An estimated three million litres of oil spilled into a creek that flows into the Kalamazoo River after a 30-inch pipeline ruptured near Marshall, Mich.
Heavy rains caused the river to overtop existing dams and carried oil roughly 50 kilometres downstream polluting the waters and coating various fish and wildlife before the spill was contained.
The EPA says more cleanup is needed in three locations: upstream of Ceresco Dam, upstream of the Battle Creek Dam in the Mill Ponds area, and in the delta upstream of Morrow Lake.
Prior orders from the EPA directing Enbridge to complete other cleanup and restoration work in the Kalamazoo River system are still in effect.
The agency said oil spill response workers have collected more than 1.1 million gallons of oil and almost 200,000 cubic yards of oil-contaminated sediment and debris from the Kalamazoo River system.