ABSTRACT
The history of the detection, synthesis, and biological study of polycyclic aromatic hydrocarbons (PAH) is closely related to the establishment of the carcinogenicity of coal tar. Studies of occupational hazards related to coal tar pitch volatiles in general and PAH in particular have a long history. Biological and toxicological studies show that many PAH compounds exhibit carcinogenic effects in experimental animals, demonstrating that PAH is the largest class of chemical carcinogens known today. Although no work environment has PAH as its only pollutant, epidemiological studies of workers exposed mainly to PAH indicate an increased risk of lung cancer related to PAH exposure in work atmospheres. For a single occupation there seems to be a correlation between duration and degree of exposure (tar-years) and cancer incidence. However, comparing levels of exposure in different occupations and industries, there is no apparent correlation with cancer incidences.
