A major regional pipeline began leaking Sunday, July 25, into the Tallmadge Creek south of Marshall, Mich. The creek carried the crude oil into the Kalamazoo River. The leak is potentially one of the largest oil spills in the Midwest. In this video, Dr. Steve Hamilton, professor at the W.K. Kellogg Biological Station, explains what happened, the response, the short-term and long-term effects, what people living in the area need to be aware of and how they can help.