Overview This report provides an introduction to polycyclic aromatic hydrocarbons (PAHs) for persons working in the petroleum industry. It describes what PAHs are and how they are formed, PAH environmental transport, fate, and health effects, regulatory requirements related to PAHs, and analytical methods for measuring PAH concentrations in the environment. This information is of particular relevance to the petroleum industry due to the natural presence of PAHs in crude oil, the formation of PAHs during some refining processes, and the production of PAHs throughout the combustion of petroleum products. The intended audience for this report includes environmental professionals who must address PAH regulatory issues, and field personnel who are responsible for the sampling and analyses of PAHs.