Operations at the nation's largest oil field were halted when the power supply to processing centers was knocked offline.

An operator of a frontloader clearing snowdrifts early Friday struck an airline at the Central Power station, interrupting the supply of fuel to generators at Prudhoe Bay.

Six plants shut down, and the gas supply was interrupted to a seventh plant, also causing it to shut down.

Steve Rinehart, a spokesman for field operator BP PLC, says the power supply has been re-energized. Four of the plants are expected back online later Friday. The rest are expected back in operation Saturday.

There were no injuries, and power supplies to workers' camps and other facilities were not interrupted.