Fire trucks are visible outside a steel plant on the Far South Side early this morning.

Fire trucks are visible outside a steel plant on the Far South Side early this morning. (WGN-TV)

An oil container at a large steel plant caught fire this morning on the Far South Side, but firefighters put out the blaze and reported no injuries.

The fire started about 4:30 a.m. inside the plant, which has a listed address in the 400 block of West 127th Street and runs three blocks by four blocks.

It was quickly elevated to a still-and-box alarm with a Level 1 hazardous materials response, with firefighters using foam as well as water to battle flames. The fire, which appeared to have started in an oil container, “self-vented” through holes in the roof possibly created by small explosions, Chicago Fire Department Chief Juan Hernandez said.

Workers were inside the plant at the time of the fire, but all managed to leave without incident, Hernandez said. No injuries were reported.

Firefighters extinguished the fire by 5:15 a.m.

asege@tribune.com

Twitter: @AdamSege