Los Angeles fire officials say they've choked off a fire at an oil refinery south of downtown, but nearby schools are being urged to keep students indoors until the smoke clears.

The fire at the 300-acre Tesoro Corp. refinery in the Wilmington area was reported shortly after 5 a.m. and was confined to a coker unit.

Deputy Fire Chief Mario Rueda says the fire was extinguished in about three hours. The cause is under investigation.

The fire sent a huge plume of black smoke hundreds of feet into the air.

There were no injuries or evacuations, but a refinery spokeswoman says people within a mile of the refinery have been asked to stay indoors as a precaution.

The 300-acre facility refines 97,000 barrels of oil a day into gasoline, jet fuel and other products.

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