At least 14 people were killed and more than 70 injured in a huge blast that ripped through a BP oil refinery in Texas on Wednesday.

Company spokesmen said today (Thursday) some people remain unaccounted for, more than 18 hours after the explosion in Texas City southeast of Houston.

The company has not identified the cause of the blast but says it does not suspect terrorism.

The explosion occurred in a part of the plant used to boost the octane level of gasoline. The refinery processes some 460-thousand barrels of crude oil per day -- accounting for 3 percent of the U.S. fuel supply.

Earlier this month, U.S. occupational safety officials fined the plant nearly 110-thousand dollars for an incident in which two workers were burned to death by superheated water.