyl bromide was reasonably expected to share vinyl chloride's mutagenic properties [2].

Occupational inhalation in vinyl bromide monomer production and polymerization operations [1]. Workers in flame-retardant textile manufacturing using vinyl bromide copolymers [2]. Community exposure near vinyl bromide production facilities is possible but typically low [1].

Vinyl bromide undergoes CYP2E1-mediated epoxidation to vinyl bromide epoxide — an extremely reactive electrophile that forms DNA adducts at guanine and adenine, identical in mechanism to vinyl chloride carcinogenesis [1]. Liver angiosarcomas and hepatocellular carcinomas were induced in rats in NCI bioassay studies [2]. EPA classifies vinyl bromide as a B2 probable human carcinogen; IARC Group 2A [1].

Workers in vinyl bromide monomer synthesis and flame-retardant polymer production [1].

1. Occupational: local exhaust ventilation, continuous air monitoring, and biological monitoring programs [1]. 2. Enclosed polymerization systems to prevent monomer release [2].