Enbridge Line 6 Oil Pipeline

From Global Energy Monitor
This article is part of the Global Fossil Infrastructure Tracker, a project of Global Energy Monitor.

Enbridge Line 6 Oil Pipeline is a major oil pipeline in the Enbridge Pipeline System, which conveys petroleum from western Canada to eastern Canada via the Great Lakes states. It consists of two separate pipelines, Line 6A and Line 6B. Line 6B resulted in the largest on-land oil spill in American history when in ruptured in July 2010, spilling more than one million barrels into a tributary of the Kalamazoo River in Michigan.


Line 6A originates in Superior, Wisconsin and terminates in Griffith, Indiana. Line 6B originates in Griffth, Indiana and terminates in Sarnia, Ontario.

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Project details

  • Operator:Enbridge[1]
  • Owner: Enbridge[1]
  • Parent company: Enbridge[1]
  • Capacity: 667,000 barrels per day[1]
  • Length: 465 miles[1]
  • Diameter: 34 inches[2]
  • Status: Operating[1]
  • Start year: 1969
  • Cost:
  • Financing:
  • Associated infrastructure:

Kalamazoo River oil spill

The Kalamazoo River oil spill, also described as The Dilbit Disaster,[3] occurred in July 2010 when Line 6B burst and flowed into Talmadge Creek, a tributary of the Kalamazoo River. A 6 foot 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. Following the spill, the volatile hydrocarbon diluents evaporated, leaving the heavier bitumen to sink in the water column. Thirty-five miles 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 (EPA) ordered Enbridge to return to dredge portions of the river to remove submerged oil and oil-contaminated sediment.

The spill

On Sunday, July 25, 2010, at about 5:58 p.m. EDT, a 40-foot pipe segment in Line 6B, located approximately 0.6 miles downstream of the Marshall, Michigan pump station, ruptured.[4] The rupture in the Enbridge Pipeline System|Enbridge Energy pipeline caused a spill of diluted bitumen or heavy crude oil originating from Canada (Alberta and Saskatchewan) into Talmadge Creek in Calhoun County, Michigan, which flows into the Kalamazoo River. The EPA later estimated the spill to be in excess of 1 million US gallons.[5] On 29 July 2010, the Calhoun County Health Department asked 30 to 50 households to evacuate, and twice as many were advised not to drink their water.[6]

Photo Credit: NRDC

Though alarms sounded in Enbridge's Edmonton headquarters at the time of the rupture, it was eighteen hours before a Michigan utilities employee reported oil spilling and the pipeline company learned of the spill. Meanwhile, pipeline operators had thought the alarms were possibly caused by a bubble in the pipeline and, while for some time it was shut down, they also increased pressure for periods of hours to try to clear the possible blockage, spilling more oil.[7]

The oil was contained to a 25-mile stretch of the Kalamazoo River as several hundred workers took part in the cleanup.[8] Regional EPA Director Susan Hedman estimated that it would take weeks to remove the bulk of the oil from the river, several months to clear oil from the flood plains, and several more months to clean the oil out of the marsh where the spill originated. However, a year later, a 35-mile stretch of the river remained closed.[9] Originally estimated at US$5 million,[10] by September 2011, cleanup costs passed $585 million and were expected to rise by 20 percent.[9] The cleanup expense by summer 2012 had totalled $765 million.[7] By November 2014, the total had risen to $1.21 billion, with an estimated $219 million in costs yet to be paid.[11]


In June, 2012, authorities reopened most of the 35 miles of the river that had been closed to recreation after the spill. Part of the river at the Morrow Lake delta remained closed and other sections of the river remain restricted because of the ongoing cleanup of the tar sands oil product called diluted bitumen (dilbit) oil the pipeline had been transporting.[12]

The United States Department of Transportation fined Enbridge $3.7 million, listing 22 probable violations that happened relating to the spill.[7]

One of the reasons for the vast escalation in time and expense of cleanup was that the EPA had never handled a dilbit spill. In addition, it is reported that Enbridge never informed the EPA of the product distinction. Dilbit, like all crude oil, floats in water but, over time, will sink, complicating cleanup efforts, particularly if dredging is considered too ecologically damaging.[7] Other environmental factors will affect the rate at which this process takes place. This disaster was the largest on-land spill in American history to date.[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]

National Transportation Safety Board investigation

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. The investigators found that the operating firm, which had received an automated signal from the pipeline that a breach had occurred, misunderstood or did not believe the signal and attempted to continue to pump dilbit oil through the pipeline for 17 hours after the breach. 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.[15]

The NTSB investigation synopsis pointed to corrosion fatigue as the underlying cause of the catastrophic breach. The incident was exacerbated by the pipeline's disbonded polyethylene tape coating. In July 2012, the cost of the cleanup operations was estimated at $767 million.[15] The NTSB stated the Enbridge dilbit oil spill is, as of 2012, the costliest onshore cleanup in U.S. history.[16] NTSB Chair Deborah Hersman likened "Enbridge's poor handling" of the spill to the Keystone Kops, asking: "Why didn't they recognize what was happening, and what took so long?" NPR reported that "NTSB investigators determined that the 6-foot gash in the pipe was caused by a flaw in the outside lining which allowed the pipe to crack and corrode. Now, in 2005, Enbridge actually had learned that this section of pipe was cracked and corroding. ... That same 2005 internal report pointed to 15,000 defects in the 40-year-old pipeline. And Enbridge decided not to dig up this Talmadge Creek area to inspect it."[17]

