Hexachlorobenzene is a white crystalline solid. This compound does not occur naturally. Hexachlorobenzene was widely used as a pesticide until 1965. It was also used to make fireworks, ammunition, and synthetic rubber. It is formed as a by-product during the manufacture of chemicals used as solvents, other chlorine-containing compounds, and pesticides. Small amounts of hexachlorobenzene can also be produced during combustion processes such as burning of city wastes. It may also be produced as a by-product in waste streams of chlor-alkali and wood preserving plants. There are no current commercial uses of the substance.
Structural diagram: National Institutes of Health
Fate & Transport
Hexachlorobenzene tends to remain as a solid in the environment for a long time. If it is released to the soil, it has a half-life of from 3 to 6 years. This means that half the total amount will disappear after 3-6 years, half the remaining amount will disappear in another 3-6 years, and this process will continue each 3-6 years thereafter. If it is released to lakes and groundwater, the half-life of the substance is 30-300 days. Most of it will be in the form of particles clinging to the bottom and sides of lakes or streams, since it does not dissolve in water very well. The evaporation of this substance into the air is not significant under ordinary conditions. Once in the air, it is not clear how long its particles remain in the air.
Information excerpted from:
Toxicological Profile for Hexachlorobenzene August 1994 Draft Update