A fire on Friday caused by a leaking pipe flange may temporarily idle production at BP Plc's 225,000 barrel per day (bpd) Cherry Point refinery in Washington state, West Coast refined products trade sources said on Saturday.

The sole crude distillation unit (CDU) at the refinery in Ferndale, Washington, was shut following the 90-minute blaze, according to a notice the refinery filed with federal regulators overnight.

Wholesale gasoline prices in the Los Angeles market on Friday night jumped on news of the shut crude unit at the refinery, which is the largest in Washington state and third largest on the U.S. West Coast, the trade sources said on condition of anonymity.

The refinery accounts for 8.7 percent of crude oil refining capacity on the West Coast, which is isolated from Gulf Coast, Midwest and Rocky Mountain refineries by a lack of pipelines running to the Pacific.

The CDU is the heart of any refinery. It begins the process of refining crude oil and provides the feed that other units turn into finished fuel for cars, trucks and airplanes.

BP spokesman Scott Dean said the company may say more about refinery operations later on Saturday, but as of Saturday morning the refinery continued to operate. He declined to discuss the status of specific units following the blaze.

Other units at the refinery that produce finished gasoline, diesel and jet fuel can continue producing with feedstocks either on-hand, or in the case of a lengthy shutdown, purchased from suppliers, the sources said.

According to the notice the refinery filed overnight with the U.S. National Response Center, residual crude oil shot out of a flange in a pipe between a heater and the vacuum unit, which boosts production on the crude unit, igniting the blaze.

Only one minor injury was reported due to the fire and all workers at the refinery were accounted for on Friday.

Investigators from both federal and state agencies will begin a probe of the fire on Saturday, looking for failures in operating procedures and the emergency response.

Refinery workers will be checking refinery units for the extent of damage from the blaze to determine what repairs may be necessary and how long operations at the refinery 100 miles north of Seattle may be impaired.

The refinery received 12 citations in 2010 from the state's worker safety regulator, the Department of Labor & Industries, for serious violations in the safe management of processes involving highly hazardous chemicals at the hydrocracking unit.

BP did not appeal the 2010 citations, corrected the problems and paid $69,200 in fines, the department said in a press release at the time.

BP's Texas City, Texas, refinery was the site of one of the worst refinery disasters in the past decade when 15 workers were killed in a 2005 blast.

A federal investigation found extensive failures in the process safety management at the Texas City refinery. BP also launched an independent probe of safety at its U.S. refineries and found problems at all five of them. The company spent over $1 billion improving the Texas City refinery.

BP has been praised by the United Steelworkers union, which represents most U.S. refinery workers, for the efforts to improve safety at its refineries since the Texas City blast.

In Washington state, the most recent refinery explosion was a deadly blast in April 2010 at Tesoro Corp's Anacortes, Washington, refinery that claimed the lives of seven workers.

(Reporting by Erwin Seba; Editing by Paul Simao)