The U.S. pipeline safety agency has launched an investigation into an oil spill in Wisconsin on Enbridge Inc's network that forced the shutdown of a section of a main artery carrying light sweet Canadian crude to Chicago-area refineries.
Enbridge's 318,000 barrel per day Line 14 pipeline, part of the Lakehead system, was shut on Friday after an estimated 1,200 barrels of oil were leaked.
The spill happened almost two years to the day after another major spill in a different section of the system, in Michigan, and marks the latest in a string of disruptions from the Canadian company in recent years.
Canada is the largest oil exporter to the United States and Enbridge's pipelines carry the lion's share of that crude.
The following lists Enbridge's pipeline spills and incidents over the last decade:
* June 2012 - Enbridge shuts 345,000 bpd Athabasca pipeline after 1,400 barrels of oil were spilled near Elk Point in northeast Alberta. The line was quickly restarted after the company was able to bypass the Elk Point pump station.
* March 2012 - Enbridge shuts the 318,000 bpd line 14/64 between Superior, Wisconsin, and Griffith, Indiana, after an SUV crashed into a pumping station near New Lenox, Illinois.
* September 2011 - Enbridge shuts Line 26, a 25,000 bpd oil pipeline running from Berthold, North Dakota, to Steelman, Saskatchewan, for one day after about 20 barrels of oil were spilled from a pumping station at Berthold.
* May 2011 - Enbridge estimates between 700 and 1,500 barrels of oil spilled from the 39,400 bpd Norman Wells pipeline south of Wrigley, Northwest Territories.
* November 2010 - Throughput on the 670,000 bpd Line 6A, which feeds Midwest refineries and the key Cushing, Oklahoma, crude oil hub, reduced after a problem with a power disruption from a local utility in Lockport, Illinois.
* September 2010 - Enbridge closed its 70,000 bpd Line 10, which runs from Westover, Ontario, to New York state, while the company investigated a small leak. It was quickly restarted when it was determined to be leak-free.
* September 2010 - Enbridge closed Line 6A for eight days after it leaked 6,100 barrels of crude near Romeoville, Illinois.
* July 2010 - Enbridge shut its 290,000-bpd Line 6B, which runs from Griffiths, Indiana, to Sarnia, Ontario, on July 26 after a rupture near Marshall, Michigan, spilled about 20,000 barrels into the Kalamazoo River system.
* January 2010: An Enbridge pipeline leaked around 3,000 barrels of crude near Neche, North Dakota. Authorities ordered Enbridge to reduce pressures on the line, and in a letter to Enbridge, raised concerns over the strength of some of its pipeline seams.
* November 2007: Two workers were killed after an Enbridge-operated pipeline caught fire in northern Minnesota. The same line had recently been repaired. Following the incident, which resulted in a pipeline closure, up to 20 percent of U.S. crude imports were temporarily halted. Enbridge was fined for having allowed pressure on the pipeline to exceed recommended limits.
* January 2007: A spill on an Enbridge line transporting Canadian crude to Chicago leaked around 1,190 barrels in rural Wisconsin. About a month later, and further north, the pipeline spilled 2,976 barrels after a construction crew broke the line.
* 2005: Enbridge spilled more than 9,825 barrels of oil in several incidents over the year, according to National Wildlife Federation data compiling spill volumes. Most oil was quickly contained by Enbridge.
* June 2003: Enbridge spilled around 452 barrels in Wisconsin's Nemadji River, and additional crude spilled from an Enbridge terminal was contained.
* July 2002: 6,000 barrels spilled from an Enbridge pipeline into marshlands near Cohasset, Minnesota.
Sources: Department of Transportation, Enbridge, spill data compiled by the National Wildlife Federation, SEC filings.