This project addresses the potential for contamination of soil and surface water associated with natural oil seeps and improperly decommissioned oil wells in Southern California. Study sites have been identified in the Towsley Canyon area in Santa Clarita, CA, in Simi Valley, CA, near Ojai, CA, and near Santa Paula, CA. We have conducted four sampling events and optimized analytical procedures for crude oil analysis. The initial results indicate that oil primarily impacts only the immediate vicinity of the seeps during low-flow conditions, but that large amounts of oil are transported far downstream during storm events, including to a popular county park. My graduate student, Alfredo Estrada, has presented these preliminary results at two conferences, with a third scheduled for Spring 2021. We will continue sampling through the Winter and Spring, incorporating additional sites and a range of flow conditions. Funded by CSU Council on Ocean Affairs, Science & Technology (COAST) Grant Development Program.