Petroleum is a complex mixture of many compounds. Regulatory and technical guidance documents commonly focus on the hydrocarbon components of that mixture, or perceived risks that they present. However, focusing on a specific area of concern often causes practitioners to overlook other aspects of a release. For example, concerns related to exposure to total petroleum hydrocarbons (TPH) risks may be overlooked while pursuing concerns related to light non-aqueous phase liquid (LNAPL) recovery or petroleum vapor intrusion (PVI).This class hosted by the Interstate Training and Regulatory Council (ITRC) is designed to provide a basic overview of hydrocarbon behavior in the subsurface and how to scientifically assess concerns arising from the release of petroleum products into the environment. It will highlight key issues that help identify and manage TPH, LNAPL, and PVI risks together.