FACTBOX-Accidents on Enbridge oil pipeline system in 2007

Nov 29 (Reuters) - An explosion and fire on the giant Enbridge crude oil pipeline system near Clearbrook, Minnesota, forced the partial shutdown of the system which transports two-thirds of the Canadian crude oil imported into the United States.

The entire system is comprised of more than a dozen pipelines in various parts of North America with a combined capacity of 2.2 million barrels per day. The mainline between Alberta and Superior, Wisconsin, transports approximately 1.5 million bpd, most of which goes to refineries in the U.S. Midwest. The remainder is shipped to refineries in Central Canada.

Capacity on the pipeline is growing tight due to rising oil production in Alberta and Enbridge has been working to expand the pipeline. The system suffered several incidents this year prior to the blast on Wednesday. A list of these incidents follows: JANUARY 3

- 300,000 bpd Line 14, which connects Superior, Wisconsin, to Chicago, ruptures in rural Wisconsin. The line is shut for approximately 24 hours. FEBRUARY 2

- Line 14 suffers another leak in Wisconsin. Nearby 630,000 bpd Line 6A, which connects Superior, Wisconsin to Chicago, is also shut as a precaution. APRIL 16

- 450,000 bpd Line 3, which connects Hardisty, Alberta, with Superior, Wisconsin, has a leak near Gleavon, Saskatchewan. NOVEMBER 14

- Line 3 shut for 18 hours after small spill discovered near Clearbrook, Minnesota. Nearby 670,000 bpd Line 4, which connects Edmonton, Alberta, with Superior, Wisconsin, is also shut as a precaution. NOVEMBER 29

- Explosion and fire kills two workers who were inspecting the pipeline. Lines 1 through 4 are shut. Two lines are restarted within hours of the blast. (Reporting by Robert Campbell, editing by Matthew Lewis)