Officials at Tesoro's Golden Eagle refinery near Martinez are working today to determine what caused a total power outage Wednesday that shut down the plant and prompted health officials to issue a shelter-in-place warning, a refinery spokesman said.
The power outage happened at about 4 p.m., said Ken Dami, external affairs representative for Texas-based Tesoro Corp.
According to Randy Sawyer, director of the Contra Costa Hazardous Materials program, the refinery's primary source of power comes from Foster Wheeler, an engineering and construction contractor and power equipment supplier. PG&E ordinarily supplies backup power to the refinery.
Sawyer said that when one power supply goes down, the other is designed to immediately provide backup power without interrupting refinery operations, but that's not what happened Wednesday.
Although the cause of the failure is still under investigation, it appears that PG&E experienced a power outage, which somehow tripped the Foster Wheeler co-generator, causing it to fail as well, Sawyer said.
When that happened, the entire refinery shut down, forcing operators to send large amounts of material to the refinery's flares.
"All of our equipment worked exactly as it was supposed to," Dami said, referring to the flare system.
Huge flames and a giant cloud of black smoke were visible from miles away.
Sawyer said that the flares burn more efficiently and don't create as much smoke when steam is added to the tip of the flare, but when the power went out, the refinery lost its ability to generate steam.
At about 4:30 p.m. the refinery, working with county health officials, issued a shelter-in-place warning for nearby communities and sirens were activated to alert residents.
By about 7 p.m., the shelter-in-place order, which is a Level 3 in the county's Community Warning System, was reduced to a Level 1, which meant that there was some visible flaring but no off-site impact was expected, Sawyer said.
Power was restored to the refinery at 7:53 p.m., which helped officials reduce the amount of material that was being sent to the flare, Dami said.
He said the refinery remained at a Level 1 today as officials worked to re-start the plant.
There were no injuries at the refinery, where more than 750 people work, Dami said.
Sawyer said that health officials, working with the county fire district and local hospitals, did not receive any reports of negative health impacts as a result of the release.
One member of the county's hazardous materials team detected a slight odor, but it appeared that the majority of the smoke and pollution was rising into the atmosphere and dissipating. Sawyer said that pollution most likely came down outside the immediate area.
Air samples that were collected both upwind and downwind from the plant during the incident will be taken to a laboratory for analysis, Sawyer said.
The Bay Area Air Quality Management District is also investigating the incident, Dami said.
Refinery officials are required to submit a report on the incident Tuesday to the health department, Sawyer said. A second report, which will include a root-cause analysis of the incident, is due in 30 days.
Although the refinery's address is at 150 Solano Way in Martinez, the 2,206-acre plant is actually located in an unincorporated area of Contra Costa County between Martinez and Concord.
The Golden Eagle refinery is the second-largest oil refinery in Northern California and has a crude oil capacity of 166,000 barrels per day. The plant produces gasoline, diesel, heavy fuel oils, liquefied petroleum gas and petroleum coke, according to the company's website.
Tesoro Corp. is headquartered in San Antonio, Texas.