Coal. Iron ore. Grain. Limestone. Cement. Salt. Wood pulp. Wind turbine components. Steel coil. All of these commodities and more, at one point or another, have made their way out of the Duluth-Superior port and onto the open waters of Lake Superior aboard ships. In a few years, another commodity could possibly be added to that list. Calumet Specialty Product Partners, a petroleum refiner located in Superior, Wisconsin, has been moving forward with the first steps of a process to construct a crude oil loading dock in the port. In this edition of the Lake Superior Project, we speak with Lyman Welch of the Alliance for the Great Lakes, about the potential for shipping tar sands oil on the Great Lakes.