HOUSTON (Reuters) - Leading U.S. refiner Valero Energy Corp shut the gasoline-producing unit at its Texas City, Texas, refinery as state and federal agencies began probing the Thursday night explosion, which sent a plume of black smoke skyward but caused no major injuries.
Energy industry intelligence service Genscape said on Friday that Valero shut the 88,000-barrel-per-day (bpd) gasoline-producing fluidic catalytic cracking unit (FCCU) shortly after the explosion at about 5 p.m. local time (2200 GMT) on Thursday.
The explosion and fire took place in the 12,000-bpd alkylation unit at the 225,000-bpd refinery, sources told Reuters on Thursday.
Valero spokeswoman Lillian Riojas said on Friday the fire broke out on a depropanizer tower. The depropanizer processes propane produced in the alkylation unit’s reaction tower.
In the alkyklation process refining byproducts are converted into octane-boosting chemicals that are blended into gasoline.
Riojas said one employee was evaluated for possible medical problems as a precaution, but “showed no health issues.” The employee returned to work at the refinery on Friday.
Four contractors sustained minor injuries while exiting the area where the explosion occurred, she said.
A spokesman for the U.S. Occupational Safety and Health Administration said investigators from the workplace safety agency were at the refinery, located 42 miles (68 km) south of Houston.
“We have sent people there,” OSHA spokesman Juan Rodriguez said by phone. “Folks from our Houston South office are there.”
By law, OSHA must complete its probe within six months of the explosion, Rodriguez said.
A spokesman for the Texas Commission on Environmental Quality *(TECQ) said the state pollution control agency had people at the refinery on Thursday night.
TCEQ staff were onsite on Thursday to assess the incident and Valero’s emergency response actions, said spokesman Andrew Keese.
“A TCEQ investigation is ongoing,” Keese said.
A spokesman for the U.S. Environmental Protection Agency regional office in Dallas was not immediately available for comment.
Reporting by Erwin Seba; Editing by Richard Chang and Jonathan Oatis