 B"a"P is discharged in wastewater by industries such as smelters, particularly iron and steel mills and aluminum smelters.In the 18th century, young British chimney sweeps who climbed into chimneys suffered from chimney sweeps' carcinoma, a scrotal cancer peculiar to their profession, and this was connected to the effects of soot in 1775, in the first work of occupational cancer epidemiology and also the first connection of any chemical mixture to cancer formation.Frequent skin cancers were noted among fuel industry workers in the 19th century.