( Reuters ) - A giant explosion rocked an oil refinery 290 miles west of Dallas on Monday morning, injuring at least four workers, company and public officials said.
Production at the 67,000 barrel per day Alon USA Energy Inc refinery in Big Spring, Texas, was shut by the 8:30 a.m. CST (9:30 a.m. EST) blast, a company spokesman said. Fires continued to burn off petrochemicals Monday night.
The explosion in the refinery's propylene unit rocked buildings miles from the plant, raising a mushroom cloud of black smoke that could be seen up to 40 miles away.
One worker was taken to a hospital with burns, but his condition was unknown, said Alon spokesman Blake Lewis. Another worker was examined for a possible concussion, while two others were being checked for injuries.
Schools, a local college and Interstate Highway 20, which passes by the refinery, were shut by the blast.
"It shook all of our community, rattled all of our buildings," said Big Spring Assistant Schools Superintendent Carrie Dunham.
Big Spring Mayor Russ McEwen said a woman was injured when debris smashed through her windshield as she was driving along Interstate 20. The driver was at home following treatment.
"There were no life-threatening injuries," McEwen said at a news conference near the refinery.
The fire was contained and under control by late Monday morning, but an asphalt tank was burning Monday night.
The explosion in the propylene unit "caused several places of fire, including asphalt tanks and slop oil tanks," according to a notice Alon filed Monday night with Texas pollution regulators.
Propylene is a refining by-product used in making plastics.
Lewis said the company did not know what set off the blast or which unit or units were involved.
No units at the refinery were being shut down or started up at the time of the explosion, he said. Unit start-ups are particularly risky events, when the threat of explosion is greatest.
No maintenance work was scheduled at the plant when the explosion took place, Lewis said, and there were no storms near the refinery at the time.
Lewis said Alon would continue to honor its supply contracts. The Big Spring refinery serves cities in north and west Texas and New Mexico.
Alon USA is majority owned by Alon Israel Oil Co Ltd. Alon USA also operates two refineries in California.
Local TV stations said the smoke plume was seen by weather radar.
"It's probably going to take some time to get it out," said Judge Mark Barr, administrative chief of Howard County.