In the past, chlorobenzene was used as an intermediate in phenol and DDT production. Only one pesticide in Canada under temporary registration contains chlorobenzene. Chlorobenzene enters the environment from industrial and municipal discharges. Another potential source is the formation and emission of chlorobenzene as a product of incomplete combustion in waste incinerators.
Occupational exposure occurs primarily through breathing the chemical.
Personnel engaged in the production and handling of chlorobenzene would be at greatest risk. Chlorobenzene is slightly persistent in water, with a half-life of between 2 to 20 days. Chlorobenzene is a flammable liquid and a fire hazard. It is unreactive towards water and decomposes only at high temperatures. When heated to decomposition this compound emits toxic fumes of hydrogen chloride gas, CO and CO2.