FERNDALE — BP says the Feb. 17 fire that shut down its Cherry Point oil refinery near Ferndale was caused by a pipe failure in the crude processing unit.

The failure was a result of a corrosion problem, said Bill Kidd, spokesman at BP Cherry Point. The pipe is relatively small - about six inches in diameter - and is generally used only in start-up and shut-down situations at the refinery. However, heated material unexpectedly flowed into the pipe. The combination of liquid and gases churning created the pipe weakness.

At this point in the investigation, it's unclear how long the corrosion problem was taking place in the pipe, said BP spokesman Mike Abendhoff.

"It could have been a problem from Day 1 or was something more recent. It's hard to say at this point," Abendhoff said.

Kidd said a variety of additional safety measures have been implemented: Along with replacing the pipe, additional monitoring points were added and each pipe in the facility was inspected.

"We've identified the problem and we're confident that this (corrosion) issue isn't happening anywhere else," Kidd said.

BP had a monitor in the area of the pipe failure, but Kidd said they focused on the elbow portion of the pipes because that's the most likely area a problem would occur.

"This (failure) happened on the ridge at the top of the pipe," Kidd said.

With the current issue resolved and BP Cherry Point once again running at capacity, officials are considering a potential redesign of the pipes as a long-term project.

While repairing the pipe, BP added a maintenance turnaround; at its peak those projects required more than 3,200 additional workers at the site. The refinery returned to operation at the end of May. Its outage is considered a factor in high West Coast gasoline prices.

The fire is being investigated by government agencies, including the Department of Labor & Industries. Spokeswoman Elaine Fischer said L&I's investigation is expected to be completed later this summer. If serious violations are found during the investigation, fines and citations will be issued.

The pipe failure on Feb. 17 resulted in flames shooting into the air and a plume of black smoke that could be seen for miles. The fire was extinguished within an hour after it started and no major injuries were reported.

Kidd said the reaction by the company's fire teams following the pipe failure was "exceptional" and that the response helped prevent injuries and further damage to the facility.

Cherry Point is the third-largest refinery on the West Coast and produces 20 percent of Washington's gasoline and the majority of jet fuel for Sea-Tac, Portland and Vancouver, B.C., airports.

The Associated Press contributed to this article.

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