( Reuters ) - An explosion crippled the biggest pipeline supplying Canadian crude to U.S. Midwest refineries, shutting off more than 1 million barrels per day of imports to the world's biggest consumer.
The cause of the explosion on the Enbridge Pipeline (ENB.TO) (EEP.N) system Wednesday that killed two employees was not immediately known.
U.S. crude oil prices Thursday vaulted more than $4 to just over $95 per barrel in early trading.
Crude later eased to near $93 after news the main fire had been put out and that 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 bpd of Canadian crude, about 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 bpd, would restart.
Line 3, with capacity of nearly 450,000 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 Thursday. "The fire in line 3 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.
Officials at several Midwest refineries were not immediately available to comment on whether the outage would affect fuel production from their plants.
Most Midwestern refineries have some limited alternative supply options on underused pipelines such as Capline, which supplies the Wood River and Chicago areas, and the Wood River pipeline, which supplies plants in Minnesota.