The Kalamazoo River oil spill occurred in July 2010 when a pipeline operated by Enbridge (Line 6B) burst and flowed into Talmadge Creek, a tributary of the Kalamazoo River. A 6-foot (1.8 m) break in the pipeline resulted in one of the largest inland oil spills in U.S. history (the largest was the 1991 spill near Grand Rapids, Minnesota). The pipeline carries diluted bitumen (dilbit), a heavy crude oil from Canada's Athabasca oil sands to the United States. Cleanup took five years. Following the spill, the volatile hydrocarbon diluents evaporated, leaving the heavier bitumen to sink in the water column. Thirty-five miles (56 km) of the Kalamazoo River were closed for clean-up until June 2012, when portions of the river were re-opened. On March 14, 2013, the Environmental Protection Agency (