Factbox: History of Enbridge's pipeline spills in the U.S

CALGARY (Reuters) - Enbridge Inc shut down the largest of its three major oil pipelines due to a leak in Illinois on Thursday, reducing supply on the main transit route for Canadian crude into the United States.

Canada is the largest oil exporter to the United States and Enbridge’s pipelines carry the lion’s share of that crude.

The incident occurred just six weeks after an Enbridge pipeline ruptured in southern Michigan and caused one of the largest pipeline leaks in recent U.S. history.

The size of the July spill -- at least three times bigger than the notorious 2006 BP pipeline spill in Alaska that caused costly disruptions and repairs -- and the fact Enbridge had been warned about potential corrosion on the line, is raising eyebrows among regulators and in Congress.

The following lists Enbridge’s pipeline spills in the United States over the last decade:

* September 9 - Enbridge closed its 670,000 barrel-per-day Line 6A, which feeds Midwest refineries and the key Cushing, Oklahoma crude oil hub after a leak was discovered near Romeoville, Illinois. Though the size of the spill is not yet known, local fire officials said the line was shut early in the afternoon and that the oil has been contained.

* July 26 - Enbridge shut its 190,000-bpd Line 6B, which runs from Griffiths, Indiana, to Sarnia, Ontario, on July 26 after a rupture near Marshall, Michigan, spilled 19,500 barrels (819,000 gallons) into the Kalamazoo River system.

Though repairs were completed in August, U.S. regulators have not yet allowed the company to restart shipments on the line, forcing Enbridge to ration use of its remaining lines. It was one of the largest pipeline leaks in recent U.S. history.

* January 2010: An Enbridge pipeline leaks around 3,000 barrels (126,000 gallons) of crude near Neche, North Dakota. Authorities order Enbridge to reduce pressures on the line, and in a letter to Enbridge, raise concerns over the strength of some of its pipeline seams.

* November 2007: Two workers are killed after an Enbridge-operated pipeline catches 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 that transports Canadian crude to Chicago, Illinois, leaks around 50,000 gallons (1,190 barrels) of crude in rural Wisconsin. About a month later, and further north, the pipeline again spills around 125,000 gallons (2,976 barrels) after a construction crew breaks the line.

* 2005: Enbridge spills more than 412,650 gallons (9,825 barrels) of oil in several incidents over the year, according to National Wildlife Federation data compiling spill volumes. Most oil is quickly contained by Enbridge.

* June 2003: Enbridge spills around 19,000 gallons (452 barrels) in Wisconsin’s Nemadji River, and additional crude spilled from an Enbridge terminal is contained.

* July 2002: 252,000 gallons (6,000 barrels) spill from an Enbridge pipeline into marshlands near Cohasset, Minnesota.

Sources: Department of Transportation documents, Enbridge spill reports, spill data compiled by the National Wildlife Federation, SEC filings.