In 2013, in opining on the Keystone XL pipeline proposal, the EPA recommended to the State Department that pipelines that carry tar sands oil should no longer be treated just like pipelines that carry any other oil. Stephen Hamilton, an ecology professor at Michigan State University and the independent science adviser at Talmadge Creek, detailed the challenges and expense of the still-ongoing Michigan cleanup.[18][19]

Additional dredging under 2013 order

The EPA issued an Order for Removal in 2013 which required Enbridge to remove oil-contaminated sediment from specific locations along the Kalamazoo River, including the three areas where submerged oil was most pronounced:

  • Upstream of the Ceresco Dam
  • Mill Ponds area
  • Morrow Lake, Morrow Lake Delta and adjacent areas
  • Sediment traps at two designated locations[20]

By the fall of 2014, Enbridge had completed the remaining obligations under the 2013 Order for Removal, including the dredging of oil-contaminated sediment. 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.[21]

Line 6B Reconstruction

Following the Kalamazoo River oil spill, Enbridge fully replaced Line 6B at a cost of $2.63 billion, with the new pipeline placed in service in October 2014.[22][23] The replacement doubled the operating capacity of Line 6B to 500,000 barrels per day.[24] Note Line 6B is now known as Enbridge Line 78 Oil Pipeline.

Map Credit: Enbridge

Articles and resources


  1. 1.0 1.1 1.2 1.3 1.4 1.5 Enbridge’s Energy Infrastructure Assets Enbrdige, July 22, 2020
  2. Enbridge’s Energy Infrastructure Assets Enbrdige, July 22, 2020
  3. Elizabeth McGowan, Lisa Song, and David Hasemyer (2016). The Dilbit Disaster: Inside the Biggest Oil Spill You've Never Heard of. Createspace Independent Publishing Platform. ISBN 9781539009597. Retrieved 25 March 2017.{{cite book}}: CS1 maint: multiple names: authors list (link)
  4. "Crude Oil Pipeline Rupture and Spill". 26 July 2010. Archived from the original on 30 June 2012. Retrieved 19 Oct 2012. {{cite news}}: Unknown parameter |dead-url= ignored (help)
  5. EPA Raises Oil Spill Estimate In Michigan River Template:Webarchive
  6. Lambert, Sarah (30 July 2010). "Air quality spurs evacuations in oil spill area". The Battle Creek Enquirer. Retrieved 30 July 2010.
  7. 7.0 7.1 7.2 7.3 "Kalamazoo River Spill Yields Record Fine", Living on Earth, July 6, 2012. Lisa Song, a reporter for InsideClimate News, interviewed by Bruce Gellerman. Retrieved 2013-01-01.
  8. "EPA notes improvements at Michigan oil spill site". Google News. Associated Press. 1 August 2010. Retrieved 2 August 2010.
  9. 9.0 9.1 Johnson, Kirk and Dan Frosch. "Rancor Grows Over Planned Oil Pipeline From Canada" New York Times. September 28, 2011. Retrieved September 28, 2011.
  10. Wood, Michael (1 August 2010). "Enbridge spill clean-up will take months". The Toronto Sun. Retrieved 2 August 2010.
  11. Ellison, Garret (6 November 2014). "New price tag for Kalamazoo River oil spill cleanup: Enbridge says $1.21 billion". Grand Rapids Press. Retrieved 25 January 2017.
  12. Lawrence, E., (June 21, 2012). Most of Kalamazoo River now open following July 2010 Enbridge oil spill. Detroit Free Press.
  13. "The Arkansas Pipeline Leak Is Another Tar Sands Red Flag", The Atlantic, April 1, 2013.
  14. Valerie Volcovici (July 20, 2016). "U.S., Enbridge reach $177 million pipeline spill settlement". Reuters. Retrieved September 21, 2016.
  15. 15.0 15.1 "Enbridge, Inc. Hazardous Liquid Pipeline Rupture". National Transportation Safety Board. Retrieved 2012-07-11.
  16. http://www.foxbusiness.com/news/2012/07/20/enbridge-to-spend-up-to-c500-million-more-on-northern-gateway-safety/. Retrieved 2012-07-22. {{cite web}}: Missing or empty |title= (help)[dead link]Template:Cbignore
  17. Shogren, Elizabeth, "Firm blamed in the costliest onshore oil spill ever" (transcript), NPR, July 10, 2012. Retrieved 2013-04-24.
  18. EPA (27 July 2010). "EPA Response to Enbridge Spill in Michigan". United States Environmental Protection Agency. Retrieved 29 July 2010.
  19. Shogren, Elizabeth, "EPA: Tar Sands Pipelines Should Be Held To Different Standards", NPR, April 24, 2013. Link to EPA letter to State Department. Retrieved 2013-04-24.
  20. United States Environmental Protection Agency [1] In the Matter of Enbridge Energy, Limited Partnership - Order for Removal Under Section 311(c) of the Clean Water Act. Retrieved: 2015-11-24.
  21. United States Environmental Protection Agency [2] EPA's Response to the Enbridge Oil Spill. Retrieved: 2015-11-24.
  22. Line 6B Replacement Project, Enbridge, accessed 7 Sep. 2017
  23. Application to Michigan Public Service Commission, Case No. U-17020 Enbridge, 16 Apr. 2012
  24. Path of least resistance, Journal Sentinel, 13 Jan. 2017

Related GEM.wiki articles

External resources

Wikipedia also has an article on Kalamazoo River oil spill. This article may use content from the Wikipedia article under the terms of the GFDL.

External articles