Chrysene

Chrysene is a polycyclic aromatic hydrocarbon (PAH) with the molecular formula C18H12 that consists of four fused benzene rings. It is a natural constituent of coal tar, from which it was first isolated and characterized. It is also found in creosote, a chemical used to preserve wood.
High purity chrysene is colorless, the yellow hue being due to the traces of its yellow-orange isomer tetracene, which cannot be separated easily. Chrysene is formed in small amounts during the burning or distillation of coal, crude oil, and plant material.
As with other PAHs, chrysene is suspected to be a human carcinogen. It is known to cause cancer in laboratory animals.