MARTINEZ -- As Tesoro's Golden Eagle refinery dealt with the second acid spill in less than a month that required hospital treatment for workers, federal chemical safety officials said late Monday that the company had misrepresented to the public the extent of last month's incident.
The U.S. Chemical Safety Board said in a written statement that an "eye-opening" Tesoro document indicates that the Feb. 12 mishap resulted in the release of an estimated 84,000 pounds of sulfuric acid -- "hardly the minor release that Tesoro has been describing to the public."
The CSB said it was sending an investigator to probe Monday's spill. The agency said earlier Monday that it had regained access to the refinery near Martinez last week after Tesoro had prevented its investigators from returning to the site of the Feb. 12 incident.
Two employees were treated at a hospital Monday morning after they were exposed to sulfuric acid, Contra Costa County Hazardous Materials specialist Maria Duazo said.
Refinery officials contacted the agency at 10:49 a.m. and reported that two contract employees suffered sulfuric acid burns, she said. The workers, she added, both wore protective clothing.
Fire crews responded to the refinery, and the workers were taken by ambulance to John Muir Medical Center in Walnut Creek for serious but not life-threatening injuries.
The state's worker safety regulatory agency, Cal/OSHA, was also responding to the scene Monday, agency spokesman Peter Melton said. It issued an order for Tesoro to preserve the site of the accident.
Tesoro spokeswoman Tina Barbee wrote in an email Monday that the workers "were exposed to a chemical at a unit during planned maintenance activities."
Barbee wrote that the workers were wearing protective safety equipment and were decontaminated in a shower before being taken to the hospital, and that one has since been released.
The incident comes less than a month after two other workers were burned with sulfuric acid in the alkylation unit.
"The cause of (Monday's) incident is under investigation and is believed to be unrelated to the chemical release that occurred on Feb. 12," Barbee wrote.
Tesoro also disagreed with the CSB's assertion that the company misrepresented the scope of February's chemical release. "... (T)he release was contained in a process sewer, which is part of the system's design," Barbee wrote. "The amount of SO2 released to the environment was classified as minor according to regulatory requirements."
Cal/OSHA shut down the unit from Feb. 18 to Feb. 28 while it investigated the Feb. 12 incident. Late last month, federal chemical safety officials sent a sharply worded letter to Tesoro CEO Gregory Goff alleging that company officials violated federal law in blocking investigators from the site of the Feb. 12 accident.
Three U.S. Chemical Safety Board investigators showed up a day after the incident and initially gained access, but Tesoro's lawyers raised "jurisdictional challenges" and forced the investigators to leave, said Dan Horowitz, the CSB's managing director.
Horowitz wrote in an email Monday that CSB investigators had gained access to the facility last week.
Investigators "made progress," Horowitz wrote. "Tesoro has been cooperating to some extent."
In the statement released Monday, the Chemical Safety Board said Tesoro had yet to provide some of the key documents it is seeking, including a recent survey of safety culture. In addition, the CSB said evidence at the site had not been preserved.
The two workers who suffered injuries in the acid spill at the refinery last month were flown to UC Davis Medical Center and treated for first- and second-degree burns and released, according to a hospital spokeswoman.
In a prepared statement released Feb. 21, Tesoro spokeswoman Melissa Flynn said the company was "surprised" that CSB intended to investigate the incident, which she said resulted in "minor chemical burns" to two employees.
Federal law gives the CSB power to investigate "any accidental release resulting in a fatality, serious injury or substantial property damages," according to the legislative code that appears on the agency's website.