The flow station, one of several, separates fluids that are produced into marketable crude oil for the trans-Alaska pipeline, and water and gas, said John Ebel of the Alaska Department of Environmental Conservation.

The water and gas are generally re-injected into the field, said Ebel.

About 200 gallons of fluids were spilled last Thursday.

The flow station, one of several at Prudhoe Bay, was still shut down Monday to study the cause of the leak, install some new parts, and re-work the gravel in berms surrounding containment pits, said Ebel.

The effects on the flow of oil into the pipeline will be "minor and short term," said Steve Rinehart, spokesman for BP. He said various production facilities go on and offline during summer months due to maintenance and testing, and the oil flow fluctuates.

In another incident, one barrel of oil spilled next to a BP-operated gravel drilling and production pad on Saturday.

And on July 16, a North Slope pipeline operated by BP ruptured during a pressure test. That spill was estimated last week at 2,100 to 4,200 gallons.