3 Pollution and the Emergency Management of Coastlines One of the biggest threats to marine environments is pollution, which can come from a variety of sources such as industrial plants, sewage, powers stations (which cause thermal pollution) and the oil industry. It is the last of these that has become one of the most vexing forms of pollution, because of the difficulties in managing oil spills and the long-term effects that may result. Huge amounts of oil are trans- ported vast distances around the world in some of the biggest vessels built.