HCB  is an important environmental  toxicant that affects multiple organ systems, including the reproductive and immune systems.  Although HCB as an anti fungal pesticide has been banned in many countries and will be eliminated worldwide as a result of the Stockholm Convention on persistent organic pollutants, it still enters the environment as a byproduct of chemical manufacturing, wood preservation, and municipal garbage burning. 

Accumulation in wheat, grasses, and some vegetables from the soil has caused the chemical to become concentrated in plants, herbivores, and carnivores.  Humans are primarily exposed through dairy products, meat, and fish.  Low levels of HCB have been noted in almost all people tested, according to the Agency for Toxic Substances and Disease Registry.  While single small doses are relatively nontoxic, continued exposure to even small amounts can affect human health.

Reference:  Physicians for Social Responsibility, June/July 2004, p. 6  Exendam, J., F. Staedtler, et al - Environmental Health Perspectives, Vol. 2004 - 112(7): 782-791