A California oil refinery unit that was damaged by an explosion was already offline for unplanned maintenance when the fire occurred, industry analysts said Thursday.
The so-called fluid catalytic cracker unit refines gasoline and is critical to producing California-grade fuel.
The unit had been offline for two days because of problems when a different piece of equipment exploded, said the Oil Price Information Service, which tracks the oil industry.
The blast at the plant about 20 miles south of downtown Los Angeles caused a fire that shook the neighborhood on Wednesday and rained debris and ash on nearby lawns. Four contractors were taken to the hospital for evaluation of minor injuries.
It's not uncommon for refineries to take equipment offline for maintenance and most accidents happen as the refineries are going down for work or being brought back online after repairs, said Tom Kloza, global head of energy at the Oil Price Information Service.
The accident could cause gas prices in California to spike 15 to 20 cents a gallon but would not have an effect beyond the state because Californians use a unique blend of gasoline that's formulated to reduce pollution, particularly during the summer months, Kloza said.
The shutdown of gasoline production at another California plant due to labor unrest will put a further crimp on supply, he said.
It's still unclear how much damage the fluid catalytic cracking unit sustained or how long it will take to get it back online.
Todd Spitler, a spokesman for ExxonMobil, declined to answer questions about why the unit was offline before the blast but said an emailed update would be available later Thursday.
The refinery processes an average of 155,000 barrels of crude oil a day. It produces 1.8 billion gallons of gasoline a year, which accounts for about 8.3 percent of the state's total refining capacity.
Gas prices in California had been inching up even before the blast, which came at a time when refineries in the state are shifting production to summer-grade gasoline.
The unit where the explosion happened is critical to the refinery's ability to process gasoline and serious damage "would shut down gasoline production," said Pavel Molchanov, senior vice president of energy equity research at Raymond James & Associates.
The unit processes 100,000 barrels of crude oil a day — about two-thirds of the daily total for the entire refinery, he said.
The area of the refinery had been offline because the refinery was having problems with a recently repaired component called the alkylation unit, according to a report by the Oil Price Information Service. It wasn't clear if the recent repairs to the alkylation unit had anything to do with the explosion.
An electrostatic precipitator — a filtration device that removes particulates — exploded within the fluid catalytic cracker unit, sparking a fire, said Erika Monterroza, spokeswoman for the state Division of Occupational Safety, or Cal OHSA, which is investigating the blast.
The investigation could take up to six months, she said, and the refinery is prohibited from operating in the unit until the agency deems it is safe.
If state investigators find safety lapses, fines would top out at $25,000 per instance for a serious violation and $70,000 for a willful violation, Monterroza said.
The Torrance refinery has been fined more than $100,000 over the past five years for health and safety violations, most of them minor, according to state records. The largest fine — $18,000 — was for an accident that caused a 760-pound guide plate to land on a worker's foot.
The refinery was last inspected in November, Monterroza said.
