On Saturday an 8-inch pipeline burst at one of BP's largest facilities on Alaska's North Slope, spilling thousands of gallons of methanol and oily water. The pipeline was a part of a facility that has had a string of problems in recent years. At least one pipeline there was ranked by the company as being severely corroded last year.

But when BP officials got back to ProPublica Monday night, they clarified that the pipeline that burst was not the same one previously flagged for urgent repair or replacement. A story published earlier today by ProPublica reported that it had been the same pipeline.

It was, in fact, a different, similarly named pipeline at the same facility.

The line that burst Saturday, at a processing facility called the Lisburne Production Center, was being pressure-tested after a monthlong shutdown of the facility for routine maintenance, according to a spokesman for BP, Scott Dean. Dean said in an email that the leak was detected immediately and that the pressure test that caused it was part of a planned integrity inspection of the pipeline. Such inspections are "one of the ways a prudent operator ensures safe and reliable pipeline operations."

Last November, ProPublica reported that BP had detected severe corrosion on parts of 148 of the company's pipelines on Alaska's North Slope, including a line at the Lisburne Production Center, and had "F-Ranked" the pipelines for immediate repair or replacement.

The troubled section of that pipeline, Dean said, has since been replaced. The line that ruptured Saturday has never received an F-rank by the company.