Presentation summarizes the physical chemical properties of compounds found in crude oil and how these properties drive the behavior of the compounds during a spill event. PAHs are presented as a complex mixture of multiple compounds that could be measured but most studies are limited to the main 16 priority PAHs. The family of PAH compounds can be used to distinguish source as used in environmental forensics studies. Lastly, a look to the future as a result of all the research into the gulf oil spill reveals that the science of monitoring of oil spills is about to change. It will not involve many more compounds and likely trigger more regulated substances.