The cause of the explosion on Wednesday that killed two employees was not immediately known.
U.S. crude oil prices on Thursday vaulted more than $4 a barrel to just over $95 in early trade.
It later eased to just over $93 a barrel after news the main fire was out and two of four connected lines had restarted, but analysts were still worried about the impact on supplies ahead of peak winter demand.
"The timing is pretty bad. We are coming to the strongest demand period for crude with the approach of the northern winter," said Mark Pervan of ANZ.
During the third quarter, the pipeline had carried around 1.5 million barrels per day of Canadian crude, or around 15 percent, of U.S. imports.
There was no word on when line 4, the biggest of the connected pipes, which ships nearly 700,000 barrels per day (bpd), would restart.
Line 3, with capacity of nearly 450,000 barrels per day (bpd) had been shut earlier to inspect a leak and was also still out of action.
"Two of the four pipelines have restarted," Larry Springer, a spokesman for Canadian operator Enbridge said on Thursday. "The fire in line three in the last hour has been extinguished, but there could be other fires around it."
He did not specify how much throughput had been restored.
Güncelleme Tarihi: 30 Kasım 2007, 11:16