Occupational studies of workers exposed to mixtures of PAHs (e.g. coal tar, coke oven emissions, soot, shale and crude oil) provide evidence that certain PAHs are carcinogenic in humans. Lung cancer is associated with inhalation exposure, and skin cancer with dermal exposure to PAH-containing mixtures. Animal data suggest that humans exposed to PAHs may be at risk for developing haematological diseases. Glossary.