Crews worked to extinguish a fire that ignited at a Chevron oil refinery in El Segundo on Tuesday.

A massive blaze could be seen burning inside one particular section of the refinery just west of Sepulveda around 6:15 p.m.

It’s unclear what ignited the fire or what was housed in that portion of the building.

Emergency crews with Los Angeles County Fire, El Segundo Fire and Manhattan Beach Fire departments were dispatched to the scene along with the Chevron Fire Department.

Multiple fire crews could be seen working hard to extinguish the substantial flames. There is no current threat to nearby structures, officials said.

The blaze was fully extinguished around 8:30 p.m., officials confirm.

The cause remains under investigation.