FACTBOX: Enbridge Canada-U.S. oil pipeline world's biggest

(Reuters) - The Enbridge pipeline system that ships nearly 2 million barrels per day (bpd) of Canadian crude and fuel from Alberta to the U.S. Midwest and some Canadian refineries is the world's longest and most sophisticated, the company says.

An explosion and fire on the pipeline three miles southeast of the Clearbrook, Minnesota, oil terminal occurred on Wednesday at approximately 3:45 p.m. CST, killing two employees and halting shipments that make up nearly a tenth of U.S. imports.

All Enbridge pipelines in the vicinity -- Lines 1, 2, 3 and 4 -- were immediately shut down and isolated and Enbridge emergency crews were dispatched to the site, it said. Those lines pumped some 1.5 million barrels per day (bpd) in the third quarter.

Find additional details about the lines affected, the types of crude oil involved and refineries below:

THE FOUR AFFECTED LINES:

The fire broke out on line 3, which had been shut down for maintenance on Wednesday in order to investigate a small leak, Enbridge spokesman Larry Springer told Reuters.

He said all four lines of the pipeline will be shut down until the fire dies down enough to allow for inspections of lines 1 and 2, which are located several hundred feet away from the source of the fire and explosion. Springer warned that larger Lines 3 and 4 were likely to remain shut for some time.

Details of the four lines, according to the Enbridge Web site:

LINE 1: capacity 237,000 bpd.

Carries natural gas liquids and refined oil products. Needs to be investigated by company before restarted; investigations to begin once the fire burns down sufficiently.

LINE 2: capacity 409,000 bpd.

Carries condensates, synthetics, light and medium crudes. Needs to be investigated by company before restarted; investigations to begin once the fire burns down sufficiently.

"There is nothing from any other sources that would make us think there is any damage (to Lines 1 and 2), but as prudent operators we have to inspect them before we start them back up."

LINE 3: capacity 447,000 bpd.

Carries light, medium and heavy crudes. Will require repairs and inspection by the company and by regulatory agencies before being restarted. "(Line 3) will be the one that take the most work, it will need repairs plus the investigations."

LINE 4: capacity 669,000 bpd.