Refiners "may have to import it from places as far away as Singapore, South Korea and Australia," Van der Valk said, "which means that prices could go sharply higher in the coming days," especially if the refinery remains closed for more than a short period.
At the Richmond facility, Chevron said Tuesday that the main fire had been extinguished and officials were allowing "a small controlled burn … to reduce pressure."
Chevron spokeswoman Heather Kulp said the blaze was caused by "a vapor leak of hydrocarbon, similar to diesel," from the refinery's No. 4 crude unit, one of the first stops that oil makes in the refining process.
The leak was discovered about 4:15 p.m. Monday. Emergency personnel responded, but by 6:30 p.m. the leak increased, a fire broke out and personnel were evacuated from the immediate area.
Orders issued by Contra Costa County health and safety officials for those in surrounding areas to stay inside were lifted before midnight. Three employees suffered minor injuries and were treated on site, Kulp said.
Officials at the Doctors Medical Center in San Pablo, Calif., said hospital personnel examined 181 people from the area around the refinery who complained of symptoms that included respiratory problems and eye irritation. Most patients were released after being seen, the hospital said.
A filing with the California Emergency Management Agency showed that the fire released sulfur dioxide, nitrogen oxide, hydrogen oxide, sulfuric acid and nitrogen dioxide into the air, according to a statement released by Richmond.
"Concerns remain about inadequacies and delays in the communication system which reportedly notified only some residents about [staying inside], and not in a timely manner," the city said.
A health advisory remained in place while the controlled burning continued, the city said, noting that there still was "a big concern to local residents, especially the most vulnerable with respiratory conditions such as asthma and other breathing difficulties."
Richmond Mayor Gayle McLaughlin said she would call for an investigation and analysis from both Chevron and independent sources.
Chevron issued an apology to its neighbors and set up a claims process.
"We intend to compensate our neighbors for medical and property expenses incurred as a result of the incident," the company said Tuesday. "We will also see to it that communities will be reimbursed for the costs they face for emergency personnel who responded to last night's incident."
Several hundred people turned out Tuesday night for an emotional town hall meeting about the fire, filling every seat on the floor of the Richmond Memorial Auditorium and crowding the back of the cavernous room. Many carried signs, some wore protective face masks and one showed up in a full biohazard suit complete with gas mask. Several complained that the region's emergency warning system wasn't effective.
White reported from Los Angeles, La Ganga from Richmond.