Two oil pipelines on Alaska's North Slope are going to be shut down because of internal corrosion. At least something's happening - this was the cause of a huge spill earlier this year in the aging Prudhoe Bay oil field.

"The line was not producing a continuous flow. An X-ray of the pipe showed internal corrosion in an arrow shape, indicating the damage was being aided by the velocity of fluid moving through the pipe, Johnson said."

"We started to conclude last year that corrosion inhibitor alone might not stop this problem," said Maureen Johnson, a BP senior vice president.

"Corrosion was blamed for a leak in a pipeline in early March that caused the largest spill in Prudhoe's nearly 30-year history. About 200,000 gallons of oil is believed to have spilled from a transit line, although officials with the Department of Environmental Conservation say the amount could be anywhere from 130,000 gallons to 265,000 gallons." Corrosion Leads to Shut Down of Pipelines »