The fire at the BP petrochemical plant on Wednesday triggered a major fire sending black smoke billowing into the sky.

"It was just a real loud explosion," local resident Mike Martin said. "It sounded like a sonic boom, and it shook the pictures bad enough to where it knocked them off the wall. And it frightened me, so I jumped out of bed."

Though what caused the blast is not yet known, authorities have ruled out terrorism as a cause.

It is feared that the fatalities may rise.

BP's Texas City plant is a sprawling industrial complex that stretches across 1200 acres with 30 refinery units.

The plant processes 460 million barrels of crude oil every day, producing 3% of the US gasoline supply. It employs about 2000 people.

Texas City is about 55km southeast of Houston.

Last March, there was a blast and fire at a BP refinery in Texas City.