On March 14, 2013, the Environmental Protection Agency (EPA) ordered Enbridge to return to dredge portions of the river to remove submerged oil and oil-contaminated sediment.

On Sunday, July 25, 2010, at about 5:58 p.m. EDT, a 40-foot (12 m) pipe segment ruptured in the 30-in (760-mm) Enbridge Energy Line 6B, approximately 0.6 miles (1.0 km) downstream of the Marshall, Michigan pump station.

[4] The rupture caused a spill of diluted bitumen originating from Canada (Alberta and Saskatchewan) into Talmadge Creek in Calhoun County, Michigan, which flows into the Kalamazoo River.

[6] Alarms sounded in Enbridge's Edmonton headquarters at the time of the rupture, but control-room staff were unable to interpret them with certainty and remained unaware of the pipeline breach.

Dilbit, like all crude oil, floats in water but, over time, will sink, complicating cleanup efforts, particularly if dredging is considered too ecologically damaging.

[13] In July 2016, Enbridge agreed to pay $177 million in penalties and improved safety measures in a settlement with the U.S. Justice Department and the Environmental Protection Agency.

[14] In July 2012, the National Transportation Safety Board, the U.S. federal agency with regulatory authority over the failed pipeline, issued a report representing the official conclusion of the investigation into the incident.

Local firefighters were notified, and tried to locate the southern Michigan wetland site of the breach, but were initially unable to do so, further delaying the shutdown of the line.

[16] NTSB Chair Deborah Hersman likened "Enbridge's poor handling" of the spill to the Keystone Cops, asking: "Why didn't they recognize what was happening, and what took so long?"

Based on the successful completion of the work by Enbridge, the EPA transitioned the oversight of the remaining obligations to the Michigan Department of Environmental Quality in 2014.